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Animals actively regulate the position and movement of their sensory systems to boost the quality and quantity of the sensory information they obtain. The rat vibrissal system is recognized to be an important model system in which to investigate such "active sensing" capabilities. The current study used high-speed video analysis to investigate whisker movements in untrained, freely moving rats encountering unexpected, vertical surfaces. A prominent feature of rat vibrissal movement is the repeated posterior–anterior sweep of the whiskers in which the macrovibrissae are seen to move largely in synchrony. Here we show that a second significant component of whisking behavior is the size of the arc, or "spread," between the whiskers. Observed spread is shown to vary over the whisk cycle and to substantially decrease during exploration of an unexpected surface. We further show that the timing of whisker movements is affected by surface contact such that 1) the whiskers rapidly cease forward protraction following an initial, unexpected contact, and may do so even more rapidly following contact with the same surface in the subsequent whisk cycle, and 2) retraction velocity is reduced following this latter contact, leading to longer second-contact durations. This evidence is taken to support two hypotheses: 1) that the relative velocities of different whiskers may be actively controlled by the rat and 2) that control of whisker velocity and timing may serve to increase the number and duration of whisker–surface contacts while ensuring that such contacts are made with a light touch.
Adult rats sweep their large facial whiskers (macrovibrissae) back and forth in a rhythmic behavior known as whisking, observed under most conditions of natural locomotion and exploration (Carvell and Simons 1990; Gustafson and Felbain-Keramidas 1977; Hartmann 2001; Vincent 1912). Recent research has demonstrated that exploratory whisking, in freely moving animals, often diverges from the regular, largely bilaterally symmetric and synchronous motor pattern that has been recorded when immobilized rats are trained to whisk in air (e.g., Bermejo et al. 2002; Gao et al. 2001). Specifically, asymmetries, asynchronies, and changes in whisk amplitude and frequency have been documented (Berg and Kleinfeld 2003; Carvell and Simons 1990; Mitchinson et al. 2007; Sachdev et al. 2003; Sellien et al. 2005; Towal and Hartmann 2006, 2008) that may be the consequence of "active sensing" control strategies. Such strategies use sensor information, or task knowledge, to control the position and movement of the sensory apparatus in a manner likely to boost the amount of useful sensory information obtained (Aloimonos et al. 1988; Ballard 1991; Gibson 1962; Lungarella et al. 2005). In the current study we set out to discover whether other aspects of whisker control might also be subject to this kind of active regulation and to identify some of the likely sensory consequences of these forms of anticipatory control.
Our specific focus concerns how the rat modifies the movements of its whiskers, and of its head and body, over the course of a sequence of whisk cycles during which contact is made with an unexpected vertical surface. We have previously demonstrated immediate, contact-induced changes in the timing of whisker control and longer-term, anticipatory modulations of whisk amplitude (Mitchinson et al. 2007). Here we will present evidence of changes in a further whisking parameter: the relative spacing, or "spread," between adjacent whiskers. We will provide data suggesting that this measure not only captures a significant, and previously unquantified, fraction of variance in whisking behavior, but that it also appears to be modified by active control mechanisms following contact and in anticipation of further contacts.
During exploratory whisking, the initial contact with a vertical surface triggers a rapid cessation of whisker protraction (and commencement of retraction) such that the whiskers palpate the surface with a relatively light touch (Mitchinson et al. 2007). We have termed this active control strategy "minimal impingement," since whisker movements appear to be modulated to reduce whisker bending (impingement) against the contacted surface. The investigation of such whisking control strategies is important to understanding the nature of the tactile stimuli that are processed in upstream neural centers, such as the somatosensory cortex, during natural behavior. For instance, evidence for "minimal impingement" strategies suggests that the whisker stimuli that are transmitted to these structures may be less intense than might otherwise be expected, whereas "maximal contact" strategies that involve regulating whisk amplitude or spread, could lead us to expect greater numbers of whisker–surface contacts than if control is not subject to such modulation. A further important parameter for understanding upstream sensory processing is the duration of whisker–surface contacts: while the whiskers are in contact with the surface the animal may be able to extract useful information about surface shape or texture. Our investigation will therefore also consider how differential control of whisker movements during interactions with surfaces could influence these important determinants of the tactile signals processed by the rat brain.
Experimental procedures
Ten male Royal College of Surgeons (RCS) dystrophic rats, aged 6–18 mo and weighing 250–350 g, were used. All animals had genetic retinal degeneration (dystrophy) and thus minimal vision; they were therefore strongly reliant on tactile information from their whiskers during locomotion and exploration behavior. Hetherington et al. (2000) previously showed that the capacity to orient to whisker stimulation is unimpaired in dystrophic RCS animals compared with other rat strains, although they did note a deficit in orienting to a tactile stimulus on the flank. Observations in our laboratory of dystrophic and nondystrophic RCS animals and of sighted Hooded Lister rats suggest that whisking control in dystrophic animals does not deviate in any marked way from that of normally sighted rats. All animals were kept in a 12-h dark/light cycle at 22°C, with unrestricted access to water and food; tested during the dark (active) part of their daily cycle; and handled prior to being placed in the experimental arena. All procedures were approved by the local Ethics Committee and UK Home Office, under the terms of the UK Animals (Scientific Procedures) Act of 1986.
Digital video recordings were made using a Photron Fastcam PCI camera, recording at 500 frames/s, shutter speed of 0.5 ms, and resolution of 1,024 × 1,024. The camera was suspended from the ceiling above a custom-built rectangular (40 × 40 cm) viewing arena with a glass floor, ceiling, and end-wall (see Supplemental Fig. S1).1 The arena contained a front-silvered mirror, positioned behind the end-wall, to afford two viewpoints to the camera. The camera was also positioned so that it looked directly down the end and side walls in the overhead view; the front-silvered mirror was angled at about 45° so that the camera looked along the surface of the floor in the reflected, end-on view. The arena was illuminated from below by a custom-built, high-power light box, and from the far end of the arena facing the end-wall by a second, suitably angled mirror. The design and geometry of the arena thus provided uniform backlighting in two dimensions, with the field of view of the camera covering close to 20 × 20 cm in the overhead view and 8 × 20 cm in the end-on view. To obtain an accurate measure of camera/arena geometry a recording was also made of a three-dimensional (3D) calibration tool, with known shape and location, following initial positioning of the camera.
Opportunistic recordings, each 3–4 s in length, were taken of awake, unrestrained animals engaged in active, exploratory behavior. Each animal was filmed on between 2 and 11 occasions with ≤12 clips recorded, per rat, in each filming session. Each recording was initiated by an experimenter viewing the camera scene on a monitor window and pressing a trigger when the animal entered the field of view. In all, 334 recordings were obtained in this way with between 15 and 82 per animal.
Data selection
Video clips were selected for whisker tracking and detailed analysis as follows. To qualify for analysis each video was required to contain three consecutive whisks during which the rat approached and contacted an identified arena wall, with whiskers on the side of the snout ipsilateral to the initial contact clearly visible in the overhead view throughout. Furthermore, these three whisks were required to be of the following types:
) An initial precontact whisk, in which the whiskers did not contact the identified wall
) A first-contact whisk, in which at least two whiskers made contact with this vertical surface
) A second-contact whisk, in which the same two whiskers, and possibly others, made a further contact with the same surface
The constraint that there should be contacts on at least two whiskers in each cycle was enforced to reduce the possibility of including clips in which surface contacts were so slight that they might be below the rat's detection thresholds (Stuttgen et al. 2006). The requirement that the same two whiskers made the initial contact with the wall, in both the first- and second-contact whisks, was enforced to exclude some of the more atypical interactions with surfaces. In all, 60 clips (between 1 and 15 per animal) were identified that satisfied these criteria.
We note that the clips selected for analysis do not, in general, record the animal's first experience of the experimental arena. However, in sightless animals, anticipation of a surface prior to whisker contact would require the synthesis of path integration information with acquired knowledge of the arena configuration. Due to the accumulation of error in neuronal path integration mechanisms and evidence that such mechanisms may be specialized toward encoding position with respect to a home base (Etienne et al. 1996), it is unlikely that the RCS rat will have access to an accurate estimate of the relative position of a wall following a period of roaming, during which there was no tactile contact with that surface. In the clips we analyzed, then, the initial contact with the wall, in the first-contact whisk, was considered to be "unexpected" in the sense that the animal is assumed to lack accurate prior knowledge of its own position relative to that surface prior to contact. More generally, our results do not require that the rat has no prior knowledge of nearby surfaces, but rather that the initial whisker contact provides information that greatly improves the animal's capacity to localize a nearby surface and is therefore useful for directing subsequent exploratory behavior.
Whisker tracking and head tracking
For the 60 selected clips, and for each of the three selected whisks, five whiskers, ipsilateral to the initial contact, were tracked on an LCD flat-screen monitor by a human observer using uncompressed video and a purpose-built tracking tool. Whisker tracking, in this case, used only the overhead view and involved tracking two points, one near the base of the whisker, the other two thirds of the way out along the whisker shaft (see Supplemental Fig. S1). This is referred to as the overhead tracking set in the following text. The tracked whiskers were assumed to correspond to whisker columns 0–4, although our results do not depend on this assumption. To estimate head movements, the tip of the snout and the midpoint of the head were also tracked in the overhead view and the height of the snout above the floor in the end-on view. Note that, although technologies have recently been developed for automated tracking of whisker movement (Knutsen et al. 2005, 2008; Voigts et al. 2008), the difficult problem of tracking multiple whiskers in a complete, intact whisker field has yet to be automated. No smoothing was performed on the tracked whisker angular position or head-movement data; for whisker velocity a moving average filter that computes a running average of three adjacent points was used to reduce any effects of tracking inaccuracies.
The overhead tracking data for each clip were analyzed to obtain the descriptive measures listed in Table 1. For the calculation of per-whisk summary measures (Table 1, B and D) the point of minimum protraction between two successive protraction–retraction phases was taken as the separation boundary between consecutive whisks. The clips were also examined to determine whether contacts with the target surface, in the first-contact whisk, occurred on one side or both sides of the snout. Two subsets were identified for further analysis: 1) the unilateral set (n = 25) in which contact, during the first-contact whisk, was on one side only, and 2) the bilateral set (n = 35) in which there were whisker–surface contacts on both sides of the snout in the first-contact whisk. Further details concerning our tracking and data analysis methods are provided in the Supplement, including raw data (whisker trajectories) for two exemplar clips (Supplemental Fig. S4).
3D whisker-tip trajectory reconstruction
To better evaluate the contribution of head movements to the patterns of whisker movement observed in the overhead view, four representative clips were selected for 3D reconstruction of whisker-tip trajectories. Tracking and trajectory reconstruction, using a stereo correspondence algorithm, were performed as described in the Supplemental Material.
Statistical considerations
The primary focus of this investigation was on contrasts within triplets of consecutive whisks; data were therefore pooled across animals with the video clip of each tracked whisking episode taken as the fundamental unit for analysis. Except where otherwise specified the results presented were calculated for the 60 selected clips in the overhead tracking data set. MANOVA was used to test for overall differences between whisk types in relation to each of the main classes of data, with univariate ANOVAs and appropriate post hoc tests used to examine differences on specific variables. An alpha-level of 0.05 (two-tailed) was used for statistical tests corrected for multiple comparisons, when required, using a Bonferroni correction. Significant results are summarized in the following text and figures, with SE bars included in graphs where appropriate. Further details of statistical analyses, including tables of all univariate ANOVA tests, including means, SDs, F-values, and effect sizes, are provided in the Supplemental Material.
Our presentation of results is structured as follows. In the next section we provide a principal components analysis (PCA) of our whisker position data and show that the two main components of these data, determined algorithmically, correspond with the theoretically meaningful measures of the mean angular position of the whiskers and whisker spread. Next, in Variation across whisk types in summary measures of whisker control, whisker–surface contacts, and head position, we quantitatively characterize the whisking behavior of the rat during exploration of an unexpected surface by analyzing variation in summary measures of whisk control (Table 1B), surface contact (Table 1C), and head movement (Table 1D). Armed with a good understanding of the differences between the three whisk types, A closer look at whisker spread then considers whisker spread in more detail, evaluating several alternatives to the hypothesis that spread is controlled using differential whisker velocities and in anticipation of surface contacts. Finding that anticipatory control of whisker velocity is supported by the available data, Sensory consequences of whisker control then examines whether such control is consistent with a "maximizing contact" strategy. We then turn our attention to the "minimal impingement" aspect of our active touch hypothesis and consider whether this is supported by our new data concerning the timing of cessation of protraction following contact. Finally, we look at the duration of whisker–surface contacts and explore the relationship of this important variable to several elements of whisker control, particularly the angular velocity of the whiskers during the retraction phase.
Principal components of whisker configurations
To better characterize the nature of rat whisking control a PCA analysis was run on the raw whisker angular position data from all five tracked whiskers and across all three specified whisk types (precontact, first contact, second contact). Three components were found to be present in this data set, as illustrated in Fig. 1.
Component 1 explained 80.4% (precontact whisk), 76.8% (first contact), and 70.1% (second contact) of the variance in whisker positions (Fig. 1, top) and was extremely well correlated (r > 0.99) with the mean angular position across all whisk types. Thus as might be expected since whisker movement is strongly synchronized, the average protraction angle of the whisker field strongly predicts the positions of all the tracked whiskers.
Component 2 explained 13.4% (precontact whisk), 15.5% (first contact), and 20.2% (second contact) of the variance in whisker positions (Fig. 1, center) and was well correlated with whisker spread (precontact: r = 0.90; first contact: r = 0.91; second contact: r = 0.92). Therefore the overall change in the angular separation of the whiskers constitutes the second most important parameter for describing the spatial arrangement of the whiskers at any time during the whisk.
Component 3 explained 3.1% (precontact whisk), 3.8% (first contact), and 4.6% (second contact) of the variance in whisker positions (Fig. 1, bottom), but was not significantly correlated with any of the measured whisking parameters. Component 3 is best described as the middle whisker columns (1–3), tending to be more protracted than the two outer columns (0 and 4). Although the proportion of variance explained is small, this component was present in every whisk type, suggesting it is unlikely to be an artifact of the measurement/analysis process (in contrast, components 4 and 5 did not have a consistent shape across whisk types and so are probably not meaningful).
In summary, then, although the whiskers largely move as a group (70–80% of variance captured by their mean angular position), there is important variation in relative whisker positions (13–20%) that is well characterized by the measure of whisker spread. Using these two components together can account for 90–94% of all the variance in the whisker position data seen in the overhead view. In other words, given just these two values for each frame we could reconstruct the actual angular positions of all five tracked whiskers to this level of accuracy.
Having established mean angular position and spread as the two most informative parameters for describing whisker configurations it is useful to briefly consider the phase relationship of the two measures over the course of the whisk cycle. In Supplemental Fig. S5 we show, using cross-covariance analysis, that in the precontact and first-contact whisks, spread peaks reliably 0–6 ms before angular position. However, this relationship breaks down somewhat in the second-contact whisk, where we see a much weaker coupling between the two measures with out-of-phase relationships (>10-ms difference between the angular position and spread peaks) in 26 (43%) of the 60 whisks. The temporal relationship between spread and angular position seen in the precontact and first-contact whisks is consistent with observations by Sachdev et al. (2002), made in head-fixed animals whisking in air, who described the spread as being maximal at, or close to, maximum protraction. That this relationship is much less in evidence for the second-contact whisk is consistent with the hypothesis, explored in the following text, that active control mechanisms may be influencing whisker spread when the rat is able to anticipate contact with a vertical surface.
Variation across whisk types in summary measures of whisker control, whisker–surface contacts, and head position
To begin our investigation of changes in whisk control following unexpected surface contacts a MANOVA was conducted using whisk type as a three-way within-subjects factor and the summary whisker movement measures (Table 1B) maximum protraction angle, minimum protraction angle, mean spread, mean protraction velocity, mean retraction velocity, and whisk duration as dependant variables. This analysis revealed a significant multivariate difference between whisk types (P < 0.001). To determine which aspects of whisking were contributing to this result, separate three-way univariate ANOVAs were then carried out on each of these six variables as detailed in Supplemental Table S1. All of the analyzed variables showed reductions between the precontact and second-contact whisk, with the first-contact whisk being, on the whole, more similar to the precontact whisk than to the second-contact whisk (as indicated by post hoc tests). Two parameters, in particular, stood out as showing large changes by the second-contact whisk—the mean spread and the mean retraction velocity. These measures fell by 21% (P < 0.001) and 22% (P < 0.001), respectively, over the course of the three whisks. Smaller but still significant changes also occurred in minimum and maximum protraction angles of the whisk (7 and 10%, P < 0.001). Figure 2 provides graphs illustrating each of the significant trends in whisk protraction angle, spread, and velocity. Examples of the reduction in overall spread are also provided in Supplemental Video S1 and in the sequence of snapshots in Fig. 3. Comparison of clips with bilateral and unilateral first contacts found a significant interaction effect between whisk type and whether the initial contact was on one side or both sides (P < 0.001; see Supplemental Fig. S6), indicating that the reduction in spread across whisks was more pronounced on occasions where there were bilateral surface contacts.
We next examine the relationship between whisker movement and surface contact for the two contact whisks. Four variables that have potentially important sensory consequences—and therefore deserve attention—are the number of whisker contacts, the angular velocity and angular position of the whisker at the point of contact, and the duration of whisker–surface contact (see Table 1C for definitions). Further, since we previously proposed "minimal impingement" as a general characteristic of exploratory whisking (Mitchinson et al. 2007) we will also examine the time from contact to maximum protraction, predicting that control of whisker movement following contact will show rapid cessation of protraction in both the first- and second-contact whisks. Two limitations of the analyzed data should be made clear: First, our measure of the number of whisker contacts is the number of tracked whiskers touching the vertical surface during the whisk cycle of interest and not the total number of contacting whiskers (which is difficult to measure from video recordings). Second, contact duration was calculated for only the first whisker to touch the surface, although this is also generally the last whisker to leave the surface. Furthermore, in 25 (42%) of the second-contact whisks contact continued beyond the end of the whisk cycle. Contact duration measures for these whisks were therefore calculated as the time from the initial contact, in that whisk, to the end of the whisk cycle.
A MANOVA for the preceding contact-related measures again showed a large difference between whisk types (P < 0.001). Subsequent univariate analyses (Supplemental Table S2) found that there were more contacts on tracked whiskers in the second-contact whisk (+14%, P = 0.001), that second contacts occurred at smaller angular positions (−9%, P < 0.001), and that the mean duration of contacts was markedly longer in second-contact whisks compared with first-contact whisks (+40%, P < 0.001). Mean time from contact to maximum protraction was found to be <15 ms in both whisks (14.3 and 11.3 ms for the first- and second-contact whisks, respectively), consistent with the "minimal impingement" hypothesis. The findings of more contacts, longer contact durations, and rapid cessation of protraction will each be subsequently examined further in Sensory consequences of whisker control. To conclude the current section, however, we briefly consider the impact of head movements on whisking control and on whisker–surface contacts.
Although our primary focus here is on changes in whisker movements it is important to consider whether there may be consistent patterns in the positioning and movement of the rat head during exploratory whisking. This matters both because head movement can influence the sensory consequences of whisking (movement toward a surface, for instance, will increase bending of any contacting whiskers) and because head/body movement is likely to be an important element of the overall control strategy used by the rat to position its whiskers. The head position and movement parameters listed in Table 1D were selected for quantitative analysis as being most relevant to understanding whisker movement and positioning with respect to a vertical surface. An initial MANOVA again showed a strongly significant difference between whisk types (P < 0.001), whereas subsequent univariate ANOVAs (Supplemental Table S3) showed that the mean distance to the wall and the mean velocity toward the wall both decreased by >50% (P < 0.001) by the second-contact whisk. Meanwhile, the vertical velocity of the snout (a useful indicator of the change in head tilt) increased 56% by the second-contact whisk (P = 0.021). By including measures of head rotation and movement along the wall (parallel to the floor), we can estimate that, during a typical approximately 100-ms whisk cycle, each rat moved 9–12 mm horizontally, raised or lowered its snout by 6–10 mm, and rotated its head through 5–6°. In other words, these animals were rarely stationary and often moved at quite significant speeds while exploring nearby surfaces with their whiskers.
The above-cited findings suggest that the rat's head and body movements during whisking may be of sufficient magnitude to influence the nature of whisker deflections. These impacts could arise either by changing the effective speed of the whiskers as they meet the contacted surface, by changing the duration of contact, or by causing movement of the whisker shaft as it "sticks" or "slips" (Ritt et al. 2008) across a surface. Here we consider the likely impact of head movement on the effective velocity of the initial contact; effects during contacts will be briefly considered in Sensory consequences of whisker control.
Because the surfaces in our arena are flat, the vast majority of whisker–surface contacts in our data set were observed to begin at or near the tip of the whisker. We therefore make the simplifying assumption that the velocity at the whisker tip is a good approximation for the velocity at the point of contact on the whisker shaft. Using measurements of the lengths of contacting whiskers estimated over three successive video frames, and the formula we estimate that the mean velocity at the tip, immediately prior to contact, was 0.44 mm/ms in both the first- and second-contact whisks (SD 0.32 and 0.38, respectively). Mean head angular velocity of about 6°, in both contact whisk types, suggests that the effective tip velocity could increase or decrease by ±5% as the result of head rotation in a typical whisk. Combining whisker tip and head translation velocities (which were predominantly positive in both whisks) suggests that movement toward the wall increased the effective tip velocity at contact by around 27% to 0.60 mm/ms (SD 0.34) in the first-contact whisk and by 13% to 0.55 mm/ms (SD 0.38) in the second. Overall, then, we can conclude that head movements contributed significantly to the velocity of whisker–surface impacts.
A closer look at whisker spread
In the previous two sections, whisker spread was first identified as the second largest component of whisking behavior, and then as one of the two whisker movement parameters (the other being retraction velocity, which we will subsequently consider) that change most significantly when a rat explores an unexpected vertical surface. We propose the hypothesis that variation in observed whisker spread is at least partly the consequence of differential control of whisker velocity and that significant changes in spread arise in response to surface contacts and in anticipation of future contacts. Evidence in support of this view will be provided in this section by evaluating, and presenting evidence against, three alternative explanations of the data presented so far: 1) that variations in apparent spread occur primarily as the consequence of head movements (particularly head tilt) and thus do not arise from differences in how the whiskers themselves are controlled; 2) that variation in spread across whisks arises as the result of correlated changes in other whisker control parameters and can be reduced or eliminated by controlling for these covariates; and 3) that changes in spread occur only after surface contacts and not prior to, and in anticipation of, such contacts.
As previously noted, a change in the orientation of the whisking plane can substantially affect the apparent spacing between whiskers observed in the overhead view; thus the differences in whisker spread that we have identified could have arisen partly, or wholly, as the consequence of changes in head position. To investigate this possibility we performed three analyses.
First, we looked separately at the protraction velocities for the most rostral and caudal tracked whiskers across each of the whisk types. We know from Fig. 2 that the whiskers are, overall, moving slightly more slowly in the second-contact whisk, although for spread to be reduced in this whisk the most caudal whiskers will have to match their velocities more closely to those of the rostral ones. This is true, of course, only if the changes in spread are the consequence of differential control of whisker velocities. If changes in observed spread are the result of head movement, then we should expect to see corresponding changes in whisker velocity, but all whiskers should be affected equally as they move in approximately parallel trajectories (see, e.g., Bermejo et al. 2002 and Fig. 6). In other words, head-movement and whisker-movement explanations of spread make quite different predictions concerning individual whisker velocities. A 3 × 2 ANOVA of the relevant whisker velocity data is provided in Supplemental Table S4 and the key results are summarized in Fig. 4. Here we see that although the more rostral whiskers did protract faster than the most caudal ones overall (P < 0.001), there was a significant interaction (P < 0.001) such that by the second-contact whisk, both rostral and caudal whiskers were moving at approximately the same speed and the most caudal whiskers were moving faster than in the preceding whisks. Since this result cannot be explained by head movement we therefore conclude that a significant part of the observed variance in whisker spread is due to the way in which the whiskers themselves are controlled.
Second, to investigate the possible effects of changes in head position on observed spread we plotted a scattergram, shown in Fig. 5, of snout elevation (used as an indicator of degree head tilt) versus mean spread for all three whisk types in all 60 clips. We then fitted separate polynomial curves to this distribution for each whisk type. Two observations arise from inspecting these figures. First, and most important, it can be seen that the curve for the second-contact whisk data lies beneath that for the other two types and does not overlap them at any point. This confirms that the observed reduction in spread in that whisk type, compared with the others, is relatively independent of this measure of head position. Second, it is noteworthy that all three curves in Fig. 5 are mildly U-shaped, with the largest spread values occurring when the snout is near the floor or the ceiling and the smallest when the snout is at medium height. Since the same five whiskers are tracked in all frames, this is the opposite of what one would expect if spread, as recorded in the overhead camera, was changing solely, or primarily, as the result of changes in head tilt. In that case, spread should be maximal somewhere in the central range of elevations, where whisker motion is parallel with the viewing plane of the camera, and should be smallest at the extremes, where the whisking plane angles away from, or toward, the camera. That the range of spread values for different snout elevations shows the opposite trend implies that tracking in the overhead view may be causing us to underestimate, rather than overestimate, the extent to which spread is varying within the plane of whisker movement at different head tilts.
Finally, we looked at some illustrative data that compare whisker spread, as measured in the overhead view, with an alternative estimate of relative whisker spacing calculated within a coordinate frame defined by the whiskers themselves. Specifically, two representative clips were chosen for tracking in both overhead and end-on views and 3D trajectories calculated for a subset of whisker tips as described in the Supplemental Material. For both clips we then computed a per-frame, head-invariant spread measure as the average distance between all pairs of tracked whisker tip positions. A comparison between this new estimate of whisker spacing and the original viewpoint-dependent spread measure, for both whisking episodes, is shown in Supplemental Fig. S7. These graphs show a reasonable match between the two measures (Pearson's r correlations of 0.72 and 0.54 for the two clips) and a similar reduction in spread over the three whisk types, confirming that spread, as measured in the overhead view, captures a significant portion of the variance of a measure of whisker spacing that is independent of head movement.
In a multivariate analysis it is important to control for the possible effects of covariates on a measure of interest. In this case, when calculated across all whisk types (i.e., n = 180), whisker spread was found to have a significant, though relatively small, positive correlation with maximum protraction (r = +0.18, P = 0.015) and a nonsignificant but positive correlation with minimum protraction (r = +0.14, P = 0.068) (correlations with other measured whisking parameters were negligible). These relationships are potentially important because we know that both maximum and minimum protractions are reduced on the second-contact whisk (Fig. 2). To establish whether variation in spread is independent of these other differences between whisk types, a univariate ANOVA (see Supplemental Table S5) was performed using values of mean spread calculated solely within the arc x to y degrees of the protraction phase, where x = max (minimum protraction) and y = min (maximum protraction), and where x and y were calculated separately within each clip across all three whisk types. After controlling for differences in minimum and maximum protractions in this way, mean spread was still found to decrease substantially by the second-contact whisk (P < 0.001) and by 17.9% compared with the precontact whisk, which is a similar reduction to that seen overall in the protraction phase (16.5%). We therefore conclude that the variation in spread seen across whisk types is not explained by differences in the protraction start and end positions.
Differences in observed spread between precontact and contact whisks could occur throughout the whisk cycle or could arise, primarily or wholly, as the result of changes in whisker movement taking place after the whiskers have touched the surface. To determine whether there were significant changes in whisker spread prior to any surface contact, an analysis (see Table S5) was conducted in which mean spread was calculated solely within the arc x to z degrees of the protraction phase where x = max (minimum protraction) (as above) and z = min (mean angular position prior to contact). Again, as in the previous test, mean spread still showed a significant decrease (−14.3%, P < 0.001) by the second-contact whisk, confirming that there is a significant reduction in whisker spacing prior to surface contact. In this context it is also worth looking briefly at differences in spread in the retraction phase of the whisk. Again, and as expected, this showed a significant reduction across the whisk types (P < 0.001); however, notably, here the reduction in spread began in the first-contact whisk (−14.1% compared with precontact). This result suggests that, following the initial contact, whisker control begins to adapt almost immediately to provide reduced whisker spread during further exploration of the contacted surface.
Sensory consequences of whisker control
The active touch hypothesis for rat whisking postulates that the control of whisker positioning is regulated on a moment-to-moment basis to provide the animal with better or more task-relevant tactile sensory signals. In this final subsection we examine three aspects of whisker–surface interactions—the quantity of whisker–surface contacts, the amount of bending during contacts, and the duration of contacts—and attempt to pinpoint some of the elements of whisker control that could be actively regulated to modify each of them.
Reducing spread through differential control of whisker movement brings the whisker tips closer together and should allow the rat to increase the density of sensory signals from targeted regions of space where objects or surfaces are expected. To verify this "maximizing contact" effect we calculated correlations between the number of contacts on tracked whiskers and a range of potential predictor variables for the combined set of 120 first- and second-contact whisks; a stepwise multiple linear regression was then performed using the most promising candidate predictors. This analysis showed that the number of contacts increased both with the inverse mean spread (lower values of spread are most discriminative), which showed a part correlation of +0.202 (P = 0.019) after removing the affects of other predictors, and with increasing snout elevation (part correlation +0.195, P = 0.024). Further details of these analyses, together with residual plots confirming that the relationships were approximately linear, are provided in the Supplemental Material. We conclude that the rat can increase the number of surface contacts by reducing whisker spread. The increase in contacts due to greater snout elevation remains to be explained and is briefly considered next.
Figure 6 shows the whisker tip trajectories for a first-contact whisk (left) and a second-contact whisk (right), calculated using tracking data from both camera views using our 3D trajectory reconstruction algorithm, and then rotated (in the bottom half of the figure) so that the trajectories can be observed in a plane perpendicular to both the wall and the arena. For illustrative purposes the tracked video clips used to generate these trajectories are also provided as Supplemental Videos S2 and S3. The left panel shows that during a whisk with low elevation many whiskers, and particularly the more caudal ones, make contact with the floor and would do so even if the rat were closer to the wall. Increased floor contact and reduced wall contact are likely simply because the rat's head tilts down toward the floor at a significant angle. For the whisk with higher snout elevation, shown in the right panel, whisker movement is close to being perpendicular to the wall, and the head position near horizontal, so we can expect, and do observe, many more wall contacts and few floor contacts. What happens for still higher elevations? When the head tilts above the horizontal this will bring some of the longer more caudal whiskers closer to the wall, increasing the likelihood that these whiskers will touch even as some of the dorsal whiskers rotate away from the wall (and may begin to touch the ceiling). We can thus conclude that tilting the head upward is, overall, a useful "maximizing contact" strategy for exploring walls, whereas tilting downward is clearly favorable for whisking during floor traversal.
In our previous study (Mitchinson et al. 2007) we found that, following a unilateral surface contact, the whiskers on that side of the snout cease protraction on average 13 ms after the initial touch. In the current study we used a larger sample size (60 vs. 22 clips), a higher frame rate (500 vs. 250 frames/s), and measured the average time from contact to maximum protraction across all five tracked whiskers. Performing this analysis for data from the first-contact whisk produced a mean time to maximum protraction of 14.3 ms—i.e., a result that is well within the expected margin of error of our previous investigation (±2 ms). When the same calculation was performed for the second-contact whisk, interestingly, the time to maximum protraction fell to 11.3 ms, a latency that was marginally faster than that for the first contact, although this result should be treated with some caution due to the relatively high P value (0.038, which exceeds the Bonferroni corrected alpha of 0.01). To further test the robustness of these estimates we separately examined the time to maximum protraction for each of the tracked whisker columns. As shown in Supplemental Fig. S9, the difference between first- and second-contact whisks was found consistently across all columns, whereas there was also an interesting trend for the more rostral whiskers to reach maximum protraction earlier than the more caudal ones by up to 5 ms. Time to maximum protraction was also compared for whisker columns that did, and did not, make contact with the wall; these were found to be very similar (P = 0.974), indicating that the contacts themselves were not significantly distorting this measure. An analysis by contact type (bilateral vs. unilateral; see Supplemental Fig. S10) also found no significant effect on the timing of maximum protraction (P = 0.095). Overall then we can conclude that rapid cessation of protraction is a general and consistent feature of whisker–surface contacts during exploratory whisking, which may possibly be more pronounced (faster) in subsequent whisks that in the initial contact, and whose effect will be to reduce bending of the whiskers against the surface compared with nonmodulated whisks.
On first inspection, the finding that whisker–surface contacts have much longer duration appears to be inconsistent with the rapid cessation of protraction and reduced head velocity toward the wall in the second-contact whisk. However, the likely explanation for these longer contact times is easily found by reviewing Fig. 2—here we saw that whisk retraction velocity was at a significantly slower pace on the second-contact whisk than on the first. To understand this further, we next divided the retraction phase into two halves and found that the decrease in retraction velocity in the second-contact whisk was much more evident in the first half of the retraction phase (−54%, P < 0.001) than in the second half (−9%, P = 0.237). This establishes that slower retraction occurs during the period of the whisk immediately following peak protraction and is thus most likely to influence contact duration. To confirm that retraction velocity was genuinely slower following the second contact, and not simply that drag on the contacting whiskers created the appearance of slower retraction, we looked at retraction velocity on the most caudal tracked whisker, since this rarely contacts the vertical surface (only three contacts in the 60 second-contact whisks). For this whisker, too, velocity during the first half of the retraction phase was also considerably slower on the second-contact whisk (−49% compared with −47% for the most rostral whisker, both P < 0.001). Details of each of these analyses are provided in Supplemental Table S6.
To further establish which control factors most influence contact duration we performed a stepwise multiple linear regression using head- and whisker-movement parameters that were likely predictors of duration. The dependent variable was contact duration measured for the 95 first- and second-contact whisks in which contact with the surface ceased before the end of the whisk cycle (60 first-contact and 35 second-contact whisks). This analysis showed that contact duration was most strongly predicted by time from contact to maximum protraction (part correlation of r = +0.487), retraction velocity (r = −0.293), snout vertical velocity (r = −0.246), and snout elevation (r = +0.183). Further details of this analysis, including residual plots confirming that the relationships were approximately linear, are provided in the Supplemental Material. The high positive correlation with the time from contact to maximum protraction confirms the importance of controlling protraction cessation, using sensory feedback, to the tactile experience of the rat. The negative correlation with retraction velocity shows that this parameter is a further important element of whisking strategy in determining the duration of whisker–surface contact signals. We leave to the discussion consideration of why retraction velocity is reduced in the second-contact whisk and whether increasing contact duration through this mechanism should be considered as an additional active touch strategy.
Sensory signals are generally ambiguous, sometimes entirely meaningless, in the absence of knowledge of how the sensor that generated those signals was controlled. This is particularly true of touch, where signals are obtained only through physical contact and where the trajectory of the sensor with respect to the surface codetermines, with the surface properties of the object, the nature of the signals that are obtained. Increasing evidence, both in this study and in other studies, indicates that the sensor (whisker) trajectories of the rat vibrissal system are carefully controlled, modified on the basis of recent sensory experience and in anticipation of future experience, and directed at obtaining high-quality, task-relevant information. This type of active sensing control is also apparent in human fingertip touch (Chapman 1994; Lederman and Klatzky 1993; Smith et al. 2002), suggesting that the rat whisker system can be a useful model in which to investigate "sensorimotor contingencies" (O'Regan and Noe 2001) similar to those underlying our own tactile experience of the world. In the following, our new findings in relation to active touch sensing in the rat are summarized and evaluated, beginning with the evidence that whisker spread is actively controlled, then turning to the active touch sensing strategies that appear to be used by the rat.
Control of whisker spread
Although changes in the horizontal spacing of whiskers have been previously noted (Sachdev 2002), this is the first study to have quantified the contribution of these changes to the overall observed whisking pattern. We found that 13–19% of the variance in whisker angular position data for freely moving animals, tracked from overhead, can be accounted for in terms of one summary parameter—the "spread" or angle of arc between the rostral-most and caudal-most tracked whisker. Further, together with the mean angular rotation of the whisker field these two parameters can account for ≤93% of the variance seen in the overhead view.
It is important to be clear that we regard the spread parameter as simply a descriptive measure that usefully summarizes some of the observed changes in whisking behavior. We have no direct evidence that the rat brain encodes spread as a specific control parameter (any more than it encodes amplitude, frequency, or set point as control parameters, all of which are also descriptive concepts). That the spacing between whiskers changes with time is consistent with, but does not necessarily require, active control of underlying mechanisms. Passive, rather than active, control (such as might be provided by purely mechanical properties of the vibrissal system) would imply that whisker spread should vary across the whisk cycle in a predictable and consistent manner across all types of whisk. To obtain evidence that observed changes in spread are not simply passive we needed to demonstrate variability across different whisking contexts; therefore we investigated whether anticipation of a proximal vertical surface could change the pattern of spread changes over the course of a whisk cycle. Our data demonstrate such variability. Specifically, we have shown that in the second-contact whisk, whisker spread and angular position can become decoupled, that spread is typically reduced compared with preceding whisk cycles, and most reduced following bilateral whisker–surface contacts.
Observed spread thus appears to vary across whisking contexts, but what is the source of this variation? In our analysis we tested and provided evidence against several alternative explanations, concluding that observed changes in spread were not simply the consequence of head movements, changes in other aspects of whisker control, or the result of the whiskers bending against the contacted surface. Most tellingly, perhaps, we found evidence of differences in whisker velocity indicating that the most rostral whiskers move substantially faster than the most caudal ones in precontact and first-contact whisks, but not in second-contact whisks. This result is difficult to explain other than by assuming some capacity for differential control of the whiskers themselves.
Although we have ruled out the most plausible alternatives, based on the current data we cannot directly test the hypothesis that the apparent changes in whisker spread involved control of the whisking musculature. Results from other laboratories (Berg and Kleinfeld 2003; Dorfl 1982; Hill et al. 2008; Klein and Rhoades 1985; Wineski 1985), however, show that the rat does have sufficient degrees of freedom of whisker control to effect some differential movement of either individual whiskers or whisker columns. Moreover, some divergent movement of the whiskers has been observed in animals trained to make texture discriminations (Carvell and Simons 1990) and in head-fixed animals trained to whisk for reward (Sachdev et al. 2002). That the rat has the capacity to focus its whisker field toward a target has also been suggested before in the context of the "foveal whisking" behavior described by Berg and Kleinfeld (2003). In the following we briefly compare some of the observations made in that study with our current results.
Berg and Kleinfeld (2003) used high-speed videography and electromyographic recording of the whisking musculature to investigate whisking behavior in rats that were trained to explore a maze to obtain food rewards. They described two general modes of whisking behavior that were distinguished both by their spectral properties (whisk amplitude and frequency) and by differential patterns of activation in the whisking musculature. The first mode, termed "exploratory whisking," consisted of bouts of relatively large amplitude whisks occurring at a frequency 5–15 Hz. In the second, less frequent "foveal whisking" mode, rats exhibited bouts of relatively small amplitude but high-frequency (15–25 Hz) whisking. During general maze traversal, while the animals searched for a food resource, they exhibited exploratory whisking; however, the animals shifted to the foveal mode when required to "crane their necks" across a gap to reach a food tube.
The changes in whisking control during exploration of surfaces described herein are more subtle than the marked switch from one whisking mode to another described by Berg and Kleinfeld (2003). Indeed, in the current data, the frequency and velocity of the whisker movement changed relatively little on surface contact and, instead, we saw differences in some less well studied whisking parameters such as the whisker spread and the mean retraction velocity. We consider, then, that the whisking patterns we have observed here fall within the general class of "exploratory whisking" described by Berg and Kleinfeld (2003), and we suggest that, within this mode, the rat has the capacity to modulate whisking control on a per-whisk basis, and, to some degree, per-whisker (or whisker column) basis. It is worth noting that Berg and Kleinfeld (2003) described foveal whisking as involving the vibrissae being "clustered in front of the head in a relatively dense pattern." Although this clustering is not precisely quantified it does seem consistent with what we are calling a change in whisker spread. If differential use of the whisking musculature can bring about the substantial changes in whisker movement seen following the transition to foveal whisking, it seems reasonable to suppose that similar but subtler changes in muscular control could also underpin the reduction in whisker spread we have observed when rats explore a proximal surface.
Active touch sensing in the rat
We have previously proposed (Mitchinson et al. 2007) that rat whisking uses active control strategies that serve to increase the number of whiskers contacting surfaces of interest ("maximizing contact") while controlling the amount of bending against those surfaces ("minimizing impingement"). In the current study, the reduction in whisker spread and associated changes in head tilt, found in the second-contact whisk, are consistent with both strategies because they allow an increased number of whiskers to make contact with the vertical wall without requiring that the whiskers necessarily press harder against that surface. Several other aspects of whisking and head control that might also be considered to be part of the rat's active sensing strategy are considered in the following text.
Consistent with our earlier findings (Mitchinson et al. 2007), the current study found that whisker protraction ceased rapidly following an initial contact with a surface (mean of 14.30 ms from contact to maximum protraction in the first-contact whisk). In the case of unilateral contacts, we previously found a difference between the ipsilateral (to the contact) whisker field, where protraction stopped soon after contact, and the contralateral field (where there was no contact) where it did not. From this we inferred the existence of a fast sensory feedback loop controlling the timing of whisker protraction to implement a "minimal impingement" strategy and ensure that contacts were made with a relatively "light touch." Our new data suggest that rapid cessation of protraction occurs for both unilateral and bilateral contacts and may even be quicker on the second-contact whisk (mean latency 11.25 ms). The latter finding, if supported by future studies, would imply some additional element of anticipatory control. The literature on classical conditioning shows that the latency of a reflex response, such as the rabbit eyeblink, is significantly reduced when the animal can anticipate the timing of the unconditioned stimulus (Gormezano et al. 1983). Thus similarly, the rat's ability to anticipate a forthcoming surface contact could influence the control circuitry underlying the proposed whisking sensory feedback loop, enabling it to respond more rapidly when an expected whisker deflection takes place.
An unanticipated finding of the current study was that the duration of contacts with surfaces was generally much longer in the second-contact whisk. Duration of contact was found to be best predicted by two whisking control parameters—the time from contact to maximum protraction (discussed earlier) and the retraction velocity (especially in the first half of the retraction phase). These two parameters oppose each other, but, by their interplay, it would appear that the rat could control the duration of contact, the speed at which the whisker is drawn across the surface, and the amount of bending in the whisker shaft. We think it is possible that the slower retraction during the second-contact whisk can be understood as an active touch strategy aimed at prolonging contact and thereby aiding the extraction of information about surface characteristics such as texture. Thus perhaps, the first-contact whisk could be thought of as locating the surface in space and the second as discerning more details concerning the nature of that surface. However, it is important to consider that there may be alternative explanations of reduced retraction velocity on the second-contact whisk that are not directly concerned with contact duration or with the sensory consequences of this contact. For instance, one possibility is that there might be compensatory mechanisms within the whisker pattern generator that act to reduce whisk retraction velocity following early cessation of protraction due to surface contact. Such a mechanism might conceivably operate to prevent a strong mismatch in phase between the left and right whisker fields, since it can be generally observed that the two fields have a strong tendency to return to synchronized movement following perturbation. Evaluation of this alternative will require a better understanding of the coupled motor pattern generators that generate whisker movements in the two fields and of their modulation by sensory signals. Future research on this topic should also benefit from the investigation of generative computational and robotic models of whisker geometry, musculature, and neural control systems (e.g., Hill et al. 2008; Mitchinson et al. 2006; Pearson et al. 2007).
Although going somewhat beyond the current data, we now propose the following hypothesis, consistent with the above-cited active sensing strategies that could serve as a further simplifying principle for understanding whisking control in exploring animals.
The rat appears to control its whiskers so that the spacing between the whiskers is reduced relative to the surface of interest. Thus if this is a vertical surface we see reduced spread in the overhead view (as demonstrated by our data); if a horizontal surface (e.g., the floor) we see reduced spread in the end-on view (consistent with our informal observations of video recordings but remaining to be demonstrated quantitatively). A strong version of this hypothesis would suggest that the rat also seeks to increase spacing parallel to the surface of interest, to simultaneously explore as much of that surface as possible. Thus when proceeding across the floor the whiskers appear relatively spread out when viewed from above and directed at the area of the floor around and immediately in front of the animal in its direction of motion (see, e.g., Fig. 7, left). In contrast, when investigating a vertical wall, the whiskers appear close together in the overhead view and much more widely separated in the end-on view (see, e.g., Fig. 7, right). These changes in whisker spacing are likely brought about partly through differential control of the whiskers and partly through controlled positioning of the head with respect to the surface of interest. Thus obtaining a better understanding of the interaction between head movements and whisking movements will be important to be able to fully characterize the active touch sensing strategies of the rat.
This research was supported by European Union Integrating Cognition, Emotion, and Autonomy Grant IST- 027819 and Biomimetic Technology for Vibrissal Action Touch Grant ICT-215910. R. A. Grant was funded by a doctoral training grant from the United Kingdom Engineering and Physical Sciences Research Council.
We thank P. Redgrave for scientific advice and M. Simkins, L. Hetherington, A. Ham, and M. Benn for technical support.
↵1 The online version of this article contains supplemental data.
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
- Copyright © 2009 the American Physiological Society
- Aloimonos et al. 1988.↵
- Ballard 1991.↵
- Berg and Kleinfeld 2003.↵
- Bermejo et al. 2002.↵
- Carvell and Simons 1990.↵
- Chapman 1994.↵
- Dorfl 1982.↵
- Etienne et al. 1996.↵
- Gao et al. 2001.↵
- Gibson 1962.↵
- Gormezano et al. 1983.↵
- Gustafson and Felbain-Keramidas 1977.↵
- Hartmann 2001.↵
- Hetherington et al. 2000.↵
- Hill et al. 2008.↵
- Klein and Rhoades 1985.↵
- Knutsen et al. 2008.↵
- Knutsen et al. 2005.↵
- Lederman and Klatzky 1993.↵
- Lungarella et al. 2005.↵
- Mitchinson et al. 2007.↵
- Mitchinson et al. 2006.↵
- O'Regan and Noe 2001.↵
- Pearson et al. 2007.↵
- Ritt et al. 2008.↵
- Sachdev et al. 2003.↵
- Sachdev et al. 2002.↵
- Sellien et al. 2005.↵
- Smith et al. 2002.↵
- Stuttgen et al. 2006.↵
- Towal and Hartmann 2006.↵
- Towal and Hartmann 2008.↵
- Vincent 1912.↵
- Voigts et al. 2008.↵
- Wineski 1985.↵


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Woman (42) who was trapped in vehicle following road accident awarded €518k in damages
A woman who suffered severe injuries in a road accident has been awarded some €518,000 damages by the High Court.
Adeola Ozoruchi (42), a care worker, native of Nigeria and naturalised Irish citizen since 2005, sued over the accident which happened on January 12, 2013 at Dromore West, Co Sligo, as she was driving from her then place of work, the Cheshire Home in Co Mayo, to her then home in Sligo.
Mr Justice Kevin Cross said the injuries were suffered after a motor vehicle owned by Kilcawley Building and Civil Engineering (Sligo) Ltd and Kilcawley Building and Civil Engineering Ltd, and driven by Martin Tuffy, overtook a vehicle driven by Michael Crean, Camphill, Culleens, Dromore West, and collided into Ms Ozoruchi's car.
She was trapped in her car and had to be cut out following the severe impact.
While there was an issue between the defendants due to allegations Mr Crean's vehicle was towing a trailer which was not properly lit, the case, from Ms Ozoruchi's point of view, was now one for assesssment of damages only, he said.
Ms Ozoruchi, a mother of two, was treated in Sligo Hospital and later at Tallaght Hospital for injuries including fractures to her right hip and spine and lacerations to her liver.
She underwent two operations, was on heavy pain medication, dad a depressive reaction and suffered from Post Traumatic Stress Disorder which has improved, the judge said.
As a result of the accident, she was unable to resume her work in the Cheshire Home as that involved heavy and strenuous physical labour of lifting elderly patients. While she tried to resume that work in January 2014, she was unable to, he said
She is now living in Manchester as a result of following her then husband to the UK in August 2014 because he was unable to find work here.
She works part-time as a home care worker there which involves no heavy lifting.
The judge found her a truthful witness and hard worker who had not exaggerated her injuries but rather made light of them in some respects.
There was no doubt she suffered a severe injury and the case involved a "significant cocktail" of injuries including psychiatric injuries and severe scarring to her abdomen and thigh. She still has constant pain in her right hip, a metal plate in her hip socket and her scars are permanent.
He awarded total damages of €518,786, including €275,000 for loss of earnings to date and into the future.
Online Editors


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Excelent cuality but the punch itself is HUGE. It is about the size of my two hands.
Fun and bright collection. Party and birthday themed. Excelent for celebration memories.
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excelent quality
love it, love it soooo cute
beautifull and good quality
would keep on buying it.


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Discourse in Late Modernity : Rethinking Critical Discourse Analysis Paperback
by Lilie Chouliaraki, Norman Fairclough
Part of the Critical Discourse Analysis series
Discourse in Late Modernity sets out to show that critical discourse analysis is strongly positioned to address empirical research and theory-building across the social sciences, particularly research and theory on the semiotic/linguistic aspects of the social world. It situates critical discourse analysis as a form of critical social research in relation to diverse theories from the philosophy of science to social theory and from political science to sociology and linguistics. First, the authors clarify the ontological and epistemological assumptions of critical discourse analysis - its view of what the social world consists of and how to study it - and, in so doing, point to the connections between critical discourse analysis and critical social scientific research more generally. Secondly, they relate critical discourse analysis to social theory, by creating a research agenda in contemporary social life on the basis of narratives of late modernity, particularly those of Giddens, Habermas, and Harvey as well as feminist and postmodernist approaches. Thirdly, they show the relevance of sociological work in the analysis of discursive aspects of social life, drawing on the work of Bourdieu and Bernstein to theorise the dialectic of social reproduction and change, and on post-structuralist, post-colonial and feminist work to theorise the dialectic of complexity and homogenisation in contemporary societies. Finally, they discuss the relationship between systemic-functional linguistics and critical discourse analysis, showing how the analytical strength of each can benefit from the other. * Sets out a new and distinctive theoretical grounding and research agenda for critical discourse analysis * Interdisciplinary in scope * Draws on a broad range of theories and approaches
- Format: Paperback
- Pages: 176 pages
- Publisher: Edinburgh University Press
- Publication Date: 14/09/1999
- Category: Semantics
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Long time, no see. I've been dealing with computer issues recently and didn't have my laptop. My hard drive crashed… But I'm not going to use that as an excuse. I could have used my boyfriend's laptop, but I just haven't been in my element lately. However, that's going to change RIGHT. THIS. MINUTE.
I intend on getting back into my weekly posting schedule, so expect more outfit posts to come your way in the near future!! For now, I am going to share my wardrobe wishlist. It's that time of year, with Christmas and my birthday in just a little over a week so who knows? Maybe some of these beauties will be coming my way.


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KeraLink International Resources
Vision Share, Inc. and KeraLink International Strategic Collaboration
Two eye banking leaders announced their new cooperative tissue sharing agreement designed to significantly increase the availability of transplantable ocular tissue grafts to surgeons worldwide, during the Eye Bank Association of America's 56th Annual Meeting in Salt Lake City, Utah.
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08-26-04, 13:10 #1Registered User
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- Aug 2004
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- 3
Unanswered: Foreign keys disappeared from database
We have a couple of platforms that serve the QA and DEV environments for testing our growing e-learning product that I maintain.
The tables are all InnoDB and I run nightly and weekly maintenance tasks that perform Check Tables, Defrag Tables, Flush Tables, daily backup and a few more.
Two days ago the foreign keys on two of the platforms simply vanished. Thus, the backup from the day before HAD the foreign keys while the next day did not.
Trying to run my foreign key script to build them again did not run on one of the platform and I dropped the database and recreated it from the backup that had the foreign key and now all is back to normal.
The fact that it happened though is still bugging me and reviewing Heikki Tuuri responses to some problems I saw a bug associated with the ALTER TABLE query that used to be a bug and that used to drop the FK without re-creating them.
The Defrag tables script is made of the ALTER TABLE query and I wonder whether it might have been related to the problem. Also, on the day of the FK disappearance we had serious network problems. I do not know whether script was run during the network problems and whether it has anything to do with the problem.
Until two days ago the maintenance scripts have been running perfectly well without any problem.
Will greatly appreciate any feedback especially from Heikki.
Thank you.
Interactive Constructs, Inc.
Medford, MA


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MUST BE ADDED TO ANY NEW/Mobile THEMES ---------->
MUST BE ADDED TO ANY NEW/Mobile THEMES ---------->
Are you having a good summer? Make sure that your best friend is, too! Whether your plans include road trips or barbecues in the backyard, follow these tips to ensure that your pet is safe and happy.
Storms and other anxiety-inducing events
No matter where your summer plans take you, make sure that your dog has access to shade and water at all times. Enjoy!
Imagine teaching your dog to put his hind feet—just his hind feet—on a mat. Or, imagine teaching your cat to give a high-five. What if you could teach your dog to use his nose to ring a bell to go outside?
These fun and useful behaviors are all examples of targeting a body part to a specific object. Training your pet to touch a target is not only a fun game to play, but it is easy to teach and can extend to even more complicated behaviors or to tools in administering veterinary care.
Targets can be almost anything. Use a kitchen rug as a settle mat for your dog; the dog targets his whole body onto the kitchen rug. Your cat can sit on a drink coaster while you fix dinner; as long as her feet are on the coaster, she can't jump on the counter and pester you. Teach your dog to ring a bell, and you have a doggie doorbell for him to use when he has to go to the bathroom outside. Targeting the dog's nose to the bell is the easiest way to avoid damage to the bell. Teach your horse to target a hoof to a bucket, and you have made soaking the hoof a lot easier (for you and the horse!).
It's easiest to begin by teaching an animal to touch its nose to a target held close to the nose. Use just about anything as a target: a sticky note, a pencil, or even your hand. These targets all work well for smaller animals like dogs and cats. For larger animals, a larger target may be easier. A tennis ball on a dowel rod can be used as an inexpensive target for horse training.
Here's how to get started using a target with your pet:
After you have taught your animal to touch a target, move to a more advanced targeting skill: following a target. Think of how easy it would be to move your pet from one location to another (loading your dog into a car, for example) if all you have to do is place a target in front of your pet's face and then move the target to where you'd like the animal to go!
Other uses for targeting include getting an animal onto the scale at the veterinary hospital, moving your pet off the sofa so you can have a seat, and moving your dog away from another dog walking down the path. You can also use a target to teach your dog to move away from you. Stick the target on the wall and the dog will learn to move away from you in order to earn a click and treat.
Here's how to teach your pet to follow a target:
Using the target stick makes teaching tricks easier, too! Imagine how easy it would be to teach your dog to turn the lights off or to close the refrigerator door for you. You can accomplish this, and realize other dreams, all by using a target stick!
The targeting behavior comes in handy if you would like your dog to walk on a loose lead. Simply present the target next to your leg; click and treat the dog for walking at your side (i.e., for following the target). Targeting is a great tool for horse owners, as well. Using a tennis ball on a dowel makes loading your horse into a trailer a breeze. There are so many practical and entertaining applications of targeting!
Whatever needs targeting can fill for you and your animal, remember to work toward your goals slowly and positively. Steady success makes training so much more enjoyable for all!
Laurie Luck, KPA CTP, and a Karen Pryor Academy faculty member, is the founder of Smart Dog University. She has been involved with many pet dog trainer certification initiatives, all based on humane training practices and the latest scientific knowledge. Laurie also participates in service dog training, and she and her Tango are a pet-therapy team. Through her work with dogs and owners, Laurie has developed many happy canine and human friendships.
If you are a trainer, when you see a dog on a leash your attention may go to gait, ease of movement, equipment worn, and the handler's use of the equipment. It is deeply satisfying to see an animal's comfortable stride, with a handler enabling that stride. But often what you see is less than wonderful: a roached back, constant tension on the leash, leaning-away from the handler, blocking of the animal's joints, and more. The wrong choice of equipment or a bad fit can be responsible for these problems. Careful equipment choices and equipment fit, especially the fit of a harness, can eliminate these issues.
Read on for suggestions for making informed decisions about equipment and fit. What your dog wears for walks is your personal decision, but the information that follows will help you decide what is best for your dog and for you.
Some concerns about collars
Many excellent trainers leash-walk with the leash attached only to the dog's collar. They do this for a variety of reasons, including:
Here are some of my concerns with collars:
You don't have to have pulling in order to create pressure or injure your dog via the collar. It just takes one instance of accidentally stepping on the leash. Try this exercise: Wrap your hands and fingers around your neck with your thumbs at the front and center of your neck. Now push in with your thumbs and try to breathe normally. It's not comfortable for humans, so why would we think pressure on the neck is comfortable for dogs?
Well-known veterinarian Jean Dodds has also been concerned about collars, and answered a question on her blog about collars damaging the thyroid.
"This is an important question that we're all trying to pay more attention to, because the thyroid and salivary glands are superficially located just under the skin in the upper part of the neck. The thyroid gland is a butterfly-shaped organ just in front of the larynx and trachea, and the mandibular salivary glands are found on the side of the face just below the ears. Thus, they can be easily injured by trauma and sudden pressure forces (like could occur from the slip ring and chain of metal collar, and a metal prong or hard braided leather collar)."
I no longer use collars, even for tags; there are identification (ID) tags for harnesses that stay put and don't get caught on things. I recognize that there are some especially soft collars and collars with lovely designs that might be used for ID tags, fashion, or connecting a leash to. Of course, prong, choke, and electronic (remote) collars can harm your dog and, therefore, are not recommended at all.
Leash-walking harnesses
Like collars, ill-suited and ill-fitted harnesses can cause harm, both physical and behavioral. Harnesses that rub under the legs or restrict movement, or otherwise make your dog uncomfortable, should be ruled out. Some dogs are uncomfortable with anything touching their ears or slipping over their heads. While some people want padded or fleece harnesses, I think this is because they have experienced some of the many harnesses that rub dogs and aren't soft enough where the harness is in contact with the dog's fur or skin. A soft nylon harness is perfectly comfortable as long as there are no rough or cut edges that can rub against the dog.
Harness fit
Look for a harness with both front and back rings to connect to the leash. I often teach a handler to attach a leash to both the front and back rings while handler and dog are learning to partner on leash. This requires a leash with two snaps, not two leashes, and can be done with one hand easily. Once the team communicates well while walking (no pulling matches are occurring), the handler can move the leash to the front or back ring only.
I prefer to use the ring that is between the withers rather than the front chest ring. Given that dogs often walk in front of us, we can too easily pull them off balance if we are behind them and using only the front ring.
Measuring your dog's girth for harness fit, be sure to measure where you'd like the harness to fit (assuming you are using a fully-adjustable harness like the Balance Harness). Once you get the harness, use your own eyes, hands, and the dog's reaction to the harness to tell if it is a match. The dog should be completely comfortable in the harness.
If you are using a harness that slips over the head, once the neck strap is adjusted to fit over the dog's head you will get an idea of how much the girth strap needs to be adjusted. Remove the harness and adjust it. The chest and top straps (Balance Harness only) can be adjusted last. By adjusting these straps, you can decide where the girth strap fits best on your dog's rib cage. I usually adjust a harness so that this strap is two to three inches behind the front legs and elbows.
Teaching your dog to love his harness.
Teaching your dog to get dressed
Take the time to introduce the harness so that it's a positive experience for the dog. Invite your dog to put her head through the neck opening on her own and reinforce her for doing so. You can use a nose-to-hand "touch" cue that starts with your hand near the opening of the harness. Gradually move your hand so that to touch it she has to put her head through the harness. This should be easy for your dog and reinforced often (refer to detailed steps below). Take your time before using the harness as a cue. Hold off until it predicts that good things are going to happen. It'll be worth it in the long run. If your dog is sound-sensitive, gradually get her used to the sound of the neck buckle closing.
Follow these steps to teach your dog to slip her head into a harness. You may need to repeat the steps several times, over several training sessions, before actually putting the harness on the dog. You are teaching the dog that the harness predicts good things will happen.
Before you head out…
Selecting leash-walking equipment means making an important investment in your dog's health, performance, and behavior. Take the time to make the choice that "fits" you and your dog perfectly.
What is also important, and closely related to leash-walking equipment, is training loose-leash walking. This kind of training pays off big in building your relationship with your dog and cementing an activity that you can do together with ease and in sync. With your equipment set, you're ready to head out. Before you do, read How to Teach Loose-Leash Walking and watch the DVD Tellington TTouch Techniques: Walking in Balance With Your Dog.
Panda, the guide miniature horse trained by ClickerExpo faculty member Alexandra Kurland and the beloved service animal and companion of Ann Edie, had a tough 2016. Like many of us, Panda and Ann are looking ahead to brighter skies in 2017—and we all can help.
Ann, who is blind, has enjoyed the assistance and friendship of Panda since 2003! Panda not only helps Ann "travel smoothly and efficiently around my community," but she transmits joy to those around her, demonstrating her intelligence and good humor daily. As Karen Pryor wrote in The Panda Game:
"KPCT was fortunate to have Ann Edie and Panda as honored guests at ClickerExpo Newport in 2006. Everyone enjoyed meeting this distinguished pair. We were awed by Panda's calmness as she guided Ann during the day, through crowds and halls and past all sorts of dogs (some of which were distinctly upset at having a horse among them)."
Since May, 2016, Panda has been ill. While Panda is at home now and is continuing to recover, the multiple hospital admissions, tests, and medications she has needed have resulted in very high vet bills for Panda's family.
Alexandra Kurland has created a YouCaring fundraising page for Panda and Ann, hoping that kind and caring friends and strangers might contribute to paying down these medical bills. If you are so inclined, please visit the page to make a contribution (of any amount), read updates, and post good wishes for Panda.
To show support for Panda and Ann, throughout the month of January Karen Pryor Clicker Training will donate 20% of the proceeds from the sales of horse training kits, books, and DVDs (authored by Alexandra Kurland), treats, and apparel to the Panda fund! Shop now.
Some dogs are born to tug. Although I wasn't present for his birth, I did meet Blink, my border collie, when he was very young (about 3 weeks old). I was lucky enough to visit his litter each week until I brought Blink home at age 8 weeks. I can attest to this—from the time he and his siblings were able to grasp something in their tiny mouths and hold on to it, they were tuggers. Fierce, enthusiastic, tuggers. They would tug until they dropped from exhaustion, falling asleep mid-tug with some poor, unsuspecting, braided-rope monkey toy hanging out of their mouths with its stuffed head half torn off. (True story).
Having had two Labs that were all about the food and "meh" about tugging, I thought this was just about the coolest thing ever! These baby puppies were grrring and tugging with all their might and seemed to really enjoy the game.
Given that, tug became a very powerful reinforcer early on Blink's life. In fact, tugging was used to reinforce desirable behavior long before the pups ever left their breeder. I had such a huge head start using tug as a reinforcer in training that it felt like cheating! By the time I brought Blink home, not only did he have a reinforcement history of tugging, he had a reinforcement history of tugging with ME.
I capitalized on that reinforcement history right away. Unlike food (which Blink would accept politely, if I was lucky), he was rabid about tug. So rabid that he once lost three puppy teeth in the span of an hour-long group class and kept right on tugging through it all. Blink simply could not get enough of the game. I would have been foolish not to use that passion to my advantage in his training. I used tug as his main reinforcer for every single new behavior I taught him. "Wait." Click/tug. "Sit." Click/tug. "Lie down." Click/tug. And on it went, until we built up a basic behavioral repertoire successfully, solely using clicker training, but almost never using food as a reinforcer.
Blink also loves to chase toys like balls, Frisbees and ring toys. Later on, when I wanted to add some distance to Blink's behaviors, I began using thrown toys as reinforcers. For instance, if Blink was 20-30 feet away, and it wasn't possible to tug with him, I would click and reinforce with a thrown toy.
To this day, tug remains 7-year-old Blink's main reinforcer. I do use food sometimes, but almost everything the dog knows was taught with tug or a thrown toy. "Give me a hug." Click/tug. "Hold still while I trim a nail." Click/throw a ball. "Do a dog-sport demo with me in front of a crowd of people and dogs." Click/tug.
Although it works great with Blink, using toys in place of food as reinforcers isn't for every dog. For example, this would have been a terrible training plan for my Labs, unless I took the time to condition toys as secondary reinforcers for them. But, if you have a dog that loves tug or toys more than food (not to be "breedest," but herding dogs often fit this description!), try using those things as reinforcers.
You can find an assortment of tug toys here, including the Follow Me fleece braided tug that Blink is enjoying in the video.
If you're interested in learning more about adding toys, tug, natural, and novel reinforcers to your reinforcement strategy, and improving your own reinforcement skills, Ken Ramirez has authored an entire online course on this very subject! Check out the Smart Reinforcement course.
Karen Pryor Clicker Training's Terry Ryan Treat Pouch was named "best treat pouch/bait bag" in the August 2016 issue of The Whole Dog Journal (WDJ). Nancy Kerns, Editor in Chief of WDJ, tested and rated a variety of treat pouches as she walked and trained her own dogs. An admitted "treat-bag junkie," Nancy experiments with all of the reasonably priced bags she finds, and has clear criteria on what makes a bag great.
The WDJ article discusses first the basic features of a working treat pouch, including preferred size, open-and-close method, quality, ease of care, and "extras." Although she herself does not like bells and whistles, Nancy does mention some design additions that might appeal to other trainers (space for poop bags, extra loops for attaching keys, etc., space for personal items).
What leads Nancy Kerns to declare the Terry Ryan Treat Pouch her "absolute favorite" is its simplicity—and quality. From the pouch's belt attachment to the French-spring hinge mechanism for easy access, from the space for a basic phone to the squared base of the bag that allows it to stand alone on a flat surface, Nancy praises the Terry Ryan Treat Pouch as an essential tool. While the WDJ test results article describes two pouches that are runners-up, and lists other bags that did not make the cut, only the Karen Pryor Clicker Training product was described as "Everything we need, nothing we don't!"
The FitPAWS K9FITbone is a very versatile piece of balance equipment. The lateral movement the K9FITbone offers encourages your dog to engage the abdominal muscles, the muscles along the spine (core and trunk muscles), and the supporting muscles around the hips and shoulders that are used for stability and support good posture. Here are 10 great reasons to use the K9FITbone at home or during a class:
Have you ever wanted to reward your dog for a job well done, but didn't have food treats with you? Consider playing with your dog to reinforce good behavior! Using play as a reinforcer is convenient – it doesn't require anything but you and your dog. It adds variety to your training routine, and also helps strengthen your relationship. Here, Karen Pryor Faculty Member Laurie Luck offers these suggestions for finding your dog's play preferences.
Finding and fostering play preferences
Some dogs are natural retrievers—fetch is their game of choice. Other dogs like to chase or be chased. Still other dogs like physical play—roughhousing is fun for them. To determine what play your dog enjoys naturally, watch your dog when he's with other dogs. Does he like to body slam and wrestle with his doggie friends? Chances are he might like to do the same with you. Does he chase other dogs? Does he like it when other dogs chase him? See if you can engage your dog in these same kinds of games.
Maybe your dog loves the water? Find a water-worthy toy and get him involved in play in his element. Does your dog go crazy for squeaky toys? Buy several toys with different squeakers (there are toys that "squeak" grunts!) and see which type of squeak your dog likes the most.
If your dog doesn't seem to like any particular game or toy, there are toys with little pockets you can put food into. Lure your dog into interacting with a toy to jumpstart play.
When you know your dog's play preferences, next comes the fun part: shopping for toys! There are so many toys on the market, you are sure to find one that fits your dog's preferences. If your dog likes to chase things, take a look at toys like the Kong Ball or Planet Dog Fetch Ball.
If your dog loves the water, look for bright, floating toys that you can toss into the surf such as the Gripple and the Bobb. Or, for fun both in and out of the water, try a ring toy such as the LED Floating Ring Mini. If your dog is just learning to fetch, attach those toys to a River Rope, in case your dog decides not to fetch the toy. With a River Rope you can pull the toy back in easily, without having to go into the water yourself. The rope also keeps the toy from going downstream or out with the tide!
If squeaking is what your dog is after, your options are almost limitless. Check out the Kong toys that have squeakers built in (my dogs' favorites!), like the Kong Air Dog SqueakAir Buoy. If your dog likes to chase things and enjoys squeakers, toys like the Kong Jumbler Ball can be very enticing!
Top Choice = You
Don't forget that the opportunity to play with you can be the most rewarding activity of all! Run from your dog, and see if he follows you. Give chase after your dog; my dogs seem to enjoy this game most of all. That one is a win-win choice—we're having fun together and we're both getting exercise!
Working play into your daily interactions with your dog is valuable for a myriad of reasons. First of all, it's impossible to measure the fun! Fun is an effective reinforcer in training, too, whether you are training basic manners or more advanced skills and tricks. Don't forget that amazing side effect of playing with your dog—your relationship with your dog gets better and better.
Now get out there and play with your dog!
Everyone loves the holidays, but changes in routine and the comings and goings of visitors can create stress for many pets. At times like these, interactive treat toys such as Kongs can be particularly useful. Karen Pryor Academy and ClickerExpo faculty member Laurie Luck explains how to pre-stuff Kongs so that you always have a terrific, but easy, way to keep the holiday peace!
I use Kongs to buy time if I'm working on a project. Busy dogs are good dogs! Offering Kongs is also a preventive measure to avoid separation anxiety. Every dog in my house gets a stuffed, frozen Kong as I'm walking out the door. They don't stress about my departure or my absence. In fact, the dogs love to see me leave!
When you're stuffing Kongs for four dogs, as I do, it's helpful to pre-stuff a bunch at a time and freeze them—the treats will be ready whenever you need them! Start with a basket of empty (and clean) Kongs. I run the Kongs through the dishwasher about once a month (top rack, no heat) just to clean all the goop off. I do this for myself only—the dogs do not mind the goop at all!
I'll use peanut butter as the stuffing example, but you can put almost anything your dog likes in the Kong. Some ideas include cream cheese, canned pumpkin, leftover mashed potatoes, plain yogurt, ricotta cheese, cottage cheese—pretty much anything that's gooey. If you really want to keep your dog busy, toss in a few kibbles and shake the Kong so that the kibbles stick to the sides. Or, add apple or banana pieces to the Kong (do not add grapes or raisins, as they are toxic to dogs).
With the filling and the Kongs ready, slide a knife into your filling and spread the filling all over the inside of the Kong. With the peanut butter on the knife, just run the knife along the inside of the Kong. I try to distribute the peanut butter evenly, but only because I'm a control freak and like to have everything just so. The dogs don't care how the peanut butter is distributed, as long as there is peanut butter in the Kong!
After the Kong is stuffed, I drop it into a big plastic bag. Why? I put stuffed Kongs in the freezer. Frozen peanut butter takes longer for the dogs to extract, so it keeps the dogs occupied for longer periods of time. The plastic bag also keeps all the Kongs together so I can find them easily. Finally, placing Kongs safely in a bag keeps my freezer a little cleaner.
Pop the entire bag of peanut-butter-filled Kongs into the freezer and allow them to freeze. Now you are ready for the week (or the holidays) ahead!


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Keepy Uppy 2010 Rated Stars Play Keepy Uppy with a normal football or The Jabulani! Sports - Soccer MAXOTONIC 2 Rated Stars A sequel to MAXOTONIC, with better graphics and more. Shooter - Horizontal Flight Drawin' Fun Rated Stars Draw then Play with your Favourite Character, Including Agnry Faic and The NG Tank! Action - Other Solo Racer Rated Stars Race Solo and Beat Your Best Lap Time in this 10 Lap Solo Racing Game. Sports - Racing MAX0T0NIC Rated Stars Help Max save MAXOTONIC from the Evil Aliens in their UFOs. Shooter - Horizontal Flight


text: Home > Sports Arum still hopeful on Donaire-Mares ABS-CBN News Posted at Jan 18 2013 06:22 PM | Updated as of Jan 19 2013 06:13 AM Share Save Facebook Twitter GPlus LinkedIn MANILA – Top Rank CEO Bob Arum remains optimistic he can still arrange a unification title clash between emerging boxing star Nonito Donaire Jr. and unbeaten Mexican champion Abner Mares. Arum is hopeful he can still work out the Donaire-Mares bout for an April fight date. "We'd like to get that fight done. I know that I've been contacted by Mares' manager, Frank Espinoza, and he's trying to work out a deal with Golden Boy to free up Mares," the boxing promoter told Lem Satterfield of RingTV. Mares, the World Boxing Council (WBC) super bantamweight champion, fights under Golden Boy Promotions (GBP), which competes against Arum's Top Rank Inc. Top Rank owns the exclusive promotional rights of Donaire, the World Boxing Organization (WBO) super bantam king. Arum refuses to co-promote the fight with Golden Boy but is willing to shell out a fee to pay for Mares' services. "We will see [Donaire] again hopefully in April. If we can free up Mares, that would be a good fight. If we can't, then [Donaire will] probably fight Guillermo] Rigondeaux," said Arum. Arum, however, seems to agree that Donaire-Mares is more lucrative, citing Rigondeaux's lack of marketability. "The only way to make Rigondeaux a household name is if Fidel [Castro] came over and co-promoted with me." Share Save Facebook Share on Twitter GPlus LinkedIn Read More: boxing Bob Arum Nonito Donaire Jr. abner mares Guillermo Rigondeaux /entertainment/11/25/17/look-anne-curtis-wedding-photo-lands-on-nz-papers-front-page/video/business/11/25/17/senate-retains-20-tax-on-cosmetic-surgery-in-tax-reform-bill/video/life/11/25/17/tingnan-gimik-ng-isang-mall-sa-ortigas-para-sa-kapaskuhan/video/news/11/25/17/tugade-denies-rift-among-dotr-officials/video/business/11/25/17/ayala-group-members-lead-ph-shares-rebound


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Falling Card Suits
The file is really small, only two kb, and is easy to manage! More importantly; there�s a lot to customize! You can set the: * Dimensions of the field on which you want to display falling card suits. * Minimum and maximum object size * Minimum and maximum alpha level of the objects * Minimum and maximum movement speed * Minimum and maximum rotation speed * Amount of objects falling at once * The objects that are falling! Simply change the shapes inside the movieclips. All actionscript is commented, so it�s very easy to change all of the above. Obviously, the background can be changed easily as well � simply paste an image or draw a gradient underneath the movieclip! If want only a part of your stage to display the falling card suits � no problem! A mask is automatically created that will make sure no suits are shown outside the width and height you define!Visit publisher site: Falling Card Suits
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- Aug 26, 2010
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