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This paper presents a three-dimensional (3D) method for segmenting corpus callosum in normal subjects and brain cancer patients with glioblastoma.
Nineteen patients with histologically confirmed treatment naïve glioblastoma and eleven normal control subjects underwent DTI on a 3T scanner. Based on the information inherent in diffusion tensors, a similarity measure was proposed and used in the proposed algorithm. In this algorithm, diffusion pattern of corpus callosum was used as prior information. Subsequently, corpus callosum was automatically divided into Witelson subdivisions. We simulated the potential rotation of corpus callosum under tumor pressure and studied the reproducibility of the proposed segmentation method in such cases.
Dice coefficients, estimated to compare automatic and manual segmentation results for Witelson subdivisions, ranged from 94% to 98% for control subjects and from 81% to 95% for tumor patients, illustrating closeness of automatic and manual segmentations. Studying the effect of corpus callosum rotation by different Euler angles showed that although segmentation results were more sensitive to azimuth and elevation than skew, rotations caused by brain tumors do not have major effects on the segmentation results.
The proposed method and similarity measure segment corpus callosum by propagating a hyper-surface inside the structure (resulting in high sensitivity), without penetrating into neighboring fiber bundles (resulting in high specificity).
Keywords:Corpus callosum; Fiber bundle segmentation; Level-set; Glioblastoma; Diffusion tensor imaging
Corpus callosum is the largest inter-hemispheric fiber bundle in the human brain [1,2]. Most of the fibers interconnect homologue cortical areas in roughly mirror image sites but a large number of the fibers have heterotypic connections ending in asymmetrical areas [3]. Previous studies have mainly investigated effects of various pathologies on the corpus callosum [4-7]. However, a fully automated, fast, and accurate method for segmenting corpus callosum without penetrating into irrelevant neighboring structures, using data acquired in routine clinical protocols, is still lacking.
Previously, image processing methods have been proposed for segmenting corpus callosum in anatomical magnetic resonance images (MRI) [8-10]. These methods rely on intensity information of two-dimensional images and their results may need pruning. Recently, attention has been oriented towards diffusion tensor imaging (DTI) to segment white matter tracts of the brain [11,12]. Although the tensor model fails to describe higher order anisotropies in heterogeneous areas where more than one fiber population exists, it is practically useful for extracting major white matter tracts, particularly the ones with predominant diffusivity pattern such as corpus callosum. When using DTI data, the fiber bundles can be extracted by: a) clustering of fibers resulting from tractography into fiber bundles [13-19]; or b) segmenting fiber bundles via hyper-surface propagation based on local properties of diffusion tensor, diffusion signal, or orientation distribution function (ODF) [20-27]. Since clustering methods rely on the tractography results, they do not work properly if the tractography results are inaccurate. On the other hand, segmentation methods based on hyper-surface propagation do not use the tractography results and are thus more robust to noise.
In a region-based segmentation framework, a similarity measure between successive tensors is typically used. Some of the hyper-surface propagating methods in the literature concentrated on scalar quantities derived from the tensor data which do not reflect complete tensor information [20]. Other methods benefit from the entire information contained in the DTI data [21-30]. Wang and Vemuri [22] proposed a statistical level-set segmentation method. However, the tensors derived in this framework are not necessarily positive semi-definite, leading to inappropriate results especially when consecutive tensors are much different. Metrics like Kullback-Leibler divergence and J-divergence [23,24] have also been proposed. One of the most promising methods is introduced by Jonasson et al. [25]. They defined a new similarity measure called normalized tensor scalar product (NTSP). Comparing NTSP with other similarity measures, they demonstrated superiority of their proposed measure. To segment brain structures like thalamic nuclei, they modified their framework to favor the propagation of multiple hyper surfaces without overlapping [26]. Lenglet et al. [27] defined a dissimilarity measure and statistics between tensors based on the Riemannian distances. Although improving the segmentation results, this approach is computationally expensive. Defining a Log-Euclidean distance, another metric was defined by Arsigny et al. [28] which has lower computational burden. Weldeselassie and Hamarneh [29] used their proposed similarity measure in an energy minimization framework. Awate et al. [30] used the similarity measure in a Markov random field framework.
In terms of quantitative evaluation of diffusion parameters, previous studies have compared DTI-based indices in normal appearing white matter and corpus callosum in multiple sclerosis [4], stroke [5], schizophrenia [6], and Huntington's [7] and also studied the DTI methods to assess corpus callosum regions across the human lifespan [31]. For segmenting corpus callosum and its subdivisions in these studies, however, two-dimensional (2D) methods were applied and DTI-based indices compared in the mid-sagittal plane. However, without recruiting a three dimensional (3D) method to segment the whole corpus callosum and its subdivisions, the extracted quantities may be inaccurate.
Since the tensor model is not capable of describing heterogeneous diffusion behavior in the crossing fiber bundles, some studies used High Angular Resolution Diffusion Imaging (HARDI) data to segment specific bundles [32-38]. However, the HARDI data is not widely acquired in clinical centers and hence, the tensor-based methods are still of more practical use in clinical research.
In this manuscript, we present a 3D method to segment corpus callosum. Based on tensor and anisotropy values of neighboring voxels, a similarity measure is proposed and used as a speed function in the proposed level-set method. In this method, the principal diffusion direction (PDD) and prior information about the diffusivity pattern in corpus callosum are used to avoid inclusion of neighboring fiber bundles. Then, the Witelson subdivisions of corpus callosum are automatically identified [39]. The idea of using diffusivity pattern in corpus callosum has been used by Lee et al. [40]. However, they performed a 2D segmentation on the mid-sagittal plane. Moreover, since their method uses the left-right component of PDD to delineate corpus callosum boundaries, it is not applicable in more lateral sagittal planes, where corpus callosum connects to minor and major forceps and considerable anterior-posterior component of PDD exists.
The proposed segmentation method can be identically used for segmenting corpus callosum of control subjects as well as patients with glioblastoma. However, since we use the geometric information of the diffusivity pattern in corpus callosum and the glioblastoma tumor may change the original shape and diffusivity pattern of corpus callosum, we validate the reproducibility of the proposed method through realistic simulations of corpus callosum rotations under glioblastoma tumor pressure. We study the effects of rotation by different Euler angles (azimuth, elevation and skew) quantitatively and demonstrate that even in extreme cases with large rotations, brain tumors do not have major effects on the segmentation results generated by our proposed method. We apply the method to the DTI data of normal subjects and brain cancer patients with glioblastoma and show its superiority to some of the previously published methods in the literature.
Patient population
This study is approved by the institutional review board and is compliant with the Health Insurance Portability and Accountability Act (HIPAA). Between February 2006 and December 2008, 19 patients (8 males, 11 females; mean age 60.7 years) with treatment naïve glioblastoma underwent MRI with DTI using a 3 T scanner at our institution. Based on anatomical MRI findings, the patients were divided into two groups: Group 1 including patients with tumors not infiltrating corpus callosum (n = 12); and Group 2 including patients with tumors infiltrating corpus callosum (n = 7). For the control group, 11 patients (5 males, 6 females; mean age 48 years) who underwent brain MRI for nonspecific headache or single idiopathic seizure with normal MRI were included.
Magnetic resonance imaging protocol
All the patients underwent both conventional MRI and DTI on a 3 T scanner (Excite HD, GE Medical Systems, Milwaukee, WI) using an 8-channel head coil. Diffusion weighted images (DWIs) were acquired in 25 diffusion gradient directions. The reconstructed DWIs have intra-slice resolution of 256 × 256 with voxel size of 0.98 × 0.98 × 2.5 mm. To have the same step size in each direction for the front propagation in the level-set method and to avoid extensive computation, we interpolated the data into 128 × 128 grid with cubical, 1.9 × 1.9 × 1.9 mm voxels.
Level-set approach
We use a level-set method that takes into account several properties when formulating the segmentation problem [41,42]. The method smoothes the propagating hyper-surface automatically and leads to a regularized segmentation. Among the advantages of the method, its property of generalizing from 2D to 3D and higher dimensions and automatic splitting and merging of the surfaces are notable. In addition, it simplifies calculation of geometric quantities needed in the proposed method such as normal to surface and curvature.
For bundle segmentation in areas with high level of similarity in diffusion, the hyper-surface needs to grow in the direction normal to the surface. Moreover, the resulting fiber bundles must be smooth. Consequently, we use a level-set whose growing hyper-surface is the zero level-set of the following function which is a reduced form of the Hamilton-Jacobi partial differential equation:
where r ∈ ℜn is the state space, φ: ℜn × ℜ → ℜ is the level-set function, Dt φ is the partial derivative of φ with respect to the time variable t, ∇φ = Dr φ is the gradient of φ with respect to the state space variables, and F(r, t) is the speed in the direction normal to the surface, extracted from the spherical harmonic coefficients of the neighboring voxels. The sign ∥·∥ stands for the magnitude operator. The curvature κ(r, t) is used to fulfill the smoothness constraint. To calculate the first order spatial partial derivative ∇φ(r, t), we use the 5th order of the upwind method [41].
Corpus callosum segmentation
Corpus callosum is a commissural fiber bundle with a specific diffusion pattern which can be coded as prior knowledge in the segmentation framework. Using this information, we prevent the hyper-surface from propagating into adjacent white matter structures such as cingulum, tapetum, minor and major forceps, and tracts of the corona radiata. Although dissimilarity among tensors helps in this case, smooth and gradual transition in shape and direction of the DTI tensors from corpus callosum to minor and major forceps makes the segmentation difficult.
We define a similarity measure between every voxel on the propagating hyper-surface and its neighbors in the propagation direction, based on tensor and anisotropy values. This similarity measure is used as the speed term F(r, t) in Equation (1). The hyper-surface propagation in each step depends only on the speed function of the boundary voxels. This speed function term moves the hyper-surface to fill the whole fiber bundle, while the regularizing curvature term in Equation (1) is in charge of smoothing corpus callosum without changing its real structure.
Using the fact that the diffusivity in corpus callosum is perpendicular to the mid-sagittal plane of the brain, we consider a threshold (PDDx Threshold) for the x-component (left-right component) of the PDD (PDDx(r)) for propagating the front only inside the corpus callosum. The x-component of the PDD is large throughout the structure body. However, corpus callosum fibers project to the cortical area at its genu and splenium, where the x-component of PDD is not large anymore. Fortunately, these fibers are considered as different fiber tracts of minor and major forceps, and most of studies investigating the different diffusion indices within the corpus callosum, exclude the minor and major forceps from that.
In the proposed algorithm, we consider two more thresholds on collinearity of the PDD vectors (Collinearity_Threshold) and similarity of fractional anisotropy (FA) values (FA_Threshold) in the neighboring voxels.
The proposed segmentation steps are as follows:
1. Select the initial seeds in corpus callosum in mid-sagittal plane manually.
2. Initiate the hyper-surface as the congregation of small spheres around the seed points.
3. Do until convergence
• For each point r on the hyper-surface at step t:
a) Calculate the normal direction to the surface.
b) Calculate the 26-neighborhood and keep the neighbors nr for r, which are collinear with the normal, with respect to the r.
c) If PDD(r). PDD(nr) > Collinearity_Threshold & FA (nr) > FA_Threshold & PDDx (r) > PDDx_Threshold
• Threshold F(r, t) with F _ Threshold to diminish the effect of negligible speeds.
• Use the resultant speed in the level-set framework.
4. Extract the zero level-set as the segmented corpus callosum.
In Equation (2), tr(.) is the matrix trace and D(r) is the tensor at point r.
After segmenting corpus callosum, Witelson subdivisions of corpus callosum are automatically extracted [39]. First, the critical point between genu and rostrum of corpus callosum is calculated, where the curvature of the structure boundary in mid-sagittal plane changes. Then, the segmented corpus callosum is automatically subdivided into Witelson subdivisions in the mid-sagittal plane: rostrum, genu, rostral body, anterior mid-body, posterior mid-body, isthmus and splenium [39]. Moreover, the user can visualize and confirm the calculated mid-sagittal plane and the critical joining point between genu and rostrum. The critical point can be selected manually if close supervision is preferred or needed.
Segmentation using proposed method
We implemented the proposed algorithm in MATLB R2008a using a PC with Intel® Core™ 2Duo CPU (E8400@ 3.00 GHz, 3.00 GHz) and 4 GByte RAM and 64 bit VISTA operating system.
To evaluate quality of the segmentation results, the dice correctness measure [43] is calculated using the following relation:
where Sa and Sr are the automatic and manual (reference) segmentation results, respectively, and N is the number of voxels in each bundle. Here, N(Sa ∩ Sy)is the number of the True-Positives. The Dice correctness measure is appropriately bounded, normalized, well-understood, and applied widely in evaluating segmentation methods. Two of the co-authors (a clinical expert and a technical expert) sat down together and carried out the manual segmentation which is considered as the reference segmentation results.
We tested sensitivity of corpus callosum Witelson segments to PDDx_Threshold for a normal subject. Figures 1 and 2 show the number of True-Positives, the number of False-Positives, and the Dice correctness measure over a range of PDDx_Threshold for the Witelson segments of the Corpus Callosum of a normal subject and a tumor patient, respectively. As shown in these figures, for PDDx_Threshold values within a specific range (here 0.5 to 0.6), the Dice correctness measure is maximized. For a higher PDDx_Threshold, both the number of True-Positives and False-Positives start to decrease, however, the number of False-Positives tend to saturate by increasing the PDDx_Threshold. This occurs conversely for PDDx_Threshold values lower than a specific range, i.e., both the number of True-Positives and False-Positives start to increase, however, the number of True-Positives tends to saturate by decreasing PDDx_Threshold. As seen, there is a small difference between the optimal selection of PDDx_Threshold for the normal subject and the tumor case, suggesting that we can apply the same PDDx_Threshold for all datasets.
Figure 1. Sensitivity of corpus callosum Witelson segments to PDDxThreshold for a normal subject. The graphs show number of True-Positives, number of False-Positives, and Dice correctness measure over a range of PDDxThreshold for Witelson segments of the Corpus Callosum.
Figure 2. Sensitivity of corpus callosum Witelson segments to PDDxThreshold for a tumor patient. The graphs show number of True-Positives, number of False-Positives, and Dice correctness measure over a range of PDDxThreshold for Witelson segments of the Corpus Callosum.
Figure 3 shows the number of True-Positives, the number of False-Positives, and the Dice correctness measure over a range of Collinearity _Threshold for the Witelson segments of the Corpus Callosum of a normal subject. It is shown that when Collinearity _Threshold values are in a specific range (here 0.65 to 0.75), the Dice correctness measure is maximized. However, the sensitivity of the segmentation method to Collinearity _Threshold is less than its sensitivity to PDDx_Threshold. We found the following set of parameters optimal for segmenting corpus callosum: PDDx_Threshold = 0.55, Collinearity _Threshold = 0.7, FA_Threshold = 0.1, and F_Threshold = 0.05.
Figure 3. Sensitivity of corpus callosum Witelson segments to Collinearity _Threshold for a normal subject. The graphs show number of True-Positives, number of False-Positives, and Dice correctness measure over a range of Collinearity _Threshold for the Witelson segments of the Corpus Callosum of a normal subject.
The tensor-based method proposed by Jonasson et al. [32] with NTPP similarity measure is quite sensitive to the speed threshold. If the speed threshold is selected high enough to prevent the front from propagating into the neighboring structures, corpus callosum is not segmented entirely (low sensitivity). However, if the speed threshold is chosen low enough to segment the entire corpus callosum, the front propagates into irrelevant fiber structures such as superior longitudinal fasciculus, cingulum, minor forceps, and tracts of corona-radiata (low specificity). Figure 4a shows the results of our implementation of their method. In this figure, we tuned the speed threshold so that the whole structure is segmented. Figure 4b demonstrates high sensitivity (segmenting almost the whole structure) and high specificity (without major penetration into the neighbouring structures) of our proposed method compared to the Jonasson's method.
Figure 4. Comparing of corpus callosum segmentations by the proposed method and the Jonasson's method [25]. In (a) for the Jonasson's method, the speed threshold was chosen low enough to capture the corpus callosum structure. However, the segmentation front propagates inside irrelevant fiber structures such as superior longitudinal fasciculus (cyan rounded rectangles), cingulum (green rounded rectangles), minor forceps (red rounded rectangles), and tracts of corona-radiata (yellow rounded rectangles). In (b), our method segments the corpus callosum structure with high sensitivity (segmenting the whole structure) and high specificity (without major leakage into the neighboring structures).
We have also compared the results of the proposed method with those of the Jonasson's method quantitatively. Table 1 shows the average Dice measures for different Witelson subdivisions of corpus callosum for the control subjects. Note that the best performance is obtained in the genu area with least penetration inside adjacent fiber bundles and the worst performance is obtained in the posterior mid-body subdivision with penetration mainly inside cingulum and tracts of corona-radiata. For the tumor patients, the performance of the Jonasson's method was poor and thus we do not present them.
Table 1. Comparison of the proposed method with the Jonasson's method
Table 2 shows the average Dice measure for different Witelson subdivisions of corpus callosum in the control subjects, Group 1 patients (tumor not infiltrating corpus callosum), and Group 2 patients (tumor infiltrating corpus callosum). Dice measures ranging from 90% to 98% indicate that the automatic segmentation results generated for the control subjects and the Group 1 patients are in excellent agreement with the manual segmentation results. For Group 2 patients where the tumors infiltrated corpus callosum, the Dice measures ranging from 81% to 92% indicate good agreements of the automatic and manual segmentation results.
Table 2. Average Dice measures for different Witelson subdivisions of the corpus callosum
Performance of the proposed method can be ascertained by visualizing the segmentation results (Figures 5, 6, 7). Figure 5 shows the segmentation results of the proposed method for 11 control subjects. Figure 6 shows the results for 12 Group 1 patients where the glioblastoma tumor does not infiltrate corpus callosum. These 12 patients were selected based on the severity of the effect of tumor on the rotation of corpus callosum. Note that although these cases include major geometric deviations from the normal state, the proposed method has successfully segmented corpus callosum and its subdivisions. Figure 7 shows the segmentation results for 7 Group 2 patients where the glioblastoma tumor has infiltrated corpus callosum. This figure illustrates that the proposed method has successfully segmented corpus callosum and its subdivisions in these extreme cases. Note that in all cases, the segmented corpus callosum does not penetrate into the adjacent fiber bundles such as cingulum, tapetum, minor and major forceps, superior longitudinal fasciculus, or tracts of corona radiata.
Figure 5. Segmented corpus callosum by the proposed method for 11 control subjects. The colors show the Witelson subdivisions results for the corpus callosum. Rostrum: blue, Genu: green, Rostral Body: cyan, Anterior Mid-body: red, Posterior Mid-body: turquoise, Isthmus: yellow, Splenium: gray.
Figure 6. Segmented corpus callosum by the proposed method for 12 glioblastoma patients with non-infiltrating tumors. The colors show the Witelson subdivisions results for the corpus callosum. Rostrum: blue, Genu: green, Rostral Body: cyan, Anterior Mid-body: red, Posterior Mid-body: turquoise, Isthmus: yellow, Splenium: gray.
Figure 7. Segmented corpus callosum by the proposed method for 7 glioblastoma patients with infiltrating tumors. The colors show the Witelson subdivisions results for the corpus callosum. Rostrum: blue, Genu: green, Rostral Body: cyan, Anterior Mid-body: red, Posterior Mid-body: turquoise, Isthmus: yellow, Splenium: gray.
Rotational effect of tumor on proposed method
We have used the geometric information of the diffusivity pattern in corpus callosum to prevent the front from penetrating into the neighboring structures. However, a tumor may change the shape and diffusivity pattern of corpus callosum from its original shape and diffusivity pattern.
To study the rotational effect of a tumor on the segmentation process, we rotate the segmented corpus callosum and its neighbors up to 5 voxels in different Euler angles (azimuth-elevation-skew), the tensor (T), and the principal diffusion direction (PDD) of each voxel for all control subjects.
where R(φ,θ,ψ) is the rotation matrix with respect to the spherical Euler angles of φ,θ and ψ respectively. R x (φ), Ry (θ), and Rz (ψ) are rotational matrices for rotations around x, y, and z axes, respectively. Then,
where (x, y, z) is the coordinates for a voxel within a 5-voxel neighborhood of corpus callosum, while (x', y'z') is the rotated voxel coordinates.
For each of the rotated coordinates, we calculate the tensor (T) and the principal diffusion direction (PDD) by:
The means and standard deviations of the Dice measures for the subdivisions of the corpus callosum rotated in different Euler angles (5, 10, 15, 20, 25, and 30 degrees) in 11 control subjects are shown in Table 3. The top, middle, and bottom rows represent the segmentation results of the rotated corpus callosum and its neighbors under different azimuth angles (around x axis), elevation angles (around y axis), and skew angles (around z axis), respectively. As can be seen from the Tables 2 and 3, the rotation of corpus callosum does not have a major effect on the segmentation results. It means that although the segmentation algorithm relies on the geometric information of corpus callosum and its diffusion pattern, it segments a corpus callosum deformed under the potential tumor pressure.
Table 3. Means and standard deviations of the Dice measures in 11 normal subjects where corpus callosum subdivisions are rotated under different Euler angles
We used the Wilcoxon two sample tests to compare sensitivity of the outer subdivisions (rostrum, genu, and splenium) and the inner subdivisions (rostral body, anterior and posterior mid-body, and isthmus) of corpus callosum with respect to the rotation. For two arrays A and B, the Wilcoxon test performs a paired two-sided signed rank test of the null hypothesis that data in the vector A-B come from a symmetric distribution with zero median. P-values less than 0.01 are considered statistically significant. From the p-values in Table 4, it can be inferred that the outer subdivisions have significantly lower average Dice measures than the inner subdivision for all azimuth and elevation rotation angles (p-values less than 0.0004). For skew angles, however, the outer subdivisions do not show significantly lower average Dice measures than the inner subdivision (5 out of 6 p-values are more than 0.01). Considering the overall diffusivity inside corpus callosum perpendicular to its main axis, the overall diffusivity pattern changes more dramatically around the x and y axes (azimuth and elevation) than around the z axis (skew). Therefore, the segmentation results are more sensitive to rotations in the azimuth and elevation directions. Figures 8, 9 and 10 show the segmentation results of the proposed method for the corpus callosum and its neighbors rotated 30° in the azimuth, elevation, and skew directions, respectively.
Table 4. The p-value of Wilcoxon two-sample tests between outer (rostrum, genu, and splenium) and inner (rostral body, anterior and posterior mid-body, and isthmus) subdivisions of corpus callosum
Figure 8. Segmentation results by the proposed method for a normal corpus callosum and its neighbors rotated 30° under the azimuth angle. (a), (b): Segmented corpus callosum in green overlaid on the T1 sagittal and axial images, respectively. (c), (d): Boundaries of the corpus callosum delineated in white in the sagittal and axial slices, respectively, overlaid on the color coding of the principal diffusion direction in each pixel.
Figure 9. Segmentation results by the proposed method for a normal corpus callosum and its neighbors rotated 30° under the elevation angle. (a), (b): Segmented corpus callosum in green overlaid on the T1 sagittal and axial images, respectively. (c), (d): Boundaries of the corpus callosum delineated in white in the sagittal and axial slices, respectively, overlaid on the color coding of the principal diffusion direction in each pixel.
Figure 10. Segmentation results by the proposed method for a normal corpus callosum and its neighbors rotated 30° under the skew angle. (a), (b): Segmented corpus callosum in green overlaid on the T1 sagittal and axial images, respectively. (c), (d): Boundaries of the corpus callosum delineated in white in the sagittal and axial slices, respectively, overlaid on the color coding of the principal diffusion direction in each pixel.
Novel aspects of proposed method
1. New similarity measure based on local diffusion characteristics
The proposed method is more accurate than the tensor-based method that uses the NTSP similarity measure [25]. Comparing with the manual segmentation by experts, we demonstrated accuracy of our proposed method even when the tumor infiltrates corpus callosum.
2. 3D segmentation of the entire corpus callosum
The proposed method works in 3D. Extraction of diffusion indices such as mean diffusivity and fractional anisotropy over the entire corpus callosum generates a reliable quantification of the structure that cannot be achieved by an analysis of the mid-sagittal plane only [4-7].
3. Preventing from penetrating inside neighboring fiber bundles
An optimal set of parameters is chosen to segment the entire corpus callosum (with high sensitivity) without penetrating into adjacent fiber structures (with high specificity). We have used Collinearity_Threshold to prevent the front from penetrating into cingulum. The threshold for the x-component of the principal diffusion direction (PDDx_Threshold) is used to prevent the front from propagating into major and minor forceps. FA_Threshold is also important to prevent from penetrating inside tapetum (as in general, it has diffusivity patterns similar to corpus callosum in crossing areas with lower FA values). To segment the entire corpus callosum in patients with low FA values, one should choose FA_Threshold and F_Threshold quite small. However, one should be cautious that in this case, the front may propagate outside of white matter in some areas.
4. Automatically extracting Witelson subdivisions of corpus callosum
The proposed method defines Witelson subdivisions of corpus callosum automatically.
5. Applicability to glioblastoma tumor patients as well as normal subjects using the same set of parameters
The proposed method has successfully segmented corpus callosum and its subdivisions in diffusions MRI data of normal subjects and brain tumor patients.
6. Evaluating potential effects of tumor on segmentation of corpus callosum
Depending on size, shape, type and proximity to the corpus callosum, the glioblastoma tumor may cause rotation, shrinkage or more severe disruptions like tearing of the corpus callosum fibers. Amongst the mentioned effects, we evaluated the linear rotational effect of tumor on corpus callosum. With this simplification and without loss of generality, we showed that the change in diffusivity pattern due to a tumor does not change the segmentation accuracy dramatically. However, if the effect of tumor infiltration inside the corpus callosum is sever and changes the structure dramatically, it may be impossible to segment the structure entirely and accurately.
Selection of initial seeds
The proposed segmentation method is seed-based and needs the initial seed points for hyper-surface to propagate. This requires the operators to define the seeds manually using anatomical landmarks. To automate the process, the initial seeds may be obtained from fiber atlases of control subjects [34,44]. However, when segmenting fiber bundles of pathological cases, abnormalities like tumors may change the fiber bundles and thus conventional atlas registration methods may not be applicable. To solve this problem, Zacharaki et al. [45] proposed a method for transferring structural and functional information from neuro-anatomical brain atlases into individual patient's data. Application of such methods in our case of segmenting corpus callosum in patients with tumors would be still in question.
Segmentation of fiber structures in HARDI
Since the tensor model is not capable of describing heterogeneous diffusion behavior in crossing fiber bundles, some studies segmented the desired fiber bundles using HARDI data. Generalizing the level-set method presented in [22] to the HARDI data, Descoteaux and Deriche [35] applied a region-based statistical surface evolution to the image of the ODFs to find coherent white matter fiber bundles. This is equivalent to the maximization of a posteriori probability which obtains the desired segmentation for the observed ODFs and presumes Gaussian distributions in different partitions of the Q-ball images. Although their method appropriately propagates through the regions of fiber crossings, it propagates the hyper-surface inside all of the crossing fiber bundles and segments them as a whole, not individually. They applied their method to extract corpus callosum and tracts of corona-radiata. However, their method is sensitive to initial seeds and suffers from limited anatomical knowledge of the operator who defines the seeds. In another study, a k-means algorithm has been employed to find the clusters using Euclidean distance as dissimilarity measure [36].
In a different study, a Position-Orientation Space (POS) is introduced by combining the geometric space with the spherical ODF space from the HARDI data, where two crossing fiber populations with different orientations in the spatial domain are resolved by applying a front propagation method in the level-set framework in a five-dimensional space [32]. Hagmann et al. [36] performed fiber bundle segmentation in POS based on the Markov Random Fields (MRF). In a similar study, McGraw et al. [37] proposed a mixture of von Mises-Fisher distributions to model the ODF again in MRF. Assuming that the spatial relationships are modeled by the MRF, this method estimates a hidden random field of fiber bundles from the observed ODF profiles using a Maximum a Posteriori (MAP) formulation. However, dimensional reinforcement of the problem causes disadvantages such as increasing the computational cost.
Using Spherical Harmonic Coefficients (SHC) as features of functions on the sphere [38], a method has been proposed for fiber bundle segmentation [33]. However, without masking the speed term with a measure of anisotropy (such as FA) that has low values in the crossing areas, the growing hyper-surface may penetrate into irrelevant fiber bundles that have common areas with the bundle of interest. In another work [34], the authors proposed an atlas-based method introducing a novel similarity based on PDD's and spherical harmonic coefficients. Integrating PDD's into the framework, along with a proper PDD-selection algorithm, leads to the segmentation of most of important fiber bundles in the brain without penetration into irrelevant fiber bundles that have common areas with the bundle of interest. Using an atlas [44] to find the initial seeds for the fiber bundles, the proposed method overcomes limitations of the semi-automatic methods that suffer from limited anatomical knowledge and subjectivity of the operator who defines the seed voxels. Note that since the number of diffusion measurements in the tensor data is not adequate for fitting SHC and estimating more than one PDD, we used the same methods originally applied on the HARDI data.
Although the success of recent studies in segmenting fiber bundles in the HARDI data is promising, such protocol in not being widely used in clinical centers. On the other hand, diffusion tensor imaging is clinically feasible and thus the tensor-based methods are of more interest.
In this paper, we have proposed a 3D method based on a new DTI similarity measure to segment corpus callosum and determine its subdivisions. The method propagates a hyper-surface within corpus callosum without penetration into the neighboring fiber bundles. Segmentation of corpus callosum, the largest commissural fiber bundle in the brain, makes it possible to quantify various diffusion characteristics in its subdivisions, opening new perspectives for monitoring disease evolution or prognosis.
Ethics statement
MRI and other data of the tumor patients originally acquired for patient care are retrospectively and anonymously used in this research to train, test, and evaluate the proposed methods. This usage was reviewed and approved by the Institutional Review Board (IRB) committee of Henry Ford Hospital, Detroit, Michigan, USA. Details of the data and results are described in the manuscript.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
MN implemented the algorithms presented in the manuscript, tested the algorithms, and prepared the first draft of the manuscript. RJ participated in the design and coordination of the study, helped with the testing and evaluation of the proposed method, and revised the manuscript. SS contributed to the manual segmentation, revision of the manuscript, and final evaluation of the results. AB performed the statistics on the segmentation results. HS contributed to the revision of the manuscript and analysis of the results. MR, QJ, TM contributed to the image acquisition, selection of the cases, and classifying them into different groups. All authors read and approved the final manuscript.
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Journal of Magnetic Resonance Imaging 2006, 24:549-555. PubMed Abstract | Publisher Full Text
Kubicki M, Styner M, Bouix S, et al.: Reduced interhemispheric connectivity in schizophrenia-tractography based segmentation of the corpus callosum.
Schizophrenia research 2008, 106:125-131. PubMed Abstract | Publisher Full Text | PubMed Central Full Text
Rosas HD, Lee SY, Bender AC, Zaleta AK, Vangel M, Yu P, Fischl B, Pappu V, Onorato C, Cha JH, Salat DH, Hersch SM: Altered white matter microstructure in the corpus callosum in Huntington's disease: Implications for cortical.
Neuroimage 2010, 49:2995-3004. PubMed Abstract | Publisher Full Text
Lundervold A, Duta N: Taxt T. Jain A: Model-guided segmentation of corpus callosum in MR images.
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Med Imag Analysis 2008, 12:191-202. Publisher Full Text
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Voineskos A, Rajji T, Lobaugh N, et al.: Age-related decline in white matter tract integrity and cognitive performance: A DTI tractography and structural equation modeling study.
Neurobiology of Aging 2010, in press.
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Eckstein I, Shattuck D, Stein J, et al.: Active fibers: Matching deformable tract templates to diffusion tensor images.
Zhukov L, Museth K, Breen D, Whitaker R, Barr A: Level set modeling and segmentation of DT-MRI brain data.
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Wang Z, Vemuri B: Tensor field segmentation using region based active contour model.
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Pre-publication history
The pre-publication history for this paper can be accessed here:


text:
Resolution: standard / high
Figure 4.
MnTBAP protects against MLP. The animal experiment, spinal cord injury, and tissue processing were described in the Methods section. After the epicenter was located, the sections 0.55 to 2.55 mm rostral to the epicenter were immuno-stained at 0.5-mm intervals with an anti-HNE antibody. Upper panel, photomicrographs of anti-HNE antibody immuno-stained sections. A, lower magnification of a HNE stained spinal cord section showing the morphology of cord section and indicating the cell counting area defined by horizontal and vertical lines drawn crossing the central canal in the center of the sections, as described in cell counting in the Methods section. B and C, higher magnification of HNE stained spinal cord sections at 1.55 mm rostral to the epicenter. B, saline-treated and C, MnTBAP-treated sections. The colored panels (D-F) show double-immuno-fluorescence staining with anti-HNE (D, green) and anti-NSE (E, red) antibodies, and immuno-colocalization of D and E (F, yellow). The color photomicrographs are at a higher magnification. Scale bars are 100 μm. Lower panel, spatial profile of MnTBAP protection against MLP. The HNE-positive neurons were counted, and the counts compared between MnTBAP-treated and the vehicle-treated animals at different distances from the epicenter. MnTBAP significantly (indicated by an asterisk*) reduced the number of HNE-positive neurons in the sections 1.55 to 2.55 mm from the epicenter. Error bars, mean ± S.E.M.
Liu et al. BMC Neuroscience 2013 14:23 doi:10.1186/1471-2202-14-23

subset: commoncrawl


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Power and Money
Wednesday, 20 Jun 2007 | 10:47 AM ET
LBO Lawsuits: The Effect On Deals Like Ceridian
Posted By:
Melissa Lee
Okay, let's say you're a shareholder in a company, and that company's just gotten a takeover bid from a private equity firm. That offer represented a 13.6% premium to the stock's closing price yesterday. You may think to yourself: I've got myself a nice little profit here. But wouldn't a 19.3% profit be that much nicer? No, I didn't pull those figures out from my fedora. That's the difference, according to Dealogic, between the average premiums in management-led buyouts versus non-management deals. And these days, shareholders are outraged by it, and bringing that rage to the courtroom.
»Read more
Tuesday, 19 Jun 2007 | 2:03 PM ET
Hot Hedge Fund Strategies: How To Get In!
Posted By:
Melissa Lee
130/30, 120/20, 140/40. No, they're not prescriptions from your eye doctor. They are the latest trend in the investing world, that allows traditional, long-term investors to use shorting to boost returns. Very simply, the funds leverage up to 130% (or 120% or 140%, depending on the flavor of the strategy) long exposure usually to an index or sometimes a basket of stock picks. They then short 30% (or 20 of 40%), betting against the stocks they think are overvalued. And voila! 100% net exposure.
»Read more
Friday, 15 Jun 2007 | 10:14 AM ET
Steve Schwarzman: Too Rich or Not For Congress?
Steve Schwarzman's wealth probably makes a lot of people jealous. He is, after all, fabulously rich. And that would be FABULOUSLY, in all caps. If Blackstone goes public, Schwarzman will become even more fabulously rich, to the tune of $677 million additional dollars, on top of retaining a 23% stake in the firm. And if that doesn't make you jealous, there's that Wall Street Journal profile of Schwarzman this week, (subscription required) which details, among other things, his upper class sensitivity to a butler's squeaky black shoes, and his and his wife's fancy for $400 worth of stone crabs on weekends.
»Read more
Thursday, 14 Jun 2007 | 8:27 AM ET
Hedge Fund Rankings: CNBC's on Your Side!
Posted By:
Melissa Lee
Every local TV news channel has some segment that helps some consumer in distress--someone wronged by a renegade dry cleaner who made a hole in a beloved cashmere sweater, or a pet owner who bought a mutt instead of a pedigree pure bred. Invariably, the segment is called something along the lines of "the Investigators," or "XYZ news channel On Your Side." This blog entry is my version of that regular feature on your local news.
»Read more
Wednesday, 13 Jun 2007 | 10:55 AM ET
Hedge Fund Con: What You Didn't See
Posted By:
Melissa Lee
Twelve minutes seems like an eternity in television land, but when you report an in-depth piece, there is inevitably juicy tidbits that end up never seeing the light of day. That's what happened with my look at the psychology behind a hedge fund con. It's the story of a college undergrad, Hakan Yalincak, who engaged in credit card fraud, hedge fund fraud and check kiting, in a classic Wall Street swindle. And here's the kicker: the targets of the scam were hedge fund traders and managers who worked at some of the most successful...
»Read more
Wednesday, 6 Jun 2007 | 12:14 PM ET
SAC & Jana Turn Up the Heat!
Posted By:
Melissa Lee
Imagine you're a CEO or board member of a publicly traded company and you get this letter, signed by two very powerful, very successful hedge funds: Dearest Sir, We believe you should make a huge acquisition because the company as it stands won't deliver the returns we want (I.E. not BIG enough!). By the way, we own a huge stake in your company, and we WILL make it bigger. (Read between the lines: Do what we say, or else.) XOXO, SAC and Jana.
»Read more
Wednesday, 30 May 2007 | 11:03 AM ET
Bigger is not Necessarily Better
Today, I focused on emerging private equity funds' outperformance versus larger, more established funds (see link to my CNBC TV report). But let's not forget about hedge funds. The same outperformance can also be found there.First a multiple-choice question: whom do you want running your hedge fund?A. A guy who's been running money for decades and has his wealth spread out across a big portfolio that may be worth more than yours may.B. A guy who's sunk almost all his net worth into the fund, so he's trading his own money, and stays up at night thinking about how he's got to make the fund work or he'll lose his house.
»Read more
Wednesday, 23 May 2007 | 10:11 AM ET
Hedge Fund Registration: No Silver Bullet
The effort to require hedge funds to register just doesn't die. After the court struck down the Securities and Exchange Commission's mandate to require registration, Sen. Charles Grassley picked up the torch. But Senator, consider the comments of the US Attorney for the State of Connecticut.
»Read more
Thursday, 17 May 2007 | 10:04 AM ET
Private Equity Targets and the $100B LBO
My, how things have changed... A matter of months ago, talk of the $100b leveraged buyout seemed rampant. In newspapers and on TV (and admittedly, on CNBC), there was prattle about private equity deals reaching gargantuan proportions. My friend and colleague Dylan Ratigan and I even had a bet going on how big the deals would get in 2007.And now, two big investment banks seem to be backing my side of the bet. Merrill Lynch, on a $100b buyout, saying: "the probability of such events occurring is less than generally thought." Morgan Stanley, meantime, saying a deal of that size would be "heroic." (Dylan, when can I collect my $5?)
»Read more
Friday, 18 May 2007 | 1:57 PM ET
Power & Money Special Report
Posted By: By CNBC.com
Private equity is reshaping the U.S. economy as well as its capital markets and is a force to be reckoned with.
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Book your room at Cocoon Hotel
Double RoomMax Occupancy: 2 guests (up to 1 child, 1 infant)
Double Room (with A/C)Max Occupancy: 2 guests (up to 1 child, 1 infant)
Triple RoomMax Occupancy: 3 guests (up to 2 children, 1 infant)
Triple Room with A/CMax Occupancy: 3 guests (up to 2 children, 2 infants)
Single RoomMax Occupancy: 1 guest
Single Room (with A/C)Max Occupancy: 1 guest
3.5-star family-friendly hotel, walk to Jade Museum
Collect 200 points
Simply enter your Nectar card number when prompted. Your points will be credited 30 days after you return from your trip.*Offers may apply
This family-friendly San Jose hotel is within a 10-minute walk of Children's Museum, Jade Museum, and Gold Museum. National Theater and National Center of Art and Culture are also within 15 minutes.
Hotel Features
This smoke-free hotel features a restaurant, a bar/lounge, and laundry facilities. Free cooked-to-order breakfast, free WiFi in public areas, and free self parking are also provided. Additionally, a 24-hour front desk, a computer station, and free newspapers are onsite.
Room Amenities
All 42 soundproofed rooms feature free WiFi and room service. Flat-screen TVs come with cable channels, and other amenities that guests will find include free local calls and ceiling fans.Information missing or incorrect? Tell us!
Hotel Amenities
Hotel Amenities
The hotel offers a restaurant. A bar/lounge is on site where guests can unwind with a drink. A complimentary breakfast is offered. A computer station is located on site and high-speed wireless Internet access is complimentary.
This family-friendly hotel also offers complimentary newspapers in the lobby, laundry facilities, and room service (during limited hours). Onsite self parking is complimentary. A total renovation of this property was completed in June 2012.
Cocoon Hotel is a smoke-free property.
- Computer station
- Babysitting or childcare (surcharge)
- Free WiFi
- Free newspapers in lobby
- Smoke-free property
- 24-hour front desk
- Airport transportation (surcharge)
- Number of floors - 4
- Bar/lounge
- Free breakfast
- Elevator/lift
- Laundry facilities
- Total number of rooms - 42
- Restaurant
- Free self parking
- Television in lobby
Family Friendly Amenities
- Family Hotel
- Free Wi-Fi
- Soundproofed rooms
- Laundry facilities
- Babysitting or childcare (surcharge)
Available in all rooms: Free WiFi
Available in some public areas: Free WiFi
Free self parking
Room Amenities
- Soundproofed rooms
- Flat-panel TV
- Free WiFi
- Blackout drapes/curtains
- Cable TV service
- Ceiling fan
- Free toiletries
- Desk
- Free local calls
- Daily housekeeping
- In-room safe
- Iron/ironing board (on request)
- Private bathroom
- Shower only
- Phone
- Room service (limited hours)
Where to Eat
Guests are offered a complimentary cooked-to-order breakfast.
Cocoon Hotel has a restaurant serving breakfast and lunch.
Room service (during limited hours) is available.
Hotel Policies
Check-in time starts at 2 PM
Check-out time is noon
Payment types
You need to know
Extra-person charges may apply and vary depending on hotel policy.
Government-issued photo identification and a credit card or cash deposit are required at check-in for incidental charges.
Special requests are subject to availability upon check-in and may incur additional charges. Special requests cannot be guaranteed.
- Airport shuttle fee: CRC 35.00 per vehicle (one way)


text:
Juvederm WORTH IT RATING DETAILS
in the last 24 months
in the last 12 months
over all time
Reviews from the Community
What was i thinking???????????????????? Doctor had no before or after pix and i fell for this at an "open house" where they provided sale discounts if you pre-paid......... Look at before and afters!!!!! I feel stupid and duped. Don't even think about doing this!!!!!!!!!!!!! Now... READ MORE
Juvederm in Smile Lines - Lancashire, England
I had this product injected into my lines as had lost weight and was looking very tired and old-where as botox improved my appearance this has left looking like a hamster !with the left side very lumpy! I wish I never had this procedure done and now feel I look older! I have contacted the place... READ MORE
**Update*****Was *NOT* Worth It and Not Nearly As Painful As I Thought It Would Be!
I went to a clinic in Vancouver BC and was very very nervous. I wanted them to look full and natural, but not like I had them done. After reading reviews of "juvederm gone wrong" I started to panic and started to leave but then went back in and said let just get this over with!! They took... READ MORE
Juvederm for Under Eye Bags - Calgary, AB
I am 35 and started noticing I always looked tired. I went to a place in Calgary Ab Canada, they filled up my undereyes and a little bit of my cheek bones with one syringe of Juvederm. I am very happy with my results. I had no bruising, the procedure was relatively painless as they gave me... READ MORE
I Look 80 Years Old from my Upper Lip Down and 48 from my Nose Up - Bakersfield, CA
It has been a month and a half now since my injections, I am getting worse day by day, looking older and older, it saddens me to think that someone I trusted wanted to put these toxins in my body which has deformed my face and now is though my entire system I am weak, tired and deprecated I... READ MORE
Not Happy with Juvederm - lopsided, wrinkles back after one week - Encino, CA
Here are my lopsided juvederm lips with all the wrinkles back after one week! Three syringes and 900.00 later!!! I went to a well known dermatologist. Now that the swelling is down nothing looks any different. I had my upper and lower lips injected as well as my chin and between the eyes... READ MORE
Wonderful Experience! - Wailea, HI
I work in Sales and I am 43, so I thought for Lucky 44 coming up I would refresh my look. I went in to see Dr. Harper who is wonderful, patient, kind and really listens to what you want. I decided on botox around my crows feet and my forehead line. I don't have the 11 so nothing was done here. I... READ MORE
It Removed my Eye Bags! Now I Just Need to Work on Lightening Up my Dark Circles :) - Taiwan, TW
Pro: got rid of my eye bags con: $$$, had a minor allergic rxn @ the injection sites Shared a syringe with mom (cost was for mom and me). READ MORE
Cheek Fillers and Lips - Laguna Niguel, CA
The new micro cannula that Dr. Klein is using offers little to no bruising! Overall I am extremely pleased with the results. My lips usually bruise, but with the new cannula there is absolutely no tell-tell signs anything has been done. I will be 49 on Saturday, and as we age we lose collagen... READ MORE
Great Results on Lips & "11s"
I had my first experience with dermal fillers a couple of years ago, when I went to a med spa for Botox to treat my glabeller "11s" because I was tired of being told I looked "angry" when I wasn't. While the spa was run by a licensed physician, I didn't find... READ MORE
Just Had Juvederm ...so Far So Good! - WI
I wanted a fuller upper lip and to change the turned down corners of my mouth. So the PS added some volume to my lower lip and then my top lip to make it balance out. He mentioned that marionette lines are the hardest to erase but he could soften them a bit. He used 1 vial. The process was quick... READ MORE
The Doctor Makes All the Difference with Fillers (Juvederm)
I was apprehensive about having my nasolabial and marionette lines filled bc I didn't want to appear puffy and was also concerned about the degree of pain. I've had botox done for years, but I've heard fillers are more painful. My doctor spent over an hour numbing me with a topical,... READ MORE
Bruises After Juvederm - San Francisco, CA
I have terrible bruises this time. I'll wait until the bruises and swellings are gone and then decide. Comparing techniques of the two doctors: my first one did about 2 injections on each side and used the regular Juvederm. No one, including me, noticed the difference, but I don't... READ MORE
Under Eye JUVEDERMA Treatment
Juvderma: My dermatologist injected Juverderma, it was for my deep sunken eyes and i have tear lines as well, but my skin is very thin. he injected in june it alomost 8months, but i got puffy eyes, he injected in excess, it looks horrible now, and even worse from earlier.,then he gave me to... READ MORE
Semi Pleased with Results - Stockton, CA
I love the idea of filling these dreaded signs of aging. I'm on a tight budget but appearance is very important to me. It was slightly difficult adjusting to the new look that I could see changed the shape and movement to my face. I feel the beginning is the strange phase. As it mellows,... READ MORE
Juvederm Eyes - Houston, TX
Ok I finally did it! I have terrible bags under my eyes and wanted to try restylane to fill out the "rut" She reccomended a full syringe under each eye but i was hesitant and she said lets try half. So we did and I wish I would have gotten a full one but I can go back ( I bought 2... READ MORE
Smooth Results but Doesn't Last As Long As Advertised, more bruising and swelling - Scottsdale, AZ
The juvederm ultra plus is slightly better than the regular juvederm. It always gives smooth results but you swell a lot for a week then it goes down a LOT. Disappointing if it's your lips that go away so fast. I work out a lot so I process fillers rather quickly. Perlane lasts longer for me... READ MORE
Help Juvaderm Injections Ruined my Eyes!
I had Juvaderm injected under my eyes to try to get rid of a sunken look. Not only did I get a black eye that lasted 5 months, now both my eyes are horribly puffy/baggy looking. WAY worse looking and adds years to my age.After hitting a bloodvessel in one of my eyes, the doctor left the room... READ MORE
NO! Hospitalized, Infection, Two Month on IV Antibiotics
Used it for my smile lines. Ended up hospitalized for 3 day with Cellulitis and a staph infection in my face. I had to have a pic line that goes into the main artery beside my heart so I can take IV antibiotics 4 times a day. It has been two months now. I get the pic line out today and will be... READ MORE
Self Injecting Juvederm or Hyaluronic Acid (Fillers) - Canada
Ok. We all know already this is not the best idea in the world so please, give up the hate mail and comments we as posters have heard it literally one million times. Thx. Did it for the cost effectiveness and that is x2 .8ml syringes rather than the Cosmo (Cosmetic Doc) which charges $500 for... READ MORE


text:
McMullan stays on with Cliftonville
Cliftonville's experienced midfielder George McMullan signs a new contract and will stay for a 15th season at Solitude.BBC Sport » 8d
Cliftonville's experienced midfielder George McMullan signs a new contract and will stay for a 15th season at Solitude.BBC Sport » 8d
Premiership champions Crusaders pick up the three top honours at the NI Writers' Association annual awards in Belfast.BBC Sport » 23d
Glentoran lift the Irish Cup but Portadown are angered by a controversial refereeing decision shortly before David Scullion's winner.BBC Sport » 24d
Portadown's Michael Gault says one of the assistant referees accepts the wrong call was made in the Irish Cup final controversy.BBC Sport » 24d
Glentoran beat Portadown to clinch a controversial victory over Portadown in the Irish Cup final at the Oval.BBC Sport » 26d
Portadown boss Ronnie McFall believes his team's firepower could be decisive in Saturday's Irish Cup final against Glentoran.BBC Sport » 27d
Sammy Morrow returns to Coleraine in a two-year deal just two days after the striker is released by Linfield.BBC Sport » 27d
Warrenpoint Town boss Barry Gray admits it will take "a major performance" from his side to claw back a two-goal deficit against Bangor.BBC Sport » 28d
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Automate your tediousyet essential business processes
Pyrus lets you automate the approval of proposals, orders, budgets, technical specifications, attendance lists, or any other documents essential to your business.
Tasks only appear in your inbox when you need to actually do something — when it's done, it disappears. We've made it simple to in a few seconds know exactly what your team expects from you and what you should be doing next — and when it's done, it's gone. Out of sight, out of mind.
Pyrus' Mobile Apps work even when you don't have internet access: the moment you get back online, it'll sync everything you've worked on offline.
Handle large volumes of requests, calls, orders or other tasks more efficiently by creating automated workflows — saving you clicks, time, and a little bit of your sanity.
Create flexible, custom access settings for each of your team members. Track your team's progress. Protect your data.


text:
Where to Spa Like a Celebrity
The Golden Door – Escondido, California
The Golden Door destination health spa sits on 377 acres in Escondido, just outside of San Diego. The spa was created by Deborah Szekely in 1958, and the Golden Door brand has since expanded to include similar retreats in Utah, Florida, Arizona and Puerto Rico. The original Golden Door pioneered the development of destination spas around the world, and continues to be the go-to getaway for wellness-minded travelers, including many high-profile celebrities. Surrounded by soothing nature and Asian-inspired gardens with koi ponds, guests visit The Golden Door for a weeklong journey in health, fitness, wellness and self-discovery. Based on your goals, a typical day may include a morning hike, afternoon water aerobics, guided meditation, anti-aging facial, mani/pedi, and organic meals custom created by Executive Chef Kayla Roche. The Golden Door offers the ultimate in privacy, with only 40 guests welcomed at one time, and is a favorite destination spa for such celebrities as Barbara Streisand, Martha Stewart, Nicole Kidman, and Lauren Graham.
Discover all San Diego celebrity spas on DiscoverSD.com


text:
We provide a range of courses activities and events with the aim of helping people of all ages to gain a deeper insight into themselves and the world around them.
There are three main strands to this work:
• Arts
• Mindfulness for Health and Well-Being
• Outdoor Learning
Most activities have threads of more than one strand running through them. Check out our What's On calendar for our full programme of activities
We also run a well established and popular Retreat Programme at The Barn Retreat Centre and at Sharpham House.


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School Girl StylesCategory: Education Games
Tags: school, girl, girls games, dress up game, school style
Dress up the school girl with the school clothes, and let her be ready to learn in the school, select the hair style and the sh...
Bubble BalanceCategory: Sports Games
Tags: bubble, balance, mouse, simple, classic, retro, old school
Test your mouse skills in this old school style balancing game. Simply keep your bubble alive for as long as you can, and kee...
ThumpCategory: Action Games
Tags: Thump
Great old school style van - course racing game. Race against time and try to win all 12 tracks.


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V.V. Subrahmanyam
HYDERABAD: Beating the heat! Well, it is not just the Hyderabadis, who are having a harrowing time during this scorching summer. The story is the same and more understandably so with the foreign 'recruits' in the Deccan Chargers team for the on-going DLF Indian Premier League.
The sight of a bare-bodied South African Herschelle Gibbs slugging it out with his team at Rajiv Gandhi Stadium (Uppal) was perhaps symbolic of this on Tuesday evening. No wonder, it is said that he spent the whole of five hours yesterday in the pool at the hotel, joined by his teammate Scott Styris, to keep himself cool as part of the preparations for scripting a change in the fortunes of his side in the IPL.
Well, the franchisee officials of Chargers might take immense pride from these pictures of the likes of Gibbs, Gilchrist, who drove straight to the ground from the airport on coming back from Bangalore this evening, as they seem to be still in the mood to charge their batteries even in the wake of dismal run.
"I had not experienced such a feeling in my cricketing career of more than three decades – a team losing so badly. You can imagine the situation," remarked a senior official of the franchisee. This was understandable considering that the hosts failed to drive in even the advantage of playing at home and losing all five game in-a-row.
Beaten they might be, but Chargers players seem to be not disgraced if the way the big guns have joined the grinding training session even today, under the supervision of chief coach Robin Singh, is any indication. The confident strides of the success stories – Rohit Sharma and Venugopala Rao – too remind that they still have plenty to give back to the team. Even the injured V.V.S. Laxman too joining them only to see and hope for a turn-around in the team's fortunes. Clearly, the mood is not despondent as every member is strictly following the training schedule prescribed by sports scientist Dr. Bhaktiar .


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The logical answers found for all the theoretical questions and doubts I raised for myself concerning those two important areas of modern physics are those I explain in this work to share them with my dear readers, being sure that its conceptual presentation will open up for them, as with me, new paths to arrive at an integral knowledge and understanding of physics; my main motivation and purpose being to have physics again placed under the aegis of logic, common sense and conceptual rigor in accordance with clear philosophical and epistemological basic rules, trying to avoid the ad-hoc building of geometrical and mathematical nirvanas in order to explain that which can be explained rationally and with simple words"
Enrique Morales-Riveira
October 2009
With solid scientific research, Rebuilding Modern Physics offers a new approach to physics, one which will clarify the dark, mysterious, intricate, and confusing areas of modern physics. Under the steady hand of Enrique Morales-Riveira, physics again becomes the realm of reason, logic, and reality.
In this epistemological discourse, Morales-Riveira shows how Minkowski's space-time, the theories of Special and General Relativity, the standard model for the physics of fundamental particles, and the current cosmological theories are based on irrational ideas and misleading experiments. This has caused modern physics to fatally become a kind of unrealistic science where common sense and physical reality do not have any place whatsoever. This is leading modern physics to an ominous dead-end street and preventing its climb to the next platform. His discussions include:
• Why it is imperative to urgently abandon the arbitrary and unnatural conception of Minkowski's space-time in modern physics.
• How natural space-time gives back to physics a lost symmetry, inner interdependence, unification, coherence, rationality, and simplicity.
• Reinterpretation of Newton's Theory of Universal Gravitation.
Though controversial, Rebuilding Modern Physics marks an inflexion point in the science of physics for future generations of physicists avid to unveil the truths behind time, space, energy, and matter.
Because the theories of Special and General Relativity and the standard model for the physics of subatomic particles seem extremely intricate, artificial, irrational, and contradictory and irreconcilable between themselves; I consider it a moral obligation and an act of loyalty with regard to physics and towards myself to submit this work for the consideration and analysis by physicists' and lay persons, as a seminal contribution to the advancement of physics in general, this work being an epistemological dissertation based on a pragmatic, discovery-helping process of reasoning and deduction, rather than a technical discussion with the mathematical detail and precision usually set forth in the presentation of modern physics.
The logical answers found for all the theoretical questions and doubts I raised for myself concerning those two important areas of modern physics are those I explain in this work to share them with my dear readers, being sure that its conceptual presentation will open up for them, as with me, new paths to arrive at an integral knowledge and understanding of physics; my main motivation and purpose being to have physics again placed under the aegis of logic, common sense and conceptual rigor in accordance with clearphilosophical and epistemological basic rules, trying to avoid the ad-hoc building of geometrical and mathematical nirvanas in order to explain that which can be explained rationally and with simple words.
In the first place I open the discussion explaining the reasons why the physics community must urgently abandon Minkowski's Space Time, because it is a framework of space and time that is leading modern physics down an ominous dead-end-street, where irrationality, and the indiscriminate use of ad-hoc mathematics and questionable quantitative experimental data, are creating a new physics where common sense and reality seem to have no place whatsoever, and where everything, absolutely everything, founds an explanation, no matter how absurd, unnatural and weird such explanation may be. On the other hand, I hope that a growing awareness and the certitude of the existence of a Natural-Space-Time, will give back to physics a lost symmetry, total unification, coherence, rationality and, above all, its innate simplicity. In the second place, I demonstrate that the Theory of Special Relativity is a theory that should be circumscribed exclusively to the electromagnetic-field phenomena, that is, to kinematics of quanta and of energy waves in the void, and to the dynamics of the exchanges of energy between electrically charged particles; it being incorrect to extrapolate that theory to the gravitational field.
In the third place, I thoroughly demonstrate that Newton's Theory of Universal Gravitation is the only correct and valid theory to explain universal gravitation, incorporating the barycenter for all the calculations of the gravitational forces between two bodies, simultaneously basing myself on time's dispensability as a phenomenon, or characteristic, of the propagation of Gravity between two bodies.
I use the theory of Special Relativity as a heuristic (discovery-helping) tool for the purpose of demonstrating what is stated above, and to discredit the alleged validity of General Relativity; unmasking the false paradigms and axioms on which said theory is based.
I also suggest various experiments in my work that will prove my theoretical basic principles, free of any ambiguous, vague numerical result and of second or third interpretations, contrasting noticeably with the experiments that have been conducted historically to demonstrate the validity of Einstein's Theory of General Relativity and to justify the standard model of the physics of subatomic particles, in furtherance of which the experimenters have attempted to anxiously fish for the truth in a turbulent river of infinitesimal data, fitting physical parameters that are too complex and abstract, which can vary quantitatively with the slightest of changes in the initial conditions of the adjustment of the measuring instruments.
I provide in the last chapter, as a result of my theoretical developments, a broad yet succinct explanation of a new theory of physics which integrates the gravitational field with the electromagnetic field, which allows one to explain rationally all the phenomena of physics, unifying the physics of subatomic particles with the physics of the large cosmic bodies scattered in space's length and breadth.
Nevertheless, this work is much more than that, since it should justly be deemed a new approach to physics, which I hope will contribute to clarifying very dark, mysterious, intricate and confusing areas of modern physics. Physics again becomes, then, the realm of reason, logic and reality, and not a virtual stage for irrationality and for mathematics to shine.
I presume at this point that the reader must be thinking that only an infinitesimally slim chance exists of one single person having discovered independently something completely new in physics. Well, maybe a stranger to the international scientific community is closer to finding himself in the privileged position of running into something revolutionary in physics than a specialist, since the latter is so deeply committed to his or her own area of specialization that he or she has neither the time nor the motivation or interest to question knowledge that he or she considers valid.
The author has conceived this work to reach a very wide audience of people with a genuine, enthusiastic interest in these topics, but not necessarily having formation and training in the science of physics. I have tried to make the demonstrations and explanations easily understandable for readers who only were to have a basic knowledge of mathematics and physics, attempting to arouse his or her interest for a more intense, in-depth exploration in the field of relativity, of universal gravitation and of the physics of subatomic particles.
The topics and discussions are organized and structured in a planned way with the idea of establishing a logical sequence in tune with the reader's cognitive abilities, using graphs and examples to make the whole thing easy and agreeable for him or her, always striving for the greatest simplicity, familiarity, easiness, rationality and meaning. The language used is devoid of any type of technical jargon, and all the explanations and demonstrations steer clear of labyrinthine, philosophical ponderings and complex, mathematical abstractions.
The international physics' community has reached a consensus in the sense that our visible universe is expanding at an accelerating rate, and will continue to do so until its thermal death.
Also, according to recent observations performed by many astrophysical teams, the international physics' community (astronomers, astrophysicists and cosmologists) has reached the conclusion that all visible three-dimensional space is flat. What is the consequence of this very important discovery? Well, the fact that the geometry of space is flat means that all points or coordinates of three-dimensional visible space are sharing the same present or now. That is, that a universal time exists for any universal observer, time then being a scalar physical parameter and not a vectorial one, as linear space actually is in any direction of three-dimensional space. On the contrary, if the geometry of visible three-dimensional space happens to be curved, or bent, time becomes a local or a positional (non universal) physical parameter, since different points or coordinates of three-dimensional space may have different times: ahead or advanced in time in reference to our local proper time.
Consequently, before getting into the formal definition of a Natural-Space-Time, it is advisable for the reader to understand the following:
° The absolute void has neither boundaries nor limits.
° The absolute void has no dimensions whatsoever. The three dimensions we are able to perceive materialize at the moment at which physical objects were to exist that would serve us as geometric references.
° The absolute void can contain everything but cannot be contained, because it is just a case of potential space; that is, space that remains to be materialized.
° Void space lacks movement and nothing moves in relation to void space. Consequently, all observers, whether inertial or not, are at complete rest in relation to the void, and vice-versa. That is why any observer, whether still, inertial, or in acceleration, cannot measure any speed or movement in relation to void space, because it lacks reference points that would allow him to measure absolute speeds. All distances and speeds are relative or geometrical, that is, they are measured relative to a reference point in space, or in relation to a coordinate system, where the observer himself, by definition, is the spatiotemporal origin of said reference system.
° The geometric space we manage to see with our eyes is isotropic (of equal physical properties along all axes), open and flat in its three spatial dimensions. Therefore, it can be represented mathematically by a three-dimensional vectorial continuum, that is, by a Cartesian coordinate system in which the three spatial dimensions are orthogonal among themselves.
° The absolute void, by itself, lacks reference points or geometric structure. Therefore, it cannot be a topological structure susceptible of being deformed, transported, or of curving, sectioning, contracting, elongating, bending, heating, cooling, twisting, rotating, etc., inasmuch as it lacks structure, mass, energy and electric charge. Geometric space materializes only when measurable distances separate bodies or objects.
° Time is a dimension we can sense but cannot see. We can sense time because all occurrences or events that take place in the Universe occur chronologically, that is, they are separated among themselves by a measurable amount of time.
° The time line, same as void space, has no borders nor limits or discontinuities; that is, it can shelter all occurrences or events that occur or may occur in the Universe, but it cannot be measured chronologically, since it, by itself, lacks events and doesn't possess a clock that can mark absolute time either. Chronological time, or measurable time, is the relative time that goes by between two events. All measurable time, as with all measurable geometric space, requires, then, an initial event and a final event to be able to be measured. Time can be defined as an always propagating, scalar - non vectorial - dimension that pervades all three-dimensional space, moving at a chronological, immutable speed of one unit of time per unit of time.
° Universal time propagates in quantum jumps of minimum possible, indivisible time units. Therefore, what separates the past from the future is not a line or a border, but rather a minimum time interval or fundamental granular time unit, something like the "width" of the present. If it were so, minimum possible space would be the amount of indivisible, linear space that would be swept by a pulse or quantum of light during that minimum possible chronological time, that is, the minimum possible amount of linear space or separation in the void between two fundamental particles.
° If light did not propagate like a wave, it would be impossible for us to perceive the three-dimensional space we permanently see.
° Light propagates in universal or absolute time throughout its entire path across void space. That is the reason why light permanently arrives to our position of observation just at our present or now, in all points of space, and from all points of same space; no matter if we are still, moving, or accelerating, and independently also of the motion of the respective light sources. Light is always a local or a proper physical phenomenon for any observer and for any detecting instrument, since light always propagates across the same present or now of the Universe. We see the light that arrives to our proper eyes, and not the light arriving to someone else's eyes.
° Space, time, mass and electric charge, apart from being granular or corpuscular, are identical or immutable for all observers in the Universe, regardless of the speed and acceleration they may have. Therefore, the size, form and age of the Universe are equal for all observers.
° We can assert that all observers and all cosmic bodies have always shared, now share and will tomorrow share the same present or proper time, and also same space. Therefore, everything that exists belongs to the same Universe, because everything was created at the present or now of the Big Bang or primeval explosion that gave life to the Universe in expansion we know. The Big bang, so to speak, synchronized, then, the present of everything that has existed, exists and will exist in the Universe. The Big Bang is the initial event starting from which chronological time, or measurable time, begins to run, as well as the point or place from which geometric or measurable space begins to extend. When events stop occurring, chronological time will reach its end. Likewise, the geometric space we know would come to an end if an infinite expansion of the Universe were to happen, in such a way that every particle would be at an infinite distance from the rest.
° The electromagnetic images we see of cosmic bodies in space, such as the planets, stars and galaxies, are images of their past, a past which is also our past. The farther away from us these bodies are, the more remote in time the images we perceive of them are. Therefore, the closer they find themselves to us, the more recent in time the images we receive of them are. How fresh or far away in time can the image we receive of a cosmic body be? Well, exactly the chronological time it takes the speed of light to travel the distance from the place the object was in the past up to our observation point in the present. Consequently, we never see the present or now of the objects, but rather an image of their past, even if they be located millimeters from our eyes. Nevertheless, we all share the same proper time, present, or now and the same geometric space, otherwise, the light emitted or radiated by said objects would never reach us.
° When we displace lineally through space, we not only travel a given distance, but also spend a certain amount of time in traveling said distance. The higher the speed, the less the time we need in order to travel said distance, and vice-versa. All the speeds we measure are a fraction or multiple of the speed of light C, which works as an absolute reference speed. The speed of light is the only absolute, non-relative or comparative measurement we can perform in any given reference system.
° When we move, neither does space contract nor time expand, that is, a second goes on being a second for us, just as a centimeter continues to be a centimeter, regardless of the speed at which we move. All measurements of time and space we perform are measurements of proper time and proper space; in other words, we never use a unit of contracted time or a unit of expanded time to carry out our measurements.
° Space and time cannot be active physical agents of any sort because they lack energy, mass and electric charge, the latter being the physical magnitudes that create the force fields that impart movement or impetus to ponderable particles by means of energy pulses.
° The Second Law of Thermodynamics establishes a defined and irreversible temporal direction for the sequence of all natural events occurring in the Universe, so that every event that takes place in the Universe is always preceded by another previous event that produces a subsequent effect-event or occurrence, and so on. Causes always precede effects, and not the contrary. Therefore, the Universe should go on expanding indefinitely, augmenting its entropy due to the irreversibility of all natural events. Therefore, it is irrational to believe in the possibility of a big crunch, or a return of the Universe to its original state, since it would require an external binding, or restitution energy, greater than the Big Bang's energy. In other words, it was impossible that the Universe could have reached its maximum entropy at the very moment of the Big Bang, since that would entail that all the potential energy of the Universe was converted, at that very moment, into kinetic energy.
Excerpted from Rebuilding Modern Physics by Enrique Morales-Riveira Copyright © 2009 by Enrique Morales-Riveira. Excerpted by permission.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.


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India's long wait for rate cut seen ending as RBI reviews policy
India's central bank is widely expected to make a modest cut in interest rates on Tuesday to support an economy set for its slowest growth in a decade, with a deeper cut unlikely due to worries over the fiscal and external deficits and inflation.
A Reuters poll earlier this month showed most economists foresaw the RBI cutting its policy repo rate by 25 basis points to 7.75 percent in the policy review, and follow it up with a cumulative 75 bps of cuts by the end of September.
Since the last cut nine months ago, the Reserve Bank of India (RBI) has resisted pleas from businesses and politicians for further reductions, putting the onus back on the government to take action.
But the central bank had held out hope of a cut sometime this quarter after Prime Minister Manmohan Singh's fractious coalition in September ended a debilitating phase of policy inaction to make urgently needed reforms to reduce the fiscal deficit and attract foreign investment.
The measures, which included giving foreign players more access to its retail and aviation sectors, helped India forestall the threat of a sovereign debt credit rating downgrade to junk status.
Recently, as part of an ongoing drive to trim spending, the government gave oil companies more room to set regulated diesel prices.
In December, inflation slowed to a three year low of 7.18 percent, further building expectations for a cut in rates.
Hopes of a large rate cut, however, were quashed after RBI Governor Duvvuri Subbarao said two weeks ago that inflation was still high.
His comment pushed the benchmark 10-year bond yield up to 7.89 percent from a 29-month low of 7.79 percent touched after the soft December inflation number.
In a report on the economy, issued a day before its policy review, the RBI spoke of taking a measured approach to support growth while balancing the risks.
... contd.


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Coco Chanel Baby Shower The talented Mili Ghosh designed and coordinated this Coco Chanel Baby Shower. Hints of blush pinks, white, and black made a classy and gorgeous color palette! Any mom-to-be would be oh so lucky to enjoy such an elegant baby shower brunch. The dramatic tall black centerpieces are adorned with pink roses. Pink candies + wafer cookies welcomed guests to the sweet … { read more }