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Although our knowledge remains incomplete, a great deal has been discovered about what happens in the brain during sleep: what areas of the brain become active or quiescent, how cellular activity changes, and which neurotransmitters (chemicals that carry signals between nerve cells) are released or blocked. Much has also been learned about the so-called biological clock, a small group of cells that keeps our sleep-wake cycle running on about a twenty-four-hour rhythm. This clock controls not only sleep but also variation in just about every other physiological system throughout the day. The cells that constitute it lie in a primitive area of the brain (the hypothalamus) that also controls many other important automatic functions such as hunger, thirst, temperature, and hormone levels.
Nevertheless, we do not fully understand why we need to sleep, what causes us to sleep, and what purposes sleep serves. There can be no single answer to these questions, in any case, because how you answer them depends on the level at which you approach sleep and waking. At the most basic level, that of neurophysiology, we can say we sleep (and wake) because of changes in the brain's chemical environment and in its cellular and electrical activity. On a higher level, that of function and behavior, we can say we sleep because sleep serves a restorative function for our bodies and perhaps our minds. Sleep certainly is necessary for us to function properly during the day: if we don't get enough of it we feel "sleepy," and this feeling can only be relieved by sleep. Finally, from an evolutionary perspective, the purpose of sleep lies in the benefits it provides for our survival. We can say, as various researchers have, that the purpose of sleep is to protect us from nocturnal predators, to rest the body, to maximize our alertness during the day, or to allow us to process memories. If we turn the whole question around and ask, "Why do we ever stop sleeping and wake up?" we could also answer in terms of physiology (because of chemical and electrical changes in the brain) or of function, behavior, and evolution (we need to be awake to eat, procreate, and care for our young).
Until the 1950s, doctors and other researchers believed that sleep was a single state distinguishable only from waking. However, we now know that sleep itself is divided into two distinctly different states: REM (pronounced as a single word, "rem"), or "rapid-eye-movement" sleep, and non-REM sleep. During non-REM sleep you lie quietly, with a regular heart rate and breathing pattern; it is probably closest to what we usually think of as "sleep," and it provides most of sleep's restorative properties. There is very little dreaming in this state, if any, although thoughtlike processes may continue. In REM sleep physiological systems are much more active, and it is in this state that we do nearly all of our dreaming. During the night you cycle back and forth between periods of non-REM and REM sleep as well as having the (usually brief) occasional waking.
Non-REM Sleep
After the earliest months of life, non-REM sleep divides further into four distinct stages. These stages range progressively from drowsiness to very deep sleep, and they can be identified in the laboratory by monitoring brain waves, eye movements, and muscle tone.
As you begin to fall asleep, you enter Stage I, the state of drowsiness. Although you are unaware of it, your eyes move about slowly under your closed eyelids. Your awareness of the external world begins to diminish as well. You have no doubt had the experience of becoming drowsy in a lecture or meeting. As you nod off, you miss some of the speaker's comments, yet you will jerk awake instantly if your name is called or if your head bends so far forward that you are about to fall off the chair. You might think you hadn't been asleep at all if it weren't for your lapse of awareness. On waking from this drowsy state, you might remember some thoughts of the kind usually described as "daydreams." Some people report seeing or hearing things more like the true dreams that occur during REM sleep, except that they are shorter, less well formed, and less bizarre.
If you allow yourself to continue the transition through drowsiness toward deeper sleep, you may notice a sudden jerk of your whole body that actually wakes you briefly and interrupts your descent into sleep. This "hypnagogic startle" is quite normal, although it does not happen every time we fall asleep.
Drowsiness really represents a transitional state between wakefulness and the more fully established stages of non-REM sleep, but we can only identify the arrival of the next stages for certain if we monitor the brain's electrical activity or "brain waves." At the onset of Stage II, short bursts of very rapid activity (called "sleep spindles") and large, slow waves ("K-complexes") begin to appear (see Figure 2. You can still be awakened easily from this stage, but you may not believe that you had really been asleep, depending on how long you had been in Stage II, how deep into this stage you were at the time of waking, and, as always, on variations between individuals. As in a waking from Stage I, you would probably not report any odd dream images, but you might describe some thoughts or daydreams.
As you fall into still deeper sleep, you enter Stage III and finally Stage IV (similar stages that together can be thought of as your deep sleep). The smaller and faster brain waves of waking and light sleep disappear, replaced predominantly by large, slow "delta" waves. Your breathing and heart rate become very regular, you may sweat profusely, and you will be very difficult to wake. Someone call easily rouse you, as they woulding your name will no longer easily rouse you, as they would from Stage II sleep; instead, you may be oblivious to the sound.
However, if a stimulus is important enough, you will likely wake even from Stage IV. Apparently, even in the deepest sleep our minds can still process some outside information. For example, although it may be difficult to wake you when it is your turn to get up and feed the baby, shouts of "Fire!" or a child's screams of pain will rouse you promptly. Yet even though you will wake in these emergencies, you will initially be confused. You may be aware that you need to take quick action, but you will have trouble "clearing the cobwebs" from your head so that you can think clearly and sort out what to do. The difficulty one has making the transition from Stage IV sleep to alert waking is very significant in several sleep disorders in children, as you will learn when we discuss sleep terrors, confusional arousals, and sleepwalking (Chapter 13).
In non-REM sleep your muscles are more relaxed than when you are awake. You are able to move (unlike in REM sleep, as we will see), but you lie still because your brain is not sending movement signals to most of your muscles. Disorders such as sleepwalking and sleep-associated head banging are exceptions to this rule.
REM Sleep
After one or two periods of non-REM sleep you cycle into REM sleep, a different state entirely. Breathing and heart rate become irregular. Your reflexes, kidney function, and patterns of hormone release change. Your body's temperature regulation systems are impaired, so you do not sweat or shiver. Males have penile erections in this state; females undergo clitoral engorgement and an increase in vaginal blood flow. The significance of these genital changes is not known.
REM sleep is an active state. Your body uses more oxygen than it does in non-REM sleep, a sign that you are expending more energy. More blood flows to your brain, your brain's temperature increases, and your brain waves become busy again, resembling a mixture of waking and drowsy patterns. The mind now "wakes up," but the wakefulness of the dream state is quite unlike that of true waking: you respond mainly to signals originating within your own body instead of those coming from the world about you, and you accept without question the bizarre nature of your dreams.
In this state your muscles have very poor tone, especially in the head and neck, and you become profoundly relaxed. Most nerve impulses that would otherwise pass down the spinal cord and out to the muscles are blocked within the spinal cord, so that not only are your muscles relaxed but much of your body is effectively paralyzed: signals to move may still be sent out from your brain, but they do not reach your muscles. Only the muscles controlling eye movements, respiration, and hearing are spared. Because this blockade is not complete, some of the stronger signals still get through to the muscles, causing frequent small twitches of the hands, legs, or face. So although REM sleep is very active in terms of metabolic and brain function, you remain fairly still.
(In babies, the blockade of motor impulses is not fully developed: more impulses get through to the muscles than in an older child or adult. As a result, a young infant in REM sleep will jerk, grimace, twitch, kick, and even make sounds. Of course, a newborn cannot get up, walk around, and get into trouble. The inhibitory system and the baby mature together, so that by six to twelve months of age—that is, by the time the baby can crawl or walk—most motor impulses are blocked and she stays safely in place.)
The most striking feature of REM sleep is its characteristic bursts of rapid eye movements. During these bursts, the heart rate, blood pressure, respiratory rate, and blood flow to the brain all increase and fluctuate irregularly. If you are awakened during one of these bursts, you will almost certainly report that you were having a dream, and the length of the dream you describe will correspond roughly to the time you had been in that state. Children as young as two have described dreams after such wakings. As for younger children, who lack sufficient language to describe dreams, we cannot know for certain that they do dream or what they dream about. However, since all the other features of REM sleep are in place at birth, it is reasonable to presume that even newborns dream. The first dreams are probably very simple repetitions of daily experiences (sounds, smells, sights); dreams then become more and more complex as higher brain centers and language develop.
We cannot say for sure whether your pattern of eye movements indicates that you were actually "watching" your dream occur. We suspect that this is partly true and that at least some of the muscle twitching corresponds to the actions taking place in the dream. Fortunately, because only a few of the signals to move actually reach your muscles, you merely twitch a little now and then, rather than getting up and moving about, dangerously acting out a dream. One thing this tells us is that sleepwalking and sleep terrors do not result from dreams or nightmares: such complex body movements simply cannot occur during REM sleep.
Some researchers believe that REM sleep has important psychological functions. Their research suggests that REM dreaming allows us to process daytime emotional experiences and transfer recent memories into longer-term storage. Such theories remain unproven. Certainly dreams have emotional significance, but their ultimate importance to the dreamer remains a mystery. REM sleep must serve some purpose, since we all dream every night—even those of us who think we don't—and if we are deprived of REM sleep for several nights in a row we compensate by getting more REM sleep than usual the next night. Yet, when people are deprived of most of their REM sleep for long periods of time, as a side effect of medication, for example, they don't seem to show any major ill effects. (Humans cannot be totally deprived of REM sleep, at least not easily. Such studies have been done in animals; complete elimination of REM sleep led to withering and even death.)
Waking a person from REM sleep can be easy or difficult, depending on how important the waking stimulus is to her and how involved she is in her dream. So the clock-radio may not wake you immediately from a really interesting dream; you may even incorporate something you hear on the radio into your dream. On the other hand, an important stimulus such as a burglar alarm will wake you easily and, unlike someone awakened from Stage IV sleep, you will become alert quickly.
To sum up, we seem to live in three distinct states. In the waking state we are rational and we can take care of ourselves and meet our survival needs. In non-REM sleep the body rests and restores itself while the mind rests. And in REM sleep the mind is again active, but it is not rational and it is "disconnected" from the body; major body movements do not take place even though the brain does send out signals to move.
One theory suggests that over the course of evolution REM sleep developed as an intermediate state between non-REM and waking, in which the mind would "wake up" before being "connected" to the body. An animal in non-REM sleep, lying quiet and still except for soft regular breathing, would be relatively safe from predators, but a sudden waking would leave the animal physically active yet confused and disoriented, and thus vulnerable to attack. An animal that first switched into REM sleep would become more alert, but with its brain still disconnected from its muscles it could not make any movement or sound that might alert a predator. Once it was sufficiently alert, the animal could wake fully; the muscle paralysis would disappear, and it could react appropriately to danger. This capacity to check for danger may still be important to humans. We all tend to wake up briefly after an episode of dreaming, and at that moment we are sensitive to anything amiss in our environment: the smell of smoke, footsteps downstairs, or quiet sobbing from the next room. If all seems well, we simply return to sleep, and in the morning we probably won't remember waking up at all. Young children often cannot return to sleep quickly after these normal arousals because something seems "wrong" to them—in one typical situation, it feels "wrong" that they are alone in their crib instead of in a parent's arms. This common problem is discussed in detail in Chapter 4.
How Sleep Stages Develop in Children
Sleep patterns begin to develop in babies even before birth. REM sleep appears in the fetus at about six or seven months' gestation, and non-REM sleep follows a month or so later. In the fetus and infant REM sleep is referred to as "Active Sleep" and non-REM as "Quiet Sleep." By the end of the eighth month of gestation, both states are well established.
In the newborn, Active Sleep is easy to identify because the baby twitches and breathes irregularly and you can see her eyes dart about under her thin eyelids. Sometimes you may also see her smile briefly. In Quiet Sleep she breathes deeply and lies very still; occasionally you may see fast sucking motions, and now and then a sudden body jerk or "startle."
Quiet Sleep is still somewhat different from the non-REM sleep of older children and adults. For one thing, it is undifferentiated: the division into separate, distinguishable stages comes later. The brain waves in Quiet Sleep show large slow waves occurring in bursts rather than in a continuous flow. During the first month of life the non-REM brain waves become continuous and startles disappear. By the time a baby is a month old, sleep spindles begin to appear, and over the next month or two we can begin to separate non-REM sleep into lighter and deeper stages. K-complex waves (see Figure 2), characteristic of mature non-REM sleep, do not appear until a baby is about six months old, although precursors appear earlier.
REM sleep is the earliest stage to form. Premature babies spend 80 percent of their sleep time in this state; in full-term infants it makes up half of their sleep. We do not fully understand why REM sleep is so prominent in the early stages of development. We do know that Quiet Sleep requires a certain degree of brain maturation, so one would expect to see less of that stage in newborns. In REM sleep, the higher centers of the brain receive stimulation from deeper, more primitive areas. Impulses come up the same sensory pathways that are used for sight and sound, and perhaps touch, smell, and taste. Later on, such stimuli are probably incorporated by the brain into dream imagery. While we can know nothing of infants' "dreams," this state might allow the baby's developing brain to receive sensory input—to "see" and to "hear"—even before birth. This input might be important to the development of the higher brain centers.
We also know that the baby in the uterus makes no breathing motions in non-REM sleep. If respiratory movements were never practiced, the child would be born with no experience at all in using these muscles that are so vital to survival. However, respiratory motions do occur in REM sleep, and it may be that the baby is also practicing other kinds of motor activity. Muscular impulses in a fetus are not blocked as completely as they are in children and adults, so the fetus has some ability to practice actual body movements in REM sleep. Fortunately for the mother, there is still some blockage of motor impulses during REM sleep, or the baby might never be still!
It may be, then, that REM sleep is most important in the early months as the fetus and baby develops, and progressively less so with increasing age. In fact, although at birth a full-term baby spends half of her sleep time in the REM state, only one-third of her sleep will be REM by age three, and she will reach the adult level of 25 percent by later childhood or adolescence.
Children's Sleep Cycles
During a period of sleep, children (and adults) cycle back and forth between REM and non-REM sleep. Once non-REM sleep has developed four distinct stages and most of the baby's sleep time has consolidated into a single nighttime sleep period, the sequence of sleep stages settles into a cyclical pattern that remains fairly constant throughout life. It is important to know something about these sleep cycles if you are to understand the development of normal sleep patterns in your child and the nature of any sleep problems that may occur.
As a child grows from a newborn to an adolescent, the length of the sleep cycle increases from fifty to ninety minutes; also, the total amount of REM sleep and the percentage of sleep time spent in REM decrease until they too reach adult values. The total amount of Stage IV non-REM sleep also decreases throughout childhood and adolescence as total sleep decreases, but it continues to account for about a quarter of the child's total sleep.
A newborn enters REM sleep immediately after falling asleep. By about three months of age she will enter non-REM first, a pattern that will continue for the rest of her life. Unlike adults, who achieve deep sleep only gradually at the start of the night, young children usually plunge through drowsiness and the lighter stages of non-REM sleep into Stage IV within a few minutes (see Figure 3). In youngsters Stage IV is an extremely deep sleep, and waking a child from that stage may be almost impossible. For example, if your child falls into Stage IV sleep at night in the car, you can probably carry her into the house, change her into her pajamas, and put her in bed with only the slightest sign of movement or arousal. Even a child who always seems to wake when put into her crib after being rocked to sleep will remain asleep as long as she is not placed into the crib until she has reached Stage IV. And if you wake your child from Stage IV sleep to go to the bathroom, she may do so in a semi-awake state and then return to sleep instantly without any recollection of the arousal in the morning. This partial arousal is very similar to what happens during sleepwalking and sleep terrors (see Chapter 13).
A child remains in Stage IV for about an hour or two. After that she undergoes a brief arousal. This partial waking may last for only a few seconds or up to several minutes. Her brain waves change abruptly, showing a mixture of patterns from deep sleep, light sleep, drowsiness, and waking. She will probably move about, perhaps rubbing her face, chewing, turning over, crying a little, or speaking unintelligibly. She may even open her eyes for a moment with a blank stare or sit up briefly before returning to sleep. Occasionally, and briefly, she may even wake fully before the progression of sleep stages continues.
There is actually a spectrum of behaviors that can occur during these arousals. The mild ones just described are quite normal. More dramatic behaviors may also occur at these times, including sleepwalking, sleep terrors, and confused thrashing. These events all occur during partial waking from deep non-REM sleep, and in all of them the child shows features of both sleeping and waking at the same time. We will discuss these behaviors at length in later chapters, but for now remember that they are not stimulated by a dream. As noted above, true dreams, including nightmares, occur only during the REM state.
After the brief arousal, there follows a period of a few minutes resembling drowsiness or, perhaps, the beginnings of REM sleep. There may actually be a short REM episode at this point, especially in adolescents and adults, but young children tend to skip it. The first REM episode, whenever it appears, tends to be relatively short—five to ten minutes—and not very intense. There are not many eye movements, and the child's breathing and heart rates remain fairly stable.
Following this episode of REM or "almost-REM," the child enters another cycle of deep non-REM sleep. In young children, the descent back into Stage IV sleep will probably be quite rapid, although not as rapid as it was in the first cycle. This period of deep sleep lasts between thirty minutes and two hours (depending, somewhat, on the child's age), and the arousal that follows it marks the end of the deep sleep period that characterizes the first third of the night. Thus, in children, the first three or four hours of the night are spent mainly in very deep sleep from which the child is not easily roused. Parents are often aware of this fact, because the period of lighter sleep that follows, with more frequent wakings, may well begin at about the time they are going to sleep themselves.
The arousal that ends the initial three or four hours of deep sleep will almost certainly be followed by a REM episode lasting five to twenty minutes. This period of REM sleep may be interrupted by several brief wakings, each followed by a rapid return to sleep. (In babies, REM sleep is particularly unstable, interrupted fairly frequently by brief movements and wakings; however, by the time the baby is around six months old, the inhibition of motor activity is more complete and REM sleep becomes more continuous.)
The REM episode ends with another brief arousal, and the child moves about, adjusts her position, subconsciously checks to see that everything is normal, then goes back to sleep. This momentary awakening has several functions. Changing position is important for the health of skin, muscles, and joints, and the child can check to see that things are the same as when she went to sleep. It is important to be aware that these wakings occur in all children and adults and are quite normal. Parents often perceive them as abnormal, especially if the child cannot return to sleep afterward because the conditions she associates with falling asleep—such as being rocked or patted—are no longer present. This problem of sleep associations will be discussed more fully in Chapter 4.
The middle part of the night, after the first REM episode, begins with another period of non-REM sleep followed by another arousal and a longer and more intense REM episode. Throughout this part of the night, usually lasting about four hours, the child alternates between progressively longer and more intense periods of REM and relatively light periods of non-REM sleep. It is during these hours of light sleep, particularly at the transitions between REM and non-REM sleep, that wakings are most common. Normally these wakings are brief, but it is also at these times that problems of sleeplessness tend to be most severe. Even adolescents and adults may notice that they seem to wake more easily in the middle of the night (to use the bathroom, perhaps) than they do in the morning when their alarm goes off for the day (see Chapter 9). Some children who are kept in bed too long at night sleep only at the beginning and the end, and this middle period of light sleep becomes one of full waking (see Chapter 11).
As morning approaches, children descend once more into fairly deep Stage IV sleep before the final waking; thus the last one or two hours of the night are often quiet, regardless of what came before. Children who tend to wake for the day directly out of this Stage IV period may seem to wake unhappy or crying every morning. The crankiness usually lasts only about ten minutes, and although it may seem worrisome, it is not a cause for concern. Other children, who reenter lighter Stage II or REM sleep before waking, are more likely to wake in good spirits. There is nothing you can do to change the sleep state out of which a child wakes spontaneously.
The very deep sleep that children experience at the end of the night is uncommon at older ages. This isn't because the capacity for such sleep is lost, but because adults rarely sleep long enough to allow it to emerge. An adult who sleeps eleven hours or so, or an adolescent who sleeps late on the weekend, may show the same end-of-the-night deep sleep typical of young children. A need for deep sleep built up during the day presumably explains why there is deep sleep at the start of the night, but it does not explain why there is more deep sleep at the end. The return to deep sleep near morning is an inherent feature of our sleep cycling system, one controlled by our biological clock (see Chapter 9).
This overview should give you an idea of what is actually happening to your child during the different stages of sleep during the night. It will also help you decide what state your child is in, based on when she fell asleep and what her sleep behavior is like at a given time. These observations will be important as you try to understand what sort of sleep problem your child has and how to deal with it.
Sleep and Waking Patterns
As you read through this section, keep in mind that the sleep requirements described are only approximate and are not the same for all children.
A newborn baby sleeps about sixteen hours a day, but for no more than a few hours at a time. She goes through about seven sleeping and waking periods distributed fairly evenly throughout the day and night. These episodes, which vary from twenty minutes to five or six hours in length, begin with a period of REM sleep, and, depending on the length of the sleep time, they show several REM/non-REM cycles. Even when your baby sleeps well for a few hours, you can usually observe brief arousals. In the early weeks there may seem to be no pattern to the sleep cycle—shorter and longer periods of sleep and waking are scattered over each twenty-four-hour period and vary from day to day.
When the baby is around three months old, daytime sleep settles into a three-nap pattern, with the main naps in the midmorning and midafternoon and, generally, a brief nap in the early evening. (Naps are further discussed below and in Chapter 12.) By the age of three or four months, your baby still sleeps about thirteen hours a day, but now her sleep pattern has consolidated into about four or five regular and predictable sleep periods, with two-thirds of her sleep occurring at night. By now there should be a clear and appropriate differentiation between day and night. At this age most infants have "settled," which means they are now sleeping through most of the night, at least from a feeding late at night to one in the early morning.
By six months almost all infants have settled, and the periods of continuous nighttime sleep have grown longer. The pattern of settling varies with each child, of course, and your baby's nighttime wakings may diminish very gradually, or she may settle quickly, as if suddenly forgetting the remaining nighttime feedings. Some babies settle very erratically. In any case, at some point between three and six months, your baby should be sleeping well at night. A typical six-month-old baby sleeps about twelve or thirteen hours total. Nighttime sleep typically lasts about nine and a quarter hours (and as long as eleven hours if daytime naps are short) with only occasional brief wakings. In addition, she will take two one- to two-hour naps each day, one in midmorning and a second in the afternoon. (The evening nap is usually dropped at around this age.) On most schedules, the morning nap will start between 9:30 and 10:30 A.M., and the afternoon nap between 2:00 and 3:00 P.M.
At one year, most children are still sleeping close to twelve hours, with nine or ten of these hours occurring at night. Most youngsters give up their morning nap at this point or within a few months. The single nap that remains generally follows lunch and occurs at 12:30 or 1:00 P.M., between the times where the two naps had previously been. At the transition to a single-nap schedule you may see other, related changes. Since the child now stays awake for longer stretches, sleep may come more easily both at nap time and at night. (This is often particularly noticeable if there were problems before.) Also, although the second nap may have been dropped, total sleep time generally does not change: either the remaining nap or the nighttime sleep lengthens.
By age two, your child should still sleep about nine to ten hours at night, with a one- to two-hour nap after lunch—about eleven and a half hours total. She will probably continue her afternoon nap until at least age three; some children stop by age two, and others continue napping up to age five. The dropping of the final nap is the least predictable of all the developmental changes in napping in the first five years. However, most children stop napping somewhere between their third and fourth birthdays. Those who tend to sleep longer at night, perhaps eleven hours, may simply not be able to sleep during the day. A child who develops this sleep pattern too early may not make it through the day functioning well. Cutting back that child's nighttime sleep to nine or ten hours may allow the nap to reemerge (see Chapter 12). Some children continue napping when the circumstances are especially conducive to sleep (for example, in the car) or at day care or preschool (where there is strong pressure to lie quietly during a prescribed rest period) but refuse to nap at home or on the weekends.
From age three to adolescence, children need gradually less and less sleep, but the decrease is smaller and far more gradual than was previously thought. Once children are past the toddler age they rarely nap, and they slowly begin to sleep less at night, dropping from about eleven hours in the preschool years to about ten hours in preadolescence. The years from five to twelve years of age are really the most wakeful in a child's life. Children between those ages generally sleep well at night and "wake well" during the day. The ability to nap in the afternoon is mostly lost (even in siesta cultures); occasional naps may suggest illness. A child who naps most days, especially in school, may have a sleep disorder such as narcolepsy (but, as discussed in Chapter 18, even narcoleptic children at this age may only nap occasionally). Chronic sleep loss at night can cause napping, but that pattern is unusual in the school-age child; instead, the more common consequence of insufficient sleep is behavioral change during the day.
During the four years of puberty rapid changes occur in the child's body, but the total sleep requirement stays about the same. Children aged fourteen to seventeen still need at least nine hours of sleep for optimal functioning, but few actually get that much, at least on school nights.
Remember, sleep requirements vary among children and families. However, if your child is getting one to two hours more or less sleep than the amount shown for her age in Figure 1, you should at least suspect that her sleep may need adjustment. I hope that the remaining chapters will help you to decide whether she has a problem and, if she does, to identify the cause and correct it.
The Importance of Biological Rhythms
To understand certain childhood sleep problems, we need to look beyond the sleep patterns themselves to the biological systems that control them. The term circadian rhythms refers to biological cycles that repeat about every twenty-four hours. All of us have many such rhythms. They include patterns of sleeping and waking, activity and rest, and hunger and eating, as well as fluctuations in body temperature and hormone release. These cycles must be in harmony if we are to have a sense of well-being during the day. Our ability to fall asleep and stay asleep is closely tied to the timing of these cycles. Typically we fall asleep as our body temperature is dropping toward a daily minimum, and we wake up as it starts rising toward a peak. If we have to wake up at a time when our temperature level is low, we do so only with great difficulty. Similarly, we have trouble falling asleep when our body temperature is still high and has not yet begun to fall.
It is important to know that, in all of us, these cycles are inherently somewhat longer than twenty-four hours. The difference is a matter of only a few minutes. However, exposure to artificial light in the evening, after sunset, and to artificial darkness in our bedrooms in the morning, after sunrise, makes the internal clock run still slower, functioning as if its inherent cycle length were closer to twenty-five hours. We reset the clock's timing each day through exposure to light in the morning and darkness at night. However, on weekends or vacations, when our schedules are more flexible, many of us begin to operate on this twenty-five-hour day: we go to bed later and get up later. Then we have great difficulty readjusting to the earlier schedule when we return to work or school. This problem, called a sleep phase delay, is discussed in Chapter 10.
Although it is not difficult for us to stay on a twenty-four-hour cycle if we keep to it regularly, problems arise when our routines are irregular or when we try to sleep at times that conflict with our sleep-wake rhythms. Shift workers and adolescents, both of whom tend to sleep different hours on weekdays and weekends, as well as people who travel across time zones, all suffer the malaise, sleep difficulties, and lack of well-being commonly referred to as "jet lag."
So do children whose sleep cycles have been disrupted or shifted or whose sleep schedules are variable, inconsistent, or otherwise inappropriate. These children may sleep poorly at night, and they may be sleepy or behave badly during the day. It is important to understand this effect, because treatments for problems related to sleep schedule abnormalities are very different from those for other sleep disorders. Besides, even when sleep schedule abnormalities are not the primary problem, their existence often complicates other sleep problems and must be taken into consideration when planning treatment.
The biological rhythms controlling sleep, the ways they can be affected by inappropriate sleep schedules, the various sleep problems that can result, and the ways these sleep problems can be treated are discussed in greater detail in Chapters 9 through 12. For now, remember that normal circadian rhythm function is necessary for normal sleep and optimal daytime function, and that many abnormalities having to do with circadian rhythms are quite simple to identify and correct.


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Recent release of two men's basketball players brings hot-button NCAA topic into local spotlight
On the small scale, the decision not to renew the scholarships of Luke Hager and Nate Anderson allowed Kevin Keatts to hasten the process of remaking the UNCW men's basketball roster to fit his system.
In the wider picture, the first-year coach's plan to renovate the Seahawks called to the forefront a central tenant in the national conversation on NCAA reform.
UNCW is, by NCAA rule, allowed to offer multi-year scholarships but chooses to put all its athletes on year-to-year renewal.
Athletic director Jimmy Bass said it's the first time in his four years a men's basketball scholarship hasn't been renewed, but he backed Keatts on the choice, provided Hager and Anderson had the opportunity to stay at the school.
Anderson will have to pay some tuition out of pocket to remain at UNCW and graduate next May, while Hager has transferred to Division II Hawaii Pacific, where he plans to play his final two seasons on scholarship.
"I think after (Keatts) had been here he had an opportunity to review the program and … look and try to plot how scholarships were going to be used over the next few years," Bass said. "That wasn't something we discussed during his job interview or the first week he came back here. He was here on the ground and had some time to look at the program and get to know the kids and then he came with the recommendation."
How things got here
In October of 2011, the NCAA Division I board of directors made a rule giving individual schools the opportunity to provide multi-year scholarships. The decision was nearly vetoed just a few months later.
More than 60 percent of the 330 voting members – including UNCW – wanted to keep the one-year limit in place, but they fell two votes short of the required number of a five-eighths majority to reverse it.
The issue has become an increasing point of debate. On July 9, NCAA President Mark Emmert testified before a Senate committee that athletes should receive "scholarships for life."
Major conference schools, such as Southern California and Indiana, have recently pledged to make all scholarships guaranteed for four seasons of athletic eligibility.
UNCW's student-athlete handbook specifies the department does not issue multi-year scholarships and lays out the process for annual renewal, which mirrors NCAA guidelines. Athletes are notified in writing by July 1 whether a scholarship has been renewed for the following academic year.
If athletic financial aid is reduced or removed, athletes are offered the chance for a hearing before an appeals committee made up of three university representatives from outside the athletic department. Neither Anderson nor Hager opted to appeal.
Bass declined to reveal instances where financial aid has been reduced or not renewed with other UNCW teams, citing student privacy regulations.
It does happen, though. Women's basketball coach Adell Harris chose to not bring back three players who had eligibility for last season, leaving her team with one of the youngest and thinnest lineups in the country.
Commissioner Tom Yeager said none of the schools in the Colonial Athletic Association offer across-the-board multi-year guarantees, though there may be special cases. His office doesn't track individual instances where its members don't renew scholarships, but he thinks the current system is largely self-policing.
Athletes are often successful in the appeals process, and coaches know a history of broken promises will hurt on the recruiting trail.
"I think that schools will make their own decisions," Yeager said. "They're going to treat their student-athletes fairly. You're always going to have checks and balances to a certain extent."
UNCW enters new landscape
Keatts has declined to talk specifically about the decision to not bring back Hager and Anderson. The coach has simply characterized it as the right move for the program.
Hager took the high road when the news broke last month, but noted UNCW didn't return his loyalty.
He passed up the chance to transfer when the Seahawks were banned from the postseason for the 2012-13 season.
Bass said the recent rise in transfers nationally has created a new culture for players and coaches to navigate.
"How well I know that," Bass said. "We had a ton of transfers in the women's program that crippled it, too. That's the system in the NCAA. Luke has gone and made a good decision. He's got two more years of eligibility. He's going to a great school in a great location."
With the open scholarships, Keatts was able to add UNC-Charlotte transfers Marcus Bryan and Denzel Ingram to the roster. Both players – and fellow transfers Jarvis Haywood and Chris Flemmings – will sit out 2014-2015 per NCAA transfer rules.
"I think we filled some needs," Keatts said.
Anderson – who missed all of last season with a knee injury – didn't return to the team for summer workouts, and Hager was told he wouldn't be back midway through the first session of summer school.
Changes were inevitable as Keatts took over a team that has lost at least 20 games in five of the past six seasons.
Senior forward Cedrick Williams said he knew the new staff was evaluating the holdovers this spring and wasn't surprised the former Louisville assistant wanted to "bring in some of his guys."
Keatts didn't directly address his decision to move on without Hager and Anderson with the current players, according to Williams.
"He didn't have to," Williams said. "We all knew: It's part of the business."

subset: commoncrawl


text:
Soy Sauce Naturally Brewed In Wooden Bucket. Passing Down The Disappearing But The Genuine Taste
Although it costs much, we have to pass down the genuine taste of naturally brewed by wooden bucket; their words are impressive. The warehouse is designated as a tangible cultural property. And their soy sauce brewed in wooden buckets, made over 100 years ago, is the real genuine taste that the technological advances can't imitate.
PlaceYamaroku Shoyu


text:
VideoHive Cube Cutout Logo 868825
After Effects Project Files \ Logo Stings \ Retro
Cube Cutout Logo 868825 by Sharky @ VideoHive
After Effects Project Files \ Logo Stings \ Retro
After Effects Version: CS3, CS4, CS5 File Size: 90.6Mb Requires Plugins: No Resolution: 1920x1080
Key Words: 3d, boolean, clean, cube, cut out, digital, fun, grunge, loft, neon, retro.
This template is compatible with After Effects CS3 and above. Please ensure you have updated your After Effects and have all default plug ins installed. Audio file is only a preview with a watermark. For the full music track, grab http://audiojungle.net/item/glitchy-digital-crystal-logo-02/57406 http://audiojungle.net/item/glitchy-digital-crystal-logo-02/57406
- Fast and easy to edit.
- Customize your colours and objects.
- Easy to understand video help files available online.
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Cut the cube!
Hope it is useful and helpful for you! Thank you for your time! Enjoy!
Download Link


text: Battle and Get! Pokemon Typing DS Yes, it finnaly arrived from PlayAsia after months of being sold out in Japan Damned happy to have this in my Collection now The DS stand is perfect for all types of DS/DSi even the 3DS. It's a nice addition that you can place your Gamecard in the stand and fold it, so you don't have to carry the gamecardbox with you.


text:
Japanese space scientists are set to trial a tether they hope will help pull junk out of orbit around Earth, clearing up tonnes of planetary clutter, they said Thursday.
Researchers at The Japan Aerospace Exploration Agency (JAXA) have developed what they called an electrodynamic tether made from thin wires of stainless steel and aluminum.
ANALYSIS: Casting a Net for Space Debris
The idea is that one end of the strip will be attached to one of the thousands of dead satellites or bits of rocket that are jamming up space and endangering working equipment.
The electricity generated by the tether as it swings through the Earth's magnetic field is expected to have a slowing effect on the space junk, which should, scientists say, pull it into a lower and lower orbit.
Eventually the detritus will enter the Earth's atmosphere, burning up harmlessly long before it has chance to crash to the planet's surface.
NEWS: Space Junk Tracker to Orbit Earth
"The experiment is specifically designed to contribute to developing a space debris cleaning method," said Masahiro Nohmi, associate professor at Kagawa University, who is working with JAXA on the project, told AFP.
Nohmi said a satellite developed by the university is expected to be launched into space on February 28, with the tether aboard.
"We have two main objectives in the trial next month," he said. "First, to extend a 300-meter (1,000-foot) tether in orbit and secondly to observe the transfer of electricity."
ANALYSIS: What Can We Do About the Space Junk Problem?
The actual reeling in of orbiting rubbish will be the objective of future experiments, he said. A spokesman for JAXA said the agency also plans to conduct its own trial on a tether in 2015.
More than 20,000 bits of cast off equipment, including old satellites, pieces of rocket and other fragments are uselessly orbiting the Earth in a band 800-1,400 kilometers (500-900 miles) from the surface of the planet at terrific speed.
Their presence causes problems for space scientists who have to try to prevent them colliding with functioning kit because of the huge damage they can cause.
A graphical representation of the growing space debris problem. Note: Space junk not to scale!
The third Orbital Sciences Corporation Antares rocket cargo run to the space station launches from Pad-0A at NASA's Wallops Flight Facility on Jan. 9, 2014. Orbital is one of two private firms contracted by NASA to resupply the outpost.
READ MORE: Belated Christmas: Orbital Rocket Launches ISS Cargo
The SpaceX Falcon 9 rocket launched from Cape Canaveral Air Force Station at 5:06 p.m. EST. successfully carrying the Thaicom 6 satellite to a parking orbit 55,900 miles above Earth.
SpaceShipTwo's rocket engine burst to life during a successful powered test flight over the Mojave Desert, Calif., on Friday. This comes ahead of the company's plan to see the first suborbital space tourist trips later in 2014.
READ MORE: SpaceShipTwo Aces Third Rocket-Powered Test Flight
A tiny amount of sunlight leaks through a truss-based radiator panel and a primary solar array panel on International Space Station, as seen by an Expedition 39 space station crewmember.
A recent Mastcam photograph by Mars rover Curiosity of damage on one of its aluminum wheels. This week, NASA released images of Curiosity as seen by the orbiting Mars Reconnaissance Orbiter.
READ MORE: NASA Orbiter Spies Curiosity Ripping Up Mars Dust
Color version of the Dec. 11, 2013, observation by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Note the geological variations in the surrounding landscape.
Meanwhile, a decade ago... A panorama of NASA's Mars Exploration Rover Spirit's landing site inside Gusev Crater. Jan. 4 marked the 10 year anniversary since the rover touched down on the red planet.
READ MORE: Spirit's Decade Old Mosaic of Mars is Still Stunning
A X1-class solar flare erupted from AR 1944 on Jan. 7. The flare also triggered a coronal mass ejection (CME) that that was directed toward Earth, but it had minimal impact on Jan. 9. The event, however, delayed the Orbital Sciences Antares rocket launch by two days amid concerns for the high-radiation environment surrounding Earth.
The recommissioned infrared NASA orbiter NEOWISE observed a newly-discovered near-Earth asteroid 2013 YP139.
READ MORE: Recommissioned NEOWISE Discovers Near-Earth Asteroid
Gemini Planet Imager's 'first light' image of Beta Pictoris b, an exoplanet orbiting the star Beta Pictoris. The commissioning of the GRI represents a new era in exoplanetary studies.
READ MORE: New Exoplanet Hunter Directly Images Alien Worlds
Artist conception of Supernova 1987A and its newly discovered dust cloud.
This long-exposure Hubble Space Telescope image of massive galaxy cluster Abell 2744 is the deepest ever made of any cluster of galaxies. This is the first image from Hubble's "Frontier Fields" project.
The nearby spiral galaxy M83 is was revealed in all its glory by this Hubble Space Telescope mosaic. The bright regions shown in the spiral are vey active star forming regions.


text:
The blue social bookmark and publication sharing system.
Log in with your username.
I've lost my password.
Log in with your OpenID-Provider.
David Slater has been fighting for years over who has the copyright to photos taken by monkeys using his camera, and says he's struggling as a result
BibSonomy is offered by the KDE group of the University of Kassel, the DMIR group of the University of Würzburg, and the L3S Research Center, Germany.


text:
|19 Apr 2013
runtime error! R6025 -pure virtual function call???
like the title, what is this and how to fix it?? it happens if i try to go inside a train in rail simulator =( its a C++ error... i tried to read about it on ms site but i didn't get it....
|My System Specs
|20 Apr 2013
Hi there have you tried Uninstalling and then Re installing ?
I would also clean the temp files using Disk Cleanup before Re-Insulation
You could also try running at lower resolution. if it starts you can go back to full screen.
|My System Specs
|20 Apr 2013
|My System Specs
|20 Apr 2013
Hi What version of the software are you using?
Has it ever worked proper on your Windows 7 system ?
|My System Specs
|20 Apr 2013
what software? everything works perfect exept rail simulator 2008... i have tried to install/reinstall C++, new graphic drivers etc, but nothing makes it work
|My System Specs
|20 Apr 2013
Windows 10 Pro X64
peugot, does this link look like the same issue you are having?
Runtime error
Try running CCleaner and clean your registry.
Also wanted to add are you playing Rail Simulator through Origin?
|My System Specs
|21 Apr 2013
|My System Specs
|21 Apr 2013
well yes, but i have tries uninstall and install again, look for updates etc all of that. and no, its not origin, its downloaded from a gameproviders site in my country which have shitty support... all of my other games are working perfect so i wonder what can cause this. i even tried it on my laptop and there it works but its not a very good gaming computer so its not a solution to use that, i'll call it unplayable =( i did a clean reinstall of windows on this pc i have problems on like 2 months ago so there should be ok there aswell.. also did get all c++ needed reinstalled/installed. even graphics driver, physx etc. im lost :S
|My System Specs
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2017, the entire industry are exploring new development models, to seek new growth points. Mahogany furniture industry as an important part of the traditional real economy, we must recognize the qualitative change in the market environment, grasp the pulse of the development of the times. At the beginning of the new year in 2017,[url=http://loungechairsuppliers.com/beach-chairs/1263.html]portable reclining beach chair[/url] Alibaba Group CEO Zhang Yong said: "The economy is no physical and virtual points, but there must be new and old. New real economy is rapidly rising and generate huge social benefits.It can be said that the Chinese people have lived in the new The real economy. "
Furniture industry in the past 2016, and actively explore the "new retail" format, embrace the Internet, to achieve online and offline synchronization, the use of technical means for enterprise intelligence,[url=http://loungechairsuppliers.com/beach-chairs/1340.html]metal bistro chairs manufacturers[/url] based on the expansion of the physical shopping malls, to build an Internet platform to " Home "as the core of the business upstream and downstream cross-border extension. In addition, the opening O2O experience museum, home platform is "new retail" to explore an important attempt. On the mahogany furniture industry, a single store sales model has been unable to meet the consumer form of the upgrade, multi-channel integrated marketing is the future trend.
Young strategy, that is, enterprises to understand the needs of young consumer groups change. Young consumer groups on the demand for furniture products has not only confined to the appearance, price, quality and other traditional factors, the function is becoming one of the main needs of its purchase of furniture. At present,[url=http://loungechairsuppliers.com/beach-chairs/1246.html]sturdy plastic foldable stool for easy storage[/url] the new Chinese is widely welcomed by young consumers, enterprises must understand the aesthetic of consumers in order to design, strategy and other aspects of the adjustment.


text:
The Tour
1.1a The existing events at the following locations will be sanctioned for the 2017 Men's UST Tour.
|Internacional De Skimboard, Santa Cruz, PORTUGAL
|Outer Banks Skim Jam, OBX, NC, USA
|East Coast Championships, Dewey Beach, DE, USA
|FL Skimboarding Pro/Am, Vilano Beach, FL, USA
|26th Ave Skimblast, Santa Cruz, CA, USA
|Balboa Oktoberfest, Newport Beach, CA, USA
|Sununga, Ubatuba, Sao Paulo, BRAZIL
|* 7 Events Total
1.1b The existing events at the following locations will be sanctioned for the 2017 Women's UST Tour.
|East Coast Championships, Dewey Beach, DE, USA
|Skimblast, Santa Cruz, CA USA
|Balboa Oktoberfest, Newport Beach, CA, USA
|* 3 Events Total
Point Scoring – Men's Division
1.2a Each competitor's highest scores at any four of the seven UST sanctioned events will be counted. Competitors may compete at more than four events to attain the highest scores possible.
The point total and point scaling (multiplier) awarded at each event will be modified according to professional participation in that event.
Events with more professional competitors will be awarded more points for first place, and the multiplier used to determine the points granted for successive placements will be higher. The new point scaling system will work as outlined below.
|Professional Entries
|Points For 1st
|Less than 21
|21 – 25
|26 – 30
|31 – 35
|36 – 40
|More than 40
*points table shown for illustrative purposes only. Any calculation errors which are discovered will be replaced with correct calculated values.
Point Scoring – Women's Division
1.2b Each competitor's highest scores at any two of the three UST sanctioned events will be counted. Competitors may compete at more than two events to attain the highest scores possible.
The first place finisher in the women's division shall earn 1000 points toward their UST total. Each successive finisher shall receive 90% of the points of the finisher directly above them. The full point allocation table will be the same as the Men use for events with 26 – 30 competitors.
Results Handling
1.3a If a contest director doesn't deliver full pro results and top 4 amateur results within 10 days, he risks his contest not being counted for that year and future years.
1.3b If a contest director does not deliver his contest results at all, his contest will definitively not be sanctioned by the UST for the following three years. A unanimous vote by the directors is required to waive this automatic three year penalty. After the three year penalty, there is no guarantee that the contest will be re-sanctioned by the UST.
1.3c No points will count for contests with incomplete results. In the case that full professional results are not delivered for whatever reason, partial points for the top placing competitors will not be counted.
Access and Transparency
1.4 Contest directors must grant authorized UST representatives full access at the event for monitoring purposes upon request.
Event Cancellation
1.5 If a contest is cancelled in a given year for any reason short of an Act of God, that contest will need to acquire unanimous support from UST directors to be allowed back on the tour.
1.6 If two or more competitors tie in the results at any particular event the tied riders shall evenly share the points allocated to the positions for which they tied.
If two or more competitors are tied in the final point tally at the end of the UST season, the UST shall attempt to break the tie by counting additional events (including dropped scores). If the tie cannot be broken by this methodology and actual tie will occur and the riders will share the UST placing and any prizes or awards, evenly.


text:
Chris Davis
April 26, 2013 at 11:40AM
George Jones, known as the Cadillac of Country Music because of his vocal range and nuanced phrasing, has died. While looking back over past articles I stumbled across a piece I'd written prior to Jones' 1998 appearance at The Mid-South Fair.
Chris Shaw
April 24, 2013 at 9:35AM
This Friday, Austin, Texas natives Spray Paint play Murphy's in support of their first full-length record. Featuring members of Austin punk bands Dikes of Holland and When Dinosaurs Ruled the Earth, Spray Paint has been gaining steady attention for their debut album on California's SS Records that was released at the beginning of 2013 and fans of off-kilter garage punk a la Britain's Hygiene, or perhaps Memphis' own Sharp Balloons should make plans to attend.
J.D. Reager
April 19, 2013 at 6:54PM
In recent years, the local indie-pop group Star & Micey has seen its stock rise from relative obscurity to one of the most consistently enjoyable and hardest-working acts in town. The group's 2012 E.P. I Can't Wait earned the band rave reviews from both critics and fans, as well as slots on high-profile national music festivals such as the Folk Alliance Conference and South By Southwest.
Greg Akers
April 11, 2013 at 3:01PM
What began as a Twitter rumor and message board material can now be independently confirmed by the Memphis Flyer, from sources with knowledge of the situation: 96X will be returning to the Memphis airwaves. The format change — a re-formatting, if you will — was first reported by Radio Insight yesterday.
Chris Herrington
April 5, 2013 at 1:55PM
Craig Brewer's $5 Cover was the canary in the coal mine, and another MTV production, Savage County, followed. This weekend, a new Memphis-shot web-based film series premieres in the form of Headshop, a series that follows nine characters whose lives intersect around a local headshop where a new designer drug is being sold.
© 2017 Memphis Flyer


text:
|Publication number
|Publication type
|Application number
|Publication date
|Feb 9, 2010
|Filing date
|Dec 21, 2005
|Priority date
|Dec 21, 2005
|Fee status
|Also published as
|Publication number
|Harold Lee, Michael Chaves
|Original Assignee
|Teradata Us, Inc.
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (23), Referenced by (3), Classifications (9), Legal Events (4)
|External Links: USPTO, USPTO Assignment, Espacenet
The invention relates generally to search and retrieval and more particularly to techniques for mapping a physical table to multiple virtual tables.
Modern databases provided a convenient mechanism for enterprises to store and organize their information or data. Generally, logical data or information associated with one aspect of the enterprise is organized within its own independent table. A table includes its own schema or definition and includes a plurality of fields organized within the table as rows and columns.
Query languages permit users to search the database against a single table or against multiple tables for purposes of returning results that comply with the search criteria or search terms. In some cases, the results may be voluminous or may span multiple disparate tables housed in the database.
In such situations, the users often like to issue new searches against the results returned. But, in order for this to be achieved the results have to be defined as a single table within the database. The problem is each result may be associated with an entirely different database table definition. This also necessitates that services of the database perform a join on the different associated table definitions that are included within the results.
One technique to address this entails pre-establishing within the database definitions or schemas for likely combinations of fields that a search may yield by way of results. This may work for a general or popular search on a few different database tables, but it will not work for all possible combinations. Moreover, the permutations associated with various combinations of fields included within the database may not practically be accounted for in predefined table definitions. As a result, often results from a custom search are not available as a unique single table from which the user can continue to search and interact with. This means the user may have to issue more creative searches or be more technically savvy to achieve what he/she originally intended to do with the original search and its subsequent results.
Thus, it can be seen that improved techniques for processing results associated with search queries are desirable.
In various embodiments, techniques for mapping a physical table to multiple virtual tables are provided. In an embodiment, one or more concepts from different physical data store tables are identified for a query search results set. One or more collections of the concepts are then mapped to their own virtual table and a handle to a new results table is returned for further interaction. The new results table joins each of the virtual tables into the new results table.
As used herein a "data store" may include a database, a collection of databases organized as a data warehouse, a directory, a collection of directories, or various combinations of these items. The data store includes a variety of physical tables, each physical table having its own schema or data definition defining its fields, rows, and columns.
Initially, each concept or each collection of concepts in the data store associated with a plurality of same or disparate tables has a single schema or single data definition created for that concept or concept collection within the data store, such that the concept or concept collection appears to be associated with its own independent table. These concept table definitions are referred to as virtual tables.
A concept may be viewed as a logical or business association within the data store. For example, the concept of INDIVIDUAL may include a variety of columns from a same data table or a variety of data tables within a data store; these columns may include CUSTOMER_ID and HOUSEHOLD_ID. A concept may be combined with other concepts as well for purposes of establishing a virtual table. So, the INDIVIDUAL concept may be combined with a STORE concept that includes a single STORE_ID column. In such a case, the INDIVIDUAL concept may be joined with other tables that include the CUSTOMER_ID and HOUSEHOLD_ID columns or the INDIVIDUAL concept may be joined with other tables that include just the STORE_ID column. When a join is achievable via an overlapping column or field between two or more tables then those tables are said to be capable of being mapped with one another.
A concept may also be viewed as a logical collection of one or more fields/columns from the data store. A concept associates portions of a same table or of different tables with one another and provides a logical link between different tables, since the different tables share at least one same field/column with one another. Again, this link permits the tables to be joined within one another.
At 110, the virtual table mapping service identifies one or more concepts that appear in tables returned from a search query. The combined returned tables and their columns or fields appear in the results set from the search query. The columns or fields may be inspected to identify concepts of collections of concepts, which are also identified in the data store as being virtual tables.
It is noted that any particular table within the results set may be associated with a plurality of concepts or virtual table definitions. That is, unlike conventional approaches a single physical table is associated with the teachings herein and below with two or more virtual tables. In fact, the only limit on the number of virtual tables that may be associated with any particular table is the total number of available virtual table definitions housed in the data store.
At 120, the virtual table mapping service maps or associates each concept or collection of concepts identified in the data stores and included within the results set as its own independent virtual table. Each virtual table has its own schema or table definition within the data store.
According to an embodiment, at 121, the virtual table mapping service assembles a number of the virtual tables having similar concepts into a sub graph. At 122, sub graphs are collected as a connected set of sub graphs. The virtual table mapping service then, at 123, submits the set to a table join analysis service to perform a join against the connected set of sub graphs. The table join analysis service may be an existing table join operation that has been modified to handle the set and perform the join against the plurality of sub graphs representing the multiple virtual tables.
At 130, in response to joining the virtual tables, the virtual table mapping service returns a handle to a new results table. The new results table represents the join of the virtual tables; and the handle is returned to a user or an automated application that initially performed the search query against the data store and in response to that search query acquired the results set.
At this point the searcher (user or automated application) may, at 140, perform a new search against the new results table using the handle as a single table reference. The search is performed as a query against the table joined from the connected set of sub graphs, each sub graph includes one or more virtual tables and the virtual tables are derived as concepts included in the tables and identified in the data store by way of virtual table definitions or schemas.
At 141, in response to the search against the joined table a new results set is returned. At 142, the entire processing of the virtual table mapping service may be reiterated a second time to produce another new results table having a new handle. This recursion or iteration may interactively occur, such that the searcher can continue to interact and mine the results.
It is now appreciated, how single results set may be mapped to a plurality of virtual tables and associated with a single referenced table handle. Moreover, a single physical table may be associated with multiple virtual tables. The virtual tables account for the permutations of columns in a searcher's initial results set and are identified as being concepts or collections of concepts having prior data definitions within the data store.
In this manner, there is no need to develop data definitions for a few select results sets or expected tables and then attempting to map those data definitions to a searcher's query results, which has been the conventional approach; rather, the searcher's query results are dynamically mined and collections of existing concepts are formed, connected, and joined into a single results table using existing virtual table definitions housed within the data store.
The joining service prepares a results set from a search query for processing by a table join analysis service. This is done by inspecting the results set for collections of fields that can be associated as concepts and mapped to existing virtual table definitions within a data store.
Collections of identified virtual tables are then organized as sub graphs and the sub graphs organized as a set of connected sub graphs. The reference to the set is then passed to the table join analysis service. The table join analysis service then performs a join for purposes of forming a single results table definition. Furthermore, the joined and single results table may be subsequently used by a searcher for purposes of performing additional queries.
It is within this context that the
At 211, the joining service also identifies a second set of fields associated with a second physical table. Again, the fields and the physical table are identified within the results set of a search query performed. The second set of fields is also associated with one or more second virtual tables.
According to an embodiment, the virtual tables are identified and mapped by acquiring pre-existing virtual table definitions from the data store for each of the sets. This may be done by identifying the first set as being a predefined concept within the data store having predefined first table definitions or first schemas. Similarly, the second set is associated with second table definitions or second schemas within the data store.
At 220, the joining service creates a first sub graph for the first set of fields. This connects in a first sub graph the first set of fields, such that any particular portion may be reached by traversing the first sub graph and all edges derived from the first sub graph.
In a similar manner, at 221, the joining service creates a second sub graph for the second set of fields. Again, this connects the second sub graph the second set of fields, such that any particular portion may be reached by traversing the second sub graph and all edges derived from the second sub graph.
After the first and second sub graphs are derived from the assembled first and second virtual tables, at 230, the joining service organizes the first and second sub graphs as a connect set of sub graphs. That is, at 231, the first and second sub graphs are logically connect via a common field or set of fields appearing somewhere in each of the sub graphs.
At 240, the joining service supplies the set of connected sub graphs to a table joining analysis service via reference to the set as a whole. The table joining analysis service uses that set reference to join the first virtual table and the second virtual table represented within the set of sub graphs.
After the set of sub graphs are joined by the table joining analysis service, at 250, the joining service receives a reference to a single table from the table joining analysis service. This single table and its reference logically refer to the searcher's results set for the searcher's initial search query against the data store.
So, the single table is then used, at 251, by the joining service to return a reference as a new table reference for the results set of the initial query against the data store. That is, the joined virtual tables may be searched as a single table via the new table reference.
It is noted that conventionally such a situation has not been practical or feasible with existing techniques because the approach has been to attempt to predefine the most popular permutations an initial results set may yield from a data store query and create table definitions for those popular permutations. Moreover, conventionally it was deemed infeasible to predefine all possible permutations as data definitions.
These conventional problems are solved with the joining service because the connect set of sub graphs permit the data definition for the results set to be formed from collections of existing virtual table definitions. Thus, all permutations do not have to be predefined; rather they may be derived from collections of virtual table definitions that are connected as a set of sub graphs.
In an embodiment, at 260, the joining service may also map additional fields or collections of fields to additional virtual tables from the initial results set and produce additional sub graphs. These additional sub graphs may also be connected within the set of sub graphs and included in the single joined table and its associated and derived table definition. So, as many virtual tables as are present in the initial results set may be mined from the results set and organized as two or more sub graphs within the connected set.
The virtual table mapping system 300 includes a mapping service 301 and a table join analysis service 302. In some embodiments, the virtual table mapping system 300 may also include a virtual table creation service 303, a search and query service 304, and/or a data store 304. Each of these will now be discussed in turn.
The mapping service 301, during its operation, maps one or more fields of same or different physical tables to its own virtual table definition and virtual table reference. It is noted that a same physical table within the results set may have multiple virtual tables mapped to it. The physical tables and the fields are acquired from a results set of a search query against the data store 305. The mapping service 301 iterates the results set for multiple mappings that establish multiple virtual tables being defined within the results set. Moreover, the mapping service 301 is invoked when a results set is returned.
In an embodiment, the mapping service 301 identifies concepts included within the results set; these concepts represent the logical collections of the fields. Furthermore, the concepts have predefined table definitions within a data store 305. The definition and use of the term concept was described above with respect to the virtual table mapping service represented by the method 100 of the
The mapping service 301 also organizes the virtual tables as a set of connected sub graphs from which any edge or permutation associated with the sub graphs may be derived.
Examples of a mapping service 301 and its operations were presented above with respect to various aspects of the methods 100 and 200 of the
The table join analysis service 302 receives a reference to a set of sub graphs and performs a join on the virtual tables included therein to produce a single reference to a new table. The table join analysis 302 is to treat each of the sub graphs within the set as an independent logical table for purposes of the join.
According to an embodiment, the table join analysis service 302 is implemented as a modified version of an existing table join analysis service, which is adapted to receive sub graphs organized as a connected set reference and to process the join from the sub graphs by traversing edges of the connected set reference.
After the table join analysis service 302 produces the reference to the new table it is supplied to the mapping service 301. The mapping service 301 then supplies the reference to a searcher. The searcher is now able to treat the collection of disparate tables and fields associated with the original results set as a single entity for purposes of further searching and manipulation.
According to an embodiment, the virtual table mapping system 300 may also include a virtual table creation service 303. The virtual table creation service 303 is used to initial populate a data store 305 with the virtual table definitions. The virtual table definitions may be viewed as concepts or as collections of concepts. The virtual table creation service processes in advance of the mapping service 301 and supplies a foundation within the data store 305 for the mapping service 301.
The virtual table mapping system 300 may also include a search and query service 304. The search and query service 304 may be viewed as a data store interface that permits a searcher to construct queries and manipulate the results sets. Moreover, the search and query service 304 permits a searcher (user or automated application) to use the single reference produced from the join of the table join analysis service 302 to search a previously acquired results set from a previous issued query.
It is also noted that the processing of the virtual table mapping system 300 may iterate for as many iterations as the searcher dictates. That is, the searcher may continue to refine and manipulate his results set. In a processing iteration, the results set is mapped to a single table reference by breaking tables included within the results set into collections of mapped virtual tables organized as sub graphs. The sub graphs are then logically linked as a connected set of sub graphs and supplied to the table join analysis service 302.
The virtual table mapping system 300 may also include a data store 305. The data store 305 may be a database, a collection of databases organized as a data warehouse, a directory, a collection of directories, or various combinations of these resources. In an embodiment, the data store 305 is a Teradata� warehouse product or service distributed by NCR. Corporation of Dayton, Ohio.
It is however appreciated that any data store 305 may be modified for purposes of the teachings presented here, without departing from the teachings. Essentially, the data store 305 is the backbone which houses or stores the enterprise data and table definitions/schemas associated with the enterprise data. Moreover, a number of the table definitions/schemas are associated with virtual table definitions while others are associated with physical table definitions.
Searchers issue queries against the data store 305. Any virtual table creation service 303, which may be optionally present, populates the data store 305 with virtual table definitions (concept definitions or collections of concept definitions). The mapping service 301 uses the data store 305 to identify the virtual table definitions from an initial results set. The initial results set is the result of a searcher's query. The table join analysis 302 uses the set of sub graphs produced by the mapping service 301 to derive a table definition for the data store 305 from permutations discovered or derived from within the set of sub graphs.
One now appreciates how a results set from a search query may be organized as a set of virtual tables depicted within a connected set of sub graphs. A join service then joins the sub graphs to a single referenced table. A searcher can use the single table as if it were a single entity for purposes of subsequent search and retrieval operations. Thus, each permutation within results set of a search may be derived and represented within the single table such is not the case with conventional approaches. Also, a single physical table may be mapped or associated with multiple virtual tables within the sub graphs.
Furthermore, the techniques presented herein allow a join service to perform a more efficient join on the tables comprised in the results set because a single physical table may be represented as a plurality of mapped virtual tables.
The above description is illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of embodiments should therefore be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
The Abstract is provided to comply with 37 C.F.R. �1.72(b) and will allow the reader to quickly ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
In the foregoing description of the embodiments, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting that the claimed embodiments have more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Description of the Embodiments, with each claim standing on its own as a separate exemplary embodiment.
|Cited Patent
|Filing date
|Publication date
|Feb 13, 1990
|Aug 31, 1993
|International Business Machines Corporation
|Hybrid technique for joining tables
|Sep 27, 1996
|May 26, 1998
|Bull Hn Information Systems Inc.
|Optimizing table join ordering using graph theory prior to query optimization
|May 8, 1997
|Nov 9, 1999
|The Trustees Of Columbia University In The City Of New York
|System and method for performing joins and self-joins in a database system
|Apr 7, 1997
|Nov 16, 1999
|Informix Software, Inc.
|Method and apparatus for performing a join query in a database system
|Jun 25, 1999
|Sep 3, 2002
|International Business Machines Corporation
|Method, system, and program for performing a join operation on a multi column table and satellite tables
|Mar 7, 2001
|Nov 5, 2002
|International Business Machines Corporation
|System, method, and program for object building in queries over object views
|Jun 15, 2000
|Jan 7, 2003
|Ncr Corporation
|Virtual join index for relational databases
|Dec 17, 2002
|Dec 16, 2003
|Gary L. Sharp
|Database structure having tangible and intangible elements and management system therefore
|Oct 19, 2001
|Sep 14, 2004
|Microsoft Corporation
|Generalized keyword matching for keyword based searching over relational databases
|Oct 19, 2001
|Oct 5, 2004
|Microsoft Corporation
|System for keyword based searching over relational databases
|Feb 26, 2002
|Feb 7, 2006
|International Business Machines Corporation
|Application portability and extensibility through database schema and query abstraction
|Nov 5, 2004
|Jul 18, 2006
|Hitachi, Ltd.
|Data management system and method
|Mar 21, 2003
|Dec 5, 2006
|International Business Machines Corporation
|Real-time aggregation of unstructured data into structured data for SQL processing by a relational database engine
|Sep 17, 2003
|Feb 13, 2007
|Gravic, Inc.
|Asynchronous coordinated commit replication and dual write with replication transmission and locking of target database on updates only
|Sep 27, 2001
|Mar 27, 2003
|Cleghorn Monica Rose
|System and method for processing database queries
|Oct 9, 2002
|Apr 15, 2004
|Lasoo, Inc.
|Information retrieval system and method employing spatially selective features
|Jun 12, 2003
|Dec 16, 2004
|International Business Machines Corporation
|Data query schema based on conceptual context
|Sep 29, 2003
|Mar 31, 2005
|International Business Machines Corporation
|Method, system, and program for predicate processing by iterator functions
|Jun 14, 2005
|Feb 23, 2006
|Matchett Douglas K
|Method and apparatus for organizing, visualizing and using measured or modeled system statistics
|May 1, 2006
|Nov 30, 2006
|Next Software, Inc.
|Object graph editing context and methods of use
|Sep 30, 2005
|Apr 5, 2007
|Microsoft Corporation
|Arbitration of specialized content using search results
|Jan 2, 2007
|Jun 28, 2007
|Inform Technologies, Llc
|Network Service for Providing Related Content
|Nov 8, 2006
|Aug 16, 2007
|Louis Burger
|Managing the execution of a query
|Citing Patent
|Filing date
|Publication date
|Aug 31, 2010
|Jan 1, 2013
|International Business Machines Corporation
|Managing information
|Jul 30, 2010
|Jun 9, 2015
|Sap Se
|Dynamically joined fast search views for business objects
|Jul 30, 2010
|Feb 2, 2012
|Oliver Vossen
|Dynamically Joined Fast Search Views for Business Objects
|U.S. Classification
|707/999.102, 707/637, 707/770
|International Classification
|Cooperative Classification
|European Classification
|Mar 20, 2006
Owner name: NCR CORPORATION, OHIO
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|Fee payment
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Although television shows often portray the perfect family, the reality is that disagreements happen. If your family is struggling to reach agreements and form mutually respectful relationships, creative counseling strategies may help. Team building activities during counseling can teach each person how to work together, identify and accept strengths and weaknesses and process feelings that may be throwing the family dynamic off course.
Map Out a Plan
Time is often an issue when kids are busy with school and parents are working. But time is crucial to reinforce family values. During therapy, families can etch out a calendar full of fun activities and responsibilities. Mark days when all of you can make a meal, complete yard work or take in a movie. Working together to create the calendar and responsibilities at home often fosters respect, according to Marie Hartwell-Walker, editor of PsychCentral.com, in the article "3 Steps to a Closer, Stronger Family."
Toss the Ball
Launch a game of toss the ball with a positive twist to build trust and emphasize the value of teamwork, suggests family therapists Liana Lowenstein and Trudy Post Sprunk in their article "Creative Family Therapy Techniques: Play and Art-Based Activities to Assess and Treat Families," found on Lowenstein's website. For five minutes, have each family member toss a ball while offering a compliment about the other person. After the time limit, launch the game again. This time, each family member should express what they would enjoy doing with the others. The game is designed to boost morale and trust, which can lead to stronger confidence and reliance.
Engage in Art Therapy
Create a masterpiece as a group with art and play-based activities during family counseling, recommends Lowenstein and Sprunk. Your family can draw a family portrait with each person adding a drawing to the final masterpiece. In addition, families can create a clay fixture, Play-Doh structure or build blocks with each person adding to the art project. When family members work together, they may feel less self-conscious about their contributions. In addition, the activity teaches the importance of working together, waiting your turn and relying on each team member.
Family Q & A
In order to work as a team, families need to learn more about how each person thinks. Dig deep into the minds of your family with a question and answer game, suggests Kim Peterson, Texas-based psychotherapist, in the article, "A Simple Game For Building a Stronger Family," on her website. Make a list of random questions, such as "If you were an animal, what would you be and why?" or "What is your ideal vacation and who would you bring?" Choose numbers to indicate which person answers each question or ask all members to volunteer answers to the same question. The activity is designed to help families tune into one another on an emotional level.


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Addicted to Hot Again – G3F – V7
A wonderful collection of brand 20 new poses for G3F and also an optimized version for V7, all with mirrored versions! Total of 80 poses. This pack was made having in mind a special attention to hand posing, eyes positioning and all details that make poses natural and realistic so you can enjoy many hours of great renderings. Always the best for you!
Read more description:


text:
Does the best player in the world actually have anything to improve?
Yes, the reigning regular-season and Finals MVP can indeed grow into an even more destructive force on the basketball court, even with a title in hand. If you compare just the 2011-12 season with previous seasons, James has displayed the work ethic and talent to add skills to his game. So how can he take his game to yet another level?
This two-part series will examine two facets of LeBron James' game -- shooting and free throws -- that if improved even slightly could translate into increased production. The first part tackles shooting, including 3-point shooting, and offers a technical breakdown of what James can do to improve. This installment deals with how James can improve his free throw shooting.


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I knit by hand and according to my own designs, using largely locally sourced natural fibre yarns. My specialty is seamless knitting in the round, whereby an article of clothing is created and shaped in one piece on a set of circular or double-pointed needles.
While I was taught to knit 'flat' as a child, when I returned to knitting as an adult I quickly fell in love with the seamless, circular method. The seamless method of garment construction dates back to the earliest forms of knitting and was traditional in Ireland until the mid-1800s, at which point knitting-for-hire made pieced assembly more practical for groups of women sharing the work.The seamless knitting method, however, continues to hold unique merits. It is better suited to making adjustments in fit and style at various stages of the knitting process. The finished garment feels more comfortably on the body, without seams digging into the skin. Seamless knitting also possesses a distinctive sculptural look that holds a special aesthetc appeal.
In my designs, I use traditional techniques such as cables and basic lace work, as well as a variety of shaping techniques, to create well-tailored, wearable pieces.


text:
Just wanted to give a heads up about a new football prediction site called Betegy.com.
They were kind enough to give me behind the scenes access to their predictions and from there I made a couple of bets last weekend.
They did quite well. They had Fulham Reading to end 2-2 and that sounded about right so I put a few pounds on this. As of the 84th minute everything looked terrific, but of course we scored then they scored and so it didn't happen (I'd gone for 0-0 v Villa the week before so late goals are really getting me at the moment!).
My other bet was on Everton v Liverpool. Betegy had a 2-1 Everton win and again I quite liked this. In the end the game finished 2-2 so that missed as well, but not by much.
This weekend they have Fulham v Everton to finish 1-1 so I might give that a go as well.
With all these things there's a degree of risk – football predictions are a tricky beast at the best of times – but the results look broadly correct. They also do predictions for European leagues. Have a look.


text:
Автор: David Kraemer
Название: The Mind of the Talmud: An Intellectual History of the Bavli
Издательство: Oxford University Press
Год: 1990
Формат: PDF
Размер: 11,1 Мб
Язык: Английский
This critical study traces the development of the literary forms and conventions of the Babylonian Talmud, or Bavli, analyzing those forms as expressions of emergent rabbinic ideology. The Bavli, which evolved between the third and sixth centuries in Sasanian Iran (Babylonia), is the most comprehensive of all documents produced by rabbinic Jews in late antiquity. It became the authoritative legal source for medieval Judaism, and for some its opinions remain definitive today. Kraemer here examines the characteristic preference for argumentation and process over settled conclusions of the Bavli. By tracing the evolution of the argumentational style, he describes the distinct eras in the development of rabbinic Judaism in Babylonia. He then analyzes the meaning of the disputational form and concludes that the talmudic form implies the inaccessibility of perfect truth and that on account of this opinion, the pursuit of truth, in the characteristic talmudic concern for rabbinic process, becomes the ultimate act of rabbinic piety.
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text:
The Secret Garden Trailer (1994)
05 November 1994 Animated, Family
Animated TV-film version of Frances Hodgson Burnett's classic children's story about a spoiled English orphan who lives in India but is transplanted to her uncle's old, mysterious house in England after her parents' deaths. After making friends with a country boy and several animals, who talk here, she discovers many secrets on the grounds, including a locked-up, neglected garden and a locked-up, sickly boy, who turns out to be her cousin.
Watch the official The Secret Garden 1994 trailer in HD below or find more The Secret Garden videos on Vidimovie.


text:
The Georgia Tech Yellow Jackets picked up a big running back commitment today from Travis Custis (Hampton, Ga./Lovejoy).
"I committed today to Georgia Tech," Custis said. "I have been talking to coach (Paul) Johnson for a while. To be honest they showed me the most love. I just felt very comfortable there."
Custis, 6-foot-0 and 207 pounds, also believes he can play both running back positions for coach Johnson and his triple-option attack.
"I think there's a good chance I will be their 'A' and 'B' back positions," Custis said. "I have that kind of versatility. I do know that they like me more as a 'B' back. I think I can play either one. I will just have to get used to playing in a three-point stance if I end up being their 'B' back. But I am a downhill runner anyway so it won't be an issue."
Custis committed to Georgia Tech over scholarship offers from teams like Miami, Mississippi State, Vanderbilt, USF, and Boston College. He's their first commitment for the Yellow Jacket 2013 class.