bluuebunny/crossref_metadata_2025 huggingface dataset:
Atmospheric Circulation and Climatic Variability
Authors: Garreaud René D. , Aceituno Patricio
Published: November 2020

Regional variations in South America’s weather and climate reflect the atmospheric circulation over the continent and adjacent oceans, involving mean climatic conditions and regular cycles, as well as their variability on timescales ranging from less than a few months to longer than a year. Rather than surveying mean climatic conditions and variability over different parts of South America, as provided by Schwerdtfeger and Landsberg (1976) and Hobbs et al. (1998), this chapter presents a physical understanding of the atmospheric phenomena and precipitation patterns that explain the continent’s weather and climate. These atmospheric phenomena are strongly affected by the topographic features and vegetation patterns over the continent, as well as by the slowly varying boundary conditions provided by the adjacent oceans. The diverse patterns of weather, climate, and climatic variability over South America, including tropical, subtropical, and midlatitude features, arise from the long meridional span of the continent, from north of the equator south to 55°S. The Andes cordillera, running continuously along the west coast of the continent, reaches elevations in excess of 4 km from the equator to about 40°S and, therefore, represents a formidable obstacle for tropospheric flow. As shown later, the Andes not only acts as a “climatic wall” with dry conditions to the west and moist conditions to the east in the subtropics (the pattern is reversed in midlatitudes), but it also fosters tropical-extratropical interactions, especially along its eastern side. The Brazilian plateau also tends to block the low-level circulation over subtropical South America. Another important feature is the large area of continental landmass at low latitudes (10°N–20°S), conducive to the development of intense convective activity that supports the world’s largest rain forest in the Amazon basin. The El Niño–Southern Oscillation phenomenon, rooted in the ocean-atmosphere system of the tropical Pacific, has a direct strong influence over most of tropical and subtropical South America. Similarly, sea surface temperature anomalies over the Atlantic Ocean have a profound impact on the climate and weather along the eastern coast of the continent. In this section we describe the long-term annual and monthly mean fields of several meteorological variables.
Copper and Bronze, 3000 BC–1500 BC
Authors: Abulafia David
Published: November 2020

The development of prehistoric societies has always been viewed from one of two perspectives: a diffusionist approach, now largely out of fashion, which attributes the arrival of new styles and techniques to migration and trade; or an emphasis on the factors within a society that fostered change and growth. Alongside the tendency to look for internal explanations of change, interest in the ethnic identity of settlers has faded. Partly this reflects an awareness that easy identification of ‘race’ with language and culture bears no relation to circumstances on the ground: ethnic groups merge, languages are borrowed, important cultural traits such as burial practices mutate without the arrival of newcomers. Equally, it would be an error to see all social change as the result of internal developments merely enhanced by the effects of growing trade: the lightly populated shores and islands of the prehistoric Mediterranean provided broad spaces within which those in search of food, exiled warlords or pilgrims to pagan shrines could create new settlements far from home. If there were earlier settlers, the newcomers intermarried with them as often as they chased them away or exterminated them, and the language of one or the other group became dominant for reasons that are now beyond explanation. The Cyclades became the home of a rich and lively culture, beginning in the early Bronze Age (roughly 3000 BC onwards). The main islands were by now all populated; villages such as Phylakopi on Melos were thriving; on several islands small villages developed out of an original core of a couple of small homesteads. The obsidian quarries were still visited, and copper was available in the western Cyclades, whence it reached Crete; Cycladic products continued to flow outwards, though in quite precise directions: to the southern Aegean, but not, for some reason, northwards, suggesting that the opening of the seas was still partial and dependent on what other regions could offer the Cycladic islanders. The islanders appear to have imported little into their villages; very few eastern products have been found on excavated sites on the Cyclades.
The Triumph of the Tyrrhenians, 800 BC–400 BC
Authors: Abulafia David
Published: November 2020

The importance of the Etruscans does not simply lie in the painted tombs whose lively designs captivated D. H. Lawrence, nor in the puzzle of where their distinctive language originated, nor in the heavy imprint they left on early Rome. Theirs was the first civilization to emerge in the western Mediterranean under the impetus of the cultures of the eastern Mediterranean. Etruscan culture is sometimes derided as derivative, and the Etruscans have been labelled ‘artless barbarians’ by one of the most distinguished experts on Greek art; anything they produced that meets Greek standards is classified as the work of Greek artists, and the rest is discarded as proof of their artistic incompetence. Most, though, would find common cause with Lawrence in praising the vitality and expressiveness of their art even when it breaks with classical notions of taste or perfection. But what matters here is precisely the depth of the Greek and oriental imprint on Etruria, the westward spread of a variety of east Mediterranean cultures, and the building of close commercial ties between central Italy, rarely visited by the Mycenaeans, and both the Aegean and the Levant. This was part of a wider movement that also embraced, in different ways, Sardinia and Mediterranean Spain. With the rise of the Etruscans – the building of the first cities in Italy, apart from the very earliest Greek colonies, the creation of Etruscan sea power, the formation of trading links between central Italy and the Levant – the cultural geography of the Mediterranean underwent a lasting transformation. Highly complex urban societies developed along the shores of the western Mediterranean; there, the products of Phoenicia and the Aegean were in constant demand, and new artistic styles came into existence, marrying native traditions with those of the East. Along the new trade routes linking Etruria to the east came not just Greek and Phoenician merchants but the gods and goddesses of the Greeks and the Phoenicians, and it was the former (along with a full panoply of myths about Olympus, tales of Troy and legends of the heroes) that decisively conquered the minds of the peoples of central Italy.
Cholesterol
Authors: Li Jie Jack
Published: November 2020

The story of statins starts with cholesterol because statins are a class of drugs that reduce low-density lipoprotein (LDL) cholesterol, the “bad” cholesterol. LDL cholesterol, in turn, is a major risk factor for coronary heart disease, the leading cause of death worldwide and projected to remain so through 2025. About 1.5 million Americans suffer heart attacks each year, and heart disease has emerged as the biggest cause of death in the United States, killing 911,000 people in 2003. Before the 1940s, the average lifespan in America was 47 years, and heart disease did not contribute to mortality to a large extent because people often died of infections. Currently, an average American lives to celebrate her 77th birthday. As a consequence, heart-related disease has risen to be the number one killer. Coronary heart disease manifests in many forms: angina, arrhythmia, atrial fibrillation, congestive heart failure, hypertension, atherosclerosis, myocardial infarction (heart attack), and sudden cardiac death. Atherosclerosis, or blockage in arteries, results when a buildup of cholesterol, inflammatory cells, and fibrous tissue called plaques forms on an artery wall. If these plaques rupture, they can block blood flow to critical organs such as the heart or brain and can lead to heart attack or stroke. Despite the many different forms of cardiovascular disease, the molecule cholesterol is a common denominator for most of them. Therefore, in order to understand coronary heart disease, we first need to take a look at the cholesterol molecule. According to Roman mythology, Janus is the guardian of portals and patron of beginnings and endings. Just like the two-faced Roman god, cholesterol is a double-edged sword for the human body. On the one hand, it is an essential building block for many crucial ingredients the body needs. On the other hand, it can be lethal when it forms plaques on the surface of the arteries and subsequently causes coronary heart disease. Make no mistake, cholesterol is vital to our existence. It is most abundant in our brains—23% of total body cholesterol resides there, making up 1/10th of the solid substance of the brain.
Baycol, Crestor, and Cholesterol Drugs beyond Statins
Authors: Li Jie Jack
Published: November 2020

In 2001, the National Heart, Lung, and Blood Institute, a division of the National Institutes of Health, released new guidelines for the treatment of hypercholesterolemia. These guidelines called for patients with an average risk of coronary heart disease to reduce their LDL-cholesterol levels to less than 130 mg/dL; for those at high risk, the target is less than 100 mg/dL; and for the highest risk patients, the target is less than 70 mg/dL. The new guidelines nearly tripled the number of Americans who stood to benefit from drug therapy to get their lower cholesterol levels—to 36 million from 13 million. Statins had already become the drug of choice for cholesterol control. Statin awareness was further raised in the wake of former President Bill Clinton’s well-publicized heart attack in September 2004 after he stopped taking Zocor. Increasingly, new data demonstrated the benefits of reducing cholesterol levels even further than physicians had been advocating. The sales of statins therefore skyrocketed, reaching $21 billion in 2004 and $22 billion in 2005. Just like everything else, not all statins are created equal, a point clearly demonstrated by the story of Baycol. No medication, not even a nonprescription drug like aspirin or acetaminophen that you buy over-the-counter, is 100% safe. Whether or not you realize it, whenever you take a drug, you are weighing the potential benefits against the possibility that the medicine can hurt you. This analysis is what the experts call the risk–benefit profile of a drug. Four months after Lipitor was launched for sale, the FDA approved cerivastatin, the sixth statin, for use in lowering cholesterol in 1997. Germany’s Bayer A. G. sold it under the trade name Baycol and Lipobay (for the free acid form) until it was forced to withdraw it from the market in August 2001. Baycol was discovered by a group of Bayer scientists led by medicinal chemist Rolf Angerbauer and biologist Hilmar Bischoff in Wuppertal, Germany, in the late 1980s. It was only the second optically pure synthetic statin on the market (Lipitor was the first).
The Vestibular and Optokinetic Systems
Authors: Wong Agnes
Published: November 2020

The vestibulo-ocular and optokinetic reflexes are the earliest eye movements to appear phylogenetically. The vestibulo-ocular reflex (VOR) stabilizes retinal images during head motion by counter-rotating the eyes at the same speed as the head but in the opposite direction. Information about head motion passes from the vestibular sensors in the inner ear to the VOR circuitry within the brainstem, which computes an appropriate eye velocity command. The eyes, confined in their bony orbits, normally do not change position, and their motion relative to the head is restricted to a change in orientation. However, the head can both change position and orientation relative to space. Thus, the function of the VOR is to generate eye orientation that best compensates for changes in position and orientation of the head. Because the drive for this reflex is vestibular rather than visual, it operates even in darkness. To appreciate the benefits of having our eyes under vestibular and not just visual control, hold a page of text in front of you, and oscillate it back and forth horizontally at a rate of about two cycles per second. You will find that the text is blurred. However, if you hold the page still and instead oscillate your head at the same rate, you will be able to read the text clearly. This is because when the page moves, only visual information is available. Visual information normally takes about 100 msec to travel from the visual cortices, through a series of brain structures, to the ocular motoneurons that move the eyes. This delay is simply too long for the eyes to keep up with the oscillating page. However, when the head moves, both vestibular and visual information are available. Vestibular information takes only about 7–15 msec to travel from the vestibular sensors, through the brainstem, to the ocular motoneurons. With this short latency, the eyes can easily compensate for the rapid oscillation of the head. Thus, damages to the vestibular system often cause oscillopsia, an illusion of motion in the stationary environment, especially during head movements.
The Saccadic System
Authors: Wong Agnes
Published: November 2020

Saccades are fast conjugate eye movements that move both eyes quickly in the same direction, so that the image of an object of interest is brought on the foveae. Saccades can be made not only toward visual targets, but also toward auditory and tactile stimuli, as well as toward memorized targets. Saccades can be generated reflexively, and they are responsible for resetting the eyes back to the mid-orbital position during vestibulo-ocular or optokinetic stimulation. Saccades need to be fast to get the eyes on the target as soon as possible. They also need to be fast because our eyes act like cameras with slow shutters—vision is so blurred during saccades that the eyes have to move quickly to minimize the time during which no clear image is captured on the foveae. Indeed, saccades are the fastest type of eye movements, and they are among the fastest movements that the body can make. Saccade speed is not under voluntary control but depends on the size of the movement, with larger saccades attaining higher peak velocities. It has been estimated that we make more than 100,000 saccades per day. The burst neuron circuits in the brainstem provide the necessary motor signals to the extraocular muscles for the generation of saccades. There is a division of labor between the pons and the midbrain, with the pons primarily involved in generating horizontal saccades and the midbrain primarily involved in generating vertical and torsional saccades. However, because eye movements are a component of cognitive and purposeful behaviors in higher mammals, the process of deciding when and where to make a saccade occurs in the cerebral cortex. Not only does the cortex exert control over saccades through direct projections to the burst neuron circuits, it also acts via the superior colliculus. The superior colliculus is located in the midbrain and consists of seven layers: three superficial layers and four intermediate/ deep layers. The three superficial layers receive direct inputs from both the retina and striate cortex, and they contain a retinotopic representation of the contralateral visual hemifield.
The Vergence System
Authors: Wong Agnes
Published: November 2020

Vergence eye movements shift the gaze point between near and far, such that the image of a target is maintained simultaneously on both foveae. Unlike other eye movement systems, vergence movements are disjunctive, meaning that the eyes move in opposite directions. To move from a far to a near target, the eyes converge (i.e., rotate toward the nose) so that the lines of sight of the two eyes intersect at the target. To aim at a target farther away, the eyes diverge (i.e., rotate toward the temples). When the target is located at optical infinity, the lines of sight are parallel. During deep sleep, deep anesthesia, and coma, the eyes diverge beyond parallel, indicating that eye alignment is normally actively maintained by the brain because the orbits, in which the eyeballs are located, are divergent. The vergence system is believed to be relatively new evolutionarily. Just as a new version of computer software tends to have bugs, perhaps it is for this reason that vergence is the last of the eye movement systems to reach full development in children, that it is often the first system to be affected by fatigue, alcohol, and other drugs, and that defective vergence is a common cause of strabismus and diplopia. Vergence eye movements are very slow, lasting 1 sec or longer. One reason for this may be that vergence, unlike saccades, is driven by visual feedback, which normally takes at least 80 msec. Another reason may be that the speed of vergence movements is limited by how fast the lenses change shape (accommodation) and how fast the pupils constrict. There may simply be no advantage for vergence to take place quickly and then wait for the lenses and pupils to catch up. The triad of convergence, accommodation, and pupillary constriction constitutes the near triad. The two most important stimuli for vergence are retinal image blur and retinal disparity. If the retinal image of an object is blurred, the target is either too near or too far away.
Saccadic Dyskinesia, Other Involuntary Eye Movements, and Gaze Deviations
Authors: Wong Agnes
Published: November 2020

■ A small saccade of 0.5–3° that takes the eye away from fixation, followed by a saccade that returns the eye back to fixation after about 200 msec (i.e., presence of intersaccadic interval during which visual feedback occurs) ■ So named because of its appearance in eye movement tracings ■ Normal subjects often have square wave jerks (SWJ), but the rate is only 4–6 per minute. ■ Pathologic SWJ occurs at a rate of >15 per minute. ■ Cerebellar diseases Square wave jerks result from damage of projections from the frontal eye field, rostral pole of the superior colliculus, and the central mesencephalic reticular formation to the omnipause cells in the pons. If symptomatic, SWJ may be treated with methylphenidate, diazepam, phenobarbital, or amphetamines. ■ Burst of saccades with defective steps of innervation (i.e., stepless saccades) ■ Conjugate or monocular Saccadic pulses are associated with multiple sclerosis. Saccadic pulses result from damage of omnipause cells or the neural integrator.
Ocular Motor Disorders Caused by Lesions in the Cerebellum
Authors: Wong Agnes
Published: November 2020

The vestibulocerebellum consists of the flocculus, ventral paraflocculus, nodulus, and uvula. ■ The flocculus receives inputs from the vestibular nucleus and nerve, nucleus prepositus hypoglossi (NPH), inferior olivary nucleus, cell groups of the paramedian tracts (PMT), nucleus reticularis tegmenti pontis (NRTP), and mesencephalic reticular formation. ■ The ventral paraflocculus receives inputs from contralateral pontine nuclei. ■ Project to ipsilateral superior and medial vestibular nuclei, and the y-group ■ Receive input from the medial and inferior vestibular nuclei, vestibular nerve, NPH, and inferior olivary nucleus ■ Project to the vestibular nuclei ■ The oculomotor vermis consists of parts of the declive, folium, tuber, and pyramis. ■ Receives inputs from the inferior olivary nucleus, vestibular nuclei, NPH, paramedian pontine reticular formation (PPRF), NRTP, and dorsolateral and dorsomedial pontine nuclei ■ Projects to the caudal fastigial nucleus ■ Stimulation of the Purkinje cells in the dorsal vermis elicits contralaterally directed saccades and smooth pursuit ■ Receives inputs from the dorsal vermis, inferior olivary nucleus, and NRTP ■ Decussates and projects via the uncinate fasciculus of the brachium conjunctivum to the contralateral PPRF, rostral interstitial nucleus of the medial longitudinal fasciculus, nucleus of the posterior commissure, omnipause neurons in nucleus raphe interpositus, the mesencephalic reticular formation, and superior colliculus ■ Neurons in the fastigial oculomotor region (FOR) fire during both ipsilateral and contralateral saccades. 1. The contralateral FOR neurons burst before the onset of saccade, and the onset of firing is not correlated with any property of the saccade. 2. Conversely, the time of onset for neurons in the ipsilateral FOR varies, with bursts occurring later for larger saccades. 3. Thus, the difference in time of onset between contralateral and ipsilateral FOR activity encodes the amplitude of saccades (i.e., the larger the difference in time of onset, the larger the saccade amplitude). Eye movement abnormalities in uncinate fasciculus lesion include hypometric ipsilesional saccades and hypermetric contralesional saccades (“contrapulsion”). Arnold-Chiari malformation is a malformation of the medullary–spinal junction with herniation of intracranial contents through the foramen magnum. The three types are illustrated in the figure below.
Nuclear and Infranuclear Ocular Motor Disorders
Authors: Wong Agnes
Published: November 2020

Binocular diplopia is usually caused by strabismus, whereas monocular diplopia is usually caused by ocular diseases. Incomitant diplopia is usually caused by an acquired strabismus resulting from abnormal innervation or mechanical restriction. The oculomotor (third) nerve: ■ Innervates the medial rectus, superior rectus, inferior rectus, inferior oblique, and levator palpebrae muscles ■ Carries parasympathetic fibers to the iris sphincter and the ciliary body. ■ Common causes of third nerve palsy: Adults: aneurysms, vascular disease (including ischemia, diabetes, hypertension, and inflammatory arteritis), trauma, migraine Children: birth trauma, accidental trauma, neonatal hypoxia, migraine The third nerve originates from the oculomotor nucleus complex, which lies at the ventral border of the periaqueductal gray matter in the midbrain. The nerve fascicle passes ventrally through the medial longitudinal fasciculus, the tegmentum, the red nucleus, and the substantia nigra, and finally emerges from the cerebral peduncle to form the oculomotor nerve trunk, which lies between the superior cerebellar and posterior cerebral arteries. The nerve then passes through the subarachnoid space, running beneath the free edge of the tentorium. It continues lateral to the posterior communicating artery and below the temporal lobe uncus, where it runs over the petroclinoid ligament. It pierces the dura mater at the top of the clivus to enter the cavernous sinus. Within the cavernous sinus, the nerve runs along the lateral wall of the sinus together with the trochlear nerve and the ophthalmic (V1) and maxillary (V2) divisions of the trigeminal nerve. As it leaves the cavernous sinus, it divides into the superior and inferior divisions, which pass through the superior orbital fissure, and enters the orbit within the annulus of Zinn. Within the orbit, the smaller superior division runs lateral to the optic nerve and ophthalmic artery and supplies the superior rectus and levator palpebrae muscles. The larger inferior division supplies the medial rectus, inferior rectus, and inferior oblique muscles, as well as the iris sphincter and ciliary body.
Bad Company: The Business of Toxicity
Authors: Griep Mark A. , Mikasen Marjorie L.
Published: November 2020

In the movies, chemical companies maximize profits by poisoning their customers, workers, neighbors, and the environment, or they terrorize or outright kill the heroic insider who becomes a whistleblower. English professor Phillip Lopate argued in the New York Times that movies about business in general present a cartoon view of corporate structure (usually there isn’t one), making them the “fantasy villain,” a nearly faceless evil represented in the narrative by a “wall of Suits” (Lopate 2000). Business professor Ribstein goes further and asserts that the overwhelmingly negative view of business in American film narratives is fueled by filmmakers who feel their artistic vision is constrained by profit-making capitalists (Ribstein 2005). Ribstein begins his argument with a summary of nine movies about “Evil Corporations.” He doesn’t appear to realize that seven of them were companies that handle or produce chemicals: The China Syndrome (1979), Silkwood (1983), The Fugitive (1993), A Civil Action (1998), The Insider (1999), Erin Brockovich (2000), and Mission: Impossible II (2000). All of these films, and many others, were considered for inclusion in this chapter but, as the fastest growing category of chemistry in the movies, only two from this evil seven made it into the present chapter: Silkwood (1983) and Erin Brockovich (2000). The evil chemical company theme plays out in several ways. In the deeply satiric comedy Kids in the Hall: Brain Candy (1998), the pharmaceutical company’s happiness drug provides a foundation upon which the comedy troupe bases their humor. This chemical gravitas also lends weight to a number of fictional dramas that explore the theme of toxicity, such as One Man (1977), I Love Trouble (1994), and The Constant Gardener (2005). The company presidents in these movies murder, or hire thugs to murder, the individuals who choose to expose the toxicity of their products. Evil chemical companies are found in “based on a true story” dramas such as in Silkwood (1983), Erin Brockovich (2000), and Bhopal Express (2001). Knowing that the story is based on true tales of toxic chemicals lends considerable weight to these story lines.
Evaluation Models
Authors: Lee P.J.
Published: November 2020

The initial step in the evaluation of any petroleum resource is the identification of an appropriate geological population that can be delineated through subsurface study or basin analysis. A geological population represents a natural population and possesses a group of pools and/or prospects sharing common petroleum habitats. A natural population can be a single sedimentation model, structural style, type of trapping mechanism or geometry, tectonic cycle, stratigraphic sequence, or any combination of these criteria. Reasons for adopting these criteria in the definition of a geological model are the following: • The geological population will be defined clearly and its associated resource can readily be estimated. • Geologists can adopt known play data for future comparative geological studies. • Geological variables of a natural population can be described by probability distributions (e.g., the lognormal distribution). Statistical concepts such as the superpopulation concept can be applied to geological models so that, for specific plays, an estimate of undiscovered pool sizes can be made. Figure 2.1 illustrates various sedimentary environments (tidal flat, lagoon, beach, and patch reef) that can be used as geological models in resource evaluation. Each of these models has its own distinguishing characteristics of source, reservoir, trapping mechanism, burial and thermal history of source beds, and migration pathway. In resource evaluation, to ensure the integrity of statistical analysis, each of these should be treated as a separate, natural population. Therefore, the logical steps in describing a play are (1) identify a single sedimentation model and (2) examine subsequent geological processes. Geological processes such as faulting, erosion, folding, diagenesis, biodegradation, thermal history of source rocks, and migration history might provide a basis for further subdivisions of the model. In some cases, two or more populations might be considered mistakenly as a single population because of a lack of understanding of the subsurface geology. If the resulting mixed population were to have two or more modes in its distribution, this could have an impact on resource evaluation results.
Evaluating Conceptual Plays
Authors: Lee P.J.
Published: November 2020

A conceptual play has not yet been proved through exploration and can only be postulated from geological information. An immature play contains several discoveries, but not enough for discovery process models (described in Chapter 3) to be applied. The amount of data available for evaluating a conceptual play can be highly variable. Therefore, the evaluation methods used are related to the amount and types of data available, some of which are listed in Table 5.1. Detailed descriptions of these methods are beyond the scope of this book. However, an overview of these and other methods will be presented in Chapter 7. This chapter deals with the application of numerical methods to conceptual or immature plays. For immature plays, discoveries can be used to validate the estimates obtained. In this chapter, the Beaverhill Lake play and a play from the East Coast of Canada are examined. A play consists of a number of pools and/or prospects that may or may not contain hydrocarbons. Therefore, associated with each prospect is an exploration risk that measures the probability of a prospect being a pool. Estimating exploration risk in petroleum resource evaluation is important. Methods for quantifying exploration risks are described later. Geological factors that determine the accumulation of hydrocarbons include the presence of closure and of reservoir facies, as well as adequate seal, porosity, timing, source, migration, preservation, and recovery. For a specific play, only a few of these factors are recognized as critical to the amount of final accumulation. Consequently, if a prospect located within a sandstone play, for example, were tested, it might prove unsuccessful for any of the following reasons: lack of closure, unfavorable reservoir facies, lack of adequate source or migration path, and/or absence of cap rock. The frequency of occurrence of a geological factor can be measured from marginal probabilities. For example, if the marginal probability for the presence-of-closure factor is 0.9, there is a 90% chance that prospects drilled will have adequate closure. For a prospect to be a pool, the simultaneous presence of all the geological factors in the prospect is necessary. This requirement leads us to exploration risk analysis.
Fourier Transforms in Probability, Random Variables and Stochastic Processes
Authors: Marks II Robert J
Published: November 2020

In this Chapter, we present application of Fourier analysis to probability, random variables and stochastic processes [1089, 1097, 1387, 1329]. Arandom variable, X, is the assignment of a number to the outcome of a random experiment. We can, for example, flip a coin and assign an outcome of a heads as X = 1 and a tails X = 0. Often the number is equated to the numerical outcome of the experiment, such as the number of dots on the face of a rolled die or the measurement of a voltage in a noisy circuit. The cumulative distribution function is defined by FX(x) = Pr[X ≤ x]. (4.1) The probability density function is the derivative fX(x) = d /dxFX(x). Our treatment of random variables focuses on use of Fourier analysis. Due to this viewpoint, the development we use is unconventional and begins immediately in the next section with discussion of properties of the probability density function.
Noise and Error Effects
Authors: Marks II Robert J
Published: November 2020

Exact interpolation using the cardinal series from unaliased samples assumes that (a) the values of the samples are known exactly, (b) the sample locations are known exactly (c) an infinite number of terms are used in the series, and (d) sampling is performed at a sufficiently fast rate. Deviation from these requirements results in interpolation error due to (a) data noise (b) jitter (c) truncation and (d) aliasing respectively. The perturbation to the interpolation from these sources of error is the subject of this chapter. If noise is superimposed on sample data, the corresponding interpolation will be perturbed. In this section, the nature of this perturbation is examined. The effect of data noise on continuous sampling interpolation is treated in Section 10.3.1.2. The multidimensional case is the topic of Section 8.10.2. Suppose that the signal we sample is corrupted by real additive zero mean wide sense stationary noise, ξ (t).
Management of Periocular Neoplasms
Authors: Kersten Robert C.
Published: November 2020

Epithelial malignancy of the eyelid is a common problem, representing about 14% of skin cancers in the head and neck region. The goals when treating any skin cancer are complete elimination of the tumor and minimal sacrifice of normal adjacent tissues. These concepts are of paramount importance when treating periocular epithelial malignancies because of the complex nature of the periocular tissues and their critical function in protecting the underlying globe, as well as the increased risk that recurrent tumor in this area poses. Many modalities have been advocated, by a variety of medical practitioners, for the treatment of epithelial malignancies in the periocular region. There are two key considerations in selecting a treatment for skin cancers. The first is that the selected modality must be capable of eradicating all tumor cells to which it is applied. The second is that some mechanism must exist to ensure that it is applied to all the existing tumor cells. Because tumors of the lid margins and canthi often exhibit slender strands and shoots of cancer cells that may infiltrate beyond the clinically apparent borders of the neoplasm, appropriate monitoring to ensure that the treatment modality reaches all of the cancer cells is essential. Numerous studies have demonstrated that clinical judgment of tumor margins is inadequate, significantly underestimating the area of microscopic tumor involvement. The introduction of frozen-section control to document adequacy of tumor excision marked a major advancement in the treatment of eyelid malignancies and now represents the standard of care. Any treatment modality that does not use microscopic monitoring of tumor margins must instead encompass a wider area of adjacent normal tissue in hopes that any microscopic extensions of tumor will fall within this area. The purpose of this chapter is to explore alternative methods of periocular cancer treatment. Mohs micrographic technique is a refinement of frozen-section control of tumor borders that, by mapping tumor planes, allows a three-dimensional evaluation of tumor margins rather than the two-dimensional examination provided by routine frozen section. The modality was initiated by Frederick E. Mohs, MD, in 1936.
Rejuvenation of the Forehead and Eyebrows
Authors: Seiff Stuart , Seiff Bryan
Published: November 2020

The eyes and upper face impart more emotion than any other part of the human body and can communicate temperament through a variety of complex movements and expressions. The influence of the eyebrow on facial anatomy is subtle but critical in establishing mood as determined by facial expression. Upward-slanting eyebrows suggest surprise or sadness, downward-slanting eyebrows denote anger, flat eyebrows hanging over the eyes suggest fatigue, and eyebrows with a proper arch suggest happiness. Concepts of facial beauty continue to evolve over time, yet certain aesthetic principles invariably define the youthful brow and upper face. The head of the brow should begin at a point directly above the alae of the nose, and the tail of the brow should end on a line drawn from the alae of the nose through the lateral canthus. Classical aesthetic principles held that women have eyebrows with a high, graceful arch, accompanied by a deep superior sulcus and well-defined lid crease. The head of the brow began 1 to 2 mm above the supraorbital rim and the lateral third was elevated up to 1 cm above the rim, with the high point of the arch directly above the lateral aspect of the limbus. Current fashion seems to prefer flatter brows with a subtle upward slanting of the brow tail, rather than a high, accentuated arch. The tail of the brow thins as it elevates laterally. Fullness of the brow tissue and a less shallow superior sulcus has also become en vogue, reflecting the overall trend toward facial fullness as a sign of youthfulness. Men tend to have a straighter brow that lies at or slightly above the orbital rim, with a shallow superior sulcus and a more subtle lid crease. As the face ages, thinning skin and tissue laxity diminish the youthful appearance of the brow and upper eyelid. The eyebrows become ptotic, resulting in vertical redundancy of the upper lid skin. The drooping brow and inelastic skin combine to cause upper eyelid tissue to drape over the lid margin, often obstructing the superior visual field.
Translating Identity-Based Motivation to Intervention: Pathways to Success from School to Jobs and Life
Authors: Oyserman Daphna
Published: November 2020

In this chapter I describe the school-to-jobs intervention, a brief inter¬vention that translates the components of identity-based motivation (IBM) into a testable, usable, feasible, and scalable intervention for use in schools and other settings to improve academic outcomes. To develop the intervention, I took the core IBM principles and translated them into a framework and set of activities that have coherence and meaning. These core principles, as detailed in Chapter 1, are that identities, strategies, and interpretations of difficulty matter when they come to mind and seem relevant to the situation at hand. Because thinking is for doing, context matters, and identities, strategies, and interpretations of difficulty can be dynamically constructed given situational constraints and affordances. Therefore the framework and set of activities I developed were sensitive to the context in which education and educational success or failure occurs, the processes by which children succeed or fail to attain their school-success goals, and the action children need to take if they are to succeed. The intervention was fully tested twice (Oyserman, Bybee, & Terry, 2006; Oyserman, Terry, & Bybee, 2002), using random assignment to control (school as usual) and intervention conditions so that it would be possible to know whether the effects were due to the intervention and not to other differences in the children themselves. Importantly, the tested intervention was manualized and fidelity to both manual and underlying theorized process was also tested. In these ways, the intervention stands as a model for development. STJ is currently being used in England and in Singapore. Each country gives the intervention its own name to fit the context. This chapter is divided into three parts. In the first part, I outline the choices I made in developing the intervention. In the second part, I outline the sequenced activities that constitute the intervention (they are detailed in the manual that forms Chapter 4). In the third part, I describe the evidence that the intervention succeeded in changing academic outcomes and that changes occurred through the process predicted by IBM.
General Effects of Pediatric Diseases on Cognition and Behavior
Authors: Hysing Mari , Lundervold Astri J.
Published: November 2020

In this chapter, pediatric diseases are defined as “illnesses that affect a person for an extended period of time, often for life, and that require medical care attention above and beyond the normal requirements for a child or adolescent” (American Academy of Pediatrics 1993). The prevalence of such chronic illnesses has steadily increased over the past 20–30 years (Downs et al. 2001; Vincer et al. 2006; Marelli et al. 2007), with estimated rates ranging from below 1% to 44% depending on the definition, method, and sample included in the different studies (van der Lee et al. 2007). Several theoretical frameworks and models have been presented to explain how diagnosis-specific effects and generic factors across disorders affect cognition and behavior. The transactional stress and coping model (TSC) is one of the most cited theories on psychological adaption in children with a chronic illness, encompassing both specific and generic effects (Thompson and Gustafson 1996). Dennis (2000) has presented a similar model of factors affecting cognitive outcome in chronically ill children. The models describe how disease-related variables interact with child characteristics, developmental level, family resources, and peer relationships, and provide a useful framework to the present chapter. Several epidemiological and clinical studies have documented that children with pediatric diseases have an increased risk of emotional and behavioral problems (Lavigne and Faier-Routman 1992; Glazebrook et al. 2003; Hysing et al. 2007). Symptoms of internalizing and externalizing disorders are frequently found across the diseases but illness-specific manifestations also exist. Externalizing symptoms of hyperactivity and social problems are most often shown by children with neurological disorders (Rodenburg et al. 2005), while the rate of emotional problems has been reported to be especially high in children with asthma (Vila et al. 2003). Peer interaction and social functions are often affected in children with pediatric disorders. Investigations of the impact of social functioning is a growing research field in pediatric psychology, as part of a general trend in developmental psychology that focuses on close peer relationship as a moderator of nonoptimal functioning (Bukowski and Adams 2005; Burt et al. 2008).
Cognitive and Psychiatric Manifestations of Childhood-Onset Systemic Lupus Erythematosus
Authors: Levy Deborah M. , Ross Gail S.
Published: November 2020

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies directed against multiple organ systems. Individuals with SLE may have disease of only one organ system or of many organ systems at one time during a “flare” of disease activity. Systemic lupus erythematosus is characterized by multiple flares and remissions, and flares may lead to end-organ damage. The diagnosis of SLE is generally made by fulfilling four out of 11 of the American College of Rheumatology (ACR) 1997 Revised Classification Criteria for SLE (Hochberg 1997). Although the 1997 revised criteria have not been validated, the earlier 1982 criteria (Tan et al. 1982) have a sensitivity of 96% and specificity of 100%in childhood-onsetSLE(cSLE) (Ferraz et al. 1994). See Table 3.1 for these criteria. Systemic lupus erythematosus has a prevalence rate of 500 per million persons in the U.S. population (Klippel 1997) but may be as high as 130 per 100,000 persons (Uramoto et al. 1999). Approximately 15% of all SLE has its onset in childhood (prior to 18 years of age). Systemic lupus erythematosus occurs more commonly in non-Caucasians, with greater severity of SLE in children and adult Latino and African Americans than in non-Latino Caucasians (Michet et al. 1979).The female predominance of SLE in adulthood (10:1 female-to-male ratio) is less pronounced in childhood, and the ratio prior to puberty is more likely to be 5:1 or even 3:1.The majority of cSLE cases have onset in the peripubertal age period (10–15 years), which continues to suggest a link between estrogen and other hormones on the development of SLE. Childhood-onset SLE differs from adult-onset SLE in that the frequency of renal disease is higher, and the incidence and prevalence of neuropsychiatric SLE (NPSLE) is probably greater (Tucker et al. 1995; Sibbit et al. 2002). Children require aggressive immunosuppression, which on a dose per kilogram of body weight is generally higher than that required by an adult to treat a similar disease manifestation. Immunosuppression often includes corticosteroids. At least in adults, corticosteroids do not appear to cause cognitive impairment (Carbette et al. 1986; Denburg et al. 1997; Carlomagno et al. 2000).
Fragile X: A Family of Disorders
Authors: Mastergeorge Ann M. , Au Jacky
Published: November 2020

Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability known, and it is the most common single gene disorder associated with autism (Belmonte and Bourgeron 2006; Reddy 2005). It is caused by the lack or deficiency of the FMR1 protein, FMRP (Loesch et al. 2004b). The typical physical features of FXS include prominent ears, hyperextensible finger joints, flat feet, soft skin, and in adolescence and adulthood large testicles (macroorchidism) and a long face (Hagerman 2002b). The behavioral features include poor eye contact, hyperarousal to stimuli, anxiety, hyperactivity, attention deficit, impulsivity, hand stereotypies (such as hand biting and hand flapping), and social deficits including autism and autism spectrum disorder (ASD) (Budimirovic et al. 2006; Clifford et al. 2007; Hall et al. 2008b; Hatton et al. 2006b; Sullivan et al. 2007b). Fragile-X syndrome was first reported by Lubs (1969) in two brothers who had intellectual disability and the appearance of a marker X chromosome, which is a fragile site on their X chromosome. It was later detected that this fragile site on the X chromosome only occurred when the chromosomes were studied in a folate-deficient tissue culture media (Sutherland 1977). Therefore cytogenetic studies were utilized to document cases of FXS throughout the 1980s until the Fragile X Mental Retardation 1 gene (FMR1) was discovered in 1991 (Verkerk et al. 1991). The FMR1 gene was found to have a trinucleotide (CGG) repeat sequence at the 5’ untranslated region, with the normal range later determined to be up to 44 repeats, a gray zone of 45–54 repeats, a premutation of 55–200 repeats, and a full mutation range of more than 200 repeats (Maddalena et al. 2001). Those individuals with the full mutation have a deficit or absence of the FMR1 protein (FMRP) that causes the physical, behavioral, and cognitive features of FXS (Loesch et al. 2004b). Females with the full mutation have another X chromosome that is producing FMRP, depending on the activation ratio (AR) or the percentage of cells that have the normal X chromosome as the active X chromosome.
Neurocognitive Outcomes in Sickle Cell Disease
Authors: Armstrong F. Daniel , Pavlakis Steven
Published: November 2020

Sickle cell disease (SCD) is associated with a range of serious complications, including painful episodes, acute chest syndrome, stroke, splenic sequestration, overwhelming bacterial sepsis, and a host of other less frequent complications that impair quality of life and threaten long-term survival (National Institutes of Health [NIH] 2002). More than 98% of all children born in the United States are tested for SCD as part of state newborn screening programs, making it possible to identify infants who are at risk for these many complications of SCD (Centers for Disease Control and Prevention 2009). It is estimated that about 72,000–80,000 individuals of all ages are living with SCD in the United States, a large number of whom will experience cognitive complication at some point in their lives. Nearly 2 million carry sickle trait but do not have the clinical manifestations of the disease. Approximately 1 in 500 infants of African descent and one in 36,000 of Hispanic descent are born with SCD in the United States each year (National Heart, Lung, and Blood Institute (NHLBI), NIH 2009). While the cognitive complications of cerebrovascular infarction (stroke) have long been recognized, research over the last two decades has shown that cognitive functioning in both children and adults can be impaired for many reasons other than stroke. This chapter describes the underlying structural and biological mechanisms that lead to cognitive impairment, the cognitive outcomes associated with SCD, and emerging pharmacologic, behavioral, and educational intervention strategies to address the cognitive needs of this population. Sickle cell disease describes a group of hereditary hemoglobinopathies that have in common the presence of an abnormal hemoglobin variant known as sickle hemoglobin (HbS). The homozygous condition (HbSS) is also the most severe, and is known as sickle cell anemia. Although there are numerous other variations of sickle hemoglobinopathy, the most common include HbSβthal° and HbSC. Under oxidative stress, the sickle hemoglobin causes erythrocytes to collapse into rigid sickle-shaped molecules, with a significant reduction in oxygen-carrying capacity (NIH 2002).