Prader-Willi syndrome: are there population differences?

A 15 1/2-year-old black female with features consistent with the Prader-Willi syndrome is reported. This is the second case report of a black individual and the first case of a black female with the Prader-Willi syndrome. There is an apparent paucity of blacks reported with this condition. Whether this difference is a true difference or represents under-reporting is not known. We urge reporting of individuals representing other racial groups with this disorder and suggest population studies to determine the incidence as well as the true population difference in the Prader-Willi syndrome

Craniofacial variation and growth in the Prader-Labhart-Willi syndrome

A study of anthropometric variation and craniofacial growth in individuals with the Prader-Labhart-Willi syndrome (PLWS) illustrates the utility of anthropometry in clinical evaluation and research. Anthropometric measurements, including head length and breadth, minimum frontal diameter, and head circumference, were obtained on 38 PLWS individuals (21 with chromosome 15 deletions) with an age range from 2 weeks to 39 years. No anthropometric differences were found between the two chromosome subgroups. A relative deceleration in the growth of certain craniofacial dimensions (head circumference and length) is suggested by the negative correlations between age and Z-scores for the measurements. Raw values for minimum frontal diameter and head breadth were near or below the 5th percentile curve, while almost all values for head length and circumference fell within normal limits. The data support suggestions that dolichocephaly be considered an early diagnostic feature of PLWS. Furthermore, the status of narrow bifrontal diameter as a major feature of PLWS is confirmed

Quantum entanglement between a nonlinear nanomechanical resonator and a microwave field

We consider a theoretical model for a nonlinear nanomechanical resonator coupled to a superconducting microwave resonator. The nanomechanical resonator is driven parametrically at twice its resonance frequency, while the superconducting microwave resonator is driven with two tones that differ in frequency by an amount equal to the parametric driving frequency. We show that the semi-classical approximation of this system has an interesting fixed point bifurcation structure. In the semi-classical dynamics a transition from stable fixed points to limit cycles is observed as one moves from positive to negative detuning. We show that signatures of this bifurcation structure are also present in the full dissipative quantum system and further show that it leads to mixed state entanglement between the nanomechanical resonator and the microwave cavity in the dissipative quantum system that is a maximum close to the semi-classical bifurcation. Quantum signatures of the semi-classical limit-cycles are presented.Comment: 36 pages, 18 figure

Synchronization of many nano-mechanical resonators coupled via a common cavity field

Using amplitude equations, we show that groups of identical nano-mechanical resonators, interacting with a common mode of a cavity microwave field, synchronize to form a single mechanical mode which couples to the cavity with a strength dependent on the square sum of the individual mechanical-microwave couplings. Classically this system is dominated by periodic behaviour which, when analyzed using amplitude equations, can be shown to exhibit multi-stability. In contrast groups of sufficiently dissimilar nano-mechanical oscillators may lose synchronization and oscillate out of phase at significantly higher amplitudes. Further the method by which synchronization is lost resembles that for large amplitude forcing which is not of the Kuramoto form.Comment: 23 pages, 11 figure

An Anglo-Saxon execution cemetery at Walkington Wold, Yorkshire

This paper presents a re-evaluation of a cemetery excavated over 30 years ago at Walkington Wold in east Yorkshire. The cemetery is characterized by careless burial on diverse alignments, and by the fact that most of the skeletons did not have associated crania. The cemetery has been variously described as being the result of an early post-Roman massacre, as providing evidence for a ‘Celtic’ head cult or as an Anglo-Saxon execution cemetery. In order to resolve the matter, radiocarbon dates were acquired and a re-examination of the skeletal remains was undertaken. It was confirmed that the cemetery was an Anglo-Saxon execution cemetery, the only known example from northern England, and the site is set into its wider context in the paper

La tempête de verglas : une occasion d’étudier les effets du stress prénatal chez l’enfant et la mère

Depuis plusieurs années, des études ont démontré que les événements stressants pendant la grossesse affectent le niveau de développement neurologique, de même que le fonctionnement cognitif et psychologique ultérieurs de l'enfant. Par exemple, Mednick (1997) a examiné l'impact d'un important séisme survenu en Chine sur le développement intellectuel et psychologique d'enfants à naître. Vingt-trois ans plus tard, des différences significatives dans le fonctionnement intellectuel, la dépression et la taille de certaines régions du cerveau ont été constatées chez ce groupe en comparaison aux enfants du groupe témoin. Des événements de moindre envergure, tels un divorce ou la perte d'emploi durant la grossesse, peuvent également augmenter l'incidence des complications obstétricales et avoir un impact sur le fonctionnement neurologique du bébé, son poids à la naissance et la circonférence de sa tête. Le décès du père ou l'exposition à un désastre naturel durant la grossesse ont été associés à la dépression, à la schizophrénie et à la criminalité à l'âge adulte. Divers effets adverses reliés aux événements stressants ont aussi été notés chez les primates. L'ensemble de ces études suggèrent que le second trimestre de la grossesse constitue une période critique pendant laquelle les événements stressants peuvent affecter le développement du foetus. Des contraintes méthodologiques nuisent actuellement à la recherche sur le stress prénatal maternel. Les études sur des animaux offrent d'excellents contrôles des environnements prénatal et postnatal. Cependant, les résultats de ces études sont difficilement applicables à l'humain à cause de la présence chez ce dernier, de nombreux facteurs de risque ou de protection absents chez les animaux. De plus, on ne peut assigner les stresseurs de façon aléatoire, dans les études sur les effets des événements de vie pendant la grossesse humaine. En effet, les traits de personnalité de la mère peuvent être transmis certes génétiquement mais également au niveau du développement. Par ailleurs, les enfants d'une mère avec de telles difficultés de personnalité sont exposés à plus d'événements de vie prénatale. D'autre part, la majorité des études sur l'humain ont une variance restreinte car il faut un très vaste échantillon de femmes enceintes pour garantir un nombre suffisant de sujets ayant vécu des événements de vie majeurs. Finalement, les études rétrospectives démontrant un lien entre un risque élevé de schizophrénie ou de dépression et des événements prénataux n'incluent pas de mesures prises sur le champ de la gravité objective ou de la manifestation biologique du stress. Nous présentons ici une revue de littérature portant sur le stress prénatal suivie d'une discussion sur comment la tempête de verglas de 1998 pourrait être utilisée pour faire la lumière sur des questions telles que les mécanismes par lesquels le stress prénatal exerce une influence sur la santé mentale du foetus.Over the last several years, studies have shown that stressful experiences during the pregnancy can predict levels of neurological development, as well as cognitive and psychological functioning, during childhood and adulthood. For example, Mednick (1997) has been studying the effects of a major earthquake in China on the psychological and intellectual development of the unborn child. Twenty-three years after the quake, significant differences have been found between the earthquake group and a control group born one year later in terms of intellectual functioning, depression, and the size of certain brain regions. Less severe events, such as a divorce or job loss during the pregnancy, may also increase the risk of obstetric complications and may have an effect on the baby's neurological well being, weight and head circumference at birth. Death of the baby's father during the pregnancy and natural disasters have both been associated with increased rates of depression, schizophrenia and criminality in adulthood. Several of these same effects have been found in studies of prenatal stress in non-human primates. Many of these studies suggest that the second trimester of pregnancy is a particularly critical period during which stressful events may compromise development of the fetus. Methodological constraints limit research on prenatal maternal stress. Animal studies are able to control for pre- and postnatal environments. However, animal studies have limited generalizability to humans for whom numerous risk and protective factors are in operation. Studies of human pregnancies cannot randomly assign subjects to stress conditions. Maternal personality and temperament may be associated with characteristics of a woman's child not only through genetic transmission of personality, but possibly also through differential exposure to difficult life conditions which may, in part, be self-imposed. In addition, studies of prenatal life events in humans have severely restricted variance; very large samples of women must be screened to identify even small numbers of women who have experienced major life events during the pregnancy. Finally, follow-back studies which show an association between prenatal events and later rates of mental illness, do not include timely evaluations of actual rates of exposure to the event, nor the pregnant woman's subjective or biological reactions to the event. In this paper, we present a review of the literature on prenatal maternal stress followed by a discussion of how the January 1998 Québec ice storm could be used to study the mechanisms by which prenatal stress may influence mental health outcomes in the unborn child.Desde hace varios años, estudios han demostrado que los hechos estresantes durante el embarazo afectan el grado de desarrollo neurológico, como posteriormente el funcionamiento cognoscitivo y psicológico del niño. Por ejemplo, Mednick (1997) examinó el impacto de un terremoto importante occurrido en China en el desarrollo intelectual y psicológico del futuro niño. Veintitres años después, diferencias significativas fueron constatadas en en funcionamiento intelectual, la depresión y la dimensión de ciertas regiones del cerebro en este grupo, comparativamente a un grupo testigo. Hechos de menor envergadura como el divorcio o la pérdida del empleo durante el embarazo pueden igualmente aumentar la incidencia de las complicaciones obstétricas y tener un impacto en el funcionamiento neurológico del bebé, su peso en el nacimiento y la circunferencia de la cabeza. La muerte del padre o la exposición a un desastre natural durante el embarazo han sido asociados a la depresión, la esquizofrenia y la criminalidad en la edad adulta. Diversos efectos adversos ligados a hechos estresantes también han sido notados en los primates. El conjunto de estos estudios sugieren que el segundo trimestre del embarazo constituye un período crítico durante el cual los eventos estresantes pueden afectar el desarrollo del feto. Impedimentos metodológicos afectan actualmente la investigación sobre el estrés perinatal materno. Los estudios con animales ofrecen excelentes controles del medio perinatal y postnatal. Sin embargo los resultados de estos estudios dificilmente son aplicables al ser humano a causa de la presencia de numerosos factores de riesgo o de protección, ausentes en los animales. Además, en los estudios sobre los efectos de los eventos de vida durante el embarazo no se puede asignar estresores de forma aleatoria. En efecto, los rasgos de personalidad de la madre pueden ser transmitidos genéticamante, pero también en el curso del desarrollo. Entre otras, los niños de una madre con determinadas dificultades de personalidad están expuestos a más hechos perinatales de vida. Por otra parte, la mayoría de los estudios sobre el humano varían poco puesto que se necesita un amplio muestreo de mujeres embarazadas que garantice un número suficiente de sujetos que hayan vivido eventos de vida mayores. Para terminar, los estudios retrospectivos demuestran una relación entre el alto riesgo de esquizofrenia o de depresión y los hechos perinatales no incluyen la toma rápida de medidas sobre la gravedad objetiva o sobre la manifestación biológica del estres. Nosotros presentamos aquí una revista de la literatura que aborda el estres perinatal, seguida de una discusión sobre cómo la tempestad de hielo de 1998 podría se utilizada para aclarar sobre interrogantes tales los mecanismos por los cuales el estres perinatal ejerce una influencia en la salud mental de feto

Roles of Education and IQ in Cognitive Reserve in Parkinson's Disease-Mild Cognitive Impairment.

Background/aimsThe role of cognitive reserve in Parkinson's disease (PD)-mild cognitive impairment (MCI) is incompletely understood.MethodsThe relationships between PD-MCI, years of education, and estimated premorbid IQ were examined in 119 consecutive non-demented PD patients using logistic regression models.ResultsHigher education and IQ were associated with reduced odds of PD-MCI in univariate analysis. In multivariable analysis, a higher IQ was associated with a significantly decreased odds of PD-MCI, but education was not.ConclusionThe association of higher IQ and decreased odds of PD-MCI supports a role for cognitive reserve in PD, but further studies are needed to clarify the interaction of IQ and education and the impact of other contributors such as employment and hobbies

Metacarpophalangeal pattern profile analysis in fragile X syndrome

We analyzed the metacarpophalangeal pattern profile (MCPP) on 18 male individuals from 16 families with fragile X—fra (X), or Martin-Bell—syndrome and calculated a mean syndrome profile. Fourteen of 18 individuals with fra (X) syndrome had significant positive correlations which indicated clinical homogeneity. Discriminant analysis of individuals with fra (X) syndrome compared with a sample of normal individuals produced a correct classification rate of 88% based on a function of 3 MCPP variables that may provide a useful tool in screening individuals for the fra (X) syndrome. Discriminant and correlation analyses of individuals with Sotos sequence and individuals with fra (X) syndrome did not identify MCPP similarities. Therefore, there was no MCPP evidence in our study of patients with Sotos sequence and fra (X) chromosome expression

Maternal effects on anogenital distance in a wild marmot population

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