Children born preterm are at risk for adverse outcome, including visual impairment. We examined the relationship between neonatal DTI and sVEP in children born preterm to determine whether visual ...outcomes are related to early measurements of brain microstructure.
Subjects were born at <34 weeks gestation and imaged before term-equivalent age. DTI fiber tracking was used to delineate the optic radiations and measure tract-specific average FA, D(av), and parallel and transverse diffusivity. Visual-evoked response amplitudes were measured as a function of spatial frequency, contrast, and vernier offset size with sVEP at 6-20 months after birth. The association between DTI and sVEP was assessed by using the Spearman correlation coefficient and linear regression for repeated measures.
Nine children with 15 scans were included. The peak response amplitudes for spatial frequency sweeps were associated with increasing FA and decreasing D(av) and transverse diffusivity (P ≤ .006) but not with parallel diffusivity (P = 1). There was only modest association with the swept contrast condition and no detectable association with the vernier offset sweeps.
Microstructure of the optic radiations measured shortly after birth is associated with quantitatively measured responses elicited by moderate-to-high contrast spatiotemporal gratings in infancy. These findings are in keeping with studies showing a relationship between brain microstructure and function. While the clinical impact is not known, quantitative neuroimaging of white matter may ultimately be important for predicting outcome in preterm neonates.
The Advanced Along-Track Scanning Radiometer (AATSR) was launched on Envisat in March 2002. The AATSR instrument is designed to retrieve precise and accurate global sea surface temperature (SST) ...that, combined with the large data set collected from its predecessors, ATSR and ATSR-2, will provide a long term record of SST data that is greater than 15 years. This record can be used for independent monitoring and detection of climate change. The AATSR validation programme has successfully completed its initial phase. The programme involves validation of the AATSR derived SST values using in situ radiometers, in situ buoys and global SST fields from other data sets. The results of the initial programme presented here will demonstrate that the AATSR instrument is currently close to meeting its scientific objectives of determining global SST to an accuracy of 0.3
K (one sigma). For night time data, the analysis gives a warm bias of between +0.04
K (0.28
K) for buoys to +0.06
K (0.20
K) for radiometers, with slightly higher errors observed for day time data, showing warm biases of between +0.02 (0.39
K) for buoys to +0.11
K (0.33
K) for radiometers. They show that the ATSR series of instruments continues to be the world leader in delivering accurate space-based observations of SST, which is a key climate parameter.
Background:
Juvenile xanthogranuloma (JXG) is an uncommon, usually uncomplicated disease of childhood. Ocular involvement, however, can result in glaucoma and blindness if left untreated. The ...incidence of ocular complications and how best to screen for their occurrence is unknown.
Objective:
We attempted to ascertain management and referral practices among ophthalmologists and dermatologists and to characterize the risk for ocular complications in children with JXG.
Methods:
A total of 431 dermatologists and 438 ophthalmologists were surveyed. In addition, the literature was reviewed.
Results:
The response rates were 28% (dermatologists) and 44% (ophthalmologists). Most believed screening was important, but referral and surveillance practices varied widely. The survey incidence of ocular complications in patients with cutaneous JXG was approximately 0.3% (7 of 2371). The literature incidence was 0.4% (1 of 260). Children at maximum risk were 2 years of age or younger, had multiple skin lesions, and had newly diagnosed JXG.
Conclusion:
Ophthalmologic screening of patients with JXG should be particularly targeted to patients with risk factors of multiple skin lesions, new diagnosis, and age of 2 years or younger.
The Enigma was a cryptographic (enciphering) machine used by the German military during WWII. The German navy changed part of the Enigma keys every other day. One of the important cryptanalytic ...attacks against the naval usage was called Banburismus, a sequentiai Bayesian procedure (anticipating sequential analysis) which was used from the sorine of 1941 until the middle of 1943. It was invented mainlv bv A. M. Turina and was perhaps the first important sequential Bayesian IE is unnecessab to describe it here. Before Banburismus could be started on a given day it was necessary to identifv which of nine 'biaram' (or 'diaraph') tables was in use on that day. In Turing's approach to this identification hk had io istimate the probabilities of certain 'trigraphs'. rrhese trigraphs were used. as described below. for determinine the initial wheel settings of messages). For estimatidg the probabilities, Turing inventedin important special case o the nonparametric (nonhypermetric) Empirid Bayes method independently of Herbert Robbins. The techniaue is the sumxisine form of Emdrical Baves in which a physical prior is assumed to eist but no apbroxiGate functional fonn is assumed for it.
Various compromises that have occurred between Bayesian and non-Bayesian methods are reviewed. (A citation is provided that discusses the inevitability of compromises within the Bayesian approach.) ...One example deals with the masses of elementary particles, but no knowledge of physics will be assumed.
Incompatibilities on the sex chromosomes are important in the evolution of hybrid male sterility, but the evolutionary forces underlying this phenomenon are unclear. House mice (Mus musculus) ...lineages have provided powerful models for understanding the genetic basis of hybrid male sterility. X chromosome-autosome interactions cause strong incompatibilities in M. musculus F1 hybrids, but variation in sterility phenotypes suggests a more complex genetic basis. In addition, XY chromosome conflict has resulted in rapid expansions of ampliconic genes with dosage-dependent expression that is essential to spermatogenesis. Here, we evaluated the contribution of XY lineage mismatch to male fertility and stage-specific gene expression in hybrid mice. We performed backcrosses between two house mouse subspecies to generate reciprocal Y-introgression strains and used these strains to test the effects of XY mismatch in hybrids. Our transcriptome analyses of sorted spermatid cells revealed widespread overexpression of the X chromosome in sterile F1 hybrids independent of Y chromosome subspecies origin. Thus, postmeiotic overexpression of the X chromosome in sterile F1 mouse hybrids is likely a downstream consequence of disrupted meiotic X-inactivation rather than XY gene copy number imbalance. Y chromosome introgression did result in subfertility phenotypes and disrupted expression of several autosomal genes in mice with an otherwise nonhybrid genomic background, suggesting that Y-linked incompatibilities contribute to reproductive barriers, but likely not as a direct consequence of XY conflict. Collectively, these findings suggest that rapid sex chromosome gene family evolution driven by genomic conflict has not resulted in strong male reproductive barriers between these subspecies of house mice.
Information on the reproductive behaviour and population structure of female hawksbill turtles, Eretmochelys imbricata, is necessary to define conservation priorities for this highly endangered ...species. Two hypotheses to explain female nest site choice, natal homing and social facilitation, were tested by analyzing mtDNA control region sequences of 103 individuals from seven nesting colonies in the Caribbean and western Atlantic. Under the social facilitation model, newly mature females follow older females to a nesting location, and subsequently use this site for future nesting. This model generates an expectation that female lineages will be homogenized among regional nesting colonies. Contrary to expectations of the social facilitation model, mtDNA lineages were highly structured among western Atlantic nesting colonies. These analyses identified at least 6 female breeding stocks in the Caribbean and western Atlantic and support a natal homing model for recruitment of breeding females. Reproductive populations are effectively isolated over ecological time scales, and recovery plans for this species should include protection at the level of individual nesting colonies.
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