Circadian circuits in humans:White matter microstructure predicts daytime sleepiness

The suprachiasmatic nucleus of the hypothalamus is the chief circadian pacemaker in the brain, and is entrained to day-night cycles by visual afferents from melanopsin containing retinal ganglion cells via the inferior accessory optic tract. Tracer studies have demonstrated efferents from the suprachiasmatic nucleus projecting to the paraventricular nucleus of the hypothalamus, which in turn project to first-order sympathetic neurons in the intermedio-lateral grey of the spinal cord. Sympathetic projections to the pineal gland trigger the secretion of the sleep inducing hormone melatonin. The current study reports the first demonstration of potential sympathopetal hypothalamic projections involved in circadian regulation in humans with in vivo virtual white matter dissections using probabilistic diffusion tensor imaging (DTI) tractography. Additionally, our data shows a correlation between individual differences in white matter microstructure (measured with fractional anisotropy) and increased daytime sleepiness [measured with the Epworth Sleepiness Scale (ESS, Johns, 1991)]. Sympathopetal connections with the hypothalamus were virtually dissected using designated masks on the optic chiasm, which served as an anatomical landmark for retinal fibres projecting to the suprachiasmatic nucleus, and a waypoint mask on the lateral medulla, where hypothalamic projections to the sympathetic nervous system traverse in humans. Sympathopetal projections were demonstrated in each hemisphere in twenty-six subjects. The tract passed through the suprachiasmatic nucleus of the hypothalamus and its trajectory corresponds to the dorsal longitudinal fasciculus traversing the periaqueductal region and the lateral medulla. White matter microstructure (FA) in the left hemisphere correlated with high scores on the ESS, suggesting an association between circadian pathway white matter microstructure, and increased daytime sleepiness

An Energy and Performance Exploration of Network-on-Chip Architectures

In this paper, we explore the designs of a circuit-switched router, a wormhole router, a quality-of-service (QoS) supporting virtual channel router and a speculative virtual channel router and accurately evaluate the energy-performance tradeoffs they offer. Power results from the designs placed and routed in a 90-nm CMOS process show that all the architectures dissipate significant idle state power. The additional energy required to route a packet through the router is then shown to be dominated by the data path. This leads to the key result that, if this trend continues, the use of more elaborate control can be justified and will not be immediately limited by the energy budget. A performance analysis also shows that dynamic resource allocation leads to the lowest network latencies, while static allocation may be used to meet QoS goals. Combining the power and performance figures then allows an energy-latency product to be calculated to judge the efficiency of each of the networks. The speculative virtual channel router was shown to have a very similar efficiency to the wormhole router, while providing a better performance, supporting its use for general purpose designs. Finally, area metrics are also presented to allow a comparison of implementation costs

Removal of Chloroform from Drinking Water

The overall objective of this investigation was to evaluate via laboratory experiments the technical feasibility of reducing trihalomethane levels in drinking water. Special attention was directed at the removal of chloroform since: (a) it is the only trihalomethane which has been shown to be carcinogenic in animal tests; and (b) this compound generally comprises the largest fraction of the total trihalomethane content of chlorinated waters in Kentucky. Trihalomethanes are present in municipal drinking waters due to the reaction of free chlorine with naturally occurring compounds, collectively called precursors . A variety of treatment processes and potential modifications (or additions) to existing treatment facilities were evaluated for precursor and trihalomethane removal. In-plant modifications which could be implemented at existing treatment facilities were evaluated initially since they require a minimal amount of capital expenditure and could be implemented within a short time frame. Unit treatment operations studied for precursor removal included: settling, alum-polymer coagulation, precipitive softening, ion-exchange softening. rapid sand filtration, adsorption with both powdered and granular activated carbon. and treatment with ozone and chlorine dioxide. A survey of the trihalomethane levels at fifteen of Kentucky\u27s larger water utilities was completed. While not a part of the original scope of this project, this information should assist local water utilities and health officials in assessing the State\u27s current trihalomethane situation. Additional field studies were completed at two of Kentucky\u27s water utilities to provide plant-scale data on: (a) the effectiveness of a shallow bed of granular activated carbon in removing trihalomethanes; (b) the reduction of trihalomethane levels by moving the point of pre-chlorination; and (c) the reduction in the formation of trihalomethanes during precipitive softening by converting free chlorine to chloramines prior to the addition of lime and soda ash. Results from both field and laboratory studies indicate that water utilities can markedly reduce the level of trihalomethanes currently in drinking water. Such reductions can be made by a variety of approaches which include alteration of disinfection practices, in-plant modifications to enhance precursor removal, and addition of new treatment processes such as carbon adsorption, ozonation and so forth. Only granular activated carbon adsorption appeared capable of completely removing precursor compounds and thereby eliminate the subsequent formation of trihalomethanes upon chlorination

Wide Attention Is The Way Forward For Transformers?

The Transformer is an extremely powerful and prominent deep learning architecture. In this work, we challenge the commonly held belief in deep learning that going deeper is better, and show an alternative design approach that is building wider attention Transformers. We demonstrate that wide single layer Transformer models can compete with or outperform deeper ones in a variety of Natural Language Processing (NLP) tasks when both are trained from scratch. The impact of changing the model aspect ratio on Transformers is then studied systematically. This ratio balances the number of layers and the number of attention heads per layer while keeping the total number of attention heads and all other hyperparameters constant. On average, across 4 NLP tasks and 10 attention types, single layer wide models perform 0.3% better than their deep counterparts. We show an in-depth evaluation and demonstrate how wide models require a far smaller memory footprint and can run faster on commodity hardware, in addition, these wider models are also more interpretable. For example, a single layer Transformer on the IMDb byte level text classification has 3.1x faster inference latency on a CPU than its equally accurate deeper counterpart, and is half the size. We therefore put forward wider and shallower models as a viable and desirable alternative for small models on NLP tasks, and as an important area of research for domains beyond this

Causes of ant sting anaphylaxis in Australia: the Australian Ant Venom Allergy Study

Objective: To determine the Australian native ant species associated with ant sting anaphylaxis, geographical distribution of allergic reactions, and feasibility of diagnostic venom-specific IgE (sIgE) testing. Design, setting and participants: Descriptive clinical, entomological and immunological study of Australians with a history of ant sting anaphylaxis, recruited in 2006-2007 through media exposure and referrals from allergy practices and emergency physicians nationwide. We interviewed participants, collected entomological specimens, prepared reference venom extracts, and conducted serum sIgE testing against ant venom panels relevant to the species found in each geographical region. Main outcome measures: Reaction causation attributed using a combination of ant identification and sIgE testing. Results: 376 participants reported 735 systemic reactions. Of 299 participants for whom a cause was determined, 265 (89%; 95% CI, 84%-92%) had reacted clinically to Myrmecia species and 34 (11%; 95% CI, 8%-16%) to green-head ant (Rhytidoponera metallica). Of those with reactions to Myrmecia species, 176 reacted to jack jumper ant (Myrmecia pilosula species complex), 18 to other jumper ants (15 to Myrmecia nigrocincta, three to Myrmecia ludlowi) and 56 to a variety of bulldog ants, with some participants reacting to more than one type of bulldog ant. Variable serological cross-reactivity between bulldog ant species was observed, and sera from patients with bulldog ant allergy were all positive to one or more venoms extracted from Myrmecia forficata, Myrmecia pyriformis and Myrmecia nigriceps. Conclusion: Four main groups of Australian ants cause anaphylaxis. Serum sIgE testing enhances the accuracy of diagnosis and is a prerequisite for administering species- specific venom immunotherapy

Modular instrument for a haptically-enabled robotic surgical system (HeroSurg)

To restore the sense of touch in robotic surgical systems, a modular force feedback-enabled laparoscopic instrument is developed and employed in a robotic-assisted minimally invasive surgical system (HeroSurg). Strain gauge technology is incorporated into the instrument to measure tip/tissue lateral interaction forces. The modularity feature of the proposed instrument makes it interchangeable between various tip types of different functionalities, e.g., cutter, grasper, and dissector, without losing force sensing capability. Series of experiments are conducted and results are reported to evaluate force sensing capability of the instrument. The results reveal mean errors of 1.32 g and 1.98° in the measurements of tip/tissue load magnitude and direction across all experiments, respectively

Evaluation of variants in the selectin genes in age-related macular degeneration

<p>Abstract</p> <p>Background</p> <p>Age-related macular degeneration (AMD) is a common disease of the elderly that leads to loss of the central visual field due to atrophic or neovascular events. Evidence from human eyes and animal models suggests an important role for macrophages and endothelial cell activation in the pathogenesis of AMD. We sought to determine whether common ancestral variants in genes encoding the selectin family of proteins are associated with AMD.</p> <p>Methods</p> <p>Expression of E-selectin, L-selectin and P-selectin was examined in choroid and retina by quantitative PCR and immunofluorescence. Samples from patients with AMD (n = 341) and controls (n = 400) were genotyped at a total of 34 SNPs in the <it>SELE</it>, <it>SELL </it>and <it>SELP </it>genes. Allele and genotype frequencies at these SNPs were compared between AMD patients and controls as well as between subtypes of AMD (dry, geographic atrophy, and wet) and controls.</p> <p>Results</p> <p>High expression of all three selectin genes was observed in the choroid as compared to the retina. Some selectin labeling of retinal microglia, drusen cores and the choroidal vasculature was observed. In the genetic screen of AMD versus controls, no positive associations were observed for <it>SELE </it>or <it>SELL</it>. One SNP in <it>SELP </it>(rs3917751) produced p-values < 0.05 (uncorrected for multiple measures). In the subtype analyses, 6 SNPs (one in <it>SELE</it>, two in <it>SELL</it>, and three in <it>SELP</it>) produced p-values < 0.05. However, when adjusted for multiple measures with a Bonferroni correction, only one SNP in <it>SELP </it>(rs3917751) produced a statistically significant p-value (p = 0.0029).</p> <p>Conclusions</p> <p>This genetic screen did not detect any SNPs that were highly associated with AMD affection status overall. However, subtype analysis showed that a single SNP located within an intron of <it>SELP </it>(rs3917751) is statistically associated with dry AMD in our cohort. Future studies with additional cohorts and functional assays will clarify the biological significance of this discovery. Based on our findings, it is unlikely that common ancestral variants in the other selectin genes (<it>SELE </it>and <it>SELL</it>) are risk factors for AMD. Finally, it remains possible that sporadic or rare mutations in <it>SELE</it>, <it>SELL</it>, or <it>SELP </it>have a role in the pathogenesis of AMD.</p