858 research outputs found
Spectrometry method of estimation of photosynthesis efficiency of light sources
Розроблено методику та проведено оцінку фотосинтезної ефективності ламп різного типу на основі їх спектрального розподілу випромінювання. Дана методика передбачає перехід від відносних одиниць до енергетичних. Проведено порівняльну оцінку фотосинтезної ефективності джерел світла, фотосинтезний потік яких записувався у вигляді суми потоків в окремих областях спектра. Показано, що поряд з високою енергетичною ефективністю володіють хорошою фітовіддачею лампи типу ДРИ1000-2, ДРИ2000-2М, ДНаТ-400 та ДРФ1000.In the paper on the basis radiation spectral distribution the method of photosynthesis efficiency estimation has been developed. In the method the conversion of relative units into power ones has been proposed. The estimation has been carried out for different of lamps basing on a variety of criteria. It has been shown that, except of high energy efficiency, the lamps ДРИ1000-2, ДРИ2000-2М, ДНаТ-400 аnd ДРФ1000 are characterized by good photoefficiency
Loss of vesicular dopamine release precedes tauopathy in degenerative dopaminergic neurons in a Drosophila model expressing human tau.
While a number of genome-wide association studies have identified microtubule-associated protein tau as a strong risk factor for Parkinson's disease (PD), little is known about the mechanism through which human tau can predispose an individual to this disease. Here, we demonstrate that expression of human wild-type tau is sufficient to disrupt the survival of dopaminergic neurons in a Drosophila model. Tau triggers a synaptic pathology visualized by vesicular monoamine transporter-pHGFP that precedes both the age-dependent formation of tau-containing neurofibrillary tangle-like pathology and the progressive loss of DA neurons, thereby recapitulating the pathological hallmarks of PD. Flies overexpressing tau also exhibit progressive impairments of both motor and learning behaviors. Surprisingly, contrary to common belief that hyperphosphorylated tau could aggravate toxicity, DA neuron degeneration is alleviated by expressing the modified, hyperphosphorylated tau(E14). Together, these results show that impairment of VMAT-containing synaptic vesicle, released to synapses before overt tauopathy may be the underlying mechanism of tau-associated PD and suggest that correction or prevention of this deficit may be appropriate targets for early therapeutic intervention
Asymmetric ephaptic inhibition between compartmentalized olfactory receptor neurons.
In the Drosophila antenna, different subtypes of olfactory receptor neurons (ORNs) housed in the same sensory hair (sensillum) can inhibit each other non-synaptically. However, the mechanisms underlying this underexplored form of lateral inhibition remain unclear. Here we use recordings from pairs of sensilla impaled by the same tungsten electrode to demonstrate that direct electrical ("ephaptic") interactions mediate lateral inhibition between ORNs. Intriguingly, within individual sensilla, we find that ephaptic lateral inhibition is asymmetric such that one ORN exerts greater influence onto its neighbor. Serial block-face scanning electron microscopy of genetically identified ORNs and circuit modeling indicate that asymmetric lateral inhibition reflects a surprisingly simple mechanism: the physically larger ORN in a pair corresponds to the dominant neuron in ephaptic interactions. Thus, morphometric differences between compartmentalized ORNs account for highly specialized inhibitory interactions that govern information processing at the earliest stages of olfactory coding
Monte Carlo model of electron energy degradation in a CO2 atmosphere
A Monte Carlo model has been developed to study the degradation of <1000 eV
electrons in an atmosphere of CO2, which is one of the most abundant species in
Mars' and Venus' atmospheres. The e-CO2 cross sections are presented in an
assembled set along with their analytical representations. Monte Carlo
simulations are carried out at several energies to calculate the "yield
spectra", which embodied all the information related to electron degradation
process and can be used to calculate "yield" (or population) for any inelastic
process. The numerical yield spectra have been fitted analytically resulting in
an analytical yield spectra (AYS). We have calculated the mean energy per ion
pair and efficiencies for various inelastic processes, including the double and
dissociative double ionization of \car\ and negative ion formation. The energy
distribution of the secondary electrons produced per incident electron is also
presented at few incident energies. The mean energy per ion pair for CO2 is
37.5 (35.8) eV at 200 (1000) eV, compared to experimental value 32.7 eV at high
energies. Ionization is the dominant loss process at energies above 50 eV with
contribution of ~50%. Among the excitation processes, 13.6 eV and 12.4 eV
states are the dominant loss processes consuming ~28% energy above 200 eV.
Around and below ionization threshold, 13.6 eV, 12.4 eV, and 11.1 eV, followed
by 8.6 eV and 9.3 eV excitation states are important loss processes, while
below 10 eV vibrational excitation dominates.Comment: 31 pages, 13 figure
Differential excitation cross section measurement of O(¹D) at 20 eV electron impact
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94801/1/grl2868.pd
Img2Tab: Automatic Class Relevant Concept Discovery from StyleGAN Features for Explainable Image Classification
Traditional tabular classifiers provide explainable decision-making with
interpretable features(concepts). However, using their explainability in vision
tasks has been limited due to the pixel representation of images. In this
paper, we design Img2Tabs that classify images by concepts to harness the
explainability of tabular classifiers. Img2Tabs encode image pixels into
tabular features by StyleGAN inversion. Since not all of the resulting features
are class-relevant or interpretable due to their generative nature, we expect
Img2Tab classifiers to discover class-relevant concepts automatically from the
StyleGAN features. Thus, we propose a novel method using the Wasserstein-1
metric to quantify class-relevancy and interpretability simultaneously. Using
this method, we investigate whether important features extracted by tabular
classifiers are class-relevant concepts. Consequently, we determine the most
effective classifier for Img2Tabs in terms of discovering class-relevant
concepts automatically from StyleGAN features. In evaluations, we demonstrate
concept-based explanations through importance and visualization. Img2Tab
achieves top-1 accuracy that is on par with CNN classifiers and deep feature
learning baselines. Additionally, we show that users can easily debug Img2Tab
classifiers at the concept level to ensure unbiased and fair decision-making
without sacrificing accuracy
Multi-locus genome-wide association analysis supports the role of glutamatergic synaptic transmission in the etiology of major depressive disorder
Major depressive disorder (MDD) is a common psychiatric illness characterized by low mood and loss of interest in pleasurable activities. Despite years of effort, recent genome-wide association studies (GWAS) have identified few susceptibility variants or genes that are robustly associated with MDD. Standard single-SNP (single nucleotide polymorphism)-based GWAS analysis typically has limited power to deal with the extensive heterogeneity and substantial polygenic contribution of individually weak genetic effects underlying the pathogenesis of MDD. Here, we report an alternative, gene-set-based association analysis of MDD in an effort to identify groups of biologically related genetic variants that are involved in the same molecular function or cellular processes and exhibit a significant level of aggregated association with MDD. In particular, we used a text-mining-based data analysis to prioritize candidate gene sets implicated in MDD and conducted a multi-locus association analysis to look for enriched signals of nominally associated MDD susceptibility loci within each of the gene sets. Our primary analysis is based on the meta-analysis of three large MDD GWAS data sets (total N = 4346 cases and 4430 controls). After correction for multiple testing, we found that genes involved in glutamatergic synaptic neurotransmission were significantly associated with MDD (set-based association P = 6.9 X 10(-4)). This result is consistent with previous studies that support a role of the glutamatergic system in synaptic plasticity and MDD and support the potential utility of targeting glutamatergic neurotransmission in the treatment of MDD
Vibrational excitation cross sections of methane by electron impact
The vibrational excitation cross sections of methane (ground state) have been measured by electron impact. A crossed-beam method was used. The incident energies used were 5.0, 7.5, 10.0 and 15 eV and the angular range covered was from 24' to 156' at 12' intervals. The present results were compared with previous measurements by Tanaka et al (1983) and some considerable discrepancies were found.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48851/2/jb912414.pd
Genome-wide association for major depression through age at onset stratification
BACKGROUND: Major depressive disorder (MDD) is a disabling mood disorder, and despite a known heritable component, a large meta-analysis of genome-wide association studies revealed no replicable genetic risk variants. Given prior evidence of heterogeneity by age at onset in MDD, we tested whether genome-wide significant risk variants for MDD could be identified in cases subdivided by age at onset.
METHODS: Discovery case-control genome-wide association studies were performed where cases were stratified using increasing/decreasing age-at-onset cutoffs; significant single nucleotide polymorphisms were tested in nine independent replication samples, giving a total sample of 22,158 cases and 133,749 control subjects for subsetting. Polygenic score analysis was used to examine whether differences in shared genetic risk exists between earlier and adult-onset MDD with commonly comorbid disorders of schizophrenia, bipolar disorder, Alzheimer’s disease, and coronary artery disease.
RESULTS: We identified one replicated genome-wide significant locus associated with adult-onset (>27 years) MDD (rs7647854, odds ratio: 1.16, 95% confidence interval: 1.11–1.21, p = 5.2 × 10-11). Using polygenic score analyses, we show that earlier-onset MDD is genetically more similar to schizophrenia and bipolar disorder than adult-onset MDD.
CONCLUSIONS: We demonstrate that using additional phenotype data previously collected by genetic studies to tackle phenotypic heterogeneity in MDD can successfully lead to the discovery of genetic risk factor despite reduced sample size. Furthermore, our results suggest that the genetic susceptibility to MDD differs between adult- and earlier-onset MDD, with earlier-onset cases having a greater genetic overlap with schizophrenia and bipolar disorder
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