5,749 research outputs found
Description of a subset of single events from the BATSE gamma ray burst data
About 15 percent of the gamma ray bursts in the Burst and Transient Source Experiment (BATSE) data exhibit a simple light curve consisting mainly of a single pulse without fine substructures. In 12 of the burst profiles, the pulse shapes show a linear rise and decay. Three events have a distinct sharp rise followed by a long, almost exponential decay. Searches based on only a sharp rise selection criterion resulted in five more grbs with different profile complexities. In one case, we identify an envelope of fast oscillations with a long, softer tail lasting about 100 seconds. The majority of events were detectable at energies above 300 keV, with tentative estimates for fluences that vary between 4.0 x 10(exp -8) and 5.4 x 10(exp -6) ergs/sq cm. We describe here their general characteristics (durations, rise-decay times) and their hardness ratios
Monitoring Cen X-3 with BATSE
The eight uncollimated BATSE Large Area Detectors (LAD's) provide the ability to monitor pulsed hard x ray sources on a nearly continuous basis. Using data from the LAD's, the pulse timing and pulsed flux of the 4.8 second period binary x ray pulsar Centaurus X-3 was analyzed over a two month period. The methods and initial results of this analysis, which includes both data folded onboard GRO and 1.024 second resolution discriminator rates folded on the ground, are presented
Questioning the Quality of 16S rRNA Gene Sequences Derived From Human Gut Metagenome-Assembled Genomes
The recent introduction of metagenome-assembled genomes (MAGs) has marked a major milestone in the human gut microbiome field (Almeida et al., 2019; Nayfach et al., 2019; Pasolli et al., 2019). Such reference-free, de novo-assembled genomes (Hugerth et al., 2015) have revealed a wide range of hitherto uncultured microbial species in human gut samples. The significance of MAGs in unravelling human gut microbial diversity was supported by their overwhelming representation in a comprehensive human gut prokaryotic collection filtered by metagenome data dereplicated at 97.5% average nucleotide identity (ANI) (Hiseni et al., 2021). More than 90% of the collection consists of MAGs, while the rest of the collection mainly comprises RefSeq genomes (Figure 1A).publishedVersio
HumGut: a comprehensive human gut prokaryotic genomes collection filtered by metagenome data
Background
A major bottleneck in the use of metagenome sequencing for human gut microbiome studies has been the lack of a comprehensive genome collection to be used as a reference database. Several recent efforts have been made to re-construct genomes from human gut metagenome data, resulting in a huge increase in the number of relevant genomes. In this work, we aimed to create a collection of the most prevalent healthy human gut prokaryotic genomes, to be used as a reference database, including both MAGs from the human gut and ordinary RefSeq genomes.
Results
We screened > 5,700 healthy human gut metagenomes for the containment of > 490,000 publicly available prokaryotic genomes sourced from RefSeq and the recently announced UHGG collection. This resulted in a pool of > 381,000 genomes that were subsequently scored and ranked based on their prevalence in the healthy human metagenomes. The genomes were then clustered at a 97.5% sequence identity resolution, and cluster representatives (30,691 in total) were retained to comprise the HumGut collection. Using the Kraken2 software for classification, we find superior performance in the assignment of metagenomic reads, classifying on average 94.5% of the reads in a metagenome, as opposed to 86% with UHGG and 44% when using standard Kraken2 database. A coarser HumGut collection, consisting of genomes dereplicated at 95% sequence identity—similar to UHGG, classified 88.25% of the reads. HumGut, half the size of standard Kraken2 database and directly comparable to the UHGG size, outperforms them both.
Conclusions
The HumGut collection contains > 30,000 genomes clustered at a 97.5% sequence identity resolution and ranked by human gut prevalence. We demonstrate how metagenomes from IBD-patients map equally well to this collection, indicating this reference is relevant also for studies well outside the metagenome reference set used to obtain HumGut. All data and metadata, as well as helpful code, are available at http://arken.nmbu.no/~larssn/humgut/.publishedVersio
Detecting integration of top-down information using the mismatch negativity: Preliminary evidence from phoneme restoration
The current study utilizes mismatch negativity in the phenomenon of phoneme restoration to investigate the critical debate regarding the integration of top down (lexical) and bottom up (acoustic) processing in spoken word recognition. Phoneme restoration, which occurs when phonemes missing from a speech signal are restored by the brain and may appear to be heard, was examined in a multi-standard oddball paradigm. Participants heard stimuli while watching a quiet animated film. Stimuli were divided into word and non- word conditions, with noise added to some stimuli to make them ambiguous. The many-to-one ratio of standards to deviants for generation of mismatch negativity (MMN) was achieved only if the brain could recover the missing phoneme in the ambiguous, noise-spliced stimuli. Both word and nonword conditions were compared to verify that an elicited MMN among words was contingent on involvement of the lexicon in the grouping of standards, and not some more general cognitive grouping procedure. Results from seven participants show preliminary support for the predicted effect: i.e., mismatch negativity for words but not for nonwords. This effect is contingent on phoneme restoration, and thus is consistent with recent literature suggesting that MMN is sensitive to higher information structures such as the mental lexicon.
Keywords: phoneme restoration, MMN, lexical access, top-down informatio
Detecting integration of top-down information using the mismatch negativity: Preliminary evidence from phoneme restoration
The current study utilizes mismatch negativity in the phenomenon of phoneme restoration to investigate the critical debate regarding the integration of top down (lexical) and bottom up (acoustic) processing in spoken word recognition. Phoneme restoration, which occurs when phonemes missing from a speech signal are restored by the brain and may appear to be heard, was examined in a multi-standard oddball paradigm. Participants heard stimuli while watching a quiet animated film. Stimuli were divided into word and non- word conditions, with noise added to some stimuli to make them ambiguous. The many-to-one ratio of standards to deviants for generation of mismatch negativity (MMN) was achieved only if the brain could recover the missing phoneme in the ambiguous, noise-spliced stimuli. Both word and nonword conditions were compared to verify that an elicited MMN among words was contingent on involvement of the lexicon in the grouping of standards, and not some more general cognitive grouping procedure. Results from seven participants show preliminary support for the predicted effect: i.e., mismatch negativity for words but not for nonwords. This effect is contingent on phoneme restoration, and thus is consistent with recent literature suggesting that MMN is sensitive to higher information structures such as the mental lexicon. Keywords: phoneme restoration, MMN, lexical access, top-down information
Rating the Financial Health of U.S. Production Agriculture using Synthetic Credit Rating
Agribusiness, Agricultural and Food Policy, Production Economics,
Liquid array diagnostics: A novel method for rapid detection of microbial communities in single-tube multiplex reactions
publishedVersio
Electron Beam Induced Luminescence of SiO2 Optical Coatings
Optical coatings of disordered thin film SiO2/SiOx dielectric samples on reflective metal substrates exhibited cathodoluminescence under electron beam irradiation. Measurements of the absolute radiance and emission spectra as functions of incident electron energy, flux and power over a range of sample temperatures are reported. Radiance reached a saturation plateau at high incident electron power. Well below saturation radiance scaled with deposited power, that is linearly with incident power for lower-energy non-penetrating electrons and decreasing with increasing energy for penetrating radiation. Four bands were observed in spectral measurements from 300 nm to 1000 nm. Changes in peak intensity and shifts in peak energies as functions of temperature are described. The observations are explained in terms of a simple disordered band theory model and the transitions that take place between electrons in extended conduction states and localized trapped states associated with structural or compositional defects in the highly disordered insulating materials; this provides a fundamental basis for understanding the dependence of cathodoluminescence on irradiation time, incident flux and energy, and sample thickness and temperature
Police stress and teacher stress at work and at home
This study compared police officers and teachers in three communities--which varied in size, geographical location, and economic base--for differences in perceived occupational stress and for differences in the patterns of perceived job stress, perceived nonjob stress, and both perceived job and life stressors. For police officers, higher levels of job stress were associated with higher levels on measures of perceived job stressors. This relationship varied from city to city, with the relationship holding for the city in which both police operations and school operations were relatively normal, with no difference between police and teachers in the city in which the school administration was in conflict with its employees, and with a reversal in the city in which the police administration was noted for its excellent management skills.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29609/1/0000698.pd
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