370 research outputs found
The relationship between species detection probability and local extinction probability.
In community-level ecological studies, generally not all species present in sampled areas are detected. Many authors have proposed the use of
estimation methods that allow detection probabilities that are <1 and that are heterogeneous among species. These methods can also be used to
estimate community-dynamic parameters such as species local extinction probability and turnover rates (Nichols et al. Ecol Appl 8:1213–1225;
Conserv Biol 12:1390–1398). Here, we present an ad hoc approach to estimating community-level vital rates in the presence of joint
heterogeneity of detection probabilities and vital rates. The method consists of partitioning the number of species into two groups using the
detection frequencies and then estimating vital rates (e.g., local extinction probabilities) for each group. Estimators from each group are combined
in a weighted estimator of vital rates that accounts for the effect of heterogeneity. Using data from the North American Breeding Bird Survey, we
computed such estimates and tested the hypothesis that detection probabilities and local extinction probabilities were negatively related. Our
analyses support the hypothesis that species detection probability covaries negatively with local probability of extinction and turnover rates. A
simulation study was conducted to assess the performance of vital parameter estimators as well as other estimators relevant to questions about
heterogeneity, such as coefficient of variation of detection probabilities and proportion of species in each group. Both the weighted estimator
suggested in this paper and the original unweighted estimator for local extinction probability performed fairly well and provided no basis for
preferring one to the other
Development of a high-resolution NGS-based HLA-typing and analysis pipeline
The human leukocyte antigen (HLA) complex contains the most polymorphic genes in the human genome. The classical HLA class I and II genes define the specificity of adaptive immune responses. Genetic variation at the HLA genes is associated with susceptibility to autoimmune and infectious diseases and plays a major role in transplantation medicine and immunology. Currently, the HLA genes are characterized using Sanger- or next-generation sequencing (NGS) of a limited amplicon repertoire or labeled oligonucleotides for allele-specific sequences. High-quality NGS-based methods are in proprietary use and not publicly available. Here, we introduce the first highly automated open-kit/open-source HLA-typing method for NGS. The method employs in-solution targeted capturing of the classical class I (HLA-A, HLA-B, HLA-C) and class II HLA genes (HLA-DRB1, HLA-DQA1, HLA-DQB1, HLA-DPA1, HLA-DPB1). The calling algorithm allows for highly confident allele-calling to three-field resolution (cDNA nucleotide variants). The method was validated on 357 commercially available DNA samples with known HLA alleles obtained by classical typing. Our results showed on average an accurate allele call rate of 0.99 in a fully automated manner, identifying also errors in the reference data. Finally, our method provides the flexibility to add further enrichment target regions
Spin-dependent cross sections from the three-body photodisintegration of He 3 at incident energies of 12.8 and 14.7 MeV
The first measurement of the three-body photodisintegration of polarized 3He using a circularly polarized photon beam has been performed at incident energies of 12.8 and 14.7 MeV. This measurement was carried out at the high-intensity γ-ray source located at Triangle Universities Nuclear Laboratory. A high-pressure 3He target, polarized via spin exchange optical pumping with alkali metals, was used in the experiment. The spin-dependent double- and single-differential cross sections from 3He(γ,n)pp for laboratory angles varying from 30° to 165° are presented and compared with state-of-the-art three-body calculations. The data reveal the importance of including the Coulomb interaction between protons in the three-body calculations
DETERMINAÇÃO DA CONDUTIVIDADE HIDRÁULICA E DA SORVIDADE DE UM SOLO NÃO-SATURADO UTILIZANDO-SE PERMEÂMETRO A DISCO
Using microphone arrays to investigate microhabitat selection by declining breeding birds
Understanding the microhabitat preferences of animals can help managers to develop better conservation and recovery strategies but this is challenging. Traditional methods are limited by cost, accuracy and human resources. In this study, we investigated avian microhabitat preferences using microphone arrays that are capable of accurately locating vocalizing birds. Our objective was to identify the microhabitat associations of two common species in steep population decline, the Boreal Chickadee Poecile hudsonicus and the Cape May Warbler Setophaga tigrina. We deployed 68 eight‐channel arrays at random locations in Labrador, Canada, during the 2016 avian breeding season. We returned in 2017 to the 18 array locations where the target species had been detected the previous year and characterized the microhabitat at the exact locations where they had been detected. We also characterized the microhabitat at randomly determined control locations. Results show that Boreal Chickadees select trees with greater diameter‐at‐breast‐height that are surrounded by greater stem density. We did not find evidence that Cape May Warblers exhibit microhabitat selection during song production. The study shows that microphone arrays are an effective tool for identifying preferred microhabitat that could be incorporated into future conservation or recovery strategies
Quorum sensing:Implications on rhamnolipid biosurfactant production
Quorum sensing (QS) has received significant attention in the past few decades. QS describes population density dependent cell to cell communication in bacteria using diffusible signal molecules. These signal molecules produced by bacterial cells, regulate various physiological processes important for social behavior and pathogenesis. One such process regulated by quorum sensing molecules is the production of a biosurfactant, rhamnolipid. Rhamnolipids are important microbially derived surface active agents produced by Pseudomonas spp. under the control of two interrelated quorum sensing systems; namely las and rhl. Rhamnolipids possess antibacterial, antifungal and antiviral properties. They are important in motility, cell to cell interactions, cellular differentiation and formation of water channels that Currently, biosurfactants are unable to compete economically with chemically synthesized compounds in the market due to high production costs. Once the genes required for biosurfactant production have been identified, they can be placed under the regulation of strong promoters in nonpathogenic, heterologous hosts to enhance production. The production of rhamnolipids could be increased by cloning both the rhlAB rhamnosyltransferase genes and the rhlRI quorum sensing system into a suitable bacterium such as E. coli or P. putida and facilitate rhamnolipid production. Biosurfactants can also be genetically engineered for different industrial applications assuming there is a strong understanding of both the genetics and the structure-function relationships of each component of the molecule. Genetic engineering of surfactin has already been reported, with recent papers describing the creation of novel peptide structures from the genetic recombination of several peptide synthetases. Recent application of dynamic metabolic engineering strategies for controlled gene expression could lower the cost of fermentation processes by increasing the product formation. Therefore, by integrating a genetic circuit into applications of metabolic engineering the biochemical production can be optimized. Furthermore, novel strategies could be designed on the basis of information obtained from the studies of quorum sensing and biosurfactants produced suggesting enormous practical applications.</p
Two truncating variants in FANCC and breast cancer risk
Fanconi anemia (FA) is a genetically heterogeneous disorder with 22 disease-causing genes reported to date. In some FA genes, monoallelic mutations have been found to be associated with breast cancer risk, while the risk associations of others remain unknown. The gene for FA type C, FANCC, has been proposed as a breast cancer susceptibility gene based on epidemiological and sequencing studies. We used the Oncoarray project to genotype two truncating FANCC variants (p.R185X and p.R548X) in 64,760 breast cancer cases and 49,793 controls of European descent. FANCC mutations were observed in 25 cases (14 with p.R185X, 11 with p.R548X) and 26 controls (18 with p.R185X, 8 with p.R548X). There was no evidence of an association with the risk of breast cancer, neither overall (odds ratio 0.77, 95% CI 0.44-1.33, p = 0.4) nor by histology, hormone receptor status, age or family history. We conclude that the breast cancer risk association of these two FANCC variants, if any, is much smaller than for BRCA1, BRCA2 or PALB2 mutations. If this applies to all truncating variants in FANCC it would suggest there are differences between FA genes in their roles on breast cancer risk and demonstrates the merit of large consortia for clarifying risk associations of rare variants
Serologic Reactivity Reflects Clinical Expression of Ulcerative Colitis in Children
Background In contrast to pediatric Crohn's disease (CD), little is known in pediatric ulcerative colitis (UC) about the relationship between disease phenotype and serologic reactivity to microbial and other antigens. Aim The aim of this study was to examine disease phenotype and serology in a well-characterized inception cohort of children newly diagnosed with UC during the PROTECT Study (Predicting Response to Standardized Pediatric Colitis Therapy). Methods Patients were recruited from 29 participating centers. Demographic, clinical, laboratory, and serologic (pANCA, ASCA IgA/IgG, Anti-CBir1, and Anti-OmpC) data were obtained from children 4-17 years old with UC. Results Sixty-five percent of the patients had positive serology for pANCA, with 62% less than 12 years old and 66% 12 years old or older. Perinuclear anti-neutrophil cytoplasmic antibodies did not correspond to a specific phenotype though pANCA ò100, found in 19%, was strongly associated with pancolitis (P = 0.003). Anti-CBir1 was positive in 19% and more common in younger children with 32% less than 12 years old as compared with 14% 12 years old or older (P < 0.001). No association was found in any age group between pANCA and Anti-CBir1. Relative rectal sparing was more common in +CBir1, 16% versus 7% (P = 0.02). Calprotectin was lower in Anti-CBir1+ (Median [IQR] 1495 mcg/g [973-3333] vs 2648 mcg/g [1343-4038]; P = 0.04). Vitamin D 25-OH sufficiency was associated with Anti-CBir1+ (P = 0.0009). Conclusions The frequency of pANCA in children was consistent with adult observations. High titer pANCA was associated with more extensive disease, supporting the idea that the magnitude of immune reactivity may reflect disease severity. Anti-CBir1+ was more common in younger ages, suggesting host-microbial interactions may differ by patient age
Anticorpos policlonais em dietas com alta inclusão de concentrado para bovinos confinados
Among alternatives to replace ionophores, which are classified as antibiotics by some committees, the feeding of polyclonal antibodies have shown an interesting and economically efficient alternative. Recent studies have demonstrated some advantages of adding polyclonal antibodies into high-concentrate diets for feedlot cattle, showed by increased performance and ruminal health, in some cases similar to sodium monensin. However, there are blind spots of this innovated technology that still need to be elucidated, as example, if the dry form of the preparation is inactivated and decreased carcass-dressing percentage. All in all, this review demonstrates the possibility of replacing sodium monensin by this feed additive without negatively impacting animal performance and profit of cattle feeders in Brazil.Dentre as alternativas para substituir o uso de ionóforos classificados como antibiótico por alguns comitês, a utilização de anticorpos policlonais classificados como promotores de crescimento naturais tem se mostrado alternativa interessante e economicamente eficiente. Recentes estudos demonstraram pontos positivos na utilização desse aditivo em dietas com alta inclusão de ingredientes concentrados para bovinos confinados, traduzido por melhora de desempenho e saúde ruminal, em alguns casos, semelhantes à monensina sódica. No entanto, alguns pontos dessa nova tecnologia ainda devem ser elucidados, entre eles, a possível perda de atividade da forma sólida de apresentação do preparado e a diminuição do rendimento de carcaça encontrado em alguns estudos. Contudo, a presente revisão destaca a possibilidade de substituição da monensina sódica por anticorpos policlonais sem resultar em diminuição de desempenho e de rentabilidade para a bovinocultura de corte brasileira.Universidade Estadual Paulista (UNESP) Curso de ZootecniaUNESP Faculdade de Medicina Veterinária e Zootecnia (FMVZ) Departamento de Melhoramento e Nutrição AnimalUNESP FMVZ Departamento de Produção AnimalUniversidade Estadual Paulista (UNESP) Curso de ZootecniaUNESP Faculdade de Medicina Veterinária e Zootecnia (FMVZ) Departamento de Melhoramento e Nutrição AnimalUNESP FMVZ Departamento de Produção Anima
Measurement of the total cross section and ρ -parameter from elastic scattering in pp collisions at √s=13 TeV with the ATLAS detector
In a special run of the LHC with β⋆=2.5 km, proton–proton elastic-scattering events were recorded at s√=13 TeV with an integrated luminosity of 340 μb−1 using the ALFA subdetector of ATLAS in 2016. The elastic cross section was measured differentially in the Mandelstam t variable in the range from −t=2.5⋅10−4 GeV2 to −t=0.46 GeV2 using 6.9 million elastic-scattering candidates. This paper presents measurements of the total cross section σtot, parameters of the nuclear slope, and the ρ-parameter defined as the ratio of the real part to the imaginary part of the elastic-scattering amplitude in the limit t→0. These parameters are determined from a fit to the differential elastic cross section using the optical theorem and different parameterizations of the t-dependence. The results for σtot and ρ are σtot(pp→X)=104.7±1.1 mb ,ρ=0.098±0.011. The uncertainty in σtot is dominated by the luminosity measurement, and in ρ by imperfect knowledge of the detector alignment and by modelling of the nuclear amplitude.publishedVersio
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