3,819 research outputs found
Biological Species Concepts in Eastern North American Populations of Lentinellus ursinus
As part of a biosystematic study of the Lentinellus ursinus species complex, field and herbarium specimens from North America, Central America, and Europe were examined. Single basidiospore isolates from basidiomata collected in Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Tennessee, North Carolina, Wisconsin, Costa Rica, and Austria were crossed in all possible combinations to determine the mating system operating in each population. All populations exhibited bifactorial or tetrapolar mating systems. Tester strains were then crossed to identify intercompatible populations and to determine if morphological species in the L. ursinus species complex are congruent with biological species. Three biological species were recognized and identified as L. ursinus, L. angustifolius, and L. vulpinus. Polyspore isolates were subsequently used in culture mat and phenoloxidase analyses to facilitate identification of somatic cultures. The production of gloeocystidia and/or chlamydospores is taxonomically important for identifying somatic cultures of these species. All three taxa produced laccase, tyrosinase, and peroxidase in culture and were identified as white-rot fungi. This represents the first confirmed report of L. angustifolius from North America
A short note on the presence of spurious states in finite basis approximations
The genesis of spurious solutions in finite basis approximations to operators
which possess a continuum and a point spectrum is discussed and a simple
solution for identifying these solutions is suggested
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Genome-Wide Association Study and Subsequent Exclusion of ATCAY as a Candidate Gene Involved in Equine Neuroaxonal Dystrophy Using Two Animal Models.
Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is an inherited neurodegenerative disorder of unknown etiology. Clinical signs of neurological deficits develop within the first year of life in vitamin E (vitE) deficient horses. A genome-wide association study (GWAS) was carried out using 670,000 SNP markers in 27 case and 42 control Quarter Horses. Two markers, encompassing a 2.5 Mb region on ECA7, were associated with the phenotype (p = 2.05 × 10-7 and 4.72 × 10-6). Within this region, caytaxin (ATCAY) was identified as a candidate gene due to its known role in Cayman Ataxia and ataxic/dystonic phenotypes in mouse models. Whole-genome sequence data in four eNAD/EDM and five unaffected horses identified 199 associated variants within the ECA7 region. MassARRAY® genotyping was performed on these variants within the GWAS population. The three variants within ATCAY were not concordant with the disease phenotype. No difference in expression or alternative splicing was identified using qRT-PCR in brainstem across the ATCAY transcript. Atcayji-hes mice were then used to conduct functional analysis in a second animal model. Histologic lesions were not identified in the central nervous system of Atcayji-hes mice. Additionally, supplementation of homozygous Atcayji-hes mice with 600 IU/day of dl-α-tocopheryl acetate (vitE) during gestation, lactation, and adulthood did not improve the phenotype. ATCAY has therefore been excluded as a candidate gene for eNAD/EDM
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Data Assimilation in Models with Convective Adjustment
Practical hydrostatic ocean models are often restricted to statically stable configurations by the use of a convective adjustment. A common way to do this is to assign an infinite boat conductivity to the water at a given level if the water column should become statically unstable. This is implemented in the form of a switch. When a statically unstable configuration is detected, it is immediately replaced with a statically stable one in which heat is conserved. In this approach, the model is no longer governed by a smooth set of equations, and usual techniques of variational data assimilation must be modified. In this note, a simple one-dimensional diffusive model is presented. Despite its simplicity, this model captures the essential behavior of the convective adjustment scheme in a widely used ocean general circulation model. Since this simple model can be derived from the more complex general circulation model, it then follows that many of the properties of the constrained system can be observed in this very simple scalar ordinary differential equation with a constraint on the solution. Techniques from the theory of optimal control are used to find solutions of a simple formulation of the variational data assimilation problem in this simple case. The optimal solution involves the solution of a nonlinear problem, even when the unconstrained dynamics are linear. In cases with discontinuous dynamics, one cannot define the adjoint of the linearized system in a straightforward manner. The very simplest variational formulation is shown to have nonunique stationary points and undesirable physical consequences. Modifications that lead to better behaved calculations and more meaningful solutions are presented. Whereas it is likely that the underlying principles from control theory are applicable to practical ocean models, the technique used to solve the simple problem may be applicable only to steady problems. Derivation of suitable techniques for initial value problems will involve a major research effort
New species of Capronia (Herpotrichiellaceae, Ascomycota) from Patagonian forests, Argentina
Three new species belonging to Capronia are described from plants native to the Andean Patagonian forests, Argentina. The first record of C. chlorospora in South America is also reported. The identity of the three new species is based on detailed morpho-anatomical observations as well as analyses of ITS and LSU nuclear rDNA. A key to the Capronia species present in Argentina is provided.Fil: Sanchez, Romina Magali. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Miller Andrew, N.. University of Illinois at Urbana; Estados UnidosFil: Bianchinotti, Maria Virginia. Universidad Nacional del Sur. Departamento de BiologĂa, BioquĂmica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentin
Elastic constants of 3-, 4- and 6-connected chiral and anti-chiral honeycombs subject to uniaxial in-plane loading
Finite Element models are developed for the in-plane linear elastic constants of a family of honeycombs comprising arrays of cylinders connected by ligaments. Honeycombs having cylinders with 3, 4 and 6 ligaments attached to them are considered, with two possible configurations explored for each of the 3- (trichiral and anti-trichiral) and 4- (tetrachiral and anti-tetrachiral) connected systems. Honeycombs for each configuration have been manufactured using rapid prototyping and subsequently characterised for mechanical properties through in-plane uniaxial loading to verify the models. An interesting consequence of the family of 'chiral' honeycombs presented here is the ability to produce negative Poisson's ratio (auxetic) response. The deformation mechanisms responsible for auxetic functionality in such honeycombs are discussed
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Lipid peroxidation biomarkers for evaluating oxidative stress in equine neuroaxonal dystrophy.
BackgroundEquine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is a neurodegenerative disorder affecting genetically predisposed foals maintained on an α-tocopherol (α-TOH) deficient diet. Currently no antemortem diagnostic test for eNAD/EDM is available.HypothesisBecause α-TOH deficiency is associated with increased lipid peroxidation, it was hypothesized that F2 -isoprostanes (F2 IsoP), F4 -neuroprostanes (F4 NP) and oxysterols derived from free radical oxidation would be increased in the cerebrospinal fluid (CSF) and neural tissue of eNAD/EDM affected horses and could serve as potential biomarkers for disease.AnimalsIsoprostane Study A: 14 Quarter horse foals (10 healthy foals and 4 eNAD/EDM affected foals) at 1 and 6 months of age. Isoprostane Study B: 17 eNAD/EDM affected and 10 unaffected horses ≥ 1-4 years of age. Oxysterol study: eNAD/EDM affected (n = 14, serum; n = 11, CSF; n = 10, spinal cord [SC]) and unaffected horses 1-4 years of age (n = 12, serum; n = 10, CSF; n = 7, SC).ProceduresCerebrospinal fluid [F2 IsoP] and [F4 NP] were assessed using gas chromatography-negative ion chemical ionization mass spectrometry. Serum, CSF, and cervical SC [oxysterols] were quantified using high performance liquid chromatography mass spectrometry. Results were compared with respective α-TOH concentrations.ResultsSpinal cord [7-ketocholesterol], [7-hydroxycholesterol], and [7-keto-27-hydrocholesterol] were higher in eNAD/EDM horses whereas [24-ketocholesterol] was lower. No significant difference was found in CSF [F2 IsoP] and [F4 NP], serum [oxysterols] and CSF [oxysterols] between eNAD/EDM affected and unaffected horses. No correlation was found between [F2 IsoP], [F4 NP], or [oxysterols] and respective [α-TOH].Conclusions and clinical importanceIn the SC, targeted markers of cholesterol oxidation were significantly increased in horses with eNAD/EDM
Effect of bromoform and linseed oil on greenhouse gas emissions from stored beef manure
Emissions of carbon dioxide, methane, and nitrous oxide – potent greenhouse gases - from stored beef feedlot manure are a significant concern relative to climate change. Research on methane reduction strategies for enteric emissions has identified the application of organic additives, such as bromoform and linseed oil, to ruminant diets as potential solutions for reducing enteric emissions and pathogenic bacteria in excreted manure. The objective of this study was to determine the effect of bromoform and linseed oil on greenhouse gas emissions from beef feedlot manure, and on E. coli concentration in beef cattle manure, during a 5-week storage period. The experiment used a completely randomized block design (CRBD) with 4 replications of 5 treatments: 5.5 g/kg and 11 g/kg of linseed oil, 4.3 g/kg, and 8.6 g/kg of bromoform, and a control receiving no additives. Treatments were added to a 3-liter mix of 50% manure, 50% soil, mixed by hand, and stored in airtight columns (10-cm diameter x 40-cm tall) in a greenhouse maintained at 25 C during the storage period. Gas samples were collected 10 times during the 5-week test period using a 15 ml syringe and were analyzed using gas chromatography to determine concentrations of methane, carbon dioxide and nitrous oxide. A 1-cm diameter core of material was removed from the top 20 cm of each column 4 times during the sampling period to conduct bacterial enumerations. Quantification of E.coli in samples was determined by incubating serial dilutions for 24 hours at 36 C and manually counting colonies. Preliminary results of the study showed that through 5 weeks of observation, 11g/kg linseed oil reduced the average concentration of E. coli (p \u3c0.05) compared to all other treatments. Preliminary results also indicate that bromoform at 8.6g/kg decreased carbon dioxide emissions but neither bromoform concentration had any significant effect on methane or nitrous oxide emissions compared to control. Linseed oil at 11g/kg increased methane emissions compared to control but neither linseed oil concentrations significantly impacted the average flux of carbon dioxide, or nitrous oxide from manure storages when compared to control
Bimodal release ondansetron for acute gastroenteritis among adolescents and adults: A randomized clinical trial
Importance: Vomiting resulting from acute gastroenteritis is commonly treated with intravenous antiemetics in acute care settings. If oral treatment were beneficial, patients might not need intravenous administered hydration or medication. Furthermore, a long-acting treatment could provide sustained relief from nausea and vomiting.
Objective: To determine whether an experimental long-acting bimodal release ondansetron tablet decreases gastroenteritis-related vomiting and eliminates the need for intravenous therapy for 24 hours after administration.
Design, Setting, and Participants: This placebo-controlled, double-blind, randomized clinical trial included patients from 19 emergency departments and 2 urgent care centers in the United States from December 8, 2014, to February 17, 2017. Patients 12 years and older with at least 2 vomiting episodes from presumed gastroenteritis in the previous 4 hours and symptoms with less than 36 hours\u27 duration were randomized using a 3:2 active to placebo ratio. Analyses were performed on an intent-to-treat basis and conducted from June 1, 2017, to November 1, 2017.
Intervention: Bimodal release ondansetron tablet containing 6 mg of immediate release ondansetron and 18 mg of a 24-hour release matrix for a total of 24 mg of ondansetron.
Main Outcomes and Measures: Treatment success was defined as no further vomiting, no need for rescue medication, and no intravenous hydration for 24 hours after bimodal release ondansetron administration.
Results: Analysis included 321 patients (mean [SD] age, 29.0 [11.1] years; 195 [60.7%] women), with 192 patients in the bimodal release ondansetron group and 129 patients in the placebo group. Treatment successes were observed in 126 patients in the bimodal release ondansetron group (65.6%) compared with 70 patients in the placebo group (54.3%), with an 11.4% (95% CI, 0.3%-22.4%) absolute probability difference. The proportion of treatment success was 21% higher among patients who received bimodal release ondansetron compared with those who received a placebo (relative risk, 1.21; 95% CI, 1.00-1.46; P = .04). In an analysis including only patients with a discharge diagnosis of acute gastroenteritis and no major protocol violations, there were 123 treatment successes (69.5%) in the bimodal release ondansetron group compared with 67 treatment successes (54.9%) in the placebo group (relative risk, 1.27; 95% CI, 1.05-1.53; P = .01). Adverse effects were infrequent and similar to the known safety profile of ondansetron.
Conclusions and Relevance: This randomized clinical trial found that a long-acting bimodal release oral ondansetron tablet was an effective antiemetic among adolescents and adults with moderate to severe vomiting from acute gastroenteritis. The drug benefits extended to 24 hours after administration. Bimodal release ondansetron may decrease the need for intravenous access and emergency department care to manage acute gastroenteritis.
Trial Registration: ClinicalTrials.gov identifier: NCT02246439
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Comparative genomics and phylogenomic investigation of the class Geoglossomycetes provide insights into ecological specialization and the systematics of Pezizomycotina
Despite their global presence and ubiquity, members of the class Geoglossomycetes (Pezizomycotina, Ascomycota) are understudied systematically and ecologically. These fungi have long been presumed saprobic due to their occurrence in or near leaf litter and soils. Additionally, they lack an apparent association with other organisms, reinforcing this perception. However, observations of sporocarps near ericaceous shrubs have given rise to an alternative hypothesis that members of Geoglossomycetes may form ericoid mycorrhizae or ectomycorrhizae. This claim, however, has yet to be confirmed via microscopy or amplicon-based studies examining root communities. As a result, our current understanding of their ecology is based on cursory observations. This study presents a comparative analysis of genomic signatures related to ecological niche to investigate the hypothesis of an ericoid mycorrhizal or ectomycorrhizal ecology in the class. We compared the carbohydrate-active enzyme (CAZyme) and secondary metabolite contents of six newly sequenced Geoglossomycetes genomes with those of fungi representing specific ecologies across Pezizomycotina. Our analysis reveals CAZyme and secondary metabolite content patterns consistent with ectomycorrhizal (EcM) members of Pezizomycotina. Specifically, we found a reduction in CAZyme-encoding genes and secondary metabolite clusters that suggests a mutualistic ecology. Our work includes the broadest taxon sampling for a phylogenomic study of Pezizomycotina to date. It represents the first functional genomic and genome-scale phylogenetic study of the class Geoglossomycetes and improves the foundational knowledge of the ecology and evolution of these understudied fungi
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