885 research outputs found
Methods for Capturing, Marking, and Estimating Survival of Northern Bobwhite Chicks (Poster Abstract)
Lack of techniques to capture, mark, and observe chicks from hatch to fall has hindered our ability to understand this critical life stage of northern bobwhite (Colinus virginianus) and other galliforms. We present 2 methods for capturing wild, free-ranging northern bobwhite chicks associated with a radiomarked adult and demonstrate application of capture-recapture estimators. Both capture techniques involve monitoring radiomarked adults, locating nests, determining date of hatch, and then locating roosting adults with broods prior to sunrise during the pre-flight period (1â12 days post-hatch). The first technique involves erecting a temporary circular fence around the roosting radio-marked bird and brood, securing the edges with dirt, and systematically clearing all vegetation and ground debris until chicks are captured. The second technique involves placing a temporary fence in a ââVââ formation with a small mesh funnel trap placed at the apex. Birds are then ââcorralledââ into the funnel trap. We used both methods during the breeding seasons of 1997â99. Overall, we captured 762 chicks from 137 broods. Of 131 capture attempts using the ring method, 18.3% (n = 24) were complete failures, 13.7% (n = 18) resulted in partial capture, whereas 68% (n = 89) resulted in complete capture. Using the funnel method, 22.2% (n = 2) of attempts were complete failures, 22.2% (n = 2) resulted in partial captures, and 55.6% (n = 5) resulted in complete brood capture. Captured chicks can be permanently and uniquely marked using monel patagial wing bands. We demonstrate application of capture-recapture models in program MARK to estimate chick survival from hatch to recruitment in the fall population (Oct 1)
Massive Electrodynamics and Magnetic Monopoles
Including torsion in the geometric framework of the Weyl-Dirac theory we
build up an action integral, and obtain from it a gauge covariant (in the Weyl
sense) general relativistic massive electrodynamics. Photons having an
arbitrary mass, electric, and magnetic currents (Dirac's monopole) coexist
within this theory. Assuming that the space-time is torsionless, taking the
photons mass zero, and turning to the Einstein gauge we obtain Maxwell's
electrodynamics.Comment: LaTex File, 9 pages, no figure
Simulating gas giant exoplanet atmospheres with Exo-FMS: Comparing semi-grey, picket fence and correlated-k radiative-transfer schemes
Radiative-transfer (RT) is a fundamental part of modelling exoplanet
atmospheres with general circulation models (GCMs). An accurate RT scheme is
required for estimates of the atmospheric energy transport and for gaining
physical insight from model spectra. We implement three RT schemes for Exo-FMS:
semi-grey, non-grey `picket fence', and real gas with correlated-k. We
benchmark the Exo-FMS GCM using these RT schemes to hot Jupiter simulation
results from the literature. We perform a HD 209458b-like simulation with the
three schemes and compare their results. These simulations are then
post-processed to compare their observable differences. The semi-grey scheme
results show qualitative agreement with previous studies in line with
variations seen between GCM models. The real gas model reproduces well the
temperature and dynamical structures from other studies. After post-processing
our non-grey picket fence scheme compares very favourably with the real gas
model, producing similar transmission spectra, emission spectra and phase curve
behaviours. Exo-FMS is able to reliably reproduce the essential features of
contemporary GCM models in the hot gas giant regime. Our results suggest the
picket fence approach offers a simple way to improve upon RT realism beyond
semi-grey schemes.Comment: MNRAS accepted 22 June 2021 - V2, typos fixe
TIGIT Marks Exhausted T Cells, Correlates with Disease Progression, and Serves as a Target for Immune Restoration in HIV and SIV Infection.
HIV infection induces phenotypic and functional changes to CD8+ T cells defined by the coordinated upregulation of a series of negative checkpoint receptors that eventually result in T cell exhaustion and failure to control viral replication. We report that effector CD8+ T cells during HIV infection in blood and SIV infection in lymphoid tissue exhibit higher levels of the negative checkpoint receptor TIGIT. Increased frequencies of TIGIT+ and TIGIT+ PD-1+ CD8+ T cells correlated with parameters of HIV and SIV disease progression. TIGIT remained elevated despite viral suppression in those with either pharmacological antiretroviral control or immunologically in elite controllers. HIV and SIV-specific CD8+ T cells were dysfunctional and expressed high levels of TIGIT and PD-1. Ex-vivo single or combinational antibody blockade of TIGIT and/or PD-L1 restored viral-specific CD8+ T cell effector responses. The frequency of TIGIT+ CD4+ T cells correlated with the CD4+ T cell total HIV DNA. These findings identify TIGIT as a novel marker of dysfunctional HIV-specific T cells and suggest TIGIT along with other checkpoint receptors may be novel curative HIV targets to reverse T cell exhaustion
Insulin pump therapy with automated insulin suspension in response to hypoglycemia: reduction in nocturnal hypoglycemia in those at greatest risk.
OBJECTIVE: To evaluate a sensor-augmented insulin pump with a low glucose suspend (LGS) feature that automatically suspends basal insulin delivery for up to 2 h in response to sensor-detected hypoglycemia. RESEARCH DESIGN AND METHODS: The LGS feature of the Paradigm Veo insulin pump (Medtronic, Inc., Northridge, CA) was tested for 3 weeks in 31 adults with type 1 diabetes. RESULTS: There were 166 episodes of LGS: 66% of daytime LGS episodes were terminated within 10 min, and 20 episodes lasted the maximum 2 h. LGS use was associated with reduced nocturnal duration â€2.2 mmol/L in those in the highest quartile of nocturnal hypoglycemia at baseline (median 46.2 vs. 1.8 min/day, P = 0.02 [LGS-OFF vs. LGS-ON]). Median sensor glucose was 3.9 mmol/L after 2-h LGS and 8.2 mmol/L at 2 h after basal restart. CONCLUSIONS: Use of an insulin pump with LGS was associated with reduced nocturnal hypoglycemia in those at greatest risk and was well accepted by patients
The complete genome sequence of the phytopathogenic fungus Sclerotinia sclerotiorum reveals insights into the genome architecture of broad host range pathogens
Sclerotinia sclerotiorum is a phytopathogenic fungus with over 400 hosts including numerous economically important cultivated species. This contrasts many economically destructive pathogens that only exhibit a single or very few hosts. Many plant pathogens exhibit a âtwo-speedâ genome. So described because their genomes contain alternating gene rich, repeat sparse and gene poor, repeat-rich regions. In fungi, the repeat-rich regions may be subjected to a process termed repeat-induced point mutation (RIP). Both repeat activity and RIP are thought to play a significant role in evolution of secreted virulence proteins, termed effectors. We present a complete genome sequence of S. sclerotiorum generated using Single Molecule Real-Time Sequencing technology with highly accurate annotations produced using an extensive RNA sequencing data set. We identified 70 effector candidates and have highlighted their in planta expression profiles. Furthermore, we characterized the genome architecture of S. sclerotiorum in comparison to plant pathogens that exhibit âtwo-speedâ genomes. We show that there is a significant association between positions of secreted proteins and regions with a high RIP index in S. sclerotiorum but we did not detect a correlation between secreted protein proportion and GC content. Neither did we detect a negative correlation between CDS content and secreted protein proportion across the S. sclerotiorum genome. We conclude that S. sclerotiorum exhibits subtle signatures of enhanced mutation of secreted proteins in specific genomic compartments as a result of transposition and RIP activity. However, these signatures are not observable at the whole-genome scale
The RadFxSat-2 Mission to Measure SEU Rates in FinFET Microelectronics
The RadFxSat-2 mission was launched January 17, 2021 with Virgin Orbit\u27s LauncherOne under the NASA ELaNa-20 initiative. RadFxSat-2 carries a radiation effects payload designed to investigate single event upsets (SEUs) in sub-65 nm commercial memories, including a FinFET-based memory. Sub-65 nm technologies have demonstrated enhanced sensitivity to low-energy protons, but current models have not considered low-energy protons as a source of SEUs. Missions utilizing the latest commercial technologies could experience a higher error rate than predicted. RadFxSat-2 was designed to assess SEU rates for FinFET SRAMs operated in low-Earth orbit (LEO), a proton-heavy environment. Details of the mission and data collected over the previous two years are presented. Results from RadFxSat-2 suggest that FinFET-based microelectronic technologies are suitable for high-performance, high-density storage in LEO
Phenylalanine induces Burkholderia cenocepacia phenylacetic acid catabolism through degradation to phenylacetyl-CoA in synthetic cystic fibrosis sputum medium
a b s t r a c t Synthetic cystic fibrosis sputum medium (SCFM) is rich in amino acids and supports robust growth of Burkholderia cenocepacia, a member of the Burkholderia cepacia complex (Bcc). Previous work demonstrated that B. cenocepacia phenylacetic acid (PA) catabolic genes are up-regulated during growth in SCFM and are required for full virulence in a Caenorhabditis elegans host model. In this work, we investigated the role of phenylalanine, one of the aromatic amino acids present in SCFM, as an inducer of the PA catabolic pathway. Phenylalanine degradation intermediates were used as sole carbon sources for growth and gene reporter experiments. In addition to phenylalanine and PA, phenylethylamine, phenylpyruvate, and 2-phenylacetamide were usable as sole carbon sources by wild type B. cenocepacia K56-2, but not by a PA catabolism-defective mutant. EMSA analysis showed that the binding of PaaR, the negative regulator protein of B. cenocepacia PA catabolism, to PA regulatory DNA could only be relieved by phenylacetyl-Coenzyme A (PA-CoA), but not by any of the putative phenylalanine degradation intermediates. Taken together, our results show that in B. cenocepacia, phenylalanine is catabolized to PA and induces PA catabolism through PA activation to PA-CoA. Thus, PaaR shares the same inducer with PaaX, the regulator of PA catabolism in Escherichia coli, despite belonging to a different protein family
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Genome-wide association study of primary open-angle glaucoma in continental and admixed African populations.
Primary open angle glaucoma (POAG) is a complex disease with a major genetic contribution. Its prevalence varies greatly among ethnic groups, and is up to five times more frequent in black African populations compared to Europeans. So far, worldwide efforts to elucidate the genetic complexity of POAG in African populations has been limited. We conducted a genome-wide association study in 1113 POAG cases and 1826 controls from Tanzanian, South African and African American study samples. Apart from confirming evidence of association at TXNRD2 (rs16984299; OR[T] 1.20; Pâ=â0.003), we found that a genetic risk score combining the effects of the 15 previously reported POAG loci was significantly associated with POAG in our samples (OR 1.56; 95% CI 1.26-1.93; Pâ=â4.79âĂâ10-5). By genome-wide association testing we identified a novel candidate locus, rs141186647, harboring EXOC4 (OR[A] 0.48; Pâ=â3.75âĂâ10-8), a gene transcribing a component of the exocyst complex involved in vesicle transport. The low frequency and high degree of genetic heterogeneity at this region hampered validation of this finding in predominantly West-African replication sets. Our results suggest that established genetic risk factors play a role in African POAG, however, they do not explain the higher disease load. The high heterogeneity within Africans remains a challenge to identify the genetic commonalities for POAG in this ethnicity, and demands studies of extremely large size
The glycinergic system in human startle disease: a genetic screening approach.
Human startle disease, also known as hyperekplexia (OMIM 149400), is a paroxysmal neurological disorder caused by defects in glycinergic neurotransmission. Hyperekplexia is characterised by an exaggerated startle reflex in response to tactile or acoustic stimuli which first presents as neonatal hypertonia, followed in some with episodes of life-threatening infantile apnoea. Genetic screening studies have demonstrated that hyperekplexia is genetically heterogeneous with several missense and nonsense mutations in the postsynaptic glycine receptor (GlyR) alpha1 subunit gene (GLRA1) as the primary cause. More recently, missense, nonsense and frameshift mutations have also been identified in the glycine transporter GlyT2 gene, SLC6A5, demonstrating a presynaptic component to this disease. Further mutations, albeit rare, have been identified in the genes encoding the GlyR beta subunit (GLRB), collybistin (ARHGEF9) and gephyrin (GPHN) - all of which are postsynaptic proteins involved in orchestrating glycinergic neurotransmission. In this review, we describe the clinical ascertainment aspects, phenotypic considerations and the downstream molecular genetic tools utilised to analyse both presynaptic and postsynaptic components of this heterogeneous human neurological disorder. Moreover, we will describe how the ancient startle response is the preserve of glycinergic neurotransmission and how animal models and human hyperekplexia patients have provided synergistic evidence that implicates this inhibitory system in the control of startle reflexes
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