1,802 research outputs found
Molecular evidence for gender differences in the migratory behaviour of a small seabird
Molecular sexing revealed an unexpectedly strong female bias in the sex ratio of pre-breeding European Storm Petrels (Hydrobates pelagicus), attracted to playback of conspecific calls during their northwards migration past SW Europe. This bias was consistent across seven years, ranging from 80.8% to 89.7% female (mean annual sex ratio ± SD = 85.5% female ±4.1%). The sex ratio did not differ significantly from unity (i.e., 50% female) among (i) Storm Petrel chicks at a breeding colony in NW France, (ii) adults found dead on beaches in Southern Portugal, (iii) breeding birds attending nest burrows in the UK, captured by hand, and (iv) adults captured near a breeding colony in the UK using copies of the same sound recordings as used in Southern Europe, indicating that females are not inherently more strongly attracted to playback calls than males. A morphological discriminant function analysis failed to provide a good separation of the sexes, showing the importance of molecular sexing for this species. We found no sex difference in the seasonal or nocturnal timing of migration past Southern Europe, but there was a significant tendency for birds to be caught in sex-specific aggregations. The preponderance of females captured in Southern Europe suggests that the sexes may differ in migration route or in their colony-prospecting behaviour during migration, at sites far away from their natal colonies. Such differences in migration behaviour between males and females are poorly understood but have implications for the vulnerability of seabirds to pollution and environmental change at sea during the non-breeding season
The C-Band All-Sky Survey: Instrument design, status, and first-look data
The C-Band All-Sky Survey (C-BASS) aims to produce sensitive, all-sky maps of
diffuse Galactic emission at 5 GHz in total intensity and linear polarization.
These maps will be used (with other surveys) to separate the several
astrophysical components contributing to microwave emission, and in particular
will allow an accurate map of synchrotron emission to be produced for the
subtraction of foregrounds from measurements of the polarized Cosmic Microwave
Background. We describe the design of the analog instrument, the optics of our
6.1 m dish at the Owens Valley Radio Observatory, the status of observations,
and first-look data.Comment: 10 pages, 11 figures, published in Proceedings of SPIE MIllimeter,
Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
(2010), Vol. 7741, 77411I-1 - 77411I-1
Spectroscopy of Broad Line Blazars from 1LAC
We report on optical spectroscopy of 165 Flat Spectrum Radio Quasars (FSRQs)
in the Fermi 1LAC sample, which have helped allow a nearly complete study of
this population. Fermi FSRQ show significant evidence for non-thermal emission
even in the optical; the degree depends on the gamma-ray hardness. They also
have smaller virial estimates of hole mass than the optical quasar sample. This
appears to be largely due to a preferred (axial) view of the gamma-ray FSRQ and
non-isotropic (H/R ~ 0.4) distribution of broad-line velocities. Even after
correction for this bias, the Fermi FSRQ show higher mean Eddington ratios than
the optical population. A comparison of optical spectral properties with Owens
Valley Radio Observatory radio flare activity shows no strong correlation.Comment: Accepted for publication in Ap
Spectroscopy of the Largest Ever γ-Ray-selected BL Lac Sample
We report on spectroscopic observations covering most of the 475 BL Lacs in the second Fermi Large Area Telescope (LAT) catalog of active galactic nuclei (AGNs). Including archival measurements (correcting several erroneous literature values) we now have spectroscopic redshifts for 44% of the BL Lacs. We establish firm lower redshift limits via intervening absorption systems and statistical lower limits via searches for host galaxies for an additional 51% of the sample leaving only 5% of the BL Lacs unconstrained. The new redshifts raise the median spectroscopic z from 0.23 to 0.33 and include redshifts as large as z = 2.471. Spectroscopic redshift minima from intervening absorbers have z = 0.70, showing a substantial fraction at large z and arguing against strong negative evolution. We find that detected BL Lac hosts are bright ellipticals with black hole masses M_• ~ 10^(8.5) – 10^9, substantially larger than the mean of optical AGNs and LAT Flat Spectrum Radio Quasar samples. A slow increase in M_• with z may be due to selection bias. We find that the power-law dominance of the optical spectrum extends to extreme values, but this does not strongly correlate with the γ-ray properties, suggesting that strong beaming is the primary cause of the range in continuum dominance
Chromosome-specific KASP markers for detecting Amblyopyrum muticum segments in wheat introgression lines
Many wild-relative species are being used in prebreeding programs to increase the genetic diversity of wheat (Triticum aestivum L.). Genotyping tools such as single nucleotide polymorphism (SNP)-based arrays and molecular markers have been widely used to characterize wheat–wild relative introgression lines. However, due to the polyploid nature of the recipient wheat genome, it is difficult to develop SNP-based Kompetitive allele-specific polymerase chain reaction (KASP) markers that are codominant to track the introgressions from the wild species. Previous attempts to develop KASP markers have involved both exome- and polymerase chain reaction (PCR)-amplicon-based sequencing of the wild species. But chromosome-specific KASP assays have been hindered by homoeologous SNPs within the wheat genome. This study involved whole genome sequencing of the diploid wheat wild relative Amblyopyrum muticum (Boiss.) Eig and development of a de novo SNP discovery pipeline that generated ∼38,000 SNPs in unique wheat genome sequences. New assays were designed to increase the density of Am. muticum polymorphic KASP markers. With a goal of one marker per 60 Mbp, 335 new KASP assays were validated as diagnostic for Am. muticum in a wheat background. Together with assays validated in previous studies, 498 well distributed chromosome-specific markers were used to recharacterize previously genotyped wheat–Am. muticum doubled haploid (DH) introgression lines. The chromosome-specific nature of the KASP markers allowed clarification of which wheat chromosomes were involved with recombination events or substituted with Am. muticum chromosomes and the higher density of markers allowed detection of new small introgressions in these DH lines
Chromosome-specific KASP markers for detecting Amblyopyrum muticum segments in wheat introgression lines
Many wild-relative species are being used in prebreeding programs to increase the genetic diversity of wheat (Triticum aestivum L.). Genotyping tools such as single nucleotide polymorphism (SNP)-based arrays and molecular markers have been widely used to characterize wheat–wild relative introgression lines. However, due to the polyploid nature of the recipient wheat genome, it is difficult to develop SNP-based Kompetitive allele-specific polymerase chain reaction (KASP) markers that are codominant to track the introgressions from the wild species. Previous attempts to develop KASP markers have involved both exome- and polymerase chain reaction (PCR)-amplicon-based sequencing of the wild species. But chromosome-specific KASP assays have been hindered by homoeologous SNPs within the wheat genome. This study involved whole genome sequencing of the diploid wheat wild relative Amblyopyrum muticum (Boiss.) Eig and development of a de novo SNP discovery pipeline that generated ∼38,000 SNPs in unique wheat genome sequences. New assays were designed to increase the density of Am. muticum polymorphic KASP markers. With a goal of one marker per 60 Mbp, 335 new KASP assays were validated as diagnostic for Am. muticum in a wheat background. Together with assays validated in previous studies, 498 well distributed chromosome-specific markers were used to recharacterize previously genotyped wheat–Am. muticum doubled haploid (DH) introgression lines. The chromosome-specific nature of the KASP markers allowed clarification of which wheat chromosomes were involved with recombination events or substituted with Am. muticum chromosomes and the higher density of markers allowed detection of new small introgressions in these DH lines
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Improved efficacy of pembrolizumab combined with soluble EphB4-albumin in HPV-negative EphrinB2 positive head neck squamous cell carcinoma
ObjectivePatients with relapsed or metastatic head and neck squamous cell carcinoma (HNSCC) after primary local therapy have low response rates with cetuximab, systemic chemotherapy or check point inhibitor therapy. Novel combination therapies with the potential to improve outcomes for patients with HNSCC is an area of high unmet need.MethodsThis is a phase II single-arm clinical trial of locally advanced or metastatic HNSCC patients treated with a combination of soluble EphB4-human serum albumin (sEphB4-HSA) fusion protein and pembrolizumab after platinum-based chemotherapy with up to 2 prior lines of treatment. The primary endpoints were safety and tolerability and the primary efficacy endpoint was overall response rate (ORR). Secondary endpoints included progression free survival (PFS) and overall survival (OS). HPV status and EphrinB2 expression were evaluated for outcome.ResultsTwenty-five patients were enrolled. Median follow up was 40.4 months (range 9.8 - 40.4). There were 6 responders (ORR 24%). There were 5 responders in the 11 HPV-negative and EphrinB2 positive patients, (ORR 45%) with 2 of these patients achieving a complete response (CR). The median PFS in HPV-negative/EphrinB2 positive patients was 3.2 months (95% CI 1.1, 7.3). Median OS in HPV-negative/EphrinB2 positive patients was 10.9 months (95% CI 2.0, 13.7). Hypertension, transaminitis and fatigue were the most common toxicities.DiscussionThe combination of sEphB4-HSA and pembrolizumab has a favorable toxicity profile and favorable activity particularly among HPV-negative EphrinB2 positive patients with HNSCC
Introgression of the Triticum timopheevii genome into wheat detected by chromosome-specific Kompetitive allele specific PCR markers
Triticum timopheevii (2n = 28, AtAtGG) is a tetraploid wild relative species with great potential to increase the genetic diversity of hexaploid wheat Triticum aestivum (2n = 42, AABBDD) for various important agronomic traits. A breeding scheme that propagated advanced backcrossed populations of wheat-T. timopheevii introgression lines through further backcrossing and self-fertilisation resulted in the generation of 99 introgression lines (ILs) that carried 309 homozygous segments from the At and G subgenomes of T. timopheevii. These introgressions contained 89 and 74 unique segments from the At and G subgenomes, respectively. These overlapping segments covered 98.9% of the T. timopheevii genome that has now been introgressed into bread wheat cv. Paragon including the entirety of all T. timopheevii chromosomes via varying sized segments except for chromosomes 3At, 4G, and 6G. Homozygous ILs contained between one and eight of these introgressions with an average of three per introgression line. These homozygous introgressions were detected through the development of a set of 480 chromosome-specific Kompetitive allele specific PCR (KASP) markers that are well-distributed across the wheat genome. Of these, 149 were developed in this study based on single nucleotide polymorphisms (SNPs) discovered through whole genome sequencing of T. timopheevii. A majority of these KASP markers were also found to be T. timopheevii subgenome specific with 182 detecting At subgenome and 275 detecting G subgenome segments. These markers showed that 98% of the At segments had recombined with the A genome of wheat and 74% of the G genome segments had recombined with the B genome of wheat with the rest recombining with the D genome of wheat. These results were validated through multi-colour in situ hybridisation analysis. Together these homozygous wheat-T. timopheevii ILs and chromosome-specific KASP markers provide an invaluable resource to wheat breeders for trait discovery to combat biotic and abiotic stress factors affecting wheat production due to climate change
Blazars in the Fermi Era: The OVRO 40-m Telescope Monitoring Program
The Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope
provides an unprecedented opportunity to study gamma-ray blazars. To capitalize
on this opportunity, beginning in late 2007, about a year before the start of
LAT science operations, we began a large-scale, fast-cadence 15 GHz radio
monitoring program with the 40-m telescope at the Owens Valley Radio
Observatory (OVRO). This program began with the 1158 northern (declination>-20
deg) sources from the Candidate Gamma-ray Blazar Survey (CGRaBS) and now
encompasses over 1500 sources, each observed twice per week with a ~4 mJy
(minimum) and 3% (typical) uncertainty. Here, we describe this monitoring
program and our methods, and present radio light curves from the first two
years (2008 and 2009). As a first application, we combine these data with a
novel measure of light curve variability amplitude, the intrinsic modulation
index, through a likelihood analysis to examine the variability properties of
subpopulations of our sample. We demonstrate that, with high significance
(7-sigma), gamma-ray-loud blazars detected by the LAT during its first 11
months of operation vary with about a factor of two greater amplitude than do
the gamma-ray-quiet blazars in our sample. We also find a significant (3-sigma)
difference between variability amplitude in BL Lacertae objects and
flat-spectrum radio quasars (FSRQs), with the former exhibiting larger
variability amplitudes. Finally, low-redshift (z<1) FSRQs are found to vary
more strongly than high-redshift FSRQs, with 3-sigma significance. These
findings represent an important step toward understanding why some blazars emit
gamma-rays while others, with apparently similar properties, remain silent.Comment: 23 pages, 24 figures. Submitted to ApJ
Enhanced response inhibition during intensive meditation training predicts improvements in self-reported adaptive socioemotional functioning.
We examined the impact of training-induced improvements in self-regulation, operationalized in terms of response inhibition, on longitudinal changes in self-reported adaptive socioemotional functioning. Data were collected from participants undergoing 3 months of intensive meditation training in an isolated retreat setting (Retreat 1) and a wait-list control group that later underwent identical training (Retreat 2). A 32-min response inhibition task (RIT) was designed to assess sustained self-regulatory control. Adaptive functioning (AF) was operationalized as a single latent factor underlying self-report measures of anxious and avoidant attachment, mindfulness, ego resilience, empathy, the five major personality traits (extroversion, agreeableness, conscientiousness, neuroticism, and openness to experience), diffi-culties in emotion regulation, depression, anxiety, and psychological well-being. Participants in Retreat 1 improved in RIT performance and AF over time whereas the controls did not. The control participants later also improved on both dimensions during their own retreat (Retreat 2). These improved levels of RIT performance and AF were sustained in follow-up assessments conducted approximately 5 months after the training. Longitudinal dynamic models with combined data from both retreats showed that improvement in RIT performance during training influenced the change in AF over time, which is consistent with a key claim in the Buddhist literature that enhanced capacity for self-regulation is an important precursor of changes in emotional well-being
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