110 research outputs found
HDE 245059: A Weak-Lined T Tauri Binary Revealed by Chandra and Keck
We present the Chandra High Energy Transmission Grating Spectrometer (HETGS)
and Keck observations of HDE 245059, a young weak-lined T Tauri star (WTTS),
member of the pre-main sequence group in the Lambda Orionis Cluster. Our high
spatial resolution, near-infrared observations with Keck reveal that HDE 245059
a binary separated by 0.87". Based on this new information we have obtained an
estimate of the masses of the binary components; 3M_{sun} and 2.5M_{sun} for
the north and south components, respectively. We have estimated the age of the
system to be ~2-3 Myr. We detect both components of the binary in the zeroth
order Chandra image and in the grating spectra. Our fits to the spectrum of the
binary have shown that the emission is dominated by a plasma between 8 and 15
MK, a soft component at 4 MK and a hard component at 50 MK are also detected.
The value of the hydrogen column density was low, 8 x 10^{19} cm^{-2}, likely
due to the clearing of the inner region of the Lambda Orionis cloud. The
abundance pattern shows an inverse First Ionization Potential (FIP) effect for
all elements from O to Fe, the only exception being Ca. A 3-T model was fitted
to the individual zeroth order spectra using the abundances derived for the
binary. We have also obtained several lines fluxes from the grating spectra.
The fits to the triplets show no evidence of high densities. We conclude that
the X-ray properties of the weak-lined T Tau binary HDE 245059 are similar to
those generally observed in other weak-lined T Tau stars. Although its
accretion history may have been affected by the clearing of the interstellar
material around Lambda Ori, its coronal properties appears not to have been
strongly modified.Comment: 12 pages, 10 figures Accepted for publication in Ap
Quantitative N- or C-Terminal Labelling of Proteins with Unactivated Peptides by Use of Sortases and a d-Aminopeptidase
Quantitative and selective labelling of proteins is widely used in both academic and industrial laboratories, and catalytic labelling of proteins using transpeptidases, such as sortases, has proved to be a popular strategy for such selective modification. A major challenge for this class of enzymes is that the majority of procedures require an excess of the labelling reagent or, alternatively, activated substrates rather than simple commercially sourced peptides. We report the use of a coupled enzyme strategy which enables quantitative N- and C-terminal labelling of proteins using unactivated labelling peptides. The use of an aminopeptidase in conjunction with a transpeptidase allows sequence-specific degradation of the peptide by-product, shifting the equilibrium to favor product formation, which greatly enhances the reaction efficiency. Subsequent optimisation of the reaction allows N-terminal labelling of proteins using essentially equimolar ratios of peptide label to protein and C-terminal labelling with only a small excess. Minimizing the amount of substrate required for quantitative labelling has the potential to improve industrial processes and facilitate the use of transpeptidation as a method for protein labelling
Particle-Vortex Duality and the Modular Group: Applications to the Quantum Hall Effect and Other 2-D Systems
We show how particle-vortex duality implies the existence of a large
non-abelian discrete symmetry group which relates the electromagnetic response
for dual two-dimensional systems in a magnetic field. For conductors with
charge carriers satisfying Fermi statistics (or those related to fermions by
the action of the group), the resulting group is known to imply many, if not
all, of the remarkable features of Quantum Hall systems. For conductors with
boson charge carriers (modulo group transformations) a different group is
predicted, implying equally striking implications for the conductivities of
these systems, including a super-universality of the critical exponents for
conductor/insulator and superconductor/insulator transitions in two dimensions
and a hierarchical structure, analogous to that of the quantum Hall effect but
different in its details. Our derivation shows how this symmetry emerges at low
energies, depending only weakly on the details of dynamics of the underlying
systems.Comment: 22 pages, LaTeX, 2 figures, uses revte
Emotional intelligence and British expatriates’ cross-cultural adjustment in international construction projects
© 2016 Informa UK Limited, trading as Taylor & Francis Group. Today’s internationalized business demands global mindset, intercultural sensitivity and the ability to skilfully negotiate through cross-cultural interactions. Therefore, the overall aim was to investigate the influence of emotional intelligence (EI) on cross-cultural adjustment (CCA) of British expatriates working on International Architectural, Engineering and Construction assignments in Sub-Saharan Africa, China, Middle East and Indian Sub-Continent. Specifically, the causal relationship between EI and three facets of CCA i.e. work, general and interaction adjustment was explored. A sequential exploratory mixed methods design was adopted. These include extensive review of existing literature, eighteen unstructured interviews, and questionnaire survey of 191 British expatriates operating in 29 different countries from the four regions under investigation. Structural equation modelling was used to assess the causal relationship between EI and CCA. Results show that EI accounted for 91, 64 and 24% of the variance in work, interaction and general adjustment respectively. Overall, the model was able to explain 60% variance in CCA, suggesting that EI competencies play a huge role in facilitating an expatriate understand and adapt to host country culture. The findings would help decision-makers (HR managers) during expatriate selection process, in understanding that along with technical skills, it is the emotional competencies that are crucial in assisting expatriates adjust to foreign way of life
Measurement of and charged current inclusive cross sections and their ratio with the T2K off-axis near detector
We report a measurement of cross section and the first measurements of the cross section
and their ratio
at (anti-)neutrino energies below 1.5
GeV. We determine the single momentum bin cross section measurements, averaged
over the T2K -flux, for the detector target material (mainly
Carbon, Oxygen, Hydrogen and Copper) with phase space restricted laboratory
frame kinematics of 500 MeV/c. The
results are and $\sigma(\nu)=\left( 2.41\
\pm0.022{\rm{(stat.)}}\pm0.231{\rm (syst.)}\ \right)\times10^{-39}^{2}R\left(\frac{\sigma(\bar{\nu})}{\sigma(\nu)}\right)=
0.373\pm0.012{\rm (stat.)}\pm0.015{\rm (syst.)}$.Comment: 18 pages, 8 figure
Elliptic hypergeometry of supersymmetric dualities II. Orthogonal groups, knots, and vortices
We consider Seiberg electric-magnetic dualities for 4d SYM
theories with SO(N) gauge group. For all such known theories we construct
superconformal indices (SCIs) in terms of elliptic hypergeometric integrals.
Equalities of these indices for dual theories lead both to proven earlier
special function identities and new conjectural relations for integrals. In
particular, we describe a number of new elliptic beta integrals associated with
the s-confining theories with the spinor matter fields. Reductions of some
dualities from SP(2N) to SO(2N) or SO(2N+1) gauge groups are described.
Interrelation of SCIs and the Witten anomaly is briefly discussed. Possible
applications of the elliptic hypergeometric integrals to a two-parameter
deformation of 2d conformal field theory and related matrix models are
indicated. Connections of the reduced SCIs with the state integrals of the knot
theory, generalized AGT duality for (3+3)d theories, and a 2d vortex partition
function are described.Comment: Latex, 58 pages; paper shortened, to appear in Commun. Math. Phy
Identification of common genetic risk variants for autism spectrum disorder
Autism spectrum disorder (ASD) is a highly heritable and heterogeneous group of neurodevelopmental phenotypes diagnosed in more than 1% of children. Common genetic variants contribute substantially to ASD susceptibility, but to date no individual variants have been robustly associated with ASD. With a marked sample-size increase from a unique Danish population resource, we report a genome-wide association meta-analysis of 18,381 individuals with ASD and 27,969 controls that identified five genome-wide-significant loci. Leveraging GWAS results from three phenotypes with significantly overlapping genetic architectures (schizophrenia, major depression, and educational attainment), we identified seven additional loci shared with other traits at equally strict significance levels. Dissecting the polygenic architecture, we found both quantitative and qualitative polygenic heterogeneity across ASD subtypes. These results highlight biological insights, particularly relating to neuronal function and corticogenesis, and establish that GWAS performed at scale will be much more productive in the near term in ASD.Peer reviewe
Search for Lorentz and CPT violation using sidereal time dependence of neutrino flavor transitions over a short baseline
A class of extensions of the Standard Model allows Lorentz and CPT violations, which can be identified
by the observation of sidereal modulations in the neutrino interaction rate. A search for such modulations
was performed using the T2K on-axis near detector. Two complementary methods were used in this study,
both of which resulted in no evidence of a signal. Limits on associated Lorentz and CPT-violating terms
from the Standard Model extension have been derived by taking into account their correlations in this
model for the first time. These results imply such symmetry violations are suppressed by a factor of more
than 10 20 at the GeV scale
Compilação atualizada das espécies de morcegos (Chiroptera) para a Amazônia Brasileira
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