pinecone/core-2020-05-10-deduplication huggingface dataset:
Cripto-independent Nodal signaling promotes positioning of the A-P axis in the early mouse embryo

During early mouse development, the TGF beta-related protein Nodal specifies the organizing centers that control the formation of the anterior-posterior (A-P) axis. EGF-CFC proteins are important components of the Nodal signaling pathway, most likely by acting as Nodal coreceptors. However, the extent to which Nodal activity depends on EGF-CFC proteins is still debated. Cripto is the earliest EGF-CFC gene expressed during mouse embryogenesis and is involved in both A-P axis orientation and mesoderm formation. To investigate the relation between Cripto and Nodal in the early mouse embryo, we removed the Nodal antagonist Cerberus 1 (Cer1) and simultaneously Cripto, by generating Cer1;Cripto double mouse mutants. We observed that two thirds of the Cer1,Cripto double mutants are rescued in processes that are severely compromised in Cripto(-/-) embryos, namely A-P axis orientation, anterior mesendoderm and posterior neuroectoderin formation. The observed rescue is strongly reduced in Cer1;Cripto;Nodal triple mutants, suggesting that Nodal can signal extensively in the absence of Cripto, if Cer1 is also inhibited. This signaling activity drives A-P axis positioning. Our results provide evidence for the existence. of Cripto-independent signaling mechanisms, by which Nodal controls axis specification in the early mouse embryo. (C) 2007 Elsevier Inc. All rights reserved
Achievement and behaviour in undergraduate mathematics: personality is a better predictor than gender

This is an Accepted Manuscript of an article published by Taylor & Francis in Research in Mathematics Education  on 28th January 2014, available online: http://wwww.tandfonline.com/10.1080/14794802.2013.874094We investigated two factors that predict students' achievement and behaviour in undergraduate mathematics: gender and personality. We found that gender predicted students' achievement and behaviour when considered in isolation, but ceased to be predictive when personality profiles were taken into account. Furthermore, personality accounted for significantly more variance in undergraduates' achievement and behaviour than did gender, but the converse was not the case. We therefore argue that personality provides the more productive lens through which to understand the behaviour of undergraduate mathematics students. We relate this finding to recent research emphasising gender differences in mathematics education, and suggest that researchers wishing to promote equity in participation at and beyond the undergraduate level should consider shifting their focus to individual differences in personality
Hyperfine mixing in electromagnetic decay of doubly heavy $bc$ baryons

We investigate the role of hyperfine mixing in the electromagnetic decay of
ground state doubly heavy $bc$ baryons. As in the case of a previous
calculation on $b\to c$ semileptonic decays of doubly heavy baryons, we find
large corrections to the electromagnetic decay widths due to this mixing.
Contrary to the weak case just mentioned, we find here that one can not use
electromagnetic width relations obtained in the infinite heavy quark mass limit
to experimentally extract information on the admixtures in a model independent
way.Comment: 9 Latex pages, 4 tables. A new reference added. A few misprints
  correcte
NLTT 41135: a field M-dwarf + brown dwarf eclipsing binary in a triple
  system, discovered by the MEarth observatory

We report the discovery of an eclipsing companion to NLTT 41135, a nearby M5
dwarf that was already known to have a wider, slightly more massive common
proper motion companion, NLTT 41136, at 2.4 arcsec separation. Analysis of
combined-light and radial velocity curves of the system indicates that NLTT
41135B is a 31-34 +/- 3 MJup brown dwarf (where the range depends on the
unknown metallicity of the host star) on a circular orbit. The visual M-dwarf
pair appears to be physically bound, so the system forms a hierarchical triple,
with masses approximately in the ratio 8:6:1. The eclipses are grazing,
preventing an unambiguous measurement of the secondary radius, but follow-up
observations of the secondary eclipse (e.g. with the James Webb Space
Telescope) could permit measurements of the surface brightness ratio between
the two objects, and thus place constraints on models of brown dwarfs.Comment: 15 pages, 6 figures, 10 tables, emulateapj format. Accepted for
  publication in Ap
Observations of the Blazar 3C 66A with the MAGIC Telescopes in
  Stereoscopic Mode

We report new observations of the intermediate-frequency peaked BL Lacertae
object 3C 66A with the MAGIC telescopes. The data sample we use were taken in
2009 December and 2010 January, and comprises 2.3 hr of good quality data in
stereoscopic mode. In this period, we find a significant signal from the
direction of the blazar 3C 66A. The new MAGIC stereoscopic system is shown to
play an essential role for the separation between 3C 66A and the nearby radio
galaxy 3C 66B, which is at a distance of only $6^\prime$. The derived integral
flux above $100\eh{GeV}$ is 8.3% of Crab Nebula flux and the energy spectrum is
reproduced by a power law of photon index $3.64 \pm 0.39_{\rm stat} \pm
0.25_{\rm sys}$. Within errors, this is compatible with the one derived by
VERITAS in 2009. From the spectra corrected for absorption by the extragalactic
background light, we only find small differences between the four models that
we applied, and constrain the redshift of the blazar to $z < 0.68$.Comment: Accepted for publication in Ap
Nonlinear Quantum Transport and Current Noise

We study nonequilibrium transport and noise in a generic dissipative
tight-binding model. Within a real-time path integral approach, we derive
formally exact series expressions in the number of tunneling events for the
noise valid for arbitrary bias, frequency and temperature. At zero temperature,
the low-frequency noise can be summed in analytic form. The resulting
Shiba-like $|\omega|$-singularity is a consequence of the $1/t^2$ decay law for
the current correlation function. At finite temperature, this singularity is
smoothed out.Comment: 9 pages, to appear in Ann. Phys. (Leipzig
Jordan-Brans-Dicke Quantum Wormholes and Coleman's Mechanism

We consider the quantum gravity and cosmology of a Jordan-Brans-Dicke theory,
predicted by string effective actions. We study its canonical formalism and
find that the constraint algebra is that of general relativity, as a
consequence of the general covariance of scalar-tensor theories. We also
analyze the problem of boundary conditions and propose that they must be
imposed in the Jordan frame, in which particles satisfy the strong equivalence
principle. Specifically, we discuss both Hartle-Hawking and wormhole boundary
conditions in the context of quantum cosmology. We find quantum wormhole
solutions for Jordan-Brans-Dicke gravity even in the absence of matter.
Wormholes may affect the constants of nature and, in particular, the
Brans-Dicke parameter. Following Coleman's mechanism, we find a probability
distribution which is strongly peaked at zero cosmological constant and
infinite Brans-Dicke parameter. That is, we recover general relativity as the
effective low energy theory of gravity.Comment: 22 pp, 1 figure available upon request, LaTeX. Conclusions have been
  change
Weak Matrix Elements on the Lattice --- Circa 1995

Status of weak matrix elements is reviewed. In particular, $\epspeps$,
$\bkastg$, $B_K$, $B_B$ and $B_{B_s}$ are discussed and the overall situation
with respect to the lattice effort and some of its phenomenological
implications are summarized. For $\epspeps$ the need for the relevant matrix
elements is stressed in view of the forthcoming improved experiments. For some
of the operators, (e.g.\ $O_6$), even bounds on their matrix elements would be
very helpful. On $\bkastg$, a constant behavior of $T_2$ appears disfavored
although dependence of $T_2$ could, of course, be milder than a simple pole.
Improved data is badly needed to settle this important issue firmly, especially
in view of its ramification for extractions of $V_{td}$ from $B\to\rho\gamma$.
On $B_K$, the preliminary result from JLQCD appears to contradict Sharpe \etal\
JLQCD data seems to fit very well to linear $a$ dependence and leads to an
appreciably lower value of $B_K$. Four studies of $B_K$ in the ``full''
($n_f=2$) theory indicate very little quenching effects on $B_K$; the full
theory value seems to be just a little less than the quenched result. Based on
expectations from HQET, analysis of the $B$-parameter ($B_{h\ell}$) for the
heavy-light mesons via
$B_{h\ell}={}$constant${}+{}$constants$^\prime/m_{h\ell}$ is suggested. A
summary of an illustrative sample of hadron matrix elements is given and
constraints on CKM parameters (e.g.\ $V_{td}/V_{ts}$), on the unitarity
triangle and on $x_s/x_d$, emerging from the lattice calculations along with
experimental results are briefly discussed. In quite a few cases, for the first
time, some indication of quenching errors on weak matrix elements are now
becoming available
Influence of nanoscale temperature rises on photoacoustic generation:
  discrimination between optical absorbers based on nonlinear photoacoustics at
  high frequency

In the thermoelastic regime, photoacoustic sensing of optical absorption
relies on conversion from light to acoustic energy via the coefficient of
thermal expansion \beta. In this work, we confront confront experimental
measurements to theoretical predictions of nonlinear photoacoustic generation
based on the dynamic variation of \beta(T) during the optical excitation of
absorbers in aqueous solution. The photoacoustic generation from solutions of
organic dye and gold nanospheres (with same optical densities), illuminated
with 532 nm nanosecond pulses, was detected using a high frequency ultrasound
transducer (center frequency 20 MHz). Photoacoustic emission was observed with
gold nanospheres at low fluence (a few mJ/cm2) for an equilibrium temperature
around 4{\deg}C, where the linear photoacoustic effect in water vanishes,
highlighting the nonlinear emission from the solution of nanospheres. Under the
same condition, no emission was observed with the absorbing organic dye. At a
fixed fluence of 5 mJ/cm2, the photoacoustic amplitude was studied as a
function of the equilibrium temperature from 2{\deg}C to 20{\deg}C. While the
photoacoustic amplitude from the organic dye followed \beta(T) in water and
vanished around 4{\deg}C, the photoacoustic amplitude from the gold nanospheres
remained significant over the whole temperature range. These experimental
results are shown to be in qualitative agreement with theoretical calculations
based on the nanoscale and nanosecond transient changes of the coefficient of
thermal expansion of water around the gold nanospheres. Our results suggest
that in the context of high frequency photoacoustic imaging, nanoparticles may
be discriminated from molecular absorbers based on either the nonlinear
fluence-dependence or the equilibrium temperature-dependence of the
photoacoustic amplitude
Antisymmetric tensor Z_p gauge symmetries in field theory and string
  theory

We consider discrete gauge symmetries in D dimensions arising as remnants of
broken continuous gauge symmetries carried by general antisymmetric tensor
fields, rather than by standard 1-forms. The lagrangian for such a general
${\bf Z}_p$ gauge theory can be described in terms of a $r$-form gauge field
made massive by a $(r-1)$-form, or other dual realizations, that we also
discuss. The theory contains charged topological defects of different
dimensionalities, generalizing the familiar charged particles and strings in
D=4. We describe realizations in string theory compactifications with torsion
cycles, or with background field strength fluxes. We also provide examples of
non-abelian discrete groups, for which the group elements are associated with
charged objects of different dimensionality.Comment: 16 pages; v2: references added and typos fixe
Keck-I MOSFIRE spectroscopy of compact star-forming galaxies at
  z$\gtrsim$2: High velocity dispersions in progenitors of compact quiescent
  galaxies

We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13
compact star-forming galaxies (SFGs) at redshift $2\leq z \leq2.5$ with star
formation rates of SFR$\sim$100M$_{\odot}$ y$^{-1}$ and masses of
log(M/M$_{\odot}$)$\sim10.8$. Their high integrated gas velocity dispersions of
$\sigma_{\rm{int}}$=230$^{+40}_{-30}$ km s$^{-1}$, as measured from emission
lines of H$_{\alpha}$ and [OIII], and the resultant
M$_{\star}-\sigma_{\rm{int}}$ relation and M$_{\star}$$-$M$_{\rm{dyn}}$ all
match well to those of compact quiescent galaxies at $z\sim2$, as measured from
stellar absorption lines. Since log(M$_{\star}$/M$_{\rm{dyn}}$)$=-0.06\pm0.2$
dex, these compact SFGs appear to be dynamically relaxed and more evolved,
i.e., more depleted in gas and dark matter ($<$13$^{+17}_{-13}$\%) than their
non-compact SFG counterparts at the same epoch. Without infusion of external
gas, depletion timescales are short, less than $\sim$300 Myr. This discovery
adds another link to our new dynamical chain of evidence that compact SFGs at
$z\gtrsim2$ are already losing gas to become the immediate progenitors of
compact quiescent galaxies by $z\sim2$.Comment: 12 pages, 7 figures, submitted to Ap
Dark matter monopoles, vectors and photons

In a secluded dark sector which is coupled to the Standard Model via a Higgs
portal interaction we arrange for the existence of 't Hooft-Polyakov magnetic
monopoles and study their implications for cosmology. We point out that a dark
sector which can accommodate stable monopoles will also contain massless dark
photons gamma' as well as charged massive vector bosons W'. The dark matter in
this scenario will be a combination of magnetically and electrically charged
species under the unbroken U(1) subgroup of the dark sector. We estimate the
cosmological production rate of monopoles and the rate of
monopole-anti-monopole annihilation and conclude that monopoles with masses of
few hundred TeV or greater, can produce sizeable contributions to the observed
dark matter relic density. We scan over the parameter space and compute the
relic density for monopoles and vector bosons. Turning to the dark photon
radiation, we compute their contribution to the measured density of
relativistic particles Neff and also apply observational constraints from the
Bullet cluster and other large scale galaxies on long-range interactions for
the self-interacting dark matter components made out of monopoles and out of
dark vector bosons. At scales relevant for dwarf galaxies we identify regions
on the parameter space where self-interacting monopole and vector dark mater
components can aid solving the core-cusp and the too-big-to-fail problems.Comment: 24 pages, 10 figures v2: Reference added; v3: minor typos corrected,
  References adde
Nonperturbative Bethe-Heitler pair creation in combined high- and
  low-frequency laser fields

The nonperturbative regime of electron-positron pair creation by a
relativistic proton beam colliding with a highly intense bichromatic laser
field is studied. The laser wave is composed of a strong low-frequency and a
weak high-frequency mode, with mutually orthogonal polarization vectors. We
show that the presence of the high-frequency field component can strongly
enhance the pair-creation rate. Besides, a characteristic influence of the
high-frequency mode on the angular and energy distributions of the created
particles is demonstrated, both in the nuclear rest frame and the laboratory
frame.Comment: 7 pages, 5 figure
Four dimensional superconformal theories from M5 branes

We study N=1 superconformal theories in four dimensions obtained wrapping M5
branes on a Riemann surface. We propose a method to determine from the spectral
curve the scaling dimension of chiral operators in the SCFT. Whenever the
R-symmetry has to be determined via a-maximization, our procedure allows us to
determine the charge of chiral operators under the "trial" R-symmetry. Our
proposal reduces to the correct prescription in the special case of N=2
theories of class S. We perform several consistency checks and apply our method
to study some new SCFT's such as N=1 deformations of Argyres-Douglas theories.Comment: 29 pages, 6 figures. References and clarifications added. Version
  published in JHE
Phase structure of $CP^{(N-1)}$ model with topological term

CP(N-1) model with topological term is numerically studied. The topological charge distribution P(Q) is calculated and then transformed to the partition function Z($\theta$) as a function of $\theta$ parameter. In the strong coupling region, P(Q) shows a gaussian behavior, which indicates a first order phase transition at $\theta =\pi$. In the weak coupling region, P(Q) deviates from gaussian. A bending behavior of resulting F($\theta$) at could be misled by large errors coming from the fourier transform of P(Q). Results are shown mainly for CP(3) case
Ruling out four-neutrino oscillation interpretations of the LSND anomaly?

Prompted by recent solar and atmospheric data, we re-analyze the four-neutrino description of current global neutrino oscillation data, including the LSND evidence for oscillations. The higher degree of rejection for non-active solar and atmospheric oscillation solutions implied by the SNO neutral current result as well as by the latest 1489-day Super-K atmospheric neutrino data allows us to rule out (2+2) oscillation schemes proposed to reconcile LSND with the rest of current neutrino oscillation data. Using an improved goodness of fit (gof) method especially sensitive to the combination of data sets we obtain a gof of only $1.6\times 10^{-6}$ for (2+2) schemes. Further, we re-evaluate the status of (3+1) oscillations using two different analyses of the LSND data sample. We find that also (3+1) schemes are strongly disfavoured by the data. Depending on the LSND analysis we obtain a gof of $5.6\times 10^{-3}$ or $7.6\times 10^{-5}$. This leads to the conclusion that all four-neutrino descriptions of the LSND anomaly, both in (2+2) as well as (3+1) realizations, are highly disfavoured. Our analysis brings the LSND hint to a more puzzling status
Speed of Light in Non--Trivial Vacua

We unify all existing results on the change of the speed of low--energy
photons due to modifications of the vacuum, finding that it is given by a
universal constant times the quotient of the difference of energy densities
between the usual and modified vacua over the mass of the electron to the
fourth power. Whether photons move faster or slower than $c$ depends only on
the lower or higher energy density of the modified vacuum, respectively.
Physically, a higher energy density is characterized by the presence of
additional particles (real or virtual) in the vacuum whereas a lower one stems
from the absence of some virtual modes. We then carry out a systematic study of
the speed of propagation of massless particles for several field theories up to
two loops on a thermal vacuum. Only low--energy massless particles
corresponding to a massive theory show genuine modifications of their speed
while remaining massless. All other modifications are mass-related, or running
mass-related. We also develop a formalism for the Casimir vacuum which
parallels the thermal one and check that photons travel faster than $c$ between
plates.Comment: 24 p., plain te
Nuclear transparencies in relativistic A(e,e'p) models

Relativistic and unfactorized calculations for the nuclear transparency
extracted from exclusive A(e,e'p) reactions for 0.3 \leq Q^2 \leq 10 (GeV/c)^2
are presented for the target nuclei C, Si, Fe and Pb. For Q^2 \geq 0.6
(GeV/c)^2, the transparency results are computed within the framework of the
recently developed relativistic multiple-scattering Glauber approximation
(RMSGA). The target-mass and Q^2 dependence of the RMSGA predictions are
compared with relativistic distorted-wave impulse approximation (RDWIA)
calculations. Despite the very different model assumptions underlying the
treatment of the final-state interactions in the RMSGA and RDWIA frameworks,
they predict comparable nuclear transparencies for kinematic regimes where both
models are applicable.Comment: 15 pages, 4 figure
Dynamics of the Landau-Pomeranchuk-Migdal Effect in Au+Au Collisions at
  200 AGeV

We study the role played by the Landau-Pomeranchuk-Midgal (LPM) effect in
relativistic collisions of hadrons and heavy nuclei, within a parton cascade
model. We find that the LPM effect strongly affects the gluon multiplication
due to radiation and considerably alters the space-time evolution of the
dynamics of the collision. It ensures a multiplicity distribution of hadrons in
aggreement with the experimental proton-proton data. We study the production of
single photons in relativistic heavy ion collisions and find that the inclusion
of LPM suppression leads to a reduction in the single photon yield at small and
intermediate transverse momenta. The parton cascade calculation of the single
photon yield including the LPM effect is shown to be in good agreement with the
recent PHENIX data taken at the Relativistic Heavy-Ion Collider.Comment: 12 pages, 4 figure
Predictive $CP$ Violating Relations for Charmless Two-body Decays of
  Beauty Baryons $\Xi^{-,\;0}_b$ and $\Lambda_b^0$ With Flavor $SU(3)$ Symmetry

Several baryons containing a heavy b-quark have been discovered. The decays
of these states provide new platform for testing the standard model (SM). We
study $CP$ violation in SM for charmless two-body decays of the flavor $SU(3)$
anti-triplet beauty baryon (b-baryon) ${\cal B} =
(\Xi^-_b,\;\Xi^0_b,\;\Lambda_b^0)$ in a model independent way. We found, in the
flavor $SU(3)$ symmetry limit, a set of new predictive relations among the
branching ratio $Br$ and $CP$ asymmetry $A_{CP}$ for $\cal B$ decays, such as
$A_{CP}(\Xi_b^-\to K^0 \Xi^-)/A_{CP}(\Xi_b^-\to \bar K^0 \Sigma^-) = -
Br(\Xi_b^- \to \bar K^0 \Sigma^-)/Br(\Xi_b^- \to K^0 \Sigma^-)$,
$A_{CP}(\Lambda_b^0 \to \pi^- p)/A_{CP} (\Xi^0_b \to K^- \Sigma^+) =
-Br(\Xi^0_b \to K^- \Sigma^+)\tau_{\Lambda_b^0}/Br(\Lambda_b^0 \to \pi^-
p)\tau_{\Xi^0_b}$,and $A_{CP}(\Lambda_b^0 \to K^- p)/ A_{CP} (\Xi^0_b \to \pi^-
\Sigma^+) = -Br(\Xi^0_b \to \pi^- \Sigma^+)\tau_{\Lambda_b^0}/ Br(\Lambda_b^0
\to K^- p)\tau_{\Xi^0_b}$. Future data from LHCb can test these relations and
also other relations found.Comment: 13 pages, no figure, 6 tables, several missing terms in eq.11 are
  adde
IR fixed points in $SU(3)$ gauge Theories

We propose a novel RG method to specify the location of the IR fixed point in
lattice gauge theories and apply it to the $SU(3)$ gauge theories with $N_f$
fundamental fermions. It is based on the scaling behavior of the propagator
through the RG analysis with a finite IR cut-off, which we cannot remove in the
conformal field theories in sharp contrast with the confining theories. The
method also enables us to estimate the anomalous mass dimension in the
continuum limit at the IR fixed point. We perform the program for $N_f=16, 12,
8 $ and $N_f=7$ and indeed identify the location of the IR fixed points in all
cases.Comment: 7 pages, 7 figures, 1 table: the scale of the y axis in Figs..1-4
  change; minor modifications as appear in PL