pinecone/core-2020-05-10-deduplication huggingface dataset:
The validity of quasi steady-state approximations in discrete stochastic
  simulations

In biochemical networks, reactions often occur on disparate timescales and
can be characterized as either "fast" or "slow." The quasi-steady state
approximation (QSSA) utilizes timescale separation to project models of
biochemical networks onto lower-dimensional slow manifolds. As a result, fast
elementary reactions are not modeled explicitly, and their effect is captured
by non-elementary reaction rate functions (e.g. Hill functions). The accuracy
of the QSSA applied to deterministic systems depends on how well timescales are
separated. Recently, it has been proposed to use the non-elementary rate
functions obtained via the deterministic QSSA to define propensity functions in
stochastic simulations of biochemical networks. In this approach, termed the
stochastic QSSA, fast reactions that are part of non-elementary reactions are
not simulated, greatly reducing computation time. However, it is unclear when
the stochastic QSSA provides an accurate approximation of the original
stochastic simulation. We show that, unlike the deterministic QSSA, the
validity of the stochastic QSSA does not follow from timescale separation
alone, but also depends on the sensitivity of the non-elementary reaction rate
functions to changes in the slow species. The stochastic QSSA becomes more
accurate when this sensitivity is small. Different types of QSSAs result in
non-elementary functions with different sensitivities, and the total QSSA
results in less sensitive functions than the standard or the pre-factor QSSA.
We prove that, as a result, the stochastic QSSA becomes more accurate when
non-elementary reaction functions are obtained using the total QSSA. Our work
provides a novel condition for the validity of the QSSA in stochastic
simulations of biochemical reaction networks with disparate timescales.Comment: 21 pages, 4 figure
Renormalization group analysis of the three-dimensional Gross-Neveu
  model at finite temperature and density

The Renormalization Group flow equations obtained by means of a proper time
regulator are used to analyze the restoration of the discrete chiral symmetry
at non-zero density and temperature in the Gross-Neveu model in d=2+1
dimensions. The effects of the wave function renormalization of the auxiliary
scalar field on the transition have been studied. The analysis is performed for
a number of fermion flavors N_f=12 and the limit of large N_f is also
considered. The results are compared with those coming from lattice
simulations.Comment: Latex file, 12 pages, 2 eps figures, minor changes, added references,
  published versio
3-Branes and Uniqueness of the Salam-Sezgin Vacuum

We prove the uniqueness of the supersymmetric Salam-Sezgin
(Minkowski)_4\times S^2 ground state among all nonsingular solutions with a
four-dimensional Poincare, de Sitter or anti-de Sitter symmetry. We construct
the most general solutions with an axial symmetry in the two-dimensional
internal space, and show that included amongst these is a family that is
non-singular away from a conical defect at one pole of a distorted 2-sphere.
These solutions admit the interpretation of 3-branes with negative tension.Comment: Latex, 12 pages; typos corrected, discussion of brane tensions
  amende
Search for the $B_c$ meson in hadronic $Z^0$ decays

A search for decays of the B_c meson was performed using data collected from 1990-1995 with the OPAL detector on or near the Z peak at LEP. The decay channels B_c^+ -> J/psi pi^+, B_c^+ -> J/psi a_1^+ and B_c^+ -> J/psi ell^+ nu were investigated, where ell denotes an electron or a muon. Two candidates are observed in the mode B_c^+ -> J/psi pi^+, with an estimated background of (0.63 +/- 0.20) events. The weighted mean of the masses of the two candidates is (6.32 +/- 0.06) GeV/c^2, which is consistent with the predicted mass of the B_c meson. One candidate event is observed in the mode B_c^+ -> J/psi ell^+ nu with an estimated background of (0.82 +/- 0.19) events. No candidate events are observed in the B_c^+ -> J/psi a_1^+ decay mode, with an estimated background of (1.10 +/- 0.22) events. Upper bounds at the 90% confidence level are set on the production rates for these processes
Extreme Energy Cosmic Rays (EECR) Observation Capabilities of an "Airwatch from Space" Mission

The longitudinal development and other characteristics of the EECR induced atmospheric showers can be studied from space by detecting the fluorescence light induced in the atmospheric nitrogen. According to the Airwatch concept a single fast detector can be used for measuring both intensity and time development of the streak of fluorescence light produced by the atmospheric shower induced by an EECR. In the present communication the detection capabilities for the EECR observation from space are discussed
Picard-Fuchs Ordinary Differential Systems in $N = 2$ Supersymmetric Yang-Mills Theories

In general, Picard-Fuchs systems in N=2 supersymmetric Yang-Mills theories are realized as a set of simultaneous partial differential equations. However, if the QCD scale parameter is used as unique independent variable instead of moduli, the resulting Picard-Fuchs systems are represented by a single ordinary differential equation (ODE) whose order coincides with the total number of independent periods. This paper discusses some properties of these Picard-Fuchs ODEs. In contrast with the usual Picard-Fuchs systems written in terms of moduli derivatives, there exists a Wronskian for this ordinary differential system and this Wronskian produces a new relation among periods, moduli and QCD scale parameter, which in the case of SU(2) is reminiscent of scaling relation of prepotential. On the other hand, in the case of the SU(3) theory, there are two kinds of ordinary differential equations, one of which is the equation directly constructed from periods and the other is derived from the SU(3) Picard-Fuchs equations in moduli derivatives identified with Appell's $F_4$ hypergeometric system, i.e., Burchnall's fifth order ordinary differential equation published in 1942. It is shown that four of the five independent solutions to the latter equation actually correspond to the four periods in the SU(3) gauge theory and the closed form of the remaining one is established by the SU(3) Picard-Fuchs ODE. The formula for this fifth solution is a new one
Comparison of Isoscalar Vector Meson Production Cross Sections in
  Proton-Proton Collisions

The reaction $ pp\to pp\bf \omega$ was investigated with the TOF
spectrometer, which is an external experiment at the accelerator COSY
(Forschungszentrum J\"ulich, Germany). Total as well as differential cross
sections were determined at an excess energy of $93 MeV$ ($p_{beam}=2950
MeV/c$). Using the total cross section of $(9.0\pm 0.7 \pm1.1) \mu b$ for the
reaction $ pp\to pp\omega$ determined here and existing data for the reaction
$pp\to pp\bf \phi$, the ratio
$\mathcal{R}_{\phi/\omega}=\sigma_\phi/\sigma_\omega$ turns out to be
significantly larger than expected by the Okubo-Zweig-Iizuka (OZI) rule. The
uncertainty of this ratio is considerably smaller than in previous
determinations. The differential distributions show that the $\omega$
production is still dominated by S-wave production at this excess energy,
however higher partial waves clearly contribute. A comparison of the measured
angular distributions for $\omega$ production to published distributions for
$\phi$ production at $83 MeV$ shows that the data are consistent with an
identical production mechanism for both vector mesons
The Origin of Large-p_T pi^0 Suppression at RHIC

We present results for inclusive $\pi^0$ production in proton-proton and in
Au-Au at RHIC energy $\sqrt s=200$ GeV. We use next-to-leading order
perturbative QCD calculation and we include nuclear effects such as parton
energy loss and nuclear shadowing. We consider the ratio of $\pi^0$
distribution in Au-Au and p-p collisions for $p_T > 3$ GeV for three cases of
parton energy loss: 1) constant parton energy loss per parton scattering,
$\epsilon^a_n=const$, 2) Landau-Pomeranchuk-Migdal energy-dependent energy
loss, $\epsilon^a_n \sim \sqrt E^a_n$ and 3) Bethe-Heitler energy-dependent
energy loss, $\epsilon^a_n \sim E^a_n$. We show that recently observed
suppression of $\pi^0$ production in Au-Au collisions at RHIC, which is found
to increase with $p_T$ increasing from 3GeV to 8GeV, can be reproduced by
$\epsilon^a_n=0.06 E^a_n$. We show that the ratio of prompt photons to neutral
pions produced in Au-Au collisions at RHIC has a strong $p_T$ dependence
approaching one at $p_T\sim 10$GeV.Comment: minor corrections; version accepted for publication in Physics
  Letters
ALMA detection of [CII] 158 micron emission from a strongly lensed z=2
  star-forming galaxy

Our objectives are to determine the properties of the interstellar medium
(ISM) and of star-formation in typical star-forming galaxies at high redshift.
Following up on our previous multi-wavelength observations with HST, Spitzer,
Herschel, and the Plateau de Bure Interferometer (PdBI), we have studied a
strongly lensed z=2.013 galaxy, the arc behind the galaxy cluster MACS
J0451+0006, with ALMA to measure the [CII] 158 micron emission line, one of the
main coolants of the ISM. [CII] emission from the southern part of this galaxy
is detected at 10 $\sigma$. Taking into account strong gravitational lensing,
which provides a magnification of $\mu=49$, the intrinsic lensing-corrected
[CII]158 micron luminosity is $L(CII)=1.2 \times 10^8 L_\odot$. The observed
ratio of [CII]-to-IR emission, $L(CII)/L(FIR) \approx (1.2-2.4) \times
10^{-3}$, is found to be similar to that in nearby galaxies. The same also
holds for the observed ratio $L(CII)/L(CO)=2.3 \times 10^3$, which is
comparable to that of star-forming galaxies and active galaxy nuclei (AGN) at
low redshift. We utilize strong gravitational lensing to extend diagnostic
studies of the cold ISM to an order of magnitude lower luminosity ($L(IR) \sim
(1.1-1.3) \times 10^{11} L_\odot$) and SFR than previous work at high redshift.
While larger samples are needed, our results provide evidence that the cold ISM
of typical high redshift galaxies has physical characteristics similar to
normal star forming galaxies in the local Universe.Comment: 5 pages, 4 figures. Accepted for publication in Astronomy &
  Astrophysics, Letter
Angular momentum redistribution by mixed modes in evolved low-mass
  stars. II. Spin-down of the core of red giants induced by mixed modes

The detection of mixed modes in subgiants and red giants by the CoRoT and
\emph{Kepler} space-borne missions allows us to investigate the internal
structure of evolved low-mass stars. In particular, the measurement of the mean
core rotation rate as a function of the evolution places stringent constraints
on the physical mechanisms responsible for the angular momentum redistribution
in stars. It showed that the current stellar evolution codes including the
modelling of rotation fail to reproduce the observations. An additional
physical process that efficiently extracts angular momentum from the core is
thus necessary.
  Our aim is to assess the ability of mixed modes to do this. To this end, we
developed a formalism that provides a modelling of the wave fluxes in both the
mean angular momentum and the mean energy equations in a companion paper. In
this article, mode amplitudes are modelled based on recent asteroseismic
observations, and a quantitative estimate of the angular momentum transfer is
obtained. This is performed for a benchmark model of 1.3 $M_{\odot}$ at three
evolutionary stages, representative of the evolved pulsating stars observed by
CoRoT and Kepler.
  We show that mixed modes extract angular momentum from the innermost regions
of subgiants and red giants. However, this transport of angular momentum from
the core is unlikely to counterbalance the effect of the core contraction in
subgiants and early red giants. In contrast, for more evolved red giants, mixed
modes are found efficient enough to balance and exceed the effect of the core
contraction, in particular in the hydrogen-burning shell. Our results thus
indicate that mixed modes are a promising candidate to explain the observed
spin-down of the core of evolved red giants, but that an other mechanism is to
be invoked for subgiants and early red giants.Comment: Accepted in A&A, 7 pages, 8 figure
An Elemental Assay of Very, Extremely, and Ultra Metal-Poor Stars

We present a high-resolution elemental-abundance analysis for a sample of 23
very metal-poor (VMP; [Fe/H] < -2.0) stars, 12 of which are extremely
metal-poor (EMP; [Fe/H] < -3.0), and 4 of which are ultra metal-poor (UMP;
[Fe/H] < -4.0). These stars were targeted to explore differences in the
abundance ratios for elements that constrain the possible astrophysical sites
of element production, including Li, C, N, O, the alpha-elements, the iron-peak
elements, and a number of neutron-capture elements. This sample substantially
increases the number of known carbon-enhanced metal-poor (CEMP) and
nitrogen-enhanced metal-poor (NEMP) stars -- our program stars include eight
that are considered "normal" metal-poor stars, six CEMP-no stars, five CEMP-s
stars, two CEMP-r stars, and two CEMP-r/s stars. One of the CEMP-$r$ stars and
one of the CEMP-r/s stars are possible NEMP stars. We detect lithium for three
of the six CEMP-no stars, all of which are Li-depleted with respect to the
Spite plateau. The majority of the CEMP stars have [C/N] > 0. The stars with
[C/N] < 0 suggest a larger degree of mixing; the few CEMP-no stars that exhibit
this signature are only found at [Fe/H] < -3.4, a metallicity below which we
also find the CEMP-no stars with large enhancements in Na, Mg, and Al. We
confirm the existence of two plateaus in the absolute carbon abundances of CEMP
stars, as suggested by Spite et al. We also present evidence for a "floor" in
the absolute Ba abundances of CEMP-no stars at A(Ba)~ -2.0.Comment: 20 pages, 16 figures, Accepted for publication in Ap
The primary cilium influences interleukin-1Î²-induced NFÎºB signalling by regulating IKK activity.

The primary cilium is an organelle acting as a master regulator of cellular signalling. We have previously shown that disruption of primary cilia assembly, through targeting intraflagellar transport, is associated with muted nitric oxide and prostaglandin responses to the inflammatory cytokine interleukin-1Î² (IL-1Î²). Here, we show that loss of the primary cilium disrupts specific molecular signalling events in cytosolic NFÎºB signalling. The induction of cyclooxygenase 2 (COX2) and inducible nitrous oxide synthase (iNOS) protein is abolished. Cells unable to assemble cilia exhibit unaffected activation of IÎºB kinase (IKK), but delayed and reduced degradation of IÎºB, due to diminished phosphorylation of inhibitor of kappa B (IÎºB) by IKK. This results in both delayed and reduced NFÎºB p65 nuclear translocation and nuclear transcript binding. We also demonstrate that heat shock protein 27 (hsp27), an established regulator of IKK, is localized to the ciliary axoneme and cellular levels are dramatically disrupted with loss of the primary cilium. These results suggest that the primary cilia compartment exerts influence over NFÎºB signalling. We propose that the cilium is a locality for regulation of the molecular events defining NFÎºB signalling events, tuning signalling as appropriate
One-loop WLWL and ZLZL scattering from the electroweak Chiral Lagrangian with a light Higgs-like scalar

By including the recently discovered Higgs-like scalar phi in the Electroweak Chiral Lagrangian, and using the Equivalence Theorem, we carry out the complete one-loop computation of the elastic scattering amplitude for the longitudinal components of the gauge bosons V = W, Z at high energy. We also compute phi phi -> phi phi and the inelastic process V V -> phi phi, and identify the counterterms needed to cancel the divergences, namely the well known a(4) and a(5) chiral parameters plus three additional ones only superficially treated in the literature because of their dimension 8. Finally we compute all the partial waves and discuss the limitations of the one-loop computation due to only approximate unitarity
Stellar population gradients in galaxy discs from the CALIFA survey

While studies of gasphase metallicity gradients in disc galaxies are common, very little has been done towards the acquisition of stellar abundance gradients in the same regions. We present here a comparative study of the stellar metallicity and age distributions in a sample of 62 nearly face-on, spiral galaxies with and without bars, using data from the CALIFA survey. We measure the slopes of the gradients and study their relation with other properties of the galaxies. We find that the mean stellar age and metallicity gradients in the disc are shallow and negative. Furthermore, when normalized to the effective radius of the disc, the slope of the stellar population gradients does not correlate with the mass or with the morphological type of the galaxies. In contrast to this, the values of both age and metallicity at similar to 2.5 scale lengths correlate with the central velocity dispersion in a similar manner to the central values of the bulges, although bulges show, on average, older ages and higher metallicities than the discs. One of the goals of the present paper is to test the theoretical prediction that non-linear coupling between the bar and the spiral arms is an efficient mechanism for producing radial migrations across significant distances within discs. The process of radial migration should flatten the stellar metallicity gradient with time and, therefore, we would expect flatter stellar metallicity gradients in barred galaxies. However, we do not find any difference in the metallicity or age gradients between galaxies with and without bars. We discuss possible scenarios that can lead to this lack of difference
Imprints of galaxy evolution on H II regions: memory of the past uncovered by the CALIFA survey

Context. H II regions in galaxies are the sites of star formation, so they are special places for understanding the build-up of stellar mass in the universe. The line ratios of this ionized gas are frequently used to characterize the ionization conditions. In particular, the oxygen abundances are assumed to trace the chemical enrichment of galaxies. Aims. We explore the connections between the ionization conditions and the properties of the overall underlying stellar population (ionizing or not-ionizing) in H II regions, in order to uncover the actual physical connection between them. Methods. We use the H II regions catalog from the CALIFA survey, which is the largest in existence with more than 5000 H II regions, to explore their distribution across the classical [O III] lambda 5007/H beta vs. [N II] lambda 6583/H alpha diagnostic diagram, and the way it depends on the oxygen abundance, ionization parameter, electron density, and dust attenuation. The location of H II regions within this diagram is compared with predictions from photoionization models. Finally, we explore the dependence of the location within the diagnostic diagram on the properties of the host galaxies, the galactocentric distances, and the properties of the underlying stellar population. Results. The H II regions with weaker ionization strengths and more metal-rich are located in the bottom righthand area of the diagram. In contrast, those regions with stronger ionization strengths and more metal poor are located in the upper lefthand end of the diagram. Photoionization models per se do not predict these correlations between the parameters and the line ratios. The H II regions located in earlier-type galaxies, closer to the center and formed in older and more metal-rich regions of the galaxies are located in the bottom-right area of the diagram. On the other hand, those regions located in late-type galaxies in the outer regions of the disks and formed on younger and more metal-poor regions lie in the top lefthand area of the diagram. The two explored line ratios show strong correlations with the age and metallicity of the underlying stellar population. Conclusions. These results indicate that although H II regions are short-lived events, they are affected by the total underlying stellar population. One may say that H II regions keep a memory of the stellar evolution and chemical enrichment that have left an imprint on both the ionizing stellar population and the ionized gas
Use of the compulsive exercise test with athletes : norms and links with rating psychopathology

This study assessed the 5-factor structure of the Compulsive Exercise Test (CET) and explored the relationship between compulsive exercise and eating psychopathology in athletes. Confirmatory and exploratory factor analyses of the CET were conducted with 689 competitive athletes (18&ndash;35 years of age). Convergent validity with the Eating Disorders Examination Questionnaire (EDE-Q) was explored. The 5-factor structure showed a poor fit; an alternative 3-factor structure is proposed. Exercising for weight control and exercising to avoid a negative mood were strongly associated with eating psychopathology. Implications for using the CET with athletes are discussed
High CD33-antigen loads in peripheral blood limit the efficacy of gemtuzumab ozogamicin (Mylotarg) treatment in acute myeloid leukemia patients

Gemtuzumab ozogamicin (Mylotarg) induces remission in approximately 30% of relapsed AML patients. We previously demonstrated that gemtuzumab infusion results in near-complete CD33 saturation in peripheral blood, and that saturating gemtuzumab levels result in continuous binding and internalization of gemtuzumab due to renewed CD33 expression. We now demonstrate that a high CD33-antigen load in peripheral blood is an independent adverse prognostic factor, likely due to peripheral consumption of gemtuzumab. Indeed, CD33 saturation in bone marrow is significantly reduced (40-90% saturation) as compared with CD33 saturation in corresponding peripheral blood samples (>90%). In vitro, such reduced CD33 saturation levels were strongly related with reduced cell kill. Apparently, high CD33-antigen loads in blood consume gemtuzumab and thereby limit its penetration into bone marrow. Consequently, CD33 saturation in bone marrow is reduced, which hampers efficient cell kill. Therefore, gemtuzumab should be administered at higher or repeated doses, or, preferably, after reduction of the leukemic cell burden by classical chemotherapy.status: publishe