94 research outputs found
Evidence for a Photospheric Component in the Prompt Emission of the Short GRB120323A and its Effects on the GRB Hardness-Luminosity Relation
The short GRB 120323A had the highest flux ever detected with the Fermi/GBM.
Here we study its remarkable spectral properties and their evolution using two
spectral models: (i) a single emission component scenario, where the spectrum
is modeled by the empirical Band function, and (ii) a two component scenario,
where thermal (Planck-like) emission is observed simultaneously with a
non-thermal component (a Band function). We find that the latter model fits the
integrated burst spectrum significantly better than the former, and that their
respective spectral parameters are dramatically different: when fit with a Band
function only, the Epeak of the event is unusually soft for a short GRB, while
adding a thermal component leads to more typical short GRB values. Our
time-resolved spectral analysis produces similar results. We argue here that
the two-component model is the preferred interpretation for GRB 120323A, based
on: (i) the values and evolution of the Band function parameters of the two
component scenario, which are more typical for a short GRB, and (ii) the
appearance in the data of a significant hardness-intensity correlation,
commonly found in GRBs, when we employee two-component model fits; the
correlation is non-existent in the Band-only fits. GRB 110721A, a long burst
with an intense photospheric emission, exhibits the exact same behavior. We
conclude that GRB 120323A has a strong photospheric emission contribution,
first time observed in a short GRB. Magnetic dissipation models are difficult
to reconcile with these results, which instead favor photospheric thermal
emission and fast cooling synchrotron radiation from internal shocks. Finally,
we derive a possibly universal hardness-luminosity relation in the source frame
using a larger set of GRBs L,i=(1.59+/-0.84).10^50 (Epeak,i)^(1.33+/-0.07)
erg/s), which could be used as a possible redshift estimator for cosmology.Comment: 27 pages, 13 figures, Accepted by ApJ (April, 7th 2013
Domain walls in light of Cosmic Microwave Background and Pulsar Timing Array data
In this paper, we study the compatibility of biased domain wall scenarios
with current gravitational wave data. We show that the Cosmic Microwave
Background bounds on the fractional density of gravitational waves at the time
of decoupling may only slightly improve on the constraints that result from
requiring that domain walls never dominate the cosmic energy budget. We show
that, despite this, the range of energy scales of the domain-wall forming phase
transitions are already quite constricted, even if the networks decay early in
cosmological history. We also show that, if domain walls are to provide an
explanation to the stochastic gravitational wave background that was recently
detected by pulsar timing arrays, they not only have to decay early in the
radiation dominated era but also their energy density would have to be close to
dominating the energy density of the universe, which would require some fine
tuning of the parameters of the models
Determination of nutrient salts by automatic methods both in seawater and brackish water: the phosphate blank
9 páginas, 2 tablas, 2 figurasThe main inconvenience in determining nutrients in seawater by automatic methods is simply solved:
the preparation of a suitable blank which corrects the effect of the refractive index change on the recorded
signal. Two procedures are proposed, one physical (a simple equation to estimate the effect) and the other
chemical (removal of the dissolved phosphorus with ferric hydroxide).Support for this work came from CICYT (MAR88-0245 project) and
Conselleria de Pesca de la Xunta de GaliciaPeer reviewe
Inborn errors of immunity: Manifestation, treatment, and outcome—an ESID registry 1994–2024 report on 30,628 patients
The European Society for Immunodeficiencies patient registry (ESID-R), established in 1994, is one of the world’s largest databases on inborn errors of immunity (IEI). IEI are genetic disorders predisposing patients to infections, autoimmunity, inflammation, allergies, and malignancies. Treatments include antimicrobial therapy, immunoglobulin replacement, immune modulation, stem cell transplantation, and gene therapy. Data from 194 centers in 33 countries capture clinical manifestations and treatments from birth onward, with annually expected updates. This report reviews the ESID-R’s structure, data content, and impact. The registry includes 30,628 patient datasets (aged 0–97.9 years; median follow-up: 7.2 years; total 825,568.2 patient-years), with 13,550 cases in 15 sub-studies. It has produced 84 peer-reviewed publications (mean citation rate: 95). Findings include real-world observations of IEI diagnoses, genetic causes, clinical manifestations, treatments, and survival trends. The ESID-R fosters global collaboration, advancing IEI research and patient care. This report highlights the key role of the multinational ESID-R, led by an independent medical society, in evidence-based discovery
Vorteile der On-Line-Erfassung von Daten für Qualitätssicherung und Leistungserfassung innerhalb eines EDV-Programmes
Domain walls in light of Cosmic Microwave Background and Pulsar Timing Array data
International audienceIn this paper, we study the compatibility of biased domain wall scenarios with current gravitational wave data. We show that the Cosmic Microwave Background bounds on the fractional density of gravitational waves at the time of decoupling may only slightly improve on the constraints that result from requiring that domain walls never dominate the cosmic energy budget. We show that, despite this, the range of energy scales of the domain-wall forming phase transitions are already quite constricted, even if the networks decay early in cosmological history. We also show that, if domain walls are to provide an explanation to the stochastic gravitational wave background that was recently detected by pulsar timing arrays, they not only have to decay early in the radiation dominated era but also their energy density would have to be close to dominating the energy density of the universe, which would require some fine tuning of the parameters of the models
Stochastic gravitational wave background generated by domain wall networks
In this work we study the power spectrum of the Stochastic Gravitational Wave
Background produced by standard and biased domain wall networks, using the
Velocity-dependent One-Scale model to compute the cosmological evolution of
their characteristic scale and root-mean-squared velocity. We consider a
standard radiation + background and assume that a constant
fraction of the energy of collapsing domain walls is emitted in the form of
gravitational waves. We show that, in an expanding background, the total energy
density in gravitational radiation decreases with cosmic time (after a short
initial period of quick growth). We also propose a two parameter model for the
scale-dependence of the frequency distribution of the gravitational waves
emitted by collapsing domain walls. We determine the corresponding power
spectrum of the Stochastic Gravitational Wave Background generated by domain
walls, showing that it is a monotonic decreasing function of the frequency for
frequencies larger than that of the peak generated by the walls that have
decayed most recently. We also develop an analytical approximation to this
spectrum, assuming perfect linear scaling during both the radiation and matter
eras, in order to characterize the dependence of the amplitude, peak frequency
and slope of the power spectrum on the model parameters
Early atopic disease and early childhood immunization - is there a link?
Background: There are frequent concerns about early immunizations among the parents of children at heightened risk for atopy. The study assessed the effect of vaccine immunization before the first birthday on eczema severity and allergic sensitization in the second year of life
Medizin und die Internationale Raumstation: Schrittmacher für irdische Telemedizin-Anwendungen
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