6,923 research outputs found
Observation and spectroscopy of new proton-unbound isotopes 30ar and 29cl: an interplay of prompt two-proton and sequential decay
Previously unknown isotopes 30Ar and 29Cl have been identified by measurement of the trajectories of their in-flight decay products 28S+p+p and 28S+p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and the structure of the parent states. The ground states of 30Ar and 29Cl were found at 2.25+0.15−0.10 and 1.8±0.1 MeV above the two- and one-proton thresholds, respectively. The lowest states in 30Ar and 29Cl point to a violation of isobaric symmetry in the structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the 30Ar ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. The first hint of a fine structure of the two-proton decay of 30Ar∗(2+) has been obtained by detecting two decay branches into the ground and first-excited states of the 28S fragment.Polish National Science Center UMO-2011/01/B/ST2/0194
An L0 dwarf companion in the brown dwarf desert, at 30 AU
We present the discovery of an L0 companion to the nearby M1.5 dwarf G
239-25, at a projected distance of 31 AU. It is the faintest companion
discovered so far in our adaptive optics survey of all known M dwarfs within 12
pc, and it lies at the stellar/substellar limit. Given the assumed age of the
primary star, the companion is likely an extremely low mass star. The long
orbital period of G 239-25 AB ( years) precludes a direct mass
determination, but the relatively wide angular separation will allow detailed
analyses of its near infrared and visible spectra.Comment: accepted by AA Letter
A high-entropy manganite in an ordered nanocomposite for long-term application in solid oxide cells.
The implementation of nano-engineered composite oxides opens up the way towards the development of a novel class of functional materials with enhanced electrochemical properties. Here we report on the realization of vertically aligned nanocomposites of lanthanum strontium manganite and doped ceria with straight applicability as functional layers in high-temperature energy conversion devices. By a detailed analysis using complementary state-of-the-art techniques, which include atom-probe tomography combined with oxygen isotopic exchange, we assess the local structural and electrochemical functionalities and we allow direct observation of local fast oxygen diffusion pathways. The resulting ordered mesostructure, which is characterized by a coherent, dense array of vertical interfaces, shows high electrochemically activity and suppressed dopant segregation. The latter is ascribed to spontaneous cationic intermixing enabling lattice stabilization, according to density functional theory calculations. This work highlights the relevance of local disorder and long-range arrangements for functional oxides nano-engineering and introduces an advanced method for the local analysis of mass transport phenomena
Strangeness, Charm and Beauty in Quark Matter: SQM 2007 Experimental Overview
This paper aims at providing an experimental overview of the Strangeness in
Quark Matter 2007 ConferenceComment: Proceedings of Strangeness in Quark Matter 2007, submitted to Journal
of Physics
Tevatron-for-LHC Report: Preparations for Discoveries
This is the "TeV4LHC" report of the "Physics Landscapes" Working Group,
focused on facilitating the start-up of physics explorations at the LHC by
using the experience gained at the Tevatron. We present experimental and
theoretical results that can be employed to probe various scenarios for physics
beyond the Standard Model.Comment: 222 pp., additional contribution added, typos/layout correcte
Emission Features and Source Counts of Galaxies in Mid-Infrared
In this work we incorporate the newest ISO results on the mid-infrared
spectral-energy-distributions (MIR SEDs) of galaxies into models for the number
counts and redshift distributions of MIR surveys. A three-component model, with
empirically determined MIR SED templates of (1) a cirrus/PDR component (2) a
starburst component and (3) an AGN component, is developed for infrared
(3--120\micron) SEDs of galaxies. The model includes a complete IRAS 25\micron
selected sample of 1406 local galaxies (; Shupe et al. 1998a).
Results based on these 1406 spectra show that the MIR emission features cause
significant effects on the redshift dependence of the K-corrections for fluxes
in the WIRE 25\micron band and ISOCAM 15\micron band. This in turn will affect
deep counts and redshift distributions in these two bands, as shown by the
predictions of two evolution models (a luminosity evolution model with
and a density evolution model with ).
The dips-and-bumps on curves of MIR number counts, caused by the emission
features, should be useful indicators of evolution mode. The strong emission
features at --8\micron will help the detections of relatively high
redshift () galaxies in MIR surveys. On the other hand, determinations
of the evolutionary rate based on the slope of source counts, and studies on
the large scale structures using the redshift distribution of MIR sources, will
have to treat the effects of the MIR emission features carefully. We have also
estimated a 15\micron local luminosity function from the predicted 15\micron
fluxes of the 1406 galaxies using the bivariate (15\micron vs. 25\micron
luminosities) method. This luminosity function will improve our understanding
of the ISOCAM 15\micron surveys.Comment: 24 pages, 14 EPS figures. Accepted by Ap
Precision measurements of the top quark mass from the Tevatron in the pre-LHC era
The top quark is the heaviest of the six quarks of the Standard Model.
Precise knowledge of its mass is important for imposing constraints on a number
of physics processes, including interactions of the as yet unobserved Higgs
boson. The Higgs boson is the only missing particle of the Standard Model,
central to the electroweak symmetry breaking mechanism and generation of
particle masses. In this Review, experimental measurements of the top quark
mass accomplished at the Tevatron, a proton-antiproton collider located at the
Fermi National Accelerator Laboratory, are described. Topologies of top quark
events and methods used to separate signal events from background sources are
discussed. Data analysis techniques used to extract information about the top
mass value are reviewed. The combination of several most precise measurements
performed with the two Tevatron particle detectors, CDF and \D0, yields a value
of \Mt = 173.2 \pm 0.9 GeV/.Comment: This version contains the most up-to-date top quark mass averag
Worker remittances and the global preconditions of ‘smart development’
With the growing environmental crisis affecting our globe, ideas to weigh economic or social progress by the ‘energy input’ necessary to achieve it are increasingly gaining acceptance. This question is intriguing and is being dealt with by a growing number of studies, focusing on the environmental price of human progress. Even more intriguing, however, is the question of which factors of social organization contribute to a responsible use of the resources of our planet to achieve a given social result (‘smart development’). In this essay, we present the first systematic study on how migration – or rather, more concretely, received worker remittances per GDP – helps the nations of our globe to enjoy social and economic progress at a relatively small environmental price. We look at the effects of migration on the balance sheets of societal accounting, based on the ‘ecological price’ of the combined performance of democracy, economic growth, gender equality, human development, research and development, and social cohesion. Feminism in power, economic freedom, population density, the UNDP education index as well as the receipt of worker remittances all significantly contribute towards a ‘smart overall development’, while high military expenditures and a high world economic openness are a bottleneck for ‘smart overall development’
Comparative analysis of systemic oncological treatments and best supportive care for advanced gastresophageal cancer : A comprehensive scoping review and evidence map
Altres ajuts: acords transformatius de la UABTo identify, describe, and organize the available evidence regarding systemic oncological treatments compared to best supportive care (BSC) for advanced gastresophageal cancer. We conducted a thorough search across MEDLINE (PubMed), EMbase (Ovid), The Cochrane Library, Epistemonikos, PROSPERO, and Clinicaltrials.gov. Our inclusion criteria encompassed systematic reviews, randomized controlled trials, quasi-experimental and observational studies involving patients with advanced esophageal or gastric cancer receiving chemotherapy, immunotherapy or biological/targeted therapy compared to BSC. The outcomes included survival, quality of life, functional status, toxicity, and quality of end-of-life care. We included and mapped 72 studies, comprising SRs, experimental and observational designs, 12 on esophageal cancer, 51 on gastric cancer, and 10 both locations. Most compared schemes including chemotherapy (47 studies), but did not report therapeutic lines. Moreover, BSC as a control arm was poorly defined, including integral support and placebo. Data favor the use of systemic oncological treatments in survival outcomes and BSC in toxicity. Data for outcomes including quality of life, functional status, and quality of end-of-life care were limited. We found sundry evidence gaps specifically in assessing new treatments such as immunotherapy and important outcomes such as functional status, symptoms control, hospital admissions, and the quality of end-life care for all the treatments. There are important evidence gaps regarding new for patients with advanced gastresophageal cancer and the effect of systemic oncological treatments on important patient-centered outcomes beyond survival. Future research should clearly describe the population included, specifying previous treatments and considering therapeutic, and consider all patient-centered outcomes. Otherwise, it will be complex to apply research results into practice
The DIRTY Model II: Self-Consistent Treatment of Dust Heating and Emission in a 3-D Radiative Transfer Code
In this paper and a companion paper we present the DIRTY model, a Monte Carlo
radiative transfer code, self-consistently including dust heating and emission,
and accounting for the effects of the transient heating of small grains. The
code is completely general; the density structure of the dust, the number and
type of heating sources, and their geometric configurations can be specified
arbitrarily within the model space. Source photons are tracked through the
scattering and absorbing medium using Monte Carlo techniques and the effects of
multiple scattering are included. The dust scattering, absorbing, and emitting
properties are calculated from realistic dust models derived by fitting
observed extinction curves in Local Group galaxies including the Magellanic
Clouds and the Milky Way. The dust temperature and the emitted dust spectrum
are calculated self consistently from the absorbed energy including the effects
of temperature fluctuations in small grains. Dust self-absorption is also
accounted for, allowing the treatment of high optical depths, by treating
photons emitted by the dust as an additional heating source and adopting an
iterative radiative transfer scheme. As an illustrative case, we apply the
DIRTY radiative transfer code to starburst galaxies wherein the heating sources
are derived from stellar evolutionary synthesis models. Within the context of
the starburst model, we examine the dependence of the UV to FIR SED, dust
temperatures, and dust masses predicted by DIRTY on variations of the input
parameters.Comment: 23 pages (emulateapj, single column), 17 figures. To appear in the
ApJ, in pres
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