545 research outputs found

    Scoping review : intergenerational resource transfer and possible enabling factors

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    We explore the intergenerational pattern of resource transfer and possible associated factors. A scoping review was conducted of quantitative, peer-reviewed, English-language studies related to intergenerational transfer or interaction. We searched AgeLine, PsycINFO, Social Work Abstracts, and Sociological Abstracts for articles published between Jane 2008 and December 2018. Seventy-five studies from 25 countries met the inclusion criteria. The scoping review categorised resource transfers into three types: financial, instrumental, and emotional support. Using an intergenerational solidarity framework, factors associated with intergenerational transfer were placed in four categories: (1) demographic factors (e.g., age, gender, marital status, education, and ethno-cultural background); (2) needs and opportunities factors, including health, financial resources, and employment status; (3) family structures, namely, family composition, family relationship, and earlier family events; and (4) cultural-contextual structures, including state policies and social norms. Those factors were connected to the direction of resource transfer between generations. Downward transfers from senior to junior generations occur more frequently than upward transfers in many developed countries. Women dominate instrumental transfers, perhaps influenced by traditional gender roles. Overall, the pattern of resource transfer between generations is shown, and the impact of social norms and social policy on intergenerational transfers is highlighted. Policymakers should recognise the complicated interplay of each factor with different cultural contexts. The findings could inform policies that strengthen intergenerational solidarity and support.</jats:p

    Are direct photons a clean signal of a thermalized quark gluon plasma?

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    Direct photon production from a quark gluon plasma (QGP) in thermal equilibrium is studied directly in real time. In contrast to the usual S-matrix calculations, the real time approach is valid for a QGP that formed and reached LTE a short time after a collision and of finite lifetime (∌10−20fm/c\sim 10-20 \mathrm{fm}/c as expected at RHIC or LHC). We point out that during such finite QGP lifetime the spectrum of emitted photons carries information on the initial state. There is an inherent ambiguity in separating the virtual from the observable photons during the transient evolution of the QGP. We propose a real time formulation to extract the photon yield which includes the initial stage of formation of the QGP parametrized by an effective time scale of formation Γ−1\Gamma^{-1}. This formulation coincides with the S-matrix approach in the infinite lifetime limit. It allows to separate the virtual cloud as well as the observable photons emitted during the pre- equilibrium stage from the yield during the QGP lifetime. We find that the lowest order contribution O(αem)\mathcal{O}(\alpha_{em}) which does \emph{not} contribute to the S-matrix approach, is of the same order of or larger than the S-matrix contribution during the lifetime of the QGP for a typical formation time ∌1fm/c\sim 1 \mathrm{fm}/c. The yield for momenta ≳3Gev/c\gtrsim 3 \mathrm{Gev}/c features a power law fall-off ∌T3Γ2/k5\sim T^3 \Gamma^2/k^{5} and is larger than that obtained with the S-matrix for momenta ≄4Gev/c\geq 4 \mathrm{Gev}/c. We provide a comprehensive numerical comparison between the real time and S-matrix yields and study the dynamics of the build-up of the photon cloud and the different contributions to the radiative energy loss. The reliability of the current estimates on photon emission is discussed.Comment: 31 pages, 12 eps figures, version to appear in PR

    Electronic structure of fluorides: general trends for ground and excited state properties

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    The electronic structure of fluorite crystals are studied by means of density functional theory within the local density approximation for the exchange correlation energy. The ground-state electronic properties, which have been calculated for the cubic structures CaF2CaF_{2},SrF2SrF_{2}, BaF2BaF_{2}, CdF2CdF_{2}, HgF2HgF_{2}, ÎČ\beta -PbF2PbF_{2}, using a plane waves expansion of the wave functions, show good comparison with existing experimental data and previous theoretical results. The electronic density of states at the gap region for all the compounds and their energy-band structure have been calculated and compared with the existing data in the literature. General trends for the ground-state parameters, the electronic energy-bands and transition energies for all the fluorides considered are given and discussed in details. Moreover, for the first time results for HgF2HgF_{2} have been presented

    Mobile inquiry-based learning with sensor-data in the school: Effects on student motivation

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    The paper discusses the design, implementation and evaluation of a pilot project that integrated inquiry-based learning with mobile game design and introduced mobile devices and sensors into classroom learningweSPOT Project - IST (FP7/2007-2013) under grant agreement N° 318499The project was supported by the SURFnet innovation grant for sustainable ICT solutions

    Nr6a1 controls Hox expression dynamics and is a master regulator of vertebrate trunk development

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    The vertebrate main-body axis is laid down during embryonic stages in an anterior-to-posterior (head-to-tail) direction, driven and supplied by posteriorly located progenitors. Whilst posterior expansion and segmentation appears broadly uniform along the axis, there is developmental and evolutionary support for at least two discrete modules controlling processes within different axial regions: a trunk and a tail module. Here, we identify Nuclear receptor subfamily 6 group A member 1 (Nr6a1) as a master regulator of trunk development in the mouse. Specifically, Nr6a1 was found to control vertebral number and segmentation of the trunk region, autonomously from other axial regions. Moreover, Nr6a1 was essential for the timely progression of Hox signatures, and neural versus mesodermal cell fate choice, within axial progenitors. Collectively, Nr6a1 has an axially-restricted role in all major cellular and tissue-level events required for vertebral column formation, supporting the view that changes in Nr6a1 levels may underlie evolutionary changes in axial formulae.Yi-Cheng Chang, Jan Manent, Jan Schroeder, Siew Fen Lisa Wong, Gabriel M. Hauswirth, Natalia A. Shylo, Emma L. Moore, Annita Achilleos, Victoria Garside, Jose M. Polo, Paul Trainor, Edwina McGlin

    Signatures of Thermal Dilepton Radiation at RHIC

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    The properties of thermal dilepton production from heavy-ion collisions in the RHIC energy regime are evaluated for invariant masses ranging from 0.5 to 3 GeV. Using an expanding thermal fireball to model the evolution through both quark-gluon and hadronic phases various features of the spectra are addressed. In the low-mass region, due to an expected large background, the focus is on possible medium modifications of the narrow resonance structures from ω\omega and ϕ\phi mesons, whereas in the intermediate-mass region the old idea of identifying QGP radiation is reiterated including effects of chemical under-saturation in the early stages of central Au+Au collisions.Comment: 17 pages ReVTeX including 16 figure

    Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths

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    We review observations of several classes of neutron-star-powered outflows: pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe interacting directly with interstellar medium (ISM), and magnetar-powered outflows. We describe radio, X-ray, and gamma-ray observations of PWNe, focusing first on integrated spectral-energy distributions (SEDs) and global spectral properties. High-resolution X-ray imaging of PWNe shows a bewildering array of morphologies, with jets, trails, and other structures. Several of the 23 so far identified magnetars show evidence for continuous or sporadic emission of material, sometimes associated with giant flares, and a few possible "magnetar-wind nebulae" have been recently identified.Comment: 61 pages, 44 figures (reduced in quality for size reasons). Published in Space Science Reviews, "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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