1,036 research outputs found
An Evaluation of the IIASA/VID Education-Specific Back Projections
In 2007, IIASA and the Vienna Institute of Demography of the Austrian Academy of Sciences (VID) released a database reconstructing detailed information on levels of educational attainment by age (in five-year age groups from 15 to 65+ years), sex, and for every five years between 1970 and 2000 for 120 countries (see Lutz et al. 2007). This database was created in two steps. The reconstruction methodology was applied for the first time and generated what is called the Beta version of the database (unpublished). This paper presents the validation procedure that was implemented to check the plausibility of the Beta version against scattered real data from different sources, mostly from the UNESCO collection of levels of educational attainment. The verification was done by using two main indicators where a comparison was possible: Proportion of the population with no education (E1) and proportion with a tertiary education (E4). The validation procedure was a crucial factor in arriving at the present version of the database (called version 1.0). This paper also presents the results of the validation of the published version against real data, and highlights the need for the harmonization of education data to facilitate comparison over time and space
PHARAO Laser Source Flight Model: Design and Performances
In this paper, we describe the design and the main performances of the PHARAO
laser source flight model. PHARAO is a laser cooled cesium clock specially
designed for operation in space and the laser source is one of the main
sub-systems. The flight model presented in this work is the first
remote-controlled laser system designed for spaceborne cold atom manipulation.
The main challenges arise from mechanical compatibility with space constraints,
which impose a high level of compactness, a low electric power consumption, a
wide range of operating temperature and a vacuum environment. We describe the
main functions of the laser source and give an overview of the main
technologies developed for this instrument. We present some results of the
qualification process. The characteristics of the laser source flight model,
and their impact on the clock performances, have been verified in operational
conditions.Comment: Accepted for publication in Review of Scientific Instrument
Examples of molecular switching in inorganic solids, due to temperature, light, pressure, and magnetic field
A Unified Theoretical Description of the Thermodynamical Properties of Spin Crossover with Magnetic Interactions
After the discovery of the phenomena of light-induced excited spin state
trapping (LIESST), the functional properties of metal complexes have been
studied intensively. Among them, cooperative phenomena involving low spin-high
spin (spin-crossover) transition and magnetic ordering have attracted
interests, and it has become necessary to formulate a unified description of
both phenomena. In this work, we propose a model in which they can be treated
simultaneously by extending the Wajnflasz-Pick model including a magnetic
interaction. We found that this new model is equivalent to
Blume-Emery-Griffiths (BEG) Hamiltonian with degenerate levels. This model
provides a unified description of the thermodynamic properties associated with
various types of systems, such as spin-crossover (SC) solids and Prussian blue
analogues (PBA). Here, the high spin fraction and the magnetization are the
order parameters describing the cooperative phenomena of the model. We present
several typical temperature dependences of the order parameters and we
determine the phase diagram of the system using the mean-field theory and Monte
Carlo simulations. We found that the magnetic interaction drives the SC
transition leading to re-entrant magnetic and first-order SC transitions.Comment: 30pages, 11figure
Collective effects in spin-crossover chains with exchange interaction
The collective properties of spin-crossover chains are studied.
Spin-crossover compounds contain ions with a low-spin ground state and low
lying high-spin excited states and are of interest for molecular memory
applications. Some of them naturally form one-dimensional chains. Elastic
interaction and Ising exchange interaction are taken into account. The
transfer-matrix approach is used to calculate the partition function, the
fraction of ions in the high-spin state, the magnetization, susceptibility,
etc., exactly. The high-spin-low-spin degree of freedom leads to collective
effects not present in simple spin chains. The ground-state phase diagram is
mapped out and compared to the case with Heisenberg exchange interaction. The
various phases give rise to characteristic behavior at nonzero temperatures,
including sharp crossovers between low- and high-temperature regimes. A
Curie-Weiss law for the susceptibility is derived and the paramagnetic Curie
temperature is calculated. Possible experiments to determine the exchange
coupling are discussed.Comment: 9 pages, 13 color figures, published versio
Fabrication and characterization of Eri silk fibers-based sponges for biomedical application
Cocoon-derived semi-domesticated Eri silk fibers still lack exploitation for tissue engineering applications due to their poor solubility using conventional methods. The present work explores the ability to process cocoon fibers of non-mulberry Eri silk (Samia/Philosamia ricini) into sponges through a green approach using ionic liquid (IL) â 1-buthyl-imidazolium acetate as a solvent. The formation of β-sheet structures during Eri silk/IL gelation was acquired by exposing the Eri silk/IL gels to a saturated atmosphere composed of two different solvents: (i) isopropanol/ethanol (physical stabilization) and (ii) genipin, a natural crosslinker, dissolved in ethanol (chemical crosslinking). The sponges were then obtained by freeze-drying. This approach promotes the formation of both stable and ordered non-crosslinked Eri silk fibroin matrices. Moreover, genipin-crosslinked silk fibroin sponges presenting high height recovery capacity after compression, high swelling degree and suitable mechanical properties for tissue engineering applications were produced. The incorporation of a model drug â ibuprofen â and the corresponding release study from the loaded sponges demonstrated the potential of using these matrices as effective drug delivery systems. The assessment of the biological performance of ATDC5 chondrocyte-like cells in contact with the developed sponges showed the promotion of cell adhesion and proliferation, as well as extracellular matrix production within two weeks of culture. Spongesâ intrinsic properties and biological findings open up their potential use for biomedical applications.The authors SSS, DSC, MBO, NMO acknowledge financial support
from Portuguese Foundation for Science and Technology –
FCT (Grants SFRH/BPD/45307/2008, SFRH/BPD/85790/2012,
SFRH/BD/71396/2010 and SFRH/BD/73172/2010, respectively),
‘‘Fundo Social Europeu” – FSE, and ‘‘Programa Diferencial de Potencial
Humano POPH”. This work is also financially supported by the European Union Seventh Framework Programme (FP7/2007-2013)
under grant agreement n REGPOT-CT2012-316331-POLARIS and
from Fundação para a Ciência e Tecnologia (FCT) through the project
ENIGMA – PTDC/EQU-EPR/121491/2010. The laboratory work
of SCK is supported by Department of Biotechnology and Indian
Council of Medical Research, Govt of India. SCK and RLR acknowledge
their short visits either Institutes. SCK is also grateful to 3B´ s
Research Group- Biomaterials, Biodegradables and Biomimetics,
University of Minho, Portugal for providing facilities during his
short visit
Simian Immunodeficiency Virus Infection of Chimpanzees (Pan troglodytes) Shares Features of Both Pathogenic and Non-pathogenic Lentiviral Infections.
The virus-host relationship in simian immunodeficiency virus (SIV) infected chimpanzees is thought to be different from that found in other SIV infected African primates. However, studies of captive SIVcpz infected chimpanzees are limited. Previously, the natural SIVcpz infection of one chimpanzee, and the experimental infection of six chimpanzees was reported, with limited follow-up. Here, we present a long-term study of these seven animals, with a retrospective re-examination of the early stages of infection. The only clinical signs consistent with AIDS or AIDS associated disease was thrombocytopenia in two cases, associated with the development of anti-platelet antibodies. However, compared to uninfected and HIV-1 infected animals, SIVcpz infected animals had significantly lower levels of peripheral blood CD4+ T-cells. Despite this, levels of T-cell activation in chronic infection were not significantly elevated. In addition, while plasma levels of β2 microglobulin, neopterin and soluble TNF-related apoptosis inducing ligand (sTRAIL) were elevated in acute infection, these markers returned to near-normal levels in chronic infection, reminiscent of immune activation patterns in 'natural host' species. Furthermore, plasma soluble CD14 was not elevated in chronic infection. However, examination of the secondary lymphoid environment revealed persistent changes to the lymphoid structure, including follicular hyperplasia in SIVcpz infected animals. In addition, both SIV and HIV-1 infected chimpanzees showed increased levels of deposition of collagen and increased levels of Mx1 expression in the T-cell zones of the lymph node. The outcome of SIVcpz infection of captive chimpanzees therefore shares features of both non-pathogenic and pathogenic lentivirus infections.This work was supported by the Biotechnology and Biological Sciences Research Council and by the Wellcome Trust.This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.ppat.100514
Assessing the demographic impact of migration on the working-age population across European territories
Background: Ageing is central in the European Union (EU) policy debate, with all member states being concerned about implications of growing shares of older people and declining shares of working-age populations for the sustainability of welfare and health systems. Beyond this general context, ageing patterns differ largely across EU territories because of distinctive demographic and spatial dynamics.
Objective: We study the relative contribution of cohort turnover and migration flows in shaping the demographic evolution of the working-age population at the local level.
Methods: Using Eurostat data, we decompose the changes that have occurred in the working-age population into cohort turnover and net migration effects for the 2015–2019 period, at territorial (NUTS3 and urban-intermediate-rural) levels.
Results: The majority (63%) of European (NUTS3) territories experienced negative cohort turnover effects alongside positive net migration effects during the 2015–2019 period. However, in only 27% of these territories, net migration counterbalanced the deficit in the working-age population due to cohort turnover.
Conclusions: In 2015–2019, migration was the underlying force in the evolution of the working-age population, partially compensating for the loss of population due to the cohort turnover. This effect was particularly pronounced in urban areas.
Contribution: Our contribution is twofold. First, we map EU NUTS3 territories where the working-age population is declining rapidly. Second, we give an assessment of the varied role of migration in mitigating the effect of ageing and shrinking working-age populations across EU urban, intermediate, and rural areas
Search for neutral charmless B decays at LEP
A search for rare charmless decays of \Bd and \Bs mesons has been performed in the exclusive channels \Bd_{(\mathrm s)}\ra\eta\eta, \Bd_{(\mathrm s)}\ra\eta\pio and \Bd_{(\mathrm s)}\ra\pio\pio. The data sample consisted of three million hadronic \Zo decays collected by the L3 experiment at LEP from 1991 through 1994. No candidate event has been observed and the following upper limits at 90\% confidence level on the branching ratios have been set \begin{displaymath} \mathrm{Br}(\Bd\ra\eta\eta)<4.1\times 10^{-4},\,\, \mathrm{Br}(\Bs\ra\eta\eta)<1.5\times 10^{-3},\,\, \end{displaymath} \begin{displaymath} \mathrm{Br}(\Bd\ra\eta\pio)<2.5\times 10^{-4},\,\, \mathrm{Br}(\Bs\ra\eta\pio)<1.0\times 10^{-3},\,\, \end{displaymath} \begin{displaymath} \mathrm{Br}(\Bd\ra\pio\pio)<6.0\times 10^{-5},\,\, \mathrm{Br}(\Bs\ra\pio\pio)<2.1\times 10^{-4}. \end{displaymath} These are the first experimental limits on \Bd\ra\eta\eta and on the \Bs neutral charmless modes
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