2,048 research outputs found

    Employment Expectations and Gross Flows by Type of Work Contract

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    There is growing interest in understanding firms’ temporary and permanent employment practices and how institutional changes shape them. Using data on Spanish establishments, we examine: (a) how employers adjust temporary and permanent job and worker flows to prior employment expectations, and (b) how the 1994 and 1997 labour reforms promoting permanent employment affected establishments’ employment practices. Generally, establishments’ prior employment expectations are realized through changes in all job and worker flows. However, establishments uniquely rely on temporary hires as a buffer to confront diminishing long-run employment expectations. None of the reforms significantly affected establishments’ net temporary or permanent employment flows.http://deepblue.lib.umich.edu/bitstream/2027.42/40032/3/wp646.pd

    Spin dynamics for bosons in an optical lattice

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    We study the internal dynamics of bosonic atoms in an optical lattice. Within the regime in which the atomic crystal is a Mott insulator with one atom per well, the atoms behave as localized spins which interact according to some spin Hamiltonian. The type of Hamiltonian (Heisenberg, Ising), and the sign of interactions may be tuned by changing the properties of the optical lattice, or applying external magnetic fields. When, on the other hand, the number of atoms per lattice site is unknown, we can still use the bosons to perform general quantum computation

    A multi-wavelength view of the central kiloparsec region in the Luminous Infrared Galaxy NGC1614

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    The Luminous Infrared Galaxy NGC1614 hosts a prominent circumnuclear ring of star formation. However, the nature of the dominant emitting mechanism in its central ~100 pc is still under debate. We present sub-arcsecond angular resolution radio, mid-infrared, Pa-alpha, optical, and X-ray observations of NGC1614, aimed at studying in detail both the circumnuclear ring and the nuclear region. The 8.4 GHz continuum emission traced by the Very Large Array (VLA) and the Gemini/T-ReCS 8.7 micron emission, as well as the Pa-alpha line emission, show remarkable morphological similarities within the star-forming ring, suggesting that the underlying emission mechanisms are tightly related. We used an HST/NICMOS Pa-alpha map of similar resolution to our radio maps to disentangle the thermal free-free and non-thermal synchrotron radio emission, from which we obtained the intrinsic synchrotron power-law for each individual region within the central kpc of NGC1614. The radio ring surrounds a relatively faint, steep-spectrum source at the very center of the galaxy, suggesting that the central source is not powered by an AGN, but rather by a compact (r < 90 pc) starburst. Chandra X-ray data also show that the central kpc region is dominated by starburst activity, without requiring the existence of an AGN. We also used publicly available infrared data to model-fit the spectral energy distribution of both the starburst ring and a putative AGN in NGC1614. In summary, we conclude that there is no need to invoke an AGN to explain the observed bolometric properties of the galaxy.Comment: 13 pages, 7 figures, 5 tables. Accepted for publication in Ap

    The effect of the crisis on material deprivation in Italy and Spain

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    The focus of this paper is on the analysis of the impact of the crisis on material deprivation in two South European countries: Italy and Spain. The countries chosen have been deeply hit by the economic downturn and the use of the available comparable microdata allows us to detect the most vulnerable collective in the crisis taking into account also gender differences. The microdata used are the Italian and Spanish Income and Living Conditions Surveys of 2007 and 2010. Our results confirm the growth of deprivation as a consequence of the economic crisis in both countries and show that women are more likely to face income poverty and deprivation

    Measuring the impact of the crisis on unemployment and household income

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    The current economic crisis has significantly increased unemployment rates and its effect is more persistent than expected, leading to an increase in long term unemployment and inactivity. Among other effects, the experience of unemployment results in a decrease in purchasing power, a loss of human capital, a discouraging effect among the long-term unemployed and the inactive as well as wide-ranging social costs as a worsening of inequality and well-being indicators. The assessment of the costs of unemployment on individuals and households' living conditions is usually carried out using microeconomic data from household surveys that are however issued with delay. Hence, they do not allow for a prompt analysis of the impact of the economic cycle to guide policy makers. In the case of the European Income and Living Conditions Surveys (EU SILC) the data are available with a delay of at least one year and, additionally, we have to consider that the income data refers to the year before the survey (for instance, in the Italian case the last available microdata at the moment of writing this paper are from 2011). To solve this problem we carried out a microsimulation analysis using the European Statistics on Income and Living Conditions Surveys together with the Labour Force Survey (LFS) microdata. Therefore, we propose a methodology based on different sources of microdata that could provide the analysts and the policy makers with a more immediate analysis of the costs of unemployment. This would prove to be extremely useful in a time of high unemployment and budgetary restrictions as the one in which we find ourselves in today. The microsimulation technique developed in this paper is based on the imputation of transition probabilities and simulated income. Unlike other techniques such as the re- weighting approach, the microsimulation technique adopted here allows us to take into account the changes occurred in the composition of the unemployed. To test the validity of the proposed methodology we apply it to Italy, a European country severely hit by the crisis. We focus on the Italian economy since this country is a member of the Eurozone and its labour market has particular structural characteristics: a high degree of inflexibility in wage determination, rigidity in hiring and firing practices, very low achievement in terms of female labour-force participation and a strong duality between fixed-term and open-ended contracts. The country has an employment protection system corresponding to the Mediterranean model that is characterized by a rather low coverage of unemployment benefit moreover, the wide use of temporary contracts in hiring young workers to avoid the much higher dismissal costs of permanent contracts coupled with the deep recession, have resulted in a youth unemployment rate standing well over the European average. In Section 2 we introduce the methodology that will be used to microsimulate the effect of the crisis on income distribution and income poverty in Section 3 by relying on European surveys. In order to check its validity, we do progress with its application to Italy in Section 4. The final section will offer conclusions

    Halide and hydroxide anion binding in water

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    FTIR-ATR Spectroscopy Combined with Multivariate Regression Modeling as a Preliminary Approach for Carotenoids Determination in Cucurbita spp

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    Quantitative analysis of carotenoids has been extensively reported using UV\u2010Vis spectrophotometry and chromatography, instrumental techniques that require complex extraction protocols with organic solvents. Fourier transform infrared spectroscopy (FTIR) is a potential alternative for simplifying the analysis of food constituents. In this work, the application of FTIR with attenuated total reflectance (ATR) was evaluated for the determination of total carotenoid content (TCC) in Cucurbita spp. samples. Sixty\u2010three samples, belonging to different cultivars of butternut squash (C. moschata) and pumpkin (C. maxima), were selected and analyzed with FTIR\u2010 ATR (attenuated total reflectance). Three different preparation protocols for samples were followed: homogenization (A), freeze\u2010drying (B), and solvent extraction (C). The recorded spectra were used to develop regression models by Partial Least Squares (PLS), using data from TCC, determined by UV\u2010Vis spectrophotometry. The PLS regression model obtained with the FTIR data from the freeze\u2010dried samples, using the spectral range 920\u20133000 cm 121, had the best figures of merit (R2CAL of 0.95, R2PRED of 0.93 and RPD of 3.78), being reliable for future application in agriculture. This approach for carotenoid determination in pumpkin and squash avoids the use of organic solvents. Moreover, these results are a rationale for further exploring this technique for the assessment of specific carotenoids in food matrices

    Pervasive RNA Regulation of Metabolism Enhances the Root Colonization Ability of Nitrogen-Fixing Symbiotic &#945;-Rhizobia

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    The rhizosphere and rhizoplane are nutrient-rich but selective environments for the root microbiome. Here, we deciphered a posttranscriptional network regulated by the homologous trans-small RNAs (sRNAs) AbcR1 and AbcR2, which rewire the metabolism of the nitrogen-fixing α-rhizobium Sinorhizobium meliloti during preinfection stages of symbiosis with its legume host alfalfa. The LysR-type regulator LsrB, which transduces the cell redox state, is indispensable for AbcR1 expression in actively dividing bacteria, whereas the stress-induced transcription of AbcR2 depends on the alternative σ factor RpoH1. MS2 affinity purification coupled with RNA sequencing unveiled exceptionally large and overlapping AbcR1/2 mRNA interactomes, jointly representing ⁓6% of the S. meliloti protein-coding genes. Most mRNAs encode transport/metabolic proteins whose translation is silenced by base pairing to two distinct anti-Shine Dalgarno motifs that function independently in both sRNAs. A metabolic model-aided analysis of the targetomes predicted changes in AbcR1/2 expression driven by shifts in carbon/nitrogen sources, which were confirmed experimentally. Low AbcR1/2 levels in some defined media anticipated overexpression growth phenotypes linked to the silencing of specific mRNAs. As a proof of principle, we confirmed AbcR1/2-mediated downregulation of the l-amino acid AapQ permease. AbcR1/2 interactomes are well represented in rhizosphere-related S. meliloti transcriptomic signatures. Remarkably, a lack of AbcR1 specifically compromised the ability of S. meliloti to colonize the root rhizoplane. The AbcR1 regulon likely ranks the utilization of available substrates to optimize metabolism, thus conferring on S. meliloti an advantage for efficient rhizosphere/rhizoplane colonization. AbcR1 regulation is predicted to be conserved in related α-rhizobia, which opens unprecedented possibilities for engineering highly competitive biofertilizers

    Confirmation of a New Metal-poor Globular Cluster in the Galactic Bulge

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    © 2018. The American Astronomical Society. All rights reserved.We use deep near-IR photometry of the VISTA Variables in the V'a L'ctea (VVV) Survey and deep DECam Plane Survey (DECaPS) optical photometry to confirm the physical reality of the candidate globular cluster (GC) Minni 22, which is located in the Galactic bulge. This object, which was detected as a high density region in our maps of bulge red giants, is now confirmed as a real GC based on the optical and near-IR color'magnitude diagrams. We also recover three known fundamental mode (ab type) RR Lyrae stars within 2 arcmin of the cluster center. The presence of RR Lyrae stars also seems to confirm Minni 22 as a bonafide old and metal-poor GC. We estimate a cluster reddening E(J - Ks) = 0.6 mag and determine its heliocentric distance D = 7.4 ± 0.3 kpc. The optical and near-IR color'magnitude diagrams reveal well-defined red giant branches in all cases, including a red giant branch bump at Ks = 13.30 ± 0.05 mag. The comparison with theoretical isochrones yields a mean metallicity of [Fe/H] = -1.3 ± 0.3 dex, and age of t ∼ 11.2 Gyr. This is a good example of a new low-luminosity (MV = -6.2 mag) GC found in the central bulge of the Milky Way. After discussing the different ways to confirm the existence of bulge GC candidates, we find that one of the best methods is to use the CMDs from the combination of the DECaPS + VVV photometries.Peer reviewe
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