1,170 research outputs found

    Evidence of package trading in a mature multi-species ITQ market

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    In multi-species fisheries managed under ITQs, the existence of joint production may lead to complex catch-quota balancing issues. Previous modelling and experimental research suggest that, in such fisheries, some fishers may benefit from the ability to trade packages of fishing quotas, rather than fulfil their quota needs by simultaneously bidding on separate single-species quota markets. This note presents evidence of naturally occurring package trades in a real fishery. Based on this evidence, we suggest that further empirical and modelling research is required on the potential and limitations of package quota trading in mixed fisheries managed with ITQs. © 2014

    Induced ferromagnetism in Mn3N2 phase embedded in Mn/Si3N4 multilayers

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    Room temperature ferromagnetism has been obtained for different sets of Mn/Si3N4 multilayers prepared by sputtering. In order to find the most suitable conditions to stabilize the ferromagnetic ordering in this system, the evolution of the magnetic properties has been studied for films in which the Si3N4 layer thickness was maintained constant while that of the Mn layer was varied, Mn tm/Si3N4 3.4 nm n, and conversely, in Mn 0.7 nm/Si3N4 tsn 43 samples, in which the Mn layer thickness was kept constant while varying the Si3N4 layer thickness. Structural, compositional, electronic and magnetic characterizations have been performed by means of x-ray reflectometry, Rutherford backscattering spectrometry, x-ray photoemission spectroscopy, x-ray absorption, and superconducting quantum interference device for further knowledge of the magnetic-structural relationship in this system. Our results show that the peculiar magnetic behavior of these films is mainly related to the stabilization of a slightly distorted Mn3N2 phase that is induced by the Si3N4 at the interfaces. For samples with larger Mn layer thickness, metallic Mn and Mn3N2 phases coexist, which leads to a reduction of the total magnetization per Mn atom due to the presence of metallic Mn. For small Mn layer thickness tm 0.86 nm, where noncontinuous Mn3N2 layers are formed, the magnetization decreases noticeably due to the superparamagnetic size limit. It has been found that the best conditions for the stabilization of the ferromagnetism in this system occur when both, the manganese-rich and the silicon nitride layers, are continuous and with similar thickness, close to 3.5 nm.Ministerio de Educación y Ciencia de España-MAT2006-01004, MAT2008-06542-C04-01, MAT2008-06765-C02-02, S-0505/MAT/0194, Consolider 2010_26400 y Nanoselect CSD2007-0004

    The Recent Star Formation History of NGC 5102

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    We present Hubble Space Telescope photometry of young stars in NGC 5102, a nearby gas-rich post-starburst S0 galaxy with a bright young stellar nucleus. We use the IAC-pop/MinnIAC algorithm to derive the recent star formation history in three fields in the bulge and disk of NGC 5102. In the disk fields, the recent star formation rate has declined monotonically and is now barely detectable, but a starburst is still in progress in the bulge and has added about 2 percent to the mass of the bulge over the last 200 Myr. Other studies of star formation in NGC 5102 indicate that about 20 percent of its stellar mass was added over the past Gyr. If this is correct, then much of the stellar mass of the bulge may have formed over this period. It seems likely that this star formation was fueled by the accretion of a gas-rich system with HI mass of about 2 x 10^9 Msol which has now been almost completely converted into stars. The large mass of recently formed stars and the blue colours of the bulge suggest that the current starburst, which is now fading, may have made a significant contribution to build the bulge of NGC 5102.Comment: 36 pages, 16 figures, accepted in A

    Differential symptom weighting in estimating empirical thresholds for underlying PTSD severity: Toward a “platinum” standard for diagnosis?

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    Objective: Symptom counts as the basis for Post-Traumatic Stress Disorder (PTSD) diagnoses in the DSM presume each symptom is equally reflective of underlying disorder severity. However, the “equal weight” assumption fails to fit PTSD symptom data when tested. The present study developed an enhanced PTSD diagnosis based on (a) a conventional PTSD diagnosis from a clinical interview and (b) an empirical classification of full PTSD that reflected the relative clinical weights of each symptom. Method: Baseline structured interview data from Project Harmony (N = 2658) was used. An enhanced diagnosis for full PTSD was estimated using an empirical threshold from moderated nonlinear factor analysis (MNLFA) latent PTSD scale scores, in combination with a full conventional PTSD diagnosis based on interview data. Results: One in 4 patients in the sample had a PTSD diagnosis that was inconsistent with their empirical PTSD grouping, such that the enhanced diagnostic standard reduced the diagnostic discrepancy rate by 20%. Veterans, and in particular female Veterans, were at greatest odds for discrepancy between their underlying PTSD severity and DSM diagnosis. Conclusion: Psychometric methodologies that differentially weight symptoms can complement DSM criteria and may serve as a platform for symptom prioritization for diagnoses in future editions of DSM

    Chagas disease in Latin American migrants: a Spanish challenge

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    AbstractChagas’ disease affects millions in Latin America and is the leading cause of cardiomyopathy and death due to cardiovascular disease in patients aged 30–50 years. As a consequence of immigration it has settled in several European countries, where besides imported cases, autochthonous infections arise through vertical transmission and blood/organ donation. All Latin American immigrants who attended our Unit were screened for T. cruzi infection (ELISA and IFAT ± PCR). An ECG and echocardiogram were requested for all positive patients, and oesophageal manometry, barium swallow and barium enema were requested according to patient symptoms. All patients under 50 years without severe cardiac involvement and who had not received correct treatment previously were treated with benznidazole 5 mg/kg/day for 60 days. Patients were followed-up with serology and PCR 1 month after treatment ended and every 6 months thereafter. A total of 1146 Latin Americans were screened for T. cruzi (357 positive serology results). The typical patient profile was a Bolivian female, of rural origin, in her fourth decade of life, without evidence of visceral involvement. Treatment tolerance was poor, with 29.7% discontinuing treatment due to adverse reactions. Among those with adverse reactions (52%), the most frequent were cutaneous hypersensitivity (68.7%), gastrointestinal upset (20%) and nervous system disturbances (16.2%). T. cruzi infection is no longer limited to Latin America. Poor treatment tolerance can limit current treatment options. More epidemiological data are necessary to estimate the magnitude of a problem of great relevance for public health and health resource planning

    Interplay among critical temperature, hole content, and pressure in the cuprate superconductors

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    Within a BCS-type mean-field approach to the extended Hubbard model, a nontrivial dependence of T_c on the hole content per unit CuO_2 is recovered, in good agreement with the celebrated non-monotonic universal behaviour at normal pressure. Evaluation of T_c at higher pressures is then made possible by the introduction of an explicit dependence of the tight-binding band and of the carrier concentration on pressure P. Comparison with the known experimental data for underdoped Bi2212 allows to single out an `intrinsic' contribution to d T_c / d P from that due to the carrier concentration, and provides a remarkable estimate of the dependence of the inter-site coupling strength on the lattice scale.Comment: REVTeX 8 pages, including 5 embedded PostScript figures; other required macros included; to be published in Phys. Rev. B (vol. 54

    Moisture content modeling and effective moisture diffusivity determination during convective solar drying of blackberry (rubus spp) and basil (Ocimum basilicum L.)

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    [EN] The goal of reducing energy consumption (EC), losses and waste (FL) in the food processing is a challenges in the worldwide. The use of active solar greenhouse dryers (GHD) for EC and FL reductions has increased due to its capacity, and low operating costs. In this work the effective diffusivity (Deff) and the moisture content modeling were analized for basil (Ocimum basilicum) and blackberry pulp (Rubus rosoideae) dried in a conventional stove (CD) and an GHD coupled to an additional air solar heating system (SCHa). The loss of water and the drying rate in food materials dehydrated in the GHD is consistent with the increment or decrement of temperature during the solar day. The Deff values for basil and blackberry pulp was ranged between -1.1044x10-7 and -3.9167x10-9. The solar energy obtained in the GHD supplied the heating requirements. In general, the Page’s model was the best fit for the drying kinetics for basil and blackberry pulp.López-Ortiz, A.; Gallardo-Brígido, JC.; Silva-Norman, A.; Pilatowsky-Figueroa, I.; García-Valladares, O.; Rodríguez-Ramírez, J. (2018). Moisture content modeling and effective moisture diffusivity determination during convective solar drying of blackberry (rubus spp) and basil (Ocimum basilicum L.). En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 505-512. https://doi.org/10.4995/IDS2018.2018.7841OCS50551

    The Milky Way Bulge: Observed properties and a comparison to external galaxies

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    The Milky Way bulge offers a unique opportunity to investigate in detail the role that different processes such as dynamical instabilities, hierarchical merging, and dissipational collapse may have played in the history of the Galaxy formation and evolution based on its resolved stellar population properties. Large observation programmes and surveys of the bulge are providing for the first time a look into the global view of the Milky Way bulge that can be compared with the bulges of other galaxies, and be used as a template for detailed comparison with models. The Milky Way has been shown to have a box/peanut (B/P) bulge and recent evidence seems to suggest the presence of an additional spheroidal component. In this review we summarise the global chemical abundances, kinematics and structural properties that allow us to disentangle these multiple components and provide constraints to understand their origin. The investigation of both detailed and global properties of the bulge now provide us with the opportunity to characterise the bulge as observed in models, and to place the mixed component bulge scenario in the general context of external galaxies. When writing this review, we considered the perspectives of researchers working with the Milky Way and researchers working with external galaxies. It is an attempt to approach both communities for a fruitful exchange of ideas.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen E., Peletier R., Gadotti D., Springer Publishing. 36 pages, 10 figure

    Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider

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    Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a Δη|\Delta \eta| gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of v2{4}v_{2}\{4\} to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find v2{4}v2{6}0v_{2}\{4\} \simeq v_{2}\{6\}\neq 0 which is indicative of a Bessel-Gaussian function for the v2v_{2} distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a Δη>1.4|\Delta\eta| > 1.4 gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87

    Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

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    Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 <pT,assoc<pT,trig< < p_{\rm{T}, assoc} < p_{\rm{T}, trig} < 5.0 GeV/cc is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range η<0.9|\eta|<0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161
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