We report the large effort that is producing comprehensive high-level young star cluster (YSC) catalogs for a significant fraction of galaxies observed with the Legacy ExtraGalactic UV Survey (LEGUS) ...Hubble treasury program. We present the methodology developed to extract cluster positions, verify their genuine nature, produce multiband photometry (from NUV to NIR), and derive their physical properties via spectral energy distribution fitting analyses. We use the nearby spiral galaxy NGC 628 as a test case for demonstrating the impact that LEGUS will have on our understanding of the formation and evolution of YSCs and compact stellar associations within their host galaxy. Our analysis of the cluster luminosity function from the UV to the NIR finds a steepening at the bright end and at all wavelengths suggesting a dearth of luminous clusters. The cluster mass function of NGC 628 is consistent with a power-law distribution of slopes and a truncation of a few times 105 . After their formation, YSCs and compact associations follow different evolutionary paths. YSCs survive for a longer time frame, confirming their being potentially bound systems. Associations disappear on timescales comparable to hierarchically organized star-forming regions, suggesting that they are expanding systems. We find mass-independent cluster disruption in the inner region of NGC 628, while in the outer part of the galaxy there is little or no disruption. We observe faster disruption rates for low mass (≤104 ) clusters, suggesting that a mass-dependent component is necessary to fully describe the YSC disruption process in NGC 628.
ABSTRACT The nearby dwarf starburst galaxy NGC 5253 hosts a number of young, massive star clusters, the two youngest of which are centrally concentrated and surrounded by thermal radio emission (the ..."radio nebula"). To investigate the role of these clusters in the starburst energetics, we combine new and archival Hubble Space Telescope images of NGC 5253 with wavelength coverage from 1500 to 1.9 m in 13 filters. These include H , Pβ, and P , and the imaging from the Hubble Treasury Program LEGUS (Legacy Extragalactic UV Survey). The extraordinarily well-sampled spectral energy distributions enable modeling with unprecedented accuracy the ages, masses, and extinctions of the nine optically brightest clusters (MV < −8.8) and the two young radio nebula clusters. The clusters have ages ∼1-15 Myr and masses ∼1 × 104-2.5 × 105 M . The clusters' spatial location and ages indicate that star formation has become more concentrated toward the radio nebula over the last ∼15 Myr. The most massive cluster is in the radio nebula; with a mass ∼2.5 × 105 M and an age ∼1 Myr, it is 2-4 times less massive and younger than previously estimated. It is within a dust cloud with AV ∼ 50 mag, and shows a clear near-IR excess, likely from hot dust. The second radio nebula cluster is also ∼1 Myr old, confirming the extreme youth of the starburst region. These two clusters account for about half of the ionizing photon rate in the radio nebula, and will eventually supply about 2/3 of the mechanical energy in present-day shocks. Additional sources are required to supply the remaining ionizing radiation, and may include very massive stars.
Although not assumed explicitly, we show that neutrality plays an important role in Arrow and other impossibility theorems. Applying it to pivotal voters we produce direct proofs of classical ...impossibility theorems, including Arrow's, as well as extend some of these theorems. We further explore the role of neutrality showing that it is equivalent to Pareto or reverse Pareto, and to effective dictatorship for non-null social welfare functions satisfying the principle of independence of irrelevant alternatives. It is also equivalent to Wilson's Citizens' Sovereignty-which is related to the intuition that symmetry over alternatives makes social preference depend only on citizens' preferences. We show that some of these results are more fundamental than others in that they extend both to infinite societies and to considerably smaller domains of preferences. Finally, as an application of Arrow's theorem, we provide a simple proof of the Gibbard-Satterthwaite theorem.
We introduce a simple model of oligopolistic competition where firms first build capacity, and then, after observing the capacity decisions, choose a reservation price at which they are willing to ...supply their capacities. This model describes many markets more realistically than the model of Kreps and Scheinkman Kreps, D., Scheinkman, J., 1983. Quantity precommitment and Bertrand competition yield Cournot outcomes. Bell J. Econ. 14, 326–337. We show that in this new model every pure strategy equilibrium yields the Cournot outcome, and that the Cournot outcome can be sustained by a pure strategy subgame perfect equilibrium.
The objective of the study was to evaluate the quality of the health care to the epileptic patient in Spain including recently diagnosed patients, controlled patients and medically refractory ...patients.
Throughout years 2001-2002 a questionnaire of consensus was agreed by neurologists from surgical epilepsy units, epilepsy units, community hospitals and outpatient clinics.
A total of 139 questionnaires were analysed. Only one third of the hospitals had a specialized epilepsy clinic. The longest waiting lists for diagnostic procedures were video EEG and Holter EEG, with 175 and 97.6 days, respectively. Clear differences between autonomous communities as far as availability of neurologists on duty, availability of diagnostic tests and number of epilepsy units are stated, existing, in general, more resources in the autonomous communities with health transferred before 2002 and Madrid.
As much the lack of resources as the inequalities indicate that we are still far from the quality standards recommended by the International League Against Epilepsy (ILAE), lacking a suitable lanning that eliminates the inequalities and it so approaches us a system of assistance integrated in different levels as it is set out by the international scientific community.
Previous epidemiologic studies have shown that around 5% of the population will suffer a tonic clonic seizure during their life. The aim of this study is to know how many and which of these people ...will suffer a second seizure and become epileptic.
175 patients seen in the emergency department of the Vall d Hebron Hospital were included. They were divided in three groups according to the clinical suspicion of having had a seizure. Only the patients with low clinical suspicion and also normal EEG standard and EEG in sleep deprivation were excluded (16). The patients with previous episodes of lost of consciousness, previous episodes of possible mioclonias or absence were not excluded.
After a first tonic clonic seizure the patients who did not receive treatment present a risk of relapse of 66% followed two years and the patients treated 46%. The difference between two groups was statistically significant. Dividing the patients according to the type of seizure: primary generalised, partial or nor localised we did not find differences in the risk of relapse. Dividing the patients according to their etiology we found that the group of patients with provoked seizures was different from the rest groups: symptomatic, genetic or cryptogenic and idiopathic, who had equal risk of recurrence. We found that the presence of previous episodes of lost of consciousness, the clinical suspicion and, probably (we obtained nearly statistical signification) de EEG and the presence of previous mioclonias or absences were risk factors. Other factor like age at the moment of the first episode, febrile seizures, familiar history, antecedents of stroke, encephalitis, neurosurgery and dementia were not related with the risk of relapse.
With the exception of provoked seizures the rest of first tonic clonic seizures have a high risk of relapse (around 60 70%) and if they go with abnormal EEG, previous episodes of absences or mioclonias starting treatment must be considered.
We develop a model of double matching in the labor market and the social environment in order to explain different migration patterns in response to local economic shocks. This approach explains the ...different behaviors of workers in different groups, regions, or countries in an endogenous way by showing the existence of multiple equilibria, rather than in an exogenous manner by introducing ex ante regulations or unemployment benefits. This model can also explain why individuals from some communities form ‘sister’ communities in some cases and not in others.
The ultra-luminous infrared galaxy Arp2 20 is a late-stage merger with several tidal structures in the outskirts and two very compact, dusty nuclei that show evidence for extreme star formation and ...host at least one AGN. New and archival high-resolution images taken by the Hubble Space Telescope provide a state-of-the-art view of the structures, dust, and stellar clusters in Arp 220. We find that ~90% of the Halpha emission arises from a shock-ionized bubble emanating from the AGN in the western nucleus, while the nuclear disks dominate the Pbeta emission. Four very young (~3-6 Myr) but lower mass (< 10^4 Msun) clusters are detected in Halpha within a few arcsec of the nuclei, but produce less than 1% of the line emission. We see little evidence for a population of massive clusters younger than 100Myr anywhere in Arp 220. From the masses and ages of the detected clusters, we find that star formation took place more-or-less continuously starting ~few Gyr ago with a rate between ~3-12 Msun/yr. Approximately 100Myr ago, star formation shut off suddenly everywhere, except in the nuclear disks. A very recent flicker of weak star formation produced the four young, low-mass clusters, while the rest of the galaxy appears to have remained in a post-starburst state. Cluster ages indicate that the tidal structures on the west side of the galaxy are older than those on the east side, but all appear to pre-date the shutoff of star formation. Arp 220 has many of the characteristics expected of a 'Shocked Post-Starburst Galaxy' or SPOG, since most of the system has been in a post-starburst state for the past ~100Myr and the detected Halpha emission arises from shocked rather than photo-ionized gas.
Different issues associated to post-cervical artificial insemination (PCAI) in sows such as bleeding, suppuration, or semen backflow and their impact on the farm reproductive parameters were ...evaluated. PCAI of 1991 Large White × Landrace multiparous sows were realised in a commercial pig farm in Tauste (Zaragoza, Spain). The parameters studied were: the cycle of the sow (parity); need to perform three or more inseminations per cycle; presence of bleeding or suppurations after insemination, semen backflow; abortions; farrowing rate; returns on heat, total alive, dead and weaned piglets per litter. The results showed that the cycle of the sow was significantly associated with the need to perform three or more inseminations per cycle, a lower farrowing rate, more abortions, lower number of total, alive and weaned born piglets per litter. Furthermore, bleeding was related to a lower total and alive born piglets per litter as well as to the sow cycle number.
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