1,930 research outputs found
The role of quenching time in the evolution of the mass-size relation of passive galaxies from the WISP survey
We analyze how passive galaxies at z 1.5 populate the mass-size plane
as a function of their stellar age, to understand if the observed size growth
with time can be explained with the appearance of larger quenched galaxies at
lower redshift. We use a sample of 32 passive galaxies extracted from the Wide
Field Camera 3 Infrared Spectroscopic Parallel (WISP) survey with spectroscopic
redshift 1.3 z 2.05, specific star-formation rates lower
than 0.01 Gyr, and stellar masses above 4.5 10
M. All galaxies have spectrally determined stellar ages from fitting of
their rest-frame optical spectra and photometry with stellar population models.
When dividing our sample into young (age 2.1 Gyr) and old (age 2.1
Gyr) galaxies we do not find a significant trend in the distributions of the
difference between the observed radius and the one predicted by the mass-size
relation. This result indicates that the relation between the galaxy age and
its distance from the mass-size relation, if it exists, is rather shallow, with
a slope alpha -0.6. At face value, this finding suggests that
multiple dry and/or wet minor mergers, rather than the appearance of newly
quenched galaxies, are mainly responsible for the observed time evolution of
the mass-size relation in passive galaxies.Comment: Accepted for publication in ApJ Letters; 6 pages, 3 figures, 1 tabl
Laparoscopic totally extraperitoneal inguinal hernia repair in the elderly: A prospective control study
Inguinal hernia (IH) repair can be obtained with both open and laparoscopic techniques, which are usually performed using a transabdominal preperitoneal (TAPP) or a totally extraperitoneal (TEP) approach. The aim of the study was to evaluate whether the results of laparoscopic TEP IH repair in the elderly ( 6565 years old) are different with respect to results obtained in younger patients. One hundred and four consecutive patients (four women and 100 men, median age of 57 years, range=21-85 years) with unilateral (N=21, 20.2%) or bilateral (N=83, 79.8%) IH were prospectively enrolled in the study. Patients were divided into two groups according to their age: group A (N=68, 65.4%) aged <65 years and group B (N=36, 34.6%) aged 6565 years. The mean operative time was not significantly different between groups (48\ub120 vs. 52\ub120 min, p=0.33). One case of increased PaCO2 was observed in each group (p=0.72) and two and one case of pneumoperitoneum (p=0.57) in groups A and B, respectively. Two (1.9%) patients (one in each group; p=0.55) required TEP conversion. Mild postoperative complications developed in four patients of each group (p=0.44). After one-year follow-up, three (2.9%) recurrences occurred (group 1=1, group 2=2, p=0.55), both in patients who had undergone direct IH repair. The overall postoperative relative risk of complications related to age was 1.08 (95% confidence interval=0.91-1.27, p=0.53). In conclusion, our results suggest that in patients with IH scheduled for TEP repair, age does not represent a contraindication to surgery in terms of complication rate and postoperative results
A nonequilibrium renormalization group approach to turbulent reheating
We use nonequilibrium renormalization group (RG) techniques to analyze the
thermalization process in quantum field theory, and by extension reheating
after inflation. Even if at a high scale the theory is described by a
non-dissipative theory, the RG running induces nontrivial
noise and dissipation. For long wavelength, slowly varying field
configurations, the noise and dissipation are white and ohmic, respectively.
The theory will then tend to thermalize to an effective temperature given by
the fluctuation-dissipation theorem.Comment: 8 pages, 2 figures; to appear in J. Phys. A; more detailed account of
the calculation of the noise and dissipation kernel
Mumificaçao fetal em suínos associada à toxoplasmose.
bitstream/item/58346/1/CUsersPiazzonDocuments271.pd
Análises do sêmen de suínos em centrais de inseminação artificial e detecção de circovírus suíno tipo 2 (PCV2).
bitstream/item/58128/1/CUsersPiazzonDocuments438.pd
A pricing formula for delayed claims: appreciating the past to value the future
We consider the valuation of contingent claims with delayed dynamics in a Samuelson complete
market model. We find a pricing formula that can be decomposed into terms reflecting the
current market values of the past and the future, showing how the valuation of prospective
cashflows cannot abstract away from the contribution of the past. As a practical application,
we provide an explicit expression for the market value of human capital in a setting with
wage rigidity. The formula we derive has successfully been used to explicitly solve the infinite
dimensional stochastic control problems addressed in [7], [6] and [16]
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