14,774 research outputs found
Gravitational collapse of a magnetized fermion gas with finite temperature
We examine the dynamics of a self--gravitating magnetized electron gas at
finite temperature near the collapsing singularity of a Bianchi-I spacetime.
Considering a general and appropriate and physically motivated initial
conditions, we transform Einstein--Maxwell field equations into a complete and
self--consistent dynamical system amenable for numerical work. The resulting
numerical solutions reveal the gas collapsing into both, isotropic
("point-like") and anisotropic ("cigar-like") singularities, depending on the
initial intensity of the magnetic field. We provide a thorough study of the
near collapse behavior and interplay of all relevant state and kinematic
variables: temperature, expansion scalar, shear scalar, magnetic field,
magnetization and energy density. A significant qualitative difference in the
behavior of the gas emerges in the temperature range and .Comment: 9 pages, 7 figures. arXiv admin note: substantial text overlap with
arXiv:1211.598
Glycogen Synthase Kinase 3 Inhibitors in the Next Horizon for Alzheimer's Disease Treatment
Glycogen synthase kinase 3 (GSK-3), a proline/serine protein kinase ubiquitously expressed and involved in many cellular signaling pathways, plays a key role in the pathogenesis of Alzheimer's disease (AD) being probably the link between β-amyloid and tau pathology. A great effort has recently been done in the discovery and development of different new molecules, of synthetic and natural origin, able to inhibit this enzyme, and several kinetics mechanisms of binding have been described. The small molecule called tideglusib belonging to the thiadiazolidindione family is currently on phase IIb clinical trials for AD. The potential risks and benefits of this new kind of disease modifying drugs for the future therapy of AD are discussed in this paper
Profile and reproductive roles of seminal plasma melatonin of boar ejaculates used in artificial insemination programs
Melatonin (MLT) is present in seminal plasma (SP) of mammalian species, including pigs, and it is credited with antioxidant properties. This study aims to identify the sources of variation and the role of boar SP MLT on sperm quality and functionality and in vivo fertilizing ability of liquid-stored semen doses used in AI programs. The SP MLT was measured using an ELISA kit in a total of 219 ejaculates collected from 76 boars, and reproductive records of 5,318 AI sows were recorded. Sperm quality was assessed according to motility (computer-aided sperm analysis) and viability (cytometry evaluation). Sperm functionality was assessed according to the cytometric determination of intracellular H2O2 generation, total and mitochondrial O2- production, and lipid peroxidation in liquid AI semen samples stored at 17°C over 144 h. The concentration of SP MLT differed among seasons (P < 0.01) and day length periods (P < 0.001) of the year, demonstrating that the ejaculates collected during the increasing day length period (9.80 ± 1.38 pg/mL, range: 2.75–21.94) had lower SP MLT concentrations than those collected during the decreasing day length period (16.32 ± 1.67 pg/mL, range: 5.02–35.61). The SP MLT also differed (P < 0.001) among boars, among ejaculates within boar, and among portions within the ejaculate, demonstrating that SP from the first 10 mL of sperm-rich ejaculate fraction (SRF) exhibited lower MLT concentrations than post-SRF. The SP MLT was negatively related (P < 0.001) to mitochondrial O2- production in viable sperm. The SP MLT did not differ among AI boars (n = 14) hierarchically grouped according to high and low fertility outcomes. In conclusion, SP MLT concentration in AI boars varies depending on the season of ejaculate collection and differs among boars, ejaculates within boar, and portions within ejaculate. The SP MLT may act at the mitochondrial level of sperm by reducing the generation of O2-. However, this antioxidant role of SP MLT was not reflected in sperm quality or in vivo fertility outcomes of AI semen doses
In silico discovery of a compound with nanometer affinity to antithrombin causing partial activation and increased heparin affinity
Lean Production Model Aligned with Organizational Culture to Reduce Order Fulfillment Issues in Micro- and Small-sized Textile Businesses in Peru
This paper proposes an optimization model aimed at increasing production capabilities at a small-sized textile business dedicated to manufacturing polo shirts, while reducing order fulfillment issues, including incomplete orders and late deliveries. Hence, an assessment identified downtimes from unnecessary transportation travel, time spent looking for materials, and excessive losses due to cutting fabric errors. In this light, the study focused on selecting adaptable tools, such as 5S, Plant Layout, and Method Study, which may help improve production capabilities and address these situations. However, to guarantee that the objectives set forth are being met, the organizational culture must also be identified and improved so that it may serve as the foundation for the optimization model. Then, the proposed model will be validated to determine whether the selected operating tools supported by the strengthening of organization culture contribute to increasing production
The first Frontier Fields cluster: 4.5{\mu}m excess in a z~8 galaxy candidate in Abell 2744
We present in this letter the first analysis of a z~8 galaxy candidate found
in the Hubble and Spitzer imaging data of Abell 2744, as part of the Hubble
Frontier Fields legacy program. We applied the most commonly-used methods to
select exceptionally high-z galaxies by combining non-detection and
color-criteria using seven HST bands. We used GALFIT on IRAC images for fitting
and subtracting contamination of bright nearby sources. The physical properties
have been inferred from SED-fitting using templates with and without nebular
emission. This letter is focussed on the brightest candidate we found
(m=26.2) over the 4.9 arcmin field of view covered by the WFC3.
It shows a non-detection in the ACS bands and at 3.6{\mu}m whereas it is
clearly detected at 4.5{\mu}m with rather similar depths. This break in the
IRAC data could be explained by strong [OIII]+H{\beta} lines at z~8 which
contribute to the 4.5{\mu}m photometry. The best photo-z is found at
z~8.0, although solutions at low-redshift (z~1.9) cannot be
completely excluded, but they are strongly disfavoured by the SED-fitting work.
The amplification factor is relatively small at {\mu}=1.490.02. The Star
Formation Rate in this object is ranging from 8 to 60 Mo/yr, the stellar mass
is in the order of M=(2.5-10) x 10Mo and the size is
r~0.350.15 kpc. This object is one of the first z~8 LBG candidates showing
a clear break between 3.6{\mu}m and 4.5{\mu}m which is consistent with the IRAC
properties of the first spectroscopically confirmed galaxy at a similar
redshift. Due to its brightness, the redshift of this object could potentially
be confirmed by near infrared spectroscopy with current 8-10m telescopes. The
nature of this candidate will be revealed in the coming months with the arrival
of new ACS and Spitzer data, increasing the depth at optical and near-IR
wavelengths.Comment: 4 pages, 2 figures, Accepted for publication in Astronomy and
Astrophysics Letter
Working sick and out of sorts: a cross-cultural approach on presenteeism climate, organizational justice and work–family conflict
A climate of presenteeism has important effects on employee well-being and the organization itself. Our study, based on surveys of health sector employees in six different countries (Brazil, Ecuador, Lebanon, Portugal, Russia and Spain) examines whether organizational justice plays a mediating role in the relationship between a presenteeism climate in the organization and work–family conflict (WFC). Our results indicate that the perception of organizational justice and the presenteeism climate do influence WFC. Moreover, higher levels of WFC were found in non-Latin countries. This study contributes to the work attendance and life balance field by providing cross-cultural empirical evidence corroborating the effect of justice and presenteeism climate on the WFC.info:eu-repo/semantics/acceptedVersio
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