1,500 research outputs found
Circularly Polarized Resonant Rayleigh Scattering and Skyrmions in the = 1 Quantum Hall Ferromagnet
We use the circularly polarized resonant Rayleigh scattering (RRS) to study
the quantum Hall ferromagnet at = 1. At this filling factor we observe a
right handed copolarized RRS which probes the Skyrmion spin texture of the
electrons in the photoexcited grounds state. The resonant scattering is not
present in the left handed copolarization, and this can be related to the
correlation between Skymionic effects, screening and spin wave excitations.
These results evidence that RRS is a valid method for the study of the spin
texture of the quantum Hall states
On the variability of HD 170699 - a possible COROT target
We present the analysis of the variability of HD 170699, a COROT star showing
the characteristics of a non evolutionary Delta Scuti star with high rotational
velocity. There is a clear period of 10.45 c/d with 5.29 mmag amplitude in the
y filter. From the data, it can be seen that the star shows multi-periodicity
and it is necessary to add more frequencies to adjust the observationsComment: To appear in RevMexAA(SC) in Proceedings of XII Reunion Regional
Latinoamericana de la UAI held in Isla Margarita, Venezuela, October 22-26,
200
Plateau insulator transition in graphene
The quantum Hall effect in a single-layer graphene sample is studied in
strong magnetic fields up to 28 T. Our measurements reveal the existence of a
metal- insulator transition from filling factor to . The value
of the universal scaling exponent is found to be in graphene and
therefore in a truly two-dimensional system. This value of is in
agreement with the accepted universal value for the plateau-insulator
transitions in standard quasi two-dimensional electron and hole gases.Comment: 10 pages, 5 figure
Effects of high fat diet on salivary alpha-amylase serum parameters and food consumption in rats
Salivary a-amylase, a major protein in saliva, has been described as a marker for sympathetic
nervous system activity, hence for metabolic energy balance. In this context, its
expression in overweight and obesity is of interest. Rats fed with a diet enriched with
sunflower oil differentially gained weight yielding two subgroups according to their susceptibility
(OP) or resistance (OR) to obesity. Elevated plasmatic levels of leptin in the OP
subgroup and altered plasmatic lipid profiles (lower triglycerides and higher total choles-
terol/HDL ratio compared to controls) in OR subgroup were observed. Animals from OP
subgroup presented higher a-amylase expression and activity even prior to the dietary
treatment, suggesting that this salivary protein may constitute a putative indicator of
susceptibility for fat tissue accumulation. After 18 weeks of high-fat diet consumption,
salivary a-amylase levels did not significantly changed in OP subgroup, but increased 3-fold
in OR subgroup. The raise of a-amylase for the latter might represent an adaptation to lower
starch intake. These results suggest that salivary a-amylase secretion might be useful to
predict susceptibility for weight gain induced by high-fat diet consumption.This paper is funded by FEDER Funds through the Operational
Programme for Competitiveness Factors-COMPETE and National
Funds through FCT-Foundation for Science and Technology
under the Strategic Projects PEst-C/AGR/UI01, PEst-OE/AGR/
UI0115/2014, 15/2011, PEst-C/SAU/LA0001/2011 and PEst-C/QUI/
UI0062/2011. Authors acknowledge also the financial support
from the Portuguese Science Foundation (FCT) in the form of Post-
Doctoral grant (SFRH/BPD/63240/2009) of Elsa Lamy. The Portu-
guese Science Foundation (FCT) played no role in the develop-
ment of the present work or upon its submission for publication
Regulation of surfactant protein D in the rodent prostate
<p>Abstract</p> <p>Background</p> <p>Surfactant protein D (SP-D) is an innate immune protein that is present in mucosal lined surfaces throughout the human body, including the male reproductive tract. In the present study, we characterized the regulation of SP-D expression in the mouse and rat prostate.</p> <p>Methods</p> <p>Real time reverse transcriptase polymerase chain reaction (RT-PCR) and immunostaining were used to characterize SP-D mRNA and protein in the mouse male reproductive tract. In order to evaluate the effects of testosterone on SP-D gene expression, we measured SP-D mRNA levels via real time RT-PCR in prostates from sham-castrated mice and castrated mice. In addition, we used a rat prostatitis model in which Escherichia coli was injected into the prostate in vivo to determine if infection influences SP-D protein levels in the prostate.</p> <p>Results</p> <p>We found that SP-D mRNA and protein are present throughout the mouse male reproductive tract, including in the prostate. We determined that castration increases prostate SP-D mRNA levels (~7 fold) when compared to levels in sham-castrated animals. Finally, we demonstrated that infection in the prostate results in a significant increase in SP-D content 24 and 48 hours post-infection.</p> <p>Conclusion</p> <p>Our results suggest that infection and androgens regulate SP-D in the prostate.</p
Wildlife and Antibiotic Resistance
Antibiotic resistance is a major human health problem. While health care facilities are main contributors to the emergence, evolution and spread of antibiotic resistance, other ecosystems are involved in such dissemination. Wastewater, farm animals and pets have been considered important contributors to the development of antibiotic resistance. Herein, we review the impact of wildlife in such problem. Current evidence supports that the presence of antibiotic resistance genes and/or antibiotic resistant bacteria in wild animals is a sign of anthropic pollution more than of selection of resistance. However, once antibiotic resistance is present in the wild, wildlife can contribute to its transmission across different ecosystems. Further, the finding that antibiotic resistance genes, currently causing problems at hospitals, might spread through horizontal gene transfer among the bacteria present in the microbiomes of ubiquitous animals as cockroaches, fleas or rats, supports the possibility that these organisms might be bioreactors for the horizontal transfer of antibiotic resistance genes among human pathogens. The contribution of wildlife in the spread of antibiotic resistance among different hosts and ecosystems occurs at two levels. Firstly, in the case of non-migrating animals, the transfer will take place locally; a One Health problem. Paradigmatic examples are the above mentioned animals that cohabit with humans and can be reservoirs and vehicles for antibiotic resistance dissemination. Secondly, migrating animals, such as gulls, fishes or turtles may participate in the dissemination of antibiotic resistance across different geographic areas, even between different continents, which constitutes a Global Health issue. Copyright © 2022 Laborda, Sanz-García, Ochoa-Sánchez, Gil-Gil, Hernando-Amado and Martínez
Multi-Channel Inverse Scattering Problem on the Line: Thresholds and Bound States
We consider the multi-channel inverse scattering problem in one-dimension in
the presence of thresholds and bound states for a potential of finite support.
Utilizing the Levin representation, we derive the general Marchenko integral
equation for N-coupled channels and show that, unlike to the case of the radial
inverse scattering problem, the information on the bound state energies and
asymptotic normalization constants can be inferred from the reflection
coefficient matrix alone. Thus, given this matrix, the Marchenko inverse
scattering procedure can provide us with a unique multi-channel potential. The
relationship to supersymmetric partner potentials as well as possible
applications are discussed. The integral equation has been implemented
numerically and applied to several schematic examples showing the
characteristic features of multi-channel systems. A possible application of the
formalism to technological problems is briefly discussed.Comment: 19 pages, 5 figure
Respostas fisiológicas do pacu (piaractus mesopotamicus), tambaqui (Colossoma macropomum) e do híbrido tambacu ao aumento da concentração de NaCl.
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