On attributes of a Rotating Neutron star with a Hyperon core

We study the effect of rotation on global properties of neutron star with a hyperon core in an effective chiral model with varying nucleon effective mass within a mean field approach. The resulting gross properties of the rotating compact star sequences are then compared and analyzed with other theoretical predictions and observations from neutron stars. The maximum mass of the compact star predicted by the model lies in the range $(1.4-2.4) ~M_{\odot}$ at Kepler frequency $\Omega_K$, which is consistant with recent observation of high mass stars thereby reflecting the sensitivity of the underlying nucleon effective mass in the dense matter EoS. We also discuss the implications of the experimental constraints from the flow data from heavy-ion collisions on the global properties of the rotating neutron stars.Comment: 11 Pages, 10 Figures and 2 Table

PREPARATION, IDENTIFICATION AND BIOLOGICAL PROPERTIES OF NEW FLUORIDE NANOCOMPOUNDS

Indexación: Web of Science; Scopus.Nanoparticles (NPs) of new fluoride (SrF2 and MgF2) nanocompounds were synthesized by the simple chemical method of precipitation in ethanol. Synthesis of the strontium fluoride (SrF2)-magnesium oxide (MgO) nanocomposite was achieved through the ultrasonic method. These prepared nanopowders were characterized through Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, Powder X-ray Diffraction (PXRD) and Scanning Electron Microscopy (SEM). FT-IR confirmed the purity of the synthesized fluoride NPs by evaluation of the vibrations, and UV-Visible showed the intense absorption peaks of NPs. PXRD analysis indicated the average of particle size, and SEM demonstrated a nearly spherical morphology of the NPs. The antibacterical properties of the nanopowders on Staphylococcus Aureus, Bacillus Subtilis and E. Aklay bacteria were studied, with the strongest effect by the magnesium fluoride (MgF2) NPs and the SrF2-MgO nanocomposite.http://ref.scielo.org/yfr3f

Higher dimensional gravity invariant under the Poincare group

It is shown that the Stelle-West Grignani-Nardelli-formalism allows, both when odd dimensions and when even dimensions are considered, constructing actions for higher dimensional gravity invariant under local Lorentz rotations and under local Poincar\`{e} translations. It is also proved that such actions have the same coefficients as those obtained by Troncoso and Zanelli in ref. Class. Quantum Grav. 17 (2000) 4451.Comment: 7 pages, Latex, accepted in Phys. Rev.

Supergravity with cosmological constant and the AdS group

It is shown that the supersymmetric extension of the Stelle-West formalism permits the construction of an action for $(3+1)$-dimensional N=1 supergravity with cosmological constant genuinely invariant under the $OSp(4/1).$ Since the action is invariant under the supersymmetric extension of the $AdS$ group, the supersymmetry algebra closes off shell without the need for auxiliary fields. The limit case $m\to 0$, i.e.$(3+1)$ -dimensional N=1 supergravity invariant under the Poincar\'{e} supergroup is also discussed.Comment: 10 page

Perturbative approach to the structure of rapidly rotating neutron stars

We construct models of rotating stars using the perturbative approach introduced by J. Hartle in 1967, and a set of equations of state proposed to model hadronic interactions in the inner core of neutron stars. We integrate the equations of stellar structure to third order in the angular velocity and show, comparing our results to those obtained with fully non linear codes, to what extent third order corrections are needed to accurately reproduce the moment of inertia of a star which rotates at rates comparable to that of the fastest isolated pulsars.Comment: 17 pages, 5 figures, minor changes to match version accepted by Phys. Rev.

Glial-derived neurotrophic factor modulates enteric neuronal survival and proliferation through neuropeptide Y.

BACKGROUND & AIMS: Glial-derived neurotrophic factor (GDNF) promotes the survival and proliferation of enteric neurons. Neuropeptide Y (NPY) is an important peptide regulating gastrointestinal motility. The role of NPY on the survival and proliferation of enteric neurons is not known. We examined the effects of GDNF on the expression and release of NPY from enteric neurons and the role of NPY in promoting enteric neuronal proliferation and survival. METHODS: Studies were performed in primary enteric neuronal cultures and NPY knockout mice (NPY(-/-)). GDNF-induced expression of NPY was assessed by reverse-transcription polymerase chain reaction (RT-PCR), immunocytochemistry, and enzyme-linked immunosorbent assay. Using NPY-siRNA and NPY-Y1 receptor antagonist, we examined the role of NPY in mediating the survival and proliferation effects of GDNF. Gastrointestinal motility was assessed by measuring gastric emptying, intestinal transit, and isometric muscle recording from intestinal muscle strips. RESULTS: GDNF induced a significant increase in NPY messenger RNA and protein expression in primary enteric neurons and the release of NPY into the culture medium. NPY (1 mumol/L) significantly increased proliferation of neurons and reduced apoptosis. In the presence of NPY-siRNA and NPY-Y1 receptor antagonist or in enteric neurons cultured from NPY(-/-) mice, GDNF-mediated neuronal proliferation and survival was reduced. NPY increased the phosphorylation of Akt, a downstream target of the PI-3-kinase pathway. In NPY(-/-) mice, there were significantly fewer nNOS-containing enteric neurons compared with wild-type (WT) mice. NPY(-/-) mice had accelerated gastric emptying and delayed intestinal transit compared with WT mice. CONCLUSIONS: We demonstrate that NPY acts as an autocrine neurotrophic factor for enteric neurons

Comparison between damage detection methods applied to beam structures

Damage detection methods based on the dynamic measurements of structures are one of the most important techniques for damage evaluation in bridges. The methods considered in this study have been recognized as the most promising tools for damage detection in these structures. Some of these methods were applied during the deliberate damage of Z24 Bridge in Switzerland and I-24 Bridge in USA. These methods have been evaluated in different cases and therefore it is difficult to decide which method is the best for the particular purpose. The comparison of these methods will be done using simulations performed in a composite simply supported bridge. Almost all the methods provided good results when noise was not taken into account. However, accuracy of these methods is still limited when noise is present during acquisition of the dynamic response.(undefined

Using novel palaeolimnological techniques to define conservation objectives for Hatch Mere: Report for Cheshire Wildlife Trust

This is the final report to Natural England on the project ‘Using novel palaeolimnological techniques to define lake conservation objectives for Hatch Mere’. The aim is to use existing and recently developed palaeoecological techniques to define reference conditions and assess the condition of Hatch Mere Special Scientific Interest (SSSIs) in the Cheshire meres, and thereby assist in the setting of conservation objectives and management goals. Two sediment cores (one open water and one marginal), approximately 1 m in length, were collected from Hatch Mere in August 2011. The cores were sampled at 1 cm intervals throughout and approximately ten samples from each site were analysed for diatoms, Cladocera, macrofossils, geochemistry (XRF) and pigments. The cores were dated using radiometric techniques in order to place the fossil remains within a known time frame. An existing diatom-total phosphorus (TP) transfer function was applied to the diatom data to reconstruct the nutrient history of the mere. The dating results suggest that the open water core (HAT3) extends back to ~1800 AD and the marginal core extends back beyond ~17o00 AD. The palaeoecological data indicate that the site has been a moderately enriched lake for the whole of the period represented by the cores with diatom-inferred TP concentrations of ~30 μg L-1 in the lower part of the record. However, there were marked changes across a range of indicators from the early 1800s indicative of enrichment, which has continued through the twentieth century. The key changes were the expansion of the eutrophic diatom species Cyclostephanos dubius and hence an increase in diatom-inferred TP to ~84 μg L-1, a steady increase in pigment concentrations from all algal groups, and shifts in the zooplankton community indicative of increased pelagic productivity. Eutrophication has resulted in marked changes in the aquatic plant community from a structurally diverse flora with abundant Charophytes, nymphaeids and taxa with a mix of seasonalities to the current state with no submerged flora and only Nuphar lutea. The most notable changes in the macrofossil record have occurred from the mid-1800s and are, therefore, coincident with the main phase of enrichment. The dominance of the upper sediments by planktonic zooplankton and abundant Daphnia ephippia towards the top of the core, lends further weight to a plankton dominated system. This study provides information on the plant and animal communities that were present in the lake prior to the major eutrophication phase and this significantly alters the generic target previously set for the lake and will be valuable for setting targets for future management of the site

Tratamento de varizes retais de difícil controlo

Background: Rectal varices are portosystemic collaterals that arise as a complication of portal hypertension. Despite their significant prevalence among cirrhotic patients, clinically important bleeding occurs only in a minority. Various treatment options are available, with endoscopic therapies being widely used, and both interventional radiology and surgery being considered for refractory bleeding rectal varices. Case: We report the case of a 61-year-old male with hepatic cirrhosis and bleedingrectal varices refractory to endoscopic therapy, successfully managed with a combination of transjugular intrahepatic portosystemic shunt (TIPS) and selective variceal embolization. Conclusions: Radiological techniques are effective options for refractory bleeding. Adding embolization to TIPS implantation could represent a valid adjunctive measure for haemostasis of recurrent rectal variceal bleeding.Introdução: As varizes retais são colaterais portossistémicos que se formam como complicação da hipertensão portal. Apesar de serem frequentes em doentes com cirrose hepática, cursam com hemorragia apenas numa minoria dos casos. Entre as opções terapêuticas disponíveis, a endoscópica é a mais amplamente disponível e utilizada, sendo as intervenções da radiologia ou da cirurgia reservadas para casos de hemorragia refratária. Caso: Apresenta-se o caso de um homem de 61 anos com cirrose hepá­tica e hemorragia com ponto de partida em varizes retais. Por refratariedade ao tratamento endoscópico, uma combinação de shunt portossistémico intrahepático transjugu­lar e embolização seletiva das varizes retais foi necessária para uma hemóstase eficaz. Conclusão: A combinação do TIPS com a embolização seletiva das varizes retais é uma alternativa terapêutica na hemorragia por varizes retais refratárias a tratamento endoscópico.info:eu-repo/semantics/publishedVersio