On the Origin of the -4.4 eV Band in CdTe(100)"

We calculate the bulk- (infinite system), (100)-bulk-projected- and (100)-Surface-projected Green's functions using the Surface Green's Function Matching method (SGFM) and an empirical tight-binding hamiltonian with tight-binding parameters (TBP) that describe well the bulk band structure of CdTe. In particular, we analyze the band (B--4) arising at --4.4 eV from the top of the valence band at $\Gamma$ according to the results of Niles and H\"ochst and at -4.6 eV according to Gawlik {\it et al.} both obtained by Angle-resolved photoelectron spectroscopy (ARPES). We give the first theoretical description of this band.Comment: 17 pages, Rev-TEX, CIEA-Phys. 02/9

Nifedipine Treatment Reduces Resting Calcium Concentration, Oxidative and Apoptotic Gene Expression, and Improves Muscle Function in Dystrophic mdx Mice

Duchenne Muscular Dystrophy (DMD) is a recessive X-linked genetic disease, caused by mutations in the gene encoding dystrophin. DMD is characterized in humans and in mdx mice by a severe and progressive destruction of muscle fibers, inflammation, oxidative/nitrosative stress, and cell death. In mdx muscle fibers, we have shown that basal ATP release is increased and that extracellular ATP stimulation is pro-apoptotic. In normal fibers, depolarization-induced ATP release is blocked by nifedipine, leading us to study the potential therapeutic effect of nifedipine in mdx muscles and its relation with extracellular ATP signaling. Acute exposure to nifedipine (10 µM) decreased [Ca2+]r, NF-κB activity and iNOS expression in mdx myotubes. In addition, 6-week-old mdx mice were treated with daily intraperitoneal injections of nifedipine, 1 mg/Kg for 1 week. This treatment lowered the [Ca2+]r measured in vivo in the mdx vastus lateralis. We demonstrated that extracellular ATP levels were higher in adult mdx flexor digitorum brevis (FDB) fibers and can be significantly reduced after 1 week of treatment with nifedipine. Interestingly, acute treatment of mdx FDB fibers with apyrase, an enzyme that completely degrades extracellular ATP to AMP, reduced [Ca2+]r to a similar extent as was seen in FDB fibers after 1-week of nifedipine treatment. Moreover, we demonstrated that nifedipine treatment reduced mRNA levels of pro-oxidative/nitrosative (iNOS and gp91phox/p47phox NOX2 subunits) and pro-apoptotic (Bax) genes in mdx diaphragm muscles and lowered serum creatine kinase (CK) levels. In addition, nifedipine treatment increased muscle strength assessed by the inverted grip-hanging test and exercise tolerance measured with forced swimming test in mdx mice. We hypothesize that nifedipine reduces basal ATP release, thereby decreasing purinergic receptor activation, which in turn reduces [Ca2+]r in mdx skeletal muscle cells. The results in this work open new perspectives towards possible targets for pharmacological approaches to treat DMD

Characterization and production of shiitake (Lentinula edodes) in Mexico using supplemented sawdust

The cultivation of shiitake in Latin America started during the early 1980's, and several attempts for its commercial cultivation have been carried out during the last decade in Guatemala, Colombia, Mexico, Argentina and Brazil. However, a major constrain has been the lack of basic research, allowing further development. In this work, we studied two genotypes of Lentinula edodes (CP-7 and CP-163) selected from 16 strains being used in the region at different levels, in order to assess their mycelial growth rate in Petri dishes, as well as yield (biologic efficiency, production rate) and quality of fruit bodies, using 10 different formulations of supplemented sawdust from a common Mexican oak tree (Quercus acutifolia Neé). The best mycelial development was 8.5 mm/day for the genotype CP-163 cultivated on 70% Quercus sawdust, 10% corn-cobs, 10% maize stubble, 7% wheat bran and 3% rice meal. The highest yield was recorded in the genotype CP-7, using 60% Quercus sawdust, 28.5% corn-cobs, 10% maize stubble, 1.5% gypsum, thiamine (100 mg/kg), and magnesium sulfate (20 g/100 kg); reaching a biologic efficiency of 103%, a production rate of 1.3, and a high proportion (41.8%) of fruit bodies, having good commercial quality (41 to 70 g fresh weight, > 12 cm cap diameter and 96.5% of regular shape). On the basis of this study, this last genotype and formulation was recommended, as well as to establish a breeding program at the molecular level for shiitake production on a large scale in Mexico or other Latin American countries.Keywords: Edible mushrooms, genotypes, substrates, mycelial growth rate, biologic efficienc

Multiple and Precessing Collimated Outflows in the Planetary Nebula IC 4634

With its remarkable double-S shape, IC 4634 is an archetype of point-symmetric planetary nebulae (PN). In this paper, we present a detailed study of this PN using archival HST WFPC2 and ground-based narrow-band images to investigate its morphology, and long-slit spectroscopic observations to determine its kinematics and to derive its physical conditions and excitation. The data reveal new structural components, including a distant string of knots distributed along an arc-like feature 40"-60" from the center of the nebula, a skin of enhanced [O III]/H-alpha ratio enveloping the inner shell and the double-S feature, and a triple-shell structure. The spatio-kinematical study also finds an equatorial component of the main nebula that is kinematically independent from the bright inner S-shaped arc. We have investigated in detail the bow shock-like features in IC 4634 and found that their morphological, kinematical and emission properties are consistent with the interaction of a collimated outflow with surrounding material. Indeed, the morphology and kinematics of some of these features can be interpreted using a 3D numerical simulation of a collimated outflow precessing at a moderate, time-dependent velocity. Apparently, IC 4634 has experienced several episodes of point-symmetric ejections oriented at different directions with the outer S-shaped feature being related to an earlier point-symmetric ejection and the outermost arc-like string of knots being the relic of an even much earlier point-symmetric ejection. There is tantalizing evidence that the action of these collimated outflows has also taken part in the shaping of the innermost shell and inner S-shaped arc of IC 4634.Comment: 16 pages, 11 figures, accepted for publication in The Astrophysical Journa

First release of the IPHAS catalogue of new extended planetary nebulae

Date of Acceptance: 30/06/2014We present the first results of our search for new, extended planetary nebulae (PNe) based on careful, systematic, visual scrutiny of the imaging data from the Isaac Newton Telescope Photometric Ha Survey of the Northern Galactic plane (IPHAS). The newly uncovered PNe will help to improve the census of this important population of Galactic objects that serve as key windows into the late-stage evolution of low- to intermediate-mass stars. They will also facilitate study of the faint end of the ensemble Galactic PN luminosity function. The sensitivity and coverage of IPHAS allows PNe to be found in regions of greater extinction in the Galactic plane and/or those PNe in a more advanced evolutionary state and at larger distances compared to the general Galactic PN population. Using a set of newly revised optical diagnostic diagrams in combination with access to a powerful, new, multiwavelength imaging data base, we have identified 159 true, likely and possible PNe for this first catalogue release. The ability of IPHAS to unveil PNe at low Galactic latitudes and towards the Galactic Anticentre, compared to previous surveys, makes this survey an ideal tool to contribute to the improvement of our knowledge of the whole Galactic PN population.Peer reviewe

Modelo para un servicio de mensajería instantánea sobre redes oportunistas con dispositivos móviles

Este trabajo presenta un modelo para una aplicación de mensajería instantánea sobre redes oportunistas formada por dispositivos móviles. El servicio admite el envío y recepción de mensajes, en ausencia de una infraestructura de red, o cuando la conexión es intermitente o limitada. Para ello, se emplean algoritmos de ruteo para redes tolerantes a demoras, algoritmos de descubrimiento de nodos vecinos, y se estudian las interfaces de comunicación de dispositivos móviles actuales. Se identifican problemas y dificultades para una implementación de los métodos y diseños propuestos en la literatura.Sociedad Argentina de Informática e Investigación Operativa (SADIO