Semiclassical strings and Non-Abelian T-duality

We study semiclassical strings in the Klebanov-Witten and in the Non-abelian T-dual Klebanov-Witten backgrounds. We show that both backgrounds share a subsector of equivalent states up to conditions on the T-dual coordinates which also impose a breaking of the R-symmetry by a discrete group. We also analyze string configurations where the strings are stretched along the T-dual coordinates. This semiclassical analysis predicts the existence of chiral primary operators for the dual (strongly coupled) superconformal field theory whose anomalous dimension depends on the T-dual coordinates. We briefly discuss the Penrose limit of the dualised background.Comment: 18 pages. arXiv admin note: text overlap with arXiv:1305.7229 by other author

TÉCNICAS DE AISLAMIENTO Y PURIFICACIÓN DE OOQUISTES DE Sarcocystis aucheniae A PARTIR DE INTESTINO DELGADO DE PERROS EXPERIMENTALMENTE INFECTADOS

Procedures were evaluated for the rapid and efficient purification of oocysts and esporocysts of Sarcocystis aucheniae (Sa) from the small intestine of experimentally infected dogs with 400 Sa macrocysts obtained from meat of naturally infected alpacas. The mucosa of the small intestine was removed. Samples were washed by centrifugation with PBS, homogenized and centrifuged. Large quantities of oocysts attached to the intestinal microvilli were obtained. In the first procedure, an ezimatic treatment with 5% tripsin was used resulting in 50% oocyst separation. In the second procedure samples were treated with 2.6% sodium hypoclorite solution achieving 80% separation. In the third procedure, samples were centrifuged with a discontinuous density gradient of potassium bromide rendering 99% oocyst separation. The later procedure allowed obtaining relevant quantities of purified Sa oocysts and without loss of viability.Se evalúan procedimientos para la rápida y eficiente purificación de ooquistes y eporoquistes de Sarcocystis aucheniae (Sa), a partir del intestino delgado de perros experimentalmente infectados vía oral con 400 macroquistes de Sa provenientes de carne de alpacas naturalmente infectadas. Se recolectó la mucosa del intestino delgado. Las muestras fueron lavadas por centrifugación con buffer salino fosfato y homogenizadas y centrifugadas. Se obtuvo grandes cantidades de ooquistes adheridos a las microvellosidades intestinales. En el primer procedimiento, los ooquistes recibieron un tratamiento enzimático con tripsina al 5% resultando 50% de separación. En el segundo fueron tratados con una solución de hipoclorito de sodio al 2.6% lográndose una separación parcial (80%). En el tercero fueron centrifugados con una gradiente de densidad discontinua de bromuro de potasio obteniéndose una separación de 99%. Este último procedimiento permitió la obtención de ooquistes de Sa en cantidades relevantes, purificados y sin pérdida de la viabilidad

Extracellular ATP released by osteoblasts is a key local inhibitor of bone mineralisation

Previous studies have shown that exogenous ATP (>1µM) prevents bone formation in vitro by blocking mineralisation of the collagenous matrix. This effect is thought to be mediated via both P2 receptor-dependent pathways and a receptor-independent mechanism (hydrolysis of ATP to produce the mineralisation inhibitor pyrophosphate, PPi). Osteoblasts are also known to release ATP constitutively. To determine whether this endogenous ATP might exert significant biological effects, bone-forming primary rat osteoblasts were cultured with 0.5-2.5U/ml apyrase (which sequentially hydrolyses ATP to ADP to AMP + 2Pi). Addition of 0.5U/ml apyrase to osteoblast culture medium degraded extracellular ATP to <1% of control levels within 2 minutes; continuous exposure to apyrase maintained this inhibition for up to 14 days. Apyrase treatment for the first 72 hours of culture caused small decreases (≤25%) in osteoblast number, suggesting a role for endogenous ATP in stimulating cell proliferation. Continuous apyrase treatment for 14 days (≥0.5U/ml) increased mineralisation of bone nodules by up to 3-fold. Increases in bone mineralisation were also seen when osteoblasts were cultured with the ATP release inhibitors, NEM and brefeldin A, as well as with P2X1 and P2X7 receptor antagonists. Apyrase decreased alkaline phosphatase (TNAP) activity by up to 60%, whilst increasing the activity of the PPi-generating ecto-nucleotide pyrophosphatase/phosphodiesterases (NPPs) up to 2.7-fold. Both collagen production and adipocyte formation were unaffected. These data suggest that nucleotides released by osteoblasts in bone could act locally, via multiple mechanisms, to limit mineralisation

Body composition by dual X-ray absorptiometry in Mexican schoolchildren with or without obesity

Objective: Apply dual X-ray absorptiometry (DXA) to determine the amount of fat mass, lean mass, and bone mineral density in Mexican schoolchildren with and without obesity. Material and methods: We performed an observational, analytical, comparative, cross-sectional study of 80 Mexican schoolchildren who attended the Nutrition Clinic of the Pediatric Medical Center in Monterrey, Mexico during the period of January to April 2005. Body mass index (BMI) was determined to classify the participants according to the growth charts of the Centers for Disease Control and Prevention. Two groups of 40 children each (with and without obesity) were formed and DXA was carried out on each individual. Cronbach’s Alpha was used to determine instrument reliability and the Kolmogorov-Smirnov test was used to test the normality of numerical variables. Means were compared using Student´s t test. Results: Statistically signiicant differences were found in fat mass (p≤0.001) and lean mass (p≤0.001), but not in bone mineral content (p=0.051) between both groups. Conclusions: Differences exist in fat mass and lean mass in both groups, but not in bone mineral content between both groups. A signiicant positive correlation was found between fat mass, determined by DXA, and BMI in schoolchildren with and without obesit

Holographic flows in non-Abelian T-dual geometries

We use non-Abelian T-duality to construct new N=1 solutions of type IIA supergravity (and their M-theory lifts) that interpolate between AdS_5 geometries. We initiate a study of the holographic interpretation of these backgrounds as RG flows between conformal fixed points. Along the way we give an elegant formulation of non-Abelian T-duality when acting on a wide class of backgrounds, including those corresponding to such flows, in terms of their SU(2) structure

BMN vacua, superstars and non-abelian T-duality

Acting with non-Abelian T-duality on the $S^3$ inside the $AdS_5$ subspace of $AdS_5\times S^5$ with $N$ units of flux, we generate a new half-BPS solution with $SU(2|4)$ symmetry that belongs to the Lin-Lunin-Maldacena class of geometries. The analysis of the asymptotics, quantised charges and probe branes in this geometry suggests an interpretation as the gravity dual to the Berenstein-Maldacena-Nastase Plane Wave Matrix Model, in a particular vacuum associated to a partition of $N$, in which the multiplicity of each $SU(2)$ irreducible representation is equal to its dimension. This vacuum is interpreted in M-theory in terms of giant gravitons backreacting in the maximally supersymmetric pp-wave geometry. Consistently with this, we show that the non-Abelian T-dual solution exactly agrees with the Penrose limit of the superstar solution in $AdS_7\times S^4$. This suggests an interesting global completion of the non-Abelian T-dual solution in terms of an M5-brane geometry.Comment: 28 pages, discussion in section 5.1 improved, results unchanged, reference added. Matches published versio