Dynamics for a 2-vertex Quantum Gravity Model

We use the recently introduced U(N) framework for loop quantum gravity to study the dynamics of spin network states on the simplest class of graphs: two vertices linked with an arbitrary number N of edges. Such graphs represent two regions, in and out, separated by a boundary surface. We study the algebraic structure of the Hilbert space of spin networks from the U(N) perspective. In particular, we describe the algebra of operators acting on that space and discuss their relation to the standard holonomy operator of loop quantum gravity. Furthermore, we show that it is possible to make the restriction to the isotropic/homogeneous sector of the model by imposing the invariance under a global U(N) symmetry. We then propose a U(N) invariant Hamiltonian operator and study the induced dynamics. Finally, we explore the analogies between this model and loop quantum cosmology and sketch some possible generalizations of it.Comment: 28 pages, v2: typos correcte

Effect of the Influent COD Concentration on the Anaerobic Digestion of Winery Wastewaters from Grape-Red and Tropical Fruit (Guava) Wine Production in Fluidized Bed Reactors with Chilean Natural Zeolite for Biomass Immobilization

The effect of the influent COD concentration on the performance of anaerobic fluidized bed reactors treating winery wastewaters from grape-red wine (GRWW) and guava wine production (GWW) was studied at laboratory scale. Two reactors were used: one treating GRWW (AFB1) and the other processing GWW (AFB2). The behaviour of these reactors packed with Chilean zeolite as biomass immobilization support was compared at mesophilic temperature (35 °C). Influent COD varied from γ = 1–24 g L–1 and the HRT was maintained constant at 1 day throughout the experiment. During the experiment, influent and effluent pH, TVFA, COD and methane gas production were determined. COD removal efficiency increased with the influent COD up to a maximum of around γ = 19 g L–1 for GRWW and up to around 22 g L–1 for GWW due to the increase of the concentration of phenols. Process performance was slightly better with guava winery wastewater than with grape-red winery wastewater due its lower phenolic content. During the period of non-inhibition the methane yield was virtually constant

Blood lead levels in pregnant women of high and low socioeconomic status in Mexico City.

This study examined the determinants of blood lead (BPb) in 513 pregnant women in Mexico City: 311 from public hospital prenatal clinics, representing primarily women of low socioeconomic status (SES), and 202 from private hospitals, primarily women of high SES. Overall, BPb levels ranged from 1.38 to 29 micrograms/dl, with geometric means of 6.7 and 11.12 micrograms/dl for women from private and public hospitals, respectively. The crude geometric means difference obtained by t-test was 4.42 (p < 0.001). BPb was measured from January 1994 to August 1995 and showed higher levels during fall and winter and lower levels during spring and summer. The main BPb determinants were the use of lead-glazed ceramics in women from public hospitals and season of the year in women from private hospitals. Consumption of tortillas (corn bread rich in calcium) decreased BPb levels in the lower SES group, but the relationship was not statistically significant (p > 0.05). Consumption of milk products significantly (p < 0.05) reduced BPb levels in the higher SES group. In 112 women whose diets were deficient in calcium, taking calcium supplements lowered their blood lead levels about 7 micrograms/dl. A predictive model fitted to these data, using the strongest predictors plus gestational age, showed a difference of 14 micrograms/dl between the best and worst scenarios in women from public hospitals. Avoiding use of lead-glazed ceramics, consuming diets rich in calcium, and, if needed, taking calcium supplements, would be expected to result in substantial lowering of BPb, especially in pregnant women of low socioeconomic status

Prevalence of depressive symptoms in pregnant and postnatal HIV-positive women in Ukraine: a cross-sectional survey.

BACKGROUND: Perinatal depression among HIV-positive women has negative implications for HIV-related and other maternal and infant outcomes. The aim of this study was to investigate the burden and correlates of perinatal depression among HIV-positive women in Ukraine, a lower middle income country with one of the largest HIV-positive populations in Europe. METHODS: Cross-sectional surveys nested within the Ukraine European Collaborative Study were conducted of HIV-positive women at delivery and between 1 and 12 months postpartum. Depressive symptoms in the previous month were assessed using a self-report screening tool. Other data collected included demographics, antiretroviral therapy (ART)-related self-efficacy, and perceptions of risks/benefits of interventions to prevent mother-to-child transmission (PMTCT). Characteristics of women with and without a positive depression screening test result were compared using Fisher's exact test and χ(2) test for categorical variables. RESULTS: A quarter (27 % (49/180) antenatally and 25 % (57/228) postnatally) of participants screened positive for depressive symptoms. Antenatal risk factors were living alone (58 % (7/12) vs 25 % (42/167) p = 0.02), being somewhat/terribly bothered by ART side effects (40 % (17/43) vs 23 % (30/129) not /only slightly bothered, p = 0.05) and having lower ART-related self-efficacy (43 % (12/28) vs 23 % (25/110) with higher self-efficacy, p = 0.05). Postnatally, single mothers were more likely to screen positive (44 % (20/45) vs 21 % (18/84) of cohabiting and 19 % (19/99) of married women, p < 0.01) as were those unsure of the effectiveness of neonatal prophylaxis (40 % (20/45) vs 18 % (28/154) sure of effectiveness, p < 0.01), those worried that neonatal prophylaxis could harm the baby (30 % (44/146) vs 14 % (10/73) not worried p < 0.01) and those not confident to ask for help with taking ART (48 % (11/23) vs 27 % (10/37) fairly confident and 15 % (4/26) confident that they could do this). Of women who reported wanting help for their depressive symptoms, 82 % (37/45) postnatally but only 31 % (12/39) antenatally were already accessing peer counselling, treatment adherence programmes, support groups or social services. CONCLUSIONS: A quarter of women screened positive for depression. Results highlight the need for proactive strategies to identify depressive symptoms, and an unmet need for provision of mental health support in the perinatal period for HIV-positive women in Ukraine

Consumo de nutriente em cordeiros alimentados com torta de dendê.

Objetivou-se determinar o nível ideal da torta de dendê na dieta, por intermédio de consumo. O experimento foi conduzido no aprisco da Escola de Medicina Veterinária da UFBA, Salvador-BA, com duração de 80 dias. Foram utilizados trinta e dois cordeiros de raça Santa Inês, com peso vivo inicial de aproximadamente 22 kg, entre quatro a seis meses de idade. Os tratamentos consistiram de quatro níveis (0; 6,5; 13,0 e 19,5%) de inclusão de torta de dendê na matéria seca da dieta. As dietas foram fornecidas duas vezes ao dia (ás 9 e 16 h), na forma de ração total, em quantidade ajustada para ocorrer 10 a 20% das sobras. Os consumos de matéria seca, de matéria orgânica, de proteína bruta e de carboidratos nãofibrosos seguiram comportamento linear decrescente com adição dos níveis de torta de dendê na dieta (p0,05)

Impact of expanded access to combination antiretroviral therapy in pregnancy: results from a cohort study in Ukraine

To investigate the scale-up of antenatal combination antiretroviral therapy (cART) in Ukraine since this became part of the national policy for the prevention of mother-to-child transmission (PMTCT) of human immunodeficiency virus (HIV)

Revisiting the Simplicity Constraints and Coherent Intertwiners

In the context of loop quantum gravity and spinfoam models, the simplicity constraints are essential in that they allow to write general relativity as a constrained topological BF theory. In this work, we apply the recently developed U(N) framework for SU(2) intertwiners to the issue of imposing the simplicity constraints to spin network states. More particularly, we focus on solving them on individual intertwiners in the 4d Euclidean theory. We review the standard way of solving the simplicity constraints using coherent intertwiners and we explain how these fit within the U(N) framework. Then we show how these constraints can be written as a closed u(N) algebra and we propose a set of U(N) coherent states that solves all the simplicity constraints weakly for an arbitrary Immirzi parameter.Comment: 28 page

The histone deacetylase inhibitor valproic acid attenuates phospholipase Cγ2 and IgE-mediated mast cell activation.

Mast cell activation through the high-affinity IgE receptor (FcεRI) plays a central role in allergic reactions. FcεRI-mediated activation triggers multiple signaling pathways leading to degranulation and synthesis of different inflammatory mediators. IgE-mediated mast cell activation can be modulated by different molecules, including several drugs. Herein, we investigated the immunomodulatory activity of the histone deacetylase inhibitor valproic acid (VPA) on IgE-mediated mast cell activation. To this end, bone marrow-derived mast cells (BMMC) were sensitized with IgE and treated with VPA followed by FcεRI cross-linking. The results indicated that VPA reduced mast cell IgE-dependent degranulation and cytokine release. VPA also induced a significant reduction in the cell surface expression of FcεRI and CD117, but not other mast cell surface molecules. Interestingly, VPA treatment inhibited the phosphorylation of PLCγ2, a key signaling molecule involved in IgE-mediated degranulation and cytokine secretion. However, VPA did not affect the phosphorylation of other key components of the FcεRI signaling pathway, such as Syk, Akt, ERK1/2, or p38. Altogether, our data demonstrate that VPA affects PLCγ2 phosphorylation, which in turn decreases IgE-mediated mast cell activation. These results suggest that VPA might be a key modulator of allergic reactions and might be a promising therapeutic candidate