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

An integrated database manager to forecast estuarine dynamics and water quality in the Guadalquivir river (Spain)

River engineeringFlow management and contro

Tales effect in real and perceived aquatic: Competence in preschoolers

Pese a existir un interés creciente en los estudios por la renovación de los contenidos lúdicos tradicionales, así como en la utilización del medio acuático como recurso educativo, en la actualidad existen muy pocas investigaciones que relacionen ambos aspectos. Por ello, el objetivo de este estudio cuasi-experimental fue comprobar el efecto de los cuentos motores acuáticos sobre la competencia motriz percibida y la capacidad motriz real. Los participantes fueron 16 infantes de 3 a 5 años a los que se le midió la competencia motriz real y percibida acuática. Tras una prueba no paramétrica los resultados mostraron que la administración del programa de cuentos motores contribuyó de manera positiva y significativa sobre la competencia motriz percibida del grupo experimental. Se discuten los resultados en pro de incluir en los programas educativos acuáticos los cuentos motores de cara a fomentar el autoconcepto infantilEven though a growing interest exists in the study of the renewal of the traditional ‘play’ curriculum, as well as the utilization of the aquatic medium as an educational resource, at present, very few studies link both areas. For this reason, the objective of this quasi-experimental study was to confirm the effect of aquatic motor tales over perceived motor competency and real motor capacity. We studied 16 preschoolers among 3 to 5 years of age for their real and perceived aquatic motor competency. After a non-parametric test was administered, the results show that administration of aquatic mobility stories contributed positively and significantly on the perceived motor competence of the experimental group. The results are discussed in favor of inclusion of aquatic educational programs in order to promote the self-esteem of this age-group

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

Steinberg modules and Donkin pairs

We prove that in positive characteristic a module with good filtration for a group of type E6 restricts to a module with good filtration for a subgroup of type F4. (Recall that a filtration of a module for a semisimple algebraic group is called good if its layers are dual Weyl modules.) Our result confirms a conjecture of Brundan for one more case. The method relies on the canonical Frobenius splittings of Mathieu. Next we settle the remaining cases, in characteristic not 2, with a computer-aided variation on the old method of Donkin.Comment: 16 pages; proof of Brundan's conjecture adde

Structural control on carbon emissions at the Nirano mud volcanoes – Italy

The Nirano Salse in Italy is a well-studied site where natural gas seepage (NGS) and other hydrocarbon fluids and gases are emitted at the earth's surface. A novel integrated approach is applied to define a comprehensive structural interpretation of the gas seepage and flow dynamic in the mud volcano system of the Nirano Salse Regional Nature Reserve (Modena, Northern Apennines). The paper investigates the relationship between gas emissions and local structures, particularly faults and fractures, in the shallow subsurface (down to 500–600 m depth) to understand the control that structures have on fluid ascent from deep leaky hydrocarbon traps. We performed continuous monitoring of mud levels within vents; carried out geological surveys to characterize the main stratigraphic and structural discontinuities; measured the carbon emissions (CH4 and CO2) seepage both from volcanoes and the surrounding soil by a portable gas fluxmeter; and integrated the results with available geophysical surveys. The authors argue that the transgressive Pleistocene-Pliocene Argille Azzurre Formation hides the complex and highly structured pre-Pliocene geology of the area, in which faults and fractures act as pathways for deep fluid ascent. The emissions are aligned along a NE-SW trend at the intersection of a NE-SW fracture system and NW-SE-oriented normal faults, which are both associated to the local tensional stress field of a likely left-lateral strike-slip transfer structure or in the extrados of a fold. By examining both natural gas macroseepage and diffuse flux, it is shown that local structures control the fluid ascent and contribute to the emission of hydrocarbon gases and fluids at the Earth's surface. Understanding the structural control of carbon emissions at the Nirano Salse is also important for evaluating the carbon budget at the site, particularly in areas where there are detectable surface emissions. The study has implications for geologic, environmental, and economic issues, including hydrocarbon exploration, hazard assessment, and impact on the atmospheric carbon budget. Furthermore, the outcomes have an important implication to evaluate the potential for dangerous abrupt mud eruptions, and the site safety in proximity to the mud volcanoes

HECT E3 Ligases : a Tale With Multiple Facets

Ubiquitination plays a pivotal role in several cellular processes and is critical for protein degradation and signaling. E3 ubiquitin ligases are the matchmakers in the ubiquitination cascade, responsible for substrate recognition. In order to achieve selectivity and specificity on their substrates, HECT E3 enzymes are tightly regulated and exert their function in a spatially and temporally controlled fashion in the cells. These characteristics made HECT E3s intriguing targets in drug discovery in the context of cancer biology

Marco Polo: A near Earth object sample return mission

From Introduction: MARCO POLO is a joint European-Japanese sample return mission to a Near-Earth Object. In late 2007 this mission was selected by ESA, in the framework of COSMIC VISION 2015-2025, for an assessment scheduled to last until mid 2009. This Euro-Asian mission will go to a primitive Near-Earth Object (NEO), such as a C or D type asteroid. The spacecraft will rendezvous with the object, and over an extended period scientifically characterize it at multiple scales and bring samples back to Earth for detailed scientific investigation

Ultrasound measurement of the effects of high, medium and low hip long-axis distraction mobilization forces on the joint space width and its correlation with the joint strain

Background: No study has evaluated the mechanical effect of different magnitudes of long axis-distraction mobilization (LADM) force on hip joint space width (JSW) or the association between the separation of joint surfaces and the strain on hip capsular ligaments. Objective: To compare the joint separation when applying three different magnitudes of LADM forces (low, medium and high) and to analyse the correlation between joint separation, strain on the inferior ilio-femoral ligament and magnitude of applied force. Design: Repeated measures controlled laboratory cadaveric study. Methods: Three magnitudes of force were applied to 11 cadaveric hip joints (mean age 73 years). Ultrasound images were used to measure joint separation, and strain gauges recorded inferior ilio-femoral ligament strain during each condition. Results: The magnitude of joint separation was significantly different between low (0.23 ± 0.19 mm), medium (0.72 ± 0.22 mm) and high (2.62 ± 0.43 mm) forces (p 0.723; p < 0.001). Conclusion: Hip joint separation and ligament strain during LADM are associated with the magnitude of the applied force

Comparison of the Immune Responses Induced by Chimeric Alphavirus-Vectored and Formalin-Inactivated Alum-Precipitated Measles Vaccines in Mice

A variety of vaccine platforms are under study for development of new vaccines for measles. Problems with past measles vaccines are incompletely understood and underscore the need to understand the types of immune responses induced by different types of vaccines. Detailed immune response evaluation is most easily performed in mice. Although mice are not susceptible to infection with wild type or vaccine strains of measles virus, they can be used for comparative evaluation of the immune responses to measles vaccines of other types. In this study we compared the immune responses in mice to a new protective alphavirus replicon particle vaccine expressing the measles virus hemagglutinin (VEE/SIN-H) with a non-protective formalin-inactivated, alum-precipitated measles vaccine (FI-MV). MV-specific IgG levels were similar, but VEE/SIN-H antibody was high avidity IgG2a with neutralizing activity while FI-MV antibody was low-avidity IgG1 without neutralizing activity. FI-MV antibody was primarily against the nucleoprotein with no priming to H. Germinal centers appeared, peaked and resolved later for FI-MV. Lymph node MV antibody-secreting cells were more numerous after FI-MV than VEE/SIN-H, but were similar in the bone marrow. VEE/SIN-H-induced T cells produced IFN-γ and IL-4 both spontaneously ex vivo and after stimulation, while FI-MV-induced T cells produced IL-4 only after stimulation. In summary, VEE/SIN-H induced a balanced T cell response and high avidity neutralizing IgG2a while FI-MV induced a type 2 T cell response, abundant plasmablasts, late germinal centers and low avidity non-neutralizing IgG1 against the nucleoprotein