The Renormalization Group Limit Cycle for the 1/r^2 Potential

Previous work has shown that if an attractive 1/r^2 potential is regularized at short distances by a spherical square-well potential, renormalization allows multiple solutions for the depth of the square well. The depth can be chosen to be a continuous function of the short-distance cutoff R, but it can also be a log-periodic function of R with finite discontinuities, corresponding to a renormalization group (RG) limit cycle. We consider the regularization with a delta-shell potential. In this case, the coupling constant is uniquely determined to be a log-periodic function of R with infinite discontinuities, and an RG limit cycle is unavoidable. In general, a regularization with an RG limit cycle is selected as the correct renormalization of the 1/r^2 potential by the conditions that the cutoff radius R can be made arbitrarily small and that physical observables are reproduced accurately at all energies much less than hbar^2/mR^2.Comment: 11 pages, 4 figure

Inflammaging as a prodrome to Alzheimer's disease

Recently, the term "inflammaging" was coined by Franceshci and colleagues to characterize a widely accepted paradigm that ageing is accompanied by a low-grade chronic up-regulation of certain pro-inflammatory responses. Inflammaging differs significantly from the traditional five cardinal features of acute inflammation in that it is characterized by a relative decline in adaptive immunity and T-helper 2 responses and is associated with increased innate immunity by cells of the mononuclear phagocyte lineage. While the over-active innate immunity characteristic of inflammaging may remain subclinical in many elderly individuals, a portion of individuals (postulated to have a "high responder inflammatory genotype") may shift from a state of "normal" or "subclinical" inflammaging to one or more of a number of age-associated diseases. We and others have found that IFN-γ and other pro-inflammatory cytokines interact with processing and production of Aβ peptide, the pathological hallmark feature of Alzheimer's disease (AD), suggesting that inflammaging may be a "prodrome" to AD. Although conditions of enhanced innate immune response with overproduction of pro-inflammatory proteins are associated with both healthy aging and AD, it is suggested that those who age "well" demonstrate anti-inflammaging mechanisms and biomarkers that likely counteract the adverse immune response of inflammaging. Thus, opposing the features of inflammaging may prevent or treat the symptoms of AD. In this review, we fully characterize the aging immune system. In addition, we explain how three novel treatments, (1) human umbilical cord blood cells (HUCBC), (2) flavanoids, and (3) Aβ vaccination oppose the forces of inflammaging and AD-like pathology in various mouse models

Functional evolution of quantum cylindrical waves

Kucha{\v{r}} showed that the quantum dynamics of (1 polarization) cylindrical wave solutions to vacuum general relativity is determined by that of a free axially-symmetric scalar field along arbitrary axially-symmetric foliations of a fixed flat 2+1 dimensional spacetime. We investigate if such a dynamics can be defined {\em unitarily} within the standard Fock space quantization of the scalar field. Evolution between two arbitrary slices of an arbitrary foliation of the flat spacetime can be built out of a restricted class of evolutions (and their inverses). The restricted evolution is from an initial flat slice to an arbitrary (in general, curved) slice of the flat spacetime and can be decomposed into (i) `time' evolution in which the spatial Minkowskian coordinates serve as spatial coordinates on the initial and the final slice, followed by (ii) the action of a spatial diffeomorphism of the final slice on the data obtained from (i). We show that although the functional evolution of (i) is unitarily implemented in the quantum theory, generic spatial diffeomorphisms of (ii) are not. Our results imply that a Tomanaga-Schwinger type functional evolution of quantum cylindrical waves is not a viable concept even though, remarkably, the more limited notion of functional evolution in Kucha{\v{r}}'s `half parametrized formalism' is well-defined.Comment: Replaced with published versio

Evaluación de formulaciones matemáticas alternativas para la planeación óptima de flotas de vehículos bajo incertidumbre

El dimensionamiento y planeación de flotas de vehículos es un proceso crítico en toda industria que requiera el abastecimiento de materiales y servicios en sitios geográficamente distribuidos. Con frecuencia, la demanda de estas operaciones es incierta y produce serias dificultades en la gestión de contratos y en la asignación eficiente de vehículos para alcanzar los niveles de servicio requeridos a costos razonables. El presente trabajo tiene como objetivo revisar, validar y comparar dos de las principales contribuciones de los últimos años relativas al dimensionamiento y planificación de flotas de vehículos bajo condiciones inciertas. Para ello, se proponen casos de estudios de referencia que se resuelven para evaluar el desempeño de ambas formulaciones con el objetivo de delinear conclusiones en torno a sus capacidades. En particular, se establece una comparación exhaustiva de abordajes novedosos mediante programación matemática mixta-entera lineal con los tradicionales enfoques de programación estocástica propuestos en la literatura. En todos los casos, se busca establecer la mejor estrategia de contratación de vehículos, bajo diferentes alternativas de adquisición, y su correspondiente preasignación a servicios con un fuerte carácter aleatorio, con el objetivo de minimizar los costos de contratación e incumplimiento esperado de la demanda. En resumen, la exposición busca brindar lineamientos generales para la adopción de herramientas de planificación de flotas, comparando abordajes modernos (donde el nivel de servicio constituye una variable de decisión de los modelos de optimización), con formulaciones estocásticas afianzadas (en donde las decisiones de primer y segundo nivel se optimizan en torno a valores esperados de demanda). Se establecen importantes conclusiones acerca de la flexibilidad y precisión de cada uno de los enfoques.Sociedad Argentina de Informática e Investigación Operativ

The onset of circulation triggers a metabolic switch required for endothelial to hematopoietic transition

Hematopoietic stem cells (HSCs) emerge during development from the vascular wall of the main embryonic arteries. The onset of circulation triggers several processes that provide critical external factors for HSC generation. Nevertheless, it is not fully understood how and when the onset of circulation affects HSC emergence. Here we show that in Ncx1-/- mouse embryos devoid of circulation the HSC lineage develops until the phenotypic pro-HSC stage. However, these cells reside in an abnormal microenvironment, fail to activate the hematopoietic program downstream of Runx1, and are functionally impaired. Single-cell transcriptomics shows that during the endothelial-to-hematopoietic transition, Ncx1-/- cells fail to undergo a glycolysis to oxidative phosphorylation metabolic switch present in wild-type cells. Interestingly, experimental activation of glycolysis results in decreased intraembryonic hematopoiesis. Our results suggest that the onset of circulation triggers metabolic changes that allow HSC generation to proceed

Contenido de biopéptidos y actividad antihipertensiva in vitro de carne de cordero de diferentes sistemas de producción

Los péptidos bioactivos presentes en diversos alimentos son objetivo de estudio ya que se ha encontrado que cumplen diversos roles fisiológicos que impactan positivamente en la salud. En particular, en el músculo esquelético pueden encontrarse tanto dipéptidos antioxidantes endógenos como proteínas precursoras de péptidos bioactivos, los cuales pueden ser liberados por acción de las enzimas digestivas una vez que son consumidos. El objetivo de este trabajo fue estudiar la influencia del sistema de producción sobre el contenido de dos péptidos endógenos, carnosina y anserina, en carne de cordero y la actividad antihipertensiva in vitro luego de simular un proceso de digestión gastrointestinal. Los resultados obtenidos respecto a los dipéptidos no presentaron diferencias estadísticamente significativas en cuanto al sistema de producción empleado. En cuanto a la actividad antihipertensiva se halló una inhibición de la enzima convertidora de angiotensina (ECA) del 50%, no habiendo diferencias estadísticamente significativas entre los sistemas estudiados. La presencia de estos dipéptidos y la manifestación de la actividad antihipertensiva in vitro valorizan la carne de cordero desde el punto de vista nutracético/funcional y aportan información sobre los beneficios del consumo de dicha carneFil: Chamorro, Verónica Celeste. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina.Fil: Peranic, V. Universidad de Morón. Facultad de Agronomía y Ciencias Agroalimentarias; Argentina.Fil: Godoy, Maria Fernanda. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina.Fil: Bain, Ingrid. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Chubut; Argentina.Fil: Ceballos, Demian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Esquel; Argentina.Fil: Grigioni, Gabriela Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Morón; Argentina.Fil: Pighin, Darío Gabriel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Morón; Argentina.Fil: Pazos, Adriana Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina. Universidad de Morón; Argentina

A simulated “Night-onCall” to assess and address the readiness-for-internship of transitioning medical students

Transitioning medical students are anxious about their readiness-for-internship, as are their residency program directors and teaching hospital leadership responsible for care quality and patient safety. A readiness-for-internship assessment program could contribute to ensuring optimal quality and safety and be a key element in implementing competency-based, time-variable medical education. In this paper, we describe the development of the Night-onCall program (NOC), a 4-h readiness-for-internship multi-instructional method simulation event. NOC was designed and implemented over the course of 3 years to provide an authentic “night on call” experience for near graduating students and build measurements of students’ readiness for this transition framed by the Association of American Medical College’s Core Entrustable Professional Activities for Entering Residency. The NOC is a product of a program of research focused on questions related to enabling individualized pathways through medical training. The lessons learned and modifications made to create a feasible, acceptable, flexible, and educationally rich NOC are shared to inform the discussion about transition to residency curriculum and best practices regarding educational handoffs from undergraduate to graduate education

Structure and Genetic Variability of the Oceanic Whitetip Shark, Carcharhinus longimanus, Determined Using Mitochondrial DNA

Information regarding population structure and genetic connectivity is an important contribution when establishing conservation strategies to manage threatened species. The oceanic whitetip shark, Carcharhinus longimanus, is a highly migratory, large-bodied, pelagic shark listed by the IUCN (International Union for Conservation of Nature) Red List as "vulnerable" throughout its range and "critically endangered" in the western north Atlantic. In 2014, the species was protected globally under Appendix II of CITES (Convention on International Trade in Endangered Species), limiting and regulating trade. This study used partial sequences of mitochondrial DNA (mtDNA) control region to determine the population genetic structure of oceanic whitetip sharks across the Atlantic and Indian Oceans. 724 base pairs were obtained from 215 individuals that identifed nine polymorphic sites and defined 12 distinct haplotypes. Total nucleotide diversity (pi) was 0.0013 and haplotype diversity (h) was 0.5953. The Analysis of Molecular Variance (AMOVA) evidenced moderate levels of population structure (phi(ST) = 0.1039) with restricted gene flow between the western and eastern Atlantic Ocean, and a strong relationship between the latter region and the Indian Ocean. Even though the oceanic whitetip is a highly migratory animal the results presented here show that their genetic variability is slightly below average of other pelagic sharks. Additionally, this study recommends that at least two populations in the Atlantic Ocean should be considered distinct (eastern and western Atlantic) and conservation efforts should be focused in areas with the greatest genetic diversity by environmental managers