Climate- and Eustasy-Driven Cyclicity in Pennsylvanian Fusulinid Assemblages, Donets Basin (Ukraine)

A model of cyclic recurrence (~ 0.6–1.2 myr) of three fusulinid assemblages in the Middle Pennsylvanian siliciclastic–carbonate succession of the Donets Basin is proposed. Each cycle records progressive turnover of assemblages in shallow marine environments in response to sea-level and regional climate change. A Hemifusulina-assemblage (A), adapted to cooler and reduced salinity seawater records the onset of sea level rise accompanied by humid climatic conditions. Sea level high stand is captured by the Beedeina–Neostaffella–Ozawainella–Taitzehoella (or Beedeina-dominated) assemblage (B), characteristic of relatively deeper-water environments. The B assemblage is successively replaced by the most diverse population of the warm-water Fusulinella-dominated assemblage (C). This assemblage, which occurs in the upper limestones of each fusulinid cycle records the onset of sea level fall accompanied by a shift to drier conditions and likely increased seawater salinity. The proposed model permits robust interbasinal correlation of the Pennsylvanian successions of the Tethyan realm. Fusulinids of the A and C2 assemblages are the most provincial and therefore the most useful for paleogeographic reconstructions. Specifically, they delineate originally contiguous regions that subsequently were dispersed hundreds to thousands of kilometers, whereas fusulinids of the B assemblage hold the highest potential for global correlation. Extinction at the Moscovian–Kasimovian transition of fusulinid genera of the A and B assemblages, which inhabited predominately cooler and normal salinity (perhaps hyposaline) waters, can be explained by the onset of global warming in the earliest Late Pennsylvanian. Fusulinid assemblages define various types of distribution patterns that differ by tectonic setting of the studied basins suggesting that fusulinid assemblage patterns hold potential for reconstructing the paleogeography and tectonic evolution of Pennsylvanian basins of eastern Laurasia

Exalted dual-scale surface roughening in laser ablated aluminum capped with a transparent thin film: Wetting and anti-icing behavior

Near infrared laser ablation of metals, specifically aluminum, has been systematically applied to generate surface roughness. Very high laser fluences may even lead to a so called “explosive” ablation regime where roughness becomes dramatically enhanced. In the present work we have developed an alternative methodology that, utilizing milder laser irradiation conditions (i.e. laser fluences from 0.37 to 0.72 J/cm²), renders aluminum surfaces with a dual-scale roughness character and Sp parameter values twice or even trice the value found in reference samples. This has been possible for aluminum substrates coated with a highly transparent aluminum oxynitride capping layer. The resulting surfaces, consisting of very rough partially oxidized aluminum with negligible amounts of nitrogen species, resulted highly hydrophobic and depicted long icing delay times as required for anti-icing applications. A correlation has been found between the wetting and anti-icing behaviors, the use of a capping layer and the laser irradiation conditions. To account for this exalted roughening phenomenon, we propose that the transparent capping layer confines the laser energy within the aluminum shallow zones, delays the formation of the plasma plume and produces an enhancement in the aluminum ablation, even at relatively low laser fluences.University of Seville through the VI PPIT-USMCIN/AEI/10.13039/50110001103

Geometric Transition as a Change of Polarization

Taking the results of hep-th/0702110 we study the Dijkgraaf-Vafa open/closed topological string duality by considering the wavefunction behavior of the partition function. We find that the geometric transition associated with the duality can be seen as a change of polarization.Comment: 20 page

Subcategorias reflexivas y correflexivas de la categoria de los espacios topologicos

Often working in certain areas of mathematics and its applications in other branches of science, fortified building objects from universal properties of given objects. These ideas motivate the definitions of coreflective and reflective subcategories, expressing notions improvement, optimization and density. In this article we review the theory of reflective and coreflective subcategories of the category of topological spaces and proposes new methods of construction of these categories in the category of topological spaces and in the category of topological spaces with base pointEs frecuente en el trabajo de ciertas áreas de las matemáticas, y en sus aplicaciones en otras ramas de la ciencia y la ingeniería, construir objetos enriquecidos con propiedades universales, a partir de objetos dados. Estas ideas motivan las definiciones de subcategorías reflexivas y correflexivas, nociones que expresan mejoramiento, optimización y densidad. En este artículo se hace una revisión de la teoría relacionada con las subcategorías reflexivas y correflexivas de la categoría de los espacios topológicos, y a este respecto se proponen nuevos métodos de construcción de dichas categorías en las categorías de los espacios topológicos y en la de los espacios topológicos punteados

A statistical mechanics description of environmental variability in metabolic networks

Many of the chemical reactions that take place within a living cell are irreversible. Due to evolutionary pressures, the number of allowable reactions within these systems are highly constrained and thus the resulting metabolic networks display considerable asymmetry. In this paper, we explore possible evolutionary factors pertaining to the reduced symmetry observed in these networks, and demonstrate the important role environmental variability plays in shaping their structural organization. Interpreting the returnability index as an equilibrium constant for a reaction network in equilibrium with a hypothetical reference system, enables us to quantify the extent to which a metabolic network is in disequilibrium. Further, by introducing a new directed centrality measure via an extension of the subgraph centrality metric to directed networks, we are able to characterise individual metabolites by their participation within metabolic pathways. To demonstrate these ideas, we study 116 metabolic networks of bacteria. In particular, we find that the equilibrium constant for the metabolic networks decreases significantly in-line with variability in bacterial habitats, supporting the view that environmental variability promotes disequilibrium within these biochemical reaction system

Behavior of market prices and analysis of volatility for peach (Prunus persica [L.] Batsch.) produced in Boyaca, Colombia

Páginas 48-62En la actualidad, se encuentran diferentes estudios de caducifolios, y en este caso de durazno en temas como producción, cosecha, poscosecha, mercados. Sin embargo al desarrollar la formulación de los proyectos de inversión, no se conoce el comportamiento del precio de la fruta en los últimos años, en los mercados más representativos del país. Es así como se desarrolló esta investigación centrada en el análisis de los precios de durazno en tres mercados de Colombia: (a) Central de Abastos de Bogotá, (b) Mayorista de Antioquia, Medellín y (c) Reten sur de Tunja, con el objetivo de comprobar si durante el periodo 2006 al 2011, se ha presentado estacionalidad y volatilidad en los precios de mercados, más aun cuando los pequeños productores manifiestan que cada vez este agronegocio es menos rentable y al elaborar nuevos proyectos para invertir en esta especie, se presenta la dificultad en la asignación de los precios de venta. Este aspecto incrementa el riesgo en la toma de decisiones para los productores. El estudio inició desde el análisis de las generalidades de la producción de caducifolios y del durazno, producto que se concentra principalmente en el departamento de Boyacá, Colombia, en agroempresas de tipo minifundistas, de economía campesina. Continuó con la relación de datos de precios por kg/mes, entre el año 2006 y 2011. En los tres mercados, la metodología utilizada fue un análisis exploratorio de los precios por medio del Análisis Espectral Singular, utilizando el Método de Loess. Además, se empleó la metodología de Box y Jenkins. Se logró determinar el comportamiento de tendencia y estacionalidad en los precios del durazno. De otra parte, se identificó que el comportamiento estacional y de tendencia no está presente en los mercados Corabastos de Bogotá y Central mayorista de Antioquia, si se encontró estacionalidad en el mercado de Tunja Cabe resaltar que la volatilidad de los precios no se observó en los tres mercados estudiados, se determinó que el precio promedio actual de duraznos per kg en el mercado de Reten Sur Tunja es de $1.800 (USD 0,60) y de$3.500 (USD 1,17) en los mercados de Bogotá y Medellín.ABSTRACT: At present, there are different studies on deciduous fruits, including the peach, for subjects such as production, harvest, postharvest, and markets. However, for developing the formulation of investment projects, the behavior of fruit prices in the most representative markets of the country are unknown for recent years. This research focused on the analysis of peach prices in three markets in Colombia: (a) Central de Abastos of Bogota, (b) Wholesaler of Antioquia, Medellín and (c) Reten Sur de Tunja, with the objective of verifying whether seasonality and volatility in market prices have occurred during the period 2006 to 2011, even more so when small producers report that agribusiness is becoming less profitable. When new projects are developed to invest in these species, difficulty in the allocation of sales prices is seen. This increases risk in decision making for producers. The study began with the analysis of the generalities of production of deciduous fruits and peaches, a product that is concentrated mainly in the department of Boyacá, Colombia, in agribusinesses of smallholders with a rural economy. It continued with the relation of data of prices per kg/month between the years 2006 and 2011. In the three markets, the methodology used an exploratory analysis of the prices by means of the Singular Spectral Analysis, along with the Loess Method and the Box and Jenkins methodology. It was possible to determine the trend behavior and seasonality in the peach prices. On the other hand, it was observed that a seasonal and trend behavior was not present in the markets of Corabastos of Bogota or Central Wholesale of Antioquia, but seasonality was seen in the market of Tunja. It should be emphasized that the price volatility was not observed in the three markets; it was determined that the current average price per kg of peach fruits in the Reten Sur de Tunja market is $1,800 Colombian Pesos (USD 0.60) and$3,500 Colombian Pesos (USD 1.17) in the Bogotá and Medellin markets, respectivelyBibliografía: páginas 61-62.Artículo revisado por pares

A Comment on Quantum Distribution Functions and the OSV Conjecture

Using the attractor mechanism and the relation between the quantization of $H^{3}(M)$ and topological strings on a Calabi Yau threefold $M$ we define a map from BPS black holes into coherent states. This map allows us to represent the Bekenstein-Hawking-Wald entropy as a quantum distribution function on the phase space $H^{3}(M)$. This distribution function is a mixed Husimi/anti-Husimi distribution corresponding to the different normal ordering prescriptions for the string coupling and deviations of the complex structure moduli. From the integral representation of this distribution function in terms of the Wigner distribution we recover the Ooguri-Strominger-Vafa (OSV) conjecture in the region "at infinity" of the complex structure moduli space. The physical meaning of the OSV corrections are briefly discussed in this limit.Comment: 27 pages. v2:reference and footnote adde

Transcultural adaptation and validation of the ' Hip and Knee ' questionnaire into Spanish

BACKGROUND: The purpose of the present study is to translate and validate the 'Hip and Knee Outcomes Questionnaire', developed in English, into Spanish. The 'Hip and Knee Outcomes Questionnaire is a questionnaire planned to evaluate the impact in quality of life of any problem related to the human musculoskeletal system. 10 scientific associations developed it. METHODS: The questionnaire underwent a validated translation/retro-translation process. Patients undergoing primary knee arthroplasty, before and six months postoperative, tested the final version in Spanish. Psychometric properties of feasibility, reliability, validity and sensitivity to change were assessed. Convergent validity with SF-36 and WOMAC questionnaires was evaluated. RESULTS: 316 patients were included. Feasibility: a high number of missing items in questions 3, 4 and 5 were observed. The number of patients with a missing item was 171 (51.35%) in the preoperative visit and 139 (44.0%) at the postoperative. Internal validity: revision of coefficients in the item-rest correlation recommended removing question 6 during the preoperative visit (coefficient <0.20). Convergent validity: coefficients of correlation with WOMAC and SF-36 scales confirm the questionnaire's validity. Sensitivity to change: statistically significant differences were found between the mean scores of the first visit compared to the postoperative. CONCLUSION: The proposed translation to Spanish of the 'Hip and Knee Questionnaire' is found to be reliable, valid and sensible to changes produced at the clinical practice of patients undergoing primary knee arthroplasty. However, some changes at the completion instructions are recommended. LEVEL OF EVIDENCE: Level I. Prognostic study

EL ESPACIO CONCEBIDO: UN CONCEPTO CLAVE EN LA ENSEÑANZA DE LA GEOGRAFIA

En la didáctica de la geografía se carece de investigaciones relacionadas con las concepciones de los alumnos que fundamenten la orientación didáctica y metodológica en la práctica de la enseñanza. Consciente del problema, el grupo investigador del postgrado de Maestría en Docencia de la Geografía se propuso investigar el concepto de espacio geográfico que manejan los alumnos en Colombia. Inicialmente se estudia la representación espacial de niños de 8 a 10 años, cuyo análisis se presenta en este artículo; posteriormente, y con la colaboración de los licenciados alumnos de la Maestría en Docencia de la Geografía, se examinarán alumnos de otras edades, grados escolares y lugares de residencia. Al divulgar este avance, se pretende establecer contacto con maestros de preescolar, primaria y secundaria que tengan como interés investigativo este mismo objeto: el Espacio Geográfico. Se espera, también, incentivar a quienes quieren sistematizar sus experiencias y prácticas pedagógicas para identificar paulatinamente nuestras características particulares de maestros y educandos y diseñar propuestas metodológicas acordes con tales características