Extended analytic QCD model with perturbative QCD behavior at high momenta

In contrast to perturbative QCD, the analytic QCD models have running coupling whose analytic properties correctly mirror those of spacelike observables. The discontinuity (spectral) function of such running coupling is expected to agree with the perturbative case at large timelike momenta; however, at low timelike momenta it is not known. In the latter regime, we parametrize the unknown behavior of the spectral function as a sum of (two) delta functions; while the onset of the perturbative behavior of the spectral function is set to be 1.0-1.5 GeV. This is in close analogy with the "minimal hadronic ansatz" used in the literature for modeling spectral functions of correlators. For the running coupling itself, we impose the condition that it basically merges with the perturbative coupling at high spacelike momenta. In addition, we require that the well-measured nonstrange semihadronic (V+A) tau decay ratio value be reproduced by the model. We thus obtain a QCD framework which is basically indistinguishable from perturbative QCD at high momenta (Q > 1 GeV), and at low momenta it respects the basic analyticity properties of spacelike observables as dictated by the general principles of the local quantum field theories.Comment: 15 pages, 6 figures; in v2 Sec.IV is extended after Eq.(48) and refs.[51-52] added; v2 published in Phys.Rev.D85,114043(2012

Dating volcanic ash and pumice stones from volcano El Misti, Peru, by thermoluminescence

El Misti is one of active volcanos in Peru, and known because it is located close to an important city of Arequipa, at about 17 km. There has been in the past several eruptions and the volcano is covered with lava, ash, etc. from such eruptions. The edifice is composed of a stratotocone called Misti 1, two stratocones designated Misti 2 and Misti 3 and a summit cone Misti 4. In this work samples from Misti 3 have been collected for TL dating. In the past charcol has been used for radiocarbon measurements and found age varying from 25000 to 35000 years. The TL dating produces ages between 28700 and 32300 years

Influence of Penile Spicules of Covies(Cavia porcellus)on their Sexual Behavior, Fertility and Sperm Quality

This research took place in canton Cuenca, province of Azuay, Ecuador, located on UTM 717386 x 9675751, 2 714 meters above sea level, with a mean temperature of 14°C. The study determined the influence of penile spicules on sexual behavior, fertility and sperm quality parameters in cavies (Cavia porcellus), raised on the Ecuadoran highlands. A number of 5 whole males (with penile spicules), and other 5 males with their spicules removedwere included in the study, along with 40 nulliparous females, type A, pelage type 1. The pregnancy percentage of females that copulated with extirpated males decreased 65% in relation to the control group (P<0.05). However, the sexual behavior pattern and sperm quality of the two groups in the study were similar (P>0.05). Therefore, the study concluded that extirpation of the penile spicules has effects on fertility, but not on sexual behavior and sperm quality

Open-atmosphere structural depth profiling of multilayer samples of photovoltaic interest using laser-induced plasma spectrometry

The present work aims to assess Laser-Induced Plasma Spectrometry (LIPS) as a tool for the characterization of photovoltaic materials. Despite being a well-established technique with applications to many scientific and industrial fields, so far LIPS is little known to the photovoltaic scientific community. The technique allows the rapid characterization of layered samples without sample preparation, in open atmosphere and in real time. In this paper, we assess LIPS ability for the determination of elements that are difficult to analyze by other broadly used techniques, or for producing analytical information from very low-concentration elements. The results of the LIPS characterization of two different samples are presented: 1) a 90 nm, Al-doped ZnO layer deposited on a Si substrate by RF sputtering and 2) a Te-doped GaInP layer grown on GaAs by Metalorganic Vapor Phase Epitaxy. For both cases, the depth profile of the constituent and dopant elements is reported along with details of the experimental setup and the optimization of key parameters. It is remarkable that the longest time of analysis was ∼10 s, what, in conjunction with the other characteristics mentioned, makes of LIPS an appealing technique for rapid screening or quality control whether at the lab or at the production line

Range extension to Santo Domingo de los Tsáchilas province and revised distribution of Platyrrhinus chocoensis (Phyllostomidae: Chiroptera) in western Ecuador

We report the first record of the Choco broad-nosed bat (Plathyrrhinus chocoensis Alberico & Velazco, 1991) in Santo Domingo de los Tsáchilas province in northwestern Ecuador. This voucher specimen represents the southernmost record of the species and expands its distribution ca. 120 km south. The animal was caught at a farm, specifically in a live fence consisting of several tree species. Preservation of bat species occurring in agricultural landscapes requires local policies and environmental education

Thermoluminescence and defect centers in synthetic diopside

MgCaSi2O6 polycrystal was synthesized by the devitrification method. The dosimetric characteristics by TL of this prepared polycrystal was investigated. This material exhibits TL peaks at 115, 160, 210, 260 and 280 °C. The dosimetric peak occurs at 260 °C with a well defined glow curve structure. This peak shows a linear dose response. Electron paramagnetic resonance (EPR) studies have been carried out to identify the defect centers responsible for the TL peaks. Two defect centers in the region of g = 2.0 are found. One of the centers (center I) with a g factor equal to 2.0085 is identified as O− -ion and relates with the observed high temperature 250 and 300 °C TL peaks. Additional defect centers with g = 2.0012 (center II) and 1.982 (center III) are due to F+- centers (electron trapped at an oxygen vacancy). Center II and III correlate with the TL peaks at 160 °C and 106 °C, respectively.Campus Arequip

Covariables Ambientales que Definen los Principales Grupos de Suelo en México

La variabilidad de los suelos depende de la interacción de covariables ambientales que intervienen en su formación. En México, se registran 25 grupos de suelo de los 32 que incluye la Base Referencial Mundial (BRM). Este estudio identifica el orden de importancia de 11 covariables ambientales, utilizando el modelo no paramétrico basado en un algoritmo de aprendizaje automático supervisado denominado random forest, el cual caracteriza 19 grupos de suelo que incluyen el 99.2% del territorio nacional. Las covariables que se incluyeron fueron, curvatura, densidad de drenaje, distancia al cauce más cercano, geología, índice de aridez, índice de humedad topográfica, índice de posición topográfica, índice de vegetación de diferencia normalizada (NDVI), radiación, rugosidad y temperatura. Los resultados mostraron un total de 100 árboles de clasificación, con una precisión global de 81.83% del modelo a través de random forest y un valor de Kappa de 0.80, expresado como muy bueno. La precisión de disminución promedio mostró que, las cinco covariables analizadas más importantes que clasifican los 19 grupos de suelo son, índice de posición topográfica, índice de aridez, curvatura, radiación y densidad de drenaje

A Secreted NlpC/P60 Endopeptidase from Photobacterium damselae subsp. piscicida Cleaves the Peptidoglycan of Potentially Competing Bacteria

Peptidoglycan (PG) is a major component of the bacterial cell wall, forming a mesh-like structure enwrapping the bacteria that is essential for maintaining structural integrity and providing support for anchoring other components of the cell envelope. PG biogenesis is highly dynamic and requires multiple enzymes, including several hydrolases that cleave glycosidic or amide bonds in the PG. This work describes the structural and functional characterization of an NlpC/P60-contain-ing peptidase from Photobacterium damselae subsp. piscicida (Phdp), a Gram-negative bacterium that causes high mortality of warm-water marine fish with great impact for the aquaculture industry. PnpA (Photobacterium NlpC-like protein A) has a four-domain structure with a hydrophobic and narrow access to the catalytic center and specificity for the γ-D-glutamyl-meso-diaminopimelic acid bond. However, PnpA does not cleave the PG of Phdp or PG of several Gram-negative and Gram-positive bacterial species. Interestingly, it is secreted by the Phdp type II secretion system and degrades the PG of Vibrio anguillarum and Vibrio vulnificus. This suggests that PnpA is used by Phdp to gain an advantage over bacteria that compete for the same resources or to obtain nutrients in nutrient-scarce environments. Comparison of the muropeptide composition of PG susceptible and resistant to the catalytic activity of PnpA showed that the global content of muropeptides is similar, suggesting that susceptibility to PnpA is determined by the three-dimensional organization of the muropeptides in the PG. IMPORTANCE Peptidoglycan (PG) is a major component of the bacterial cell wall formed by long chains of two alternating sugars interconnected by short peptides, generating a mesh-like structure that enwraps the bacterial cell. Although PG provides structural integrity and support for anchoring other components of the cell envelope, it is constantly being remodeled through the action of specific enzymes that cleave or join its components. Here, it is shown that Photobacterium damselae subsp. piscicida, a bacterium that causes high mortality in warm-water marine fish, produces PnpA, an enzyme that is secreted into the environment and is able to cleave the PG of potentially competing bacteria, either to gain a competitive advantage and/or to obtain nutrients. The specificity of PnpA for the PG of some bacteria and its inability to cleave others may be explained by differences in the structure of the PG mesh and not by different muropeptide composition.Europeu de Desenvolvimento Regional (FEDER) funds through the COMPETE 2020 Operacional Program for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior and Fundação para a Ciência e a Tecnologia (FCT), I.P., within the scope of the Norma Transitória - DL57/2016/CP1355/CT0010. This work had also support from the State Agency for Research (AEI) of Spain cofunded by the FEDER Program from the European Union (grants AGL2016-79738-R and BIO2016-77639-P

Agua virtual en un marco insumo-producto para la cuenca del valle de México

La cuenca del valle de México (CVM) se ubica en la región central de México, genera la cuarta parte de la producción total nacional y registra la mayor sobreexplotación de sus acuíferos en el país. Este artículo introduce la metodología para estimar los multiplicadores de agua virtual (MAV) de cada actividad económica de la cuenca a partir de la matriz insumo-producto de la cuenca del valle de México 2008. Los MAV contabilizan el agua virtual involucrada en las actividades económicas dentro de la región, con el resto de la economía de México y el mundo. Los resultados identifican las actividades económicas de baja y alta intensidad en el uso del agua que predominan en la cuenca. Asimismo, haciendo el balance entre exportaciones e importaciones de agua virtual en la CVM, se concluye que se importan bienes con alto contenido de agua y se exportan bienes con bajo contenido del recurso. Dicho comportamiento describe a la cuenca como una región importadora neta de agua virtual, lo cual es una característica positiva que ayuda a compensar el estrés hídrico que sufre la cuenca. Este hallazgo parece confirmar el teorema de Heckscher-Ohlin del comercio internacional, sugiriendo la racionalidad económica de una región que enfrenta el mayor estrés hídrico del país