846 research outputs found

    Assessment of the effect of a new technique for laparoscopic partial closure of the inguinal canal on sperm production and testicular perfusion in stallions

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    In order to simplify other laparoscopic techniques, a new standing laparoscopic technique for partial closure of inguinal canal (PCIC) has been developed. This technique uses a new anchoring device and can be performed without advanced laparoscopic skills. The aim of this study was to develop a prior evaluation of the effects of this new technique on the stallion reproductive capacity, assessing the sperm production and testicular perfusion. Standing laparoscopic PCIC was performed unilaterally in 8 experimental stallions without evidence of inguinal hernia, using the contralateral canal and testicle as control

    Proposal of a production and management index (PMI) for tilapia farms

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    Tilapia is one of the most important species in aquaculture; however, there is no available index to show the performance of a production unit. It is desirable to assess the productivity using indexes, such as the production and management index for shrimps and the European production efficacy factor for broilers. These indexes are based on data production: growth, survival, and feed conversion of a full production cycle. Taking into account these parameters, we propose a production and management index (PMI) for tilapia that is applicable for a specific period of the production cycle. For the construction and validation of the PMI we have used production data from 8, 614 monthly records of 2 tilapia farms in Huila Department (Colombia), and because of the complexity of tilapia management, different anomalous situations have been detected and then defined as exceptions. As a result, 419 records were considered extreme values because 1 or more exceptions were met. The value of the PMI varies from 0 (the worst situation) to 3.55, which reflects high variability. We have constructed a PMI for tilapia as the product of 3 elements to obtain a positive value index. Instead of classic parameters, we had to calculate an adapted version of them: the relative average daily growth, the survival (as a complementary value of the estimated monthly mortality), and a feed conversion ratio index. To assess the utility of the PMI, some comparisons were performed using records from black and red tilapia. We observed significant differences depending on tilapia strain (PMIblack = 1.0248 vs. PMIred = 1.1661; P < 0.001), age (better values for small fish), and season (PMIrainy = 1.0847 vs. PMIdry = 1.1011; P = 0.026). According to these results, we can conclude that the PMI could be a useful tool for tilapia farmers, despite the complexity of the calculation

    New derivation of soliton solutions to the AKNS2_2 system via dressing transformation methods

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    We consider certain boundary conditions supporting soliton solutions in the generalized non-linear Schr\"{o}dinger equation (AKNSr_r)\,(r=1,2r=1,2). Using the dressing transformation (DT) method and the related tau functions we study the AKNSr_{r} system for the vanishing, (constant) non-vanishing and the mixed boundary conditions, and their associated bright, dark, and bright-dark N-soliton solutions, respectively. Moreover, we introduce a modified DT related to the dressing group in order to consider the free field boundary condition and derive generalized N-dark-dark solitons. As a reduced submodel of the AKNSr_r system we study the properties of the focusing, defocusing and mixed focusing-defocusing versions of the so-called coupled non-linear Schr\"{o}dinger equation (rr-CNLS), which has recently been considered in many physical applications. We have shown that two-dark-dark-soliton bound states exist in the AKNS2_2 system, and three- and higher-dark-dark-soliton bound states can not exist. The AKNSr_r\,(r3r\geq 3) extension is briefly discussed in this approach. The properties and calculations of some matrix elements using level one vertex operators are outlined.Comment: 34 pages, 3 figures. Extended version of arXiv:1110.3108[nlin.SI], to appear in J. Phys. A: Math. Theo

    El origen geológico, galaico, del ejemplar de Marabiu (Teverga, Asturias) y consideraciones culturales sobre los útiles-arma, calificados de "hachas nórdicas", del Noroeste ibérico

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    The physical analysis of a perforated item from Asturias shows that its only presence in the Cantabric region is due to an import from Galicia (cianites of Touro, near Santiago de Compostela). The concentration of these tool-weapons in barrows of the III millenium in Galicia is a unique focus in the Iberian peninsula of a very well known phenomenon in Europe. In this article, geographic, economic and cultural arguments are offered, justifiyng the peculiar presence of these sceptres or status symbols and of their local character, although they remind us of types in the continental NW, so that the Galician perforated tools are classified as ''northern battle-axes".El análisis físico de un ejemplar perforado del centro de Asturias (Marabiu) prueba que su solitaria presencia en la Región Cantábrica se debe a una importación desde Galicia (cianitas deTouro, al E de Santiago de Compostela). La concentración de estos útiles-arma en túmulos del III milenio en Galicia (Coruña y O de Lugo) dibuja el foco único en la Península Ibérica de un fenómeno bien conocido en Europa. En el artículo se ofrecen argumentos geográficos, económicos y culturales justificativos de la presencia singular de estos "cetros" o símbolos de estatus, de su carácter local aunque se aprecien resonancias de tipos de NO continental, lo que hizo que se calificara a los perforados gallegos de "hachas de combate nórdicas"

    On Non-Linear Actions for Massive Gravity

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    In this work we present a systematic construction of the potentially ghost-free non-linear massive gravity actions. The most general action can be regarded as a 2-parameter deformation of a minimal massive action. Further extensions vanish in 4 dimensions. The general mass term is constructed in terms of a "deformed" determinant from which this property can clearly be seen. In addition, our formulation identifies non-dynamical terms that appear in previous constructions and which do not contribute to the equations of motion. We elaborate on the formal structure of these theories as well as some of their implications.Comment: v3: 22 pages, minor comments added, version to appear in JHE

    Tools for Deconstructing Gauge Theories in AdS5

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    We employ analytical methods to study deconstruction of 5D gauge theories in the AdS5 background. We demonstrate that using the so-called q-Bessel functions allows a quantitative analysis of the deconstructed setup. Our study clarifies the relation of deconstruction with 5D warped theories.Comment: 30 pages; v2: several refinements, references adde

    Effective description of general extensions of the Standard Model: the complete tree-level dictionary

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    We thank Nuria Rius and Arcadi Santamaria for an interesting discussion that motivated this work. We also thank Paco del Águila and Toni Pich for useful comments.We compute all the tree-level contributions to the Wilson coefficients of the dimension-six Standard-Model effective theory in ultraviolet completions with general scalar, spinor and vector feld content and arbitrary interactions. No assumption about the renormalizability of the high-energy theory is made. This provides a complete ultraviolet/ infrared dictionary at the classical level, which can be used to study the low-energy implications of any model of interest, and also to look for explicit completions consistent with low-energy dataThe work of J.C.C., M.P.V. and J.S. has been supported by the Spanish MICINN project FPA2013- 47836-C3-2-P, the MINECO project FPA2016-78220-C3-1-P (Fondos FEDER) and the Junta de Andalucía grant FQM101. The work of J.C.C. has also been supported by the Spanish MECD grant FPU14. The work of M.P.V. and J.S. has also been supported by the European Commission through the contract PITN-GA-2012-316704 (HIGGSTOOLS). J.C.C. is grateful for the hospitality of the Dipartimento di Fisica e Astronomia \Galileo Galilei" of the University of Padova during part of this work. J.S. would like to thank the Mainz Institute for Theoretical Physics (MITP) for its hospitality and partial support during the completion of this work

    Metal Removal from Contaminated Soils Trough Bioleaching with Oxidizing Bacteria and Rhamnolipid Biosurfactants

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    The use of surfactants as a method for solubilization and removal of heavy metal contamination from soil has been reported before. Biosurfactants produced by some microorganisms are able to modify the surface of various metals and aggregate on interphases favoring the metal separation process from contaminated environments. We evaluated the feasibility of enhancing the removal of metal ions from mineral waste/contaminated soils using alternate cycles of treatment with rhamnolipid biosurfactants and bioleaching with a mixed bacterial culture of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans. Bioleaching alone removed 50% Zn and 19% Fe. When rhamnolipids were used at low concentration (0.4 mg/mL), 11% Fe and 25% Zn were removed, while at 1 mg/mL 19% Fe and 52% Zn removal were achieved. When using a cyclic treatment combining bioleaching and biosurfactants, metal removal reached up to 36% for Fe and 63% to 70% for Zn

    Comparison of autologous bone marrow and adipose tissue derived mesenchymal stem cells, and platelet rich plasma, for treating surgically induced lesions of the equine superficial digital flexor tendon

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    Several therapies have been investigated for equine tendinopathies, but satisfactory long term results have not been achieved consistently and a better understanding of the healing mechanism elicited by regenerative therapies is needed. The aim of this study was to assess the separate effects of autologous bone marrow (BM) and adipose tissue (AT) derived mesenchymal stem cells (MSCs), and platelet rich plasma (PRP), for treating lesions induced in the superficial digital flexor tendon (SDFT) of horses. Lesions were created surgically in both SDFTs of the forelimbs of 12 horses and were treated with BM-MSCs (six tendons), AT-MSCs (six tendons) or PRP (six tendons). The remaining six tendons received lactated Ringer''s solution as control. Serial ultrasound assessment was performed prior to treatment and at 2, 6, 10, 20 and 45 weeks post-treatment. At 45 weeks, histopathology and gene expression analyses were performed. At week 6, the ultrasound echogenicity score in tendons treated with BM-MSCs suggested earlier improvement, whilst all treatment groups reached the same level at week 10, which was superior to the control group. Collagen orientation scores on histological examination suggested a better outcome in treated tendons. Gene expression was indicative of better tissue regeneration after all treatments, especially for BM-MSCs, as suggested by upregulation of collagen type I, decorin, tenascin and matrix metalloproteinase III mRNA. Considering all findings, a clear beneficial effect was elicited by all treatments compared with the control group. Although differences between treatments were relatively small, BM-MSCs resulted in a better outcome than PRP and AT-MSCs

    The scope of language contact as a constraint factor in language change: The periphrasis haber de plus infinitive in a corpus of language immediacy in modern Spanish

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    In this work an empirical study grounded in the principles and methods of the comparative variationist framework is conducted to measure the scope of language contact as a factor constraining some potentially diverging uses of a Spanish verbal periphrasis that has undergone a sharp decline over the last century (haber de plus infinitive). The analysis is based on three independent samples of text that correspond to three dialectal areas of peninsular Spanish (monolingual zones, Catalan-speaking linguistic territories and the north-western linguistic area). These samples, extracted from a corpus made up of texts of communicative immediacy from the 19th and the first half of the 20th centuries, confirm the existence of a certain linguistic convergence in the expressive habits of the speakers in the bilingual communities. In each region, however, the outcomes are different, due to parallel differences in the structural position of the periphrasis in each language. However, a thorough analysis of the variable context that surrounds the periphrasis shows that the observed differences do not affect the essence of the underlying grammar of this variant, whose decline (which favours tener que plus infinitive and becomes faster as the 20th century advances) is constrained by identical linguistic and extralinguistic conditioning factors in all the dialectal areas
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