2,848 research outputs found

    The Dirichlet Obstruction in AdS/CFT

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    The obstruction for a perturbative reconstruction of the five-dimensional bulk metric starting from the four-dimensional metric at the boundary,that is, the Dirichlet problem, is computed in dimensions 6d106\leq d\leq 10 and some comments are made on its general structure and, in particular, on its relationship with the conformal anomaly, which we compute in dimension d=8d=8.Comment: 13 pages, references added (this paper supersedes hep-th/0206140, "A Note on the Bach Tensor in AdS/CFT", which has been withdrawn

    Obtaining preforms by additive fused deposition modelling (FDM) extrusion technology for the manufacture of high-performance composites

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    The composites industry is present in practically all industrial sectors with an annual growth rate of 5%. Its contribution to the priority "light-weighting" driver in the transport sector is key. The efficiency of the industry is made possible by the evolution of manufacturing processes that also improve the performance of the products obtained. For example, out-of-autoclave (OOA) processes can obtain high-performance composites such as those obtained by the autoclave process at lower costs. A key aspect in the development of this type of process is the preforming of continuous fibre reinforcements, which can achieve high fibre percentages while facilitating processing. Manufacturing these preforms currently requires multiple steps, equipment and tooling. TECNALIA's work developing the ADDICOMP technology, an alternative preform manufacturing method using an additive process based on Fused Deposition Modelling (FDM) is detailed in this article. This development is patented by Tecnalia and was conducted in 2 phases: (a) development of continuous fibre filaments coated with polymeric material and printable by FDM and (b) fine-tuning of FDM technology to print filaments with a very high content of continuous fibre

    Rudiments of Holography

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    An elementary introduction to Maldacena's AdS/CFT correspondence is given, with some emphasis in the Fefferman-Graham construction. This is based on lectures given by one of us (E.A.) at the Universidad Autonoma de Madrid.Comment: 60 pages, additional misprints corrected, references adde

    Ewe Daily-Weight Gain Grazing \u3ci\u3eLeucaena leucocephala-Megathyrsus maximus\u3c/i\u3e CV Mombasa Silvopastoral System and Tropical Native Unimproved Range

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    Silvopastoral systems are a viable option to increase livestock productivity, The silvopastoral arrangement of Leucaena leucocephala associated with Megathyrsus maximus CV Mombasa (LMS) is successfully cultivated in tropical environments.. The objective of the study was to determine ewe daily-weight gain grazing LMS and a tropical unimproved native range. Two LMS were tested: high and low leucaena densities, 4700 and 2383 plants/ha, respectively. Grazing was rotational, lasted 150 d (rainy season) at equivalent stocking rate of 59 ewes/ha/150 d. Experimental design was a completely random design with three replications, the experimental unit was a 192 m2 plot. Variables measured on plots were amount (dry matter basis), in vitro dry matter digestibility (IVDMD), and crude protein (CP) of forage on-offer, from mixed samples herbaceous and tree fodder. Weight and serum concentrations of Ca, P, K, Mg, Na, Zn, Cu, and Fe were measured in ewes, daily weight gain was calculated. On average forage on-offer and IVDMD concentration were 50 and 15% higher (p \u3c 0.05) in LMS than in native range, respectively, with no difference between LMS. CP concentration was 25% higher (p \u3c 0.05) in native range than both LMS, with no difference between them. LMS’s showed no difference (p \u3e 0.05) between them on ewe daily weight gain, on average 59.2 g, and were higher than native range where ewes showed a mean daily weight loss of 14.8 g. Serum concentrations of the 8 minerals measured were similar (p \u3e 0.05) across all ewes regardless the treatments. It was concluded that the Leucaena leucocephala-Megathyrsus maximus CV Mombasa silvopastoral system is an option to improve livestock productivity compared with unimproved native range due to higher forage on-offer

    Ewe Daily-Weight Gain Grazing \u3ci\u3eLeucaena leucocephala-Megathyrsus maximus\u3c/i\u3e CV Mombasa Silvopastoral System and Tropical Native Unimproved Range

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    Silvopastoral systems are a viable option to increase livestock productivity, The silvopastoral arrangement of Leucaena leucocephala associated with Megathyrsus maximus CV Mombasa (LMS) is successfully cultivated in tropical environments.. The objective of the study was to determine ewe daily-weight gain grazing LMS and a tropical unimproved native range. Two LMS were tested: high and low leucaena densities, 4700 and 2383 plants/ha, respectively. Grazing was rotational, lasted 150 d (rainy season) at equivalent stocking rate of 59 ewes/ha/150 d. Experimental design was a completely random design with three replications, the experimental unit was a 192 m2 plot. Variables measured on plots were amount (dry matter basis), in vitro dry matter digestibility (IVDMD), and crude protein (CP) of forage on-offer, from mixed samples herbaceous and tree fodder. Weight and serum concentrations of Ca, P, K, Mg, Na, Zn, Cu, and Fe were measured in ewes, daily weight gain was calculated. On average forage on-offer and IVDMD concentration were 50 and 15% higher (p \u3c 0.05) in LMS than in native range, respectively, with no difference between LMS. CP concentration was 25% higher (p \u3c 0.05) in native range than both LMS, with no difference between them. LMS’s showed no difference (p \u3e 0.05) between them on ewe daily weight gain, on average 59.2 g, and were higher than native range where ewes showed a mean daily weight loss of 14.8 g. Serum concentrations of the 8 minerals measured were similar (p \u3e 0.05) across all ewes regardless the treatments. It was concluded that the Leucaena leucocephala-Megathyrsus maximus CV Mombasa silvopastoral system is an option to improve livestock productivity compared with unimproved native range due to higher forage on-offer

    Effect of the non-stationarity of rainfall events on the design of hydraulic structures for runoff management and its applications to a case study at Gordo Creek watershed in Cartagena de Indias, Colombia

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    The 24-h maximum rainfall (P 24h-max ) observations recorded at the synoptic weather station of Rafael Núñez airport (Cartagena de Indias, Colombia) were analyzed, and a linear increasing trend over time was identified. It was also noticed that the occurrence of the rainfall value (over the years of record) for a return period of 10 years under stationary conditions (148.1 mm) increased, which evidences a change in rainfall patterns. In these cases, the typical stationary frequency analysis is unable to capture such a change. So, in order to further evaluate rainfall observations, frequency analyses of P 24h-max for stationary and non-stationary conditions were carried out (by using the generalized extreme value distribution). The goodness-of-fit test of Akaike Information Criterion (AIC), with values of 753.3721 and 747.5103 for stationary and non-stationary conditions respectively, showed that the latter best depicts the increasing rainfall pattern. Values of rainfall were later estimated for different return periods (2, 5, 10, 25, 50, and 100 years) to quantify the increase (non-stationary versus stationary condition), which ranged 6% to 12% for return periods from 5 years to 100 years, and 44% for a 2-year return period. The effect of these findings were tested in the Gordo creek watershed by first calculating the resulting direct surface runoff (DSR) for various return periods, and then modeling the hydraulic behavior of the downstream area (composed of a 178.5-m creek's reach and an existing box-culvert located at the watershed outlet) that undergoes flooding events every year. The resulting DSR increase oscillated between 8% and 19% for return periods from 5 to 100 years, and 77% for a 2-year return period when the non-stationary and stationary scenarios were compared. The results of this study shed light upon to the precautions that designers should take when selecting a design, based upon rainfall observed, as it may result in an underestimation of both the direct surface runoff and the size of the hydraulic structures for runoff and flood management throughout the city. © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license

    An overview on the Prus-Szczepanik condition

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    In 2005 Prus and Sczcepanik introduced a large class of Banach spaces with the fixed point property for nonexpansive mappings. We say that this class satisfies the PSz condition. Checking that a given Banach space belongs to this class is not an easy task. Here we study the relationship between the PSz condition and other well-known geometrical properties of Banach spaces, and we give easier sufficient conditions for a Banach space to satisfy it.Consejo Nacional de Ciencia y Tecnologia (México)Ministerio de Economía y Competitivida
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