Yield Components in a Signal Grass-Clitoria Mixture Grazed at Different Herbage Allowance

A Signal grass-Clitoria mixture provides good quality forage in the dry tropic of southern Mexico. However, its response in leaf and stem yields to grazing at different daily herbage allowances is not well documented. The objective of this study was to determine available and residual leaf and stem yields in a Signal grass (Brachiaria decumbens)-Clitoria (Clitoria ternatea) mixture grazed at different daily herbage allowance

Numerical Simulation of Electric Currents through Insulating Materials

A numerical simulation of electric currents is carried out through solid dielectrics from a model based on the local polarization. A degradation of material was considered to be produced from one of the electrodes and we simulated it by admitting modifications in the chemical structure of the material, which implies an alteration in the value of the corresponding dipole moments that characterize the material, as well as the concentration of the latest. Different simulations are achieved according to the ratio of the degraded thickness and the temperature

Two-Level Systems and Boson Peak Remain Stable in 110-Million-Year-Old Amber Glass

The two most prominent and ubiquitous features of glasses at low temperatures, namely the presence of tunneling two-level systems and the so-called boson peak in the reduced vibrational density of states, are shown to persist essentially unchanged in highly stabilized glasses, contrary to what was usually envisaged. Specifically, we have measured the specific heat of 110 million-year-old amber samples from El Soplao (Spain), both at very low temperatures and around the glass transition Tg. In particular, the amount of two-level systems, assessed at the lowest temperatures, was surprisingly found to be exactly the same for the pristine hyperaged amber as for the, subsequently, partially and fully rejuvenated samples.Comment: 22 pages, 9 figures, 2 tables (including Supplementary Material

Ballistic resistivity in aluminum nanocontacts

One of the major industrial challenges is to profit from some fascinating physical features present at the nanoscale. The production of dissipationless nanoswitches (or nanocontacts) is one of such attractive applications. Nevertheless, the lack of knowledge of the real efficiency of electronic ballistic/non dissipative transport limits future innovations. For multi-valent metallic nanosystems -where several transport channels per atom are involved- the only experimental technique available for statistical transport characterization is the conductance histogram. Unfortunately its interpretation is difficult because transport and mechanical properties are intrinsically interlaced. We perform a representative series of semiclassical molecular dynamics simulations of aluminum nanocontact breakages, coupled to full quantum conductance calculations, and put in evidence a linear relationship between the conductance and the contact minimum cross-section for the geometrically favored aluminum nanocontact configurations. Valid in a broad range of conductance values, such relation allows the definition of a transport parameter for nanomaterials, that represents the novel concept of ballistic resistivity

KBE Application for the Design and Manufacture of HSM Fixtures

The design of machining fixtures for aeronautical parts is strongly based in the knowledge of the fixture designer, and it comprises certain repetitive tasks. An analysis of the design process allows us to state its suitability for developing Knowledge Based Engineering (KBE) applications in order to capture the knowledge, and to systematize and automate the designs.This work justifies the importance of fixtures for High Speed Milling (HSM), and explains the development of a KBE application to automate the design and manufacturing of such elements. The application is the outcome of a project carried out in collaboration with the company EADS.In the development process, a specific methodology was used in order to represent the knowledge in a semi-structured way and to document the information needed to define the system. The developed KBE application is independent of the parts design system. This makes it necessary to use an interface to input the part geometry into the KBE application, where it is analyzed in order to extract the relevant information for the fixture design process. The results obtained from the application come in three different ways: raw material drawings, fixture 3D solid models, and text files (Bill Of Materials – BOM, and Numerical Control – NC programs). All the results are exported to other applications for use in other tasks. The designer interacts with the application through an ad hoc interface, where he is asked to select or input some data and where the results are also visualized. The prototype KBE application has been carried out in the ICAD development environment and the main interface is with the CAD/CAM system CATIA V4.

Towards a Programming Language in Cellular Computing

AbstractSeveral solutions to hard numerical problems using P systems have been presented recently, and strong similarities in their designs have been noticed. In this paper we present a new solution, to the Partition problem, via a family of deterministic P systems with active membranes using 2-division. Then, we intend to show that the idea of a cellular programming language is possible (at least for some relevant family of NP-complete problems), indicating some “subroutines” that can be used in a variety of situations and therefore could be useful for designing solutions for new problems in the future

A P-Lingua based simulator for tissue P systems

AbstractInvestigations within the field of tissue-like P systems are being conducted, on one hand studying their computational efficiency, and on the other hand exploring the possibilities to use them as a computational modelling framework to biological phenomena.In both cases it is necessary to develop software that provides simulation tools (simulators) for the existing variety of tissue P systems. Such simulators allow us to carry on computations of solutions to computationally hard problems on certain (small) instances. Moreover, they also provide a way to verify tissue-like models for real biological processes, by means of experimental data.The paper presents an extension of P-Lingua (a specification language intended to become a standard for software devoted to P systems), in order to cover the class of tissue-like P systems, that were not considered in the previous release. This extension involves on one hand defining the syntax to be used, and on the other hand introducing a new built-in simulation algorithm that has been added to the core library of P-Lingua

Pattern of injuries in beach volleyball at the spanish national university championship

Este artículo pretende establecer y determinar las lesiones más frecuentes en jugadores de vóley playa universitarios a través de una muestra de 33 participantes en el Campeonato de España Universitario. Para estudiar las lesiones, se realizó una entrevista personal mediante un cuestionario validado. Los resultados mostraron que la región corporal con mayor incidencia lesiva fue el tobillo (33,3%), seguido de los dedos de la mano (18,5%), las rodillas (13,0%), los hombros (11,1%) y la espalda (5,6%). Además también se obtuvieron datos sobre el momento de la lesión (competición o entrenamiento), su origen (impacto o sobreuso) y característica de la lesión (nueva lesión o repetida). El tratamiento de los datos para el establecimiento de las diferencias significativas se realizó a través de la prueba estadística Chi-Cuadrado. Los resultados establecen un patrón de lesiones diferente al que se produce en vóley playa profesional, probablemente como consecuencia directa del nivel, horas de entrenamiento y exigencia del juegoThe aim of this paper is to study the most common injuries in university beach volleyball players. The sample consisted in 33 athletes participating in the University Spanish Championship. Injuries were assessed by means of personal interviews and a validated questionnaire. Results show that the body region with the highest incidence was the ankle (33%), followed by the fingers (18.5%), knees (13.0%), shoulders (11.1%) and back (5.6%). Also, information on the moment of injury (competition or training), origin (impact or overuse) and characteristic of the injury (new or recurrent injury). Statistical processing of data for establishing significant differences was performed using the Chi-square test. Results showed a harmful effect, which differs from that of professional volley players, probably as a result of the level, hours of training and requirements of the gam