Protective circuit of the spark gap type

Spark gap type protective circuit for fast sensing and removal of overvoltage condition

Trisphere spark gap actuates overvoltage relay

Trisphere spark gap and high voltage relay provides a positive, fast response, high current capacity device that will sense an overvoltage condition and remove power from the circuit before insulation breakdown. When an overvoltage occurs, the spark gap breaks down and conducts an actuating current to the relay which removes power from the circuit

WKB formalism and a lower limit for the energy eigenstates of bound states for some potentials

In the present work the conditions appearing in the WKB approximation formalism of quantum mechanics are analyzed. It is shown that, in general, a careful definition of an approximation method requires the introduction of two length parameters, one of them always considered in the text books on quantum mechanics, whereas the second one is usually neglected. Afterwards we define a particular family of potentials and prove, resorting to the aforementioned length parameters, that we may find an energy which is a lower bound to the ground energy of the system. The idea is applied to the case of a harmonic oscillator and also to a particle freely falling in a homogeneous gravitational field, and in both cases the consistency of our method is corroborated. This approach, together with the Rayleigh--Ritz formalism, allows us to define an energy interval in which the ground energy of any potential, belonging to our family, must lie.Comment: Accepted in Modern Physics Letters

Saturday Morning Television Advertisements Aired on English and Spanish Language Networks along the Texas-Mexico Border

Objectives: The aim of this content analysis study is to characterize the TV advertisements aired to an at-risk child population along the Texas-Mexico border. Methods: We characterized the early Saturday morning TV advertisements aired by three broadcast network categories (U.S. English language, U.S. Spanish language, and Mexican Spanish language) in Spring 2010. The number, type (food related vs. non-food related), target audience, and persuasion tactics used were recorded. Advertised foods, based on nutrition content, were categorized as meeting or not meeting current dietary guidelines. Results: Most commercials were non-food related (82.7%, 397 of 480). The majority of the prepared foods (e.g., cereals, snacks, and drinks) advertised did not meet the current U.S. Dietary Guidelines. Additionally, nutrition content information was not available for many of the foods advertised on the Mexican Spanish language broadcast network category. Conclusions: For U.S. children at risk for obesity along the Texas-Mexico border exposure to TV food advertisements may result in the continuation of sedentary behavior as well as an increased consumption of foods of poor nutritional quality. An international regulatory effort to monitor and enforce the reduction of child-oriented food advertising is needed. Editors\u27 Note: This article was submitted in response to the first issue of the Journal of Applied Research on Children: Latino Children

Continuous distribution of frequencies and deformed dispersion relations

The possibilities that, in the realm of the detection of the so--called deformed dispersion relation, a light source with a continuous distribution of frequencies offers is discussed. It will be proved that the presence of finite coherence length entails the emergence of a new term in the interference pattern. This is a novel trait, which renders a new possibility in the quest for bounds associated with these deformed dispersion relations.Comment: Accepted in Classical and Quantum Gravit

Leibniz algebras with associated Lie algebras sl_2\dot{+} R (dim R=2)

From the theory of finite dimensional Lie algebras it is known that every finite dimensional Lie algebra is decomposed into a semidirect sum of semisimple subalgebra and solvable radical. Moreover, due to work of Mal'cev the study of solvable Lie algebras is reduced to the study of nilpotent ones. For the finite dimensional Leibniz algebras the analogues of the mentioned results are not proved yet. In order to get some idea how to establish the results we examine the Leibniz algebra for which the quotient algebra with respect to the ideal generated by squares elements of the algebra (denoted by $I$) is a semidirect sum of semisimple Lie algebra and the maximal solvable ideal. In this paper the class of complex Leibniz algebras, for which quotient algebras by the ideal $I$ are isomorphic to the semidirect sum of the algebra $sl_2$ and two-dimensional solvable ideal $R$, are described.Comment: 11 page

Fluid--Gravity Correspondence under the presence of viscosity

The present work addresses the analogy between the speed of sound of a viscous, barotropic, and irrotational fluid and the equation of motion for a non--massive field in a curved manifold. It will be shown that the presence of viscosity implies the introduction, into the equation of motion of the gravitational analogue, of a source term which entails the flow of energy from the non--massive field to the curvature of the spacetime manifold. The stress-energy tensor is also computed and it is found not to be constant, which is consistent with such energy interchange

Entropic Barriers, Frustration and Order: Basic Ingredients in Protein Folding

We solve a model that takes into account entropic barriers, frustration, and the organization of a protein-like molecule. For a chain of size $M$, there is an effective folding transition to an ordered structure. Without frustration, this state is reached in a time that scales as $M^{\lambda}$, with $\lambda\simeq 3$. This scaling is limited by the amount of frustration which leads to the dynamical selectivity of proteins: foldable proteins are limited to $\sim 300$ monomers; and they are stable in {\it one} range of temperatures, independent of size and structure. These predictions explain generic properties of {\it in vivo} proteins.Comment: 4 pages, 4 Figures appended as postscript fil

Plant-nematode co-cultures in the screening of sustainable nematicides against soil-dwelling parasitic nematodes of plants

The diseases caused by plant parasitic nematodes are still a serious constraint to modern global crop production. An increasing number of active compounds in commercial nematicidal formulations is being banned from use by common policies of pest management. Farmer communities report a low efficiency for the replacement pesticides, which reflects on crop yield and productivity. Novel sustainable biopesticides are urgently needed to cope with global food demands while respecting the most recent environmental policies. Plant-nematode co-cultures offer a stable biotechnological screening tool able to assess the active compound’s nematicidal activity and its effect on host tissues, simultaneously, in an easily accessible system that simulates natural infection. These systems are being developed and optimized at the Nematology laboratory of INIAV. Preliminary results were obtained for co-cultures of Solanum lycopersicum with the nematode Meloidogyne ethiopica and S. tuberosum with Globodera pallida. Future studies will target other plant parasitic nematodes, e.g., the root lesion nematodes (Pratylenchus penetrans) in transgenic roots of potato and the pinewood nematode (Bursaphelenchus xylophilus) on in vitro pine shoots (Pinus sp.)