727 research outputs found
Noise and Full Counting Statistics of Incoherent Multiple Andreev Reflection
We present a general theory for the full counting statistics of multiple
Andreev reflections in incoherent superconducting-normal-superconducting
contacts. The theory, based on a stochastic path integral approach, is applied
to a superconductor-double barrier system. It is found that all cumulants of
the current show a pronounced subharmonic gap structure at voltages
. For low voltages , the counting statistics
results from diffusion of multiple charges in energy space, giving the th
cumulant , diverging for . We show that this
low-voltage result holds for a large class of incoherent
superconducting-normal-superconducting contacts.Comment: 4 pages, 4 figure
Science education for sustainability, epistemological reflections and educational practices: from natural sciences to trans-disciplinarity.
Caracterización fisicoquímica y estabilidad oxidativa de aceites comestibles de semillas de sacha inchi microencapsulados y secados por aspersión
The aim of this work was to obtain sacha inchi oil (SIO) microcapsules from two different species, Plukenetia volubilis L. (SIVO) and Plukenetia huayllabambana L. (SIHO), using different biopolymers as wall materials and spray drying technology. The physicochemical characteristics such as encapsulation efficiency, particle size, morphology and oxidative stability were analyzed in order to select the best formulation that could potentially be used as an ingredient in the development of functional food. Bulk SIO and four formulations were tested for each oil ecotype, using different encapsulating agents: maltodextrin (MD), Arabic gum (AG), whey protein concentrate (WPC) and modified starch HI-CAP®-100 (H). Microcapsules made of H presented the highest oxidative stability and encapsulation efficiency compared to AG, AG:MD or AG:MD:WPC formulations.El objetivo de este trabajo fue obtener microcápsulas de dos especies de aceite de sacha inchi (SIO), Plukenetia volubilis L. (SIVO) y Plukenetia huayllabambana L. (SIHO), utilizando diferentes biopolímeros como materiales de pared y la tecnología de secado por aspersión. Se analizaron tanto las características fisicoquímicas como la eficiencia de encapsulación, el tamaño de partícula, la morfología y la estabilidad oxidativa para seleccionar la mejor formulación que podría utilizarse como ingrediente en el desarrollo de alimentos funcionales. Se analizaron los aceites y cuatro formulaciones para cada ecotipo, usando diferentes agentes encapsulantes: maltodextrina (MD), goma Arábiga (AG), concentrado proteico de lactosuero (WPC) y almidón modificado HI-CAP®-100 (H). Las microcápsulas hechas con H presentaron la mayor estabilidad oxidativa y eficiencia de encapsulación en comparación con las formulaciones: AG; AG:MD o AG:MD:WPC
EVALUATION OF TWO GENOTYPES OF GUINEA PIGS (Cavia porcellus) FED WITH CONCENTRATED AND EXCLUSION OF FORAGE
El estudio tuvo como objetivo evaluar los parámetros productivos y el porcentaje de grasa en la carcasa de dos genotipos de cuyes (Cavia porcellus) alimentados por nueve semanas con dos tipos de dieta. Se utilizó el diseño estadístico completamente al azar con arreglo factorial 2x2, teniendo como factores dos genotipos (Cieneguilla-UNALM y Perú-INIA) y dos tipos de dietas (dieta 1: alimento balanceado, forraje verde y agua; dieta 2: alimento balanceado más vitamina C y agua), y se evaluó el peso vivo final, ganancia de peso diaria, consumo de alimento, conversión alimenticia, peso y rendimiento de carcasa, y porcentaje de grasa y porcentaje de humedad en la carcasa. El peso vivo final, ganancia de peso, conversión alimenticia y peso de carcasa a las 12 semanas de edad en cuyes del genotipo Cieneguilla fue de 1266 g, 15.6 g/día, 3.14 y 878 g, respectivamente, en tanto que en los cuyes Perú fue de 1154 g, 13.6 g/día, 3.54 y 765 g, respectivamente (p<0.05). El factor genotipo no influyó en el consumo de alimento, rendimiento de carcasa ni el porcentaje de grasa y humedad en la carcasa. Asimismo, ni el tipo de dieta ni la interacción genotipo x tipo de alimentación fueron factores significativos en los parámetros productivos evaluados.The aim of the study was to evaluate the productive performance and percent of fat in the carcass of two guinea pig(Cavia porcellus) genotypes fed for nine weeks with two types of diets. A Randomized Complete Design with 2x2 factorial arrangements was used: two genotypes (Cieneguilla-UNALM and Peru-INIA) and two diets (diet 1: concentrate supplement, forage and water, and diet 2: concentrate supplement with vitamin C and water). The final body weight, daily weight gain, dry matter intake, feed conversion, carcass weight and yield, and fat and moisture percentage of the carcasses were evaluated. The final body weight, body weight gain, feed conversion and carcass weight at 12 weeks of age in Cieneguilla animals was 1266 g, 15.6 g/day, 3.14 and 878 g respectively whereas in Peru animals was 1154 g, 13.6 g/day, 3.54 and 765 g respectively (p<0.05). The genotype did not affect dry mater intake, carcass yield, or fat and moisture percentage. Moreover, neither the type of diet nor the interaction genotype x diet were significant factors affecting the parameters under evaluation
Analysis of Shot Noise at Finite Temperatures in Fractional Quantum Hall Edge States
We investigate shot noise at {\it finite temperatures} induced by the
quasi-particle tunneling between fractional quantum Hall (FQH) edge states. The
resulting Fano factor has the peak structure at a certain bias voltage. Such a
structure indicates that quasi-particles are weakly {\it glued} due to thermal
fluctuation. We show that the effect makes it possible to probe the difference
of statistics between FQH states where quasi-particles have the
same unit charge.Finally we propose a way to indirectly obtain statistical
angle in hierarchical FQH states.Comment: 5 pages, 3 figure
A local-global principle for linear dependence of noncommutative polynomials
A set of polynomials in noncommuting variables is called locally linearly
dependent if their evaluations at tuples of matrices are always linearly
dependent. By a theorem of Camino, Helton, Skelton and Ye, a finite locally
linearly dependent set of polynomials is linearly dependent. In this short note
an alternative proof based on the theory of polynomial identities is given. The
method of the proof yields generalizations to directional local linear
dependence and evaluations in general algebras over fields of arbitrary
characteristic. A main feature of the proof is that it makes it possible to
deduce bounds on the size of the matrices where the (directional) local linear
dependence needs to be tested in order to establish linear dependence.Comment: 8 page
Pharmacological blockade of TRPA1 inhibits mechanical firing in nociceptors
<p>Abstract</p> <p>Background</p> <p>TRPA1 has been implicated in both chemo- and mechanosensation. Recent work demonstrates that inhibiting TRPA1 function reduces mechanical hypersensitivity produced by inflammation. Furthermore, a broad range of chemical irritants require functional TRPA1 to exert their effects. In this study we use the <it>ex-vivo </it>skin-nerve preparation to directly determine the contribution of TRPA1 to mechanical- and chemical-evoked responses at the level of the primary afferent terminal.</p> <p>Results</p> <p>Acute application of HC-030031, a selective TRPA1 antagonist, inhibited all formalin responses in rat C fibers but had no effect on TRPV1 function, assessed by capsaicin responsiveness. Genetic ablation experiments corroborated the pharmacological findings as C fibers from wild type mice responded to both formalin and capsaicin, but fibers from their TRPA1-deficient littermates responded only to capsaicin. HC-030031 markedly reduced the mechanically-evoked action potential firing in rat and wild type mouse C fibers, particularly at high-intensity forces, but had no effect on the mechanical responsiveness of Aδ fiber nociceptors. Furthermore, HC-030031 had no effect on mechanically-evoked firing in C fibers from TRPA1-deficient mice, indicating that HC-030031 inhibits mechanically-evoked firing via a TRPA1-dependent mechanism.</p> <p>Conclusion</p> <p>Our data show that acute pharmacological blockade of TRPA1 at the cutaneous receptive field inhibits formalin-evoked activation and markedly reduces mechanically-evoked action potential firing in C fibers. Thus, functional TRPA1 at sensory afferent terminals in skin is required for their responsiveness to both noxious chemical and mechanical stimuli.</p
Electric-Field Tuning of Spin-Dependent Exciton-Exciton Interactions in Coupled Quantum Wells
We have shown experimentally that an electric field decreases the energy
separation between the two components of a dense spin-polarized exciton gas in
a coupled double quantum well, from a maximum splitting of meV to
zero, at a field of 35 kV/cm. This decrease, due to the field-induced
deformation of the exciton wavefunction, is explained by an existing
calculation of the change in the spin-dependent exciton-exciton interaction
with the electron-hole separation. However, a new theory that considers the
modification of screening with that separation is needed to account for the
observed dependence on excitation power of the individual energies of the two
exciton components.Comment: 5 pages, 4 eps figures, RevTeX, Physical Review Letters (in press
Effect of dental education on peruvian dental students' oral health-related attitudes and behavior
This study evaluated the effect of dental education on oral health-related attitudes and behavior of students in a five-year dental program in Peru. A survey using the Hiroshima University-Dental Behavioral Inventory (HU-DBI), which consists of twenty dichotomous responses (agree-disagree) regarding oral health behavior and attitudes, was completed by Year 1 and Year 5 dental students at the Universidad Inca Garcilaso de la Vega in Lima, Peru. A total of 153 Year 1 students and 120 Year 5 students responded to the Spanish version of the HU-DBI questionnaire. The data were analyzed using chi-square tests and logistic regression analyses. Compared to the Year 1 students, the Year 5 dental students were more likely to agree with questions such as "I think I can clean my teeth well without using toothpaste" (OR=0.24, 95% CI: 0.10-0.58); "I have used a dye to see how clean my teeth are" (OR=0.19, 95% CI: 0.10-0.36); and "I have had my dentist tell me that I brush very well" (OR=0.34, 95% CI: 0.17-0.69). Overall, the data showed that the curriculum in this dental school in Peru resulted in more positive oral health-related attitudes and behavior among Year 5 dental students compared to those of Year 1 dental students
Evidencias arqueológicas de desplomes paramentales traumáticos en las Termas Marítimas de Baelo Claudia. Reflexiones arqueosismológicas
Durante los años 2011 a 2013 se han localizado, identificado y excavado parcialmente los restos de un nuevo complejo termal en la ciudad hispanorromana de Baelo Claudia (Tarifa, Cádiz), situado en el suburbium occidental de la ciudad, junto a la línea de costa. Denominadas Termas Marítimas, construidas en la primera mitad del s. II d.C. y abandonadas en época de Diocleciano/Constantino han sido excavadas estratigráficamente con detalle, habiéndose detectado la existencia de fases anteriores (que se remontan al s. II a.C.) y una continuidad de uso del ambiente en época tardorromana y moderna, vinculada con la explotación de los recursos marinos. Especialmente singular ha sido la constatación del desplome traumático de parte de los paramentos de las habitaciones del edificio en dos momentos concretos: por un lado en la Antigüedad Tardía (500 d.C. circa), ya que una unidad muraria de una de las habitaciones (H-3), anexa a la natatio, se localizó completamente derrumbada sobre el suelo, conexionada; y por otro, el desplome del muro oeste de la natatio y el oriental de la cisterna, estructuras de más de seis metros de longitud y cuatro de altura mínima conservada, desplomadas sobre los niveles de abandono del asentamiento en época bajomedieval o moderna (ss. XIV-XV d.C.). Se trata en ambas ocasiones de colapsos estructurales no habituales en circunstancias normales en los procesos de sedimentación arqueológica, por lo que es muy probable que su desplome se pueda vincular con eventos sísmicos u otras causas naturales similare
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