1,032 research outputs found
Electroweak quark-lepton symmetry and weak topological-charge confinement in the Standard Model with Dirac neutrinos
The standard electroweak model with Dirac neutrinos is extended by way of the
principles of electroweak quark-lepton symmetry and weak topological-charge
confinement to account for quark-lepton charge relations which, if not
accidental, are indicative of charge structures. A mixing in quarks and leptons
of underlying integer local charges with integer weak topological charges
associated with an additive group Z_3, fixed by the anomaly cancellation
requirement, is discussed. It is found that the electroweak difference between
topological quarks and leptons is the nonequivalence between the topological
vacua of their weak field configurations, produced by a four-instanton which
carries the topological charge, induces the universal fractional piece of
charge distinguishing quarks from leptons, and breaks the underlying symmetry.
The constituent quarks of the standard model appear as coming from topological
quarks, via the weak four-instanton event. Dual transitions occur for leptons.
It is shown that several other fundamental problems left open in the standard
electroweak model with Dirac neutrinos are solved: the one-to-one
correspondence between quark and lepton flavors, the existence of three
generations, the conservation and ungauging of B-L, the electric charge
quantization, and the confinement of fractional electric charges.Comment: 23 pages, 1 figure, uses IJMPA.cl
Photosynthesis of three dessert banana cultivars along an altitudinal gradient
Poster presented at Tropentag 2011 - Development on the Margin. Bonn (Germany), 3-7 Oct 2011
Methodological factors involved in the study of temporal binding using the open source software Labclock Web
Temporal binding occurs when an action and an outcome that follows it after a short period of time are judged as occurring closer to each other in time than they actually are. This effect has often been studied using Libet’s clock methodology. Garaizar et al. (2016) presented Labclock Web, a free HTML5 open source software that allows researchers to conduct temporal binding and other experiments using Libet’s clock through the Internet. The purpose of the three experiments presented here was to test how certain methodological modifications in the Labclock Web task could impact the temporal binding effect. In comparison with the original study, we aimed to: (a) reduce the interval between action and outcome in the delayed condition to 100 ms, instead of 500, (b) present the two types of trials, immediate and delayed, in two separate consecutive blocks, instead of intermixed, (c) use a visual, rather than auditory, outcome following the action, and (d) reduce the number of trials. In addition to its potential theoretical implications, the results confirm that Labclock Web is a useful and reliable tool for conducting temporal binding experiments and that it is well suited to measure temporal binding effects in a broad range of situations
Determination of Benthic Soil Conditions Using Nematodes: Nematode FoodWeb Conditions of Fish Ponds in the Lincoln and Desha Counties of Arkansas
We determined the health status of similar channel catfish (Ictalurus punctatus) ponds in Lincoln and Desha counties of Arkansas, using the nematode soil food web condition as our reference point. Soil nematodes were categorized into colonizer-persister (cp) groups, based on their life course characteristics e.g sensitivity to environmental changes, body size, etc. These cp groups represent different components of the soil food web, which in turn were indicators of soil conditions. Benthic soil samples were collected at four week intervals over a 4-month period, from 6-ponds in each county. The nematodes were extracted according to standard methods and the recovered nematode taxa grouped according to their cp values. The product of each nematode taxon was determined (mean number of individuals x cp value) and the sum of all members of a cp group constituted the biomass produced by that cp group. Nematodes of the cp-3 and cp-4 groups dominated in biomass productivity in ponds for both counties. These groups of nematodes represent structured components of a food web and therefore a healthy ecosystem. Lincoln county ponds had higher cp-3 and cp-4 biomass likely due to slightly less acidic conditions while Desha county ponds had a greater biomass of plant-parasitic nematodes. It was also found that free-living nematodes tolerate more acidic conditions than plant-parasitic nematodes, though this could also be related to more root tissues. Nematode biomass calculations could be useful in determining benthic soil food web conditions, which may provide a simple way of assessing environmental conditions and changes in Arkansas catfish ponds
Compounds with Antioxidant Capacity as Potential Tools Against Several Oxidative Stress Related Disorders: Fact or Artifact?
Geoportal proposal for the inventory of cultural heritage in Nabón (Ecuador)
[EN] Humanity is losing cultural heritage faster than it can be documented, preserved and disseminated. A combination of natural and human actions is heavily affecting heritage such as climate change, vandalism, looting and natural hazards such as floods, droughts, tsunamis and earthquakes. This paper presents a cooperation proposal for strengthening efforts to protect and safeguard the world¿s cultural and natural heritage through building a geoportal for the inventory of tangible and intangible cultural heritage in Cantón Nabón, province of Azuay, Ecuador. All the gathered information, historical records, old photographs, architectural and archaeological and geomorphological surveys, in combination with state-of-the-art photogrammetric documentation surveys, will integrate the new heritage geoportal. The initial implementation will be carried out by working together with local, regional and international experts, following the suggestions of the local inhabitants.The authors acknowledge the support by the Centro de
Cooperación al Desarrollo, Universitat Politècnica de València
(Research Programme ADSIDEO-COOPERACIÓN 2019).Lerma, JL.; Heras, V.; Mora Navarro, JG.; Rodas, P.; Matute, F. (2020). Geoportal proposal for the inventory of cultural heritage in Nabón (Ecuador). ISPRS. 1415-1418. https://doi.org/10.5194/isprs-archives-XLIII-B2-2020-1415-2020S1415141
Pretratamientos de la cáscara de semilla de girasol para su utilización como sustrato de plantas
La cáscara de semilla de girasol es un residuo agro-industrial de impacto medioambiental negativo que suele estar contaminado con Sclerotinia sclerotiorum, lo que imposibilita su uso como enmienda orgánica o sustrato para plantas en macetas. El objetivo de este estudio fue evaluar si el tratamiento de ureólisis o los pretratamientos previos a la fermentación fúngica en estado sólido, i.e. solarización, pasteurización, compostado y desinfección química de la cáscara con clorito de sodio o Dazomet, podrían controlar el desarrollo de la enfermedad. Además se evaluó en co-cultivo el comportamiento de dos hongos lignocelulolíticos usados para fermentación en estado sólido frente a S. sclerotiorum. Excepto el pre-tratamiento con clorito de sodio, los demás fueron efectivos en la eliminación de la viabilidad de los esclerocios, considerándose la pasteurización el más sencillo. El G. lucidum inhibió, tanto el crecimiento del micelio de S. sclerotiorum como la germinación de los esclerocios. La ureólisis fue eficaz en varios de los tratamientos, siendo óptima la realizada en presencia de 3% de urea y 35% de humedad, y el compostado pudo eliminar la viabilidad de los esclerocios al primer mes y desintegrarlos completamente al segundo. Ambos se consideran efectivos para obtener un producto de aplicación como sustrato o enmienda
Dynamics and structure of decaying shallow dipolar vortices
The current work reports on a numerical and experimental study of the evolution of decaying dipolar vortices in a shallow fluid layer. The dynamics and the structure of such vortices are investigated as a function of both their Reynolds number Re and the aspect ratio of vertical and horizontal length scales δ. By quantifying the strength of the secondary motions (vertical motions and nonzero horizontal divergence) with respect to the swirling motions of the primary vortex cores, it was found that the three-dimensionality of a shallow (δ << 1) dipolar vortex only depends on a single parameter: δ²Re. Depending on the value of this parameter, three flow regimes are observed for shallow dipolar vortices: (1) a quasi-two-dimensional regime where the structure of the dipolar vortex remains almost unchanged throughout its lifetime, (2) a transitional regime where the structure presents some three-dimensional characteristics but remains coherent, and (3) a three-dimensional regime where the structure of the dipolar vortex acquires a complicated three-dimensional shape with a persistent spanwise vortex at its front
Inertial oscillations in a confined monopolar vortex subjected to background rotation
We study the axisymmetric inertial oscillations in a confined monopolar vortex under the influence of background rotation. By first focusing on the inviscid linear dynamics, and later studying the effects of viscosity and of a no-slip bottom, we characterize the effects of rotation and confinement. It was found that background rotation allows for oscillations outside the vortex core even with frequencies larger than 2O, with O the background rotation rate. However, confinement is necessary for the system to sustain oscillations with frequencies smaller than 2O. Through the analytical solution for a small perturbation of a Rankine vortex, we obtain five regimes where the oscillations are qualitatively different, depending on their frequency. Numerical results for the linear inviscid waves sustained by a Lamb–Oseen vortex show a similar behavior. The effects of viscosity are twofold: the oscillations are damped and the vortex sustaining the oscillations is modified. When a no-slip bottom is considered, a boundary layer drives a secondary motion superimposed on the inertial oscillations. In this case, the vortex is quickly damped, but the oscillations persist due to the background rotation
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