197 research outputs found
Non-topological condensates for the self-dual Chern-Simons-Higgs model
For the abelian self-dual Chern-Simons-Higgs model we address existence
issues of periodic vortex configurations -- the so-called condensates-- of
non-topological type as , where is the Chern-Simons parameter.
We provide a positive answer to the long-standing problem on the existence of
non-topological condensates with magnetic field concentrated at some of the
vortex points (as a sum of Dirac measures) as , a question which is of
definite physical interest.Comment: accepted on Comm. Pure Appl. Mat
Mine Waste: Consolidation Behaviour of Precious Metal Tailings
All mine processing plants generate waste. These byproducts include waste rock and a fine-grained slurry referred to as ‘tailings’ (Beier, 2015). The primary objective of treating tailings is to remove water, to enhance strength and stiffness (Sobkowicz and Morgenstern, 2009). Studying the geotechnical properties of tailings is essential to understand consolidation behaviour and facilitate land reclamation. Moreover, the geochemical characteristics of tailings should be examined to examine the potential onset of acid rock drainage (ARD). Acid rock drainage occurs when pH falls below 4, which can cause metal heavy leaching as they become present in solution. This study investigates both the geotechnical and geochemical behaviour of precious metal tailings in atmospheric conditions. The geochemical parameters of interest are pH, redox potential (Eh) and electric conductivity (Ec). The Large Strain Consolidation test (LSC) was implemented to characterize the compressibility behaviour of the sample. Accordingly, the amount of deformation that the tailings underwent was measured as they were loaded to different effective stresses. In addition, the hydraulic conductivity or the velocity of water flow was measured at the end of each consolidation step. Furthermore, the chemical parameters were evaluated using standardized probes. The tailings exhibit high compressibility during self-weight consolidation due to a combination of high initial void ratio and a high initial saturated hydraulic conductivity. In addition, hydraulic conductivity decreases nonlinearly as the samples are loaded because loading reduces the pore volume. The permeability decreased two orders of magnitude during loading, from 2.14E-05 m/s to 1.60E-7 m/s. From the geochemical point of view, there is no significant change in pH as the tailings consolidate. In this scenario, the presence of calcium carbonate has an acid-neutralizing capacity. Moreover, there is a slight increase in both redox potential and electric conductivity due to exposure to the atmosphere. The increasing trend of redox potential had a slope of 10 mV per day. While the slope of electric conductivity was 9 mS/cm per day
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El archivo del estudio del racismo en México
el racismo existe y es importante que lo expliquemos y evidenciemos. No sólo porque cruza la cotidianidad y moldea las sensibilidades y las relaciones sociales, políticas y económicas de todos los sectores de la población, sino sobre todo porque el racismo es un criterio que establece los parámetros de inclusión y exclusión, de privilegio y opresión, es la "distribución social de la muerte; como una gráfica actuarial, predice quien va a florecer y quien no" (Hartman, 2007: 129). Este número dedicado a "Identidades, racismo y xenofobia en Latinoamérica" es más que bienvenido. Estos artículos y su presencia en Desacatos fortalecen el reconocimiento del racismo como un eje central en la organización social, en la experiencia cotidiana y en el entramado institucional. Aparecen, además, en un contexto en el que las crecientes ideologías posraciales vienen a reforzar el proyecto racial del mestizaje, que ya ha hecho una buena tarea al deslegitimar la importancia del racismo: "no viene al caso, aquí todos somos mestizos". Las ideologías posraciales, como dice Da Costa (2014), son todas aquellas "formas de pensamiento, discurso y acción que evaden, deslegitiman y buscan eliminar las diferencias raciales y sus efectos como tema y enfoque del conocimiento académico, de la lucha activista, del debate público y de las políticas estatales" (2014: 2). Antes de estas estrategias posraciales -que minimizan la relevancia de nociones de raza, operan por medio de relaciones de poder racializadas y que desde su negación del racismo rearticulan la desigualdad racial_____, la ideología del mestizaje había cimentado con estrategias similares un terreno de resistencia a la movilización política, social y académica alrededor del tema racial en México y en contextos semejantes en Latinoamérica. Este mestizaje ideológico, además, está basado a su vez en la enraizada experiencia colonial, en políticas civilizatorias y de modernización y en un racismo científico cruel que está ahí, suspendido, siempre listo para aparecer en escena
Bubbling solutions for Moser-Trudinger type equations on compact Riemann surfaces
We study an elliptic equation related to the Moser-Trudinger inequality on a
compact Riemann surface , where is a small parameter, is the area of ,
is the Laplace-Beltrami operator and is the area element. Given any
integer , under general conditions on we find a bubbling solution
which blows up at exactly points in , as .
When is a flat two-torus in rectangular form, we find that either seven or
nine families of such solutions do exist for . In particular, in any
square flat two-torus actually nine families of bubbling solutions with two
bubbling points do exist. If is a Riemann surface with non-constant Robin's
function then at least two bubbling solutions with exists.Comment: 41 page
"You can't read your way out of racism": Creating anti-racist action out of education in an academic library
Purpose
Under the transformational leadership of the University Librarian, University of North Carolina at Chapel Hill Libraries shifted from having an education- and programming-based “diversity committee” to a council of librarians advocating for action, anti-racism, and social justice, both within our organization and across campus. As our "you can't read your way out of racism."
Approach
With support from library leadership, the Inclusion, Diversity, Equity, and Accessibility (IDEA) Council has advanced anti-racism work in the libraries by serving as facilitators for a book discussion series, organizing a 21-day racial equity challenge, supporting staff in integrating anti-racism practices into their daily work through brown bag conversations, and facilitating the development of inclusion-focused performance management goals.
Findings
What does an anti-racist library look like, and how does our organization envision this future? These questions anchor the IDEA Council’s strategies. The libraries have witnessed a positive shift in staff participation: two-thirds of library staff participated in a Racial Equity Institute Groundwater presentation and in a library-wide book discussion series; approximately half the staff committed to our 21-day racial equity challenge. Participants were asked to reflect in conversation and through surveys.
Originality/value
The first wave of a newly established grant program funded eight staff-led projects to advance social justice in the libraries. Additional steps included caucusing by racial identity, staff-wide discussions about racial equity, and a second wave of funding for the grant program. We approach this work with cultural humility: seeking to learn from one another, our peers, and fellow activists
Physical Activity Reduces Hippocampal Atrophy in Elders at Genetic Risk for Alzheimer\u27s Disease
We examined the impact of physical activity (PA) on longitudinal change in hippocampal volume in cognitively intact older adults at varying genetic risk for the sporadic form of Alzheimer\u27s disease (AD). Hippocampal volume was measured from structural magnetic resonance imaging (MRI) scans administered at baseline and at an 18-month follow-up in 97 healthy, cognitively intact older adults. Participants were classified as High or Low PA based on a self-report questionnaire of frequency and intensity of exercise. Risk status was defined by the presence or absence of the apolipoprotein E-epsilon 4 (APOE-ε4) allele. Four subgroups were studied: Low Risk/High PA (n = 24), Low Risk/Low PA (n = 34), High Risk/High PA (n = 22), and High Risk/Low PA (n = 17). Over the 18 month follow-up interval, hippocampal volume decreased by 3% in the High Risk/Low PA group, but remained stable in the three remaining groups. No main effects or interactions between genetic risk and PA were observed in control brain regions, including the caudate, amygdala, thalamus, pre-central gyrus, caudal middle frontal gyrus, cortical white matter (WM), and total gray matter (GM). These findings suggest that PA may help to preserve hippocampal volume in individuals at increased genetic risk for AD. The protective effects of PA on hippocampal atrophy were not observed in individuals at low risk for AD. These data suggest that individuals at genetic risk for AD should be targeted for increased levels of PA as a means of reducing atrophy in a brain region critical for the formation of episodic memories
Ansiedad en tiempos de pandemia y su relación con la agresividad en el personal policial de la U.S.E. Puno, 2021
El actual estudio tuvo por finalidad determinar la correlación entre ansiedad
en tiempos de pandemia con la agresividad en el personal policial de la U.S.E. Puno.
Por consiguiente, el estudio es correlacional y de diseño no experimental; para lo
cual, se contó con la participación de 132 efectivos policiales de ambos sexos, sin
embargo, el sexo predominante fue el de los hombres; cabe mencionar que se
empleó dos instrumentos con sus respectivas propiedades psicométricas (validez
y confiabilidad) para recabar la información pertinente; los cuales son: La Escala de
Ansiedad de Zung y el Cuestionario de Agresión de Buss y Perry (versión española).
En efecto se encontró que, existe relación positiva y altamente significativa entre
las variables de estudio, esto se ve reflejado con un rs = 0.48, esto quiere decir que,
a mayor ansiedad mayor es la agresividad en el personal policial de la U.S.E. Puno,
2021
Structural, optical and vibrational properties of ZnO:M (M=Al3+ and Sr2+) nano and micropowders grown by hydrothermal synthesis
Powders of ZnO and ZnO:M (M = Al3+ and Sr2+) with 1 and 4% of M nominal content were synthetized by a hydrothermal method in a diethanolamine (DEA) medium. The samples were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), micro-Raman and photoluminescence (PL). The powder particles were spherical with average radius decreasing from 1 μm down to 70 nm with increasing Al3+ nominal content but nearly independent on the Sr2+ nominal content. The XRD and micro-Raman results indicate that both Al3+ and Sr2+ mostly incorporated substitutionally into the ZnO lattice, giving rise to compressive and tensile strain, respectively, as a result of ionic radii differences. The PL spectra for ZnO:Al exhibit a dopant-induced contribution at ∼3.1 eV, which is not observed for ZnO:Sr, due to radiative transitions involving trapping of photocarriers at theoretically expected substitutional Al3+ donor states or at Zn interstitial defects.Fil: Marín Ramírez, Oscar Alonso. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Laboratorio de Física del Sólido; ArgentinaFil: Soliz, Tania. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología; ArgentinaFil: Gutierrez, Jorge Andrés. Universidad del Quindío. Facultad de Ciencias Básicas y Tecnológicas; ColombiaFil: Tirado, Monica Cecilia. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Departamento de Nanomateriales y Propiedades Dieléctricas; ArgentinaFil: Figueroa, Carlos. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Laboratorio de Física del Sólido; ArgentinaFil: Comedi, David Mario. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Laboratorio de Física del Sólido; Argentin
Criterios de implementación ISO 14000:2015 Caso de estudio Relleno Sanitario.
El tratamiento de los residuos sólidos por el método de relleno sanitario por la organización prestadora de servicios públicos es considerado como una técnica de disposición de los mismos, que en algunas ocasiones ayuda a minimizar los perjuicios al medio ambiente y los peligros para la salud y la seguridad pública. Sin embargo, en algunos rellenos sanitarios el desarrollo de algunas actividades o procesos de una manera inadecuada hace que impacten negativamente al medio ambiente.
En el presente estudio de caso se describe el manejo de los Residuos sólidos que se lleva a cabo en el relleno sanitario BIORGANICOS Del SUR S.A E.S.P, debido a la actividad propia de este lugar es necesario que se realicen actividades que vayan en concordancia para el buen manejo y control de los impactos ambientales, para ello se realizó la
identificación de aspectos ambientales, actividades que se llevan a cabo al interior del relleno y el reconocimiento de la normatividad ambiental vigente aplicable a los procesos de la empresa.
Para el manejo de los residuos sólidos se tienen en cuenta actividades como: recibo y descargue, separación manual, desfibración del material orgánico, compostaje, manejo de lixiviados, selección y reciclaje, disposición en el relleno sanitario. Alguna de estas actividades impacta negativamente al medio ambiente y los recursos naturales, afectando al recurso agua, suelo, aire. El documento tiene como finalidad identificar dentro del proceso de manejo de residuos sólidos, la gestión ambiental y la implementación
de estrategias que permitan minimizar los impactos ambientales, basado en la norma ISO 14001 2015.The treatment of solid waste by the method of sanitary landfill by the organization providing public services is considered a disposal technique, which sometimes helps to minimize environmental damage and health and environmental hazards. public security. However, in some sanitary landfills the development of some activities or processes in an inadequate way causes them to negatively impact the environment.
This case study describes the management of solid waste that is carried out in the BIORGANICOS Del SUR SA ESP sanitary landfill, due to the activity of this place it is necessary that activities are carried out in accordance with the good management and control of environmental impacts, for this the Identification of environmental aspects, activities that are carried out inside the landfill and the recognition of the current environmental regulations applicable to the company's processes.
For the management of solid waste, activities such as: receipt and discharge, manual separation, defibration of organic material, composting, leachate management, selection and recycling, disposal in the landfill are taken into account. Some of these activities negatively impacts the environment and natural resources, affecting the water, soil, air resource. The document aims to identify within the solid waste management process, environmental management and implementation
of strategies that minimize environmental impacts, based on the ISO 14001 2015 standard
Transporte de materia organica particulada en una corriente altoandina: quebrada arrayanales (cauca – colombia)
Se determinó la dinámica temporal de la materia orgánica particulada en la quebradaArrayanales (Cauca), teniendo en cuenta los eventos de precipitación y suefecto sobre la cantidad de materia orgánica particulada fina (MOPF), gruesa(MOPG) y total (MOPT) que ingresa y es transportada aguas abajo de la Quebrada.Se planteó como objetivo establecer la cantidad y la variación de las entradas laterales,verticales y el transporte de materia orgánica particulada alóctona (MOP),contando a la precipitación y el caudal como variables hidroclimáticas para ello sedeterminó el peso seco libre en cenizas (PSLC) de MOP vertical, lateral capturaday transportada. Los resultados demuestran que la Quebrada Arrayanales, es unecosistema con tendencia al transporte de grandes cantidades de MOPG, conbajo potencial de almacenamiento y mecanismos para el ingreso de materia orgánicaalóctono, que dependen del régimen de precipitaciones. Las precipitacionesse relacionaron mayormente con el transporte de MOPG, que con la MOPF. Losaportes verticales y laterales fueron dominados por MOPG, con promedios totalesde 10,86 g PSLC m-2 y 6,05 g PSLC m-2 respectivamente. El transporte en el tramode estudio fue de 37,83 g m-3 MOPT, 32,88 g m-3 MOPG y 4,94 g m-3 MOPF
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