3,684 research outputs found
Anomalous Transport in Holographic Chiral Superfluids via Kubo Formulae
We study anomalous conductivities in Chiral Superfluids in the framework of
two different holographic models, by means of Kubo formulae. In addition, we
point out the existence of an anomalous transport phenomenon that consists in
the presence of a charge density when the superfluid velocity is aligned with a
magnetic field. It has been pointed out recently that certain chiral
conductivities in holographic superfluids exhibit universal behavior at zero
temperature. We show that anomalous conductivities always stabilize at low
temperatures in our setup. Even though the particular value they acquire is
model-dependent, it seems to be robust and determined solely by the interplay
between the broken symmetries and the anomalies.Comment: 23 pages, 22 figures. v2: references added, minor typos corrected.
v3: footnotes added; published versio
Initial conditions for inflation and the energy scale of SUSY-breaking from the (nearly) gaussian sky
We show how general initial conditions for small field inflation can be
obtained in multi-field models. This is provided by non-linear angular friction
terms in the inflaton that provide a phase of non-slow-roll inflation before
the slow-roll inflation phase. This in turn provides a natural mechanism to
star small-field slow-roll at nearly zero velocity for arbitrary initial
conditions. We also show that there is a relation between the scale of SUSY
breaking sqrt (f) and the amount of non-gaussian fluctuations generated by the
inflaton. In particular, we show that in the local non-gaussian shape there
exists the relation sqrt (f) = 10^{13} GeV sqrt (f_NL). With current
observational limits from Planck, and adopting the minimum amount of
non-gaussian fluctuations allowed by single-field inflation, this provides a
very tight constraint for the SUSY breaking energy scale sqrt (f) = 3-7 x
10^{13} GeV at 95% confidence. Further limits, or detection, from next year's
Planck polarisation data will further tighten this constraint by a factor of
two. We highlight that the key to our approach is to identify the inflaton with
the scalar component of the goldstino superfield. This superfield is universal
and implements the dynamics of SUSY breaking as well as superconformal
breaking.Comment: Invited talk at the BW2013 meetin
Solution-processed organic devices developed by a novel cost-effective patterning technique based on electrical erosion
Application of arc erosion to the patterning of metallic contacts in organic devices is presented. A home-made systems and details of the working principles are described. Advantages and drawbacks of this novel technology are discussed
Impact of Early Infestation of Two-Spotted Spider Mites (Tetranychus urticae) on Cotton Growth and Yield
Two-spotted spider mites (Tetranychus urticae Koch, 1836) are pests of vegetables, ornamentals, and row crops around the world. Two-spotted spider mites have become an important long-season pests of cotton, causing injury to cotton from an early vegetative stage. In the past eight years, Arkansas cotton acreage treated for spider mites has more than doubled and most of the increase has been attributed to early season infestations. Yield losses of up to 30% have been observed in other studies where spider mite infestation started at third true leaf. Because of the apparent change in this pest\u27s population dynamics, particularly at early stages of crop development, the objective of the present study was to understand the impact of two spotted spider mites on cotton growth and yield. This project focuses on the impact of the timing and duration of infestations. Cotton plots were artificially infested at fourth, sixth true leaf in 2012, and at cotyledon and fourth true leaf during 2013. Both years included three infestation durations (short, medium, and long) at each infestation time. Two-spotted spider mites remaining on cotton at damaging densities for two weeks or more regardless of infestation time, caused significant yield loss. However, spider mites did not cause significant yield loss when environmental conditions did not favor spider mite development for extended periods
"De Paisano a Paisano: Mexican Migrants and the Transferrence of Political Attitudes to their Countries of Origin"
Is there a link between immigration and democratization? Can immigrants transfer democratic values to their countries of origin? If so, what are the implications for the countries in question? This dissertation looks into the theoretical construct of social remittances and tests it empirically using both quantitative and qualitative methods. Quantitatively speaking, this gets tested using survey and aggregate data. Qualitatively speaking, field work was carried out in a number of Mexican States. This work found that migrants do play a role in local politics through the transference of political attitudes. This includes, but is not limited to political participation, the incumbent party's fortunes, the governor's party's coalition's chances for reelection, the overall electoral competitiveness, and third party's share of the vote. This grassroots impact, however is tempered and constrained by the same dynamics that led individuals to migrate in the first place
Microfinanzas y vivienda para inmigrantes en los E.E.U.U.: una herramienta sustentable
Preventing neighborhood deterioration through the updating of housing stock is an opportunity for promoting sustainable development. Updating dwellings suffering from not only deterioration but also those created on an incremental basis and with small resources, creates social opportunities, decreases the consumption of land, energy, and other resources, thus promoting sustainable development. Although the United States has many years of practice and theory in issues related to neighborhood revitalization and development, sectors of population lacking access to financial opportunities still remain. Current financial and housing opportunities are proving to be unaccessable for some important groups such as immigrants. Developing countries have a record of creating original strategies to alleviate problems related to housing. Microfinance for housing has evolved as one of those ideas which have emerged in an attempt to alleviate conditions facing the poor. The main goal of this article is to present an analysis of the key characteristics of a microfinance program for housing, which has been, implemented in some of the poorest counties in Texas along the U.S.-Mexico border. The program began in 2000 and appears to be working with constant clientele. Findings on this research set the groundwork for the implementation of similar programs across the U.S.La prevención del deterioro barrial mediante la renovación de viviendas se presenta como una oportunidad para promover el desarrollo sustentable. Esta renovación de viviendas, tanto deterioradas como de aquellas construidas progresivamente y con escasos recursos, crea oportunidades sociales y disminuye el consumo de suelo, energía y otros recursos, favoreciendo de esta manera el desarrollo sustentable. Si bien los Estados Unidos cuentan con años de práctica y teoría en asuntos relacionados con la revitalización y desarrollo barrial, todavía persisten algunos sectores de la población que no cuentan con acceso a oportunidades financieras. Hoy en día, estas oportunidades crediticias y de vivienda se encuentran fuera del alcance de importantes grupos de personas, como lo son los inmigrantes. Los países en desarrollo llevan la delantera en lo que se refiere a la creación de estrategias originales para atenuar los problemas relacionados con la vivienda. La microfinanciación para la obtención de viviendas ha evolucionado como una de estas ideas que surgieron para aliviar las condiciones a las que se enfrentan las personas de menos recursos. El objetivo primordial de este artículo es ofrecer un análisis de las principales características del programa de microfinanciación para la obtención de viviendas, el cual ya ha sido aplicado en algunos de los condados más pobres de Texas, ubicado en la frontera entre los Estados Unidos y México. Este programa nació el año 2000 y ha funcionado con un constante flujo de usuarios. Los resultados de esta investigación establecen las bases para la implementación de programas similares en todos los Estados Unidos
Phase-Locked Loop Based Oscillator Phase Noise Measurement Technique
Oscillators play an important role in the performance of various radio frequency (RF) systems. The generation of stable carrier and clock frequencies is necessary at both the transmitter and receiver ends of a communication system. Phase noise is the parameter used to characterize an oscillator frequency stability. This thesis introduces a phase noise measurement technique using a phase-locked loop. A 100 MHz Colpitt’s oscillator, for the phase noise source, was designed and built. The output of the oscillator was mixed down to 10 MHz, before a phase-locked loop extracted the phase noise information. Measurements were taken at RF frequencies using an HP spectrum analyzer. Finally, a feedback phase noise model was derived, such that oscillators can be designed with phase noise being a design parameter
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