664 research outputs found

    Bilepton effects on the WWV^* vertex in the 331 model with right-handed neutrinos via a SU_L(2)XU_Y(1) covariant quantization scheme

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    In a recent paper, we investigated the effects of the massive charged gauge bosons (bileptons) predicted by the minimal 331 model on the off-shell vertex WWV^* (V=gamma, Z) using a SU_L(2) X U_Y(1) covariant gauge-fixing term for the bileptons. We proceed along the same lines and calculate the effects of the gauge bosons predicted by the 331 model with right-handed neutrinos. It is found that the bilepton effects on the WWV^* vertex are of the same order of magnitude than those arising from the SM and several of its extensions, provided that the bilepton mass is of the order of a few hundred of GeVs. For heavier bileptons, their effects on the WWV^* vertex are negligible. The behavior of the form factors at high energies is also discussed as it is a reflect of the gauge invariance and gauge independence of the WWV^* Green function obtained via our quantization method.Comment: Replaced to match published versio

    A Hybrid Least Squares and Principal Component Analysis Algorithm for Raman Spectroscopy

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    Raman spectroscopy is a powerful technique for detecting and quantifying analytes in chemical mixtures. A critical part of Raman spectroscopy is the use of a computer algorithm to analyze the measured Raman spectra. The most commonly used algorithm is the classical least squares method, which is popular due to its speed and ease of implementation. However, it is sensitive to inaccuracies or variations in the reference spectra of the analytes (compounds of interest) and the background. Many algorithms, primarily multivariate calibration methods, have been proposed that increase robustness to such variations. In this study, we propose a novel method that improves robustness even further by explicitly modeling variations in both the background and analyte signals. More specifically, it extends the classical least squares model by allowing the declared reference spectra to vary in accordance with the principal components obtained from training sets of spectra measured in prior characterization experiments. The amount of variation allowed is constrained by the eigenvalues of this principal component analysis. We compare the novel algorithm to the least squares method with a low-order polynomial residual model, as well as a state-of-the-art hybrid linear analysis method. The latter is a multivariate calibration method designed specifically to improve robustness to background variability in cases where training spectra of the background, as well as the mean spectrum of the analyte, are available. We demonstrate the novel algorithm’s superior performance by comparing quantitative error metrics generated by each method. The experiments consider both simulated data and experimental data acquired from in vitro solutions of Raman-enhanced gold-silica nanoparticles

    Higgs mediated Double Flavor Violating top decays in Effective Theories

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    The possibility of detecting double flavor violating top quark transitions at future colliders is explored in a model-independent manner using the effective Lagrangian approach through the tuiτμt \to u_i\tau \mu (ui=u,cu_i=u,c) decays. A Yukawa sector that contemplates SUL(2)×UY(1)SU_L(2)\times U_Y(1) invariants of up to dimension six is proposed and used to derive the most general flavor violating and CP violating qiqjHq_iq_jH and liljHl_il_jH vertices of renormalizable type. Low-energy data, on high precision measurements, and experimental limits are used to constraint the tuiHtu_iH and HτμH\tau \mu vertices and then used to predict the branching ratios for the tuiτμt \to u_i\tau \mu decays. It is found that this branching ratios may be of the order of 104105 10^{-4}-10^{-5}, for a relative light Higgs boson with mass lower than 2mW2m_W, which could be more important than those typical values found in theories beyond the standard model for the rare top quark decays tuiViVjt\to u_iV_iV_j (Vi=W,Z,γ,gV_i=W,Z,\gamma, g) or tuil+lt\to u_il^+l^-. %% LHC experiments, by using a total integrated luminosity of 3000fb1\rm 3000 fb^{-1} of data, will be able to rule out, at 95% C.L., DFV top quark decays up to a Higgs mass of 155 GeV/c2c^2 or discover such a process up to a Higgs mass of 147 GeV/c2c^2.Comment: 24 pages, 11 figure

    One-loop effects of extra dimensions on the WW\gamma and WWZ vertices

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    The one-loop contribution of the excited Kaluza-Klein (KK) modes of the SUL(2)SU_L(2) gauge group on the off-shell WWγWW\gamma and WWZWWZ vertices is calculated in the context of a pure Yang-Mills theory in five dimensions and its phenomenological implications discussed. The use of a gauge-fixing procedure for the excited KK modes that is covariant under the standard gauge transformations of the SUL(2)SU_L(2) group is stressed. A gauge-fixing term and the Faddeev-Popov ghost sector for the KK gauge modes that are separately invariant under the standard gauge transformations of SUL(2)SU_L(2) are presented. It is shown that the one-loop contributions of the KK modes to the off-shell WWγWW\gamma and WWZWWZ vertices are free of ultraviolet divergences and well-behaved at high energies. It is found that for a size of the fifth dimension of R11TeVR^{-1}\sim 1TeV, the one-loop contribution of the KK modes to these vertices is about one order of magnitude lower than the corresponding standard model radiative correction. This contribution is similar to the one estimated for new gauge bosons contributions in other contexts. Tree-level effects on these vertices induced by operators of higher canonical dimension are also investigated. It is found that these effects are lower than those generated at the one-loop order by the KK gauge modes.Comment: 19 pages, 9 figures. Some typos were correcte

    Drilling on the Moon and Mars: Developing the Science Approach for Subsurface Exploration with Human Crews

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    DOMEX (Drilling on the Moon and Mars in Human Exploration) is using analog missions to develop the approach for using human crews to perform science activities on the Moon and Mars involving exploration and sampling of the subsurface. Subsurface science is an important activity that may be uniquely enabled by human crews. DOMEX provides an opportunity to plan and execute planetary mission science activities without the expense and overhead of a planetary mission. Objectives: The objective of this first in a series of DOMEX missions were to 1) explore the regional area to understand the geologic context and determine stratigraphy and geologic history of various geologic units in the area. 2) Explore for and characterize sites for deploying a deep (10 m depth) drilling system in a subsequent field season. 3) Perform GPR on candidate drill sites. 4) Select sites that represent different geological units deposited in different epochs and collect soil cores using sterile procedures for mineralogical, organic and biological analysis. 5) Operate the MUM in 3 different sites representing different geological units and soil characteristics. 6) Collect rock and soil samples of sites visited and analyze them at the habitat. Results: At mission start the crew performed a regional survey to identify major geologic units that were correlated to recognized stratigraphy and regional geologic maps. Several candidate drill sites were identified. During the rest of the mission, successful GPR surveys were conducted in four locations. Soil cores were collected in 5 locations representing soils from 4 different geologic units, to depths up to 1m. Soil cores from two locations were analyzed with PCR in the laboratory. The remainder were reserved for subsequent analysis. XRD analysis was performed in the habitat and in the field on 39 samples, to assist with sample characterization, conservation, and archiving. MUM was deployed at 3 field locations and 1 test location (outside the habitat) where it operated autonomously for 2-4 hours at each site. Depths achieved ranged from 15 to 70 cm depending on the soil compressive strength and the presence and depth of subsurface indurated layers. Subsurface samples weighing 0.5 to 1 g were collected at the deepest depth encountered at each of the sites using the MUM automated sample collection system, and subsequently analyzed with XRD. Downhole inspection of holes produced by MUM with the Raman spectrometer was acquired on two of the holes and spectral features associated with selenite were identified in specific soil layers. Previously unreported fossilized remains of vertebrate fauna from the Jurassic era were discovered during our mission. Analysis of mineral biomarkers associated with this discovery are underway

    Factorial design for preparing chitosan nanoparticles and its use for loading and controlled release of indole-3-acetic acid with effect on hydroponic lettuce crops

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    The excessive use of agrochemicals generates damage to the environment, so their controlled release from biodegradable nanoparticles represents a good solution. In this study, chitosan nanoparticles (CNPs) were prepared by ionic gelation with sodium tripolyphosphate (TPP), according to a 24 factorial design to evaluate the effect of different factors (chitosan amount, TPP amount, agitation speed, and agitation time) influencing the nanoparticle size (NPS) and the polydispersity index (PDI). Once established the proper conditions by the factorial design, CNPs were prepared and loaded with indole-3-acetic acid (CNP-IAA). The nanoparticles loaded with chitosan:IAA mass ratio equal to 1:0.25, showed the higher loading capacity, thus were then used for the release tests and hydroponic lettuces crops. The analysis by dynamic light scattering (DLS) reveals a mean diameter for CNPs and CNP-IAA of ~149 and ~183 nm, respectively. Moreover, further characterization by thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscopy, indicates that nanoparticles were effectively loaded with IAA. In addition, the release assays results were adjusted to the Korsmeyers-Peppas mathematical model, showing that 100% of the hormone is released in about 48 h. Also, the model fitting suggests that the release process is carried out in two steps: the first of releasing by diffusion followed by a second of sustained-release. Accordingly, our results prove that CNPs-IAA applied to the hydroponic crop of the Crocantela variety crisp lettuce (Latuca sativa L.), have a beneficial effect on the plant growth producing an increase of 30.9% in the number of lettuce leaves

    Economically Optimum Irrigation Patternsfor Grain Sorghum Production: Texas High Plains

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    Agricultural production and associated economic effects of irrigation on the Texas High Plains are seriously threatened by a rapidly declining groundwater supply and a swift upward trend in energy costs. To optimize the amount of irrigation water to be applied during specified periods of the production process, a stochastic open-loop feedback control policy was built into a grain sorghum growth simulation model. The control policy operated under the basis of constant revision of the expectations generated at every starting point for each of the production periods. If discrepancies between the expected and the realized values existed, then, based on current conditions a reevaluation of the control variable, irrigation water, was made and the decision for the first period adopted. This process continued throughout each period of the growing season. Within the stochastic policy designed, the values for the control variable were obtained by numerical search. The model was applied to estimate optimal irrigation strategies and the impact of fuel curtailments on them. Initially, optimal irrigation strategies were developed under the assumption of perfect knowledge. Under this assumption, the results indicated there was not a unique strategy to be applied at all times. The quantities of irrigation water to apply at each period depended on the initial or starting conditions. Since one of the purposes of building the model was to make it perform under stochastic or real world conditions, the assumption of complete knowledge was relaxed to consider the case where the climatic environment was unknown. As in the deterministic case, the optimal amounts of irrigation water, by period. It was also observed, that with the open-loop feedback control, the results obtained for yields did not differ substantially from those obtained in the perfect knowledge case. The discrepancies among the two cases were primarily in the optimal amount of water applied and therefore in net returns. In the stochastic case, the use of irrigation water had a mean value approximately 25 percent more than in the case of perfect knowledge. The effect of a fuel or irrigation curtailment was estimated for alternative time spans. When curtailments had a length of 10 days, there were no perceptible changes in the amount of net returns or yields, as compared to the no-curtailment case. The implication drawn was that by having frequent irrigation periods and applying optimal amounts of water, the adverse effects of 10-day curtailment periods were buffered. The cases of twenty and thirty-day periods were found to have highly negative effects on the outcomes, especially net revenues, which decreased about 50 percent (from 99to99 to 50) in the curtailment case of 40 - 70 days after plant emergence compared to the no-curtailment value. The effects were not only on a decreased amount of returns perceived but also on an increased spectrum of relative fluctuation (from 18 percent to 68 percent for the same situations mentioned above). It was also found that for the same time-span type of curtailments the effects were conditioned to the period in which they Occurred. However, the 20 or 30 day curtailment period might be applicable to much shorter actual fuel curtailment periods. Producers lose not only the time of fuel curtailments, but also, they must cover many acres with a limited number of wells. As a result, a 10-day fuel curtailment could easily result in a 20 to 30 day delayed irrigation. To summarize, improved irrigation distribution technology could result in increased yields and less irrigation water by simply having very close control on timing and quantity of water applied

    Social isolation and its relationship to multidimensional poverty

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    While the multidimensionality of poverty is well-recognised, one dimension of poverty which has been often overlooked is weak social connectedness. This paper draws on conceptual, participatory and measurement literatures to show that social connectedness appears to be an important missing ingredient of multidimensional poverty analyses, with social isolation being a feature which exacerbates the condition of poor persons. To provide contextual detail as to its impact on persons in marginalized communities, we present qualitative primary data from South Africa and Mozambique and review pertinent studies of the First Nations of Canada and among persons with disability. A policy challenge for social isolation is that it is often seen as stemming from an individuals’ capacity rather than resulting from the broader social context. The closing section outlines areas for policy. The study of multidimensional poverty has enlarged the range of factors which are considered part of impoverishment. For example, the Commission on Global Poverty Measurement led by Tony Atkinson proposed that physical security from violence be regularly monitored by the World Bank as a non-monetary dimension of poverty (World Bank, 2016). We argue in this paper that social isolation and decreased social connectedness can be important results of living in poverty, are themselves an aspect of poverty, and are also contributory factors to the persistence of poverty; consequently, they merit more extensive analysis than they often receive. This paper aims to catalyse that analysis by drawing together literature, case studies illuminating social isolation in different contexts, and observations of policy responses, in order to suggest how appropriate analyses of social isolation can meet a deeply human demand and improve policy design. Synthesising a dispersed literature, we first examine how social isolation fits into multidimensional poverty conceptually. We then discuss primary field research from South Africa and Mozambique which reveals the influence of social isolation in the lived experience of poverty from the perspective of the impoverished themselves. The next section draws on documented histories of the Aboriginal peoples of Canada to investigate how isolation – in residential schools – created long-term impacts on poverty and isolation. Finally, drawing on the discussion on incorporating people with disabilities, we explore how reducing social isolation, through programmes aimed at reintegrating people with disabilities into their communities, can provide insight into directions for policy. In concluding, we show how addressing the issue of social isolation in a concerted fashion while recognizing that it arises in diverse contexts can potentially mitigate poverty

    Reversible cardiomyopathy in a patient with Marfan’s syndrome. Case report

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    Marfan´s syndrome is a multisystemic, autosomal dominant congenital abnormality of variable penetrance that affects the integrity of connective tissue. In the cardiovascular system, the dysfunction of the physiology of the aortic root and the myocardial fibrosis originates non-ischemic cardiomyopathy independent of valve lesions. Few data have been reported on the prevalence of arrhythmias and its impact on heart function. We present a 21-year-old man with Marfan’s syndrome and heart failure with frequent supraventricular arrhythmias and aortic root dilation. After ablation in the posteroseptal area of the mitral ring and Tirone David Surgery, there was clinical improvement, the left ventricular ejection fraction increased dramatically from 33% to 46%, the left ventricular end-diastolic volume decreased from 90 ml/m2 to 77 ml/m2 and the NT-proBNP decrease from 1100 pg/mL at 180 pg/mL.Marfan´s syndrome is a multisystemic, autosomal dominant congenital abnormality of variable penetrance that affects the integrity of connective tissue. In the cardiovascular system, the dysfunction of the physiology of the aortic root and the myocardial fibrosis originates non-ischemic cardiomyopathy independent of valve lesions. Few data have been reported on the prevalence of arrhythmias and its impact on heart function. We present a 21-year-old man with Marfan’s syndrome and heart failure with frequent supraventricular arrhythmias and aortic root dilation. After ablation in the posteroseptal area of the mitral ring and Tirone David Surgery, there was clinical improvement, the left ventricular ejection fraction increased dramatically from 33% to 46%, the left ventricular end-diastolic volume decreased from 90 ml/m2 to 77 ml/m2 and the NT-proBNP decrease from 1100 pg/mL at 180 pg/mL

    Vertical structure use by the Stout Iguana (Cyclura pinguis) on Guana Island, BVI

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    The Stout Iguana (Cyclura pinguis) is a critically endangered species endemic to the Puerto Rico Bank and currently restricted to the British Virgin Islands (BVI). Our study on Guana Island, BVI, focused on vertical structure use by adult (n = 4) and juvenile (n = 11) iguanas with tracking bobbins. We recorded structure types used, heights attained on structures, distances between structures, and structure sizes. We found that Stout Iguanas used vertical structure more than previously documented. Trees comprised a significantly greater (P <  0.001) proportion of structures used by juveniles than by adults, whereas rocks comprised the greatest proportion of structures used by adults. In addition to differential structure use, juveniles climbed significantly higher (2.4 vs. 0.9 m on average; P < 0.001) than adults. We found no difference in the diameter or distance between structures used by adults and juveniles. Our results suggest that vertical structure use may be an important habitat element for free-ranging juvenile Stout Iguanas. Habitat management that provides vertical structure may be advantageous for the conservation of this species
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