Spatial-scale dependencies in the predation of seeds by rodents

Summary 1. Previous studies have shown rates of seed predation in deciduous woodland to be high (on average 60%) and extremely variable in space and time. 2. Post-dispersal seed predation by forest rodents was examined simultaneously in five areas of deciduous woodland surrounding Durham City, Co. Durham. 3. This study investigated the influence of seed density, seed burial and seed species in determining the rates of seed encounter and exploitation by rodents of both native and exotic seed. The effect of within- and between-sites differences were also examined. 4. Live-trapping studies and the use of exclosure treatments revealed that Apodemus sylvaticus and Clethrionomys glareolus were the major seed predators. Together, they were responsible for removing between 55-80% of the experimental seed supply. 5. Seed burial accounted for a high proportion of the variation and significantly reduced the frequency of rodent encounter compared to surface seeds at both seed densities. Furthermore, it increased the variation in encounter due to density, species and site effects. It had no significant influence, however, on the extent to which groups of ten seeds were exploited once encountered. 6. Variations in the frequency of seed encounter and exploitation were both strongly affected by changes in seed density, with high densities increasing the chance of seed detection and removal. Significant species effects were also detected for seed encounter and exploitation. 7. Seed predation was spatially patchy, between and within experimental sites, possibly reflecting variation in the spatial distribution of seed predators. 8. The selective nature of the seed predators, plus the relative patchiness of predation intensity in space, suggest that post-dispersal seed predation may play an important role in determining the distribution and/or abundance of deciduous woodland plants

Making chiral fermion actions (almost) gauge invariant using Laplacian gauge fixing

Straight foreward lattice descriptions of chiral fermions lead to actions that break gauge invariance. I describe a method to make such actions gauge invariant (up to global gauge transformations) with the aid of gauge fixing. To make this prescription unambiguous, Laplacian gauge fixing is used, which is free from Gribov ambiguities.Comment: 3 p., Latex, (proc. Lattice '93, Dallas), 2 figs. appended, UCSD/PTH 93-4

Intergenerational Mobility and Intrahousehold Balance of Power: A Theoretical Analysis

The study of intergenerational mobility deals with questions regarding the opportunities of children and how their long run economic outcome is related to their family background. Most importantly, from a policy point of view, it is trying to understand the sources of persistence in economic status across generations. In this paper we study how family’s decisions about investments in human and non-human capital of children are an important determinant of adult’s earnings, and thus of persistence in income differentials. We propose a theoretical model of investment in children that allows parents to have different preferences in the framework of a collective model of household behavior, and investigate how the intra-household distribution of power affects children outcomes and the transmission of economic status across generations. The results altogether suggest that failure to account for intrahousehold balance of power as source of household heterogeneity might affect the interpretation of the structural parameters of interest and the evaluation of both earnings and consumption persistence.Intergenerational Mobility, Intrahousehold Balance of Power

When a Parent Is Incarcerated: A Primer for Social Workers

Offers guidance on meeting the needs of children of incarcerated parents, including reducing trauma, engaging incarcerated parents, re-entry planning, addressing domestic violence, and issues for parents in deportation proceedings. Includes resource list

Independent Impact Evaluation for the Strengthening Protections of Internationally Recognized Labor Rights in Colombia Project

[Excerpt]This report presents the end-of-project impact evaluation for the project Strengthening Protections of Internationally Recognized Labor Rights in Colombia. The project is designed to address Colombian workers’ lack of access to safe mechanisms through which they can address workers’ rights violations. The main purpose of this evaluation was to estimate the impact of CAL services on workers’ labor-related complaints and their resolution and on CAL clients’ knowledge of their labor rights. Although the specificity of the population targeted by the program and by the evaluation means that the results of this study may not be readily applicable to other contexts, the issues raised are potentially relevant in many contexts

A preliminary assessment of the effects of migration on the production structure in Europe: A labor task approach

We assess the effect of migration on the production structure in a selection of European countries for the pre-Great Recession period 2001-2009. We propose a labor-task approach where the inflow of migrants raises the relative supply of manual-physical (or simple) tasks and therefore favors simple-task intensive sectors. We use the US O*NET database in conjunction with European labor data to calculate the index of simple-task intensity at the industry and country level. The analysis confirms that a rise in employment migration rates has a generalized positive impact, but that value added increases significantly more in sectors that use more intensively simple tasks. A traditional shift-share instrument is used to overcome possible endogeneity problems

Differentiation of argentine propolis from different species of bees and geographical origins by UV spectroscopy and chemometric analysis

Bees collect vegetal resins that they mix with their wax and mechanical impurities to elaborate propolis, whose chemical composition is complex and variable depending on botanical/geographical origin, type of bee, time of year when it was produced and function in the hive. The presence of compounds that absorb UV radiation, such as those of the phenolic type: acids, esters, flavonoids and chalcones, largely responsible for their antioxidant, antimicrobial and anti-inflammatory biological activity has been reported. The objective of the present work was to establish if it was possible to differentiate Argentine propolis using UV spectroscopy and chemometric analysis, in the following cases: a) Propolis elaborated by three different species of bees (Apis mellifera, Tetragonisca fiebrigi, Scaptotrigona jujuyensis) of the same geographical origin, and b) Propolis produced by a species of bee (Apis mellifera) of four different geographical origins. UV spectrograms were performed in the 190 to 420 nm range for all the samples followed by analysis of principal components, hierarchical clusters and linear discriminants. The results showed that Argentine propolis could be differentiated in the two cases studied, and that A.mellifera, T, fiebrigi and S. jujuyensis would not use the same plant species to produce them.Fil: Maldonado, Luis María. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucuman-Santiago del Estero. Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Marcinkevicius, Karenina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucuman-Santiago del Estero. Estación Experimental Agropecuaria Famaillá; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Borelli, Romina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucuman-Santiago del Estero. Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Gennari, Gerardo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucuman-Santiago del Estero. Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Salomón, Virginia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucuman-Santiago del Estero. Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Isla, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Vera, Nancy. Universidad Nacional de Tucuman. Facultad de Bioquímica, Química y Farmacia. Instituto de Farmacia. Cátedra de Farmacoquímica; ArgentinaFil: Borelli, Valeria Soledad. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Chaco-Formosa. Estación Experimental Agropecuaria Las Breñas; Argentin

Quantum key distribution using polarized coherent states

We discuss a continuous variables method of quantum key distribution employing strongly polarized coherent states of light. The key encoding is performed using the variables known as Stokes parameters, rather than the field quadratures. Their quantum counterpart, the Stokes operators $\hat{S}_i$ (i=1,2,3), constitute a set of non-commuting operators, being the precision of simultaneous measurements of a pair of them limited by an uncertainty-like relation. Alice transmits a conveniently modulated two-mode coherent state, and Bob randomly measures one of the Stokes parameters of the incoming beam. After performing reconciliation and privacy amplification procedures, it is possible to distill a secret common key. We also consider a non-ideal situation, in which coherent states with thermal noise, instead of pure coherent states, are used for encoding.Comment: Inclusion of a discussion about noise not controlled by Eve; inclusion of a figure. A simplified version of this paper was submitted to a Conference in Brazil (XXVII ENFMC) in 16/02/200