Multi-Institutional Implementation of Farmer Field Schools among Nicaraguan Bean Growers. Do Different NGOs Perform Differently?

This paper analyzes how different characteristics of non-governmental organizations (NGOs) working as extension providers affect the delivery of agricultural technologies to farmers. Using farm level data from 436 Nicaraguan bean growers, we evaluate how the institutional characteristics of the NGOs that implement farmer field schools (FFS) affect their impacts on farmer choices of pest management inputs, their adoption of integrated pest management (IPM) and resulting net revenues and pesticide exposure from bean production. After controlling for endogeneity of participation in IPM training programs and for a clustered and stratified sample design, results reveal that institutional focus, expertise in IPM and the capacity of extension providers implementing FFS significantly influence FFS impacts on input choices and adoption of IPM. FFS participation by itself has no influence on farmer' pest management decisions or their net revenues.Crop Production/Industries,

Do Pesticide Hazards to Human Health and Beneficial Insects Cause or Result from IPM Adoption? Mixed Messages from Farmer Field Schools in Nicaragua

This paper analyzes the interaction between farmer training in pest management and effects on acute pesticide poisoning and populations of beneficial insects in Nicaragua. Using farm level data from Nicaraguan bean growers, including graduates of Farmer Field Schools (FFS), other integrated pest management (IPM) outreach methods, and farmers without exposure to IPM, we found that small farmers are influenced by pesticide-related acute illness experiences when adopting IPM practices and making decisions about pesticide use. However, exposure to IPM extension programs failed to reduce the use of highly toxic pesticides and increased the number of self-reported acute illness symptoms during the most recent bean crop season. IPM training did result in growth of beneficial insect populations.ecosystem service, integrated pest management, agricultural extension, Nicaragua, Farm Management, Q16,

Analogue model for anti-de Sitter as a description of point sources in fluids

We introduce an analogue model for a nonglobally hyperbolic spacetime in terms of a two-dimensional fluid. This is done by considering the propagation of sound waves in a radial flow with constant velocity. We show that the equation of motion satisfied by sound waves is the wave equation on $AdS_2\times S^1$. Since this spacetime is not globally hyperbolic, the dynamics of the Klein-Gordon field is not well defined until boundary conditions at the spatial boundary of $AdS_2$ are prescribed. On the analogue model end, those extra boundary conditions provide an effective description of the point source at $r=0$. For waves with circular symmetry, we relate the different physical evolutions to the phase difference between ingoing and outgoing scattered waves. We also show that the fluid configuration can be stable or unstable depending on the chosen boundary condition.Comment: 6 pages, 1 figure. To appear in Phys Rev

Energy transfer dynamics and thermalization of two oscillators interacting via chaos

We consider the classical dynamics of two particles moving in harmonic potential wells and interacting with the same external environment (HE), consisting of N non-interacting chaotic systems. The parameters are set so that when either particle is separately placed in contact with the environment, a dissipative behavior is observed. When both particles are simultaneously in contact with HE an indirect coupling between them is observed only if the particles are in near resonance. We study the equilibrium properties of the system considering ensemble averages for the case N=1 and single trajectory dynamics for N large. In both cases, the particles and the environment reach an equilibrium configuration at long times, but only for large N a temperature can be assigned to the system.Comment: 8 pages, 6 figure

Boundary conditions and renormalized stress-energy tensor on a Poincar\'e patch of AdS2\textrm{AdS}_2

Quantum field theory on anti-de Sitter spacetime requires the introduction of boundary conditions at its conformal boundary, due essentially to the absence of global hyperbolicity. Here we calculate the renormalized stress-energy tensor $T_{\mu\nu}$ for a scalar field $\phi$ on the Poincar\'e patch of $\text{AdS}_2$ and study how it depends on those boundary conditions. We show that, except for the Dirichlet and Neumann cases, the boundary conditions break the maximal $\textrm{AdS}$ invariance. As a result, $\langle\phi^2\rangle$ acquires a space dependence and $\langle T_{\mu\nu}\rangle$ is no longer proportional to the metric. When the physical quantities are expanded in a parameter $\beta$ which characterizes the boundary conditions (with $\beta=0$ corresponding to Dirichlet and $\beta=\infty$ corresponding to Neumann), the singularity of the Green's function is entirely subtracted at zeroth order in $\beta$. As a result, the contribution of nontrivial boundary conditions to the stress-energy tensor is free of singular terms.Comment: 7 pages. Minor Correction. Matches published versio

Analogue gravity and radial fluid flows: The case of AdS and its deformations

An analogue model for the $\text{AdS}_2$ spacetime has been recently introduced by Mosna, Pitelli and Richartz [Phys. Rev. D 94, 104065 (2016)] by considering sound waves propagating on a fluid with an ill-defined velocity profile at its source/sink. The wave propagation is then uniquely defined only when one imposes an extra boundary condition at the source/sink (which corresponds to the spatial infinity of $\text{AdS}_2$). Here we show that, once this velocity profile is smoothed out at the source/sink, the need for extra boundary conditions disappears. This, in turn, corresponds to deformations of the $\text{AdS}_2$ spacetime near its spatial infinity. We also examine how this regularization of the velocity profile picks up a specific boundary condition for the idealized system, so that both models agree in the long wavelength limit.Comment: 6 pages, 3 figures. To appear in Phys Rev

Healthcare workers in Saudi Arabia (KSA) perceive stress differently according to gender but not in cortisol levels - an immunoassay study

Background: Working in the healthcare sector is generally regarded as stress inductive, which hampers performance, yet one demanding constant accuracy. This dichotomy has led to numerous investigations on the impact from perceived stress on hospital workers but focused primarily on employing psychological methods to determine perceived stress. This study sought to employ an arguably more objective measure of chronic stress on female healthcare professionals in Saudi Arabia, by assaying the concentration of hair cortisol (HCC) in parallel with stress questionnaires. Methods: Pharmacists, nurses and lab workers participated in providing hair samples. Cortisol levels were subsequently quantified using immunoassay methods. Investigations considered the variables of age, gender, and smoking, hair coloring or bleaching or working in shifts on both stress perception and HCC. Results: On average chronic stress was perceived comparably between the different healthcare professions and not differ significantly against the female control group. However, chronic stress differed significantly between genders within the healthcare profession. In contrast, HCC levels showed no direct relation to stress perception with respect to either gender or profession. HCC did, however, show steady decreases with respect to age, as an indirect measure of experience, that contrasted against the identical scores for stress perception. Finally, night shifts, smoking or hair colouring did not produce a significant change on HCC in the healthcare cohorts. Conclusions: Women in the healthcare profession perceive stress higher irrespective of profession compared to men. Also show a pattern of decreasing levels of cortisol with increasing age despite reporting similar stress perception against younger participants

Wealth effects in emerging market economies

We build a panel of 14 emerging economies to estimate the magnitude of housing, stock market, and money wealth effects on consumption. Using modern panel data econometric techniques and quarterly data for the period 1990:1-2008:2, we show that: (i) wealth effects are statistically significant and relatively large in magnitude; (ii) housing wealth effects tend to be smaller for Asian emerging markets while stock market wealth effects are, in general, smaller for Latin American countries; (iii) housing wealth effects have increased for Asian coutries in recent years; and (iv) consumption reacts stronger to negative than to positive shocks in housing and financial wealth. JEL Classification: E21, E44, D12Consumption, emerging markets, wealth e¤ects

Wealth Effects in Emerging Market Economies

We build a panel of 14 emerging economies to estimate the magnitude of housing, stock market, and money wealth effects on consumption. Using modern panel data econometric techniques and quarterly data for the period 1990/1-2008/2, we show that; (i) wealth effects are statistically significant and relatively large in magnitude; (ii) housing wealth effects tend to be smaller for Asian emerging markets while stock markets wealth effects are, in general, smaller for Latin American countries; (iii) housing wealth effects have increased for Asian countries in recent years; and (iv) consumption reacts stronger to negative than to positive shocks in housing and financial wealth.wealth effects, consumption, emerging markets.