Linkages between Market Participation and Productivity: Results from a Multi-Country Farm Household Sample

We build upon international trade literature to analyze the direction of causality between market participation and productivity. Cross-country household data from Tanzania, Vietnam and Guatemala are used in a 2SLS approach with market participation and productivity as endogenous variables. Results indicate that households with higher productivity tend to participate in agricultural markets regardless of market access factors. In contrast, having better market access does not necessarily lead to higher productivity. This finding suggests that investments in market access infrastructure provide minimal, if any, improvements in agricultural productivity; whereas programs targeted at enhancements in farm structure and capital have the potential to increase both productivity and market participation.International Relations/Trade, Marketing, Productivity Analysis,

Agricultural Prices and Income Distribution among Farmers: A Whole-Household, Multi-Country, Multi-Year Analysis

Recent studies have emphasized that the poorest farmers are often net buyers of key commodities and therefore harmed by rising prices. We use LSMS data from Tanzania, Vietnam and Guatemala to test the degree of net purchases or sales by income level. We find that poorer farmers may be net buyers of individual crops, but only the poorest are net buyers of all crops. More generally, net sales among poor farmers are low. We conclude that agricultural price changes have a diverse but limited influence on poor farmers’ welfare, because their farm sales tend to be offset by food purchases.market participation, poverty, inequality, multi-continent multicountry, Agricultural Finance,

Self-consistent Green's functions calculation of the nucleon mean-free path

The extension of Green's functions techniques to the complex energy plane provides access to fully dressed quasi-particle properties from a microscopic perspective. Using self-consistent ladder self-energies, we find both spectra and lifetimes of such quasi-particles in nuclear matter. With a consistent choice of the group velocity, the nucleon mean-free path can be computed. Our results indicate that, for energies above 50 MeV at densities close to saturation, a nucleon has a mean-free path of 4 to 5 femtometers.Comment: 5 pages, 4 figures. Minor changes, bibliography corrected. Accepted version in Phys. Rev. Let

Invariant manifolds and equilibrium states for non-uniformly hyperbolic horseshoes

In this paper we consider horseshoes containing an orbit of homoclinic tangency accumulated by periodic points. We prove a version of the Invariant Manifolds Theorem, construct finite Markov partitions and use them to prove the existence and uniqueness of equilibrium states associated to H\"older continuous potentials.Comment: 33 pages, 6 figure

The Trichoptera of Panama XIII. Further new country records for caddisflies (Insecta: Trichoptera) from the Republic of Panama

The Republic of Panama currently includes 414 recorded species of Trichoptera. Herein we add two new genera (Hydroptilidae: Angrisanoia Ozdikmen, 2008 and Mayatrichia Mosely, 1937) and 17 new country records (Philopotamidae: Chimarra (C.) tapanti Blahnik, Wormaldia bolivari Muñoz-Quesada and Holzenthal, and Wormaldia zunigae Muñoz-Quesada and Holzenthal; Hydropsychidae: Centromacronema pygmaeum Botosaneanu; Hydroptilidae: Brysopteryx esparta Harris and Holzenthal, Byrsopteryx solisi Harris and Holzenthal, Costatrichia falsa Santos, Takiya, and Nessimian, Mayatrichia illobia Harris and Holzenthal, Metrichia amplitudinis Bueno-Soria and Holzenthal, Ochrotrichia boquillas Moulton and Harris, O. conformalis Bueno-Soria and Holzenthal, O. quinealensis Bueno-Soria and Holzenthal, and O. unica Bueno-Soria and Santiago; Leptoceridae: Triaenodes morai Holzenthal and Andersen; Odontoceridae: Marilia kingsolveri Bueno-Soria and Rojas-Ascencio; and, Helicopsychidae: Helicopsyche alajuela Johanson and Holzenthal and Helicopsyche breviterga Flint) to Panama’s caddisfly fauna. The newly recorded taxa increase Panama’s total known caddisfly fauna to 431 species, distributed among 15 families and 55 genera. These results are part of an ongoing effort to characterize the caddisfly fauna of Panama, and to evaluate the aquatic insect diversity of the country’s major watersheds (cuencas). La República de Panamá actualmente incluye 414 especies registradas de Trichoptera. Aquí agregamos dos nuevos géneros (Hydroptilidae: Angrisanoia Ozdikmen, 2008 y Mayatrichia Mosely, 1937) y 17 nuevos registros para el país (Philopotamidae: Chimarra (C.) tapanti Blahnik, Wormaldia bolivari Muñoz-Quesada y Holzenthal, y Wormaldia zunigae Muñoz-Quesada y Holzenthal; Hydropsychidae: Centromacronema pygmaeum Botosaneanu; Hydroptilidae: Brysopteryx esparta Harris y Holzenthal, Byrsopteryx solisi Harris y Holzenthal, Costatrichia falsa Santos, Takiya, y Nessimian, Mayatrichia illobia Harris y Holzenthal, Metrichia amplitudinis Bueno-Soria y Holzenthal, Ochrotrichia boquillas Moulton y Harris, Ochrotrichia conformalis Bueno-Soria y Holzenthal, Ochrotrichia quinealensis Bueno-Soria y Holzenthal, y Ochrotrichia unica Bueno-Soria y Santiago; Leptoceridae: Triaenodes morai Holzenthal y Andersen; Odontoceridae: Marilia kingsolveri Bueno-Soria y Rojas- Ascencio; y, Helicopsychidae: Helicopsyche alajuela Johanson y Holzenthal y Helicopsyche breviterga Flint) a la fauna de Trichoptera de Panamá. Los taxones recien reportados aumentan el total de la fauna de Trichoptera de Panamá a 431 especies, distribuidas en 15 familias y 55 géneros. Estos resultados son parte de un esfuerzo continuo para caracterizar la fauna de Trichoptera y para evaluar la diversidad de insectos acuáticos de las principales cuencas hidrográficas (cuencas) de Panamá

Morfologia comparada das gônadas de pentatomídeos de importância agrícola.

Os percevejos fitófagos são de grande importância agrícola e afetam a produtividade de algumas culturas. O presente trabalho teve como objetivo avaliar o sistema reprodutor desses percevejos, e fazer uma análise comparativa para constatar se pode haver distinções morfológicas intra e inter-específicas

Avaliação dos estágios de desenvolvimento gonodal de percevejos fitófagos (Heteroptera: Pentatomidae).

O objetivo deste trabalho é avaliar o estádio de desenvolvimento das gônadas de diferentes espécies de percevejos fitófagos, caracterizando seu período de diapausa.Pôster - graduação

Statistical Assessment of In-Plane Masonry Panels Using Limit Analysis with Sliding Mechanism

Historical masonry structures have a great interest in civil engineering because they constitute a large part of the world's building heritage. In this paper, the effects that different geometrical (panel ratio, block ratio, and bond type) and mechanical (friction ratio) parameters have on the in-plane structural response of brick masonry panels are investigated. A discrete modeling approach, based on a limit analysis and capable of reproducing sliding mechanisms, formulation by one of the authors has been adopted, enhanced, and implemented. Results, in terms of collapse multipliers and collapse mechanisms, are presented and analyzed following a systematic statistical approach. Statistically significant effects have been found for each factor considered. Furthermore, the statistical model adopted included nonlinear terms that allowed the identification of whether the effect of one parameter on the response depends on the level of any other parameters. Thus, it was observed that two-way factor interactions played an important role in the in-plane response of masonry panels. The panel ratio-friction ratio two-way factor interaction was the one with a more significant effect

Determinação da diapausa pelo desenvolvimento gonadal em percevejos de importância agrícola.

A diapausa é a suspensão do desenvolvimento do inseto devido a fatores bióticos e/ou abióticos, que permitem ao inseto sobreviver em uma condição adversa. O objetivo do trabalho foi avaliar as estruturas reprodutivas de percevejos de importância agrícola da família Pentatomidae e identificar fêmeas que estão no período de diapausa. As espécies avaliadas foram: Euschistus heros, Tibraca limbativentris e Oebalus ypsilongriseus, coletados na safra 2012/2013, no Estado de Goiás. As dissecações foram realizadas com o auxílio de um microscópio estereoscópio, placa de Petri com parafina para a fixação dos percevejos submersos em água destilada ou álcool 70%, que permite a visualização da estrutura reprodutiva. A diapausa foi caracterizada por fêmeas com ovários imaturos e diferenciadas das fêmeas no início da fase reprodutiva devido a presença de poucos ovócitos. Foram observados ovários em duas situações distintas: imaturas ou maduras. As gônadas imaturas apresentaram uma estrutura afilada, caracterizadas pela ausência de ovócitos, esse padrão foi observado em todos os indivíduos imaturos. As gônadas maduras foram subdivididas em dois grupos, fêmeas no início ou em plena fase reprodutiva. As fêmeas no início da atividade reprodutiva apresentaram ovócitos localizados apenas na parte inferior dos ovaríolos e as fêmeas em plena atividade reprodutiva possuíam aproximadamente 16 ovócitos distribuídos em todo ovário, caracterizando um ovário completamente preenchido. 58% dos indivíduos de T. limbativentris coletados no período de novembro/2012 (inicio de safra), 43% dos E. heros coletados em março/2013 (final de safra) e 67% dos indivíduos de O. ypsilongriseus coletados em novembro/2013 (inicio de safra) possuíam gônadas imaturas. Portanto, mais de 40% de fêmeas com gônadas imaturas, indicam que os indivíduos estavam entrando ou saindo do período de diapausa