Productivity of Nations: a Stochastic Frontier Approach to Tfp Decomposition

This Paper Tackles the Problem of Aggregate Tfp Measurement Using Stochastic Frontier Analysis (Sfa). Data From Penn World Table 6.1 are Used to Estimate a World Production Frontier For a Sample of 75 Countries Over a Long Period (1950-2000) Taking Advantage of the Model Offered By Battese and Coelli (1992). We Also Apply the Decomposition of Tfp Suggested By Bauer (1990) and Kumbhakar (2000) to a Smaller Sample of 36 Countries Over the Period 1970-2000 in Order to Evaluate the Effects of Changes in Efficiency (Technical and Allocative), Scale Effects and Technical Change. This Allows Us to Analyze the Role of Productivity and Its Components in Economic Growth of Developed and Developing Nations in Addition to the Importance of Factor Accumulation. Although not Much Explored in the Study of Economic Growth, Frontier Techniques Seem to Be of Particular Interest For That Purpose Since the Separation of Efficiency Effects and Technical Change Has a Direct Interpretation in Terms of the Catch-Up Debate. The Estimated Technical Efficiency Scores Reveal the Efficiency of Nations in the Production of Non Tradable Goods Since the Gdp Series Used is Ppp-Adjusted. We Also Provide a Second Set of Efficiency Scores Corrected in Order to Reveal Efficiency in the Production of Tradable Goods and Rank Them. When Compared to the Rankings of Productivity Indexes Offered By Non-Frontier Studies of Hall and Jones (1996) and Islam (1995) Our Ranking Shows a Somewhat More Intuitive Order of Countries. Rankings of the Technical Change and Scale Effects Components of Tfp Change are Also Very Intuitive. We Also Show That Productivity is Responsible For Virtually All the Differences of Performance Between Developed and Developing Countries in Terms of Rates of Growth of Income Per Worker. More Important, We Find That Changes in Allocative Efficiency Play a Crucial Role in Explaining Differences in the Productivity of Developed and Developing Nations, Even Larger Than the One Played By the Technology Gap

Agricultura en el Cono Sur ¿Qué se conoce, qué falta por conocer?

The growing global demand for food has promoted grain production in four countries from the South Cone (Argentina, Bolivia, Paraguay, and Uruguay). The increment in productivity of the last 20 years has been based mainly in aggressive land incorporation to agriculture, especially with soybeans, and a drastic reduction of the areas under pastures, and, in a minor scale, for yield increments. Yield increments of wheat and corn in the region are interesting; however, they will not be enough to satisfy the demand by 2050 which requires duplication in yields. The South Cone land expansion and grain yield increments have had positive and negative impacts. Among the positive impacts are the increased productivity and the consequent social and economic benefit, industry development, and greater food security. On the other hand, expansion and yield increment have also had economic and social negative impacts such as water and wind erosion, soil salinization, decrements in soil organic matter content, desertification, soil compaction, soil fertility reduction, diffuse soil, water and air pollution, presence of resistant weeds, biodiversity losses, reduction in inputs and resources use efficiency, and land concentration and reduction in job opportunities. Several of these negative impacts have contributed to the yield stagnation in many agro systems of the region. This article discusses aspects related to soil and crop management in the production systems of the region regarding: 1) its actual complexity (what is known), and 2) concepts and lines of work which can contribute to a sustainable agriculture (¿what needs be known?).Las crecientes demandas de alimentos a nivel global han impulsado la producción de granos en los países del Cono Sur (Argentina, Bolivia, Paraguay y Uruguay). El aumento de la producción de granos de los últimos 20 años se ha basado principalmente en una fuerte expansión del área sembrada, en especial la de soya, a partir de la incorporación de nuevas áreas y del cambio de uso de la tierra con una drástica reducción de las áreas bajo pasturas y, en menor medida, por el incremento en los rendimientos. Si bien la región muestra interesantes incrementos de rendimientos de trigo y maíz con respecto a los estimados mundiales, los mismos no serían suficientes para satisfacer la demanda para el año 2050 que requiere que éstos se dupliquen. La expansión y crecimiento de la producción de granos en el Cono Sur presentan aspectos positivos y negativos. Entre los aspectos positivos se pueden incluir los aumentos en producción con el consecuente beneficio económico y social, el desarrollo de la industria y la mayor seguridad alimentaria. Sin embargo, la expansión del área de cultivo y el crecimiento de la producción ha generado costos y externalidades negativas en aspectos ambientales, económicos y sociales entre los que se pueden incluir erosión hídrica y eólica, salinización de suelos, desertificación, reducción de los contenidos de la materia orgánica, pérdida de fertilidad de los suelos, pérdida de estructura y compactación de suelos, contaminación difusa de aguas, suelos y aire, presencia de malezas resistentes, pérdidas de biodiversidad, reducción de efectividad y eficiencia de recursos e insumos, concentración de tierras y perdidas de fuentes de empleo. Muchos de estos costos y externalidades han contribuido a que los rendimientos de los cultivos se hayan estancado en muchos agroecosistemas de la región. En este artículo se discuten aspectos relacionados al manejo de suelos y cultivos y de los sistemas de producción en cuatro países del Cono Sur en lo que se refiere a: 1) su compleja actualidad (que se conoce), y 2) conceptos y líneas de trabajo que podrían contribuir a una agricultura sostenible (¿qué se debe conocer?)

Entropy in Spin Foam Models: The Statistical Calculation

Recently an idea for computing the entropy of black holes in the spin foam formalism has been introduced. Particularly complete calculations for the three dimensional euclidean BTZ black hole were done. The whole calculation is based on observables living at the horizon of the black hole universe. Departing from this idea of observables living at the horizon, we now go further and compute the entropy of BTZ black hole in the spirit of statistical mechanics. We compare both calculations and show that they are very interrelated and equally valid. This latter behaviour is certainly due to the importance of the observables.Comment: 11 pages, 1 figur

WORKSHOP NACIONAL “INVESTIGAÇÃO EM OLIVICULTURA E AZEITE - RESULTADOS E APLICAÇÕES

Workshop Nacional “Investigação em Olivicultura e Azeite – Resultados e Aplicações” De 27-06-2013, 09:00 a 28-06-2013 Sala de Conferências do Pólo da Mitra da Universidade de Évora O Workshop Nacional dedicado ao tema “Investigação em Olivicultura e Azeite – Resultados e Aplicações” realizou-se nos dias 27 e 28 de junho de 2013. Pretendeu-se com este evento, dirigido a produtores, técnicos, e todos os interessados, divulgar os resultados obtidos no âmbito de projetos de investigação em curso em Portugal na área da Olivicultura e Azeite, com especial ênfase nas potenciais aplicações e contribuições para o desenvolvimento do setor. As sessões incidiram nos seguintes temas Sistemas e Técnicas Culturais Recursos Genéticos e Melhoramento Proteção Fitossanitária Tecnologia e Qualidade do Azeite Apresentações Tema 1 - Sistemas e Técnicas Culturais Múltiplos olhares sobre a transpiração do olival - Francisco Lúcio dos Santos Gestão de cobertos vegetais de leguminosas anuais de ressementeira natural em olival - Manuel Ângelo Rodrigues Mecanização do Olival - soluções e novos desafios - Arlindo de Almeida Máquina para a Colheita em Contínuo de Azeitona - António Bento Dias Influência de diferentes regimes hídricos no uso e na eficiência do uso da água, produção e qualidade do azeite - Anabela Silva Medidas de prevenção e mitigação dos impactos da seca no olival de sequeiro: efeitos da rega sustentável e de coberturas vegetais - Eunice Bacelar Contribuição do COTR para o uso eficiente da água na rega do olival - Luís Boteta Tema 2 - Recursos Genéticos e Melhoramentos A diversidade genética da mosca-da-azeitona na bacia mediterrânica - Luís Teixeira Evolução dos primeiros estados fenológicos em oliveira - diversidade intervarietal e alterações climáticas - António Cordeiro Variabilidade genética e química - implicações na rastreabilidade de azeites - Paula Lopes Tema 3 - Protecção Fitossanitária A elevada incidência de vírus em olivais nacionais: causas e consequências - Rosário Félix Como proceder para fertilizar racionalmente o olival - Pedro Jordão Avaliação de Genótipos de Olea europaea vs Infecção de Colletotrichum acutatum - Teresa Carvalho Isolamento e seleção de fungos endofíticos da oliveira para luta biológica contra Colletotrichum acutatum e Verticillium dahliae - Paula Batista A utilização de indicadores biológicos como ferramentas para avaliar o impacte de práticas agrícolas na sustentabilidade do olival - Sónia Santos Proteção contra pragas da oliveira: fomento da ação dos inimigos naturais pelo estabelecimento da flora autóctone - Albino Bento Fungos entomopatogénicos em pragas da oliveira: isolamento, caracterização e selecção para controlo biológico - Paula Batista Tema 4 - Tecnologia e Qualidade Redefinição da Denominação de Origem Protegida “Azeite de Trás-os-Montes” e criação da Denominação de Origem Protegida “Azeite do Douro” - Ricardo Malheiro Azeitonas de mesa do nordeste de Portugal - contributo para a sua caraterização e promoção - Nuno Rodrigues ÁCIDOS GORDOS E POLIFENÓIS EM AZEITE VIRGEM - Isabel Baer Influência da rega na produção e qualidade de azeites produzidos em olivais intensivos (cv. Cobrançosa) e em olivais em sebe (cv. Arbequina) - Mariana Mota Efeito do processamento culinário na composição nutricional e química de azeites portugueses - Susana Casal A Arte do Azeite - Ana Carrilho O Azeite Português na Economia Global: Oportunidades e desafios - Teresa Zacarias Comissão Organizadora: Adélia Sousa, Grupo ASC do ICAAM António Bento Dias, Grupo CTV do ICAAM Fernando Rei, Grupo CTV do ICAAM Francisco Lúcio dos Santos, Grupo ASC do ICAAM-coordenador Raquel Garcia, Grupo CTV do ICAAM Renato Coelho, Grupo CTV do ICAAM Joana Perdigão, UDIT-ICAA

Endemic Angiostrongyliasis, Rio de Janeiro, Brazil

Submitted by Sandra Infurna ([email protected]) on 2016-10-06T12:58:28Z No. of bitstreams: 1 fernando_monteiro_etal_IOC_2011.pdf: 214467 bytes, checksum: 7938fea29a355143991cd4f518b2d970 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2016-10-06T13:12:13Z (GMT) No. of bitstreams: 1 fernando_monteiro_etal_IOC_2011.pdf: 214467 bytes, checksum: 7938fea29a355143991cd4f518b2d970 (MD5)Made available in DSpace on 2016-10-06T13:12:13Z (GMT). No. of bitstreams: 1 fernando_monteiro_etal_IOC_2011.pdf: 214467 bytes, checksum: 7938fea29a355143991cd4f518b2d970 (MD5) Previous issue date: 2011Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil / Universidade Federal Rural do Rio de Janeiro. Seropédica, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.Universidade Federal Rural do Rio de Janeiro. Seropédica, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil

Stability and quasi-normal modes of charged black holes in Born-Infeld gravity

In this paper we study the stability and quasi-normal modes of scalar perturbations of black holes. The static charged black hole considered here is a solution to Born-Infeld electrodynamics coupled to gravity. We conclude that the black hole is stable. We also compare the stability of it with its linear counter-part Reissner-Nordstrom black hole. The quasi-normal modes are computed using the WKB method. The behavior of these modes with the non-linear parameter, temperature, mass of the scalar field and the spherical index are analyzed in detail.Comment: Latex, 17 pages, 13 figures, some sections edited, references adde

Covalent organic frameworks as catalyst support: A case study of thermal, hydrothermal, and mechanical pressure stability of β-ketoenamine-linked TpBD-Me2

Covalent organic frameworks (COFs) are crystalline, ordered networks, that, due to their high surface areas and the opportunity for periodic placement of catalytically active sites, are interesting materials for catalysis. Despite the great interest in the use of COFs for this application, there is currently a lack of fundamental understanding on how catalytically relevant conditions affect the integrity of the materials. To gain insight into the stability of COFs as catalyst supports, we herein subjected a β-ketoenamine-linked COF to thermal treatment at high temperatures, to autogenous pressure in water at different temperatures, and to mechanical pressure during pelletizing, after which the materials were thoroughly characterized to gain insight into the structural changes occurring during these catalytically relevant treatments. The COF was largely stable under all hydrothermal conditions studied, highlighting the applicability of β-ketoenamine-linked COFs under aqueous and vapor conditions. On the other hand, thermal and pressure treatments led to a rapid decline in the surface area already at the lowest temperatures and pressures studied. Theoretical calculations indicated this loss to stem from interlayer rearrangement or buckling of the COF layers induced by the applied conditions. This study demonstrates the suitability of β-ketoenamine-linked COFs for use under hydrothermal conditions, and sheds light on the degradation pathways under thermal and pressure treatments, opening the path to the design of COFs with increased stability under such conditions.Fundação para a Ciência e a Tecnologia | Ref. UTA-EXPL/NPN/0055/2019Fundação para a Ciência e a Tecnologia | Ref. PTDC/QUI-OUT/2095/2021Fundação para a Ciência e a Tecnologia | Ref. PTDC/EQU-EQU/1707/2020Agencia Estatal de Investigación | Ref. RYC2020-030414-IUniversidade de Vigo/CISU

Micromorphology and fatty acid composition of the cypselae of Xeranthemum cylindraceum Sm. (Asteraceae, Cardueae)

The paper presents micromorphology of the cypselae of Xeranthemum cylindraceum as revealed by scanning electron microscopy (SEM) and their fatty acid composition as determined on a gas chromatograph coupled with a flame ionisation detector (GC-FID). The cypselae are densely hairy, straight, ribbed, narrowly obconical to obovoid. Micromorphological features are as follows: striate-rugose surface; adaxial detachment area; asymmetrical carpopodium; presence of biseriate, nonglandular, shortly forked twin hairs; and absence of a pericarp crown. The pappus is paleaceous, homomorphic, uniseriate, persistent, and with several wide, scarious, subulate, and apically pinnulate bristles of variable length. Out of 12 fatty acids detected, nine (88.57%) are identified, ranging from palmitoleic (C16:1) to behenic (C22:0) acids. Oleic acid is dominant (55.24%). Unsaturated fatty acids are predominant in the oil (75.02%). The composition of fatty acids in cypselae of the given species is here reported for the first time. The taxonomic value of the analysed characters is briefly discusse

Thermodynamic analysis of black hole solutions in gravitating nonlinear electrodynamics

We perform a general study of the thermodynamic properties of static electrically charged black hole solutions of nonlinear electrodynamics minimally coupled to gravitation in three space dimensions. The Lagrangian densities governing the dynamics of these models in flat space are defined as arbitrary functions of the gauge field invariants, constrained by some requirements for physical admissibility. The exhaustive classification of these theories in flat space, in terms of the behaviour of the Lagrangian densities in vacuum and on the boundary of their domain of definition, defines twelve families of admissible models. When these models are coupled to gravity, the flat space classification leads to a complete characterization of the associated sets of gravitating electrostatic spherically symmetric solutions by their central and asymptotic behaviours. We focus on nine of these families, which support asymptotically Schwarzschild-like black hole configurations, for which the thermodynamic analysis is possible and pertinent. In this way, the thermodynamic laws are extended to the sets of black hole solutions of these families, for which the generic behaviours of the relevant state variables are classified and thoroughly analyzed in terms of the aforementioned boundary properties of the Lagrangians. Moreover, we find universal scaling laws (which hold and are the same for all the black hole solutions of models belonging to any of the nine families) running the thermodynamic variables with the electric charge and the horizon radius. These scale transformations form a one-parameter multiplicative group, leading to universal "renormalization group"-like first-order differential equations. The beams of characteristics of these equations generate the full set of black hole states associated to any of these gravitating nonlinear electrodynamics...Comment: 51 single column pages, 19 postscript figures, 2 tables, GRG tex style; minor corrections added; final version appearing in General Relativity and Gravitatio

Warped Tachyonic Inflation in Type IIB Flux Compactifications and the Open-String Completeness Conjecture

We consider a cosmological scenario within the KKLT framework for moduli stabilization in string theory. The universal open string tachyon of decaying non-BPS D-brane configurations is proposed to drive eternal topological inflation. Flux-induced `warping' can provide the small slow-roll parameters needed for successful inflation. Constraints on the parameter space leading to sufficient number of e-folds, exit from inflation, density perturbations and stabilization of the Kahler modulus are investigated. The conditions are difficult to satisfy in Klebanov-Strassler throats but can be satisfied in T^3 fibrations and other generic Calabi-Yau manifolds. This requires large volume and magnetic fluxes on the D-brane. The end of inflation may or may not lead to cosmic strings depending on the original non-BPS configuration. A careful investigation of initial conditions leading to a phenomenologically viable model for inflation is carried out. The initial conditions are chosen on the basis of Sen's open string completeness conjecture. We find time symmetrical bounce solutions without initial singularities for k=1 FRW models which are correlated with an inflationary period. Singular big-bang/big-crunch solutions also exist but do not lead to inflation. There is an intriguing correlation between having an inflationary universe in 4 dimensions and 6 compact dimensions or a big-crunch singularity and decompactification.Comment: 43 pages, 9 figures. v3: Typos correcte