8,178 research outputs found
Pollinator shortage and global crop yield
No full textFil: Garibaldi, Lucas Alejandro. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono; Argentina.Fil: Aizen, Marcelo A. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono; Argentina.Fil: Cunningham, Saul A. CSIRO Entomology; Australia.Fil: Klein, Alexandra M. University of California; USA.Fil: Klein, Alexandra M. University of Goettingen; Alemania.Fil: Aizen, Marcelo A. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Fil: Aizen, Marcelo A. Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA); Argentina.Fil: Garibaldi, Lucas Alejandro. Universidad de Buenos Aires (UBA). Facultad de Agronomía; Argentina.A pollinator decline caused by environmental degradation might be compromising the production of pollinator-dependent crops. In a recent article, we compared 45 year series (1961–2006) in yield, production, and cultivated area of pollinator-dependent and nondependent crop around the world. If pollinator shortage is occurring globally, we expected a lower annual growth rate in yield for pollinator-dependent than nondependent crops, but a higher growth in cultivated area to compensate the lower yield. We have found little evidence for the first “yield” prediction but strong evidence for the second “area” prediction. Here, we present an additional analysis to show that the first and second predictions are both supported for crops that vary in dependency levels from nondependent to moderate dependence (i.e. up to 65% average yield reduction without pollinators). However, those crops for which animal pollination is essential (i.e. 95% average yield reduction without pollinators) showed higher growth in yield and lower expansion in area than expected in a pollination shortage scenario. We propose that pollination management for highly pollinator-dependent crops, such us renting hives or hand pollination, might have compensated for pollinator limitation of yield
How much does agriculture depend on pollinators? Lessons from long-term trends in crop production
No full textFil: Aizen, Marcelo A. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono; Argentina.Fil: Garibaldi, Lucas Alejandro. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio Ecotono; Argentina.Fil: Cunningham, Saul A. CSIRO Entomology; Australia.Fil: Klein, Alexandra M. University of California; USA.Fil: Aizen, Marcelo A. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Fil: Aizen, Marcelo A. Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA); Argentina.Fil: Garibaldi, Lucas Alejandro. Universidad de Buenos Aires (UBA). Facultad de Agronomía; Argentina.Fil: Klein, Alexandra M. University of Goettingen; Alemania.Abstract
Background and Aims
Productivity of many crops benefits from the presence of pollinating insects, so a decline in pollinator abundance should compromise global agricultural production. Motivated by the lack of accurate estimates of the size of this threat, we quantified the effect of total loss of pollinators on global agricultural production and crop production diversity. The change in pollinator dependency over 46 years was also evaluated, considering the developed and developing world separately.
Methods
Using the extensive FAO dataset, yearly data were compiled for 1961–2006 on production and cultivated area of 87 important crops, which we classified into five categories of pollinator dependency. Based on measures of the aggregate effect of differential pollinator dependence, the consequences of a complete loss of pollinators in terms of reductions in total agricultural production and diversity were calculated. An estimate was also made of the increase in total cultivated area that would be required to compensate for the decrease in production of every single crop in the absence of pollinators.
Key Results
The expected direct reduction in total agricultural production in the absence of animal pollination ranged from 3 to 8 %, with smaller impacts on agricultural production diversity. The percentage increase in cultivated area needed to compensate for these deficits was several times higher, particularly in the developing world, which comprises two-thirds of the land devoted to crop cultivation globally. Crops with lower yield growth tended to have undergone greater expansion in cultivated area. Agriculture has become more pollinator-dependent over time, and this trend is more pronounced in the developing than developed world.
Conclusions
We propose that pollination shortage will intensify demand for agricultural land, a trend that will be more pronounced in the developing world. This increasing pressure on supply of agricultural land could significantly contribute to global environmental change
Michael R. Lucas. The Western Alliance after INF. Redefining US Policy Toward Europe and the Soviet Union
No full textKlein. Michael R. Lucas. The Western Alliance after INF. Redefining US Policy Toward Europe and the Soviet Union. In: Politique étrangère, n°4 - 1991 - 56ᵉannée. p. 978
Michael R. Lucas. The Western Alliance after INF. Redefining US Policy Toward Europe and the Soviet Union
No full textKlein. Michael R. Lucas. The Western Alliance after INF. Redefining US Policy Toward Europe and the Soviet Union. In: Politique étrangère, n°4 - 1991 - 56ᵉannée. p. 978
<i>No se sabe</i>: entrevista a Lucas Gagliardi
No full textEntrevista al Licenciado y Profesor en Letras (UNLP) Lucas Gagliardi. Se especializa en literatura en lengua inglesa y en crítica genética. Se desempeña como profesor en la Universidad Pedagógica (UNIPE), en institutos de formación docente y escuelas secundarias. Ha participado en proyectos de investigación sobre archivos de escritores, publicaciones impresas. Participa en el programa de voluntariado universitario de la Facultad de Trabajo Social (UNLP) en articulación con la Biblioteca Ambulante del Hospital de Niños dictando talleres de lectura y escritura.Al hacer clic en el enlace que figura en "Documentos relacionados", pueden accederse a todos los trabajos de Lucas Gagliardi presentes en el repositorio.Radio Universidad Nacional de La Plat
Microfoundations: a decisive dividing line between Keynesian and new classical macroeconomics?
No full textIt is often argued that what marks the difference between Keynesian macroeconomics and new classical macroeconomics (the first installment of dynamic stochastic general equilibrium models) is the presence of microfoundations. These are deemed to be absent in the Keynesian approach, but central to the new classical one. The aim of my paper is to critically discuss this view. Lucas and Sargent defined the microfoundations requirement as consisting of two elements, optimizing behavior and market clearing. I claim that an alternative, weaker, definition is conceivable, which can be traced back to Hayek and Patinkin. According to them, the microfoundations requirement consists of a single criterion, optimizing planning. This definition, I claim, is better than the new classical one. Next, I examine whether Keynesian macroeconomics, which admittedly does not abide by the Lucas-Sargent definition, does accord with the Hayek-Patinkin approach. My conclusion is that Keynes’s General Theory is indeed microfounded in this sense, although no single conclusion can be drawn for Keynesian models in general.microfoundations, Keynes, new classical macroeconomics
From The Keynesian Revolution to the Klein-Goldberger Model: Klein and the Dynamization of Keynesian Theory
No full textAccording to Klein, Keynes’s General Theory was crying out for empirical application. He set himself the task of implementing this extension. Our paper documents the different stages of his endeavor, focusing on his The Keynesian Revolution book, Journal of Political Economy article on aggregate demand theory, and his essay on the empirical foundations of Keynesian theory published in the Post-Keynesian Economics book edited by Kurihara. Klein’s claim is that his empirical model (the Klein-Goldberger model) vindicates Keynes’s theoretical insights, in particular the existence of involuntary unemployment. While praising Klein for having succeeded in making Keynesian theory empirical and dynamic, we argue that he paid a high price for this achievement. Klein and Goldberger’s model is less Keynesian than they claim. In particular, Klein’s claim that it validates the existence of involuntary unemployment does not stand up to close scrutiny.
Gas volume fraction and velocity profiles: vertical and inclined bubbly air-water flows
No full textUpward inclined gas-liquid flows are frequently encountered in the oil industry and data relating to the local gas volume fraction distribution and the local gas velocity distribution is important, for example, in pressure gradient prediction and in modeling oil well 'blowouts'. In this paper measurements are presented of the local gas volume fraction distribution and the local axial gas velocity distribution which were taken in bubbly air-water flows in an 80 mm diameter pipe which was inclined at angles of 0°, 15° and 30° to the vertical. Qualitative arguments are presented to explain the influence of the liquid superficial velocity on the local gas volume fraction distribution in inclined flow and also to explain the very high axial gas velocities observed towards the upper side of the inclined pipe
West Toledo Branch 60th Anniversary, Toledo, Ohio, 1990
No full textFrom the West Toledo Branch Collection, Toledo author Virginia Hannford Eyster poses for a portrait while holding a copy of her book, Journey of the Heart, during the 60th anniversary party of the West Toledo Branch on September 30, 1990. Terms associated with the photograph are: Public libraries | Anniversaries | Celebrations | Toledo-Lucas County Public Library (Toledo, Ohio) | West Toledo Branch (Toledo, Ohio) | 1320 Sylvania Avenue (Toledo, Ohio) | Eyster, Virginia Hannaford | Author
Vernie E. Klein, (1893), purchased by Mrs. Vernie E. Klein on July 18, 1954.
No full textDocuments regarding the double headstone for Vernie E. Klein, (1893), buried with Mrs. Amanda M. Klein, (1891), purchased by Mrs. Vernie E. Klein. The marker was placed at Springfield Twp Cemetery in Holland, Ohio. The stone is made of Barre with Sandblast letters
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