Nematosporaceae (Hemiascomycetidae) : taxonomy, pathogenicity, distribution, and vector relations /

Includes bibliographical references (p. 61-71).

Methods for sampling and assessing deposits of insecticidal sprays released over forests /

Issued Nov. 1978.

Radio handbook for extension workers /

"February 1946."

Planning your farmstead wiring and lighting.

Mode of access: Internet.

USDA films for television /

"This publication supersedes Agricultural handbook, no. 131, Television film catalog of the U.S. Department of Agriculture."

Studies of airplane spray-deposit patterns at low flight levels,

Mode of access: Internet.

Circular.

Mode of access: Internet.

Extension circular.

Mode of access: Internet.

Bulletin.

Mode of access: Internet.

Bulletin.

Nos. 1- comprise the service's 1st Annual report of cooperative extension work in agriculture and home economics, 1914/15.

Cooperative Extension Work

Title Varies: a Report on the Receipts, Expenditures, and Results of Cooperative Extension Work In Agriculture and Home Economics In the U.S; Cooperative Extension Work In Agriculture and Home Economics; Report on Cooperative Extension Work In Agriculture and Home Economics

Annual report

1941/42-1954/55 have also special titles: 1941/42, Agricultural research in Louisiana; 1942/43, Progress through agricultural research; 1943/44-1954/55 Research in agriculture.

"Empezar es haber andado la mitad" : Organización social y condiciones laborales en la Sociedad Vitícola Uruguaya

La Sociedad Vitícola Uruguaya (SVU) se fundó en marzo de 1887 fue parte del proyecto modernizador y diversificador del agro uruguayo impulsado por la Asociación Rural del Uruguay (ARU), entidad corporativa similar a la Sociedad Rural Argentina. Este trabajo analiza los orígenes de la SVU, única entidad de este tipo en Sudamérica, en el marco del desarrollo agrario uruguayo de finales del siglo XIX. También se estudian las condiciones de la mano de obra asalariada, la división de las tareas y la estructura organizacional en los orígenes del establecimiento. El objetivo es analizar cómo un sector de la élite uruguaya, reunida en la ARU, impulsó la creación de la SVU como parte de un modelo de producción capitalista diversificada y basada en una sociedad por acciones en el agro a finales del siglo XIX. La hipótesis que guía este trabajo es que dicho proyecto no sólo tenía como objetivo el desarrollo de la vitivinicultura, sino también, el de servir de modelo sociocultural con el fin de motorizar relaciones sociales capitalistas en el agro y de afincar al "gaucho" en el entorno rural

Neutron-mapping polymer flow: Scattering, flow visualization, and molecular theory

Flows of complex fluids need to be understood at both macroscopic and molecular scales, because it is the macroscopic response that controls the fluid behavior, but the molecular scale that ultimately gives rise to rheological and solid-state properties. Here the flow field of an entangled polymer melt through an extended contraction, typical of many polymer processes, is imaged optically and by small-angle neutron scattering. The dual-probe technique samples both the macroscopic stress field in the flow and the microscopic configuration of the polymer molecules at selected points. The results are compared with a recent tube model molecular theory of entangled melt flow that is able to calculate both the stress and the single-chain structure factor from first principles. The combined action of the three fundamental entangled processes of reptation, contour length fluctuation, and convective constraint release is essential to account quantitatively for the rich rheological behavior. The multiscale approach unearths a new feature: Orientation at the length scale of the entire chain decays considerably more slowly than at the smaller entanglement length.

Phototoxicity of photosystem II (PSII) herbicides to coral

Recent reports of contamination of the Great Barrier Reef Marine Park by herbicides used in antifouling paints and in agriculture have caused concern over the possible effects on corals in nearshore areas. Pulse-Amplitude Modulated (PAM) chlorophyll fluorescence techniques were used to examine changes in the maximum effective quantum yield (ΔF/Fm′) of symbiotic dinoflagellates within the host tissues (in hospite) of the coral Seriatopora hystrix exposed to a number of Photosystem II (PSII) inhibiting herbicides in short-term toxicity tests. The concentration of herbicide required to reduce ΔF/Fm′ by 50% (median effective concentration [EC50]) differed by over 2 orders of magnitude: Irgarol 1051 (0.7 μg l-1) > ametryn (1.7 μg l-1) > diuron (2.3 μg l-1) > hexazinone (8.8 μg l -1) > atrazine (45 μg l-1) > simazine (150 μg l-1) > tebuthiuron (175 μg l-1) > ionynil (> 1 mg l-1). Similar absolute and relative toxicities were observed with colonies of the coral Acropora formosa (Irgarol 1051 EC50: 1.3 μg l-1, diuron EC50: 2.8 μg l-1), Time-course experiments indicated that ΔF/Fm′ was rapidly reduced (i.e. within minutes) in S. hystrix exposed to Irgarol 1051 and diuron. On return to fresh running seawater, ΔF/Fm′ recovered quickly in diuron-exposed corals (i.e. in minutes to hours), but slowly in corals exposed to Irgarol 1051 (i.e. hours to days). Time-course experiments indicated that the effects of diuron (3 μg l-1) on S. hystrix were inversely related to temperature over the range 20 to 30 °C, although initially the effects were less at the lower temperatures. Repeated exposure to pulses of Irgarol 1051 (daily 2 h exposure to 30 μg l -1 over 4 d) resulted in a 30% decrease in the density of symbiotic dinoflagellates in the tissues of S. hystrix.