A review of the tribes of Deltocephalinae (Hemiptera: Auchenorrhyncha: Cicadellidae)

The classification of the largest subfamily of leafhoppers, Deltocephalinae, including 38 tribes, 923 genera, and 6683 valid species, is reviewed and revised. An updated phylogeny of the subfamily based on molecular (28S, Histone H3) and morphological data and an expanded taxon sample (37 taxa not included in previous analyses) is presented. Based on the results of these analyses and on the morphological examination of many representatives of the subfamily, the classification of the tribes and subtribes of Deltocephalinae is revised. Complete morphological descriptions, illustrations, lists of the included genera, and notes on their distribution, ecology, and important vector species are provided for the 38 recognized tribes and 18 subtribes. A dichotomous key to the tribes is provided. All names in the taxonomic treatments are hyperlinked to online resources for individual taxa which are supported by a comprehensive database for Deltocephalinae compiled using the taxonomic database software package 3I. The online functionality includes an interactive key to tribes and subtribes and advanced database searching options. Each taxon (subspecies through subfamily) has a unique taxon webpage providing nomenclatural information, lists of included taxa, an automated description (if available), images (if available), distributional information, bibliographic references and links to outside resources. Some observations and trends regarding the history of taxonomic descriptions in Deltocephalinae are reported. Four new tribes are described: Bahitini tribe nov. (25 genera), Bonsapeiini tribe nov. (21 genera), Phlepsiini tribe nov. (4 genera), and Vartini tribe nov. (7 genera). The circumscription and morphological characterization of Scaphoideini Oman, 1943 (61 genera) is substantially revised. Eleven new species are described: Acostemma stilleri sp. nov., Arrugada linnavuorii sp. nov., Drabescus zhangi sp. nov., Parabolopona webbi sp. nov., Goniagnathus emeljanovi sp. nov., Hecalus hamiltoni sp. nov., Scaphoideus omani sp. nov., Dwightla delongi sp. nov., Abimwa knighti sp. nov., Gannia viraktamathi sp. nov., and Doratulina dmitrievi sp. nov. Some family-group level taxonomic changes are made: Platymetopiini Haupt, 1929, Anoterostemmini Haupt, 1929, and Allygidiina Dmitriev, 2006 are synonymized with Athysanini Van Duzee, 1892, syn. nov.; Procepitini Dmitriev, 2002 is synonymized with Cicadulini Van Duzee, 1892, syn. nov.; Listrophorini Boulard, 1971 is synonymized with Chiasmini Distant, 1908, syn. nov.; Adamini Linnavuori & Al-Ne’amy, 1983, Dwightlini McKamey, 2003, and Ianeirini Linnavuori, 1978 are synonymized with Selenocephalini Fieber, 1872 syn.nov., and all three are now recognized as valid subtribes in their parent tribe. New placements of many genera to tribe and subtribe are made, and these are described in individual taxon treatments

THE EUROPEAN UNION’S FRAMEWORK FOR CLIMATE CHANGE ADAPTATION: IMPLICATIONS OF AGRICULTURE’S ADAPTATION THROUGH SUSTAINED YIELD GROWTH

Agricultural and Food Policy, Environmental Economics and Policy, Resource /Energy Economics and Policy,

A measurement of the vibrational band strength for the upsilon sub 3 band of the HO2 radical

The HO2 radicals generated in a discharge-flow system were observed with tunable diode laser absorption in the P-branch of the nu(3) vibrationall band at 1080/cm. The observed line positions agree with those calculated from the molecular constants for the nu(3) bland obtained from a previous study using laser magnetic resonance spectroscopy. The band strength was determined by observing line center absoptions when HO2 is produced in the reaction F + H2O2 yields HO2 + HF (k1) with a measured concentration of atomic fluorine and excess hydrogen peroxide. F-atom concentrations are measured by diode laser absorption of the spin-orbit transition at 404/cm. The analysis accounts for HO2 losses due to the reactions of HO2 + HO2 yields H2O2 + O2 (k3) and F + HO2 yields HF + O2 (k4). The line strength for the 6(15) 7(16) F(1) transition is 2.9 x 10 to the 21st power sq cm/molecule/cm which corresponds to a nu(3) band strength of 34 +/- 9 sq/cm(STP atm). This value is a factor of 6 lower than previous ab initio calculations. These results will be useful in assessing the feasibility of atmospheric measurements of HO2 using infrared absorption techniques

THE MEXICAN HOG INDUSTRY: MOVING BEYOND 2003

The purpose of this paper is to show how Mexican hog producers can take advantage of NAFTA in order to increase their competitiveness. In particular, lowering feed costs, improving transportation facilities, and establishing greater control over swine diseases would go a long way towards increasing the competitiveness of Mexican producers.Livestock Production/Industries,

Agricultural Employment Patterns of Immigrant Workers in the United States

Despite of the important role international migration fills in the United States’ labor-intensive agricultural sector, few studies have addressed the individual characteristics and circumstances surrounding entry and exit by farm laborers. With increasing public attention on international migrant labor, policymakers have a need to understand the labor market patterns of these workers if they are to formulate appropriate immigration reforms, including temporary worker programs geared towards agriculture. In this analysis, we model the likelihood of entering agricultural employment by migrants to the United States. Using data from the Mexican Migration Project we find that migrants with higher levels of education and a greater command of English are less likely to work as agricultural laborers. Those that do enter agricultural occupation stay in the United States for shorter periods of time per trip than those who enter non-agricultural occupation. In future analysis we will attempt to model the demand for agricultural farm work as a determinant of the decision by migrants to enter the U.S. market for hired farm labor.Agricultural Employment, Mexican Migration, Occupational Choice, Agribusiness, Agricultural and Food Policy, Farm Management, International Relations/Trade, Labor and Human Capital, Production Economics,

NORTH AMERICAN AGRICULTURAL TRADE DURING 1975-98: A BACKGROUND PAPER ON TRADE FLOWS

International Relations/Trade,

Instabilities of rotating jets

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.Includes bibliographical references (p. 33-34).When a jet of water is in free fall, it rapidly breaks up into drops, since a cylinder of water is unstable. This and other problems involving the form of a volume of water bound by surface tension have yielded a wealth of theoretical and experimental results, and given insight into such phenomena as the shape of the Earth. Particularly interesting behaviors tend to emerge when the fluid in question is rotating; a drop may, for example, form a toroidal or ellipsoidal shape or even stretch out into some multi-lobed, non-axisymmetric form. In this paper, we investigate the properties of a rotating jet of water, and determine what regime of the parameter space are dominated by the various forms of instability. This is both predicted theoretically and demonstrated to be accurate experimentally. If we watch a jet of water as the rotation rate is gradually increased from zero, the drop size will start shrinking gradually, and then suddenly, rather than a single row of drops, we will see the jet breaking up into two-lobed, bar shaped forms, like the rung of a ladder. The point at which this transition occurs is characterized in terms of the rotational Bond number, B₀ = ... . The critical B₀ may be as low as 6, if there is a strong bias imparted by vibration of the table at an appropriate frequency, but for a perfectly quiescent rotating jet the second mode does not become dominant until a higher B₀. As the rotation rate is increased above this, the instability grows gradually more dramatic, and eventually the two lobes of each drop are breaking apart and flying outward. Then a transition to a third mode will occur, with three lobes in each drop; this is possible from a B₀ of 12, and dominant above a B₀ slightly higher than that. In general, mode m may occur whenever(cont.) B₀ > m(m + 1).by Russell Zahniser.S.B

NORTH AMERICAN INTEGRATION IN AGRICULTURE: A SURVEY PAPER

This paper surveys the economic literature about North American integration in the agri-food sector. The purpose of this survey is two-fold: it summarizes the lessons learned, and it identifies areas where further research could provide valuable input into policy discussions. As the integration of North American agriculture progresses, the range of agri-food policies with strictly domestic effects becomes increasingly narrow. Thus, policymakers in North America need to consider the effects that their decisions will have on other NAFTA countries, as well as the impact that decisions by other NAFTA governments will have at home. The paper is organized as follows. Section 2 identifies the major factors contributing to integration and comments on their relative importance. Section 3 summarizes research into the indicators of integration. These studies focus on price co-movements and trade flow data. Section 4 outlines the state of current knowledge regarding foreign direct investment in the agri-food sector, while Section 5 assesses the impact of integration on the structure and performance of the sector. Section 6 discusses opportunities for further integration in the sector, and Section 7 concludes the paper. Throughout the paper, gaps in the knowledge base are highlighted, along with suggested areas for further research.Industrial Organization,

Competiveness of Latin American Exports in the U.S. Banana Market

U.S. banana demand differentiated by country of origin is estimated using the generalized dynamic Rotterdam model. Results indicate that dynamic factors play a significant role in determining the allocation of U.S. banana expenditures across exporting sources. Of particular interest is Guatemala’s increased share and Costa Rica’s decreased share of U.S. banana supply. A number of factors explained why Guatemala replaced Costa Rica as the leading U.S. supplier in 2007. (1) Guatemala is the least expensive source on average. (2) Habit persistence, adjustment costs, and other dynamic factors favor Guatemala’s exports. (3) Given increases in the relative price of Costa Rica’s bananas, the price competition between Costa Rica and Guatemala is highly significant. (4) Bananas from Costa Rica are highly responsive to own-price while imports from Guatemala are more price-inelastic. (5) Heavy rains and fluctuating temperatures in Costa Rica have decreased banana production and exports.bananas, imports, demand, Latin America, United States, Demand and Price Analysis, International Relations/Trade, F14, Q11, Q13, Q17,

STRUCTURAL CHANGE IN AN ERA OF INCREASED OPENNESS: A BACKGROUND PAPER ON THE STRUCTURE OF U.S. AGRICULTURE

Agribusiness,