Biological Control of Giant Reed (Arundo donax): Economic Aspects

Arundo donax is a large, invasive weed consuming large quantities of water in the riparian area of the Texas Rio Grande Basin. With water availability a concern to the area, the USDA-ARS is investigating biological control agents to increase available water, creating a benefit to both the region’s economy and society in general.Arundo donax, Giant Reed, Water, Economics, Invasive, Environmental Economics and Policy, Resource /Energy Economics and Policy,

Variaciones en los patrones de pigmentación y de color de larvas de poblaciones naturales de anofeles albimanus de Colombia

Color and pigmentation variants of Anopheles albimanus of third and fourth instar larvae were described from field populations in four different geogaphic and ecological areas in Colombia, together with their frecuency. These variants include three of the head capsule, nine of body pigmentation and of body color. Also, curved antennal sabers and antennal pigmentation are described. We report the ocurrence of high level of polymorphys in body color, pigmentation pattern and other visible traits. A brief description of each variant its frequency in each populations is included.Fueron observados el patrón de pigmentación y el color del cuerpo de las larvas de III y IV estadio en poblaciones naturales de Anopheles albimanus procedentes de cuatro áreas geográficas y ecológicas diferentes. Se incluyen tres variantes de la cápsula de la cabeza, el sable curvado de las antenas y la pigmentación; nueve variantes de la pigmentación del cuerpo y 17 del color del cuerpo. Se informa la alta variación en los patrones de color y otras características visibles. Se incluye una breve descripción de cada variante y la frecuencia observada en cada población

Exploring Entrepreneurial Cognition in Franchisees: A Knowledge-Structure Approach

ABSTRACT Franchisees participate in new business creation uniquely, because, in many respects, the development of their ventures is under the direction of franchisors. In this study, using entrepreneurial scripts, we compare the extent to which franchisee venturing is similar to and/ or distinct from individual-based entrepreneurship in non-franchise new ventures. We therefore examined the entrepreneurial scripts of individuals in a purposeful sample of 54 franchisees compared to two counterpart groups: 54 independent entrepreneurs and 94 managers (neither franchisee nor entrepreneur). Using MANCOVA and follow-up tests we find that franchisees are less like entrepreneurs and more similar to non-entrepreneur managers

Exploring Entrepreneurial Cognition in Franchisees: A Knowledge-Structure Approach

Franchisees participate in new business creation uniquely, because, in many respects, the development of their ventures is under the direction of franchisors. In this study, using entrepreneurial scripts, we compare the extent to which franchisee venturing is similar to and/or distinct from individual-based entrepreneurship in nonfranchise new ventures. We therefore examined the entrepreneurial scripts of individuals in a purposeful sample of 54 franchisees compared to two counterpart groups: 54 independent entrepreneurs and 94 managers (neither franchisee nor entrepreneur). Using MANCOVA and follow-up tests we find that franchisees are less like entrepreneurs and more similar to nonentrepreneur managers

Occupational and environmental hazard assessments for the isolation, purification and toxicity testing of cyanobacterial toxins

Cyanobacteria can produce groups of structurally and functionally unrelated but highly potent toxins. Cyanotoxins are used in multiple research endeavours, either for direct investigation of their toxicologic properties, or as functional analogues for various biochemical and physiological processes. This paper presents occupational safety guidelines and recommendations for personnel working in field, laboratory or industrial settings to produce and use purified cyanotoxins and toxic cyanobacteria, from bulk harvesting of bloom material, mass culture of laboratory isolates, through routine extraction, isolation and purification. Oral, inhalational, dermal and parenteral routes are all potential occupational exposure pathways during the various stages of cyanotoxin production and application. Investigation of toxicologic or pharmacologic properties using in vivo models may present specific risks if radiolabelled cyanotoxins are employed, and the potential for occupational exposure via the dermal route is heightened with the use of organic solvents as vehicles. Inter- and intra-national transport of living cyanobacteria for research purposes risks establishing feral microalgal populations, so disinfection of culture equipment and destruction of cells by autoclaving, incineration and/or chlorination is recommended in order to prevent viable cyanobacteria from escaping research or production facilities

Economies of Size in Municipal Water-Treatment Technologies: A Texas Lower Rio Grande Valley Case Study

As the U.S. population continues to increase, the priority on planning for future water quantity and quality becomes more important. Historically, many municipalities have primarily relied upon surface water as their major source of drinking water. In recent years, however, technological advancements have improved the economic viability of reverse-osmosis (RO) desalination of brackish-groundwater as a potable water source. By including brackishgroundwater, there may be an alternative water source that provides municipalities an opportunity to hedge against droughts, political shortfalls, and protection from potential surfacewater contamination. In addition to selecting a water-treatment technology, municipalities and their associated water planners must determine the appropriate facility size, location, etc. To assist in these issues, this research investigates and reports on economies of size for both conventional surface-water treatment and brackish-groundwater desalination by using results from four water-treatment facilities in the Texas Lower Rio Grande Valley (LRGV). The methodology and associated results herein may have direct implications on future water planning as highlighting the most economically-efficient alternative(s) is a key objective. In this study, economic and financial life-cycle costs are calculated for a “small” conventional surface-water facility (i.e., 2.0 million gallons per day (mgd) Olmito facility) and a “small” brackish-groundwater desalination facility (i.e., 1.13 mgd La Sara facility). Thereafter, these results are merged with other, prior life-cycle cost analyses’ results for a “medium” conventional surface-water facility (i.e., 8.25 mgd McAllen Northwest facility) and a “medium” brackish-groundwater desalination facility (i.e., 7.5 mgd Southmost facility). The combined data allow for examination of any apparent economies of size amongst the conventional surface-water facilities and the brackish-groundwater desalination facilities. This research utilized the CITY H20 ECONOMICS and the DESAL ECONOMICS © © Excel® spreadsheet models developed by agricultural economists with Texas AgriLife Research and Texas AgriLife Extension Service. The life-cycle costs calculated within these spreadsheet models provide input for work which subsequently provides the estimations of economies of size. Although the economies of size results are only based on four facilities and are only applicable to the Texas LRGV, the results are nonetheless useful. In short, it is determined that economies of size are apparent in conventional surface-water treatment and constant economies of size are apparent in brackish-groundwater desalination. Further, based on modified life-cycle costs (which seek to more-precisely compare across water-treatment technologies and/or facilities), this research also concludes that reverse-osmosis (RO) desalination of brackish-groundwater is economically competitive with conventional surface-water treatment in this region

Reassessing Britain’s ‘post-war consensus’: the politics of reason 1945–1979

Since the late-1970s, scholars have been engaged in a vibrant debate about the nature of post-war British politics. While some writers have suggested that the three decades that succeeded the Second World War witnessed a bi-partisan consensus on key policy questions, others have argued that it was conflict, not agreement, that marked the period. This article offers a novel contribution to this controversy by drawing attention to the epistemological beliefs of the Labour and Conservative parties. It argues that once these beliefs are considered, it becomes possible to reconcile some of the competing claims made by proponents and critics of the ‘post-war consensus’ thesis. Labour and Conservative leaders may have been wedded to different beliefs, but they also shared a common enthusiasm for empiricist reasoning and were both reluctant to identify fixed political ‘ends’ that they sought to realise. Consequently, they were both committed to evolutionary forms of change, and they eschewed the notion that any social or political arrangement was of universal value

Linking Oviposition Site Choice to Offspring Fitness in Aedes aegypti: Consequences for Targeted Larval Control of Dengue Vectors

Controlling the mosquito Aedes aegypti, the predominant dengue vector, requires understanding the ecological and behavioral factors that influence population abundance. Females of several mosquito species are able to identify high-quality egg-laying sites, resulting in enhanced offspring development and survival, and ultimately promoting population growth. Here, the authors investigated egg-laying decisions of Ae. aegypti. Paradoxically, they found that larval survival and development were poorest in the containers females most often selected for egg deposition. Thus, egg-laying decisions may contribute to crowding of larvae and play a role in regulating mosquito populations. The authors also tested whether removal of the containers producing the most adult mosquitoes, a World Health Organization-recommended dengue prevention strategy, changes the pattern of how females allocate their eggs. Elimination of the most productive containers led to a more even distribution of eggs in one trial, but not another. These results suggest that behavioral adjustments by egg-laying females may lessen the effectiveness of a common mosquito control tactic. The authors advocate incorporating control strategies that take advantage of the natural egg-laying preferences of this vector species, such as luring egg-laying females to traps or places where their eggs will accumulate, but not develop

Oviposition Site Selection by the Dengue Vector Aedes aegypti and Its Implications for Dengue Control

Controlling the mosquito Aedes aegypti is of public health importance because, at present, it is the only means to stop dengue virus transmission. Implementing successful mosquito control programs requires understanding what factors regulate population abundance, as well as anticipating how mosquitoes may adapt to control measures. In some species of mosquitoes, females choose egg-laying sites to improve the survival and growth of their offspring, a behavior that ultimately influences population distribution and abundance. In the current study, we tested whether Ae. aegypti actively choose the containers in which they lay their eggs and determined what cues are most relevant to that process. We also explored whether females select containers that provide the most food for their larval progeny. Surprisingly, egg-laying females were most attracted to sites containing other immature Ae. aegypti, rather than to sites containing the most food. We propose that this behavior may contribute to density-dependent competition for food among larvae and play a larger role than previously thought in regulating Ae. aegypti populations. We recommend that accounting for, and even taking advantage of, this natural behavior will lead to more effective strategies for dengue prevention