3,158 research outputs found
Biological Pest Controls: Possibilities for Improved Implementation in Iowa
Chemical insecticides are the standard means for reducing populations of insect pests in agricultural and horticultural settings. However, government regulations are restricting the use of a variety of pesticides for many agricultural uses. The requirement of registration for all pesticides labelled before 1984 has already resulted in the cancellation of approximately 20,000 pesticide registrations in 1989. In addition, pest resistance to insecticides (over 400 species), and an increased sensitivity in the general public to possible environmental and health hazards are forcing the agricultural industry to search for alternatives to chemical control
CONSUMER PREFERENCES FOR LOCAL VERSUS OUT-OF-STATE GROWN SELECTED FRESH PRODUCE: THE CASE OF KNOXVILLE, TENNESSEE
Consumer behavior with respect to purchase regularity, satisfaction, origin, and willingness to pay for selected local versus non-Tennessee grown fresh produce is examined. Except for origin, consumer behavior with respect to the above is affected by income, of respondent, college education, and occupation. The pattern of significant variables changed by commodity. Tomatoes, followed by peaches, had the greatest local market potential. Local promotion of other products may be more difficult. Results suggested consumers have no strong preferences for or against locally grown fresh produce. The prices of locally grown commodities in Knoxville should be less than or equal to those of comparable quality non-Tennessee commodities.Consumer/Household Economics,
CONSUMERS' PERCEPTIONS OF LOCALLY GROWN PRODUCE AT RETAIL OUTLETS
Consumer/Household Economics,
Influence of native roadside plants on biological control of Iowa crop pests
Boundaries between cropland and natural plant communities provide food, water, and cover for wildlife. Similarly, field borders com posed of natural plant communities, especially those that include flowering plants, may have a marked effect on natural enemies of crop pests within crop fields. Monoculture crops typical of much of the Midwest do not provide adequate sources of food (nectar, pollen) or shelter and breeding sites for these natural enemies. Nectar and pollen are produced by a variety of native Midwestern plants; as these plants flower in succession throughout the growing season, they provide a continuous food source for the natural enemies (parasites) of pests attacking adjacent crops
Do Beneficial Insect Habitats Also Provide Quality Brood Habitat for Northern Bobwhite?
Strips of fallow vegetation along cropland borders are an effective strategy for providing northern bobwhite (Colinus virginianus) habitat. However, a limitation of fallow borders is the lack of nectar-producing vegetation needed to sustain many beneficial insect populations. Planted borders that contain mixes of prairie flowers and grasses may harbor more diverse arthropod communities, but the relative value of these borders as bobwhite brood habitat compared to fallow borders is unknown. Vegetation composition likely has the largest influence on a field border’s structural characteristics, which consequently may impact bobwhite foraging efficiency. Thus, actively planting field borders may not yield the vegetative composition and structure needed to provide quality brood habitat. We used groups of 6 human-imprinted bobwhite chicks as a bioassay for comparing 4 different field border treatments (planted native warm season grasses (NWSG) and prairie flowers, planted prairie flowers only, fallow vegetation, or mowed vegetation) as brood habitat from June to August 2009 and 2010. All field border treatments (0.33 ha each) were established around 9 organic crop fields. Groups of chicks were led through borders for 30-min foraging trials and immediately euthanized at the end of each trial. Their crops and gizzards were dissected in the laboratory, and eaten arthropods were measured, counted, and identified to taxonomic family. We used allometric equations to estimate the live weight of all arthropods consumed, and to calculate a mean foraging rate (grams of arthropods consumed/ chick/30 min) for each field border treatment. We used a modified leaf blower-vacuum to sample arthropod prey availability and diversity in each field border treatment. Sampled arthropods were counted and identified to taxomomic family. We also calculated a Shannon-Weiner diversity index for each field border treatment. Foraging rate did not differ among border treatments in 2009 or 2010. Similarly, mean arthropod densities and diversity calculated from blower-vac samples did not differ among treatments in 2009 or 2010. Chick foraging rate was relatively high and arthropod prey was abundant even in mowed field borders. We suspect the amount of arthropod prey foods is likely not a limiting factor for bobwhite chicks in uncultivated habitats, rather, vegetative structure that facilitates movement, supports a suitable thermal micro-climate, and provides protection from predators is most important for bobwhite broods. Our results suggest that field borders planted for promoting beneficial insects provide bobwhite brood habitat equivalent to fallow borders. However, beneficial insect habitats are expensive, and require additional time and funding to insure successful establishment. The cost of establishing planted NWSG and prairie flowers and planted prairie flowers only borders in our study was ~ 1,773/ha, respectively. Fallow borders are likely the most cost-effective option for landowners/managers whose primary interest is providing bobwhite habitat
Towards practice-based studies of HRM: an actor-network and communities of practice informed approach
HRM may have become co-terminus with the new managerialism in the rhetorical orthodoxies of the HRM textbooks and other platforms for its professional claims. However, we have detailed case-study data showing that HR practices can be much more complicated, nuanced and indeed resistive toward management within organizational settings.
Our study is based on ethnographic research, informed by actor-network theory and community of practice theory conducted by one of the authors over an 18-month period. Using actor-network theory in a descriptive and critical way, we analyse practices of managerial resistance, enrolment and counter-enrolment through which an unofficial network of managers used a formal HRM practice to successfully counteract the official strategy of the firm, which was to close parts of a production site. As a consequence, this network of middle managers effectively changed top management strategy and did so through official HRM practices, coupled with other actor-network building processes, arguably for the ultimate benefit of the organization, though against the initial views of the top management.
The research reported here, may be characterized as a situated study of HRM-in-practice and we draw conclusions which problematize the concept of HRM in contemporary management literature
Analysis of Carbohydrate Storage Granules in the Diazotrophic Cyanobacterium Cyanothece sp. PCC 7822.
The unicellular diazotrophic cyanobacteria of the genus Cyanothece demonstrate oscillations in nitrogenase activity and H2 production when grown under 12 h light–12 h dark cycles. We established that Cyanothece sp. PCC 7822 allows for the construction of knock-out mutants and our objective was to improve the growth characteristics of this strain and to identify the nature of the intracellular storage granules. We report the physiological and morphological effects of reduction in nitrate and phosphate concentrations in BG-11 media on this strain. We developed a series of BG-11-derived growth media and monitored batch culture growth, nitrogenase activity and nitrogenase-mediated hydrogen production, culture synchronicity, and intracellular storage content. Reduction in NaNO3 and K2HPO4 concentrations from 17.6 and 0.23 to 4.41 and 0.06 mM, respectively, improved growth characteristics such as cell size and uniformity, and enhanced the rate of cell division. Cells grown in this low NP BG-11 were less complex, a parameter that related to the composition of the intracellular storage granules. Cells grown in low NP BG-11 had less polyphosphate, fewer polyhydroxybutyrate granules and many smaller granules became evident. Biochemical analysis and transmission electron microscopy using the histocytochemical PATO technique demonstrated that these small granules contained glycogen. The glycogen levels and the number of granules per cell correlated nicely with a 2.3 to 3.3-fold change from the minimum at L0 to the maximum at D0. The differences in granule morphology and enzymes between Cyanothece ATCC 51142 and CyanothecePCC 7822 provide insights into the formation of large starch-like granules in some cyanobacteria
Acclimation for heat resistance in egg parasitoid Trochogramma exigumm Jhon and Plinto
ABSTRACT In recent years, a total area of over 32 million ha in agriculture and forestry in the world has been treated annually with Trichogramma spp for controlling insect pests. In the world wide use of Trichogramma spp, the former USSR ranked first, followed by China and Mexico. Extensive utilization of this parasitoid was developed for rice, corn, sugarcane, cotton, vegetable and pine. The selection of suitable species, quality parasitoids, reasonable release rate per hectare, climate during release and release methods are the factors that determine the efficiency of Trichogramma spp. Therefore, investigations were carried out in the biocontrol laboratory at North Carolina State University, Raleigh, USA, to examine costs (negative fitness effect as well as beneficial effects) for heat resistance acclimation in an egg parasitoid, T. exiguum by exposing of immature stages to 40 o C for different periods. The focus of the study was on acclimation across life-cycle stages rather than short term hardening of adults. Three questions ware considered. Firstly, can adult resistance to a high temperature shock, be increased by pre-pupal acclimation and / or by pupal acclimation in T. exiguum?. Secondly, are there other benefits of acclimation?. Thirdly are treatments that increase resistance associated with costs in terms of decreased parasitism or decreased longevity and can these costs be overcome by modifying acclimation treatments. So for, there has been little work in Trichogramma spp even through these parasitoids form an important component of IPM strategy in many countries and despite the fact that high temperature decrease Trichogramma spp., parasitism rate. The findings indicates that acclimation can occur without costs in T. exiguum and suggest a general phenotypic approach for separating acclimation costs from other fitness costs by sub -lethal exposures
Ethnographic perspectives on global mental health
The field of Global Mental Health (GMH) aims to influence mental health policy and practice worldwide, with a focus on human rights and access to care. There have been important achievements, but GMH has also been the focus of scholarly controversies arising from political, cultural and pragmatic critiques. These debates have become increasingly polarized, giving rise to a need for more dialogue and experience-near research to inform theorizing. Ethnography has much to offer in this respect. This paper frames and introduces five articles in the issue of Transcultural Psychiatry that illustrate the role of ethnographic methods in understanding the effects and implications of the field of global mental health on mental health policy and practice. The papers include ethnographies from South Africa, India and Tonga, that show the potential for ethnographic evidence to inform GMH projects. These studies provide nuanced conceptualizations of GMH’s varied manifestations across different settings, the diverse ways that GMH’s achievements can be evaluated, and the connections that can be drawn between locally observed experiences and wider historical, political and social phenomena. Ethnography can provide a basis for constructive dialogue between those engaged in developing and implementing GMH interventions and those critical of some of its approaches
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