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To assess whether and how environmental values and sense of place relate to sustainable farming practices, we conducted a study in South Kona, Hawaii, addressing environmental values, sense of place, and farm sustainability in five categories: environmental health, community engagement and food security, culture and history, education and research, and economics. We found that the sense of place and environmental values indexes showed significant correlation to each category of sustainability in both independent linear regressions and multivariate regression. In total, sense of place explained a larger share of the overall farm performance. However, each indicator showed relative strengths; environmental values showed significantly higher correlation to environmental and educational practices. Furthermore the scales were complimentary, and the use of both scales greatly improved prediction of good farming practices from a multiple-impact perspective. With implications for community and environmental impacts, results suggest that a more comprehensive view of farmers’ environmental values and place connections may help illuminate individual farmers’ decisions and sustainability-related practices.  相似文献   
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This study investigated the acute toxicity (LC50-24 hr) effects of the essential oil of Cymbopogon citratus for adult Argulus sp. and Dolops discoidalis, before and during oviposition. In vitro acute toxicity (LC50-24 hr) was tested using 20, 40, 60, 80, 100, 120, 140 and 160 μg/L of C. citratus essential oil, and two control groups (one with cultivation tank water and one with cultivation tank water + alcohol) were used. Specimens of Argulus sp. and D. discoidalis submitted to acute toxicity were evaluated using histological procedures. The major chemical compounds of C. citratus essential oil were geranial (47.5%), neral (35.6%) and myrcene (6.7%). The LC50-24 hr for Argulus sp. adults was 67.97 μg/L, while for D. discoidalis it was 59.55 µg/L. In the oviposition of both species of argulids, maximum mortality began with treatments of 140 μg/L, while the LC50-24 hr for Argulus sp. and D. discoidalis was 83.98 μg/L and 82.48 μg/L, respectively. In both argulid species exposed to C. citratus essential oil, morphological alterations were observed only in the eyes, and they occurred in the ommatidium and rhabdomeres and were dependent on the concentration of C. citratus essential oil and the parasite species.  相似文献   
4.
Abstract

Potato cyst-nematode species are believed to have evolved in South America but now have a worldwide distribution and can be major and persistent pests except in the warmest soils. Both species contain pathotypes and their correct identification, although difficult, is important when planning control with resistant potatoes. Some closely related and very similar species are of minor economic importance. Resistant cultivars available at present are effective against only some pathotypes and except where high crop values make use of nematicides economic, it is important to combine extended crop rotation with such cultivars.  相似文献   
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Florida is the largest producer of fresh-market tomatoes in the United States. Production areas are typically intensively managed with high inputs of fertilizer and irrigation. The objectives of this 3-year field study were to evaluate the interaction between N-fertilizer rates and irrigation scheduling on yield, irrigation water use efficiency (iWUE) and root distribution of tomato cultivated in a plastic mulched/drip irrigated production systems. Experimental treatments included three irrigation scheduling regimes and three N-rates (176, 220 and 230 kg ha−1). Irrigation treatments included were: (1) SUR (surface drip irrigation) both irrigation and fertigation line placed right underneath the plastic mulch; (2) SDI (subsurface drip irrigation) where the irrigation line was placed 0.15 m below the fertigation line which was located on top of the bed; and (3) TIME (conventional control) with irrigation and fertigation lines placed as in SUR and irrigation being applied once a day. Except for the “TIME” treatment all irrigation treatments were controlled by soil moisture sensor (SMS)-based irrigation set at 10% volumetric water content which was allotted five irrigation windows daily and bypassed events if the soil water content exceeded the established threshold. Average marketable fruit yields were 28, 56 and 79 Mg ha−1 for years 1-3, respectively. The SUR treatment required 15-51% less irrigation water when compared to TIME treatments, while the reductions in irrigation water use for SDI were 7-29%. Tomato yield was 11-80% higher for the SUR and SDI treatments than TIME where as N-rate did not affect yield. Root concentration was greatest in the vicinity of the irrigation and fertigation drip lines for all irrigation treatments. At the beginning of reproductive phase about 70-75% of the total root length density (RLD) was concentrated in the 0-15 cm soil layer while 15-20% of the roots were found in the 15-30 cm layer. Corresponding RLD distribution values during the reproductive phase were 68% and 22%, respectively. Root distribution in the soil profile thus appears to be mainly driven by development stage, soil moisture and nutrient availability. It is concluded that use of SDI and SMS-based systems consistently increased tomato yields while greatly improving irrigation water use efficiency and thereby reduced both irrigation water use and potential N leaching.  相似文献   
7.
Long-term culture of bone marrow derived stromal colony forming cells (S-CFC) in matrix and nutrient defined agar medium resulted in stromal cell colonies that pass sequentially through three distinct morphological stages: firstly, aggregated loose syncytium of round to ovoid cells (stage I), a second developmental stage of large branching colonies in which the cells become enlarged, elongated with cytoplasmic projections forming a loosely anastomized network with adjacent cells (stage II), and finally cells become dissociated, loosing their long, thin cytoplasmic filaments and breaking their contacts with one another, but remain large and retain a bi-polar nature (stage III). Cells were also grown in liquid medium in a culture microenvironment closely resembling conditions of haemopoiesis in vitro. Using a panel of well defined monoclonal antibodies reactive against the rat, rabbit and human growth hormone receptors, this study found immunochemical evidence of the presence and localization of binding sites of growth hormone (GH) in the cell membrane and extra-nuclear Golgi area of long-term bone marrow derived human stromal cells in liquid and semi-solid nutrient agar mediums. GH-receptor immunoreactivity was present in small proliferating progenitor cells, myofibroblast-like cells, large reticular fibroblast cells, adipocytes and endothelial cells. Only MAb known to be reactive against human tissue resulted in strong immunoreactivity. The expression of GH-receptors not only on small proliferating, but also on the well differentiated cells, indicates a role for growth hormone on non-progenitor cells. GH-receptor immunoreactivity on differentiating and/or differentiated cells suggests that GH is also necessary for, or has a trophic function in differentiation. We propose that direct GH action is necessary not only for differentiation of progenitor cells as implied by the dual effector hypothesis, but also their subsequent clonal expansion, differentiation and maintenance.  相似文献   
8.
We can no longer afford to ignore the serious potential consequences of our lavish use of energy. Continuation of the present rate of increase, particularly with the trend to imported fuels, will lead in short order to a level of dependency on imports which is disturbing for both the national security and the balance of payments. The inevitable rise in the price of energy will presumably lead to some increases in the domestic energy supply. But our reserves, particularly in the preferred forms of petroleum, gas, and even low-sulfur coal, are finite. Thus, the energy problem must also be attacked from the standpoint of energy conservation. The forthcoming rise in fuel prices will, of course, make more attractive some forms of conservation which at present are economically marginal. Nevertheless, consumers, industry, and government will have to make difficult choices in the years ahead: between greater convenience and lower energy bills, between the high capital costs of energy conservation measures and the long-term dollar savings from increased energy efficiency, and between environmental protection and the availability of needed energy supplies. Existing capabilities and technology, on which short- and midterm improvements must be based, appear to offer substantial possibilities for reducing U.S. energy consumption within the next decade (11). Long-term solutions to the energy problem, however, will depend to a considerable extent on the continuing appearance of new technological capabilities for increased efficiency of energy utilization and increased integration of energy applications. The capacity for continuing technological advances is, of course, dependent in turn on a strong relevant scientific base. A word of caution is necessary. Recent experience has shown that technological advances alone will not solve the problem. The problem spans not only the traditional physical and engineering sciences but also those sciences which deal with human attitudes and actions, that is, the social sciences, and includes a more fundamental understanding of underlying economic principles. The challenge to all sectors of American science should be clear.  相似文献   
9.
Sentinel steers were placed with 3 beef herds on irrigated pastures in southern Idaho for 1-month periods from May until November 1982 to determine the transmission pattern of Fasciola hepatica. Transmission was found to increase through the pasture season, reaching a peak during November. Overwintering of metacercariae or snail-borne stages was not found to contribute to infections in the year under study. A variety of species of Lymnaea were found to be available in southern Idaho as potential intermediate hosts. The enzyme-linked immunosorbent assay was found to be a good serologic indicator of light infections with F hepatica. The serum gamma-glutamyltransferase activity was not diagnostically significant when the degree of fluke infection was low.  相似文献   
10.
The prevalance of Anaplasma marginale-infected cows, as determined by use of the modified rapid card agglutination (MRCA) test, was measured during a 4-year period (1980-1983). The prevalence of A marginale-infected cows, defined as positive reactors on the MRCA test, remained constant (31%-37%). The apparent incidence of A marginale transmission to susceptible cows was approximately 7% from 1980 to 1981, 8% from 1981 to 1982, and no transmission from 1982 to 1983. The occasional MRCA-positive cow became negative on the MRCA test, and 1 cow was determined to be free of A marginale infection by subinoculation of 100 ml of the cow's blood into a susceptible, splenectomized calf. Dermacentor andersoni, a known vector of A marginale, was often found on the cattle and in their environment. However, A marginale was not transmitted to susceptible, splenectomized calves, using collected ticks. Of 56 calves born to MRCA-positive cows, 82% were MRCA-positive within the first 3 months of life. These calves converted to MRCA-negative status and were determined to be free of A marginale infection by subinoculation of their blood into susceptible, splenectomized calves, indicating the passive transfer of colostral antibodies.  相似文献   
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