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991.
992.
This paper focuses on examining the dynamic nature of community supported agriculture (CSA) and the real-world experiences which mark its contours, often making it distinct from the early idealized CSA “model.” Specifically, our study examines the narratives of the farmers of Devon Acres CSA over its duration, in tandem with a survey of recent shareholders in order to understand and explain its evolution. The framework we develop here shows that this CSA is largely characterized by instrumental and functional beliefs and practices, with some elements in the collaborative mode. A key contribution of this research is the development of a framework which helps to highlight the relative fluidity and patchwork quality of CSA participant positions over time. At Devon Acres, the real-world factors and issues influencing CSA evolution are seen to be products of both the local and larger contexts, evident in such areas as shifts in farmer learning and adaptation, differences between beliefs and practices in member volunteer efforts, and changes in farm and resource conditions. With respect to CSA more broadly, we argue that the reality of dominant food system context and site-specific influences on CSA development compels us to rework our attachment to early idealized “model” traits. Expansion in CSA numbers, evidence of adaptation and situated learning, and retention of the local and organic as core traits, speak to the pragmatic yet transformative potential of CSA contribution to food system change.
Robert FeaganEmail:

Robert Feagan   PhD, is a faculty member in the interdisciplinary Contemporary Studies Program at the Brantford Campus of Wilfrid Laurier University in Ontario, Canada. His research and teaching interests are in local and regional food systems—farmers’ markets, CSAs, etc., in university–community partnerships, in community development, and in the green-burial movement. Ideas and objectives of “sustainability” underlie his many research directions. Amanda Henderson   earned a Masters Degree from the Faculty of Environmental Studies at York University in Toronto. She lives and works on a communal eco-farm in rural Ontario, Canada.  相似文献   
993.
A study to estimate the seroprevalence of Contagious Caprine Pluropneumonia (CCPP) in southern Ethiopia was conducted from November 2005 to June 2006. Two districts from sedentary (Arbaminch and Boreda) and pastoral (Hammar and Bena-Tsemay) production systems were included in the study. Sera samples were collected from 913 goats (234 from sedentary and 679 from pastoral) to check for CCPP serostatus. The animals were sampled from 155 flocks (44 pastoral and 111 sedentary). Five clinically suspected CCPP cases were also sacrificed and attempt was made to isolate Mycoplasma capricolum capripneumoniae (MccP) from lung tissue, nasal swab and plural exudates. Sera samples were tested for the presence of CCPP antibodies using CFT. The overall seroprevalence recorded in the study was 18.61%. The corresponding seroprevalences for sedentary and pastoral production systems were 27.78% and 15.46% respectively. Regarding districts, the prevalence in Hammar was 15.63% while that of Bena-Tsemay 15.29%. In Arbaminch and Boreda the percent of seroreactors were 23.01 and 32.23% respectively. Out of 44 pastoral and 111 sedentary flocks, 50.45% of pastoral and 65.91% of sedentary flocks had at least one seroreactor goat per flock respectively. Both in the univariable and multivariable logistic regression analysis, seropositivity was found to have strong association with sedentary production system (P < 0.05, OR = 2.24) and adult age (P < 0.05, OR = 1.77). In microbiological study, two broth cultures from thoracic fluid and two broth cultures from lung tissue samples were found to be positive for Mycoplasma capricolum capripneumoniae (MccP). In conclusion, both the serological study and bacteriological isolation confirmed the disease CCPP being an important disease that demands serious attention in both production systems.  相似文献   
994.

Context

Policy decisions form a major driver of land use change, with important implications for socially and environmentally susceptible regions. It is well known that there can be major unintended consequences, especially where policies are not tailored to regionally specific contexts.

Objectives

In this paper we assess the implications of 60 years of agricultural policies on soil erosion prevention (SEP) by vegetation, an essential regulating ecosystem service in Mediterranean Europe.

Methods

To assess these implications we produced and analysed a time series of land cover/use and environmental conditions datasets (from 1951 to 2012) in relation to changing agricultural policies for a specific region in the southern Portugal. A set of indicators related to SEP allowed us to identify that land use intensification as increased soil erosion in the last 60 years.

Results

Particularly in the last 35 years, as a consequence of headage payments for cattle, the agricultural policy had a significant effect in the density and renewal of the tree cover, resulting in drastic effects for the provision of the SEP service. These are more significant after 1986, coinciding with the implementation of several Common Agricultural Policy instruments focused on increasing the modernization and productivity capacity of farm systems.

Conclusions

The results show some unintended effects of agricultural policy mechanisms on ecosystem service provision and highlight the need for context-based policies, tailored to the environmental constrains and potentials of each region.
  相似文献   
995.
In Central Europe vast wetland areas have been converted into agricultural land over the past few centuries. Long-term spatially explicit reconstructions of wetland cover changes at regional scale are rare but such information is vital for setting appropriate wetland conservation and restoration goals. In this study wetland cover change over the past 150 years was analyzed for the Canton Zurich (Switzerland) using information from historical and current topographical maps. Mapping instructions changed significantly over time, i.e., wetlands were mapped more conservatively on older maps. Therefore a technique was developed to account for changes in mapping instructions and to reconstruct a series of comparable maps spanning 1850–2000. Wetland cover dramatically decreased from 13,759 ha in 1850 (more than 8% of the total study area) to 1,233 ha in 2000 (less than 1%). Largest loss is observed for the first half of the twentieth century when more than 50% of the total wetland loss occurred. In 1850, almost all wetland patches were connected in two large networks defined by a 500 m buffer around all wetland patches to account for typical dispersal distances of wetland animals. Despite extensive wetland loss, this networks remained largely intact until 1950, but then collapsed into many medium and small networks consisting of only few wetland patches. In addition to the direct loss of wetland habitats increased habitat fragmentation is limiting metapopulation dynamics and hindering genetic exchange between populations. Amphibians and other wetland animals are particularly prone to habitat fragmentation because of their limited migration abilities. This may lead to time-delayed extinction in the future because current species occurrence might rather reflect historical than current wetland cover and habitat configuration. Future restoration efforts should focus on reestablishing connectivity between remaining smaller wetland networks.  相似文献   
996.
Citrus hongheensis is a critically endangered species endemic to the Honghe river region in southeastern Yunnan, China. Its genetic diversity and differentiation were investigated using Inter-Simple Sequence Repeat (ISSR) markers. One hundred primers were screened, and a total of 245 loci were amplified from seven natural populations by 13 informative and reliable primers. Of these 245 ISSR loci, 233 were polymorphic and the detected variations revealed a relatively high level of intraspecific genetic diversity. At the population level, the mean percentage of polymorphic loci (PPB) was 36.50%, while the average expected heterozygosity (He) and Shannon diversity index (Ho) were 0.1327 and 0.1972, respectively. At the species level (across all populations), PPB was 95.10%, while He and Ho were 0.3520 and 0.5195, respectively. A high Gst value (0.6247) indicated that there is significant differentiation among populations, which was confirmed by AMOVA analysis (Φst = 0.6420). Pairwise genetic identity (I) values among populations ranged from 0.6341 to 0.7675, with a mean of 0.7008. We propose that the high level of genetic differentiation may be the result of habitat fragmentation and limited gene flow (Nm = 0.1502). For effective in situ conservation and population restoration of C. hongheensis it will be important to maintain historical processes, including high outbreeding rates, sufficient gene flow, and large effective population sizes.  相似文献   
997.
This study was performed to obtain information on the occurrence of multiple paternities in three species of viviparous Japanese surfperch using allelic markers of microsatellite DNA loci. Direct evidence for multiple fertilizations was established by reconstructing paternal genotypes from the progeny of gravid females. Multiple paternities were ascertained in five of 10 broods of Ditrema temmincki and in three of nine broods of Neoditrema ransonneti, but not in Ditrema viride. The number of patrilines detected in the progeny of D. temmincki and N. ransonneti females were two or three, respectively, as determined by the GERUD v2.0 algorithm for reconstructing parental genotypes from half-sib progeny arrays.  相似文献   
998.
A carbonaceous sorbent was prepared from the wood of Japanese larch (Larix leptolepis) by dehydration with concentrated sulfuric acid in a 69% yield. The abilities of the sorbent to remove Cr(VI) from aqueous solutions were investigated. Research parameters included the initial solution pH, temperature, and initial concentration of Cr(VI) in solution. The removal of Cr(VI) was highly solution pH dependent and was mainly governed by physicochemical sorption under weak acidic conditions. The equilibrium data fit well in the Langmuir isotherm model. The Langmuir constants were calculated at different temperatures, and the sorption capacity increased with rising temperature, indicating the endothermic nature of the Cr(VI) sorption onto the sorbent. The desorption experiments suggest that the Cr(VI) sorption is generally irreversible, owing to strong interaction of HCrO 4 with the active sites of the sorbent.  相似文献   
999.

•Introduction  

In the context of climate change, assessing climate–growth relationships is of high importance in order to understand how forest ecosystems evolve and to test climate models at regional scale.  相似文献   
1000.
The effect of Chenopodium quinoa seeds on lipid profile, glucose level, protein metabolism and selected essential elements (Na, K, Ca, Mg) level was determined in high—fructose fed male Wistar rats. Fructose decreased significantly LDL [42%, p < 0.01] and activity of alkaline phosphatase [20%, p < 0.05], and increased triglycerides level [86%, p < 0.01]. The analysis of blood of rats fed quinoa indicated, that these seeds effectively reduced serum total cholesterol [26%, p < 0.05], LDL [57%, p < 0.008] and triglycerides [11%, p < 0.05] when compared to the control group. Quinoa seeds also significantly reduced the level of glucose [10%, p < 0.01] and plasma total protein level [16%, p < 0.001]. Fructose significantly decreased HDL [15%, p < 0.05] level in control group but when the quinoa seeds were added into the diet the decrease of HDL level was inhibited. Quinoa seeds did not prevent any adverse effect of increasing triglyceride level caused by fructose. It was shown in this study that quinoa seeds can reduce most of the adverse effects exerted by fructose on lipid profile and glucose level.  相似文献   
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