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61.
This study assesses the impact of farmer field schools (FFS) on the productivity of vegetable farming in vegetable‐producing areas of East Java and Bali, Indonesia. The FFS have equipped over 3,000 vegetable farmers with integrated crop management knowledge applicable to chilies and tomatoes. The FFS are expected to enhance farmers’ capacity such that they can increase production. This study employs a difference‐in‐differences (DiD) method to overcome selection bias. A survey of 250 FFS‐graduated farmers and 250 non‐FFS farmers were purposively randomly selected from the overall community of farmers. Focus group discussion was used to support the survey. The results indicate that FFS were successful for enhancing farmers’ capability in vegetable farming. Farmers who participated in FFS have higher productivity than those who did not. Farmers also could adapt and adopt the knowledge gained from FFS as they underwent a process of learning by doing. The impacts of the increase in farmers’ capacity can be more evident if weaknesses during the FFS preparation and implementation can be overcome, to ensure more participation, flexibility to fit different conditions/needs and continuous learning.  相似文献   
62.
This case study is about a small group of workmen caught in a common dilemma regarding work safety. They must work safely and maintain production within a pathological organization that does not meaningfully reward participation or communication. They do so as a group and socially construct danger, injury and safety for themselves. They constitute a functioning counterculture and challenge the safety climate contrived by managers. Although limited in scope, the study suggests that we can learn from the details of their interactions with their work environment, with one another, and with their managers.  相似文献   
63.
This study applied theory from the employee learning and development literature to examine factors related to employees' perceptions of being job content plateaued and hierarchically plateaued. Results indicated that both types of plateauing were related to support from top management, career planning, job involvement, and education level. Furthermore, career exploration, motivation to learn, organizational tenure, and job tenure were related to perceptions of hierarchical plateauing, while supervisor support was related to job content plateauing. Additionally, the two types of plateauing differed in the relative strength of their relationship with the variables studied. Implications and future research suggestions are provided. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   
64.
Measuring progress toward international biodiversity targets requires robust information on the conservation status of species, which the International Union for Conservation of Nature (IUCN) Red List of Threatened Species provides. However, data and capacity are lacking for most hyperdiverse groups, such as invertebrates, plants, and fungi, particularly in megadiverse or high-endemism regions. Conservation policies and biodiversity strategies aimed at halting biodiversity loss by 2020 need to be adapted to tackle these information shortfalls after 2020. We devised an 8-point strategy to close existing data gaps by reviving explorative field research on the distribution, abundance, and ecology of species; linking taxonomic research more closely with conservation; improving global biodiversity databases by making the submission of spatially explicit data mandatory for scientific publications; developing a global spatial database on threats to biodiversity to facilitate IUCN Red List assessments; automating preassessments by integrating distribution data and spatial threat data; building capacity in taxonomy, ecology, and biodiversity monitoring in countries with high species richness or endemism; creating species monitoring programs for lesser-known taxa; and developing sufficient funding mechanisms to reduce reliance on voluntary efforts. Implementing these strategies in the post-2020 biodiversity framework will help to overcome the lack of capacity and data regarding the conservation status of biodiversity. This will require a collaborative effort among scientists, policy makers, and conservation practitioners.  相似文献   
65.
Assisted migration (AM) is the translocation of species beyond their historical range to locations that are expected to be more suitable under future climate change. However, a relocated population may fail to establish in its donor community if there is high uncertainty in decision-making, climate, and interactions with the recipient ecological community. To quantify the benefit to persistence and risk of establishment failure of AM under different management scenarios (e.g., choosing target species, proportion of population to relocate, and optimal location to relocate), we built a stochastic metacommunity model to simulate several species reproducing, dispersing, and competing on a temperature gradient as temperature increases over time. Without AM, the species were vulnerable to climate change when they had low population sizes, short dispersal, and strong poleward competition. When relocating species that exemplified these traits, AM increased the long-term persistence of the species most when relocating a fraction of the donor population, even if the remaining population was very small or rapidly declining. This suggests that leaving behind a fraction of the population could be a robust approach, allowing managers to repeat AM in case they move the species to the wrong place and at the wrong time, especially when it is difficult to identify a species’ optimal climate. We found that AM most benefitted species with low dispersal ability and least benefited species with narrow thermal tolerances, for which AM increased extinction risk on average. Although relocation did not affect the persistence of nontarget species in our simple competitive model, researchers will need to consider a more complete set of community interactions to comprehensively understand invasion potential.  相似文献   
66.
67.
We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity (RH) were simulated well (mean biases are–0.2K and 2.7%, respectively), but wind speeds were overestimated (mean bias is 0.5 m?s–1). At the Beijing station, sulfur dioxide (SO2) concentrations were overpredicted and sulfate concentrations were largely underpredicted, which may result from uncertainties in SO2 emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO2 emissions and incorporating heterogeneous oxidation of dissolved SO2 by nitrogen dioxide (NO2) on sulfate formation during winter haze. The results suggest that doubling SO2 emissions do not significantly affect sulfate concentrations, but adding heterogeneous oxidation of dissolved SO2 by NO2 substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO2 to sulfate conversion in the HetS (heterogeneous oxidation by NO2) case reduces SO2 concentrations, it is still largely overestimated by the model, indicating the overestimations of SO2 concentrations in the North China Plain (NCP) are mostly due to errors in SO2 emission inventory.
  相似文献   
68.
Incorporating the missing heterogeneous oxidation of S(IV) by NO2 into the WRF-Chem model. Sulfate production is not sensitive to increase in SO2 emission. The newly added reaction reproduces sulfate concentrations well during winter haze. We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity (RH) were simulated well (mean biases are -0.2K and 2.7%, respectively), but wind speeds were overestimated (mean bias is 0.5 m?s−1). At the Beijing station, sulfur dioxide (SO2) concentrations were overpredicted and sulfate concentrations were largely underpredicted, which may result from uncertainties in SO2 emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO2 emissions and incorporating heterogeneous oxidation of dissolved SO2 by nitrogen dioxide (NO2) on sulfate formation during winter haze. The results suggest that doubling SO2 emissions do not significantly affect sulfate concentrations, but adding heterogeneous oxidation of dissolved SO2 by NO2 substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO2 to sulfate conversion in the HetS (heterogeneous oxidation by NO2) case reduces SO2 concentrations, it is still largely overestimated by the model, indicating the overestimations of SO2 concentrations in the North China Plain (NCP) are mostly due to errors in SO2 emission inventory.  相似文献   
69.
Long-spined sea urchins (Diadema antillarum-a) began dying in January 1983 and over the next year virtually disappeared from the Caribbean. Decades later, Diadema densities remain low, with only very limited recovery in some areas. Ecological extinction of Diadema is a factor in the transformation of coral to barren algae-covered rock that has occurred in the Caribbean during the past 25 years. Working with sea urchins collected from St. Croix, United States Virgin Islands, we asked whether the immune system of Diadema differs from those of other common Caribbean urchins that did not experience the die-off. Using isolated coelomocytes, we tested humoral responses of the urchins with classic stimulators in numerous humoral immune assays. All coelomocytes responded to stimulators—with one notable and statistically significant exception—D. antillarum did not respond to lipopolysaccharide. Our results indicate that Diadema may have a weakness in its humoral defense response that is independent of local stressors and may help explain why Caribbean Diadema was vulnerable to the 1983 epidemic and has shown slow and limited recovery since then.  相似文献   
70.
Free-ranging cervids acquire most of their essential minerals through forage consumption, though occasionally seek other sources to account for seasonal mineral deficiencies. Mineral sources occur as natural geological deposits (i.e., licks) or as anthropogenic mineral supplements. In both scenarios, these sources commonly serve as focal sites for visitation. We monitored 11 licks in Rocky Mountain National Park, north-central Colorado, using trail cameras to quantify daily visitation indices (DVI) and soil consumption indices (SCI) for Rocky Mountain elk (Cervus elaphus) and mule deer (Odocoileus hemionus) during summer 2006 and documented elk, mule deer, and moose (Alces alces) visiting licks. Additionally, soil samples were collected, and mineral concentrations were compared to discern levels that explain rates of visitation. Relationships between response variables; DVI and SCI, and explanatory variables; elevation class, moisture class, period of study, and concentrations of minerals were examined. We found that DVI and SCI were greatest at two wet, low-elevation licks exhibiting relatively high concentrations of manganese and sodium. Because cervids are known to seek Na from soils, we suggest our observed association of Mn with DVI and SCI was a likely consequence of deer and elk seeking supplemental dietary Na. Additionally, highly utilized licks such as these provide an area of concentrated cervid occupation and interaction, thus increasing risk for environmental transmission of infectious pathogens such as chronic wasting disease, which has been shown to be shed in the saliva, urine, and feces of infected cervids.  相似文献   
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