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41.
Against the backdrop of viewing marketing intermediaries in developing countries as parasites, this study examined the validity of such a view, especially in the context of mandarin (a species of orange) marketing in a mountain district of Nepal. Necessary information was collected from all major stakeholders such as farmers, collectors and commission agents, and the relative position of farmers in terms of their gains was analyzed by employing three criteria: price of mandarin, marketing margin and income distribution. Income distribution among marketing functionaries “with” and “without” transaction cost has been analyzed. Similarly, marketing margin and farmers’ share of gross income are also analyzed ‘with’ and ‘without’ the cost of malicious practices by marketing intermediaries. Findings of the study revealed that farmers in the study area are receiving a fair share of the benefit accruing from the marketing of mandarin. However, taking advantage of their weak bargaining power and poor economic condition, marketing intermediaries are harassing and cheating them in different ways. Policy recommendations are made to institutionalize and strengthen the group-marketing system to address such inherent problems.  相似文献   
42.
Tree mortality is an important component of forest tree and stand growth models, which provide decision support for forest managers. Mortality patterns, however, are highly variable and difficult to describe. Despite numerous investigations aimed at developing tree survival models, there are still important gaps that need to be filled. This paper used a large-scale repeated measure dataset collected from permanent sample plots established in 1980/81 across the natural range of loblolly pine (Pinus taeda L.) in the Piedmont, Atlantic Coastal Plain and Gulf Coastal Plain physiographic regions of the US. The primary objective of this study was to explain the survival of loblolly pine trees using time-varying covariates such as diameter at breast height, total tree height, crown ratio, stand age, stand basal area, and dominant height. In this paper, individual-tree mortality was described using a semiparametric proportional hazards regression model. Shared frailty models were used to account for unobserved heterogeneity not explained by the observed covariates. Our investigation involved developing a modeling comparison procedure, predicting mortality based on a frailty model, and quantifying the predictive ability for tree mortality. The survival model developed using a large scale database provides further understanding of mortality trends in planted stands of loblolly pine. The survival model will enable forest managers to more accurately specify initial planting density, thinning schedules, and other management interventions.  相似文献   
43.
During 1988 thousands of harbor seals (Phoca vitulina) died in European seas as a result of morbillivirus infection. Six harbor porpoises (Phocoena phocoena) found stranded on the coast of Northern Ireland in late 1988 were submitted to our laboratory for necropsy. Pneumonia was the main necropsy finding in three of these animals. Microscopic lung lesions characterized by necrosis of bronchial and bronchiolar epithelium and infiltration of alveoli with leukocytes, lymphoid cells, macrophages, and multinucleate syncytia were seen in all six porpoises. Cytoplasmic and nuclear acidophilic inclusions characteristic of morbillivirus infection were common in bronchial and bronchiolar epithelial cells and in alveolar macrophages and syncytia. Brain alterations included degeneration and necrosis of neurons, microglial infiltration, and perivascular cuffing. There were cytoplasmic and nuclear acidophilic inclusions in many neurons. Immunoperoxidase staining of morbillivirus antigen was seen in many tissues including lung, brain, spleen, and urinary bladder. Alterations in our porpoises were similar to those seen in distemper in seals and many species of terrestrial mammals. Systemic viral disease has not previously been documented in Cetacea.  相似文献   
44.
  1. All five species of sawfishes (family Pristidae) are amongst the most threatened marine fishes in the world, with steep population declines and local extinctions documented across their ranges.
  2. Sawfishes have featured in Sri Lankan species checklists since 1889. However, landing records are extremely rare and little information is available on their status, diversity, and recent occurrences.
  3. Interviews were conducted with 300 fishers and 10 fish traders. Only 39% of fishers (n = 118) could identify sawfishes, 37% had seen sawfishes (although half not since 1992), and only 10.7% had ever caught one. No respondents under 30 years could identify sawfishes. Older respondents (>50 years) were more likely to have caught sawfishes and reported seeing them frequently until 30 years ago, while younger respondents had only seen them at landing sites and, at most, once or twice in their life. Only 10 respondents had seen a sawfish in the last decade, suggesting that sawfishes were relatively abundant in the past but that populations have drastically declined.
  4. Of the 32 respondents who had caught sawfishes, 30 reported declining numbers and attributed it to fishing pressure. These steep declines coincide with the time of increased fishing effort, the development of the aquaculture industry, and resulting degradation of coastal habitats in the 1980–1990s.
  5. Overall, sawfishes had little cultural significance although fishers had specific names for the different species occurring here and rostra were sometimes donated to Catholic churches for ‘good luck’. Landed sawfishes were primarily sold for meat and traders appeared unaware of the high value of fins.
  6. It is likely that sawfishes are now functionally extinct as a component of coastal ecosystems in Sri Lanka. Immediate action including species-specific legislation and critical habitat protection is urgently needed to provide remaining sawfishes and other sharks and rays with a fighting chance.
  相似文献   
45.
  1. The process of understanding the rapid global decline of sawfishes (Pristidae) has revealed great concern for their relatives, the wedgefishes (Rhinidae) and giant guitarfishes (Glaucostegidae), not least because all three families are targeted for their high‐value and internationally traded ‘white’ fins.
  2. The objective of this study was to assess the extinction risk of all 10 wedgefishes and six giant guitarfishes by applying the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, and to summarize the latest understanding of their biogeography and habitat, life history, exploitation, use and trade, and population status. Three of the 10 wedgefish species had not been assessed previously for the IUCN Red List.
  3. Wedgefishes and giant guitarfishes have overtaken sawfishes as the most imperilled marine fish families globally, with all but one of the 16 species facing an extremely high risk of extinction through a combination of traits: limited biological productivity; presence in shallow waters overlapping with some of the most intense and increasing coastal fisheries in the world; and overexploitation in target and by‐catch fisheries, driven by the need for animal protein and food security in coastal communities and the trade in meat and high‐value fins.
  4. Two species with very restricted ranges, the clown wedgefish (Rhynchobatus cooki) of the Malay Archipelago and the false shark ray (Rhynchorhina mauritaniensis) of Mauritania, may be very close to extinction.
  5. Only the eyebrow wedgefish (Rhynchobatus palpebratus) is not assessed as Critically Endangered, with it occurring primarily in Australia where fishing pressure is low and some management measures are in place. Australia represents a ‘lifeboat’ for the three wedgefish and one giant guitarfish species occurring there.
  6. To conserve populations and permit recovery, a suite of measures will be required that will need to include species protection, spatial management, by‐catch mitigation, and harvest and international trade management, all of which will be dependent on effective enforcement.
  相似文献   
46.
Climate change is likely to affect the persistence of large, space-requiring species through habitat shifts, loss, and fragmentation. Anthropogenic land and resource use changes related to climate change can also impact the survival of wildlife. Thus, climate change has to be integrated into biodiversity conservation plans. We developed a hybrid approach to climate-adaptive conservation landscape planning for snow leopards in the Himalayan Mountains. We first mapped current snow leopard habitat using a mechanistic approach that incorporated field-based data, and then combined it with a climate impact model using a correlative approach. For the latter, we used statistical methods to test hypotheses about climatic drivers of treeline in the Himalaya and its potential response to climate change under three IPCC greenhouse gas emissions scenarios. We then assessed how change in treeline might affect the distribution of snow leopard habitat. Results indicate that about 30% of snow leopard habitat in the Himalaya may be lost due to a shifting treeline and consequent shrinking of the alpine zone, mostly along the southern edge of the range and in river valleys. But, a considerable amount of snow leopard habitat and linkages are likely to remain resilient to climate change, and these should be secured. This is because, as the area of snow leopard habitat fragments and shrinks, threats such as livestock grazing, retaliatory killing, and medicinal plant collection can intensify. We propose this approach for landscape conservation planning for other species with extensive spatial requirements that can also be umbrella species for overall biodiversity.  相似文献   
47.
48.

Background

Expression of economically relevant proteins in alternative expression platforms, especially plant expression platforms, has gained significant interest in recent years. A special interest in working with plants as bioreactors for the production of pharmaceutical proteins is related to low production costs, product safety and quality. Among the different properties that plants can also offer for the production of recombinant proteins, protein glycosylation is crucial since it may have an impact on pharmaceutical functionality and/or stability.

Results

The pharmaceutical glycoprotein human Granulocyte-Colony Stimulating Factor was transiently expressed in Nicotiana benthamiana plants and subjected to mammalian-specific mucin-type O-glycosylation by co-expressing the pharmaceutical protein together with the glycosylation machinery responsible for such post-translational modification.

Conclusions

The pharmaceutical glycoprotein human Granulocyte-Colony Stimulating Factor can be expressed in N. benthamiana plants via agroinfiltration with its native mammalian-specific mucin-type O-glycosylation.
  相似文献   
49.
尼泊尔是"一带一路"沿线国家中南亚地区的重要国家,也是我国重点援助的国家。尽管尼泊尔森林资源丰富,生物多样性高,但是近年来森林资源下降趋势明显。鉴于竹子在保护森林资源和发展农村经济中的地位日益显著,尼泊尔政府把推动竹藤等非木质林产品开发利用作为林业发展的重要内容和减贫的重要措施。文中对尼泊尔竹子资源培育、加工利用、发展政策及科研进展等进行了综述,提出了我国与尼泊尔开展竹业合作的领域和方式,可为深化中尼两国林业合作和提高我国对外援助水平提供重要的参考信息。  相似文献   
50.
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