首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Genotypic differentiation studies involving three native pasture grasses Danthonia linkii Kunth, D. richardsonii Cashmore and D. racemosa R.Br. were made, using populations both collected from the field and grown from selfed seed, to investigate the influence of the intensive grazing and high soil fertility associated with sheep camps on a number of morphological and developmental characters. Each species was represented by at least a pair of populations one of which was sampled from a sheep campsite, the other(s) from an adjacent site as close as possible to the camp but outside its influence. The sheep camp populations were generally more prostrate with shorter tillers, greater tiller numbers, later flowering time, and in one population group, a larger number of seeds set. These differences were more apparent in the parent populations collected from the field but grown under uniform conditions than in the F1 populations produced from selfed seed. These population differences were interpreted as representing genotypic differentiation produced by intensive selection pressures introduced since the development of the sheep camps. They were certainly more intensive in populations drawn from sheep camps which had been in existence for a longer time. The selection pressures which produced the new populations also appeared to maintain a broad base of genetic variability rather than result in populations more uniform than the original.  相似文献   

2.
3.
ABSTRACT

Designed to provide temporary shelter to the displaced, in protracted refugee situations camps become places of long-term residency and undergo processes of urban change. The complex realities of protracted encampment challenge the dichotomy between the city (as a norm) and the camp (as an exception) that underpins dominant theoretical models of refugee camps. Instead, the theoretical lens of urban margins allows us to circumvent this binary and analyse the camps from the perspective of their relation to the city and the state. Rather than a specific location, this article approaches urban marginality as a condition produced by unequal power relations behind the enforcement of a particular urban order. Based on two years of ethnographic fieldwork, it draws on the case of Palestinian refugee camps in the West Bank. Unlike the majority of studies on Palestinian camps that focus either on top-down politics of exclusion or political agency of camp residents, the article examines how different actors, interests and modes of exercising power (both formal and informal) intersect in camp space and produce, as well as resist and subvert, the condition of urban marginality.  相似文献   

4.
With the passing of time, it becomes increasingly unlikely that major studies of concentration camp survivors will appear. Nearly forty years have gone by since the camps were liberated. Most survivors have died, and their children are approaching middle age. This paper provides a brief summary of the available data. Beginning with an account of the events leading to the Holocaust, it goes on to summarize the major types of psychological defenses employed by the prisoners, and also describes the group or social activity in the camps. The long lasting psychological, psychiatric, and medical consequences of internment are then reviewed. The paper concludes with a discussion of studies of the children of survivors.  相似文献   

5.
M Tenenbein 《CMAJ》1997,156(9):1268-1269
This fall Ontario braced for possible strikes by public servants and teachers. A year earlier, the province''s physicians were preparing their own job action. Walkouts by physicians, which have not been uncommon since the introduction of medicare, create two camps. In one are physicians who say legal job actions are ethical and often improve health care for patients. In the other are some doctors and ethicists who question whether doctors have an ethical right to withdraw services, even if it is legal to do so. Nicole Baer interviewed members of both camps.  相似文献   

6.

Background

Introducing sustainability and self-reliance is essential in chronic humanitarian emergencies before financial assistance is phased out. In Pakistan-based Afghan refugee camps, this was attempted through shifting from indoor residual spraying (IRS) to the subsidized sale of insecticide-treated nets (ITNs) for prevention of malaria and anthroponotic cutaneous leishmaniasis (ACL). Here we outline the strategy and document the progress to provide guidance for replication of similar approaches in other chronic refugee situations.

Methods

The operational monitoring data presented were collected through: (i) two surveys of knowledge, attitude and practice (KAP); (ii) routine sales reporting of health-care providers; (iii) records completed during field visits; and (iv) registers used during annual re-treatment campaigns.

Results

From 2000 until 2003, subsidized ITN sales expanded from 17 to 44 camps. Based on 2003 sales records, maximum coverage from subsidized sales exceeded 50% in 13 camps and 20% in an additional 14 camps. Free annual treatment campaigns showed that many refugees were in possession of non-programme nets, which were either locally-made or had leaked from an ITN programme in Afghanistan. Estimated re-treatment coverage of sold and existing nets through annual campaigns exceeded 43% in all camps and was above 70% in the majority.

Conclusion

Subsidized sales of ITNs have effectively introduced the components of sustainability and self-reliance to the prevention of malaria and ACL in Afghan refugee camps. Similar approaches should be investigated in other chronic refugee situations to discourage expectations of continuing humanitarian donations that cannot be fulfilled.  相似文献   

7.
《L'Anthropologie》2021,125(4):102924
The subject of the research described in this article is a collection of flint artefacts obtained in the course of an exploration of one of the Mesolithic assemblages from site 29 in Paliwodzizna in Central Poland. The artefacts were subjected to a typological-technological analysis, a use-wear analysis and multi-faceted spatial analyses. As a result of the studies it was concluded that the collection might be affiliated with the Komornica culture and dated to the Atlantic period, which was confirmed by radiocarbon dating. The functional structure of the collection and the spatial organisation of the camp indicate that it was a hunting camp briefly used by a small group of people. The structure was compared with other camps of similar function from the region and the type of mobility of the hunter-gatherer groups that were using the site was considered.  相似文献   

8.
Although mitochondria are known to exhibit a wide variety of morphologies in different cells, the mechanism by which these shapes are established and regulated are largely unknown. Several potential shape-forming proteins have been recently identified. Some studies suggest that these proteins control shape by mediating attachment of mitochondria to the cytoskeleton, while other studies indicate that these proteins form part of a connection between the mitochondrial outer and inner membranes. Complicating matters, a recent study raises the possibility that one or more of these shape-forming proteins plays a direct role in the import and assembly of mitochondrial proteins synthesized in the cytosol.  相似文献   

9.
Asian elephants (Elephas maximus) in western zoos are likely to become extinct unless elephants are regrouped into breeding units or additional elephants are imported from range States. There have been proposals for the export of elephants from elephant camps in Sumatra, Indonesia. In exchange, zoos would be expected to provide funds or support ‘in kind’ for the camps or for the conservation of wild elephants. Most of the elephants in the Sumatran camps were captured because of crop‐raiding problems around protected areas or because elephant habitat has been and continues to be lost to development schemes and illegal conversion of protected areas to agriculture. Capture‐related mortality rates are high and conditions in the camps are poor, with low standards of veterinary care and husbandry. This is partly due to over‐crowding and inadequate budgets. It might seem, therefore, that the loan of elephants to western zoos would improve the lot of these elephants and reduce the pressures on the camps. However, we show that both total and annual demand for Asian elephants, and particularly Sumatran elephants (E. m. sumatranus), by western zoos are low, and consequently the resources generated by any loan scheme would be limited. Elephant loan schemes are unlikely to have significant beneficial impact on either the conservation or welfare of elephants in Sumatra. More importantly, a credible loan scheme would require a permanent moratorium on the capture of wild elephants in Sumatra. Such a moratorium is needed to prevent illicit captures for sale or loan. At present, wild elephants are caught to replace those that die at the camps or are moved to other facilities. Without a moratorium, the loan of elephants to overseas zoos would contribute directly to reductions in wild elephant populations in Sumatra. However, a moratorium is likely to prove impossible to enforce, and this alone should call into question the desirability of any loan scheme. Zoo Biol 25:235–246, 2006. © 2006 Wiley‐Liss, Inc.  相似文献   

10.
Dogs (Canis familiaris) are used in hunting white-tailed deer (Odocoileus virginianus) in 10 North American jurisdictions. Although the practice is longstanding and controversial, the effects of dogs on the outcome of the hunt have rarely been studied. We evaluated the influence of dogs on recreational hunting of white-tailed deer based on long-term data from southeastern Ontario, Canada. Over 25 years, annual surveys of hunters were used to collect data on hunting effort and deer harvest from approximately 85 camps, roughly half of which had dogs. We investigated the relationship between harvest and 3 treatments (i.e., 0 dogs, 1 dog, and ≥2 dogs in camp), interactions with weather and deer density, and effects of neighboring camps. Dogs enhanced hunter success. We found no difference in deer encounter rates but, per unit effort, camps with ≥2 dogs harvested 0.013 (26%) more deer per hunter-day, missed 0.010 (23%) more deer per hunter-day, and wounded 0.002 (40%) more deer per hunter-day than camps without dogs. Conversely, camps without dogs saw, without shooting at, 0.033 (23%) more deer per hunter-day than camps with ≥2 dogs. These results are consistent with the idea that hunters with dogs are less selective. Hunters with dogs harvested more fawns per unit effort, but we found no difference in the harvest rate of older female deer. More precipitation, greater wind speed, lower temperatures and greater deer density improved harvest success but had no differential effect among dog treatments. Hunter success at camps with ≥2 dogs was less when neighboring camps also had ≥2 dogs. Because antlerless deer quotas are the principal means to control populations, increasing use of hunting dogs is unlikely to have substantial effects in managing overabundant deer. © 2012 The Wildlife Society.  相似文献   

11.
This paper adapts the removal method of population size estimation to the problem of estimating the size of the western Arctic stock of bowhead whales. The whales are counted during their spring migration as they pass two census camps located near Point Barrow, Alaska. Whales seen at the first camp are "removed" from the population of concern to the second camp, where only whales missed by the first camp are counted. If both camps were in operation throughout the migration and if the probability of missing a whale were constant, the removal method would provide a population size estimate based on a trinomial model in which the size of the population would be the number of trials, whales counted by each camp would provide the observed cell totals, and whales missed by both camps would represent an unobserved cell total. Since the probability of missing a whale depends on visibility, we model the population size as the sum of the number of trials of several independent trinomial distributions, each of which represents a particular visibility condition occurring during the census. To account for the fact that watch cannot be maintained at both camps throughout the migration, we derive a confidence interval estimate of the number of trials under a more general model allowing for incomplete observation of totals within particular cells as well as for completely unobserved cells.  相似文献   

12.
In recent years, the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) has attempted to go beyond its role as a provider of relief and basic services in Palestinian refugee camps and emphasize its role as a development agency. In this article, I focus on the Neirab Rehabilitation Project, an UNRWA-sponsored development project taking place in the Palestinian refugee camps of Ein el Tal and Neirab in northern Syria. I argue that UNRWA's role as a relief-centered humanitarian organization highlights the everyday suffering of Palestinian refugees, suffering that has become embedded in refugees’ political claims. I show that UNRWA's emphasis on “development” in the refugee camps is forcing Palestinian refugees in Ein el Tal and Neirab to reassess the political narrative through which they have understood their relationship with UNRWA.  相似文献   

13.
Docosahexaenoic acid (DHA) is the longest, most unsaturated, and hence, most oxidizable fatty acid commonly found in nature. The mechanisms behind DHA's many biological functions remain a subject of much debate. Here we review one important, but often unstudied, aspect of DHA function, namely, the potential role of its many oxidation products. We divide this review into camps, enzymatic and non-enzymatic oxidations, and report their effects primarily on induction of apoptosis in cancer cells. We conclude that the study of the effects of lipid peroxidation products on biochemical function will be a difficult but highly rewarding area for future studies.  相似文献   

14.
In the gastrointestinal tract, CFTR, in conjunction with one or several members of the SLC26 anion exchanger family, mediates electrogenic Cl- and HCO3- secretion. Na+/H+ exchanger isoform NHE3, on the other hand, coupled to one or several of the SLC26 isoforms, mediates electroneutral NaCl absorption. The agonist-induced activation of anion secretion and inhibition of salt absorption causes secretory diarrhea. Current dogma sees the formation of a multiprotein complex of transport proteins, postsynaptic density-95/discs large/zonula occludens-1 (PDZ) adapter proteins, anchoring proteins, the cytoskeleton, and the involved protein kinases as one crucial step in the regulation of these transport processes. Data obtained in heterologous expression studies suggest an important role of these PDZ adapter proteins in trafficking, endocytic recycling, and membrane retention of the respective transmembrane proteins. This article reviews recent advances in our understanding of the role of the PDZ adapter proteins NHERF, E3KARP, PDZK1, IKEPP (NHERF-1 to NHERF-4), CAL, and Shank-2 that bind to CFTR, NHE3, and the intestinal SLC26 members in the regulation of intestinal fluid transport. Current concepts are mostly derived from heterologous expression studies and studies on their role in organ physiology are still in infancy. Recently, however, PDZ adapter protein-deficient mice and organ-specific cell lines have become available, and the first results suggest a more cell-type and possibly signal-specific role of these adapter proteins. This opens the potential for drug development targeted to PDZ domain interactions, which is, in theory, one of the most efficient antidiarrheal strategies.  相似文献   

15.
Urbanisation of wildlife populations is a process with significant conservation and management implications. While urban areas can provide habitat for wildlife, some urbanised species eventually come into conflict with humans. Understanding the process and drivers of wildlife urbanisation is fundamental to developing effective management responses to this phenomenon. In Australia, flying-foxes (Pteropodidae) are a common feature of urban environments, sometimes roosting in groups of tens of thousands of individuals. Flying-foxes appear to be becoming increasingly urbanised and are coming into increased contact and conflict with humans. Flying-fox management is now a highly contentious issue. In this study we used monitoring data collected over a 15 year period (1998–2012) to examine the spatial and temporal patterns of association of spectacled flying-fox (Pteropus conspicillatus) roost sites (camps) with urban areas. We asked whether spectacled flying-foxes are becoming more urbanised and test the hypothesis that such changes are associated with anthropogenic changes to landscape structure. Our results indicate that spectacled flying-foxes were more likely to roost near humans than might be expected by chance, that over the period of the study the proportion of the flying-foxes in urban-associated camps increased, as did the number of urban camps. Increased urbanisation of spectacled flying-foxes was not related to changes in landscape structure or to the encroachment of urban areas on camps. Overall, camps tended to be found in areas that were more fragmented, closer to human habitation and with more urban land cover than the surrounding landscape. This suggests that urbanisation is a behavioural response rather than driven by habitat loss.  相似文献   

16.
17.
The Regulator of Chromosome Condensation 1 (RCC1) was identified over 20 years ago as a critical cell cycle regulator. By analyzing its amino acid sequence, RCC1 was found to consist of seven homologous repeats of 51-68 amino acid residues, which were later shown to adopt a seven-bladed beta-propeller fold. Since the initial identification of RCC1, a number of proteins have been discovered that contain one or more RCC1-like domains (RLDs). As we show here, these RCC1 superfamily proteins can be subdivided in five subgroups based on structural criteria. In recent years, a number of studies have been published regarding the functions of RCC1 superfamily proteins. From these studies, the emerging picture is that the RLD is a versatile domain which may perform many different functions, including guanine nucleotide exchange on small GTP-binding proteins, enzyme inhibition or interaction with proteins and lipids. Here, we review the available structural and functional data on RCC1 superfamily members, paying special attention to the human proteins and their involvement in disease.  相似文献   

18.
The gel-forming mucins are large and heavily O-glycosylated proteins which build up mucus gels. The recombinant production of full-length gel-forming mucins has not been possible to date. In order to study mucin biosynthesis and biochemistry, we and others have taken the alternative approach of constructing different recombinant proteins consisting of one or several domains of these large proteins and expressing them separately in different cell lines. Using this approach, we have determined that MUC2, the intestinal gel-forming mucin, dimerizes via its C-terminal cysteine-knot domain and also trimerizes via one of the N-terminal von Willebrand D domains. Both of these interactions are disulfide bond mediated. Via this assembly, a molecular network is built by which the mucus gel is formed. Here we discuss not only the functional understanding obtained from studies of the recombinant proteins, but also highlight the difficulties encountered when these proteins were produced recombinantly. We often found an accumulation of the proteins in the ER and consequently no secretion. This was especially apparent when the cysteine-rich domains of the N- and C-terminal parts of the mucins were expressed. Other proteins that we constructed were either not secreted or not expressed at all. Despite these problems, the knowledge of mucin biosynthesis and assembly has advanced considerably through the studies of these recombinant proteins.  相似文献   

19.
Double-stranded DNA breaks (DSBs) are a particularly dangerous form of DNA damage because they can lead to chromosome loss, translocations or truncations. When DSBs occur, many proteins are recruited to the break site; these proteins serve to both initiate DNA repair and to activate a checkpoint response. Repair occurs via one of two pathways: non-homologous end-joining (NHEJ), in which broken DNA ends are directly ligated; or homologous recombination (HR), in which a homologous chromosome is used as a template in a replicative repair process. The checkpoint response is mediated by the phosphatidyl inositol 3-kinase-like kinases, Mec1 and Tel1 (ATR and ATM in humans, respectively). Two recent studies in yeast have significantly increased our understanding of when each of the proteins involved in these processes is localized to a break and, in addition, how their sequential localization is achieved. Specifically, these studies support and expand upon a model in which Tel1 and the NHEJ proteins are the first proteins to localize to the break to initiate signaling and attempt repair, but are subsequently replaced by Mec1 and the HR proteins. This transition is mediated by a cyclin-dependent kinase-dependent initiation of 5'-->3' processing (resection) of the DSB. Thus, the cell-cycle stage at which DSBs occur affects the way in which the DSBs are processed and recognized.  相似文献   

20.
Sorting of proteins to vacuoles in plant cells   总被引:11,自引:0,他引:11  
An individual plant cell may contain at least two functionally and structurally distinct types of vacuoles: protein storage vacuoles and lytic vacuoles. Presumably a cell that stores proteins in vacuoles must maintain these separate compartments to prevent exposure of the storage proteins to an acidified environment with active hydrolytic enzymes where they would be degraded. Thus, the organization of the secretory pathway in plant cells, which includes the vacuoles, has a fascinating complexity not anticipated from the extensive genetic and biochemical studies of the secretory pathway in yeast. Plant cells must generate the membranes to form two separate types of tonoplast, maintain them as separate organelles, and direct soluble proteins from the secretory flow specifically to one or the other via separate vesicular pathways. Individual soluble and membrane proteins must be recognized and sorted into one or the other pathway by distinct, specific mechanisms. Here we review the emerging picture of how separate plant vacuoles are organized structurally and how proteins are recognized and sorted to each type.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号