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1.
Dams are widely recognised as having significant negative consequences for the surrounding natural ecosystems and environment. China’s Three Gorges Dam, being one of the largest in the world, stands to inflict more damage than most for numerous reasons. This paper reviews the current knowledge on the impacts of dams and impoundments with regard to reservoir riparian vegetation in order to apply this knowledge to the Three Gorges Project. It also summarises research performed to date on the effects of the Three Gorges Dam on the local riparian zone and vegetation. The known and potential outcomes for local plant communities are examined in terms of their responses to the increased water levels, altered hydrological characteristics and other adverse effects associated with the construction of the dam. Vegetation responses will be diverse and change over time, but will ultimately result in a markedly different landscape and riparian zone within the Three Gorges Reservoir. These changes will take place through a loss of previous vegetation, potential invasion by exotics and result from the significant alteration in hydrological regimes and also erosion and sedimentation processes influencing and creating novel plant communities. Management of the environmental consequences of the Three Gorges Project should take into account factors associated with these processes, in order to facilitate vegetation recovery in the reservoir and to conserve biodiversity of the surrounding ecosystems.  相似文献   

2.
As three of the members of the delegation of the Botanical Society of America, the authors participated in a 28-day tour of the People’s Republic of China in May and June, 1978. Botanical institutes and universities were visited in nine cities. A list of names and addresses of the collaborators and editors of family treatments for theFlora Reipublicae Popularis Sinicae is supplemented with a bibliography of published floras and significant taxonomic literature issued primarily since the end of the Cultural Revolution. A few observations on herbaria and herbarium practices are included.  相似文献   

3.
Hong Kong is famous as a bustling harbour and financial centre, with a dense burgeoning population impacting its coastal environment. Yet, away from the skyscrapers and the pressures of anthropogenic influence, Hong Kong supports a rich marine biodiversity, including corals and mangrove communities. Despite having a small marine area (1651 km2), a total of 5943 marine species have been recorded in Hong Kong waters. Most of these species were reported during the 1980s and 1990s, but new species continue to be discovered, and ~6500 species are estimated. Even though Hong Kong’s marine area is only ~0.03 % of that of China, the number of marine species recorded in Hong Kong already accounts for ~26 % of the total recorded in China. Hong Kong also contributes to a considerable amount (>30 %) of the species records for several taxa including amphipods, cephalopods, polychaetes and fish in the South China Sea, and ~29 % of the hermit crab species in the largest global marine species database, the World Register of Marine Species. These findings demonstrate the rich marine biota found in Hong Kong, which probably reflects Hong Kong’s location within the fringes of the world’s marine biodiversity hotspot.  相似文献   

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Little is known about the vegetation found in the karst springs of Wisconsin’s unglaciated region, the Driftless Area. We sampled 26 of these springs, documenting all associated plant species and their status (native, non-native, invasive) and analyzed whether vegetation patterns are related to spring orientation or to spring area. Two-way ANOVA results show that non-native and invasive species, namely Nasturtium officinale (watercress, Brassicaceae), are significantly more abundant than natives in north-facing springs (p < 0.01), but not in south-facing springs. Generally, native species are restricted to, or more abundant in, south-facing springs, and may have a microtopographical preference for these sites, which may receive more direct solar radiation. Nasturtium officinale, the most abundant invasive species, has high cover values in both north and south orientations and is less restricted in its distribution. Correlation analysis shows that the larger the spring, the higher the percent of Nasturtium (p < 0.01) and invasive species cover (as a percent of spring area) (p < 0.005). Larger springs often had slower moving water and this may have contributed to the success of Nasturtium, which may outcompete shade-intolerant natives in the larger springs. Native species cover was negatively related to spring area, though this result was marginally insignificant (p = 0.08).  相似文献   

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Chinese and Russian scientific literature is reviewed, research centers studying pathology of fish and of other aquatic organisms are pointed out. Comparative analysis of scientific problems and of objects of the laboratories and institutes of Russian and China is made. Our original data are presented on the rapid method of early diagnosis of fish diseases.  相似文献   

9.
Amy Ninetto 《Ethnos》2013,78(4):443-464
Through a comparison of privatization programs in two physics institutes, this article explores the ways in which scientists in the Siberian science city of Akademgorodok adapted to the low levels of state funding available to them in the 1990s. Scientists transformed structures that were available under socialism into hybrid state-private ventures. Rather than ‘freeing’ Russian science from its former dependence on the state, however, these changes have reconfigured, and in some cases even strengthened, the relationship between state power and the production of knowledge. Seeing ‘the state’ as it is constituted in Russian scientists' discourse challenges Western models of the autonomy of science.  相似文献   

10.
Forests play a major role in global carbon (C) cycle, and the carbon density (CD) could reflect its ecological function of C sequestration. Study on the CD of different forest types on a community scale is crucial to characterize in depth the capacity of forest C sequestration. In this study, based on the forest inventory data of 168 field plots in the study area (E 111°30′–113°50′, N 37°30′–39°40′), the forest vegetation was classified by using quantitative method (TWINSPAN); the living biomass of trees was estimated using the volume-derived method; the CD of different forest types was estimated from the biomass of their tree species; and the effects of biotic and abiotic factors on CD were studied using a multiple linear regression analysis. The results show that the forest vegetation in this region could be classified into 9 forest formations. The average CD of the 9 forest formations was 32.09 Mg ha−1 in 2000 and 33.86 Mg ha−1 in 2005. Form. Picea meyeri had the highest CD (56.48 Mg ha−1), and Form. Quercus liaotungensis Acer mono had the lowest CD (16.14 Mg ha−1). Pre-mature forests and mature forests were very important stages in C sequestration among four age classes in these formations. Forest densities, average age of forest stand, and elevation had positive relationships with forest CD, while slope location had negative correlation with forest CD.  相似文献   

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Background

Congenital malformations of the seminal vesicle are uncommon, and most of them are cystic malformations. If an insult occurs between the 4th and the 13 h gestational week, the embryogenesis of the kidney, ureter, seminal vesicle, and vas deferens could be altered. Cysts of the seminal vesicle may appear with a mass effect, dysuria, epididymitis, or obstruction of the gastrointestinal and genitourinary tracts. Approximately two thirds of them are associated with ipsilateral renal agenesis, because both the ureteral buds and seminal vesicles originate from the mesonephric (Wolffian) duct. They were first described by Zinner in 1914, and 200 cases of seminal vesicle cysts associated with ipsilateral renal agenesis have been reported in the literature. Most patients with this anomaly are asymptomatic until the third or fourth decade of life. Some cases have nonspecific symptoms such as prostatism, urinary urgency, dysuria, painful ejaculation, and perineal discomfort. Transrectal ultrasonography provides good visualization of the pelvic structures and allows guidance for aspiration of the cysts.

Case presentation

We present two cases of seminal vesicle cyst. The first patient had dysuria, increased frequency of urination, and haematuria. He was operated and benefited from a removal of the cyst with right ureterectomy and left ureteral reimplantation. The second patient had disorder of the digestive transit and he benefited from a laparoscopic removal of the cyst.

Conclusions

Seminal vesicle cysts combined with ipsilateral renal agenesis are rare urological anomalies. Usual symptoms that are caused by the seminal vesicle cysts are bladder irritation and obstruction as well as pain in the perineum and scrotum. Epididymitis is frequently found. Treatment consists to removing the seminal vesicle cyst.
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ABSTRACT

Studies of the environmental spirit world have been pursuing two main lines of inquiry: (1) that indigenous claims on ecological thought, including beliefs in chthonic spirits and mountain deities, are the outcome of a global process of abstraction and the commoditisation of nature which acts as technology of governmentality for the production of discursive formations through which neoliberal environmental subjectivities can emerge and (2) that the pitfalls of the nature/culture dualism can be avoided by giving priority to nonhuman subjectivities and positing sociologies of nature as subordinate to ontologies of the self-other divide or action-orienting cosmologies of local ‘nature’. The contributors of this collection engage with the spirit worlds and other invisible agents that constitute the everyday landscape of a number of ethnic groups in western China. While declining to engage with the notion of animism or subscribing to totalising ‘cosmologies’, the authors prefer to extract the eventfulness of haphazard and radically uncertain interactions with spirits or wondrous signs apt to be transformed into marvels and rumours. The ethnographies presented in this collection reveal an eventology of spirit worlds and landscape on China’s borderlands, an inquiry that – unlike history – does not study ‘events’ as such but the relation between what is deemed to be an event, a surprise, or a manifestation of wonder and what is deemed to be the innate, natural, ordinary, everyday life.  相似文献   

15.
Michael Hanchard’s the Spectre of Race: How Discrimination Haunts Western Democracy is a sophisticated examination of the disciplinary absence and seething presence of race in the subfield and substance of comparative politics. Hanchard’s analysis reveals a genealogy of how certain concepts, such as political culture, came to be institutionalized in the discipline. Because disciplines discipline, the resultant marginalization of race in comparative politics is itself an act of power. Many of his insights are revelatory, though a more explicit excavation of racial transnationalism is warranted. Such an effort would: first, demonstrate that the transnational “entanglements” Hanchard details are even more knotted than originally presumed; second, challenge the conflation of racialization and colonialism; and third, question whether liberal democratic inclusion is possible or even worth the price of the ticket.  相似文献   

16.
Littorals in the in the Exuma Cays, Bahamas and the Bath Plantation, Barbados are comparative in many ways. These edges of the sea have provided critical services to local people during the time of slavery and since. More than food and medicine, the littoral is the nightly sea bath, where children are instructed, and the last ecosystem effectively used by the elderly. Independence and self-respect derive from use and protection of these littoral by individuals and communities. Local patterns of conservation and use are argued to be essential in the ecological structure and functions of the littoral. Development projects and marine protected areas alike are seen as potentially breaking local ties with the littoral causing trophic skew and damaging local society. If development occurs, mitigation solutions potentially derive from legally recognizing local people as partners in the co-management of their traditional littoral.
Richard W. Stoffle (Corresponding author)Email:
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Disbalance of zinc (Zn2+) and copper (Cu2+) ions in the central nervous system is involved in the pathogenesis of numerous neurodegenerative disorders such as multisystem atrophy, amyotrophic lateral sclerosis, Creutzfeldt-Jakob disease, Wilson-Konovalov disease, Alzheimer’s disease, and Parkinson’s disease. Among these, Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the most frequent age-related neurodegenerative pathologies with disorders in Zn2+ and Cu2+ homeostasis playing a pivotal role in the mechanisms of pathogenesis. In this review we generalized and systematized current literature data concerning this problem. The interactions of Zn2+ and Cu2+ with amyloid precursor protein (APP), β-amyloid (Abeta), tau-protein, metallothioneins, and GSK3β are considered, as well as the role of these interactions in the generation of free radicals in AD and PD. Analysis of the literature suggests that the main factors of AD and PD pathogenesis (oxidative stress, structural disorders and aggregation of proteins, mitochondrial dysfunction, energy deficiency) that initiate a cascade of events resulting finally in the dysfunction of neuronal networks are mediated by the disbalance of Zn2+ and Cu2+.  相似文献   

19.
The essay attempts to delineate how Maurice Merleau-Ponty’s phenomenology of perception can be applied to theories of sign processes, and how it reworks the framework of the phenomenalist conception of communication. His later philosophy involved a reformulation of subjectivity and a resolution of the subject/object dualism. My claim is that this non-reductionist theory of perception reveals a different view of nature as we experience it in an expressive and meaningful interaction. The perspective that another living being has and communicates entails a form of depth, the invisible dimension of the visible or audible. These two aspects of perception and dialogue are intertwined in a dialectic of presence and absence, so that sense arises in the perceptual field rather than in subjectivity. This, I argue, is the most fundamental result of his theory. The origination of meaning in the workings of the chiasm of visible and invisible in perception opens up an objective sense of intersubjective nature. The essay also deals with the role of the phenomenological reduction; a suspension of beliefs and existence claims in experience. The reduction enables us to take a step back and look more closely at our understanding of nature in light of the historical and cultural influence on our thinking.  相似文献   

20.
Due to its public popularity, ornithology has a huge corpus of scientific publication for a relatively small number of species. Although there are global checklists of currently recognised taxa, there has been only limited, mainly individual, effort to build a nomenclatural database that the science of ornithology deserves. This is especially true in relation to concise synonymies. With the arrival of ZooBank and the Biodiversity Heritage Library, the time has come to develop synonymies and to add fuller bibliographic detail to databases. The preparation for both began at the start of the 20th century with extensive work by Sherborn and Richmond. I discuss their legacy, offer notes on significant work since then, and provide suggestions for what remains to be done. To make solid the foundations for ornithological nomenclature and taxonomy, especially for synonymies, ornithologists will need to collaborate much more and contribute to the digital infrastructure.  相似文献   

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