969 resultados para bottom walkers
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Solving the water crisis in the developing world is a critical issue. Four billion people in the globe, so called the Base of the Pyramid (BoP) population suffer from inadequate access to safe drinking water, while millions die daily from waterborne diseases and lack of clean water. The BoP people desperately need to obtain a satisfactory access to safe water sources. In order to address the issue, this research has been carried out. To provide holistic consideration to the matter, comprehensive exploration of various causes of the water crisis and its impacts in developing countries were discussed. Then, various viable and relevant solutions to the problem have been thoroughly scrutinized, including scientific, rational, practical and speculative approaches, examination of existing methods, technologies and products at the BoP water market. The role of clean water to the sustainable development was specifically featured. The paper also has studied social and economic factors, actors and circumstances which affect the market development of clean water technologies in the BoP. Possibilities and potentials of successful business between foreign water enterprises and BoP consumers were considered, while primary obstacles are deliberated on, with suggestion of the ways to tackle them. Technologies and products which are needed by the poor must be affordable, sustainable and of an appropriate quality. The crucial question of technology transfer was soundly discussed with pointing out main hindrances on the way of its implementation between the developed and developing world. The means to overcome these barriers were properly observed as well. To explore to some extent the possibility and feasibility of technology transfer from Finland to the BoP sector, 3 case study analyses have been implemented. Personal discussions in form of interviews were conducted at Kemira, Outotec and Fenno Water, Finnish water treatment and supply enterprises. The results of the interviews shed light on the specific practical matters, actual obstacles and potential solutions of the technology transfer from Finland to low-income countries.
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In this thesis, three main questions were addressed using event-related potentials (ERPs): (1) the timing of lexical semantic access, (2) the influence of "top-down" processes on visual word processing, and (3) the influence of "bottom-up" factors on visual word processing. The timing of lexical semantic access was investigated in two studies using different designs. In Study 1,14 participants completed two tasks: a standard lexical decision (LD) task which required a word/nonword decision to each target stimulus, and a semantically primed version (LS) of it using the same category of words (e.g., animal) within each block following which participants made a category judgment. In Study 2, another 12 participants performed a standard semantic priming task, where target stimulus words (e.g., nurse) could be either semantically related or unrelated to their primes (e.g., doctor, tree) but the order of presentation was randomized. We found evidence in both ERP studies that lexical semantic access might occur early within the first 200 ms (at about 170 ms for Study 1 and at about 160 ms for Study 2). Our results were consistent with more recent ERP and eye-tracking studies and are in contrast with the traditional research focus on the N400 component. "Top-down" processes, such as a person's expectation and strategic decisions, were possible in Study 1 because of the blocked design, but they were not for Study 2 with a randomized design. Comparing results from two studies, we found that visual word processing could be affected by a person's expectation and the effect occurred early at a sensory/perceptual stage: a semantic task effect in the PI component at about 100 ms in the ERP was found in Study 1 , but not in Study 2. Furthermore, we found that such "top-down" influence on visual word processing might be mediated through separate mechanisms depending on whether the stimulus was a word or a nonword. "Bottom-up" factors involve inherent characteristics of particular words, such as bigram frequency (the total frequency of two-letter combinations of a word), word frequency (the frequency of the written form of a word), and neighborhood density (the number of words that can be generated by changing one letter of an original word or nonword). A bigram frequency effect was found when comparing the results from Studies 1 and 2, but it was examined more closely in Study 3. Fourteen participants performed a similar standard lexical decision task but the words and nonwords were selected systematically to provide a greater range in the aforementioned factors. As a result, a total of 18 word conditions were created with 18 nonword conditions matched on neighborhood density and neighborhood frequency. Using multiple regression analyses, we foimd that the PI amplitude was significantly related to bigram frequency for both words and nonwords, consistent with results from Studies 1 and 2. In addition, word frequency and neighborhood frequency were also able to influence the PI amplitude separately for words and for nonwords and there appeared to be a spatial dissociation between the two effects: for words, the word frequency effect in PI was found at the left electrode site; for nonwords, the neighborhood frequency effect in PI was fovind at the right elecfrode site. The implications of otir findings are discussed.
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The Feedback-Related Negativity (FRN) is thought to reflect the dopaminergic prediction error signal from the subcortical areas to the ACC (i.e., a bottom-up signal). Two studies were conducted in order to test a new model of FRN generation, which includes direct modulating influences of medial PFC (i.e., top-down signals) on the ACC at the time of the FRN. Study 1 examined the effects of one’s sense of control (top-down) and of informative cues (bottom-up) on the FRN measures. In Study 2, sense of control and instruction-based (top-down) and probability-based expectations (bottom-up) were manipulated to test the proposed model. The results suggest that any influences of medial PFC on the activity of the ACC that occur in the context of incentive tasks are not direct. The FRN was shown to be sensitive to salient stimulus characteristics. The results of this dissertation partially support the reinforcement learning theory, in that the FRN is a marker for prediction error signal from subcortical areas. However, the pattern of results outlined here suggests that prediction errors are based on salient stimulus characteristics and are not reward specific. A second goal of this dissertation was to examine whether ACC activity, measured through the FRN, is altered in individuals at-risk for problem-gambling behaviour (PG). Individuals in this group were more sensitive to the valence of the outcome in a gambling task compared to not at-risk individuals, suggesting that gambling contexts increase the sensitivity of the reward system to valence of the outcome in individuals at risk for PG. Furthermore, at-risk participants showed an increased sensitivity to reward characteristics and a decreased response to loss outcomes. This contrasts with those not at risk whose FRNs were sensitive to losses. As the results did not replicate previous research showing attenuated FRNs in pathological gamblers, it is likely that the size and time of the FRN does not change gradually with increasing risk of maladaptive behaviour. Instead, changes in ACC activity reflected by the FRN in general can be observed only after behaviour becomes clinically maladaptive or through comparison between different types of gain/loss outcomes.
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Neural models of the processing of illusory contour (ICs) diverge from one another in terms of their emphasis on bottom-up versus top-down constituents. The current study uses a dichoptic fusion paradigm to block top-down awareness of ICs in order to examine possible bottom-up effects. Group results indicate that the N170 ERP component is particularly sensitive to ICs at central occipital sites when top-down awareness of the stimulus is permitted. Furthermore, single-subject statistics reveal that the IC N170 ERP effect is highly variable across individuals in terms of timing and topographical spread. The results suggest that the ubiquitous N170 effect to ICs found in the literature depends, at least in part, on participants’ awareness of the stimulus. Therefore a strong bottom-up model of IC processing at the time of the N170 is unlikely.
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Publié par la Revue de droit d'Ottawa.
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Variations of the infaunal polychates populations due to bottom trawling were studied during December 2000 to November 2002 at depth ranging from 0-50 m along Cochin-Munambam area (Kerala, long. 76degree10'94" to 75degree 56' and lat.9degree58' to 10degree10'), in the southwest coast of India.Infaunal polychaetes from the sediment samples were collected both before and after experimental trawling in order to assess the variations on their abundance (no.m-2),biomass(g.m-2) and diversity due to bottom trawling .Highest variations in polychaetes were recorded at station 9 in May 2002 where polychaete abundance increased to 20710 no.m-2 after trawling from 2787 no.m-2 before trawling.Biomass showed highest variations at station 3 in December 2000 where biomass increased from 7.16g.m-2 recorded before trawling to 34.53 g.m-2 in the samples collected after trawling .Multivariate community analysis carried out based on both species abundance and biomass of plychaetes also confirm the wide variations in the similarities of the stations comparing both before and after trawling
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School of Industrial Fisheries, Cochin University of Science and Technology
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Bottom trawling is one among the most destructive human induced physical disturbances inflicted to seabed and its living communities. The bottom trawls are designed to tow along the sea floor, which on its operation indiscriminately smashes everything on their way crushing, killing, burying and exposing to predators the benthic fauna. Bottom trawling causes physical and biological damages that are irreversible, extensive and long lasting. The commercial trawling fleet of India consists of 29,241 small and medium-fishing boats. The northwest coast of India has the largest fishing fleet consisting of 23,618 mechanized vessels, especially the bottom trawlers. However, attempts were not made to study the impact of bottom trawling along Northwest coast of India. The estimated optimum fleet size of Gujarat is 1,473 mechanised trawlers while 7402 commercial trawlers are operated from the coast of Gujarat. Veraval port was designed initially for 1,200 fishing trawlers but 2793 trawlers are being operated from this port making it the largest trawler port of Gujarat. The aim of this study was to investigate the effects of bottom trawling on the substratum and the associated benthic communities of commercial trawling grounds of Veraval coast. The study compared the differences between the samples collected before and after experimental trawling to detect the impacts of bottom trawling. Attempts were made to assess the possible impact of bottom trawling on:(i) the sediment characteristics (ii)the sediment heavy metals (iii) epifauna (iv) macrobenthos and (v) meiobenthos. This study is expected to generate information on trawling impacts of the studied area that will help in better management of the biological diversity and integrity of the benthic fauna off Veraval coast. An exhaustive review on the studies conducted around the world and in India on impact of bottom trawling on the benthic fauna is also detailed.In the present study, the bottom trawling induced variations on sediment organic matter, epifauna, macrobenthos and meiobenthos were evident. It was also observed that the seasonal/ natural variations were more prominent masking the trawling effect on sediment texture and heavy metals. Enforcement of control of excess bottom trawlers and popularization of semi pelagic trawls designed to operate a little distance above the sea bottom for off bottom resources will minimize disturbance on the sea bottom. Training and creating awareness in responsible fishing should be made mandatory requirements, to the coastal communities. They should be made wardens to protect the valuable resources for the benefit of sustainability. To protect the biodiversity and ecosystem health, the imminent need is to survey and make catalogue, identification of sensitive areas or hot spots and to adopt management strategies for the conservation and biodiversity protection of benthic fauna. The present study is a pioneering work carried out along Veraval coast. This thesis will provide a major fillip to the studies on impact of bottom trawling on the benthic fauna along the coast of India.
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Mechanized fishing started in Indian waters in mid —fifties and large-scale operation of trawl fishing began in the mid sixties by the surfeit of individual entrepreneurs. The southwest coast of India especially the coastal waters of Kerala are the most productive area in the subcontinent and the state has been in the forefront in marine fish production (Kurup, 2001a). Though the coastline of Kerala is one tenth of the coastline of India, the state occupies the foremost position in the marine fish production of the country, accounting for more than 30% of the marine fish landings (Thomas, 2000). The coastal waters of Kerala have rich and diversified fishery resources, which are prone to heavy exploitation by a unprecedently high number of fishing gears, among them, mechanized bottom trawlers with a numerical strength of 4550 (Kurup, 2001a) against the permissible number of 1145 (Kalawar, et al., 1985) are the most destructive. Trawling operations during monsoon periods in Kerala has been a subject of controversy between traditional fishermen and trawl fishers on a subject that trawl fishing destroys large amount of juveniles and young ones of fishes since this period is the major breeding season of most of the fish and prawns (John, 1996). Therefore Government of Kerala imposed a ban on bottom trawling activities from 1988 onwards for a period varying from 21-70 days, which usually commences from June 15th. Though many studies revealed that large amount of non-target groups were destroyed in the commercial trawl fishing in the Indian waters, no concerted study has been conducted so far to evaluate the real impact of bottom trawling on the sea bottom and its living communities. The present study was conducted to assess the impact of excessive bottom trawling exerted on the sea bottom habitat and its living communities, which would be useful in impressing up on the seriousness of habitat degradation and biotic devastation, enabling the concerned to adopt relevant conservation and management steps to conserve the resources for sustainable exploitation
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Hydrographic characteristics of the southwest coast of India and its adjoining Cochin backwaters (CBW) were studied during the summer monsoon period. Anomalous formation of anoxia and denitrification were observed in the bottom layers of CBW, which 5 have not been previously reported elsewhere in any tropical estuarine systems. The prevalent upwelling in the Arabian Sea (AS) brought cool, high saline, oxygen deficient and nutrient-rich waters towards the coastal zone and bottom layers of CBW during the high tide. High freshwater discharge in the surface layers brought high amount of nutrients and makes the CBW system highly productive. Intrusion of AS waters seems 10 to be stronger towards the upstream end ( 15 km), than had been previously reported, as a consequence of the lowering of river discharges and deepening of channels in the estuary. Time series measurements in the lower reaches of CBW indicated a low mixing zone with increased stratification, 3 h after the high tide (highest high tide) and high variation in vertical mixing during the spring and neap phases. The upwelled waters 15 (O2 40 μM) intruded into the estuary was found to lose more oxygen during the neap phase (suboxic O2 4 μM) than spring phase (hypoxic O2 10 μM). Increased stratification coupled with low ventilation and presence of high organic matter have resulted in an anoxic condition (O2 = 0), 2–6 km away from barmouth of the estuary and leads to the formation of hydrogen sulphide. The reduction of nitrate and formation of nitrite 20 within the oxygen deficient waters indicated strong denitrification intensity in the estuary. The expansion of oxygen deficient zone, denitrification and formation of hydrogen sulphide may lead to a destruction of biodiversity and an increase of green house gas emissions from this region
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The paper deals with some relevant and contradictory aspects of urban and peri-urban agriculture in Italy: the traditional exclusion of agricultural areas from the goals of territorial planning; the separation between top-down policies and bottom-up practices; the lack of agricultural policies at local scale. In the first part the paper summarises the weak relation between urban planning and agriculture, showing how in Italy this gap has been only partially overcome by new laws and plans. Moreover the paper focuses on how, due to the lack of suitable solutions coming from regional and local planning, a large number of vibrant initiatives were started by local stakeholders. In order to show the limitations and the potentialities of these various approaches, three peculiar experiences based on Milan, Turin and Pisa are presented. They give a cross-section of the variegated Italian situation, demonstrating that a major challenge in Italian context affects the fields of governance and inclusiveness.
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Since pre-colonial times the indigenous communities of Mayan origin in the state of Quintana Roo, Mexico, widely practice home gardens on a sustainable basis as the principal form of family agriculture. This study analyzes the structural complexity, functional diversity and management strategy of these indigenous home gardens in order to attempt to propose recommendations for improved family farming. The Mayan home gardens are structured into three or more vertical layers of multiple plant species of herbs, shrubs and trees, and horizontally into well-defined zones for production of both domestic and wild animals. The home gardens provide multiple services apart from food and nutrition security. For sustainable bottom-up rural development, we recommend the continuation of multifunctional home gardens.