853 resultados para Congestion recovery
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Questions - Are the germinable seed banks of upland heath and blanket bog reduced following wildfires? Are some species at particular risk? Do the impacts of wildfires on seed banks differ between heathlands and blanket bog?
Location - Northern Ireland, United Kingdom.
Methods - Vegetation surveys and seed bank sampling were conducted in 2012 at burned and unburned areas within six upland sites where large wildfires had occurred during spring 2011. Differences in seedling abundance, species richness and Jaccard similarity indices between burned and unburned areas were compared using GLMMs. Differences in the community composition were examined using pRDA.
Results - In total, 24 of the 51 species in the vegetation were detected in the germinable seed bank. Species richness and the abundance of seedlings other than Calluna vulgaris were lower in areas where wildfires had occurred. Species composition of both germinable seed banks and vegetation differed between burned and unburned areas within sites; with negative associations between burned areas and some key indicator species including Drosera rotundifolia, Eriophorum vaginatum, Empetrum nigrum, Narthecium ossifragum and Trichophorum germanicum. We did not find any evidence of significant interactions between burning and habitat, suggesting that wildfires had similar impacts on each species regardless of the habitat in which they occurred.
Conclusions - This study differs from other UK studies in that it examines impacts of wildfires at sites that have not been previously intensively managed by burning. In particular, we highlight potential impacts on N. ossifragum and D. rotundifolia, which are key components of the upland flora and, to our knowledge, were not present in previous UK studies.
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Congestion control in wireless networks is an important and open issue. Previous research has proven the poor performance of the Transport Control Protocol (TCP) in such networks. The factors that contribute to the poor performance of TCP in wireless environments concern its unsuitability to identify/detect and react properly to network events, its TCP window based ow control algorithm that is not suitable for the wireless channel, and the congestion collapse due to mobility. New rate based mechanisms have been proposed to mitigate TCP performance in wired and wireless networks. However, these mechanisms also present poor performance, as they lack of suitable bandwidth estimation techniques for multi-hop wireless networks. It is thus important to improve congestion control performance in wireless networks, incorporating components that are suitable for wireless environments. A congestion control scheme which provides an e - cient and fair sharing of the underlying network capacity and available bandwidth among multiple competing applications is crucial to the definition of new e cient and fair congestion control schemes on wireless multi-hop networks. The Thesis is divided in three parts. First, we present a performance evaluation study of several congestion control protocols against TCP, in wireless mesh and ad-hoc networks. The obtained results show that rate based congestion control protocols need an eficient and accurate underlying available bandwidth estimation technique. The second part of the Thesis presents a new link capacity and available bandwidth estimation mechanism denoted as rt-Winf (real time wireless inference). The estimation is performed in real-time and without the need to intrusively inject packets in the network. Simulation results show that rt-Winf obtains the available bandwidth and capacity estimation with accuracy and without introducing overhead trafic in the network. The third part of the Thesis proposes the development of new congestion control mechanisms to address the congestion control problems of wireless networks. These congestion control mechanisms use cross layer information, obtained by rt-Winf, to accurately and eficiently estimate the available bandwidth and the path capacity over a wireless network path. Evaluation of these new proposed mechanisms, through ns-2 simulations, shows that the cooperation between rt-Winf and the congestion control algorithms is able to significantly increase congestion control eficiency and network performance.
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Salt marshes are highly productive intertidal habitats that serve as nursery grounds for many commercially and economically important species. Because of their location and physical and biological characteristics, salt marshes are considered to be particularly vulnerable to anthropogenic inputs of oil hydrocarbons. Sediment contamination with oil is especially dangerous for salt marsh vegetation, since low molecular weight aromatic hydrocarbons can affect plants at all stages of development. However, the use of vegetation for bioremediation (phytoremediation), by removal or sequestration of contaminants, has been intensively studied. Phytoremediation is an efficient, inexpensive and environmental friendly approach for the removal of aromatic hydrocarbons, through direct incorporation by the plant and by the intervention of degrading microbial populations in the rhizosphere (microbe-assisted phytoremediation). Rhizosphere microbial communities are enriched in important catabolic genotypes for degradation of oil hydrocarbons (OH) which may have a potential for detoxification of the sediment surrounding the roots. In addition, since rhizosphere bacterial populations may also internalize into plant tissues (endophytes), rhizocompetent AH degrading populations may be important for in planta AH degradation and detoxification. The present study involved field work and microcosms experiments aiming the characterization of relevant plant-microbe interactions in oilimpacted salt marshes and the understanding of the effect of rhizosphere and endosphere bacteria in the role of salt marsh plants as potential phytoremediation agents. In the field approach, molecular tools were used to assess how plant species- and OH pollution affect sediment bacterial composition [bulk sediment and sediment surrounding the roots (rhizosphere) of Halimione portulacoides and Sarcocornia perennis subsp. perennis] in a temperate estuary (Ria de Aveiro, Portugal) chronically exposed to OH pollution. In addition, the 16S rRNA gene sequences retrieved in this study were used to generate in silico metagenomes and to evaluate the distribution of potential bacterial traits in different microhabitats. Moreover, a combination of culture-dependent and -independent approaches was used to investigate the effect of oil hydrocarbons contamination on the structure and function of endophytic bacterial communities of salt marsh plants.Root systems of H. portulacoides and S. perennis subsp. perennis appear to be able to exert a strong influence on bacterial composition and in silico metagenome analysis showed enrichment of genes involved in the process of polycyclic aromatic hydrocarbon (PAH) degradation in the rhizosphere of halophyte plants. The culturable fraction of endophytic degraders was essentially closely related to known OH-degrading Pseudomonas species and endophytic communities revealed sitespecific effects related to the level of OH contamination in the sediment. In order to determine the effects of oil contamination on plant condition and on the responses in terms of structure and function of the bacterial community associated with plant roots (rhizosphere, endosphere), a microcosms approach was set up. The salt marsh plant Halimione portulacoides was inoculated with a previous isolated Pseudomonas sp. endophytic degrader and the 2-methylnaphthalene was used as model PAH contaminant. The results showed that H. portulacoides health and growth were not affected by the contamination with the tested concentration. Moreover, the decrease of 2-methylnaphthalene at the end of experiment, can suggest that H. portulacoides can be considered as a potential plant for future uses in phytoremedition approaches of contaminated salt marsh. The acceleration of hydrocarbon degradation by inoculation of the plants with the hydrocarbon-degrading Pseudomonas sp. could not, however, be demonstrated, although the effects of inoculation on the structure of the endophytic community observed at the end of the experiment indicate that the strain may be an efficient colonizer of H. portulacoides roots. The results obtained in this work suggest that H. portulacoides tolerates moderate concentrations of 2-methylnaphthalene and can be regarded as a promising agent for phytoremedition approaches in salt marshes contaminated with oil hydrocarbons. Plant/microbe interactions may have an important role in the degradation process, as plants support a diverse endophytic bacterial community, enriched in genetic factors (genes and plasmids) for hydrocarbon degradation.
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Background In recent years, an abstinence-focused, ‘recovery’ agenda has emerged in UK drug policy, largely in response to the perception that many opioid users had been ‘parked indefinitely’ on Opioid Substitution Therapy (OST). The introduction of ten pilot ‘Drug Recovery Wings’ (DRWs) in 2011 represents the application of this recovery agenda to prisons. This paper describes the DRWs’ operational models, the place of opiate dependent prisoners within them, and the challenges of delivering ‘recovery’ in prison. Methods In 2013, the implementation and operational models of all ten pilot DRWs were rapidly assessed. Up to three days were spent in each DRW, undertaking semi-structured interviews with a sample of 94 DRW staff and 102 DRW residents. Interviews were fully transcribed, and coded using grounded theory. Findings from the nine adult prisons are presented here. Results Four types of DRW were identified, distinguished by their size and selection criteria. Strikingly, no mid- or large-sized units regularly supported OST recipients through detoxification. Type A were large units whose residents were mostly on OST with long criminal records and few social or personal resources. Detoxification was rare, and medication reduction slow. Type B's mid-sized DRW was developed as a psychosocial support service for OST clients seeking detoxification. However, staff struggled to find such prisoners, and detoxification again proved rare. Type C DRWs focused on abstinence from all drugs, including OST. Though OST clients were not intentionally excluded, very few applied to these wings. Only Type D DRWs, offering intensive treatment on very small wings, regularly recruited OST recipients into abstinence-focused interventions. Conclusion Prison units wishing to support OST recipients in making greater progress towards abstinence may need to be small, intensive and take a stepped approach based on preparatory motivational work and extensive preparation for release. However, concerns about post-release deaths will remain.
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Dissertação de Mestrado, Engenharia Biológica, Faculdade de Engenharia de Recursos Naturais, Universidade do Algarve, 2008
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London has traditionally exported most of its waste to former mineral workings in surrounding counties for landfill. Many of these sites are being filled and opportunities for new sites are limited. Virtually all waste reprocessing and recycling facilities, with the exception of textile sorting and some facilities for glass and organic waste composting, are outside London. The Mayor of London's Vision for Waste in London is that by 2020, municipal waste should not compromise London’s future as a sustainable city. This will involve managing waste better, so that its impact on the local and global environment and on London communities, economy and health is minimised. The majority of waste and recyclable materials in London are currently collected and transported for recovery, disposal or reprocessing by road in large vehicles. Environmental costs include, adding to congestion, noise, energy usage, air pollution, and accidents. The Mayor is keen to increase recycling and reuse of waste materials in London, and to ensure that as more of London's waste is diverted away from landfill sites to recycling facilities. Several projects and initiatives have been established and these are reviewed in the paper.
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Thesis (Master's)--University of Washington, 2015-12
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Benzodiazepines are group of drugs used mainly as sedatives, hypnotics, muscle relaxants, and anti-epileptics. Tapering off benzodiazepines is, for some users, a painful, traumatic, and protracted process. In this article, I use an autoethnographic approach, adopting the metaphor of water, to examine heuristically my experience of iatrogenic illness and recovery. I draw on personal journals and blog entries and former users’ narratives to consider the particular form of biographical disruption associated with benzodiazepines and the processes involved in identity reconstruction. I emphasize the role of the online community in providing benzodiazepine users such as myself with a co-cultural community through which to share a voice and make sense of our experiences. I explain how the success stories of former users provided me with the hope that I, the “medical victim,” could become the “victor” and in the process construct a new life and fresh identity.
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This paper assesses whether two sustainability policies currently in effect in London, a congestion charge zone and a low emission zone, have affected freight operations and reduced vehicle kilometers travelled. It investigates responses by freight operators, including re-timing, re-routing, or reducing the number of trips, or replacing vehicles. Freight traffic trends from 1994 to 2012 were identified using road traffic estimates, cordon counts, and vehicle speed data and supplemented by interviews with freight industry experts and operators. Findings indicate that freight traffic increased throughout London during this timeframe, but declined in the central boroughs partly within the congestion charge zone. The congestion charge may have time-shifted some light goods trips, but most freight trips face a variety of constraints on operators’ delivery window. No evidence was found of re-routing of freight traffic or avoidance traffic around the charged zone. The low emission zone spurred higher levels of operational change than the congestion charge zone, and it was effective at spurring freight vehicle replacement. The paper also discusses freight operators’ perceptions of these policies and how they could be improved.
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We present a method for recovering facial shape using an image of a face and a reference model. The zenith angle of the surface normal is recovered directly from the intensities of the image. The azimuth angle of the reference model is then combined with the calculated zenith angle in order to get a new field of surface normals. After integration of the needle map, the recovered surface has the effect of mapped facial features over the reference model. Experiments demonstrate that for the lambertian case, surface recovery is achieved with high accuracy. For non-Lambertian cases, experiments suggest potential for face recognition applications.
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Understanding the impact of training sessions on the immune response is crucial for the adequate periodization of training, to prevent both a negative influence on health and a performance impairment of the athlete. This study evaluated acute systemic immune cell changes in response to an actual swimming session, during a 24-h recovery period, controlling for sex, menstrual cycle phases, maturity, and age group. Competitive swimmers (30 females, 15 ± 1.3 years old; and 35 males, 16.5 ± 2.1 years old) performed a high-intensity training session. Blood samples were collected before, immediately after, 2 h after, and 24 h after exercise. Standard procedures for the assessment of leukogram by automated counting (Coulter LH 750, Beckman) and lymphocytes subsets by flow cytometry (FACS Calibur BD, Biosciences) were used. Subjects were grouped according to competitive age groups and pubertal Tanner stages. Menstrual cycle phase was monitored. The training session induced neutrophilia, lymphopenia, and a low eosinophil count, lasting for at least 2 h, independent of sex and maturity. At 24 h postexercise, the acquired immunity of juniors (15-17 years old), expressed by total lymphocytes and total T lymphocytes (CD3+), was not fully recovered. This should be accounted for when planning a weekly training program. The observed lymphopenia suggests a lower immune surveillance at the end of the session that may depress the immunity of athletes, highlighting the need for extra care when athletes are exposed to aggressive environmental agents such as swimming pools
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In a liberalized electricity market, the Transmission System Operator (TSO) plays a crucial role in power system operation. Among many other tasks, TSO detects congestion situations and allocates the payments of electricity transmission. This paper presents a software tool for congestion management and transmission price determination in electricity markets. The congestion management is based on a reformulated Optimal Power Flow (OPF), whose main goal is to obtain a feasible solution for the re-dispatch minimizing the changes in the dispatch proposed by the market operator. The transmission price computation considers the physical impact caused by the market agents in the transmission network. The final tariff includes existing system costs and also costs due to the initial congestion situation and losses costs. The paper includes a case study for the IEEE 30 bus power system.