246 research outputs found
Assessing the cumulative environmental effects of marine renewable energy developments: establishing common ground
Assessing and managing the cumulative impacts of human activities on the environment remains a major challenge to sustainable development. This challenge is highlighted by the worldwide expansion of marine renewable energy developments (MREDs) in areas already subject to multiple activities and climate change. Cumulative effects assessments in theory provide decision makers with adequate information about how the environment will respond to the incremental effects of licensed activities and are a legal requirement in many nations. In practise, however, such assessments are beset by uncertainties resulting in substantial delays during the licensing process that reduce MRED investor confidence and limit progress towards meeting climate change targets. In light of these targets and ambitions to manage the marine environment sustainably, reducing the uncertainty surrounding MRED effects and cumulative effects assessment are timely and vital. This review investigates the origins and evolution of cumulative effects assessment to identify why the multitude of approaches and pertinent research have emerged, and discusses key considerations and challenges relevant to assessing the cumulative effects of MREDs and other activities on ecosystems. The review recommends a shift away from the current reliance on disparate environmental impact assessments and limited strategic environmental assessments, and a move towards establishing a common system of coordinated data and research relative to ecologically meaningful areas, focussed on the needs of decision makers tasked with protecting and conserving marine ecosystems and services
Targeted Disruption of the Neurotensin Receptor Gene
The primary aim of the work presented in this thesis was to investigate the neurotensin transmission system of the mouse CNS by employing a reverse genetic approach. The neurotensin peptide and receptor distribution within the CNS has been extensively mapped, implicating a role of neurotensin in many brain functions but little is known of the exact functional relationship of neurotensin transmission with respect to other neuronal pathways. However, increasing biochemical, electrophysiological and neuropharmacological data have highlighted a neuromodulatory role of neurotensin over the dopaminergic mesolimbic and nigrostriatal pathways. These pathways are involved in the regulation of movement and motivational behaviour, which are believed to underlie the mechanism of reward reinforcement for such drugs as cocaine, as well as being important to the pathophysiology of schizophrenia. Two gene targeting approaches were undertaken to create a null mutation of the neurotensin high affinity receptor. The first strategy was based on the 'Hit and Run' procedure of Hasty et al., 1992a. An integrative vector was designed based on a 2.8 kb BamHI DNA fragment of the neurotensin receptor gene subcloned from a lambda EMBL3 Balb/c mouse genomic library. Sequence analysis of the BamHI fragment revealed a large open reading frame encoding sequence encompassing the first four transmembrane domains of the receptor. Subsequent vector construction involved the introduction of a mutagenic linker which introduced a stop codon within the sequence encoding the first transmembrane domain of the receptor. PCR analysis of ES cell clones transfected with the integrative vector, (pKLF), indicated the targeted integration of pKLF at the neurotensin receptor gene locus. However, selection of these ES clones for the desired reversion event did not result in the identification of any ES cell clones containing the linker mutation within the NTR gene. Re-evaluation of the 'Hit and Run' technique, in light of the increased understanding of the factors governing gene targeting in ES cells, led to a change in approach. The second strategy utilised a replacement type vector in combination with the 'positive negative selection' regime, (Thomas and Capecchi, 1987), to target the neurotensin receptor gene. The replacement vector used was constructed from a 5' 9.2 kb EcoRI fragment of the neurotensin receptor gene subcloned from the lambda Dash 129J mouse genomic library. The targeting construct introduced a deletion and a disrupting neomycin cassette into the receptor gene within the sequence encoding the fourth transmembrane domain. This targeting construct was successfully used to target a number of ES cell lines; E14, Rl, CGR8 and CGR8.8. Of the 4 targeted Rl ES sublines, 2 produced weakly chimaeric mice, (10-15% ES cell derived). No germline transmission of the null NTR allele was obtained from repeated matings of these chimaeric mice. A targeted CGR8 ES cell subline was used to generate 3 highly chimaeric male mice, (80-90% ES cell derived). However these mice were apparently sterile, with no progeny being produced from repeated matings. Two other targeted sublines were produced from the CGR8.8 ES cell line, and are to be tested for germline transmission. In addition, an in situ hybridisation analysis of the neurotensin receptor expression within the developing mouse embryo, revealed specific localisation of the probe to an unidentified structure of the developing forebrain
Obligations and aspirations: A critical evaluation of offshore wind farm cumulative impact assessments
Proponents of marine renewable energy worldwide highlight that regulatory and consenting procedures are a significant barrier to the upscaling of infrastructure required to transform the energy generation sector. Uncertainties about the cumulative effects of marine renewable energy developments cause substantial delays during the consenting process, which are exacerbated by the lack of clarity about how to assess cumulative effects. These obstacles have contributed to perceptions that this essential emerging industry receives disproportionate scrutiny relative to established maritime activities. However, alongside legislated targets to reduce carbon emissions, there are legal obligations to protect, maintain and improve the condition of the marine environment. As the imperative to halt the decline in the condition of the environment increases, so expectations of cumulative impact assessments grow and the risk of consenting delays persists. To investigate how robust current cumulative impact assessment practise is, a novel evaluation framework was developed and applied to Environmental Statements of the world's largest offshore wind farms, currently in United Kingdom waters. The framework was designed to evaluate cumulative impact assessments relative to the information needs of decision-makers tasked with managing cumulative effects. We found that current practise does not meet those needs, that there is dissonance between science and practise, and problematic variability between assessments was observed. Straightforward recommendations for improved practise are provided, which if implemented may ease the perceived regulatory burden by clarifying practise. We also highlight additional steps that could enable project-led cumulative impact assessments to better support regional marine management. The results and recommendations will be of interest to countries worldwide where marine renewable energy is emerging alongside ecosystem-approach and marine spatial planning aspirations
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Genetic studies of reproductive and biochemical traits in turkeys (Meleagris gallopavo) divergently selected for semen ejaculate volume
The genetic control of changes in unselected traits of
Wrolstad Medium White turkeys divergently selected for
semen ejaculate volumes (SEV) for 16 generations (G) was
studied. Genetic parameters were estimated in G 10 to 14
for embryonic mortality (EM), the incidence of pipped eggs,
and for total plasma cholesterol (PC) and high density
lipoprotein cholesterol (HDLC) in 16-week old birds of G
15. An attempt at determining enzyme polymorphisms in the
two lines was performed in G 16. A multivariate discriminant
analysis procedure was established in an attempt to
classify birds as low or high SEV based on fertility and
incubation records in G 10 and 12.
It was determined that a more reliable, yet flexible
method of estimation of variance components for
heritability of embryonic mortality in turkeys is a
likelihood procedure. The mean heritability estimates were
-.03 and .10 for embryonic mortality in the early (Days 1-
10) and late (Days 21-28), respectively. Estimates of
heritability for the incidence of pipped eggs were .21 and
.08 in the low and high lines respectively.
Since there were no line differences (P>.05) for PC
and HDLC, data was pooled from low and high SEV lines and
h² was computed to be -.03 and .26, respectively. Genetic
correlation among PC, HDLC, and 16 week body weight (BW)
varied from .05 between PC and HDLC, .13 PC and BW and -.34
HDLC and BW. No polymorphisms were observed for the enzymes
examined in the present study.
The discriminant function developed to categorize
birds as low or high volume semen producers, had a moderate
(.55) to high (.75) hit ratio for classification of birds
as low or high volume producers in G 10 and 12.
It was concluded that divergence in unselected traits,
embryonic mortality and the incidence of pipped eggs, in
the low and high SEV lines had a negligible additive
genetic control. Cholesterol, though a major intermediate
in the biosynthesis of steroid hormones, in turkeys at 16
weeks of age is not a suitable biochemical marker for SEV.
Although genetic control in turkeys appears to be
negligible for PC, there is a moderate and significant
hereditary influence on HDLC. With a misclassification rate
of .30-.40, fertility and incubation records, as
demonstrated here can be used to classify birds as low or
high volume semen producers
Flexible Timing Simulation of Multiple-Cache Configurations
Abstract As the gap between processor and memory speeds increases, cache performance becomes more critical to overall system performance. Behavioral cache simulation is typically used early in the design cycle of new processor/cache configurations to determine the performance of proposed cache configurations on target workloads. However, behavioral cache simulation does not account for the latency seen by each memory access. The Latency-Effects (LE) cache model presented in this paper accounts this nominal latency as well as the additional latencies due to trailing-edge effects, bus width considerations, port conflicts, and the number of outstanding accesses that a cache allows before it blocks. We also extend the LE cache model to handle the latency effects of moving data among multiple caches. mlcache, a new, easily configurable and extensible tool, has been built based on the extended LE model. We show the use of mlcache in estimating the performance of traditional and novel cache configurations, including odd/even, 2-level, Assist, Victim, and NTS caches. We also show how the LE cache timing model provides more useful, realistic performance estimates than other possible behavioral-level cache timing models. Keywords: cache timing simulation model evaluation Introduction Cache performance becomes ever more critical to overall system performance as the gap between processor and memory speed increases. The performance of a particular cache configuration depends not only on the miss ratio incurred during the execution of a particular workload but also on where in the program's execution the misses occur and the latency of each miss. However, useful timing simulation of caches is typically unavailable until late in the design stage. Using today's behavioral simulators, simple, traditional caches are evaluated early in the design cycle; however, novel cache designs are often not considered since they are difficult to model. The issue of providing more useful cache timing simulation analysis early in the design cycle has been addressed by the Latency-Effects (LE) cache model [Tam96], which incorporates latency-adding effects into a behavioral-level simulation, particularly trailing-edge effects, bus width considerations, the effects of port conflicts, and the number of outstanding accesses that a cache can handle before blocking. Existing methods of modifying behavioral cache simulators to incorporate timing effects include adjusting the total cycle count reported by a perfect cache simulation by adding an estimated number of cycles due to cache misses (the adjusted model) or assigning a nominal leading-edge penalty to each miss as it occurs (a model we will refer to as LEnominal). To illustrate the advantages of the LE cache model, we will compare the LE cache model's results to the results of using these other models. 1. This research was funded in part by a gift from IBM
Differences in level of confidence in diabetes care between different groups of trainees: the TOPDOC diabetes study
Background
There is an increasing prevalence of diabetes. Doctors in training, irrespective of specialty, will have patients with diabetes under their care. The aim of this further evaluation of the TOPDOC Diabetes Study data was to identify if there was any variation in confidence in managing diabetes depending on the geographical location of trainees and career aspirations.
Methods
An online national survey using a pre-validated questionnaire was administered to trainee doctors. A 4-point confidence rating scale was used to rate confidence in managing aspects of diabetes care and a 6-point scale used to quantify how often trainees would contribute to the management of patients with diabetes. Responses were grouped depending on which UK country trainees were based and their intended career choice.
Results
Trainees in Northern Ireland reported being less confident in IGT diagnosis, use of IV insulin and peri-operative management and were less likely to adjust oral treatment, contact specialist, educate lifestyle, and optimise treatment. Trainees in Scotland were less likely to contact a specialist, but more likely to educate on lifestyle, change insulin, and offer follow-up advice. In Northern Ireland, Undergraduate (UG) and Postgraduate (PG) training in diagnosis was felt less adequate, PG training in emergencies less adequate, and reporting of need for further training higher. Trainees in Wales felt UG training to be inadequate. In Scotland more trainees felt UG training in diagnosis and optimising treatment was inadequate. Physicians were more likely to report confidence in managing patients with diabetes and to engage in different aspects of diabetes care. Aspiring physicians were less likely to feel the need for more training in diabetes care; however a clear majority still felt they needed more training in all aspects of care.
Conclusions
Doctors in training have poor confidence levels dealing with diabetes related care issues. Although there is variability between different groups of trainees according to geographical location and career aspirations, this is a UK wide issue. There should be a UK wide standardised approach to improving training for junior doctors in diabetes care with local training guided by specific needs.</p
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Food Insecurity as a Barrier to Sustained Antiretroviral Therapy Adherence in Uganda
Background: Food insecurity is emerging as an important barrier to antiretroviral (ARV) adherence in sub-Saharan Africa and elsewhere, but little is known about the mechanisms through which food insecurity leads to ARV non-adherence and treatment interruptions. Methodology: We conducted in-depth, open-ended interviews with 47 individuals (30 women, 17 men) living with HIV/AIDS recruited from AIDS treatment programs in Mbarara and Kampala, Uganda to understand how food insecurity interferes with ARV therapy regimens. Interviews were transcribed, coded for key themes, and analyzed using grounded theory. Findings: Food insecurity was common and an important barrier to accessing medical care and ARV adherence. Five mechanisms emerged for how food insecurity can contribute to ARV non-adherence and treatment interruptions or to postponing ARV initiation: 1) ARVs increased appetite and led to intolerable hunger in the absence of food; 2) Side effects of ARVs were exacerbated in the absence of food; 3) Participants believed they should skip doses or not start on ARVs at all if they could not afford the added nutritional burden; 4) Competing demands between costs of food and medical expenses led people either to default from treatment, or to give up food and wages to get medications; 5) While working for food for long days in the fields, participants sometimes forgot medication doses. Despite these obstacles, many participants still reported high ARV adherence and exceptional motivation to continue therapy. Conclusions: While reports from sub-Saharan Africa show excellent adherence to ARVs, concerns remain that these successes are not sustainable in the presence of widespread poverty and food insecurity. We provide further evidence on how food insecurity can compromise sustained ARV therapy in a resource-limited setting. Addressing food insecurity as part of emerging ARV treatment programs is critical for their long-term success
Acute Effects of Vibrating Insoles on Dynamic Balance and Gait Quality in Individuals With Diabetic Peripheral Neuropathy: A Randomized Crossover Study
OBJECTIVE This study investigated the effects of vibrating insoles on dynamic balance and gait quality during level and stair walking and explored the influence of vibration type and frequency in individuals with diabetic peripheral neuropathy (DPN). RESEARCH DESIGN AND METHODS Twenty-two men with DPN were assessed for gait quality and postural and dynamic balance during walking and stair negotiation using a motion capture system and force plates across seven vibratory insole conditions (Vcs) versus a control (Ctrl) condition (insole without vibration). Vibration was applied during standing and walking tasks, and 15-min rest-stop periods without vibration were interposed between conditions. Repeated measures test conditions were randomized. The primary outcomes were gait speed and dynamic balance. RESULTS Gait speed during walking significantly improved in all Vcs compared with Ctrl (P < 0.005), with Vc2, Vc4, and Vc6 identified as the most effective. Gait speed increased (reflecting faster walking) during stair ascent and descent in Vc2 (Ctrl vs. Vc2 for ascent 0.447 ± 0.180 vs. 0.517 ± 0.127 m/s; P = 0.037 and descent 0.394 ± 0.170 vs. 0.487 ± 0.125 m/s; P = 0.016), Vc4 (Ctrl vs. Vc4 for ascent 0.447 ± 0.180 vs. 0.482 ± 0.197 m/s; P = 0.047 and descent 0.394 ± 0.170 vs. 0.438 ± 0.181 m/s; P = 0.017), and Vc6 (Ctrl vs. Vc6 for ascent 0.447 ± 0.180 vs. 0.506 ± 0.179 m/s; P = 0.043 and descent 0.394 ± 0.170 vs. 0.463 ± 0.159 m/s; P = 0.026). Postural balance improved during quiet standing with eyes closed in Vc2, Vc4, Vc6, and Vc7 (P < 0.005). CONCLUSIONS Vibrating insoles are an effective acute strategy for improving postural balance and gait quality during level walking and stair descent in individuals with DPN. These benefits are particularly evident when the entire plantar foot surface is stimulated
Sampling a Littoral Fish Assemblage: Comparison of Small-Mesh Fyke Netting and Boat Electrofishing
We compared small-mesh (4-mm) fyke netting and boat electrofishing for sampling a littoral fish assemblage in Muskegon Lake, Michigan. We hypothesized that fyke netting selects for small-bodied fishes and electrofishing selects for large-bodied fishes. Three sites were sampled during May (2004 and 2005), July (2005 only), and September (2004 and 2005). We found that the species composition of captured fish differed considerably between fyke netting and electrofishing based on nonmetric multidimensional scaling (NMDS). Species strongly associated with fyke netting (based on NMDS and relative abundance) included the brook silverside Labidesthes sicculus, banded killifish Fundulus diaphanus, round goby Neogobius melanostomus, mimic shiner Notropis volucellus, and bluntnose minnow Pimephales notatus, whereas species associated with electrofishing included the Chinook salmon Oncorhynchus tshawytscha, catostomids (Moxostoma spp. and Catostomus spp.), freshwater drum Aplodinotus grunniens, walleye Sander vitreus, gizzard shad Dorosoma cepedianum, and common carp Cyprinus carpio. The total length of fish captured by electrofishing was 12.8 cm (95% confidence interval ¼ 5.5– 17.2 cm) greater than that of fish captured by fyke netting. Size selectivity of the gears contributed to differences in species composition of the fish captured, supporting our initial hypothesis. Thus, small-mesh fyke nets and boat electrofishers provided complementary information on a littoral fish assemblage. Our results support use of multiple gear types in monitoring and research surveys of fish assemblages.
Copyright by the American Fisheries Society 2007, Originally published in the North American Journal of Fisheries Management 27: 825-831, 2007
Structuring cumulative effects assessments to support regional and local marine management and planning obligations
Cumulative effects assessments are a legal requirement in many jurisdictions and are key to informing marine policy. However, practice does not yet deliver fit-for-purpose assessments relative to sustainable development and environmental protection obligations. The complexity of cumulative effect questions, which are embedded in complex social-ecological systems, makes multiple, methodologically diverse assessments a necessity. Using the expansion of marine renewable energy developments in European Union waters as a case study, this paper explores how social-ecological systems thinking and cumulative effects assessment theory can combine to structure CEAs that better support the management and regulation of maritime activities at regional scales. A general perspective for cumulative effects assessment is proposed to remove ambiguity of intent and to orient assessments towards a common objective. Candidate principles for practice are presented for consideration. These principles are integrated into a stepped assessment approach that seeks to improve cumulative effects assessments of localised activities relative to the information needs of decision-makers implementing the ecosystem approach
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