908 research outputs found
A Distributed Transaction and Accounting Model for Digital Ecosystem Composed Services
This paper addresses two known issues for dynamically
composed services in digital ecosystems. The first
issue is that of efficient distributed transaction management.
The conventional view of transactions is unsuitable as the local
autonomy of the participants is vital for the involvement of
SMEs. The second issue is that of charging for such distributed
transactions, where there will often be dynamically created
services whose composition is not known in advance and might
involve parts of different transactions. The paper provides solutions
for both of these issues, which can be combined to provide
for a unified approach to transaction management and
accounting of dynamically composed services in digital ecosystems
Streptococcus suis contains multiple phase-variable methyltransferases that show a discrete lineage distribution
Streptococcus suis is a major pathogen of swine, responsible for a number of chronic and acute infections, and is also emerging as a major zoonotic pathogen, particularly in South-East Asia. Our study of a diverse population of S. suis shows that this organism contains both Type I and Type III phase-variable methyltransferases. In all previous examples, phase-variation of methyltransferases results in genome wide methylation differences, and results in differential regulation of multiple genes, a system known as the phasevarion (phase-variable regulon). We hypothesized that each variant in the Type I and Type III systems encoded a methyltransferase with a unique specificity, and could therefore control a distinct phasevarion, either by recombination-driven shuffling between different specificities (Type I) or by biphasic on-off switching via simple sequence repeats (Type III). Here, we present the identification of the target specificities for each Type III allelic variant from S. suis using single-molecule, real-time methylome analysis. We demonstrate phase-variation is occurring in both Type I and Type III methyltransferases, and show a distinct association between methyltransferase type and presence, and population clades. In addition, we show that the phase-variable Type I methyltransferase was likely acquired at the origin of a highly virulent zoonotic sub-population
Gad65 is recognized by t-cells, but not by antibodies from nod-mice
Since the 64kDa-protein glutamic acid decarboxylase (GAD) is one of the major autoantigens in T-cell mediated Type 1 diabetes, its relevance as a T-cell antigen needs to be clarified. After isolation of splenic T-cells from non-obese diabetic (NOD) mice, a useful model for human Type 1 diabetes, we found that these T-cells proliferate spontaneously when incubated with human GAD65, but only marginally after incubation with GAD67, both recombinated in the baculovirus system. No effect was observed with non-diabetic NOD mice or with T-cells from H-2 identical NON-NOD-H-2g7 control mice. It has been published previously that NOD mice develop autoantibodies against a 64kDa protein detected with mouse beta cells. In immunoprecipitation experiments with sera from the same NOD mice and 33S-methionine-labelled GAD, no autoantibody binding could be detected. We conclude firstly that GAD65 is an important T-cell antigen which is relevant early in the development of Type 1 diabetes and secondly that there is an antigenic epitope in the human GAD65 molecule recognized by NOD T-cells, but not by NOD autoantibodies precipitating conformational epitopes. Our results therefore provide further evidence that GAD65 is a T-cell antigen in NOD mice, being possibly also involved in very early processes leading to the development of human Type 1 diabetes
Climate warming, marine protected areas and the ocean-scale integrity of coral reef ecosystems
Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution
of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the
associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of local
management in conserving coral reefs in the context of global climate change. Such information is important, as coral reef
fish assemblages are the most species dense vertebrate communities on earth, contributing critical ecosystem functions
and providing crucial ecosystem services to human societies in tropical countries. Our assessment of the impacts of the
1998 mass bleaching event on coral cover, reef structural complexity, and reef associated fishes spans 7 countries, 66 sites
and 26 degrees of latitude in the Indian Ocean. Using Bayesian meta-analysis we show that changes in the size structure,
diversity and trophic composition of the reef fish community have followed coral declines. Although the ocean scale
integrity of these coral reef ecosystems has been lost, it is positive to see the effects are spatially variable at multiple scales,
with impacts and vulnerability affected by geography but not management regime. Existing no-take marine protected areas
still support high biomass of fish, however they had no positive affect on the ecosystem response to large-scale disturbance.
This suggests a need for future conservation and management efforts to identify and protect regional refugia, which should
be integrated into existing management frameworks and combined with policies to improve system-wide resilience to
climate variation and change
Hydrothermal Growth and Application of ZnO Nanowire Films with ZnO and TiO2Buffer Layers in Dye-Sensitized Solar Cells
This paper reports the effects of the seed layers prepared by spin-coating and dip-coating methods on the morphology and density of ZnO nanowire arrays, thus on the performance of ZnO nanowire-based dye-sensitized solar cells (DSSCs). The nanowire films with the thick ZnO buffer layer (~0.8–1 μm thick) can improve the open circuit voltage of the DSSCs through suppressing carrier recombination, however, and cause the decrease of dye loading absorbed on ZnO nanowires. In order to further investigate the effect of TiO2buffer layer on the performance of ZnO nanowire-based DSSCs, compared with the ZnO nanowire-based DSSCs without a compact TiO2buffer layer, the photovoltaic conversion efficiency and open circuit voltage of the ZnO DSSCs with the compact TiO2layer (~50 nm thick) were improved by 3.9–12.5 and 2.4–41.7%, respectively. This can be attributed to the introduction of the compact TiO2layer prepared by sputtering method, which effectively suppressed carrier recombination occurring across both the film–electrolyte interface and the substrate–electrolyte interface
Recovery of a temperate reef assemblage in a marine protected area following the exclusion of towed demersal fishing.
Marine Protected Areas MPA have been widely used over the last 2 decades to address human impacts on marine habitats within an ecosystem management context. Few studies have quantified recovery of temperate rocky reef communities following the cessation of scallop dredging or demersal trawling. This is critical information for the future management of these habitats to contribute towards conservation and fisheries targets. The Lyme Bay MPA, in south west UK, has excluded towed demersal fishing gear from 206 km(2) of sensitive reef habitat using a Statutory Instrument since July 2008. To assess benthic recovery in this MPA we used a flying video array to survey macro epi-benthos annually from 2008 to 2011. 4 treatments (the New Closure, previously voluntarily Closed Controls and Near or Far Open to fishing Controls) were sampled to test a recovery hypothesis that was defined as 'the New Closure becoming more similar to the Closed Controls and less similar to the Open Controls'. Following the cessation of towed demersal fishing, within three years positive responses were observed for species richness, total abundance, assemblage composition and seven of 13 indicator taxa. Definitive evidence of recovery was noted for species richness and three of the indicator taxa (Pentapora fascialis, Phallusia mammillata and Pecten maximus). While it is hoped that MPAs, which exclude anthropogenic disturbance, will allow functional restoration of goods and services provided by benthic communities, it is an unknown for temperate reef systems. Establishing the likely timescales for restoration is key to future marine management. We demonstrate the early stages of successful recruitment and link these to the potential wider ecosystem benefits including those to commercial fisheries
High apex predator biomass on remote Pacific islands
Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Coral Reefs 26 (2007): 47-51, doi:10.1007/s00338-006-0158-x.On coral reefs in Palmyra—a central Pacific atoll with limited fishing
pressure—total fish biomass is 428 and 299% greater than on reefs in nearby
Christmas and Fanning Islands. Large apex predators –groupers, sharks, snappers, and
jacks larger than 50 cm in length- account for 56% of total fish biomass in Palmyra on
average, but only 7% and 3% on Christmas and Fanning. These biomass proportions
are remarkably similar to those previously reported for the remote and uninhabited
Northwest Hawaiian Islands (NWHI) and densely populated Main Hawaiian Islands
(MHI), although Palmyra’s reefs are dominated in biomass by sharks (44% of the
total), whereas the NWHI by jacks (39%). Herbivorous fish biomass was also greater
on Palmyra than on Christmas and Fanning (343% and 207%, respectively). These
results and previous findings indicate that remote, uninhabited islands support high
levels of consumers, and highlight the importance of healthy coral reef ecosystems as
reference points for assessment of human impacts and establishment of restoration
goals
Abscess Formation Following Spilled Gallstones During Laparoscopic Cholecystectomy
A review of the English literature concerning spilled gallstones during laparoscopic cholecystectomy is compared with one institution's experience of four cases during 1,726 laparoscopic cholecystectomies performed over a four-year period. Strategies regarding management and treatment are discussed
Designing clinical trials for assessing the effects of cognitive training and physical activity interventions on cognitive outcomes: The Seniors Health and Activity Research Program Pilot (SHARP-P) Study, a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>The efficacy of non-pharmacological intervention approaches such as physical activity, strength, and cognitive training for improving brain health has not been established. Before definitive trials are mounted, important design questions on participation/adherence, training and interventions effects must be answered to more fully inform a full-scale trial.</p> <p>Methods</p> <p>SHARP-P was a single-blinded randomized controlled pilot trial of a 4-month physical activity training intervention (PA) and/or cognitive training intervention (CT) in a 2 × 2 factorial design with a health education control condition in 73 community-dwelling persons, aged 70-85 years, who were at risk for cognitive decline but did not have mild cognitive impairment.</p> <p>Results</p> <p>Intervention attendance rates were higher in the CT and PACT groups: CT: 96%, PA: 76%, PACT: 90% (p=0.004), the interventions produced marked changes in cognitive and physical performance measures (p≤0.05), and retention rates exceeded 90%. There were no statistically significant differences in 4-month changes in composite scores of cognitive, executive, and episodic memory function among arms. Four-month improvements in the composite measure increased with age among participants assigned to physical activity training but decreased with age for other participants (intervention*age interaction p = 0.01). Depending on the choice of outcome, two-armed full-scale trials may require fewer than 1,000 participants (continuous outcome) or 2,000 participants (categorical outcome).</p> <p>Conclusions</p> <p>Good levels of participation, adherence, and retention appear to be achievable for participants through age 85 years. Care should be taken to ensure that an attention control condition does not attenuate intervention effects. Depending on the choice of outcome measures, the necessary sample sizes to conduct four-year trials appear to be feasible.</p> <p>Trial Registration</p> <p>Clinicaltrials.gov Identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00688155">NCT00688155</a></p
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