Unsteady effects during resistance tests on a ship model in a towing tank

It is known that there are oscillations in the wave resistance during the constantvelocity phase of a towing-tank resistance test on a ship model. In this work, the unsteady thin-ship resistance theory has been applied to this case. The results have been compared with experiment data obtained using a towing carriage the velocity history of which can be programmed. It is demonstrated here that generally excellent correlation exists between the theory and the experiments. In particular, one can predict the influence of Froude number, rate of acceleration, and type of smoothing of the acceleration on the characteristics of the oscillations. These characteristics include the amplitude, rate of decay, frequency, and phasing of the oscillations in the curve of wave resistance versus time

Tetrahydrobiopterin Supplementation Improves Endothelial Function But Does Not Alter Aortic Stiffness in Patients With Rheumatoid Arthritis.

BACKGROUND: Rheumatoid arthritis is a systemic inflammatory condition associated with increased cardiovascular risk that may be due to underlying endothelial dysfunction and subsequent aortic stiffening. We hypothesized that supplementation with tetrahydrobiopterin (BH4) would recouple endothelial nitric oxide synthase and thus improve endothelial function and consequently reduce aortic stiffness. METHODS AND RESULTS: We conducted 2 randomized, double-blinded, placebo-controlled crossover studies examining 2 separate regimens: an acute regimen, with a single dose of BH4 400 mg versus placebo (n=18), and a short-term regimen, composed of a 1-week treatment with BH4 400 mg once daily versus placebo (n=15). Flow-mediated dilatation and aortic pulse wave velocity were studied 4 times, before and after each treatment phase. Acute BH4 supplementation led to an improvement of flow-mediated dilatation, whereas placebo had no effect (mean±SD of effect difference 2.56±4.79%; P=0.03). Similarly, 1-week treatment with BH4 improved endothelial function, but there was no change with placebo (mean±SD of effect difference 3.50±5.05%; P=0.02). There was no change in aortic pulse wave velocity following acute or short-term BH4 supplementation or placebo (mean±SD of effect difference: acute 0.09±0.67 m/s, P=0.6; short-term 0.03±1.46 m/s, P=0.9). CONCLUSION: Both acute and short-term supplementation with oral BH4 improved endothelial function but not aortic stiffness. This result suggests that BH4 supplementation may be beneficial for patients with rheumatoid arthritis by improving endothelial dysfunction and potentially reducing risk of cardiovascular disease. There appears to be no causal relationship between endothelial function and aortic stiffness, suggesting that they occur in parallel, although they may share common risk factors such as inflammation.KMMP and IBW were funded by British Heart Foundation. IBW, JC and NS received funding from the Comprehensive Local Research Network and IBW and JC from the National Institute for Health Research: Cambridge Biomedical Research Centre.This is the final version of the article. It first appeared from Wiley Blackwell via http://dx.doi.org/10.1161/JAHA.115.00276

Building development and roads: implications for the distribution of stone curlews across the Brecks

Background: Substantial new housing and infrastructure development planned within England has the potential to conflict with the nature conservation interests of protected sites. The Breckland area of eastern England (the Brecks) is designated as a Special Protection Area for a number of bird species, including the stone curlew (for which it holds more than 60% of the UK total population). We explore the effect of buildings and roads on the spatial distribution of stone curlew nests across the Brecks in order to inform strategic development plans to avoid adverse effects on such European protected sites. Methodology: Using data across all years (and subsets of years) over the period 1988 – 2006 but restricted to habitat areas of arable land with suitable soils, we assessed nest density in relation to the distances to nearest settlements and to major roads. Measures of the local density of nearby buildings, roads and traffic levels were assessed using normal kernel distance-weighting functions. Quasi-Poisson generalised linear mixed models allowing for spatial auto-correlation were fitted. Results: Significantly lower densities of stone curlew nests were found at distances up to 1500m from settlements, and distances up to 1000m or more from major (trunk) roads. The best fitting models involved optimally distance-weighted variables for the extent of nearby buildings and the trunk road traffic levels. Significance : The results and predictions from this study of past data suggests there is cause for concern that future housing development and associated road infrastructure within the Breckland area could have negative impacts on the nesting stone curlew population. Given the strict legal protection afforded to the SPA the planning and conservation bodies have subsequently agreed precautionary restrictions on building development within the distances identified and used the modelling predictions to agree mitigation measures for proposed trunk road developments

Glucanase Inhibitor Protein (GIP)

Several key cellular events, such as adhesion to the host surface, penetration, and colonization of host tissue, take place during plant infection by oomycetes that can also manipulate biochemical and physiological processes in their host plants through a diverse array of virulence or avirulence molecules, known as effectors (Birch et al. 2006; Ellis et al. 2006; Kamoun 2007; Schornack et al. 2009). In susceptible plants, these effectors promote infection by suppressing defense responses, enhancing susceptibility, or inducing disease symptoms. In resistant plants, the products of the resistance genes are able to recognize the effectors, promoting an efective defense response known as hypersensitive response (HR) which restricts the pathogen to an area of scorched earth besides host cell death (Kamoun 2003; Kamoun 2007; Schornack et al. 2009). Phytophthora effectors that suppress host defense responses have be ...info:eu-repo/semantics/publishedVersio

Phytoestrogens

Collectively, plants contain several different families of natural products among which are compounds with weak estrogenic or antiestrogenic activity toward mammals. These compounds, termed phytoestrogens, include certain isoflavonoids, flavonoids, stilbenes, and lignans. The best-studied dietary phytoestrogens are the soy isoflavones and the flaxseed lignans. Their perceived health beneficial properties extend beyond hormone-dependent breast and prostate cancers and osteoporosis to include cognitive function, cardiovascular disease, immunity and inflammation, and reproduction and fertility. In the future, metabolic engineering of plants could generate novel and exquisitely controlled dietary sources with which to better assess the potential health beneficial effects of phytoestrogens

Effect of Biodiversity Changes in Disease Risk: Exploring Disease Emergence in a Plant-Virus System

The effect of biodiversity on the ability of parasites to infect their host and cause disease (i.e. disease risk) is a major question in pathology, which is central to understand the emergence of infectious diseases, and to develop strategies for their management. Two hypotheses, which can be considered as extremes of a continuum, relate biodiversity to disease risk: One states that biodiversity is positively correlated with disease risk (Amplification Effect), and the second predicts a negative correlation between biodiversity and disease risk (Dilution Effect). Which of them applies better to different host-parasite systems is still a source of debate, due to limited experimental or empirical data. This is especially the case for viral diseases of plants. To address this subject, we have monitored for three years the prevalence of several viruses, and virus-associated symptoms, in populations of wild pepper (chiltepin) under different levels of human management. For each population, we also measured the habitat species diversity, host plant genetic diversity and host plant density. Results indicate that disease and infection risk increased with the level of human management, which was associated with decreased species diversity and host genetic diversity, and with increased host plant density. Importantly, species diversity of the habitat was the primary predictor of disease risk for wild chiltepin populations. This changed in managed populations where host genetic diversity was the primary predictor. Host density was generally a poorer predictor of disease and infection risk. These results support the dilution effect hypothesis, and underline the relevance of different ecological factors in determining disease/infection risk in host plant populations under different levels of anthropic influence. These results are relevant for managing plant diseases and for establishing conservation policies for endangered plant species

The fitness of African malaria vectors in the presence and limitation of host behaviour

<p>Background Host responses are important sources of selection upon the host species range of ectoparasites and phytophagous insects. However little is known about the role of host responses in defining the host species range of malaria vectors. This study aimed to estimate the relative importance of host behaviour to the feeding success and fitness of African malaria vectors, and assess its ability to predict their known host species preferences in nature.</p> <p>Methods Paired evaluations of the feeding success and fitness of African vectors Anopheles arabiensis and Anopheles gambiae s.s in the presence and limitation of host behaviour were conducted in a semi-field system (SFS) at Ifakara Health Institute, Tanzania. In one set of trials, mosquitoes were released within the SFS and allowed to forage overnight on a host that was free to exhibit natural behaviour in response to insect biting. In the other, mosquitoes were allowed to feed directly on from the skin surface of immobile hosts. The feeding success and subsequent fitness of vectors under these conditions were investigated on 6 host types (humans, calves, chickens, cows, dogs and goats) to assess whether physical movements of preferred host species (cattle for An. arabiensis, humans for An. gambiae s.s.) were less effective at preventing mosquito bites than those of common alternatives.</p> <p>Results Anopheles arabiensis generally had greater feeding success when applied directly to host skin than when foraging on unrestricted hosts (in five of six host species). However, An. gambiae s.s obtained blood meals from free and restrained hosts with similar success from most host types (four out of six). Overall, the blood meal size, oviposition rate, fecundity and post-feeding survival of mosquito vectors were significantly higher after feeding on hosts free to exhibit behaviour, than those who were immobilized during feeding trials.</p> <p>Conclusions Allowing hosts to move freely during exposure to mosquitoes was associated with moderate reductions in mosquito feeding success, but no detrimental impact to the subsequent fitness of mosquitoes that were able to feed upon them. This suggests that physical defensive behaviours exhibited by common host species including humans do not impose substantial fitness costs on African malaria vectors.</p&gt

Does tenure matter for occupant experiences of low-energy housing?

International policy settings are looking toward low-energy and near zero-energy homes as a solution to address environmental impacts, particularly anthropogenic climate change. There is increasing research evaluating sus-tainable housing developments from a technical and occupant perspective. One of the key determinants of household energy use is tenure. However, there is limited research which has looked at if tenure impacts on how oc-cupants experience low-energy homes. This paper contributes to the litera-ture by exploring three low-energy housing developments and exploring the role of tenure in relation to how the households experience the dwellings. The case studies demonstrate that social housing tenants have frustrations with a lack of control over what they could, or could not, do to their low-energy dwellings, in comparison to owner-occupier housing

The courage to change: Patient perceptions of 12-Step fellowships

<p>Abstract</p> <p>Background</p> <p>From a health services perspective, peer-based resources merit special attention. Participation in self-help fellowships, like the Twelve Step Groups (TSGs), have been shown to improve outcomes of patients with substance use disorder (SUD) and they represent a valuable adjunct to the SUD treatment system. This study investigated the relationship between patient perceptions of TSGs and the intent to participate in TSGs after receiving detoxification treatment.</p> <p>Methods</p> <p>We included 139 patients that entered a detoxification unit (detox) in Kristiansand, Norway. We analyzed factors associated with the intention to participate in TSGs post-discharge with contingency tables and ordinal regression analysis.</p> <p>Results</p> <p>Forty-eight percent of patients had participated in TSGs before entering detox. Respondents saw more advantages than disadvantages in TSG participation, but only 40% of patients showed high intentions of participating in TSGs post-discharge. A high intention to participate in TSGs was most strongly correlated with the notion that participation in TSGs could instill the courage to change. In a multivariate analysis, the perception that TSGs were beneficial was the strongest factor related to a high intention of TSG participation after treatment.</p> <p>Conclusions</p> <p>Our findings increased the understanding of factors most likely to influence decisions to attend TSGs in SUD treatment contexts with uncommon TSG participation. Our results suggested that the majority of patients may be sufficiently influenced by highlighting the potential gains of TSG participation. Treatment programs that do not focus on self-help group attendance during and after treatment should consider implementing facilitative measures to enhance utilization of these fellowships.</p