831 research outputs found

    Internal Migration and Regional Population Dynamics in Europe: Czech Case Study

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    Report prepared for the Council of Europe (Directorate of Social and Economic Affairs, Population and Migration Division) and for European Commission (Directorate General V, Employment, Industrial Relations and Social Affairs, Unit E1, Analysis and Research on the Social Situation) Czech Republic has experienced, over the last decade, quite a balanced population system with low growth. This has changed recently and from 1994 we noted a decrease in population partially offset by international migration, for the time being mainly temporary labour circular movements. The decreasing trend may well continue due to future replacement in the reproductive ages of large female cohorts with much smaller cohorts, currently aged 0-15 years. Ales and Simek (1996) expect by the year 2020 a population decrease of at least 471 thousand (high variant). International migration will probably reduce to some extent the effect of negative natural increase. In terms of population dynamics the most important feature we have observed is slow but clear deconcentration of population from large cities to suburban areas. The main gains are observed in medium size towns and smaller communities at the expense of large cities and rural areas. However, the migration factor plays a lesser role than in the past. Net migration is low and migration effectiveness is very limited. The relationship between migration and other variables (population density, level of urbanisation) is rather weak. Unemployment has limited negative impacts on migration flows. No doubt, this may change when the serious restructuring of industry starts and unemployment increases - an almost certain scenario given the Czech Republic's willingness to join the European Union. The main enigma of the Czech migration system is its future dynamics. So far migration has been low, but with the development of the economy, including the housing market, improvement of telecommunication and increasing wealth of the society one may expect that migration trends would contribute much more to the regional population dynamics. The large units for which migration data were available in the Czech Republic reduce the number of inter-unit migrations, increase the number of intra-unit migrations, and in effect blur the picture of mobility, which anyway is quite low. Another factor, which made the analysis somewhat difficult is the mixture of signals sent to the economy by the Czech government. This mixture has confused professional economists, not to speak of ordinary people

    Fire and Forage: Variability in Elk Forage on a Landscape of Wildfire and Changing Fire Management

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    Forest management practices can modify ungulate nutritional resources through landscape-scale processes such as prescribed fire and wildfire. The resulting availability and distribution of nutritional resources can affect ungulate survival, reproduction, and distribution. Our primary goals were to evaluate how landscapes with varying post-fire successional stages influence elk summer nutritional resources and to quantify the variability of nutritional resources associated with varying fire histories and management practices during 1900–2015. Within 3 elk population ranges located in the Bitterroot Valley, Montana, we measured elk forage quality across a range of land cover types and fire histories and developed a landscape-scale forage quality model. Based on historical wildfire and prescribed fire data, we reconstructed decadal land cover models and used our forage models to predict fire-related variations in forage quality each decade within the elk summer ranges. Forage quality was predicted to decrease with successional stage. The area burned by wildfire increased 242–1,772% during 1990–2015 as compared to 1900–1990, resulting in firerelated variations of predicted nutritional resources. The area of highest forage quality varied, increasing 31.3–48.5% in 2 ranges and decreasing 2.4% in 1 range, from 1900–1990 to 1990–2015. These results highlight the important effect of wildfire on the distribution of ungulate nutritional resources and demonstrate that ungulate nutritional resources likely vary over time with variation in fire history and management practices

    Oral splints for patients with temporomandibular disorders or bruxism : a systematic review and economic evaluation

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    This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 7. See the NIHR Journals Library website for further project information.Peer reviewedPublisher PD

    Oral splints for temporomandibular disorder or bruxism : a systematic review

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    Funded by: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment Programme (Project number: 16/146/06). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.Peer reviewedPublisher PD

    Nanoscale Si fishbone structures for manipulating heat transport using phononic resonators for thermoelectric applications

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    Thermoelectric materials have the potential to convert waste heat into electricity, but their thermoelectric efficiency must be improved before they are effective and economically viable. One promising route to improving thermoelectric efficiency in thin-film thermoelectric materials is to reduce the material’s thermal conductivity through nanopatterning the surface. In this work nanoscale phononic resonators are introduced to the surface, and their potential to reduce thermal conductivity is explored via coupled experimental and theoretical techniques. Atomistic modelling is used to predict the dependence of the thermal conductivity on different design parameters and used to guide the design and fabrication of silicon fishbone nanostructures. The nanostructure design incorporates a variation on design parameters such as barb length, width and spacing along the shaft length to enable correlation with changes in thermal conductivity. The thermal characteristics of the nanostructures are investigated experimentally using the spatial resolution of scanning thermal microscopy to correlate changes in thermal conductivity with the changes in the structure parameters. The method developed uses a microheater to establish a temperature gradient along the structure which will be affected by any local variations in thermal conductivity. The impact on the thermal gradient and consequently on the tip temperature is modelled using finite element computer simulations. Experimental changes as small as 7.5% are shown to be detectable in this way. Despite the experimental technique being shown to be able to detect thermal changes far smaller than those predicted by the modelling, no modifications of the thermal conductivity are detected. It is concluded that in order to realise the effects of phononic resonators to reduce thermal conductivity, that much smaller structures with a greater ratio of resonator to shaft will be needed

    BET bromodomains regulate transforming growth factor-beta-induced proliferation and cytokine release in asthmatic airway smooth muscle

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    Airway smooth muscle (ASM) mass is increased in asthma, and ASM cells from patients with asthma are hyperproliferative and release more IL-6 and CXCL8. The BET (bromo- and extra-terminal) family of proteins (Brd2, Brd3, and Brd4) govern the assembly of histone acetylation-dependent chromatin complexes. We have examined whether they modulate proliferation and cytokine expression in asthmatic ASM cells by studying the effect of BET bromodomain mimics JQ1/SGCBD01 and I-BET762. ASM cells from healthy individuals and nonsevere and severe asthmatics were pretreated with JQ1/SGCBD01 and I-BET762 prior to stimulation with FCS and TGF-β. Proliferation was measured by BrdU incorporation. IL-6 and CXCL8 release was measured by ELISA, and mRNA expression was measured by quantitative RT-PCR. ChIP using a specific anti-Brd4 antibody and PCR primers directed against the transcriptional start site of IL-6 and CXCL8 gene promoters was performed. Neither JQ1/SGCBD01 nor I-BET762 had any effect on ASM cell viability. JQ1/SGCBD01 and I-BET762 inhibited FCS+TGF-β-induced ASM cell proliferation and IL-6 and CXCL8 release in healthy individuals (≥ 30 nm) and in nonsevere and severe asthma patients (≥100 nm), with the latter requiring higher concentrations of these mimics. JQ1/SGCBD01 reduced Brd4 binding to IL8 and IL6 promoters induced by FCS+TGF-β. Mimics of BET bromodomains inhibit aberrant ASM cell proliferation and inflammation with lesser efficiency in those from asthmatic patients. They may be effective in reducing airway remodeling in asthma

    Mitochondrial abnormalities in ageing macular photoreceptors

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    PURPOSE. To evaluate somatic mitochondrial (mt)DNA mutations in the macula during ageing. METHODS. Ten 30-m cryostat sections from the macula (foveal and perifoveal regions) and peripheral retina of 14 donors (aged 14 -94 years) were cut for cytochrome c oxidase cytochemistry. The photoreceptor layer was microdissected and DNA extracted for 4977-bp mtDNA (mtDNA 4977 ) quantification using PCR. Dual cytochemistry for cytochrome c oxidase and succinate dehydrogenase allowed the detection of cytochrome c oxidase-deficient cones. RESULTS. Findings showed a progressive accumulation of mtDNA 4977 from ages 14 to 94 years. From ages 14 to 60 years there was an increase from 0.006% to 0.25%, and from ages 60 to 94 years there was a steeper increase from 0.25% to 5.39%. Counts of cones in the dual-reacted preparations showed more cytochrome c oxidase-deficient cones in the foveal region than elsewhere. CONCLUSIONS. The results show that mitochondrial DNA deletions and cytochrome c oxidase-deficient cones accumulate in the ageing retina, particularly in the foveal region. These defects may contribute to the changes in macular function observed in ageing and age-related maculopathy. (Invest Ophthalmol Vis Sci. 2001;42:3016 -3022) A geing is associated with a decline in macular function, with small but significant changes in both visual acuity and contrast sensitivity evident in most elderly individuals. Morphologic changes accompanying this ageing process primarily involve the photoreceptors and the cells of the retinal pigment epithelium (RPE). This is manifested by atrophy and loss of both cell types, depigmentation and hyperpigmentation of the RPE, a progressive accumulation of lipofuscin, drusen formation, thickening of Bruch's membrane, and the appearance of basal laminar deposits

    Pathogenesis of Rhinitis

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    Rhinitis is a heterogeneous condition that has been associated with inflammatory responses as in allergic rhinitis but can also occur in the absence of inflammation such as in so-called ‘idiopathic’ (previously ‘vasomotor’) rhinitis. Allergic rhinitis affects approximately 1 in 4 of the population of westernised countries and is characterized by typical symptoms of nasal itching, sneezing, watery discharge and congestion. The intention of this review is to illustrate key concepts of the pathogenesis of rhinitis. Imbalance in innate and adaptive immunity together with environmental factors is likely to play major roles. In allergic rhinitis, initial allergen exposure and sensitization involves antigen presenting cells, T and B lymphocytes and results in the generation of allergen-specific T cells and allergen specific IgE antibodies. On re-exposure to relevant allergens crosslinking of IgE on mast cells results in the release of mediators of hypersensitivity such as histamine and immediate nasal symptoms. Within hours, there is an infiltration by inflammatory cells, particularly Th2 T lymphocytes, eosinophils and basophils into nasal mucosal tissue that results in the late-phase allergic response. Evidence for nasal priming and whether or not remodelling may be a feature of allergic rhinitis will be reviewed. The occurrence of so-called ‘local’ allergic rhinitis in the absence of systemic IgE will be discussed. Non-allergic (non-IgE mediated) rhinitis will be considered in the context of inflammatory and non-inflammatory disorders

    Indirect Potable Reuse: A Sustainable Water Supply Alternative

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    The growing scarcity of potable water supplies is among the most important issues facing many cities, in particular those using single sources of water that are climate dependent. Consequently, urban centers are looking to alternative sources of water supply that can supplement variable rainfall and meet the demands of population growth. A diversified portfolio of water sources is required to ensure public health, as well as social, economical and environmental sustainability. One of the options considered is the augmentation of drinking water supplies with advanced treated recycled water. This paper aims to provide a state of the art review of water recycling for drinking purposes with emphasis on membrane treatment processes. An overview of significant indirect potable reuse projects is presented followed by a description of the epidemiological and toxicological studies evaluating any potential human health impacts. Finally, a summary of key operational measures to protect human health and the areas that require further research are discussed
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