900 resultados para Low-impact camping.
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From humble beginnings less than twenty years ago, the economic relationship between Canada and the Chinese has flourished so that China is now Canada’s second most important trading partner after the United States. The Chinese demand for Canada’s exports, in particular in the natural resource sectors, has been a clear win for Canada, especially during the recent Great Recession where demand from other countries dropped sharply. But other aspects of the relationship have led to suggestions of costs. Canada’s large trade deficit with China at least looks superficially as a drag on the Canadian economy. It has been suggested the greater exposure to a low cost producer has displaced Canadian production and jobs and lowered wages. We find that each argument for costs to the relationship ignores important factors. On balance we conclude the relationship has been good for Canada, and it could be even better in the future.
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The endothelium is the inner most layer of cells that lines all arteries. A primary function of endothelial cells is to regulate responses to increased blood flow and the resulting frictional forces or shear stress by producing factors such as nitric oxide that mediate arterial dilation (flow mediated dilation (FMD)). Menstrual cycle variations in estrogen (E2) have been shown to influence brachial artery (BA) FMD in response to transient increases in shear stress brought about by the release of a brief forearm occlusion (reactive hyperemia (RH)). FMD can also be assessed in response to a sustained shear stress stimulus such as that created with handgrip exercise (HGEX), and studies have shown that RH- and HGEX stimulated FMD provide unique information regarding endothelial function. However, the impact of menstrual phase on HGEX-FMD is unknown. Therefore, the purpose of this study was to determine the impact of cyclical changes in E2 levels on HGEX-FMD over two discrete phases of the menstrual cycle. FMD was assessed via ultrasound. 12 subjects (21 ± 2yrs) completed two experimental visits: (1) low estrogen phase (early follicular) and (2) High estrogen phase (late follicular). In each visit both RH- and HGEX-FMD (6 min handgrip exercise) were assessed. Results are mean ± SD. E2 increased from the low to the high estrogen phase of the menstrual cycle (low: 34 ± 8, high: 161 ± 113pg/mL, p = 0.004). There was no change in mean FMD between phases (RH-FMD: 7.7 ± 4.3% vs. 6.4 ± 3.1%, p = 0.139; HGEX-FMD: 4.8 ± 2.8% vs. 4.8 ± 2.3%, p = 0.979). The observation that both RH- and HGEX-FMD did not differ between phases indicates that menstrual cycle fluctuations in estrogen may not universally impact endothelial function in young, healthy premenopausal women. Further research is needed to improve our understanding of the mechanisms that underlie variability in the impact of menstrual phase on both transient and sustained FMD responses.
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Nano-scale touch screen thin film have not been thoroughly investigated in terms of dynamic impact analysis under various strain rates. This research is focused on two different thin films, Zinc Oxide (ZnO) film and Indium Tin Oxide (ITO) film, deposited on Polyethylene Terephthalate (PET) substrate for the standard touch screen panels. Dynamic Mechanical Analysis (DMA) was performed on the ZnO film coated PET substrates. Nano-impact (fatigue) testing was performed on ITO film coated PET substrates. Other analysis includes hardness and the elastic modulus measurements, atomic force microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR) and the Scanning Electron Microscopy (SEM) of the film surface.
Ten delta of DMA is described as the ratio of loss modulus (viscous properties) and storage modulus (elastic properties) of the material and its peak against time identifies the glass transition temperature (Tg). Thus, in essence the Tg recognizes changes from glassy to rubber state of the material and for our sample ZnO film, Tg was found as 388.3 K. The DMA results also showed that the Ten delta curve for Tg increases monotonically in the viscoelastic state (before Tg) and decreases sharply in the rubber state (after Tg) until recrystallization of ZnO takes place. This led to an interpretation that enhanced ductility can be achieved by negating the strength of the material.
For the nano-impact testing using the ITO coated PET, the damage started with the crack initiation and propagation. The interpretation of the nano-impact results depended on the characteristics of the loading history. Under the nano-impact loading, the surface structure of ITO film suffered from several forms of failure damages that range from deformation to catastrophic failures. It is concluded that in such type of application, the films should have low residual stress to prevent deformation, good adhesive strength, durable and good resistance to wear.
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Hemizygous deletion of 17p (del(17p)) has been identified as a variable associated with poor prognosis in myeloma, although its impact in the context of thalidomide therapy is not well described. The clinical outcome of 85 myeloma patients with del(17p) treated in a clinical trial incorporating both conventional and thalidomide-based induction therapies was examined. The clinical impact of deletion, low expression, and mutation of TP53 was also determined. Patients with del(17p) did not have inferior response rates compared to patients without del(17p), but, despite this, del(17p) was associated with impaired overall survival (OS) (median OS 26.6 vs. 48.5 months, P <0.001). Within the del(17p) group, thalidomide induction therapy was associated with improved response rates compared to conventional therapy, but there was no impact on OS. Thalidomide maintenance was associated with impaired OS, although our analysis suggests that this effect may have been due to confounding variables. A minimally deleted region on 17p13.1 involving 17 genes was identified, of which only TP53 and SAT2 were underexpressed. TP53 was mutated in <1% in patients without del(17p) and in 27% of patients with del(17p). The higher TP53 mutation rate in samples with del(17p) suggests a role for TP53 in these clinical outcomes. In conclusion, del(17p) defined a patient group associated with short survival in myeloma, and although thalidomide induction therapy was associated with improved response rates, it did not impact OS, suggesting that alternative therapeutic strategies are required for this group. (C) 2011 Wiley-Liss, Inc.
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Modelling of massive stars and supernovae (SNe) plays a crucial role in understanding galaxies. From this modelling we can derive fundamental constraints on stellar evolution, mass-loss processes, mixing, and the products of nucleosynthesis. Proper account must be taken of all important processes that populate and depopulate the levels (collisional excitation, de-excitation, ionization, recombination, photoionization, bound–bound processes). For the analysis of Type Ia SNe and core collapse SNe (Types Ib, Ic and II) Fe group elements are particularly important. Unfortunately little data is currently available and most noticeably absent are the photoionization cross-sections for the Fe-peaks which have high abundances in SNe. Important interactions for both photoionization and electron-impact excitation are calculated using the relativistic Dirac atomic R-matrix codes (DARC) for low-ionization stages of Cobalt. All results are calculated up to photon energies of 45 eV and electron energies up to 20 eV. The wavefunction representation of Co III has been generated using GRASP0 by including the dominant 3d7, 3d6[4s, 4p], 3p43d9 and 3p63d9 configurations, resulting in 292 fine structure levels. Electron-impact collision strengths and Maxwellian averaged effective collision strengths across a wide range of astrophysically relevant temperatures are computed for Co III. In addition, statistically weighted level-resolved ground and metastable photoionization cross-sections are presented for Co II and compared directly with existing work.
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Les concentrés de protéines de lait sont couramment utilisés comme ingrédients lors de la standardisation du lait de fromagerie. La concentration des protéines est généralement réalisée par ultrafiltration (UF) à l’aide de membranes polymériques ayant un seuil de coupure de 10 kDa, et ce, jusqu’à un facteur de concentration volumique de 3.5X. Dans l’optique d’améliorer l’efficience du procédé d’UF, l’étude avait pour but de caractériser l’impact du mode opératoire (pression transmembranaire constante (465 et 672 kPa) et flux constant) ainsi que la température (10°C et 50°C) sur la performance du système jusqu’à un facteur de concentration volumique de 3.6X. Le module de filtration à l’échelle pilote comprenait une membrane d’UF en polyéthersulfone de 10 kDa d’une surface de 2,04 m2. La performance du système a été caractérisée sur le flux de perméation, la sélectivité et la consommation énergétique totale. L’étude a montré que le flux de perméation était 1,9 fois plus élevé à une température de 50°C comparativement à 10°C lors de l’UF du lait. Le coefficient de rejet des protéines n’a pas été affecté significativement par la pression transmembranaire et la température (P< 0,05). L’effet de la température a été observé au niveau de la teneur en calcium, laquelle était plus élevée de 12% dans les rétentats générés à 50C. La consommation énergétique totale du système d’UF était plus élevée à 10C comparativement à 50C, représentant 0,32±0,02 et 0,26±0,04 kWh/kg rétentat respectivement. Les résultats montrent que le ratio d’efficience énergétique (rapport entre le flux de perméation et la consommation énergétique) optimal a été obtenu à faible pression transmembranaire constante et à 50C. L’approche développée dans le cadre de ce projet fournira des outils aux industriels laitiers pour améliorer l’éco-efficience de leurs procédés de séparation baromembranaire.
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Ria de Aveiro, a Portuguese coastal lagoon that exchanges water with the Atlantic Ocean, received the effluent from a chlor-alkali industry for over 50 years; consequently several tons of mercury had been buried in the sediments of an inner basin. To assess the importance (and seasonal variation) of the lagoon waters as carriers of mercury to the nearby coastal area, we measured total mercury levels in several compartments: in surface sediments, in surface and deep waters (including dissolved and particulate matter!, and in biota. Dissolved (reactive and total) mercury concentrations both in surface and deep waters were low (<1 to 15 ng L '). Mean mercury values in suspended particulate matter varied hetween 0.2 and 0.6 jxg g ' and in sediments between 1 and 9 ng g '. Aquatic organisms displayed levels below regulatory limits but exhibited some bioaccumulation of mercury, with concentrations ranging from 0.05 to 0.8 ^ig g ' Idry weight (dw)|. No seasonal pattern was found in this study for mercury-related determinations. Levels found in the estuary mouth during ebb tide provide evidence for the transport of mercury to the coastal zone. No significant changes in the partition of mercury between dissolved and particulate phases were found in the coastal waters in comparison with the values found in the estuary mouth. In spite of the high levels of mercury found inside some areas of the lagoon, the wide web of islands and channels allows some spreading of contaminants before they reach the coastal waters. Moreover, the low efficiency of local marine sediments in trapping mercury contributes to a dilution of mercury transported in suspended particulate matter over a broader area, reducing the impact in the nearby manne coastal zone.
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Background Early intervention services (EIS) comprise low-stigma, youth-friendly mental health teams for young people undergoing first-episode psychosis (FEP). Engaging with the family of the young person is central to EIS policy and practice. Aims By analysing carers' accounts of their daily lives and affective challenges during a relative's FEP against the background of wider research into EIS, this paper explores relationships between carers' experiences and EIS. Method Semi-structured longitudinal interviews with 80 carers of young people with FEP treated through English EIS. Results Our data suggest that EIS successfully aid carers to support their relatives, particularly through the provision of knowledge about psychosis and medications. However, paradoxical ramifications of these user-focused engagements also emerge; they risk leaving carers' emotions unacknowledged and compounding an existing lack of help-seeking. Conclusions By focusing on EIS's engagements with carers, this paper draws attention to an urgent broader question: as a continuing emphasis on care outside the clinic space places family members at the heart of the care of those with severe mental illness, we ask: who can, and should, support carers, and in what ways?
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Women are disproportionately affected by dementia, both in terms of developing dementia and becoming caregivers. We conducted an integrative review of English language literature of the issues affecting women in relation to dementia from an international perspective. The majority of relevant studies were conducted in high income countries, and none were from low-income countries. The effects of caregiving on health, wellbeing and finances are greater for women; issues facing women, particularly in low and middle-income countries need to be better understood. Research should focus on building resilience to help people adjust and cope long term.
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BACKGROUND The presence of oral diseases and disorders can produce an impact on the quality of life of preschool children and their parents, affecting their oral health and well-being. However, socioeconomic factors could confound this association, but it has not been yet tested at this age. OBJECTIVE To assess the impact of early childhood caries (ECC), traumatic dental injuries (TDI) and malocclusions on the oral health-related quality of life (OHRQoL) of children between 2 and 5 years of age adjusted by socioeconomic factors. METHODS Parents of 260 children answered the Early Childhood Oral Health Impact Scale (ECOHIS) (six domains) on their perception of the children's OHRQoL and socioeconomic conditions. Two calibrated dentists (κ>0.8) examined the severity of ECC according to dmft index, and children were categorized into: 0=caries free; 1-5=low severity; ≥6=high severity. TDI and malocclusions were examined according to Andreasen & Andreasen (1994) classification and for the presence or absence of three anterior malocclusion traits (AMT), respectively. OHRQoL was measured through ECOHIS domain and total scores, and poisson regression was used to associate the different factors with the outcome. RESULTS In each domain and overall ECOHIS scores, the severity of ECC showed a negative impact on OHRQoL (P<0.001). TDI and AMT did not show a negative impact on OHRQoL nor in each domain (P>0.05). The increase in the child's age, higher household crowding, lower family income and mother working out of home were significantly associated with OHRQoL (P<0.05). The multivariate adjusted model showed that the high severity of ECC (RR=3.81; 95% CI=2.66, 5.46; P<0.001) was associated with greater negative impact on OHRQoL, while high family income was a protective factor for OHRQoL (RR=0.93; 95% CI=0.87, 0.99; P<0.001). CONCLUSIONS The severity of ECC and a lower family income had a negative impact on the OHRQoL of preschool children and their parents.
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Building on previous research, the goal of this project was to identify significant influencing factors for the Iowa Department of Transportation (DOT) to consider in future updates of its Instructional Memorandum (I.M.) 3.213, which provides guidelines for determining the need for traffic barriers (guardrail and bridge rail) at secondary roadway bridges—specifically, factors that might be significant for the bridge rail rating system component of I.M. 3.213. A literature review was conducted of policies and guidelines in other states and, specifically, of studies related to traffic barrier safety countermeasures at bridges in several states. In addition, a safety impact study was conducted to evaluate possible non-driver-related behavior characteristics of crashes on secondary road structures in Iowa using road data, structure data, and crash data from 2004 to 2013. Statistical models (negative binomial regression) were used to determine which factors were significant in terms of crash volume and crash severity. The study found that crashes are somewhat more frequent on or at bridges possessing certain characteristics—traffic volume greater than 400 vehicles per day (vpd) (paved) or greater than 50 vpd (unpaved), bridge length greater than 150 ft (paved) or greater than 35 ft (unpaved), bridge width narrower than its approach (paved) or narrower than 20 ft (unpaved), and bridges older than 25 years (both paved and unpaved). No specific roadway or bridge characteristic was found to contribute to more serious crashes. The study also confirmed previous research findings that crashes with bridges on secondary roads are rare, low-severity events. Although the findings of the study support the need for appropriate use of bridge rails, it concludes that prescriptive guidelines for bridge rail use on secondary roads may not be necessary, given the limited crash expectancy and lack of differences in crash expectancy among the various combinations of explanatory characteristics.
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Jatropha-based biofuels have undergone a rapid boom-and-bust cycle in southern Africa. Despite strong initial support by governments, donors, and the private sector, there is a lack of empirical studies that compare the environmental and socioeconomic impacts of Jatropha’s two dominant modes of production: large plantations and smallholder-based projects. We apply a rapid ecosystem services assessment approach to understand the impact of two Jatropha projects that are still operational despite widespread project collapse across southern Africa: a smallholder-based project (BERL, Malawi) and a large plantation (Niqel, Mozambique). Our study focuses on changes in provisioning ecosystem services such as biofuel feedstock, food, and woodland products that can have important effects on human well-being locally. Qualitative information is provided for other regulating and cultural ecosystem services. Although at this stage no impact is tremendously positive or negative, both projects show some signs of viability and local poverty alleviation potential. However, their long-term sustainability is not guaranteed given low yields, uncertain markets, and some prevailing management practices.
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The West African Monsoon (WAM) and its representation in numerical models are strongly influenced by the Saharan Heat Low (SHL), a low-pressure system driven by radiative heating over the central Sahara and ventilated by the cold and moist inflow from adjacent oceans. It has recently been shown that a significant part of the southerly moisture flux into the SHL originates from convective cold pools over the Sahel. These density currents driven by evaporation of rain are largely absent in models with parameterized convection. This crucial issue has been hypothesized to contribute to the inability of many climate models to reproduce the variability of the WAM. Here, the role of convective cold pools approaching the SHL from the Atlas Mountains, which are a strong orographic trigger for deep convection in Northwest Africa, is analyzed. Knowledge about the frequency of these events, as well as their impact on large-scale dynamics, is required to understand their contribution to the variability of the SHL and to known model uncertainties. The first aspect is addressed through the development of an objective and automated method for the generation of multi-year climatologies not available before. The algorithm combines freely available standard surface observations with satellite microwave data. Representativeness of stations and influence of their spatial density are addressed by comparison to a satellite-only climatology. Applying this algorithm to data from automated weather stations and manned synoptic stations in and south of the Atlas Mountains reveals the frequent occurrence. On the order of 6 events per month are detected from May to September when the SHL is in its northernmost position. The events tend to cluster into several-days long convectively active periods, often with strong events on consecutive days. This study is the first to diagnose dynamical impacts of such periods on the SHL, based on simulations of two example cases using the Weather Research and Forecast (WRF) model at convection-permitting resolution. Sensitivity experiments with artificially removed cold pools as well as different resolutions and parameterizations are conducted. Results indicate increases in surface pressure of more than 1 hPa and significant moisture transports into the desert over several days. This moisture affects radiative heating and thus the energy balance of the SHL. Even though cold pool events north of the SHL are less frequent when compared to their Sahelian counterparts, it is shown that they gain importance due to their temporal clustering on synoptic timescale. Together with studies focusing on the Sahel, this work emphasizes the need for improved parameterization schemes for deep convection in order to produce more reliable climate projections for the WAM.
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Purpose: To evaluate if physical measures of noise predict image quality at high and low noise levels. Method: Twenty-four images were acquired on a DR system using a Pehamed DIGRAD phantom at three kVp settings (60, 70 and 81) across a range of mAs values. The image acquisition setup consisted of 14 cm of PMMA slabs with the phantom placed in the middle at 120 cm SID. Signal-to-noise ratio (SNR) and Contrast-tonoise ratio (CNR) were calculated for each of the images using ImageJ software and 14 observers performed image scoring. Images were scored according to the observer`s evaluation of objects visualized within the phantom. Results: The R2 values of the non-linear relationship between objective visibility score and CNR (60kVp R2 = 0.902; 70Kvp R2 = 0.913; 80kVp R2 = 0.757) demonstrate a better fit for all 3 kVp settings than the linear R2 values. As CNR increases for all kVp settings the Object Visibility also increases. The largest increase for SNR at low exposure values (up to 2 mGy) is observed at 60kVp, when compared with 70 or 81kVp.CNR response to exposure is similar. Pearson r was calculated to assess the correlation between Score, OV, SNR and CNR. None of the correlations reached a level of statistical significance (p>0.01). Conclusion: For object visibility and SNR, tube potential variations may play a role in object visibility. Higher energy X-ray beam settings give lower SNR but higher object visibility. Object visibility and CNR at all three tube potentials are similar, resulting in a strong positive relationship between CNR and object visibility score. At low doses the impact of radiographic noise does not have a strong influence on object visibility scores because in noisy images objects could still be identified.
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Background - For dose reduction actions, the principle of “image quality as good as possible” to “image quality as good as needed” requires to know whether the physical measures and visual image quality relate. Visual evaluation and objective physical measures of image quality can appear to be different. If there is no noticeable effect on the visual image quality with a low dose but there is a objective physical measure impact, then the overall dose may be reduced without compromising the diagnostic image quality. Low dose imaging can be used for certain types of observations, e.g. thoracic scoliosis, control after metal implantation for osteosynthesis, reviewing pneumonia and tuberculosis. Aim of the study - To determine whether physical measures of noise predict visual (clinical) image quality at low dose levels.