853 resultados para Low-impact camping
Resumo:
Background: Colorectal cancers (CRCs) may be categorised according to the degree of microsatellite instability (MSI) exhibited, as MSI-high (MSI-H), MSI-low (MSI-L), or microsatellite stable (MSS). MSI-H status confers a survival advantage to patients with sporadic CRC. Aims: To determine if low levels of MSI are related to the clinicopathological features and prognosis of sporadic stage C CRC. Patients: A total of 255 patients who underwent resection for sporadic stage C CRC were studied. No patient received chemotherapy. Minimum follow up was five years. Methods: DNA extracted from archival malignant and non-malignant tissue was amplified by polymerase chain reaction using a panel of 11 microsatellites. MSI-H was defined as instability at greater than or equal to40% of markers, MSS as no instability, and MSI-L as instability at >0% but,40% of markers. Patients with MSI-H CRC were excluded from analysis as they have previously been shown to have better survival. Results: Thirty three MSI-L and 176 MSS CRCs were identified. There was no difference in biological characteristics or overall survival of MSI-L compared with MSS CRC but MSI-L was associated with poorer cancer specific survival (hazard ratio 2.0 (95% confidence interval 1.1-3.6)). Conclusions: Sporadic MSI-L and MSS CRCs have comparable clinicopathological features. Further studies are required to assess the impact of MSI-L on prognosis.
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Low concentrations of herbicides (up to 70 ng 1(-1)), chiefly diuron (up to 50 ng 1 (-1)) were detected in surface waters associated with inter-tidal seagrass meadows of Zostera muelleri in Hervey Bay, south-cast Queensland, Australia. Diuron and atrazine (up to 1. 1 ng g(-1) dry weight of sediment) were detected in the sediments of these seagrass meadows. Concentration of the herbicides diuron, simazine and atrazine increased in surface waters associated with seagrass meadows during moderate river flow events indicating herbicides were washed from the catchment to the marine environment. Maximum herbicide concentration (sum of eight herbicides) in the Mary River during a moderate river flow event was 4260 ng 1(-1). No photosynthetic stress was detected in seagrass in this study during low river flow. However, with moderate river flow events, nearshore seagrasses are at risk of being exposed to concentrations of herbicides that are known to inhibit photosynthesis. (c) 2004 Elsevier Ltd. All rights reserved.
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The discovery of the Woodleigh impact structure, first identified by R. P. lasky, bears a number of parallels with that of the Chlcxulub impact structure of K-T boundary age, underpinning complications inherent in the study of buried impact structures by geophysical techniques and drilling. Questions raised in connection with the diameter of the Woodleigh impact structure reflect uncertainties in criteria used to define original crater sizes in eroded and buried impact structures as well as limits on the geological controls at Woodleigh. The truncation of the regional Ajona - Wandagee gravity ridges by the outer aureole of the Woodleigh structure, a superposed arcuate magnetic anomaly along the eastern part of the structure, seismic-reflection data indicating a central > 37 km-diameter dome, correlation of fault patterns between Woodleigh and less-deeply eroded impact structures (Ries crater, Chesapeake Bay), and morphometric estimates all indicate a final diameter of 120 km. At Woodleigh, pre-hydrothermal shock-induced melting and diaplectic transformations are heavily masked by pervasive alteration of the shocked gneisses to montmorillonite-dominated clays, accounting for the high MgO and low K2O of cryptocrystalline components. The possible contamination of sub-crater levels of the Woodlelgh impact structure by meteoritic components, suggested by high Ni, Co, Cr, Ni/ Co and Ni/Cr ratios, requires further siderophile element analyses of vein materials. Although stratigraphic age constraints on the impact event are broad (post-Middle Devonian to pre-Early Jurassic) high-temperature (200-250 degrees C) pervasive hydrothermal activity dated by K-Ar isotopes of illite - smectite indicates an age of 359 +/- 4 Ma. To date neither Late Devonian crater fill, nor impact ejecta fallout units have been identified, although metallic meteoritic ablation spherules of a similar age have been found in the Conning Basin.
Resumo:
Hydrothermally altered shock-metamorphosed gneisses consisting of relic igneous biotite-K-feldspor-Na-rich alkali feldspar - plagioclase - quartz assemblages ( accessory garnet, corundum, titanite, monazite, zircon), and showing extensive replacement by montmorillonite, illite, sericite, and to a lesser extent chlorite, calcite, epidote, zoisite and pyrite, occur in the basement core uplift of the Woodleigh impact structure, Western Australia. The rocks display extensive hydrothermal clay alteration, complicating identification of pre-hydrothermal and pre-impact textures and compositions. Analysis of quartz-hosted planar deformation features (PDFs) indicates a majority of indexed sets parallel to omega{10 (1) over bar3}, a lesser abundance of sets parallel to pi{10 (1) over bar2}, and some sets parallel to the basal plane (0001) and r,z {10 (1) over bar1}, consistent with pressures about or over 20 GPa. Feldspar-hosted FDFs form reticulate vein networks displaying checkerboard-like to irregular and serrated patterns attributable to preferential replacement of shock-damaged PDFs and/or perthitic twin lamella by clay minerals. The gneisses are pervaded by clay-dominated intergranular and intragranular veins of cryptocrystalline material that display marked departures from bulk-rock chemistry and from mineral compositions. XRD analysis identifies the cryptocrystalline components as illite - montmorillonite, illite and chlorite, while laser Raman analysis identifies high-fluorescence sub-micrometre clay assemblage, feldspar, quartz and minor mica. SEM/EDS-probe and laser-ICPMS analysis indicate low-K high-Mg clay mineral compositions consistent with montmorillonite. Quartz PDF-hosted cryptocrystalline laminae display distinct enrichments in Al, Mg, Ca and K. Altered intergranular veins and feldspar-hosted cryptocrystalline components show consistent enrichment in the relatively refractory elements (Al, Cc, Mg, Fe) and depletion in relatively volatile elements (Si, K, Na). The clay alteration retards determination whether clay-dominated vein networks represent altered shock-induced pseudotachylite veins, diaplectic zones and/or shock-damaged twin lamella, and/or result from purely mineralogical and chemical differentiation affected by hydrothermal fluids, Overall enrichment of the shocked gneiss and of the cryptocrystalline components in Mg and trace ferromagnesian elements (Ni, Cc, Cr) may be attributed alternatively to introduction of siderophile element-rich fluid from the projectile, or/and contamination of hydrothermal fluids by MgO from dolomites surrounding the basement uplift. High Ni/Co and Ni/Cr and anomalous DGE (platinum group elements) may support the former model.
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According to Leader-Member Exchange (LMX) theory, leaders develop different quaUt}' reladonships with the employees they supervise. To date, Utde research has invesdgated the impact of such differendadon by the leader on workplace outcomes. The current research proposes a novel way to capture the extent of LMX variabiUt}' within a single work team, and subsequently investigates the impact of perceived LMX variability on workplace outcomes. Across multiple employed samples, participants reported poorer team relations (as indicated by low team cohesion and high conflict) when they perceived LMX variability to be high. Perceptions of poor team relations further impacted negatively upon individual affect variables. The findings suggest that leaders may need to exercise caution when developing different quality relationships amongst individuals within the same work team.
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This paper examines the extent to which foreign direct investment (FDI) in selected UK manufacturing sectors has an impact on reported profits in domestic firms. Foreign manufacturing firms are characterized by relatively high labour productivity and low wage shares. Entry by foreign firms not only impacts on domestic market shares, but also on domestic cost conditions. As a result, profitability in the indigenous sector may be reduced. There are a number of policy implications of this analysis which are explored.
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Recent studies of US industrial modernisation programmes argue that difficulties of establishing long-term relationships with users prevent them from facilitating development of innovation capabilities. The paper supports this argument through a survey of Japanese research institutes the US programmes were modelled on. In view of information asymmetries in their use, it tests the hypothesis that small and medium-sized firms start using the research institutes with ‘low information gap’ services and gradually move on to ‘high information gap’ services that often require more absorptive capacity. This is demonstrated both under one-to-one relationships and between groups of firms and a research institute.
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The effect of low energy nitrogen molecular ion beam bombardment on metals and compound semiconductors has been studied, with the aim to investigate at the effects of ion and target properties. For this purpose, nitrogen ion implantation in aluminium, iron, copper, gold, GaAs and AIGaAs is studied using XPS and Angle Resolve XPS. A series of experimental studies on N+2 bombardment induced compositional changes, especially the amount of nitrogen retained in the target, were accomplished. Both monoenergetic implantation and non-monoenergetic ion implantation were investigated, using the VG Scientific ESCALAB 200D system and a d. c. plasma cell, respectively. When the samples, with the exception of gold, are exposed to air, native oxide layers are formed on the surfaces. In the case of monoenergetic implantation, the surfaces were cleaned using Ar+ beam bombardment prior to implantation. The materials were then bombarded with N2+ beam and eight sets of successful experiments were performed on each sample, using a rastered N2+ ion beam of energy of 2, 3, 4 and 5 keV with current densities of 1 μA/cm2 and 5 μA/cm22 for each energy. The bombarded samples were examined by ARXPS. After each complete implantation, XPS depth profiles were created using Ar+ beam at energy 2 ke V and current density 2 μA/cm2 . As the current density was chosen as one of the parameters, accurate determination of current density was very important. In the case of glow discharge, two sets of successful experiments were performed in each case, by exposing the samples to nitrogen plasma for the two conditions: at low pressure and high voltage and high pressure and low voltage. These samples were then examined by ARXPS. On the theoretical side, the major problem was prediction of the number of ions of an element that can be implanted in a given matrix. Although the programme is essentially on experimental study, but an attempt is being made to understand the current theoretical models, such as SATVAL, SUSPRE and TRIM. The experimental results were compared with theoretical predictions, in order to gain a better understanding of the mechanisms responsible. From the experimental results, considering possible experimental uncertainties, there is no evidence of significant variation in nitrogen saturation concentration with ion energy or ion current density in the range of 2-5 ke V, however, the retention characteristics of implantant seem to strongly depend on the chemical reactivity between ion species and target material. The experimental data suggests the presence of at least one thermal process. The discrepancy between the theoretical and experimental results could be the inability of the codes to account for molecular ion impact and thermal processes.
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An experimental and theoretical study of the impact behaviour of charged microparticles in a high voltage vacuum gap has been carried out to investigate under controlled conditions the role of low velocity microparticles (ζ 500 ms-1) in initiating electrical breakdown in such gaps. This has involved developing a unique (UHV) low-velocity source of micron-sized charged particles to study the underlying mechanical and electrical aspects of micro-particle impact on a range of target materials e.g. Pb, Ti, C, stainless-steel and mica etc., having atomically clean or oxidised surfaces. Argon-ion etching and electron-beam heating has been used for in-situ surface treatment and ellipsometry for characterising the target surfaces. An associated sphere/plane theoretical model has been developed for detailed analysis of the many complex electrical (in-flight in-field emission, M.I.M. tunnelling and ohmic conduction) and mechanical (impact dynamics, deformation and heating) phenomena that are involved when a microparticle closely approaches and impacts on a plane target. In each instance the influence of parameters such as particle radius, particle/target impact velocity, surface field, surface condition and material has been determined.
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The thesis begins with a conceptual model of the way that language diversity affects the strategies, organisation and subsidiary control policies of multinational companies. The model is based solely on the researcher'’ personal experience of working in a variety of international management roles, but in Chapter 2 a wide-ranging review of related academic literature finds evidence to support the key ideas. The model is developed as a series of propositions which are tested in a comparative case study, refined and then re-tested in a global survey of multinational subsidiaries. The principal findings of the empirical phases of the thesis endorse the main tenets of the model: - That language difference between parent and subsidiary will impair communication, create mistrust and impede relationship development. - That subsequently the feelings of uncertainty, suspicion and mistrust will influence the decisions taken by the parent company. - They will have heightened sensitivity to language issues and will implement policies to manage language differences. - They will adopt low-risk strategies in host countries where they are concerned about language difference. - They will use organisational and manpower strategies to minimise the consequences and risks of the communications problems with the subsidiary. - As a consequence the level of integration and knowledge flow between parent and subsidiary will be curtailed. - They will adopt styles of control that depend least on their ability to communicate with their subsidiary. Although there is adequate support for all of the above conclusions, on some key points the evidence of the Case Studies and Survey is contradictory. The thesis, therefore, closes with an agenda for further research that would address these inconsistencies.
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Using prescription analyses and questionnaires, the way drug information was used by general medical practitioners during the drug adoption process was studied. Three new drugs were considered; an innovation and two 'me-too' products. The innovation was accepted by general practitioners via a contagion process, information passing among doctors. The 'me-too' preparations were accepted more slowly and by a process which did not include the contagion effect. 'Industrial' information such as direct mail was used more at the 'awareness' stage of the adoption process while 'professional' sources of information such as articles in medical journals were used more to evaluate a new product. It was shown that 'industrial' information was preferred by older single practice doctors who did not specialise, had a first degree only and who did not dispense their own prescriptions. Doctors were divided into early and late-prescribers by using the date they first prescribed the innovatory drug. Their approach to drug information sources was further studied and it was shown that the early-prescriber issued slightly more prescriptions per month, had a larger list size, read fewer journals and generally rated industrial sources of information more highly than late-prescribers. The prescribing habits of three consultant rheumatologists were analysed and compared with those of the general practitioners in the community which they served. Very little association was noted and the influence of the consultant on the prescribing habits of general practitioners was concluded to be low. The consultants influence was suggested to be of two components, active and passive; the active component being the most influential. Journal advertising and advertisement placement were studied for one of the 'me-too' drugs. It was concluded that advertisement placement should be based on the reading patterns of general practitioners and not on ad-hoc data gathered by representatives as was the present practice. A model was proposed relating the 'time to prescribe' a new drug to the variables suggested throughout this work. Four of these variables were shown to be significant. These were, the list size, the medical age of the prescriber, the number of new preparations prescribed in a given time and the number of partners in the practice.
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Offering important counterpoint to work identifying team influences stimulating creative expression of individual differences in goal orientation, we develop cross-level theory establishing that team bureaucratic practices (centralization and formalization) constrain creative expression. Speaking to the tension between bureaucracy and creativity, findings indicate that this influence is not only negative and that effects of centralization and formalization differ. Surveying 330 employees in 95 teams at the Taiwan Customs Bureau, we found that learning and "performance avoid" goal orientations had, respectively, stronger positive and weaker negative relationships with creativity under low centralization. A "performance- prove" orientation was positively related to creativity under low formalization. © Academy of Management Journal.
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This study investigated the role of differences in age, organizational tenure and gender between manager and employee as potential moderators between employees' leader-member exchanges (LMX) and related work outcomes. The results support the interaction effect of manager-employee organizational tenure difference with LMX and outcome variables. Employees with a high organizational tenure difference from the manager reported the worst work outcomes when they perceived LMX was of low quality, whereas when the quality of LMX was high, they reported the highest work attitudes and well-being.
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We report for the first time on the limitations in the operational power range of few-mode fiber based transmission systems, employing 28Gbaud quadrature phase shift keying transponders, over 1,600km. It is demonstrated that if an additional mode is used on a preexisting few-mode transmission link, and allowed to optimize its performance, it will have a significant impact on the pre-existing mode. In particular, we show that for low mode coupling strengths (weak coupling regime), the newly added variable power mode does not considerably impact the fixed power existing mode, with performance penalties less than 2dB (in Q-factor). On the other hand, as mode coupling strength is increased (strong coupling regime), the individual launch power optimization significantly degrades the system performance, with penalties up to ∼6dB. Our results further suggest that mutual power optimization, of both fixed power and variable power modes, reduces power allocation related penalties to less than 3dB, for any given coupling strength, for both high and low differential mode delays. © 2013 Optical Society of America.