996 resultados para Geological surveys.


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Since 1973, English Heritage has supported four major regional surveys of England's wetlands- in the Somerset Levels, the Fens of Eastern England, the wetlands of the northwest of England and the Humber wetlands. Each of these projects developed a range of methods and techniques particular to the landscape that was studied and the results from the surveys reflect this diversity of approach. This paper compares and contrast these approaches, and evaluates their effect on the overall results of each of these surveys.

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Electrical methods of geophysical survey are known to produce results that are hard to predict at different times of the year, and under differing weather conditions. This is a problem which can lead to misinterpretation of archaeological features under investigation. The dynamic relationship between a ‘natural’ soil matrix and an archaeological feature is a complex one, which greatly affects the success of the feature’s detection when using active electrical methods of geophysical survey. This study has monitored the gradual variation of measured resistivity over a selection of study areas. By targeting difficult to find, and often ‘missing’ electrical anomalies of known archaeological features, this study has increased the understanding of both the detection and interpretation capabilities of such geophysical surveys. A 16 month time-lapse study over 4 archaeological features has taken place to investigate the aforementioned detection problem across different soils and environments. In addition to the commonly used Twin-Probe earth resistance survey, electrical resistivity imaging (ERI) and quadrature electro-magnetic induction (EMI) were also utilised to explore the problem. Statistical analyses have provided a novel interpretation, which has yielded new insights into how the detection of archaeological features is influenced by the relationship between the target feature and the surrounding ‘natural’ soils. The study has highlighted both the complexity and previous misconceptions around the predictability of the electrical methods. The analysis has confirmed that each site provides an individual and nuanced situation, the variation clearly relating to the composition of the soils (particularly pore size) and the local weather history. The wide range of reasons behind survey success at each specific study site has been revealed. The outcomes have shown that a simplistic model of seasonality is not universally applicable to the electrical detection of archaeological features. This has led to the development of a method for quantifying survey success, enabling a deeper understanding of the unique way in which each site is affected by the interaction of local environmental and geological conditions.

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In this article we assess the abilities of a new electromagnetic (EM) system, the CMD Mini-Explorer, for prospecting of archaeological features in Ireland and the UK. The Mini-Explorer is an EM probe which is primarily aimed at the environmental/geological prospecting market for the detection of pipes and geology. It has long been evident from the use of other EM devices that such an instrument might be suitable for shallow soil studies and applicable for archaeological prospecting. Of particular interest for the archaeological surveyor is the fact that the Mini-Explorer simultaneously obtains both quadrature (‘conductivity’) and in-phase (relative to ‘magnetic susceptibility’) data from three depth levels. As the maximum depth range is probably about 1.5 m, a comprehensive analysis of the subsoil within that range is possible. As with all EM devices the measurements require no contact with the ground, thereby negating the problem of high contact resistance that often besets earth resistance data during dry spells. The use of the CMD Mini-Explorer at a number of sites has demonstrated that it has the potential to detect a range of archaeological features and produces high-quality data that are comparable in quality to those obtained from standard earth resistance and magnetometer techniques. In theory the ability to measure two phenomena at three depths suggests that this type of instrument could reduce the number of poor outcomes that are the result of single measurement surveys. The high success rate reported here in the identification of buried archaeology using a multi-depth device that responds to the two most commonly mapped geophysical phenomena has implications for evaluation style surveys. Copyright © 2013 John Wiley & Sons, Ltd.

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Background Appropriately conducted adaptive designs (ADs) offer many potential advantages over conventional trials. They make better use of accruing data, potentially saving time, trial participants, and limited resources compared to conventional, fixed sample size designs. However, one can argue that ADs are not implemented as often as they should be, particularly in publicly funded confirmatory trials. This study explored barriers, concerns, and potential facilitators to the appropriate use of ADs in confirmatory trials among key stakeholders. Methods We conducted three cross-sectional, online parallel surveys between November 2014 and January 2015. The surveys were based upon findings drawn from in-depth interviews of key research stakeholders, predominantly in the UK, and targeted Clinical Trials Units (CTUs), public funders, and private sector organisations. Response rates were as follows: 30(55 %) UK CTUs, 17(68 %) private sector, and 86(41 %) public funders. A Rating Scale Model was used to rank barriers and concerns in order of perceived importance for prioritisation. Results Top-ranked barriers included the lack of bridge funding accessible to UK CTUs to support the design of ADs, limited practical implementation knowledge, preference for traditional mainstream designs, difficulties in marketing ADs to key stakeholders, time constraints to support ADs relative to competing priorities, lack of applied training, and insufficient access to case studies of undertaken ADs to facilitate practical learning and successful implementation. Associated practical complexities and inadequate data management infrastructure to support ADs were reported as more pronounced in the private sector. For funders of public research, the inadequate description of the rationale, scope, and decision-making criteria to guide the planned AD in grant proposals by researchers were all viewed as major obstacles. Conclusions There are still persistent and important perceptions of individual and organisational obstacles hampering the use of ADs in confirmatory trials research. Stakeholder perceptions about barriers are largely consistent across sectors, with a few exceptions that reflect differences in organisations’ funding structures, experiences and characterisation of study interventions. Most barriers appear connected to a lack of practical implementation knowledge and applied training, and limited access to case studies to facilitate practical learning. Keywords: Adaptive designs; flexible designs; barriers; surveys; confirmatory trials; Phase 3; clinical trials; early stopping; interim analyses

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Objectives. To describe the changes in the use of maternal and child health care services by residents of three municipalities-Embu, Itapecerica da Serra, and Taboao da Serra-in the Sao Paulo metropolitan area, 12 years after the implementation of the Unified Health System (SUS) in Brazil, and to analyze the potential of population-based health care surveys as sources of data to evaluate these changes. Methods. Two population-based, cross-sectional surveys were carried out in 1990 and 2002 in municipalities located within the Sao Paulo metropolitan area. For children under 1 year of age, the two periods were compared in terms of outpatient services utilization and hospital admission; for the mothers, the periods were compared in terms of prenatal care and deliveries. In both surveys, stratified and multiple-stage conglomerate sampling was employed, with standardization of interview questions. Results. The most important changes observed were regarding the location of services used for prenatal care, deliveries, and hospitalization of children less than 1 year of age. There was a significant increase in the use of services in the surrounding region or hometown, and decrease in the utilization of services in the city of Sao Paulo (in 1990, 80% of deliveries and almost all admissions for children less than 1 year versus 32% and 46%, respectively, in 2002). The use of primary care units and 24-hour walk-in clinics also increased. All these changes reflect care provided by public resources. In the private sector, there was a decrease in direct payments and payments through company-paid health insurance and an increase in payments through self-paid health insurance. Conclusions. The major changes observed in the second survey occurred simultaneous to the changes that resulted from the implementation of the SUS. Population-based health surveys are adequate for analyzing and comparing the utilization of health care services at different times.

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P>Estimates of effective elastic thickness (T(e)) for the western portion of the South American Plate using, independently, forward flexural modelling and coherence analysis, suggest different thermomechanical properties for the same continental lithosphere. We present a review of these T(e) estimates and carry out a critical reappraisal using a common methodology of 3-D finite element method to solve a differential equation for the bending of a thin elastic plate. The finite element flexural model incorporates lateral variations of T(e) and the Andes topography as the load. Three T(e) maps for the entire Andes were analysed: Stewart & Watts (1997), Tassara et al. (2007) and Perez-Gussinye et al. (2007). The predicted flexural deformation obtained for each T(e) map was compared with the depth to the base of the foreland basin sequence. Likewise, the gravity effect of flexurally induced crust-mantle deformation was compared with the observed Bouguer gravity. T(e) estimates using forward flexural modelling by Stewart & Watts (1997) better predict the geological and gravity data for most of the Andean system, particularly in the Central Andes, where T(e) ranges from greater than 70 km in the sub-Andes to less than 15 km under the Andes Cordillera. The misfit between the calculated and observed foreland basin subsidence and the gravity anomaly for the Maranon basin in Peru and the Bermejo basin in Argentina, regardless of the assumed T(e) map, may be due to a dynamic topography component associated with the shallow subduction of the Nazca Plate beneath the Andes at these latitudes.

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Three soil profiles in Ilha Solteira, Brazil were investigated to establish their potential for collapsible behavior. The soil profiles were identified using terrain evaluation techniques and simple laboratory tests. Geophysical surveys were undertaken as they are quick and relatively cheap. The results were correlated with trial pit descriptions and cone and standard penetration tests. The study has shown that electrical resistivity is a useful tool for the preliminary identification of horizons of collapsible soils, before more expensive intrusive and laboratory work is undertaken.

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A comparison of dengue virus (DENV) antibody levels in paired serum samples collected from predominantly DENV-naive residents in an agricultural settlement in Brazilian Amazonia (baseline seroprevalence, 18.3%) showed a seroconversion rate of 3.67 episodes/100 person-years at risk during 12 months of follow-up. Multivariate analysis identified male sex, poverty, and migration from extra-Amazonian states as significant predictors of baseline DENY seropositivity, whereas male sex, a history of clinical diagnosis of dengue fever, and travel to an urban area predicted subsequent seroconversion. The laboratory surveillance of acute febrile illnesses implemented at the study site and in a nearby town between 2004 and 2006 confirmed 11. DENV infections among 102 episodes studied with DENV IgM detection, reverse transcriptase-polymerise chain reaction, and virus isolation; DENV-3 was isolated. Because DENV exposure is associated with migration or travel, personal protection measures when visiting high-risk urban areas may reduce the incidence of DENV infection in this rural population.

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Models of dynamical dark energy unavoidably possess fluctuations in the energy density and pressure of that new component. In this paper we estimate the impact of dark energy fluctuations on the number of galaxy clusters in the Universe using a generalization of the spherical collapse model and the Press-Schechter formalism. The observations we consider are several hypothetical Sunyaev-Zel`dovich and weak lensing (shear maps) cluster surveys, with limiting masses similar to ongoing (SPT, DES) as well as future (LSST, Euclid) surveys. Our statistical analysis is performed in a 7-dimensional cosmological parameter space using the Fisher matrix method. We find that, in some scenarios, the impact of these fluctuations is large enough that their effect could already be detected by existing instruments such as the South Pole Telescope, when priors from other standard cosmological probes are included. We also show how dark energy fluctuations can be a nuisance for constraining cosmological parameters with cluster counts, and point to a degeneracy between the parameter that describes dark energy pressure on small scales (the effective sound speed) and the parameters describing its equation of state.

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Earthen mounds with archaeological artifacts have been well known in Marajo Island since the 19th century. Their documented dimensions are impressive, e.g., up to 20m high, and with areas large as 90 ha. The mounds, locally known as lesos, impose a significant. relief on the very low-lying landscape of this region, which averages 4 to 6 in above present. sea level. These features have been traditionally interpreted as artificial constructions of the Marajoara culture, designed for defense, cemetery purposes, or escape from flooding. Here, we provide sedimentological and geomorphological data that suggest an alternative origin for these structures that is more consistent with their monumental sizes. Rather than artificial, the Marajoara tesos seem to consist of natural morphological features related to late Pleistocene and Holocene fluvial, and possibly tidal-influenced, paleochannels and paleobars that became abandoned as depositional conditions changed through dine. Although utilized and modified by the Marajoara since at least 2000 years ago, these earthen mounds contain a significant non-anthropogenically modified sedimentary substratum. Therefore, the large Marajoara tesos are not entirely artificial. Ancient, Marajoara cultures took advantage of these natural, preexisting elevated surfaces to base their communities and develop their activities, locally increasing the sizes of these fluvial landforms. This alternative interpretation suggests less cumulative labor investment, in the construction of the mounds and might. have significant implications for reconstructing the organization of the Marajoara culture. (C) 2009 Wiley Periodicals, Inc.

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The terms ‘Leptodus Shales’ and ‘Leptodus Beds’ have been used to describe a rich brachiopod bearing unit within the Permian argillaceous facies of the Central Belt of Peninsular Malaysia. To date there has been no formal description of this unit regarding its age, spatial distribution or faunal composition. A review of previous literature, backed by recently collected data from our field surveys and biostratigraphical studies reveals that there is a sequence of fossiliferous assemblages within the Leptodus Shales, which range in age from Middle Permian to possibly early Late Permian and extend geographically from southern Kelantan to southern Pahang, Peninsular Malaysia. These assemblages are found in argillaceous sediments which are often highly tuffaceous, and in northern Pahang are associated with pyroclastic volcanics of probable island-arc origin. The faunas are of Palaeo-equatorial affinity and are taxonomically close to faunas in Indochina, such as the Sisophon fauna in Cambodia. Typical elements include Vediproductus cf. punctatiformis (Chao), Transennatia gratiosa (Waagen), T. termierorum Sone, Leman and Shi, Uncuninellina timorensis (Beyrich), Leptodus richthofeni Kayser, L. cf. tenuis (Waagen), Leptodus nobilis (Waagen), Gubleria aff. ninglangensis Fang and Jiang, and Spyridiophora gubleri Termier and Termier.

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The aim of this article is to contribute to the development of our  understanding of two aspects of attitude change in Australia. First, both cohort and individual explanations for attitude change are tested empirically. Second, empirical evidence is provided about the nature and scope of change in gender role attitudes amongst males and females, and of different birth cohorts in Australia, as reported in two survey periods: 1994 and 2002. In particular, the question of whether there is empirical evidence of cohort differences in attitudes to gender roles in Australia is investigated. TheThe aim of this article is to contribute to the development of our understanding of two aspects of attitude change in Australia. First, both cohort and individual explanations for attitude change are tested empirically. Second, empirical evidence is provided about the nature and scope of change in gender role attitudes amongst males and females, and of different birth cohorts in Australia, as reported in two survey periods: 1994 and 2002. In particular, the question of whether there is empirical evidence of cohort differences in attitudes to gender roles in Australia is investigated. The findings show that birth cohorts display progressively more modern attitudes, but people tend not to change their attitudes as they get older. In addition, men and women have different attitudes to gender roles, with men displaying more traditional beliefs than women. Having more than one child makes women less inclined to express the belief that women should work.