966 resultados para VERTICAL ZONATION


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We study the interaction between a magnetic dipole mimicking the Gerasimovich magnetic anomaly on the lunar surface and the solar wind in a self-consistent 3-D quasi-neutral hybrid simulation where ions are modeled as particles and electrons as a charge-neutralizing fluid. Especially, we consider the origin of the recently observed electric potentials at lunar magnetic anomalies. An antimoonward Hall electric field forms in our simulation resulting in a potential difference of <300V on the lunar surface, in which the value is similar to observations. Since the hybrid model assumes charge neutrality, our results suggest that the electric potentials at lunar magnetic anomalies can be formed by decoupling of ion and electron motion even without charge separation.

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PURPOSE Dyslexia is the most common developmental reading disorder that affects language skills. Latent strabismus (heterophoria) has been suspected to be causally involved. Even though phoria correction in dyslexic children is commonly applied, the evidence in support of a benefit is poor. In order to provide experimental evidence on this issue, we simulated phoria in healthy readers by modifying the vergence tone required to maintain binocular alignment. METHODS Vergence tone was altered with prisms that were placed in front of one eye in 16 healthy subjects to induce exophoria, esophoria, or vertical phoria. Subjects were to read one paragraph for each condition, from which reading speed was determined. Text comprehension was tested with a forced multiple choice test. Eye movements were recorded during reading and subsequently analyzed for saccadic amplitudes, saccades per 10 letters, percentage of regressive (backward) saccades, average fixation duration, first fixation duration on a word, and gaze duration. RESULTS Acute change of horizontal and vertical vergence tone does neither significantly affect reading performance nor reading associated eye movements. CONCLUSION Prisms in healthy subjects fail to induce a significant change of reading performance. This finding is not compatible with a role of phoria in dyslexia. Our results contrast the proposal for correcting small angle heterophorias in dyslexic children.

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Studies of memory-guided saccades in monkeys show an upward bias, while studies of antisaccades in humans show a diagonal effect, a deviation of endpoints toward the 45° diagonal. To determine if these two different spatial biases are specific to different types of saccades, we studied prosaccades, antisaccades and memory-guided saccades in humans. The diagonal effect occurred not with prosaccades but with antisaccades and memory-guided saccades with long intervals, consistent with hypotheses that it originates in computations of goal location under conditions of uncertainty. There was a small upward bias for memory-guided saccades but not prosaccades or antisaccades. Thus this bias is not a general effect of target uncertainty but a property specific to memory-guided saccades.

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In the aftermath of the devastating civil war, the Sierra Leonean government created favourable conditions for foreign investors willing to lease large areas of land to bring development to the country. A team of anthropologists and geographers did extensive fieldwork on the Addax Bioenergy Project in order to a) document the project affected people’s (PAP) perceptions and interests on a horizontal level and b) identify the different actors that are necessary for the implementation of such a project on the vertical level. Findings indicate that the project triggers a number of processes: Cultural and linguistic differences between PAP and company, their diverse understanding of development and the stance of local elites led to misunderstandings concerning each other’s responsibilities and created a lot of frustration on both sides. Further, the loss of natural resources that comes along with the land lease affects mostly women and other vulnerable groups.

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Despite an increased scientific interest in the relatively new phenomenon of large-scale land acquisition (LSLA), data on processes on the local level remain sparse and superficial. However, knowledge about the concrete implementation of LSLA projects and the different impacts they have on the heterogeneous group of project affected people is indispensable for a deepened understanding of the phenomenon. In order to address this research gap, a team of two anthropologists and a human geographer conducted in-depth fieldwork on the LSLA project of Swiss based Addax Bioenergy in Sierra Leone. After the devastating civil war, the Sierra Leonean government created favourable conditions for foreign investors willing to lease large areas of land and to bring “development” to the country. Being one of the numerous investing companies, Addax Bioenergy has leased 57’000 hectares of land to develop a sugarcane plantation and an ethanol factory to produce biofuel for the export to the European market. Based on participatory observation, qualitative interview techniques and a network analysis, the research team aimed a) at identifying the different actors that were necessary for the implementation of this project on a vertical level and b) exploring various impacts of the project in the local context of two villages on a horizontal level. The network analysis reveals a complex pattern of companies, institutions, nongovernmental organisations and prominent personalities acting within a shifting technological and discursive framework linking global scales to a unique local context. Findings from the latter indicate that affected people initially welcomed the project but now remain frustrated since many promises and expectations have not been fulfilled. Although some local people are able to benefit from the project, the loss of natural resources that comes along with the land lease affects livelihoods of vulnerable groups – especially women and land users – considerably. However, this research doesn’t only disclose impacts on local people’s previous lives but also addresses strategies they adopt in the newly created situation that has opened up alternative spaces for renegotiations of power and legitimatisation. Therewith, this explorative study reveals new aspects of LSLA that have not been considered adequately by the investing company nor by the general academic discourse on LSLA.

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Despite increased scientific interest in the phenomenon of large-scale land acquisitions (LSLA), accurate data on implementation processes remain sparse. This paper aims at filling this gap by providing empirical in-depth knowledge on the case of the Swiss-based Addax Bioenergy Ltd. in Sierra Leone. Extensive fieldwork allowed the interdisciplinary research team 1) the identification of different actors that are necessary for the implementation on a vertical level and 2) the documentation of the heterogeneous group of project affected people’s perceptions and strategies on a horizontal level. Findings reveal that even a project labeled as best-practice example by UN agencies triggers a number of problematic processes for affected communities. The loss of natural resources that comes along with the land lease and the lack of employment possibilities mostly affects already vulnerable groups. On the other hand, strategies and resistance of local people also affect the project implementation. This shows that the horizontal and vertical levels are not separate entities. They are linked by social networks, social interactions, and means of communication and both levels take part in shaping the project’s impacts.

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Since 2003 a melting ice field on the Schnidejoch pass (2756 a.s.l) delivered several hundred objects from the Neolithic, the Bronze and Iron Age as well as from Roman and Early Medieval times. The oldest finds date to the beginning 5th millennium BC, the youngest ones date around 1000 AD. Most of the objects stem from the Neolithic and the Bronze Age and are of organic origin. A series of more than 70 radiocarbon dates confirms that the Schnidejoch pass, linking the Bernese Highlands with the River Rhone valley, was in use at least from 4800–4500 BC on. The accessibility of the pass was easy when the glaciers descending from the nearby Wildhorn mountain range (peak on 3248 a.s.l) were in a retreating phase. In contrary glacier advances closed the way to the pass. In 2010 a palaeoecological study of sediment cores researched nearby Lake Iffig (2065 m a.s.l.). The results show clear indications of early human impact in this alpine area. Linking archaeological finds from Schnidejoch pass and River Rhone valley with the palaeoecological data can be interpreted as early indications of alpine pastoralism and transhumance. The combined archaeological and paleoecolical research allows to explain vertical mobility in the Swiss Alps.

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In most habitats, vegetation provides the main structure of the environment. This complexity can facilitate biodiversity and ecosystem services. Therefore, measures of vegetation structure can serve as indicators in ecosystem management. However, many structural measures are laborious and require expert knowledge. Here, we used consistent and convenient measures to assess vegetation structure over an exceptionally broad elevation gradient of 866–4550m above sea level at Mount Kilimanjaro, Tanzania. Additionally, we compared (human)-modified habitats, including maize fields, traditionally managed home gardens, grasslands, commercial coffee farms and logged and burned forests with natural habitats along this elevation gradient. We distinguished vertical and horizontal vegetation structure to account for habitat complexity and heterogeneity. Vertical vegetation structure (assessed as number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) displayed a unimodal elevation pattern, peaking at intermediate elevations in montane forests, whereas horizontal structure (assessed as coefficient of variation of number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) was lowest at intermediate altitudes. Overall, vertical structure was consistently lower in modified than in natural habitat types, whereas horizontal structure was inconsistently different in modified than in natural habitat types, depending on the specific structural measure and habitat type. Our study shows how vertical and horizontal vegetation structure can be assessed efficiently in various habitat types in tropical mountain regions, and we suggest to apply this as a tool for informing future biodiversity and ecosystem service studies.

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Leaf-herbivory can lead to systemic changes in root metabolism and resistance. As yet, it is unknown if these changes affect the whole root system, or if they are more pronounced in the upper root parts, which are closer to the actual site of attack. As this spatial aspect may be an important determinant of the interactions that can be expected to occur within the rhizosphere, we investigated if leaf-herbivore induced root resistance differs between upper and lower roots of maize. We also tested if the density of leaf-herbivores correlates with intensity of the root response. The systemic increase in resistance was found to be more pronounced in the upper than the lower roots and was independent of leaf herbivore density. The results suggest that there is a vertical gradient in the strength of the root response following leaf-herbivory, and that soil organisms living closer to the surface may be more affected by leaf-attack than the ones living in deeper soil layers.

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Visual exploration of natural scenes imposes demands that differ between the upper and the lower visual hemifield. Yet little is known about how ocular motor performance is affected by the location of visual stimuli or the direction of a behavioural response. We compared saccadic latencies between upper and lower hemifield in a variety of conditions, including short-latency prosaccades, long-latency prosaccades, antisaccades, memory-guided sac- cades and saccades with increased attentional and selection demand. All saccade types, except memory guided saccades, had shorter latencies when saccades were directed to- wards the upper field as compared to downward saccades (p<0.05). This upper field reaction time advantage probably arises in ocular motor rather than visual processing. It may originate in structures involved in motor preparation rather than execution.

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PURPOSE In the present case series, the authors report on seven cases of erosively worn dentitions (98 posterior teeth) which were treated with direct resin composite. MATERIALS AND METHODS In all cases, both arches were restored by using the so-called stamp technique. All patients were treated with standardized materials and protocols. Prior to treatment, a waxup was made on die-cast models to build up the loss of occlusion as well as ensure the optimal future anatomy and function of the eroded teeth to be restored. During treatment, teeth were restored by using templates of silicone (ie, two "stamps," one on the vestibular, one on the oral aspect of each tooth), which were filled with resin composite in order to transfer the planned, future restoration (ie, in the shape of the waxup) from the extra- to the intraoral situation. Baseline examinations were performed in all patients after treatment, and photographs as well as radiographs were taken. To evaluate the outcome, the modified United States Public Health Service criteria (USPHS) were used. RESULTS The patients were re-assessed after a mean observation time of 40 months (40.8 ± 7.2 months). The overall outcome of the restorations was good, and almost exclusively "Alpha" scores were given. Only the marginal integrity and the anatomical form received a "Charlie" score (10.2%) in two cases. CONCLUSION Direct resin composite restorations made with the stamp technique are a valuable treatment option for restoring erosively worn dentitions.

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A three-level satellite to ground monitoring scheme for conservation easement monitoring has been implemented in which high-resolution imagery serves as an intermediate step for inspecting high priority sites. A digital vertical aerial camera system was developed to fulfill the need for an economical source of imagery for this intermediate step. A method for attaching the camera system to small aircraft was designed, and the camera system was calibrated and tested. To ensure that the images obtained were of suitable quality for use in Level 2 inspections, rectified imagery was required to provide positional accuracy of 5 meters or less to be comparable to current commercially available high-resolution satellite imagery. Focal length calibration was performed to discover the infinity focal length at two lens settings (24mm and 35mm) with a precision of O.1mm. Known focal length is required for creation of navigation points representing locations to be photographed (waypoints). Photographing an object of known size at distances on a test range allowed estimates of focal lengths of 25.lmm and 35.4mm for the 24mm and 35mm lens settings, respectively. Constants required for distortion removal procedures were obtained using analytical plumb-line calibration procedures for both lens settings, with mild distortion at the 24mm setting and virtually no distortion found at the 35mm setting. The system was designed to operate in a series of stages: mission planning, mission execution, and post-mission processing. During mission planning, waypoints were created using custom tools in geographic information system (GIs) software. During mission execution, the camera is connected to a laptop computer with a global positioning system (GPS) receiver attached. Customized mobile GIs software accepts position information from the GPS receiver, provides information for navigation, and automatically triggers the camera upon reaching the desired location. Post-mission processing (rectification) of imagery for removal of lens distortion effects, correction of imagery for horizontal displacement due to terrain variations (relief displacement), and relating the images to ground coordinates were performed with no more than a second-order polynomial warping function. Accuracy testing was performed to verify the positional accuracy capabilities of the system in an ideal-case scenario as well as a real-world case. Using many welldistributed and highly accurate control points on flat terrain, the rectified images yielded median positional accuracy of 0.3 meters. Imagery captured over commercial forestland with varying terrain in eastern Maine, rectified to digital orthophoto quadrangles, yielded median positional accuracies of 2.3 meters with accuracies of 3.1 meters or better in 75 percent of measurements made. These accuracies were well within performance requirements. The images from the digital camera system are of high quality, displaying significant detail at common flying heights. At common flying heights the ground resolution of the camera system ranges between 0.07 meters and 0.67 meters per pixel, satisfying the requirement that imagery be of comparable resolution to current highresolution satellite imagery. Due to the high resolution of the imagery, the positional accuracy attainable, and the convenience with which it is operated, the digital aerial camera system developed is a potentially cost-effective solution for use in the intermediate step of a satellite to ground conservation easement monitoring scheme.

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Vertical integration is grounded in economic theory as a corporate strategy for reducing cost and enhancing efficiency. There were three purposes for this dissertation. The first was to describe and understand vertical integration theory. The review of the economic theory established vertical integration as a corporate cost reduction strategy in response to environmental, structural and performance dimensions of the market. The second purpose was to examine vertical integration in the context of the health care industry, which has greater complexity, higher instability, and more unstable demand than other industries, although many of the same dimensions of the market supported a vertical integration strategy. Evidence on the performance of health systems after integration revealed mixed results. Because the market continues to be turbulent, hybrid non-owned integration in the form of alliances have increased to over 40% of urban hospitals. The third purpose of the study was to examine the application of vertical integration in health care and evaluate the effects. The case studied was an alliance formed between a community hospital and a tertiary medical center to facilitate vertical integration of oncology services while maintaining effectiveness and preserving access. The economic benefits for 1934 patients were evaluated in the delivery system before and after integration with a more detailed economic analysis of breast, lung, colon/rectal, and non-malignant cases. A regression analysis confirmed the relationship between the independent variables of age, sex, location of services, race, stage of disease, and diagnosis, and the dependent variable, cost. The results of the basic regression model, as well as the regression with first-order interaction terms, were statistically significant. The study shows that vertical integration at an intermediate health care system level has economic benefits. If the pre-integration oncology group had been treated in the post-integration model, the expected cost savings from integration would be 31.5%. Quality indicators used were access to health care services and research treatment protocols, and access was preserved in the integrated model. Using survival as a direct quality outcome measure, the survival of lung cancer patients was statistically the same before and after integration. ^

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Submitted in partial fulfillment of the requirements for a Certificate in Orthodontics, Dept. of Orthodontics, University of Connecticut Health Center, 1986