950 research outputs found

    Finding alternatives to swidden agriculture:Does agroforestry improve livelihood options and reduce pressure on existing forest?

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    Swidden cultivation can contribute to deforestation and land degradation, which can subsequently result in a number of serious environmental problems. This paper examines the economic and social potential of agroforestry systems and the barriers to their widespread adoption, as a land use alternative to swidden cultivation, which may potentially help protect local forest. The Gunung Salak valley in West Java, Indonesia is presented as a case study. Based on farmers� and experts� assessment, costs and benefits have been estimated, which show that the two investigated agroforestry systems have higher net present value and benefit-cost ratio (B/C) than the two swidden cultivation systems. Tree ownership also creates more permanent rights to farmland and is prestigious in the community. Agroforestry products (fruit, vegetables etc.) have high monetary value and help strengthen social cohesion when shared with neighbors. However, farmers are reluctant to implement agroforestry. Stated reasons are related to both culture and capacity. Farmers practicing agroforestry are less involved in forest clearing and forest products collection than swidden farmers indicating that it may contribute positively to conservation of local forests. Increasing the adoption of agroforestry farming in the study area will require support to overcome capacity constraint

    A regional water quality model designed for a range of users and for retrofit and re-use

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    We discuss the motivations for, and software design concepts underpinning, the development of a regional water quality model. The Environmental Management Support System (EMSS) was developed to predict daily fluxes of runoff, total suspended sediment, total nitrogen and total phosphorous through a large-scale river network. It was built using a custom environmental modelling framework called Tarsier, founded on the Borland C++ Builder rapid application development environment. Three autonomous models are integrated within the EMSS, but are loosely coupled so that alternative models could be retrofitted into the system if desired. The three models share common data handling and visualisation routines resident in the Tarsier modelling environment and used in other modelling applications. The EMSS was designed for use by a range of stakeholders with varying levels of computer and technical proficiency. To satisfy their varying needs, we built three different interfaces, suited to ‘expert’, ‘intermediate’ and ‘basic’ users. The interfaces for the latter two groups were developed using interface prototyping methods, resulting in software that suited the user requirements. The object-oriented design employed in the coding of the EMSS has enhanced the extendibility and re-useability of the software. The EMSS development was part of a larger hydrologic modelling initiative aimed at reducing duplication in model building and standardising approaches to model design and delivery. The lessons learned during development of the EMSS have informed our future model development strategy

    Chronic Obstructive Pulmonary Disease: Lobar Analysis with Hyperpolarized 129Xe MR Imaging.

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    Purpose To compare lobar ventilation and apparent diffusion coefficient (ADC) values obtained with hyperpolarized xenon 129 ((129)Xe) magnetic resonance (MR) imaging to quantitative computed tomography (CT) metrics on a lobar basis and pulmonary function test (PFT) results on a whole-lung basis in patients with chronic obstructive pulmonary disease (COPD). Materials and Methods The study was approved by the National Research Ethics Service Committee; written informed consent was obtained from all patients. Twenty-two patients with COPD (Global Initiative for Chronic Obstructive Lung Disease stage II-IV) underwent hyperpolarized (129)Xe MR imaging at 1.5 T, quantitative CT, and PFTs. Whole-lung and lobar (129)Xe MR imaging parameters were obtained by using automated segmentation of multisection hyperpolarized (129)Xe MR ventilation images and hyperpolarized (129)Xe MR diffusion-weighted images after coregistration to CT scans. Whole-lung and lobar quantitative CT-derived metrics for emphysema and bronchial wall thickness were calculated. Pearson correlation coefficients were used to evaluate the relationship between imaging measures and PFT results. Results Percentage ventilated volume and average ADC at lobar (129)Xe MR imaging showed correlation with percentage emphysema at lobar quantitative CT (r = -0.32, P < .001 and r = 0.75, P < .0001, respectively). The average ADC at whole-lung (129)Xe MR imaging showed moderate correlation with PFT results (percentage predicted transfer factor of the lung for carbon monoxide [Tlco]: r = -0.61, P < .005) and percentage predicted functional residual capacity (r = 0.47, P < .05). Whole-lung quantitative CT percentage emphysema also showed statistically significant correlation with percentage predicted Tlco (r = -0.65, P < .005). Conclusion Lobar ventilation and ADC values obtained from hyperpolarized (129)Xe MR imaging demonstrated correlation with quantitative CT percentage emphysema on a lobar basis and with PFT results on a whole-lung basis. (©) RSNA, 2016

    Superconductivity and Electronic Structure of Perovskite MgCNi3

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    The electronic structure, stability, electron phonon coupling and superconductivity of the non-oxide perovskite MgCNi3_3 are studied using density functional calculations. The band structure is dominated by a Ni dd derived density of states peak just below the Fermi energy, which leads to a moderate Stoner enhancement, placing MgCNi3_3 in the range where spin fluctuations may noticeably affect transport, specific heat and superconductivity, providing a mechanism for reconciling various measures of the coupling λ\lambda. Strong electron phonon interactions are found for the octahedral rotation mode and may exist for other bond angle bending modes. The Fermi surface contains nearly cancelling hole and electron sheets that give unusual behavior of transport quantities particularly the thermopower. The results are discussed in relation to the superconductivity of MgCNi3_3.Comment: 4 pages, RevTex, 5 ps figure

    Impedimetric Characterization of Bipolar Nanoelectrodes with Cancer Cells

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    Merging of electronics with biology, defined as bioelectronics, at the nanoscale holds considerable promise for sensing and modulating cellular behavior. Advancing our understanding of nanobioelectronics will facilitate development and enable applications in biosensing, tissue engineering, and bioelectronic medicine. However, studies investigating the electrical effects when merging wireless conductive nanoelectrodes with biology are lacking. Consequently, a tool is required to develop a greater understanding of merging conductive nanoparticles with cells. Herein, this challenge is addressed by developing an impedimetric method to evaluate bipolar electrode (BPE) systems that could report on electrical input. A theoretical framework is provided, using impedance to determine if conductive nanoparticles can be polarized and used to drive current. It is then demonstrated that 125 nm of gold nanoparticle (AuNP) bipolar electrodes (BPEs) could be sensed in the presence of cells when incorporated intracellularly at 500 μg/mL using water and phosphate-buffered saline (PBS) as electrolytes. These results highlight how nanoscale BPEs act within biological systems. This research will impact the rational design of using BPE systems in cells for both sensing and actuating applications

    Contribution of Color Information in Visual Saliency Model for Videos

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    International audienceMuch research has been concerned with the contribution of the low level features of a visual scene to the deployment of visual attention. Bottom-up saliency models have been developed to predict the location of gaze according to these features. So far, color besides to brightness, contrast and motion is considered as one of the primary features in computing bottom-up saliency. However, its contribution in guiding eye movements when viewing natural scenes has been debated. We investigated the contribution of color information in a bottom-up visual saliency model. The model efficiency was tested using the experimental data obtained on 45 observers who were eye tracked while freely exploring a large data set of color and grayscale videos. The two datasets of recorded eye positions, for grayscale and color videos, were compared with a luminance-based saliency model. We incorporated chrominance information to the model. Results show that color information improves the performance of the saliency model in predicting eye positions

    Development of a population-based microsimulation model of osteoarthritis in Canada

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    OBJECTIVES: The purpose of the study was to develop a population-based simulation model of osteoarthritis (OA) in Canada that can be used to quantify the future health and economic burden of OA under a range of scenarios for changes in the OA risk factors and treatments. In this article we describe the overall structure of the model, sources of data, derivation of key input parameters for the epidemiological component of the model, and preliminary validation studies. DESIGN: We used the Population Health Model (POHEM) platform to develop a stochastic continuous-time microsimulation model of physician-diagnosed OA. Incidence rates were calibrated to agree with administrative data for the province of British Columbia, Canada. The effect of obesity on OA incidence and the impact of OA on health-related quality of life (HRQL) were modeled using Canadian national surveys. RESULTS: Incidence rates of OA in the model increase approximately linearly with age in both sexes between the ages of 50 and 80 and plateau in the very old. In those aged 50+, the rates are substantially higher in women. At baseline, the prevalence of OA is 11.5%, 13.6% in women and 9.3% in men. The OA hazard ratios for obesity are 2.0 in women and 1.7 in men. The effect of OA diagnosis on HRQL, as measured by the Health Utilities Index Mark 3 (HUI3), is to reduce it by 0.10 in women and 0.14 in men. CONCLUSIONS: We describe the development of the first population-based microsimulation model of OA. Strengths of this model include the use of large population databases to derive the key parameters and the application of modern microsimulation technology. Limitations of the model reflect the limitations of administrative and survey data and gaps in the epidemiological and HRQL literature

    Malignant pleural effusion: current understanding and therapeutic approach

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    Malignant pleural effusion (MPE) is a common complication of thoracic and extrathoracic malignancies and is associated with high mortality and elevated costs to healthcare systems. Over the last decades the understanding of pathophysiology mechanisms, diagnostic techniques and optimal treatment intervention in MPE have been greatly advanced by recent high-quality research, leading to an ever less invasive diagnostic approach and more personalized management. Despite a number of management options, including talc pleurodesis, indwelling pleural catheters and combinations of the two, treatment for MPE remains symptom directed and centered around drainage strategy. In the next future, because of a better understanding of underlying tumor biology together with more sensitive molecular diagnostic techniques, it is likely that combined diagnostic and therapeutic procedures allowing near total outpatient management of MPE will become popular. This article provides a review of the current advances, new discoveries and future directions in the pathophysiology, diagnosis and management of MPE
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