1,040 research outputs found

    ForestSim model of impacts of smallholder dynamics: forested landscapes of the Upper Peninsula of Michigan

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    Many forested landscapes in the United States contain a large number of small private landowners (smallholders). The individual decisions of these smallholders can collectively have a large impact on the structure, composition, and connectivity of forests. While models have been developed to try to understand this large-scale collective impact, few models have incorporated extensive information from individual decision-making. Here we introduce an agent-based model, infused with sociological data from smallholders, overlaid on a GIS layer to represent individual smallholders, and used to simulate the impact of thousands of harvesting decisions. Our preliminary results suggest that certain smallholder characteristics (such as relative smallholder age and education level as well as whether a smallholder is resident or absentee) and information flow among owners can radically impact forests at the landscape scale. While still in its preliminary stages, this modeling approach is likely to demonstrate in detail the consequences of decision-making due to changing smallholder demographics or new policies and programs. This approach can help estimate the effectiveness of programs based on landscape-scale programmatic goals and the impact of new policy initiatives

    Aquaponics: A Sustainable Food Production System That Provides Research Projects for Undergraduate Engineering Students

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    Aquaponics is a closed-loop, recirculating water system in which plants and fish grow together mutualistically. Aquaponics resembles a natural river or lake basin in which fish waste serves as nutrients for the plants, which in turn clean the water for the fish. Tilapia and salad greens or herbs are common fish and plants grown in an aquaponics system. The external inputs to an aquaponics system are fish food, minimal amount of water, and energy for lighting and heating the water for the fish and plants. Aquaponics is a sustainable, efficient system to raise fish protein and vegetables for human consumption. Aquaponics systems can be located anywhere in the world where there is adequate energy with a minimal amount of water. Aquaponics is particularly suited to arid climates because it uses much less water to grow plants than soil-based systems. In fact, the only water that is lost is evaporation and transpiration from the plants. Although the field of aquaponics is growing world-wide, the capital and operational costs of producing the plants and fish have not been quantified intensively in the peer-reviewed literature. The relationship between the amount of external energy (fish food plus energy for light and heat) to the output (weight of fish and plants) has not been measured well for aquaponics units in temperate climates. The lack of quantification of the input-output has suppressed aquaponics progress because it is difficult to compare the cost of fish and salad greens grown with aquaponics and conventional methods, such as aquaculture and soil-based methods. The diverse nature of aquaponics and the need to quantify the relationship between input-output presents opportunities for research projects for undergraduate engineering students in Mechanical, Electrical, and Civil Engineering. The following are examples: Sensors: What type of sensors are ideal to measure air and water temperature, water PH, dissolved O2, and nitrates? Thermodynamics: What type of water heating system is most efficient to maintain desirable water and air temperature? Water Quality: What are the optimal methods to filter out the solid fish waste (feces) and introduce necessary bacteria into the system? Hydraulics: What size of pump and diameter of pipe are needed to maintain optimal flow rate? System Design: What are the optimal ratios between fish tank volume and grow area volume? What is the optimal drop in water level between components to utilize the gravity system? Marquette University College of Engineering is building a laboratory to conduct aquaponics research. The design of the system along with the lessons learned will be presented, along with a detailed list of specific projects for engineering students. Lessons learned from this research will aid the development of aquaponics in temperate climates but also possibly in subtropical and tropical region

    Structural determinants of allosteric regulation in alternatively spliced AMPA receptors

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    AbstractThe flip and flop splice variants of AMPA receptors show strikingly different sensitivity to allosteric regulation by cyclothiazide; heteromers assembled from GluR-A and GIuR-B also exhibit splice variant-dependent differences in efficacy for activation by glutamate and kainate. The sensitivity for attenuation of desensitization by cyclothiazide for homomeric GIuR-A was solely dependent upon exchange of Ser-750 (flip) and Asn-750 (flop), and was unaffected by mutagenesis of other divergent residues. In contrast, substantial alteration of the relative efficacy of glutamate versus kainate required mutation of multiple residues in the flip/flop region. Modulation by cyclothiazide was abolished by mutation of Ser-750 to Gin, the residue found at the homologous site in kainate-preferring subunits, whereas introduction of Ser at this site in GIuR6 imparted sensitivity to cyclothiazide

    Progress in the study of CdZnTe strip detectors

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    We report new performance measurements and computer simulations of a sub-millimeter pitch CdZnTe strip detector under study as a prototype imaging spectrometer for astronomical x-ray and gamma-ray observations. The prototype is 1.5 mm thick with 375 micron strip pitch in both the x and y dimensions. Previously reported work included demonstrations of half-pitch spatial resolution (approximately 190 microns) and good energy resolution and spectral uniformity. Strip detector efficiency measurements have also been presented. A model that includes the photon interaction, carrier transport and the electronics was developed that qualitatively reproduced the measurements. The new studies include measurements of the CdZnTe transport properties for this prototype in an effort to resolve quantitative discrepancies between the measurements and the simulations. Measurements of charge signals produced by laser pulses and (alpha) -rays are used to determine these transport properties. These are then used in the model to predict gamma-ray efficiencies that are compared with the data. The imaging performance of the detector is studied by scanned laser and gamma beam spot measurements. The results support the model\u27s prediction of nearly linear sharing of the charge for interactions occurring in the region between electrodes. The potential for strip detectors with spatial resolution much finer than the strip pitch is demonstrated. A new design scheme for strip detectors is shortly discussed

    Impact of a brief faculty training to improve patient-centered communication while using electronic health records

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    Objective Despite rapid EHR adoption, few faculty receive training in how to implement patient-centered communication skills while using computers in exam rooms. We piloted a patient-centered EHR use training to address this issue. Methods Faculty received four hours of training at Cleveland Clinic and a condensed 90-minute version at the University of Chicago. Both included a lecture and a Group-Objective Structured Clinical Exam (GOSCE) experience. Direct observations of 10 faculty in their clinical practices were performed pre- and post-workshop. Results Thirty participants (94%) completed a post-workshop evaluation assessing knowledge, attitude, and skills. Faculty reported that training was important, relevant, and should be required for all providers; no differences were found between longer versus shorter training. Participants in the longer training reported higher GOSCE efficacy, however shorter workshop participants agreed more with the statement that they had gained new knowledge. Faculty improved their patient-centered EHR use skills in clinical practice on post- versus pre-workshop ratings using a validated direct-observation rating tool. Conclusion A brief lecture and GOSCE can be effective in training busy faculty on patient-centered EHR use skills. Practice Implications Faculty training on patient-centered EHR skills can enhance patient-doctor communication and promotes positive role modeling of these skills to learners

    A prospective cohort study in patients with type 2 diabetes mellitus for validation of biomarkers (PROVALID) –study design and baseline characteristics

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    Background/Aims: The prevalence of diabetes mellitus type 2 and kidney disease in these patients varies widely between European countries. Methods: In addition to store biosamples the “Prospective cohort study in patients with type 2 diabetes mellitus for validation of biomarkers” collects information on history, physical status, laboratory measurements and medication in 4000 patients with diabetes mellitus type 2, being taken care of at the primary level of healthcare in 5 European countries (Austria, Hungary, Netherlands, Poland and Scotland). Next to comparing the rate of loss of eGFR between the countries, a further objective of the PROVALID study is to determine the 5-year cumulative incidence of renal and cardiovascular outcomes. Results: The mean age of the population recruited is 62.9±10 years, 54.6% are male and the mean BMI is 30.9±5.4 kg/m2 . Metabolic control (median HBA1c 6.8 % (6.2;7.5)) is achieved via administration of metformin in 67.4% of the patients and insulin in 30.3%. Median systolic and diastolic blood pressure at recruitment is 135 (125;146) and 80 (72;85) mmHg, 65.4% of subjects received RAAS blocking agents. Mean eGFR is 80.7±29.2 ml/min/1.73m2 and median baseline albumin/creatinine ratio 8.3 mg (IQR: 3.8 and 25.1). Conclusion: PROVALID will provide information on incidence and progression of renal and cardiovascular disease and therapy in patients with type 2 diabetes mellitus in different European countries. Thus, in contrast to many other cohort studies we will be able to associate national clinical practise pattern with outcome in this highly vulnerable patient population

    CdZnTe strip detectors as sub-millimeter resolution imaging gamma radiation spectrometers

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    We report γ-ray detection performance measurements and computer simulations of a sub-millimeter pitch CdZnTe strip detector. The detector is a prototype for γ-ray measurements in the range of 20-600 keV. The prototype is a 1.5 mm thick, 64×64 orthogonal stripe CdZnTe detector of 0.375 mm pitch in both dimensions, with approximately one square inch of sensitive area. Using discrete laboratory electronics to process signals from an 8×8 stripe region of the prototype we measured good spectroscopic uniformity and sub-pitch (~0.2 mm) spatial resolution in both x and y dimensions. We present below measurements of the spatial uniformity, relative timing and pulse height of the anode and cathode signals. We simulated the photon interactions and signal generation in the strip detector and the test electronics and we compare these results with the data. The data indicate that cathode signal-as well as the anode signal-arises more strongly from the conduction electrons rather than the holes

    Performance of CdZnTe strip detectors as sub-millimeter resolution imaging gamma radiation spectrometers

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    We report & gamma;-ray detection performance measurements and computer simulations of a sub-millimeter pitch CdZnTe strip detector. The detector is a prototype for & gamma;-ray astronomy measurements in the range of 20-200 keV. The prototype is a 1.5 mm thick, 64×64 orthogonal stripeCdZnTe detector of 0.375 mm pitch in both dimensions, with approximately one square inch of sensitive area. Using discrete laboratory electronics to process signals from an 8×8 stripe region of the prototype we measured good spectroscopic uniformity and sub-pitch (~0.2 mm) spatial resolution in both x and y dimensions. We present below measurements of the spatial uniformity, relative timing and pulse height of the anode and cathode signals, and the photon detection efficiency. We also present a technique for determining the location of the event in the third dimension (depth). We simulated the photon interactions and signal generation in the strip detector and the test electronics and we compare these results with the data. The data indicate that the cathode signal-as well as the anode signal-arises more strongly from the conduction electrons rather than the holes
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