2,473 research outputs found
A PLL frequency synthesizer and Gilbert cell multiplier for a 916 MHz ISM band transmitter realized in 0.5 [mu]m [i.e. micrometer] CMOS technology
This thesis is a study of the design of a 3rd order phase lock loop (PLL) and Gilbert cell multiplier to implement a 916MHz ISM band transmitter in 0.5μm CMOS technology. The transmitter is designed for implementing distributed biosensor systems for environmental monitoring.
The transmitter is described from a system level with the discussion of design issues concerning system topology and communication signal requirements as related to project requirements. The PLL system is described as a negative feedback system and important design considerations are discussed. Each PLL and transmitter system component is analyzed and discussed. A prototyped double balanced Gilbert cell multiplier with a power gain of 8dB, -10dBm compression point, and dissipates 7.2mW of power is analyzed and presentedThe analysis and design of a prototyped current mode logic frequency divider with a fixed division factor of 256 is presented. The frequency divider dissipated 15mW of power for a -20dBm 916 MHz input signal with a maximum operating frequency of 1.8 GHz. An off-chip LC tank voltage controlled oscillator was prototyped with a tuning range of 120 MHz, dissipated 3.3mW, -15dBm single-ended output signal, and had a phase noise performance of -60dBc at a 10 kHz offset and -80dBc at 100 kHz offset is analyzed and presentedThe design and simulation issues of a digital phase frequency detector (PFD), charge pump, and loop filter is presented. The charge pump was designed to source or sink a 10 μA current for an output voltage to within 0.1 V of the power supply voltages. Results show that the final transmitter can be successfully implemented with the prototyped and simulated transmitter components
Information and Economic Efficiency
Is an economy with adverse selection, moral hazard, or an incomplete set of risk markets "constrained" Pareto efficient? There are two sets of papers addressing this question, one asserting that, under seemingly quite general conditions, the economy is constrained Pareto efficient, the other (to which we have contributed), that it is not. In this paper, we delineate the differences in assumptions between the two sets of papers, and under our assumptions present an intuitive proof of the Pareto inefficiency of market equilibrium with moral hazard and identify what it is that the government can do that the market cannot
Bioclimatic and Soil Moisture Monitoring Across Elevation in a Mountain Watershed: Opportunities for Research and Resource Management
Soil moisture data are critical to understanding biophysical and societal impacts of climate change. However, soil moisture data availability is limited due to sparse in situ monitoring, particularly in mountain regions. Here we present methods, specifications, and initial results from the interactive Roaring Fork Observation Network (iRON), a soil, weather, and ecological monitoring system in the Southern Rocky Mountains of Colorado. Initiated in 2012, the network is currently composed of nine stations, distributed in elevation from 1,890 to 3,680 m, that continually collect and transmit measurements of soil moisture at three depths (5, 20, and 50 cm), soil temperature (20 cm), and meteorological conditions. Time‐lapse cameras for phenological observations, snow depth sensors, and periodic co‐located vegetation surveys complement selected stations. iRON was conceived and designed with the joint purpose of supporting bioclimatic research and resource management objectives in a snow‐dominated watershed. In the short term, iRON data can be applied to assessing the impact of temperature and precipitation on seasonal soil moisture conditions and trends. As more data are collected over time, iRON will help improve understanding of climate‐driven changes to soil, vegetation, and hydrologic conditions. In presenting this network and its initial data, we hope that the network’s elevational gradient will contribute to bioclimatic mountain research, while active collaboration with partners in resource management may provide a model for science‐practice interaction in support of long‐term monitoring.Plain Language SummaryAs climate change drives shifts in temperature and precipitation, researchers and resource managers can benefit from improved monitoring of soil moisture. Understanding the relationship between soil moisture and other system components is crucial to improving water availability projections and understanding ecosystem responses to climate change. Despite their significance, in‐ground soil‐moisture measurements are often not available across multiple elevations within a single watershed. This paper presents a network in the Southern Rocky Mountains intended to help address this data gap and compliment data from other networks. The interactive Roaring Fork Observation Network consists of nine locations across an 1,800‐m change in elevation. Each station measures soil moisture at three depths, soil temperature, air temperature, humidity, and precipitation. Some stations are equipped with cameras or snow depth gauges, and for eight sites vegetation surveys are conducted. The data are available through a simple data portal. The network was established with local resource manager support, and one of its guiding purposes is to support management and restoration planning efforts. Because of the network’s ongoing monitoring across multiple elevations and habitats, interactive Roaring Fork Observation Network will provide researchers and resource managers with access to valuable information about changes in soil conditions in a changing climate.Key PointsSoil moisture is key to understanding and predicting change in hydrology and ecology amid climate variability and changeIn situ soil moisture and weather monitoring data are now available across an 1,800‐m elevation span in a mountain watershedThe network is supported and guided by resource managers and supports both research and resource management goalsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149210/1/wrcr23834_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149210/2/wrcr23834.pd
The role of sodium glucose cotransporter-2 inhibitors in atherosclerotic cardiovascular disease: A narrative review of potential mechanisms
Sodium glucose cotransporter 2 (SGLT2) inhibitors are a class of medication with broad cardiovascular benefits in those with type 2 diabetes, chronic kidney disease, and heart failure. These include reductions in major adverse cardiac events and cardiovascular death. The mechanisms that underlie their benefits in atherosclerotic cardiovascular disease (ASCVD) are not well understood, but they extend beyond glucose lowering. This narrative review summarises the ASCVD benefits of SGLT2 inhibitors seen in large human outcome trials, as well as the mechanisms of action explored in rodent and small human studies. Potential pathways include favourable alterations in lipid metabolism, inflammation, and endothelial function. These all require further investigation in large human clinical trials with mechanistic endpoints, to further elucidate the disease modifying benefits of this drug class and those who will benefit most from it
The closer, the better? Untangling scientist-practitioner engagement, interaction, and knowledge use
Photoacoustic and nephelometric spectroscopy of aerosol optical properties with a supercontinuum light source
A novel multi-wavelength photoacousticnephelometer spectrometer (SC-PNS) has been developed for the optical characterization of atmospheric aerosol particles. This instrument integrates a white light supercontinuum laser with photoacoustic and nephelometric spectroscopy to measure aerosol absorption and scattering coefficients at five wavelength bands (centered at 417, 475, 542, 607, and 675 nm). These wavelength bands are selected from the continuous spectrum of the laser (ranging from 400-2200 nm) using a set of optical interference filters. Absorption and scattering measurements on laboratory-generated aerosol samples were performed sequentially at each wavelength band. To test the instrument we measured the wavelength dependence of absorption and scattering coefficients of kerosene soot and common salt aerosols. Results were favorably compared to those obtained with a commercial 3-wavelength photoacoustic and nephelometer instrument demonstrating the utility of the SC light source for studies of aerosol optical properties at selected wavelengths. Here, we discuss instrument design, development, calibration, performance and experimental results
Estimating the Economic Value of Australian Stock Herding Dogs
This study aimed to estimate the value of the typical Australian herding dog in terms of predicted return on investment. This required an assessment of the costs associated with owning herding dogs and estimation of the work they typically perform. Data on a total of 4,027 dogs were acquired through The Farm Dog Survey which gathered information from 812 herding dog owners around Australia. The median cost involved in owning a herding dog was estimated to be a total of AU40,000. So, herding dogs typically provided their owners with a 5.2-fold return on investment. When respondents were asked to nominate the maximal, one-off, veterinary expenditure they would consider to remedy an illness or injury for an especially valued dog, the median response was AU$1,001–2,000 which is not concordant with the dogs’ calculated median lifetime value. The current findings equip working dog owners with useful information to make financially appropriate expenditure decisions related to their working dogs. This is expected to increase farm profitability and improve welfare for farm dogs
Assessing knowledge of healthcare providers concerning cardiovascular risk after hypertensive disorders of pregnancy: an Australian national survey.
BACKGROUND:Hypertensive disorders of pregnancy (HDP) affect 5-10% of pregnant women. Women after HDP have 2-3 times increased risk of heart attack, stroke and diabetes, as soon as 5-10 years after pregnancy. Australian healthcare providers' knowledge of cardiovascular disease (CVD) risks for women after HDP is unknown, and this study aimed to explore their current knowledge and practice regarding long-term cardiovascular health after HDP, as a precursor to producing targeted healthcare provider education on health after HDP. METHODS:A custom-created, face-validated online survey explored knowledge about long-term risks after HDP. Distribution occurred from February to July 2019 via professional colleges, key organisations and social media. The objective was to assess current knowledge and knowledge gaps amongst a group of healthcare providers (HCP) in Australia, regarding long-term cardiovascular health after hypertensive disorders of pregnancy (HDP), specifically gestational hypertension or preeclampsia. RESULTS:Of 492 respondents, 203 were midwives, 188 obstetricians, 75 general practitioners (GP), and 26 cardiologists. A risk knowledge score was computed with 0-6 considered low, 6.1-8.9 moderate and 9-12 high. Most participants (85%) were aware of increased cardiovascular disease after preeclampsia and gestational hypertension (range 76% midwives to 100% cardiologists). There were significant differences in average knowledge scores regarding health after preeclampsia; high for cardiologists (9.3), moderate for GPs and obstetricians (8.2 and 7.6 respectively) and low for midwives (5.9). Average knowledge scores were somewhat lower for gestational hypertension (9.0 for cardiologists, 7.4 for obstetricians and GPs, 5.1 for midwives). Knowledge was highest regarding risk of chronic hypertension, moderate to high regarding risk of ischaemic heart disease, stroke and recurring HDP, and low for diabetes and peripheral vascular disease. Only 34% were aware that risks start < 10 years after the affected pregnancy. CONCLUSION(S):Participants were aware there is increased cardiovascular risk after HDP, although less aware of risks after gestational hypertension and some specific risks including diabetes. Findings will inform the development of targeted education
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