173 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 0.5ÎŒm 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 ÎŒA 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
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 3,680Â m, that continually collect and transmit measurements of soil moisture at three depths (5, 20, and 50Â cm), soil temperature (20Â cm), and meteorological conditions. Timeâlapse cameras for phenological observations, snow depth sensors, and periodic coâlocated vegetation surveys complement selected stations. iRON was conceived and designed with the joint purpose of supporting bioclimatic research and resource management objectives in a snowâdominated 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 climateâdriven changes to soil, vegetation, and hydrologic conditions. In presenting this network and its initial data, we hope that the networkâs elevational gradient will contribute to bioclimatic mountain research, while active collaboration with partners in resource management may provide a model for scienceâpractice interaction in support of longâterm 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, inâground soilâmoisture 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 1,800âm 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 networkâs 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 1,800âm 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 closer, the better? Untangling scientist-practitioner engagement, interaction, and knowledge use
Separate processing of texture and form in the ventral stream : evidence from fMRI and visual agnosia.
Real-life visual object recognition requires the processing of more than just geometric (shape, size, and orientation) properties. Surface properties such as color and texture are equally important, particularly for providing information about the material properties of objects. Recent neuroimaging research suggests that geometric and surface properties are dealt with separately, within the lateral occipital cortex (LOC) and the collateral sulcus (CoS), respectively. Here we compared objects that either differed in aspect ratio or in surface texture only, keeping all other visual properties constant. Results on brain-intact participants confirmed that surface texture activates an area in the posterior CoS, quite distinct from the area activated by shape within LOC. We also tested two patients with visual object agnosia, one of whom (DF) performed well on the texture task but at chance on the shape task, while the other (MS) showed the converse pattern. This behavioral double dissociation was matched by a parallel neuroimaging dissociation, with activation in CoS but not LOC in patient DF, and activation in LOC but not CoS in patient MS. These data provide presumptive evidence that the areas respectively activated by shape and texture play a causally necessary role in the perceptual discrimination of these features
Patterns of emergency admission for IBD patients over the last 10 years in Lothian, Scotland: A retrospective prevalent cohort analysis
OBJECTIVE: It is unclear how the compounding prevalence of inflammatory bowel disease (IBD) has translated into the causes and rates of hospitalisation, particularly in an era of increased biologic prescribing. We aimed to analyse these trends in a population-based IBD cohort over the last 10 years. DESIGN: The Lothian IBD registry is a complete, validated, prevalent database of IBD patients in NHS Lothian, Scotland. ICD-10 coding of hospital discharge letters from all IBD patient admissions to secondary care between 1 January 2010 and 31 December 2019 was interrogated for admission cause, with linkage to local/national data sets on death and prescribed drugs. RESULTS: Fifty-seven per cent (4673/8211) of all IBD patients were admitted to secondary care for >24 h between 1 January 2010 and 31 December 2019. In patients 60 years (19% of admissions). Three per cent (243/8211) of IBD patients accounted for 50% of the total IBD bed-days over the study period. Age-standardised IBD admission rates fell from 39.4 to 25.5 admissions per 100,000 population between 2010 and 2019, an average annual percentage reduction of 3% (95% CI -4.5% to -2.1%, p < 0.0001). Non-IBD admission rates were unchanged overall (145-137 per 100,000 population) and specifically for serious (hospitalisation) and severe (ITU admission or death) infection over the same period. CONCLUSION: Despite compounding prevalence and increased biologic use, IBD admission rates are falling. The cause of admission varies with age, with infection the predominant cause in older patients
Tiered Approach to Resilience Assessment
Regulatory agencies have long adopted a three-tier framework for risk assessment. We build on this structure to propose a tiered approach for resilience assessment that can be integrated into the existing regulatory processes. Comprehensive approaches to assessing resilience at appropriate and operational scales, reconciling analytical complexity as needed with stakeholder needs and resources available, and ultimately creating actionable recommendations to enhance resilience are still lacking. Our proposed framework consists of tiers by which analysts can select resilience assessment and decision support tools to inform associated management actions relative to the scope and urgency of the risk and the capacity of resource managers to improve system resilience. The resilience management framework proposed is not intended to supplant either risk management or the many existing efforts of resilience quantification method development, but instead provide a guide to selecting tools that are appropriate for the given analytic need. The goal of this tiered approach is to intentionally parallel the tiered approach used in regulatory contexts so that resilience assessment might be more easily and quickly integrated into existing structures and with existing policies
Trust in financial services: the influence of demographics and dispositional characteristics
So far, very little attention has been paid to examining consumer perceptions of trust from an interdisciplinary perspective. The purpose of this study is to examine how consumer trusting belief and disposition to trust within the financial services sector vary on the basis of individual demographic differences in trust. The research provides new insights into how consumers with higher dispositional trust have higher institutional trust and higher trusting belief and how consumersâ trusting belief significantly differs according to their demographic background in terms of age, marital status, ethnicity and gross annual income. The findings offer useful insights for the managers in financial institutions to carefully consider the impact of the influence of these individual differences on consumer behaviour in order to serve the needs of consumers in their target market and be able to design financial products and develop trust building strategies to attract and retain them. They also call for the action of the regulators and the financial institutions to play their part in building strong institutional systems that contribute to engendering higher levels of consumer trust
Sortase-Modified Cholera Toxoids Show Specific Golgi Localization
Cholera toxoid is an established tool for use in cellular tracing in neuroscience and cell biology. We use a sortase labeling approach to generate site-specific N-terminally modified variants of both the A2-B5 heterohexamer and B5 pentamer forms of the toxoid. Both forms of the toxoid are endocytosed by GM1-positive mammalian cells, and while the heterohexameric toxoid was principally localized in the ER, the B5 pentamer showed an unexpectedly specific localization in the medial/trans-Golgi. This study suggests a future role for specifically labeled cholera toxoids in live-cell imaging beyond their current applications in neuronal tracing and labeling of lipid rafts in fixed cells
- âŠ