1,242 research outputs found
Operation of a Radar Altimeter over the Greenland Ice Sheet
This thesis presents documentation for the Advanced Application Flight Experiment (AAFE) pulse compression radar altimeter and its role in the NASA Multisensor Airborne Altimetry Experiment over Greenland in 1993. The AAFE Altimeter is a Ku-band microwave radar which has demonstrated 14 centimeter range precision in operation over arctic ice. Recent repairs and improvements were required to make the Greenland missions possible. Transmitter, receiver and software modifications, as well as the integration of a GPS receiver are thoroughly documented. Procedures for installation, and operation of the radar are described. Finally, suggestions are made for further system improvements
Lidar cloud studies for FIRE and ECLIPS
Optical remote sensing measurements of cirrus cloud properties were collected by one airborne and four ground-based lidar systems over a 32 h period during this case study from the First ISCCP (International Satellite Cloud Climatology Program) Regional Experiment (FIRE) Intensive Field Observation (IFO) program. The lidar systems were variously equipped to collect linear depolarization, intrinsically calibrated backscatter, and Doppler velocity information. Data presented describe the temporal evolution and spatial distribution of cirrus clouds over an area encompassing southern and central Wisconsin. The cirrus cloud types include: dissipating subvisual and thin fibrous cirrus cloud bands, an isolated mesoscale uncinus complex (MUC), a large-scale deep cloud that developed into an organized cirrus structure within the lidar array, and a series of intensifying mesoscale cirrus cloud masses. Although the cirrus frequently developed in the vertical from particle fall-streaks emanating from generating regions at or near cloud tops, glaciating supercooled (-30 to -35 C) altocumulus clouds contributed to the production of ice mass at the base of the deep cirrus cloud, apparently even through riming, and other mechanisms involving evaporation, wave motions, and radiative effects are indicated. The generating regions ranged in scale from approximately 1.0 km cirrus uncinus cells, to organized MUC structures up to approximately 120 km across
Survival Analysis and Computer Simulations of Lethal and Contraceptive Management Strategies for Urban Deer
I monitored survival of 34 female white-tailed deer (Odocoileus virginianus) in Bloomington, Minnesota, from October 1996 to December 1999. Twenty deer died: nineteen were killed by vehicles, and one was killed in a deer-removal program conducted by an adjacent suburb. Summer survival was high and varied little over the 3 years of study (range = 0.93 to 0.95). Fall survival ranged from 0.84 to 1.00, and winter survival was generally high during the 3 years of study, except during a severe winter (range = 0.72 to 0.95). I calculated population growth rates (λ) from Leslie matrix projections, using these survival estimates and productivity data collected from road-killed female deer in the Twin Cities (Minneapolis-St. Paul, Minnesota, USA) metropolitan area. When winter survival was high (0.94), my model simulations indicated the Bloomington deer population increased by 21% when no deer management program was in place. When a low winter survival rate (0.72) was modeled, the population decreased by 7%, even when no deer management program was implemented. I modeled what impact contraception may have on population growth and concluded that treating \u3e50% of adult female deer was necessary to stabilize population growth, and treating all females was necessary to decrease population growth under high winter survival conditions. I concluded that removal programs are more effective than immunocontraception programs because survival contributes more to population growth rates in deer populations than fecundity. I recommend removing 20% and 40% of adult female deer in the population to cause the population to stabilize or to reduce deer numbers, respectively. I recommend managers collect deer–vehicle collision data because these data potentially represent the most accurate and easily-obtainable life history component of an urban deer herd
Home Manufacture of Drugs: An Online Investigation and a Toxicological Reality Check of Online Discussions on Drug Chemistry
Emerging trends in market dynamics and the use of new psychoactive substances are both a public health concern and a complex regulatory issue. One novel area of investigation is the availability of homemade opioids, amphetamines and dissociatives, and the potential fueling of interest in clandestine home manufacture of drugs via the Internet. We illustrate here how online communal folk pharmacology of homemade drugs on drug website forums may actually inform home manufacture practices or contribute to the reduction of harms associated with this practice. Discrepancies between online information around purification and making homemade drugs safer, and the synthesis of the same substances in a proper laboratory environment, exist. Moderation and shutdown of synthesis queries and discussions online are grounded in drug websites adhering to harm-reduction principles by facilitating discussions around purification of homemade drugs only. Drug discussion forums should consider reevaluating their policies on chemistry discussions in aiming to reach people who cannot or will not refrain from cooking their own drugs with credible information that may contribute to reductions in the harms associated with this practice. © 2017 Taylor & Francis Group, LL
Bullet Fragmentation and Lead Deposition in White-Tailed Deer and Domestic Sheep
In February 2008, a private physician in North Dakota radiographed hunterharvested venison and found that 60 of 100 packages contained metal fragments. This discovery had implications for public-funded venison donation programs, and it prompted several Midwest states to examine their programs. Approximately 500,000 deer hunters harvest \u3e200,000 deer annually in Minnesota, and the state has a donation program similar to North Dakota’s program. Therefore, we analyzed fragmentation patterns and lead deposition in carcasses of 8 white-tailed deer (Odocoileus virginianus) and 72 domestic sheep (Ovis aries). We fired 5 different bullet types from centerfire rifles, and we also fired projectiles from both a shotgun and a black-powder muzzleloader. Centerfire bullets, which are designed to expand quickly upon impacting the animal, left bullet fragments and lead deposits throughout the entire abdominal cavity of carcasses. We also used 2 types of centerfire bullets that were purportedly designed to resist fragmentation. One of these bullet types had fragmentation patterns and lead deposition rates similar to the rapid-expanding bullets; the other bullet type resisted fragmentation, and no lead was detected in muscle tissue that we sampled. Centerfire bullets made from copper resisted fragmentation, and of course did not deposit any lead in muscle tissues. Projectiles fired from the shotgun and black-powder muzzleloader did deposit lead into carcasses but did not fragment as much as bullets fired from centerfire rifles. Our study suggests that rinsing the abdominal cavity may spread the lead contaminant to other areas of the carcass, thereby worsening the contamination situation. We suggest that hunters who use centerfire rifles and are concerned about lead exposure should purchase a bullet type that resists fragmentation
Evaluating Competing Preferences of Hunters and Landowners for Management of Deer Populations
Most state wildlife agencies consider public input in the management of whitetailed deer (Odocoileus virginianus) populations. In 2013, we surveyed deer hunters (n = 3,600) and landowners (n = 4,604) in southwest Minnesota to gauge their preferences for managing deer. We hypothesized a priori that, irrespective of their perceived impacts of deer, hunters would prefer deer populations to be increased and landowners would prefer deer populations to be decreased. Our findings suggest that defining stakeholder groups according to primary associations with deer (i.e., farming and hunting) accurately categorized differences in tolerance levels for deer populations in our study area. Deer damage was considered relatively minor by landowners, yet, 51% of landowners wanted deer densities reduced. Although 59% of hunters were satisfied with the number of deer, 62% of hunters still wanted deer densities increased in the future. Almost two-thirds of hunters were not satisfied with the number or quality of bucks where they hunted, and an antler-point restriction was the only potential regulation supported by hunters to reduce harvest mortality rates of bucks. To enable managers to monitor trends in public satisfaction relative to the fundamental objectives of deer management in an area, we recommend conducting frequent surveys of primary stakeholders
The cryoEM structure of cytochrome bd from C. glutamicum provides novel insights into structural properties of actinobacterial terminal oxidases
Cytochromes bd are essential for microaerobic respiration of many prokaryotes including a number of human pathogens. These enzymes catalyze the reduction of molecular oxygen to water using quinols as electron donors. Their importance for prokaryotic survival and the absence of eukaryotic homologs make these enzyme ideal targets for antimicrobial drugs. Here, we determined the cryoEM structure of the menaquinol-oxidizing cytochrome bd-type oxygen reductase of the facultative anaerobic Actinobacterium Corynebacterium glutamicum at a resolution of 2.7 Ă…. The obtained structure adopts the signature pseudosymmetrical heterodimeric architecture of canonical cytochrome bd oxidases formed by the core subunits CydA and CydB. No accessory subunits were identified for this cytochrome bd homolog. The two b-type hemes and the oxygen binding heme d are organized in a triangular geometry with a protein environment around these redox cofactors similar to that of the closely related cytochrome bd from M. tuberculosis. We identified oxygen and a proton conducting channels emerging from the membrane space and the cytoplasm, respectively. Compared to the prototypical enzyme homolog from the E. coli, the most apparent difference is found in the location and size of the proton channel entry site. In canonical cytochrome bd oxidases quinol oxidation occurs at the highly flexible periplasmic Q-loop located in the loop region between TMHs six and seven. An alternative quinol-binding site near heme b595 was previously identified for cytochrome bd from M. tuberculosis. We discuss the relevance of the two quinol oxidation sites in actinobacterial bd-type oxidases and highlight important differences that may explain functional and electrochemical differences between C. glutamicum and M. tuberculosis. This study expands our current understanding of the structural diversity of actinobacterial and proteobacterial cytochrome bd oxygen reductases and provides deeper insights into the unique structural and functional properties of various cytochrome bd variants from different phylae
Visual and personalized quality of life assessment app for people with severe mental health problems:Qualitative evaluation
Background:Â QoL-ME is a digital visual personalized quality of life assessment app for people with severe mental health problems. Research reveals that e-mental health apps frequently suffer from low engagement and fall short of expectations regarding their impact on patients' daily lives. Studies often indicate that e-mental health apps ought to respect the needs and preferences of end users to achieve optimal user engagement. Objective:Â The aim of this study was to explore the experiences of users regarding the usability and functionality of QoL-ME and whether the app is actionable and beneficial for patients. Methods:Â End users (n=8) of QoL-ME contributed to semistructured interviews. An interview guide was used to direct the interviews. All interviews were audiorecorded and transcribed verbatim. Transcriptions were analyzed and coded thematically. Results:Â Analysis revealed 3 main themes: (1) benefit, (2) actionability, and (3) characteristics of the QoL-ME. The first theme reveals that the QoL-ME app was beneficial for the majority of respondents, primarily by prompting them to reflect on their quality of life. The current version is not yet actionable; the actionability of the QoL-ME app may be improved by enabling users to view their scores over time and by supplying practical advice for quality of life improvements. Overall, participants had positive experiences with the usability, design, and content of the app. Conclusions:Â The QoL-ME app can be beneficial to users as it provides them with insight into their quality of life and elicits reflection. Incorporating more functionalities that facilitate self-management, such as advice and strategies for improving areas that are lacking, will likely make the app actionable. Patients positively regarded the usability, design, and contents of the QoL-ME app
Relevance of Interleukin-6 and D-Dimer for Serious Non-AIDS Morbidity and Death among HIV-Positive Adults on Suppressive Antiretroviral Therapy
Background:
Despite effective antiretroviral treatment (ART), HIV-positive individuals are at increased risk of serious non-AIDS conditions (cardiovascular, liver and renal disease, and cancers), perhaps due in part to ongoing inflammation and/or coagulation. To estimate the potential risk reduction in serious non-AIDS conditions or death from any cause that might be achieved with treatments that reduce inflammation and/or coagulation, we examined associations of interleukin-6 (IL-6), D-dimer, and high-sensitivity C-reactive protein (hsCRP) levels with serious non-AIDS conditions or death in 3 large cohorts.
Methods:
In HIV-positive adults on suppressive ART, associations of IL-6, D-dimer, and hsCRP levels at study entry with serious non-AIDS conditions or death were studied using Cox regression. Hazard ratios (HR) adjusted for age, gender, study, and regression dilution bias (due to within-person biomarker variability) were used to predict risk reductions in serious non-AIDS conditions or death associated with lower “usual” levels of IL-6 and D-dimer.
Results:
Over 4.9 years of mean follow-up, 260 of the 3766 participants experienced serious non-AIDS conditions or death. IL-6, D-dimer and hsCRP were each individually associated with risk of serious non-AIDS conditions or death, HR = 1.45 (95% CI: 1.30 to 1.63), 1.28 (95% CI: 1.14 to 1.44), and 1.17 (95% CI: 1.09 to 1.26) per 2x higher biomarker levels, respectively. In joint models, IL-6 and D-dimer were independently associated with serious non-AIDS conditions or death, with consistent results across the 3 cohorts and across serious non-AIDS event types. The association of IL-6 and D-dimer with serious non-AIDS conditions or death was graded and persisted throughout follow-up. For 25% lower “usual” IL-6 and D-dimer levels, the joint biomarker model estimates a 37% reduction (95% CI: 28 to 46%) in the risk of serious non-AIDS conditions or death if the relationship is causal.
Conclusions:
Both IL-6 and D-dimer are independently associated with serious non-AIDS conditions or death among HIV-positive adults with suppressed virus. This suggests that treatments that reduce IL-6 and D-dimer levels might substantially decrease morbidity and mortality in patients on suppressive ART. Clinical trials are needed to test this hypothesis
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