Conservative Set Of Assumptions Research Articles

Overcoming unreported violence using place‐based ambulance data: The case for mapping hotspots based on health data for crime prevention initiatives

AbstractA key concern in crime analysis is the “hidden crime” problem. Crime events unaccounted for in police records limit the external validity of official statistics and, more importantly, hinder the ability of the police to manage crime and utilize their resources effectively. The problem is exacerbated in proactive initiatives aimed at curbing violence through hotspot policing, where inaccuracies and imprecision, or, worse, no data at all, diminish prevention efforts. Previous studies have sought to overcome the data problem by juxtaposing police records with ambulance data on assault callouts and have found profound disparities. Specifically, researchers matched “crime hotspots” with “ambulance hotspots” (rather than individual events) because patient confidentiality considerations have prevented health professionals from sharing subject‐level data with the police. However, health services can safely share spatial data on wider areas that do not disclose personal information. We build on this line of inquiry by analyzing data from the Thames Valley, United Kingdom, and observing spatial hotspots of different sizes. The results demonstrate that while the police and ambulance services attend to the same communities and similar types of facilities, the police are “blinded” to the location of nearly 8 out of 10 assaults. The incongruency is shown even with severe assaults, but to a lesser extent. We then simulate the reduction in injuries if the police had access to health data at different spatial levels and show that even under the most conservative set of assumptions, such an approach can prevent between 113 and 116 violent injuries each year that might otherwise require hospitalization.

Streamlined Approach to Identify Projects That Are Not of Air Quality Concern for PM10 Hot-Spot Analysis

Project-level particulate matter (PM) analysis, also known as hot-spot analysis, is required in non-attainment and maintenance areas for transportation projects that are identified as projects of air quality concern (POAQC). The only PM non-attainment area in Texas is El Paso which is currently designated as non-attainment for PM10. This paper presents an analytical methodology that was developed to determine the thresholds for highway activity parameters that would streamline the identification of projects that are not POAQCs, and minimize the risk that the project is misclassified. Researchers used the example provided by EPA, that is, 125,000 annual average daily traffic (AADT) and 8% heavy-duty trucks, as the baseline for the analysis. They then established combinations of AADT and truck percentage that would result in the same amount of PM10 emissions as the baseline scenario. Researchers used a set of conservative assumptions to achieve a very conservative/low-risk determination. The most important assumption among them was to not use a fixed baseline analysis year. Researchers used the proposed methodology to establish traffic activity thresholds for highway projects in El Paso, TX. Researchers established a baseline traffic activity (AADT and truck percentage) threshold curve which is a conservative representative of the lower boundary of POAQCs. Any combination of truck percentage and AADT that falls below this curve can be confidently excluded from POAQC consideration. Researchers developed an easy-to-use spreadsheet tool that would use user-provided AADT and truck percentages to identify whether a project could be confidently classified as not of air quality concern.

Modelling the incidence and mortality of psychotic disorders: Data from the second Australian national survey of psychosis

The aim of this study was to model estimates related to (a) the incidence of psychotic disorders and (b) the mortality associated with these disorders based on a large, population-based prevalence study. Data were drawn from the second national survey of adults with psychotic disorders conducted in seven Australian catchment areas during March to December 2010. To generate incidence rate estimates, we identified recent onset cases recruited as part of the prevalence study and then imputed population-based incidence rates using a set of conservative assumptions. Similarly, for mortality rates, we identified individuals who had died after being identified as 'screen-positive' for psychosis, but prior to full clinical assessment. Using a set of conservative assumptions, we then used these estimates to infer population-based mortality rates. Based on our models, we estimated that the incidence rate for psychotic disorders was 28 cases per 100,000 population. The rate estimates were significantly higher in males than females, with an overall male:female ratio of 1.57:1. Incidence rate estimates peaked in the youngest age group (18-24 years). The adjusted mortality rate estimated during the whole period of observation was 12.5 per 1000 persons, with a standardised mortality ratio of 5.5. Using treated prevalence data and observed deaths with appropriate algorithms, we were able to impute incidence and mortality rates for psychotic disorders consistent with the published literature. While the second national survey of psychotic disorders was not designed to identify mortality, our estimates provide a stark reminder of the increased mortality associated with these disorders.

Inherent possibilities and limitations of finite element modelling of defective girth welds

Welds unavoidably show defects, which can negatively affect the integrity of the entire structureand, worst case, result in a failure. Defects of a considerable size should therefore be detected, assessedand, if necessary, repaired. The assessment of a defect requires a procedure which allows a conservativeestimation of the acceptability of the defect. To develop such procedure, both experimental and numericalresearch is performed. This paper describes the inherent possibilities and limitations of numerical researchthrough finite element modelling, as compared to experimental research. Summarizing all arguments, itbecomes clear that numerical research is a highly powerful tool, but a thorough experimental validation is ofparamount importance. Moreover, some specific weld-related problems are highly difficult to address,namely the presence of stable crack growth and material heterogeneity. More research is needed toachieve a description of these phenomena, under a set of conservative assumptions.

Determination of Ensemble-Average Pairwise Root Mean-Square Deviation from Experimental B-Factors

Root mean-square deviation (RMSD) after roto-translational least-squares fitting is a measure of global structural similarity of macromolecules used commonly. On the other hand, experimental x-ray B-factors are used frequently to study local structural heterogeneity and dynamics in macromolecules by providing direct information about root mean-square fluctuations (RMSF) that can also be calculated from molecular dynamics simulations. We provide a mathematical derivation showing that, given a set of conservative assumptions, a root mean-square ensemble-average of an all-against-all distribution of pairwise RMSD for a single molecular species, <RMSD2>1/2, is directly related to average B-factors (<B>) and <RMSF2>1/2. We show this relationship and explore its limits of validity on a heterogeneous ensemble of structures taken from molecular dynamics simulations of villin headpiece generated using distributed-computing techniques and the Folding@Home cluster. Our results provide a basis for quantifying global structural diversity of macromolecules in crystals directly from x-ray experiments, and we show this on a large set of structures taken from the Protein Data Bank. In particular, we show that the ensemble-average pairwise backbone RMSD for a microscopic ensemble underlying a typical protein x-ray structure is ∼1.1 Å, under the assumption that the principal contribution to experimental B-factors is conformational variability.

Probing the Coevolution of Supermassive Black Holes and Quasar Host Galaxies

At low redshift, there are fundamental correlations between the mass of supermassive black holes (BH) and the mass (bulge) and luminosity of the host galaxy bulge. We investigate the same relation at z 1. Using virial mass estimates for 11 quasars at z 2 to measure their black hole mass, we find that black holes at high z fall nearly on the same BH versus R-band magnitude (MR) relation (to ~0.3 mag) as low-redshift active and inactive galaxies, without making any correction for luminosity evolution. Using a set of conservative assumptions about the host galaxy stellar population, we show that at z 2 (10 Gyr ago), the ratio of BH/bulge was 3-6 times larger than today. Barring unknown systematic errors on the measurement of BH, we also rule out scenarios in which moderately luminous quasar hosts at z 2 were fully formed bulges that passively faded to the present epoch. On the other hand, five quasar hosts at z ≈ 1 are consistent with the current-day BH-MR relationship after taking into account evolution that is appropriate for E/S0 galaxies. Therefore, z ≈ 1 host galaxies appear to fit the hypothesis that they are fully formed early-type galaxies. We also find that most quasar hosts with absolute magnitudes brighter than MR = -23 cannot fade below L* galaxies today, regardless of their stellar population makeup, because their black hole masses are too high and they must arrive at the local BH-MR relationship by z = 0.

Short-term improvements in public health from global-climate policies on fossil-fuel combustion: an interim report

Summary Background Most public-health assessments of climate-control policies have focused on long-term impacts of global change. Our interdisciplinary working group assesses likely short-term impacts on public health. Methods We combined models of energy consumption, carbon emissions, and associated atmospheric particulate-matter (PM) concentration under two different forecasts: business-as-usual (BAU); and a hypothetical climate-policy scenario, where developed and developing countries undertake significant reductions in carbon emissions. Findings We predict that by 2020, 700 000 avoidable deaths (90% CI 385000–1034000) will occur annually as a result of additional PM exposure under the BAU forecasts when compared with the climate-policy scenario. From 2000 to 2020, the cumulative impact on public health related to the difference in PM exposure could total 8 million deaths globally (90% CI 4.4–11.9 million). In the USA alone, the avoidable number of annual deaths from PM exposure in 2020 (without climate-change-control policy) would equal in magnitude deaths associated with human immunodeficiency diseases or all liver diseases in 1995. Interpretation The mortality estimates are indicative of the magnitude of the likely health benefits of the climate-policy scenario examined and are not precise predictions of avoidable death. While characterised by considerable uncertainty, the short-term public-health impacts of reduced PM exposures associated with greenhouse-gas reductions are likely to be substantial even under the most conservative set of assumptions.

The Possible Role of Indoor Radon Reduction Systems in Back-Drafting Residential Combustion Appliances

Abstract A computational sensitivity analysis was conducted to identify the conditions under which residential active soil depressurization (ASD) systems for indoor radon reduction might most likely exacerbate or create back-drafting of natural-draft combustion appliances. Parameters varied included: house size; normalized leakage area; exhaust rate of exhaust appliances other than the ASD system; and the amount of house air exhausted by the ASD system. Even with a reasonably conservative set of assumptions, it is predicted that ASD systems should not exacerbate or create back- drafting in most of the U.S. housing stock. Only at normalized leakage areas lower than 3 to 4 cm2 (@ 4 Pa) per m2 of floor area should ASD contribute to back-drafting, even in small houses at high ASD exhaust rates (compared to a mean of over 10 cm2/m2 determined from data on over 12,000 U.S. houses). But on the other hand, even with a more forgiving set of assumptions, it is predicted that ASD systems could contribute to back-drafting in some fraction of the housing stock – houses tighter than about 1 to 2 cm2/m2– even in large houses at minimal ASD exhaust rates. It is not possible to use parameters such as house size or ASD system flow rate to estimate reliably the risk that an ASD system might contribute to back-drafting in a given house. Spillage/back-draft testing would be needed for essentially all installations.

Medical radiation exposure and genetic risks.

Everyone is exposed to background radiation throughout life (100 mrem/year to the gonads or 4 to 5 rem during the reproductive years). A lumbosacral series might deliver 2,500 mrem to the male or 400 mrem to the female gonads. A radiologic procedure is a cost/benefit decision, and genetic risk is a part of the cost. Although cost is usually very low compared to benefit, if the procedure is unnecessary then the cost may be unacceptable. On the basis of current estimates, the doubling dose is assumed to be 40 rem (range 20 to 200) for an acute dose, and 100 rem for protracted exposure. Although there is no satisfactory way to predict the size of the risk for an individual exposed, any risk should be incentive to avoid unnecessary radiation to the gonads. Conception should be delayed for at least ten months for women and three or four months for men after irradiation of the gonads. The current incidence of genetically related diseases in the United States population is 60,000 per million live births. Based on the most conservative set of assumptions, an average gonadal dose of 1,000 mrem to the whole population would increase the incidence of genetically related diseases by 0.2%.