2,399 research outputs found
A Deep Multicolor Survey I. Imaging Observations and Catalog of Stellar Objects
We have used the KPNO 4-meter Mayall telescope to image 0.83 square degrees
of sky in six fields at high galactic latitude in six filters spanning
3000-10000\AA\ to magnitude limits ranging from 22.1 to 23.8. We have assembled
a catalog of 21,375 stellar objects detected in the fields for use primarily in
conducting a multicolor search for quasars. This paper describes the data
reduction techniques used on the CCD data, the methods used to construct the
stellar object catalog, and the simulations performed to understand its
completeness and contamination.Comment: To Appear in ApJ Supplement, 1996. 168k uuencoded gunzipped tarred
tex file (requires aas2pp4.sty and tighten.sty) and 4 PostScript figures.
Also available at http://astro.as.arizona.edu/~pathall/astro.html#preprint
Geometric Design, Speed, and Safety
In this seminar, Dr. Porter will explore the interactions of geometric design decisions, speed, and safety. A performance-based approach to this topic will be considered given the availability of several key documents, including the Highway Safety Manual and TRB\u27s Modeling Operating Speed: Synthesis Report as well as a significant body of published research. A historical look at the design speed concept will show that while the design speed definition has changed on more than one occasion, the same basic but flawed philosophy that relates design speed to a âsafe speedâ is still reflected in supplemental guidance related to design speed selection in current design policy. A conservative approach to establishing design criteria, currently used to address the range of driver, vehicle, and roadway conditions and capabilities that a designer must consider, will be demonstrated. Resulting operating speeds will be shown to be higher than design speeds for design speeds of approximately 55 mph or less. This outcome may be considered undesirable from a safety perspective, but that categorization seems to be based more on subjective judgments of desirability than on actual safety findings. The outcome does, however, present significant challenges to a context-sensitive design approach. Finally, the idea of speed management through the use of roadway geometrics (i.e., geometric designs that influence driver selection of operating speed), one component of self-enforcing, self-explaining roadway design, will be explored. Findings will uncover possible challenges to implementing this idea.
Five related questions will then be investigated:
1) What is known about the relationships between road geometry and operating speeds?
2) To what degree does road geometry influence operating speeds?
3) How are safety and security influenced by road geometry?
4) What are the potential impacts to large vehicles?
5) What is the nature of the speed-safety trade-off? Possible alternatives for achieving desired speed and safety outcomes will be offered to conclude the seminar.https://pdxscholar.library.pdx.edu/trec_seminar/1068/thumbnail.jp
Commercial Driver Medical Exams: Relationships Between Body Mass Index and Comorbid Conditions
There are an estimated 5.7 million Commercial Motor Vehicle (CMV) drivers in the United States in 2012. Health and Safety of CMV drivers are of high consequence group because of: occupational risks from the size and speed of their vehicles, frequently poor health status, poor health care utilization, and the large impact of truck crashes on public health and safety. CMV drivers pass a commercial driver medical examination (CDME) to maintain licensure. CDME examiners document multiple potentially disqualifying health conditions. CMV drivers reportedly have poor health status, which may be attributed to lifestyle and occupational factors (e.g., improper diet, inadequate physical activity, poor sleep hygiene, shift work), yet few data are reported analyzing relative importance and relationships of these factors. Methods- CDMEs conducted between 2005 and 2012 among 88,246 commercial drivers were analyzed. Associations between measured Body Mass Index (BMI) categories and CDME findings, as well as driver certification were examined. Results- 53.3% of drivers were obese (BMI\u3e30.0 kg/m2 ) with half of those being morbidly obese (BMI\u3e35.0 kg/m2 ). After adjustment for age and gender, obese drivers were statistically significantly less likely to be certified for the full 2 year period and significantly more likely to report many factors including heart disease, hypertension, diabetes mellitus, nervous disorders, sleep disorders, and chronic low back pain (all p\u3c0.0001). ConclusionsBMI is related to many factors, some of which have been associated with increased crash risk. BMI screening may be a useful tool. Interventions for BMI reduction may have an impact on comorbidities
Anthropogenic nutrients and harmful algae in coastal waters
© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Environmental Management 146 (2014): 206-216, doi:10.1016/j.jenvman.2014.07.002.Harmful algal blooms (HABs) are thought to be increasing in coastal waters worldwide. Anthropogenic nutrient enrichment has been proposed as a principal causative factor of this increase through elevated inorganic and/or organic nutrient concentrations and modified nutrient ratios. We assess: 1) the level of understanding of the link between the amount, form and ratio of anthropogenic nutrients and HABs; 2) the evidence for a link between anthropogenically generated HABs and negative impacts on human health; and 3) the economic implications of anthropogenic nutrient/HAB interactions. We demonstrate that an anthropogenic nutrient-HAB link is far from universal, and where it has been demonstrated, it is most frequently associated with high biomass rather than low biomass (biotoxin producing) HABs. While organic nutrients have been shown to support the growth of a range of HAB species, insufficient evidence exists to clearly establish if these nutrients specifically promote the growth of harmful species in preference to benign ones, or if/how they influence toxicity of harmful species. We conclude that the role of anthropogenic nutrients in promoting HABs is site-specific, with hydrodynamic processes often determining whether blooms occur. We also find a lack of evidence of widespread significant adverse health impacts from anthropogenic nutrient-generated HABs, although this may be partly due to a lack of human/animal health and HAB monitoring. Detailed economic evaluation and cost/benefit analysis of the impact of anthropogenically generated HABs, or nutrient reduction schemes to alleviate them, is also frequently lacking.The work described here is based in part on a project âHarmful Algae, Nuisance Blooms and Anthropogenic Nutrient Enrichmentâ funded by the UK Department for Environment, Food and Rural Affairs (contract ME2208). In addition KD was supported by the FP7 project Asimuth and funding from the NERC Shelf Seas Biogeochemistry and PURE Associates programmes. PJH was supported by University Grants Council of Hong Kong AoE project (AoE/P-04/0401). PH and LEF were funded by the US National Science Foundation (NSF) Award 1009106; LEF was funded in part by the European Regional Development Fund and European Social Fund (University of Exeter, Truro, Cornwall, UK). GM was supported by a NERC PhD studentship
Attribute-level Neighbor Hierarchy Construction Using Evolved Pattern-based Knowledge Induction
Neighbor knowledge construction is the foundation for the development of cooperative query answering systems capable of searching for close match or approximate answers when exact match answers are not available. This paper presents a technique for developing neighbor hierarchies at the attribute level. The proposed technique is called the evolved Pattern-based Knowledge Induction (ePKI) technique and allows construction of neighbor hierarchies for nonunique attributes based upon confidences, popularities, and clustering correlations of inferential relationships among attribute values. The technique is applicable for both categorical and numerical (discrete and continuous) attribute values. Attribute value neighbor hierarchies generated by the ePKI technique allow a cooperative query answering system to search for approximate answers by relaxing each individual query condition separately. Consequently, users can search for approximate answers even when the exact match answers do not exist in the database (i.e., searching for existing similar parts as part of the implementation of the concepts of rapid prototyping). Several experiments were conducted to assess the performance of the ePKI in constructing attribute-level neighbor hierarchies. Results indicate that the ePKI technique produces accurate neighbor hierarchies when strong inferential relationships appear among data. © 2006 IEEE
Survival time and critical temperatures of various strains of Entamoeba histolytica
Six strains of Entamoeba histolytica and one strain of Entamoeba coli were subjected to different temperatures. The single strain of E. coli tested proved to be more resistant to the high temperatures and more susceptible to the low temperatures than all the E. histolytica strains under study. Individual strains of E. histolytica differed in the length of their survival time at varying temperatures.Interchanging the bacterial flora of some of the strains produced no significant changes in the survival times of the amebae except for one monobacterial strain which benefited by the increase in bacterial flora.The critical temperature of three strains of E. histolytica and one strain of E. coli was carefully investigated. There were marked differences in the critical temperature among all strains. However, interchanging the bacterial flora of the strains did not alter their critical temperature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32490/1/0000576.pd
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