999 resultados para secondary air
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R commands to calculate the secondary production estimates using the size-frequency method after Hynes and Coleman (1968), Benke (1979) and Huryn (1996).
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A simple method determining airborne monoethanolamine has been developed. Monoethanolamine determination has traditionally been difficult due to analytical separation problems. Even in recent sophisticated methods, this difficulty remains as the major issue often resulting in time-consuming sample preparations. Impregnated glass fiber filters were used for sampling. Desorption of monoethanolamine was followed by capillary GC analysis and nitrogen phosphorous selective detection. Separation was achieved using a specific column for monoethanolamines (35% diphenyl and 65% dimethyl polysiloxane). The internal standard was quinoline. Derivatization steps were not needed. The calibration range was 0.5-80 μg/mL with a good correlation (R(2) = 0.996). Averaged overall precisions and accuracies were 4.8% and -7.8% for intraday (n = 30), and 10.5% and -5.9% for interday (n = 72). Mean recovery from spiked filters was 92.8% for the intraday variation, and 94.1% for the interday variation. Monoethanolamine on stored spiked filters was stable for at least 4 weeks at 5°C. This newly developed method was used among professional cleaners and air concentrations (n = 4) were 0.42 and 0.17 mg/m(3) for personal and 0.23 and 0.43 mg/m(3) for stationary measurements. The monoethanolamine air concentration method described here was simple, sensitive, and convenient both in terms of sampling and analytical analysis.
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Senate File 2355 Sec. 19 (Iowa Code §328.13) created a commercial air service retention and expansion committee within the aviation office of the department of transportation. The membership of the committee consisted of the director or the director’s designee; the managers of each airport in Iowa with commercial air service; two members of the senate, one appointed by the majority leader of the senate and one appointed by the minority leader of the senate; and two members of the house of representatives, one appointed by the speaker of the house and one appointed by the minority leader of the house. The committee was to develop a plan by December 31, 2014 for the retention and expansion of passenger air service in Iowa. The committee is to meet as the committee deems necessary to assess progress in implementing the plan and, if necessary, to update the plan.
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INTRODUCTION: We sought to study the operational and medical aspects of helicopter rescue missions involving the use of a winch.¦SETTING: A single helicopter-based medical service of a pre-alpine region of Switzerland.¦METHODS: We prospectively studied consecutive primary rescue interventions involving winching of a physician, from October 1, 1998 to October 1, 2002. Demographic, medical and operational aspects as well as outcome at 48 hours were analyzed.¦RESULTS: We included 133 patients. Most (74%) were male, with traumatic injuries (77%). The median scene time of the nine severely injured patients (Injury Severity Scale [ISS] > 15) was significantly longer compared with the other patients (54 vs 37 minutes; P < .05). The main medical procedures performed were orotracheal intubation (n = 5), fracture reductions (n = 5), major analgesia with sedation (n = 4), and intravenous fluid administration of more than 1,500 mL (n = 4). Fourteen (10%) patients suffering from minor injuries were triaged by the physician and not airlifted to the hospital. All 133 patients were alive at 48 hours. Sixty-nine (52%) were still hospitalized. No secondary interhospital transfer was required.¦CONCLUSION: Our study provides a better knowledge of injury profile, medical aspects, and outcomes of patients rescued necessitating a winching procedure.
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Hypothenar hammer syndrome is an uncommonly encountered cause of Raynaud's phenomenon associated with professional or recreational activities. We report 6 consecutive cases seen in our angiology unit between 1988 and 1990. Clinical findings include a history of repeated microtraumatisms of the dominant hand, male sex, unilaterality, sudden onset, and severe Raynaud's phenomenon of the last three fingers. Investigations reveal an aneurysm or thrombosis of the distal cubital artery or of the superficial palmar branch, associated with occlusion of digital arteries. Avoidance of the aggravating conditions or resection and/or plasty of the affected vascular segment usually leads to disappearance of the symptoms.
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Cooperation is ubiquitous in nature: genes cooperate in genomes, cells in muti- cellular organims, and individuals in societies. In humans, division of labor and trade are key elements of most known societies, where social life is regulated by- moral systems specifying rights and duties often enforced by third party punish¬ment. Over the last decades, several primary mechanisms, such as kin selection, direct and indirect reciprocity, have been advanced to explain the evolution of cooperation from a naturalistic approach. In this thesis, I focus on the study of three secondary mechanisms which, although insufficient to allow for the evo¬lution of cooperation, have been hypothesized to further promote it when they are linked to proper primary mechanisms: conformity (the tendency to imitate common behaviors), upstream reciprocity (the tendency to help somebody once help has been received from somebody else) and social diversity (heterogeneous social contexts). I make use of mathematical and computational models in the formal framework of evolutionary game theory in order to investigate the theoret¬ical conditions under which conformity, upstream reciprocity and social diversity are able to raise the levels of cooperation attained in evolving populations. - La coopération est ubiquitaire dans la nature: les gènes coopèrent dans les génomes, les cellules dans les organismes muticellulaires, et les organismes dans les sociétés. Chez les humains, la division du travail et le commerce sont des éléments centraux de la plupart des sociétés connues, où la vie sociale est régie par des systèmes moraux établissant des droits et des devoirs, souvent renforcés par la punition. Au cours des dernières décennies, plusieurs mécanismes pri¬maires, tels que la sélection de parentèle et les réciprocités directe et indirecte, ont été avancés pour expliquer l'évolution de la coopération d'un point de vue nat¬uraliste. Dans cette thèse, nous nous concentrons sur l'étude de trois mécanismes secondaires qui, bien qu'insuffisants pour permettre l'évolution de la coopération, sont capables de la promouvoir davantage s'ils sont liés aux mécanismes primaires appropriés: la conformité (tendance à imiter des comportements en commun), la 'réciprocité en amont' (tendance à aider quelqu'un après avoir reçu l'aide de quelqu'un d'autre) et la diversité sociale (contextes sociaux hétérogènes). Nous faisons usage de modèles mathématiques et informatiques dans le cadre formel de la théorie des jeux évolutionnaires afin d'examiner les conditions théoriques dans lesquelles la conformité, la 'réciprocité en amont' et la diversité sociale sont capables d'élever le niveau de coopération des populations en évolution.
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BACKGROUND: Secondary prevention programs for patients experiencing an acute coronary syndrome have been shown to be effective in the outpatient setting. The efficacy of in-hospital prevention interventions administered soon after acute cardiac events is unclear. We performed a systematic review and meta-analysis to determine whether in-hospital, patient-level interventions targeting multiple cardiovascular risk factors reduce all-cause mortality after an acute coronary syndrome. METHODS AND RESULTS: Using a prespecified search strategy, we included controlled clinical trials and before-after studies of secondary prevention interventions with at least a patient-level component (ie, education, counseling, or patient-specific order sets) initiated in hospital with outcomes of mortality, readmission, or reinfarction rates in acute coronary syndrome patients. We classified the interventions as patient-level interventions with or without associated healthcare provider-level interventions and/or system-level interventions. Twenty-six studies met our inclusion criteria. The summary estimate of 14 studies revealed a relative risk of all-cause mortality of 0.79 (95% CI, 0.69 to 0.92; n=37,585) at 1 year. However, the apparent benefit depended on study design and level of intervention. The before-after studies suggested reduced mortality (relative risk [RR], 0.77; 95% CI, 0.66 to 0.90; n=3680 deaths), whereas the RR was 0.96 (95% CI, 0.64 to 1.44; n=99 deaths) among the controlled clinical trials. Only interventions including a provider- or system-level intervention suggested reduced mortality compared with patient-level-only interventions. CONCLUSIONS: The evidence for in-hospital, patient-level interventions for secondary prevention is promising but not definitive because only before-after studies suggest a significant reduction in mortality. Future research should formally test which components of interventions provide the greatest benefit.
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The stability of air bubbles in fresh concrete can have a profound influence of the potential durability of the system, because excessive losses during placement and consolidation can compromise the ability of the mixture to resist freezing and thawing. The stability of air void systems developed by some air entraining admixtures (AEAs) could be affected by the presence of some polycarboxylate-based water reducing admixtures (WRAs). The foam drainage test provides a means of measuring the potential stability of air bubbles in a paste. A barrier to acceptance of the test was that there was little investigation of the correlation with field performance. The work reported here was a limited exercise seeking to observe the stability of a range of currently available AEA/WRA combinations in the foam drainage test; then, to take the best and the worst and observe their stabilities on concrete mixtures in the lab. Based on the data collected, the foam drainage test appears to identify stable combinations of AEA and WRA.
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If adequately designed and high quality material and good construction practices are used, portland cement concrete is very durable. This is demonstrated by the oldest pavement in Iowa (second oldest in the U.S.) paved in 1904, which performed well for 70 years without resurfacing. The design thickness is an important factor in both the performance and cost of pavement. The objective of this paper is to provide a 30-year performance evaluation of a pavement constructed to determine the required design thickness for low volume secondary roadways. In 1951 Greene County and the Iowa Highway Research Board of the Iowa Department of Transportation initiated a four-mile (6.4 km) demonstration project to evaluate thicknesses ranging from 4-1/2" (11.4 cm) to 6" (15.2 cm). The project, consisting of 10 research sections, was formed pavement placed on a gravel roadbed with very little preparation except for redistribution of the loose aggregate. Eight sections were non-reinforced except for centerline tie bars and no contraction joints were used. Mesh reinforcing and contraction joints spaced at 29' 7" (9.02 m) intervals were used in two 4-1/2" (11.4 cm) thick sections. The only air entrained section was non-reinforced. The pavement performed well over its 30-year life carrying a light volume of traffic and did not require major maintenance. There was substantial cracking with average slab length varying directly with thickness. The 4-1/2" (11.4 cm) thick non-air entrained, mesh-reinforced pavement with contraction joints has performed the best.
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The State of Iowa has too many roads. Although ranking thirty-fourth in population, twenty-fifth in area, and twentieth in motor vehicle registration, it ranks seventh in the nation in miles of rural roads. In 1920 when Iowa's rural population was 1,528,000, there were 97,440 miles of secondary roads. In 1960 with rural population down 56 percent to 662,000, there were 91,000 miles of secondary roads--a 7 percent decrease. The question has been asked: "Who are these 'service roads' serving?" This excess mileage tends to dissipate road funds at a critical time of increasing public demand for better and safer roads.
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Major highway concrete pavements in Iowa have exhibited premature deterioration attributed to effects of ettringite formation, alkali-silica expansive reactions, and to frost attack, or some combination of them. These pavements were constructed in the mid- 1980s as non-reinforced, dual-lane, roads ranging in thickness between 200 mm and 300 mm, with skewed joints reinforced with dowels. Deterioration was initially recognized with a darkening of joint regions, which occurred for some pavements as soon as four years after construction. Pavement condition ranges from severe damage to none, and there appeared to be no unequivocal materials or processing variables correlated with failure. Based upon visual examinations, petrographic evaluation, and application of materials models, the deterioration of concrete highway pavements in Iowa appear related to a freeze-thaw failure of the coarse aggregate and the mortar. Crack patterns sub-parallel to the concrete surface transecting the mortar fraction and the coarse aggregate are indicative of freeze-thaw damage of both the mortar and aggregate. The entrained air void system was marginal to substandard, and filling of some of the finer-sized voids by ettringite appears to have further degraded the air void system. The formation of secondary ettringite within the entrained air voids probably reflects a relatively high degree of concrete saturation causing the smaller voids to be filled with pore solution when the concrete freezes. Alkali-silica reaction (ASR) affects some quartz and shale in the fine aggregate, but is not considered to be a significant cause of the deterioration. Delayed ettringite formation was not deemed likely as no evidence of a uniform paste expansion was observed. The lack of field-observed expansion is also evidence against the ASR and DEF modes of deterioration. The utilization of fly ash does not appear to have affected the deterioration as all pavements with or without fly ash exhibiting substantial damage also exhibit significant filling of the entrained air void system, and specimens containing fly ash from sound pavements do not have significant filling. The influence of the mixture design, mixing, and placing must be evaluated with respect to development of an adequate entrained air void system, concrete homogeneity, longterm drying shrinkage, and microcracking. A high-sand mix may have contributed to the difficult mixture characteristics noted upon placement and exacerbate concrete heterogeneity problems, difficulty in developing an adequate entrained air void system, poor consolidation potential, and increased drying shrinkage and cracking. Finally, the availability of moisture must also be considered, as the secondary precipitation of ettringite in entrained air voids indicates they were at least partially filled with pore solution at times. Water availability at the base of the slabs, in joints, and cracks may have provided a means for absorbing water to a point of critical saturation.
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Portland cement concrete pavements have given excellent service history for Iowa. Many of these pavements placed during the 1920’s and 1930’s are still in service today. Many factors go in to achieve a long term durable concrete pavement. Probably the most important is the durability of the aggregate. Until the 1930’s, pit run gravel was the most predominant aggregate used. Many of these gravels provided long term performance and their durability is dependent upon the carbonate fraction of the gravel. Later, limestone (calcium carbonate) and dolomite (calcium, magnesium carbonate) sources were mined across Iowa. The durability of these carbonate aggregates is largely dependent upon the pore system which can cause freeze thaw problems known as D-cracking, which was a problem with some sources during the 1960’s. Also, some of these carbonate aggregates are also susceptible to deterioration from deicing salts. Geologists have identified the major components that affect the durability of these carbonate aggregates and sources are tested to ensure long term performance in Portland cement concrete. Air entrainment was originally put in concrete to improve scaling resistance. It is well known that air entrainment is required to provide freeze thaw protection in concrete pavements today. In Iowa, air entrainment was not introduced in concrete pavements until 1952. This research investigates properties that made older concrete pavements durable without air entrainment.
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Plastic air content is typically tested by the pressure method, ASTM C138. Loss of air content through the paver has been shown to exceed 2 percent at times. Research has shown that early deterioration of pavements in Iowa may be directly or indirectly related to low or inadequate air content. Hardened air content is typically checked using the linear traverse method, ASTM C457. The linear traverse method is very time consuming and could not be used on a production scale. A quick and effective method of testing in place air content is needed. Research has shown a high degree of correlation with the high-pressure method of determining air content of hardened concrete versus plastic air content in laboratory conditions. This research indicated that air contents are more variable when comparing core results to plastic air content, although the overall average for the air content was comparable. Perhaps, the location of the plastic air content test, obtained from construction records, versus location of the cores was not as accurate as needed.