Study of factors associated with risk of work-related stairway falls

This report describes a study of stairway risk factors based on video tape recordings of workers using 31 flights of stairs selected from among the industries with the highest frequency and severity rates for stair-related injuries. The video tapes were reviewed to identify all incidents, i.e., falls, trips, slips, missteps, and moments of temporary instability. The characteristics of the 98 stair users who were involved in an incident were compared to the characteristics of a matched group of stair users who did not have incidents. The factors that best discriminated between the incident group and the nonincident group were: (a) The incident group tended to be those whose movement was impeded by others and who were older; and (b) The nonincident group tended to be those who were wearing glasses and those who were very large or heavy individuals. The influence of stairway physical features on the risk of injury was examined using correlation analysis. The measure of risk was the incidence rate (observed incidents per number of observed uses) for each flight as well as for each tread. Among the several variables significantly correlated with higher incidence rate are: (a) higher effective riser height and less effective tread depth; the safest stairs have an effective riser height not greater than 7 in. (18 cm) and an effective tread depth no less than 11 in. (27 cm); and (b) for descent only (92% of the injuries), the size of the nosing projection; it appears that nosing projections that exceed $\text{11}\text{16}$ in. (1.8 cm) are associated with higher incidence rates.     

不同来源腐殖酸的光解及过氧化氢对其影响

为探讨腐殖酸在环境中的行为及光解除去腐殖酸的可能性，利用大于２９０ｎｍ的模拟日光辐照，探讨了大骨节病病区、非病区腐殖酸和泥炭腐殖酸的光解过程和光解机理及过氧化氢对其光解的影响，发现随着光照时间的延长，腐殖酸水体系的总有机碳（ＴＯＣ）含量降低，ｐＨ值下降，过氧化氢可以促进腐殖酸的光解，其光解过程遵循一级动力学规律。计算了不同来源腐殖酸光解的速率及光解半衰期，发现土壤和泥炭腐殖酸比大骨节病病区饮水中腐     

Fate of organo‐heavy metal complexes of sludges from domestic wastes in soils: A simplified modelization

Simplified models provided information on the binding ability of organic acids with trace elements, the distribution of the formed organo‐heavy metal complexes at different pH, and the biological stability (biodegradation ability) of these complexes.     

Alpha-thalassaemia prenatal diagnosis by two PCR-based methods

In Cyprus all couples carrying α⁰-thalassaemia mutations are detected in the course of the thalassaemia carrier screening program and prenatal diagnosis is offered to all of them. Prenatal diagnosis for α-thalassaemia is routinely done by two independent molecular methods. With the first method, the mutations of the parents are directly determined by gap-PCR and then the chorionic villus sample (CVS) is examined for the presence of these mutations. With the other method, a (CA)_n repeat polymorphic site located between the ψα₁- and α₂-globin genes is used for determining the presence or absence of the normal and mutant alleles. In the period from 1995 to 1999, molecular analysis of 46 couples in which haematological data were consistent with deletion of two α-globin genes in both partners indicated that only 13 of them were actually at risk for haemoglobin (Hb) Bart's hydrops fetalis and prenatal diagnosis was provided in 16 pregnancies. The molecular diagnosis was possible in all cases with the use of both gap-PCR and (CA)_n repeat polymorphisms analysis. No misdiagnosed cases for α-thalassaemia have been reported to date. Copyright © 2001 John Wiley & Sons, Ltd.     

AN ANALYSIS OF PLAYA LAKE WATER UTILIZATION ON THE TEXAS HIGH PLAINS1

ABSTRACT: This paper examines the spatial, temporal and legal aspects of playa lake water utilization on the semi-arid Texas High Plains. These small basins of interior drainage collect and briefly hold an estimated two to three million acre-feet of runoff water annually, representing from one-fourth to one-third the quantity of groundwater pumped from the dwindling Ogallala aquifer. Once considered a detriment to farming operations, there is now increased interest in using playa water more effectively. At present direct pumping is the chief method of utilization, and modification of lake bottoms to concentrate runoff and reduce evaporation is the most widespread conservation practice. The use of playa water for groundwater reacharge is hampered by as yet unsolved technical problems. For many years the question of ownership of playa water remained unsettled. The Texas Water Rights Commission now classes it as diffused surface water, which under Texas law may be used by the landowner, though some legal problems remain. For play lakes to be effectively integrated into the regional water resource it becomes imperative that all present and prospective water utilization problems be identified and resolved.     

PROBLEMS OF PUBLIC ACCESS TO WATER IN TEXAS LAKES AND STREAMS1

ABSTRACT: Rapidly increasing demand for recreational use of Texas' public waters is resulting in growing conflict between riparian landowners and the public. This paper examines the public access question, certainly one of the most poorly defined and understood areas of Texas water and property law. Since the appropriation acts of the late 1800's, most surface waters are owned by the state, and are held in trust for the benefit of the people. While there is no express statutory authority giving the general public the right to use these waters, there is extensive, if often conflicting, case law recognizing such rights on navigable streams. It is equally well established that the public may not gain access by crossing private property. Definition of public and private rights is complicated by the fact that Texas land grants (with their attendant property rights) have emanated from Spain, Mexico, the Republic of Texas, and the state. Obstacles imposed by riparian landowners to public entry, use and passage, as well as spatial aspects of access, are also considered. Because public access rights are based on the peculiar circumstances of each case, it is difficult to establish general legal principles, and there is almost no reliable information to aid the recreation-seeking public. A clear legislative enunciation of public rights appears politically infeasible at present, the most immediately attainable goal lying in the area of better public education.     

Sinks for nitrogen inputs in terrestrial ecosystems: a meta-analysis of 15N tracer field studies

Effects of anthropogenic nitrogen (N) deposition and the ability of terrestrial ecosystems to store carbon (C) depend in part on the amount of N retained in the system and its partitioning among plant and soil pools. We conducted a meta-analysis of studies at 48 sites across four continents that used enriched 15N isotope tracers in order to synthesize information about total ecosystem N retention (i.e., total ecosystem 15N recovery in plant and soil pools) across natural systems and N partitioning among ecosystem pools. The greatest recoveries of ecosystem 15N tracer occurred in shrublands (mean, 89.5%) and wetlands (84.8%) followed by forests (74.9%) and grasslands (51.8%). In the short term (< 1 week after 15N tracer application), total ecosystem 15N recovery was negatively correlated with fine-root and soil 15N natural abundance, and organic soil C and N concentration but was positively correlated with mean annual temperature and mineral soil C:N. In the longer term (3-18 months after 15N tracer application), total ecosystem 15N retention was negatively correlated with foliar natural-abundance 15N but was positively correlated with mineral soil C and N concentration and C:N, showing that plant and soil natural-abundance 15N and soil C:N are good indicators of total ecosystem N retention. Foliar N concentration was not significantly related to ecosystem 15N tracer recovery, suggesting that plant N status is not a good predictor of total ecosystem N retention. Because the largest ecosystem sinks for 15N tracer were below ground in forests, shrublands, and grasslands, we conclude that growth enhancement and potential for increased C storage in aboveground biomass from atmospheric N deposition is likely to be modest in these ecosystems. Total ecosystem 15N recovery decreased with N fertilization, with an apparent threshold fertilization rate of 46 kg N x ha(-1) x yr(-1) above which most ecosystems showed net losses of applied 15N tracer in response to N fertilizer addition.     

CONJUNCTIVE MANAGEMENT OF WATER RESOURCES IN THE CONTEXT OF TEXAS WATER LAW1

ABSTRACT: This paper examines the critical interaction between existing Texas water law and the state's water resources. Conjunctive use and management of interrelated water resources, though seldom practiced, is generally considered desirable. However, a significant barrier to the coordinated, efficient use and management of water resources is the legal division of water in the various phases of the hydrologic cycle into different classes and recognition of well-defined water rights in the separate phases. Several examples of the problems which relate to, or result from, present Texas water law and which prevent correlated water resource management are discussed. Any substantive revision of Texas law, particularly ground water law, will apparently be difficult to achieve in the immediate future, primarily because of the large number of recognized private water rights and the political power inherent in them. Data necessary for operation of conjunctive management systems are gradually being acquired, and perhaps someday other hydrologic phases can be integrated with surface and ground water. Nevertheless, Texas courts and the legislature have sufficient information on the interrelated hydrologic cycle so that prospective water conflicts should be anticipated and avoided. Great care must be exercised in the recognition of new types of private water rights or extension of existing rights, because this institutional structure, once established, presents a formidable obstacle to desirable revisions of the law.     

An analysis of occupational stair accident patterns

This report describes an analysis of existing occupational injury data concerning stairway-related falls. Injury data based on reports obtained from the Ohio and California workers' compensation agencies were analyzed to identify common stair injury patterns. Frequency tabulations are provided for the following factors: (a) location (indoors vs. outdoors, on vs. off employer's premises, site category); (b) task (ascending vs. descending, body movement on the stair, task being attempted); and (c) events (precipitating actions and conditions). One of the most outstanding findings is that 92 % of the injuries occurred when the worker was descending the stair, i.e., 636 of the 688 cases in which direction of travel was indicated. Additionally, injury records from the New York and Ohio workers' compensation agencies were used to rank industries in terms of combined frequency and severity rates of stairway-related injuries.