Vertical swimming in wave-induced currents as a control mechanism of intertidal migration by a sand-beach isopod

Both the vertical and horizontal distributions ofEurydice pulchra (Leach) within the water column of the surf zone were recorded throughout complete tidal cycles on a sandy beach in North Wales during the summer of 1989. Upon emerging from the sand, the isopods tended to swim up in the water column, where transport onshore would be facilitated by the wave-induced, onshore currents which laboratory wave-tank experiments have confirmed to occur near the water surface. This combination of active and passive transport to the water's edge results in high numbers of individuals in the narrow swash zone. At and just after the time of high tide, individuals swim to the water/sediment interface where, as again confirmed by wave-tank experiments, the predominant water movement is offshore. Continued swimming near the bottom during the ebb tide before reburrowing in the sand ensures transport downshore and avoidance of stranding above the characteristic level of zonation on the shore. Vertical migrations ofE. pulchra in the water column permit differential exploitation of up and downshore currents to achieve horizontal migration.     

康滇地轴东缘铅锌矿床铅硫同位素地球化学研究

康滇地轴东缘不同时代碳酸盐地层中铅锌矿床的铅同位素研究表明 ,其2 0 7Pb/2 0 4 Pb与2 0 6 Pb/ 2 0 4 Pb呈良好线性关系 ,2 0 7Pb/ 2 0 6 Pb和2 0 8Pb/ 2 0 6 Pb为一常数。结合对本区矿床的稀土元素及成矿流体地球化学的研究 ,判定不同层位铅锌矿床是在同一个成矿体系同时形成的 ,一次成矿 ,其成矿年龄为 2 4 5Ma(峨眉运动 ) ;同时说明不同矿床成矿金属有相同的来源 ,主要来自上地幔。成矿硫以来自地层中的硫酸盐还原硫为主 ,幔源硫次之。本区铅锌矿床的成矿作用与峨眉山玄武岩的喷流关系密切 ,这是与著名的MVT型铅锌矿床的显著区别。     

Risk tolerance and pilot involvement in hazardous events and flight into adverse weather

INTRODUCTION: According to Lopes [Lopes, L.L. (1987). Between hope and fear: The psychology of risk. Advances in Experimental Social Psychology, 20, 255-295] tolerance of risk may be governed by sensitivity to either the opportunities for gain or threats of loss involved. Methods: In the initial study, qualified pilots were presented with 36 written flight scenarios that varied in the levels of opportunity and threat present. The pilots rated the likelihood that they would undertake each flight. Pilots were largely risk averse, as their ratings were all significantly influenced by threat. Results: The pilots whose ratings were significantly influenced by opportunity had been involved in more hazardous aviation incidents than the other pilots. In the final study, 32 qualified pilots completed both the risk tolerance measure and a simulated flight into adverse weather. The pilots who continued flying into adverse weather were less risk averse compared to the pilots who diverted. This further highlighted the link between risk tolerance and risk-taking, and suggested that some pilots may fly into adverse weather because of a greater tolerance of risk. Impact on Industry:The studies provide evidence that a measure of risk tolerance can predict potential accident involvement amongst general aviation pilots.     

An illicit economy: scavenging and recycling of medical waste

This paper discusses a significant illicit economy, including black and grey aspects, associated with medical waste scavenging and recycling in a megacity, considering hazards to the specific group involved in scavenging as well as hazards to the general population of city dwellers. Data were collected in Dhaka, Bangladesh, using a variety of techniques based on formal representative sampling for fixed populations (such as recycling operatives) and adaptive sampling for roaming populations (such as scavengers). Extremely hazardous items (including date expired medicines, used syringes, knives, blades and saline bags) were scavenged, repackaged and resold to the community. Some HCE employees were also observed to sell hazardous items directly to scavengers, and both employees and scavengers were observed to supply contaminated items to an informal plastics recycling industry. This trade was made possible by the absence of segregation, secure storage and proper disposal of medical waste. Corruption, a lack of accountability and individual responsibility were also found to be contributors. In most cases the individuals involved with these activities did not understand the risks. Although motivation was often for personal gain or in support of substance abuse, participants sometimes felt that they were providing a useful service to the community.     

Case-control study of risk factors for fatal and non-fatal injury in crashes of rotary-wing aircraft

INTRODUCTION: There have been few studies of the risk factors for fatal injury in air crashes of rotary-wing aircraft, and none of risk factors for all serious injury (fatal and non-fatal) in these aircraft. The aim of the study was to identify the potentially modifiable risk factors for injury in civil rotary-wing aircraft crashes in New Zealand. METHOD: We analyzed records from all reported civil rotary-wing aircraft crashes in New Zealand between 1988 and 1994. Air crash data from the official databases were merged with nationwide injury records and information obtained from Coroner's files. Crashes where the pilot-in-command was fatally injured were compared with crashes where the pilot-in-command was not fatally injured on 50 variables, covering pilot, aircraft, environmental, and operational characteristics. A second analysis compared crashes where the pilot-in-command was seriously injured (either fatally or non-fatally) with crashes where the pilot-in-command was not hospitalized with an injury. A series of multivariate logistic regression analyses were conducted to estimate the odds associated with each of the factors identified by the univariate analyses. RESULTS: The most significant risk factors for all serious injury were: (a) not obtaining a weather briefing, (b) off-airport location of the crash site, (c) flights carried out for air transport purposes, and (d) non-solo flights. Other risk factors, significant for fatal injury only, included post-crash fire and the nature of the crash terrain. Factors within the control of the pilot, environmental, and flight characteristics are the key determinants of the injury outcome of civil rotary-wing aircraft crashes.