Not available / text

To understand how falls occur during walking in older adults, we need to understand how the nervous system maintains stability, and how aging affects walking. Four studies were conducted to better understand the effect of age on gait. Older adults display higher gait variability compared to young adults, possibly because of their slower walking. We compared gait stability at multiple controlled walking speeds. Greater gait variability in healthy elderly existed independent of slower walking. Their diminished strength and flexibility partly explained this difference. To explain slower walking in the elderly, some have suggested that muscle weakness and stiffness may force people to walk slower. Others have suggested that people choose to walk slower to be more stable. We compared dynamic stability of gait at multiple speeds. Healthy older adults also exhibited more stability at slower speeds, yet walked at speeds comparable to young adults despite the lower strength and flexibility. Therefore, weakness and stiffness may not force healthy older adults to walk slower. The goal of the nervous system during walking may be to maintain stability of superior segments. We tested whether superior segments are more stable than inferior segments during walking. Superior segments exhibited less orbital stability during preferred walking speed, in contrast to previous suggestions. This highlighted the importance of trunk control during gait. The effects of aging on the fluctuations in the muscle activity during gait are not well understood. We quantified the stride-to-stride fluctuations of EMG as a measure of muscle activation patterns in state-space. Variability increased with speed except in the gastrocnemius. Orbital stability was less in older adults, suggesting that deviations in the EMG amplitude pattern were not readily corrected. Less local stability was seen in older adults, suggesting that older adults were more sensitive to perturbations. Together, these findings suggest that trunk control is important during gait. Strength and flexibility deficits help explain higher variability and lower stability in older adults. Future work will need to address the effect of strength interventions, neurophysiological decline on gait stability and fall risk.

Knowledge of the consequences of a nuclear criticality accident in aqueous fissile solutions is necessary to design the processing equipment for such solutions. The data at the disposal of designers before 1967 was provided by actual critically accidents. In 1968, the Service d'Etudes de Criticite of the French Commissariat a L'Energie Atomique initiated a program of systematic experimental aqueous solution nuclear excursions which were initiated intentionally to obtain solution criticality accident data. This program was designated "Consequence Radiologiques d'un Accident de Criticite" (CRAC). Although not intended to study the evolution of a solution nuclear criticality accident, the Kinetic Experiment on Water Boiler (KEWB) demonstrated the dependence of the nuclear excursion on parameters such as solution temperature and radiolytic gas. Similarly, the CRAC program results indicated the excursion was governed by parameters such as the solution addition rate, initial neutron population, solute concentration, and thermal and radiolytic gas feedback. The energy deposited in a fissile solution is the sum of the energies contributed by the radiation sources. The majority of the energy is deposited by the fission fragments. One feature of the energy deposition is a commensurate increase in the system temperatures which affects the solution volume and thereby the neutron leakage probability. A second feature is the decomposition of the water molecule which results in release of H(,2) and O(,2) in the solution. Microbubbles are nucleated in the fissile solution by a localized thermal spike generated by a fission fragment. Initially, the microbubble contains a mixture of radiolytic gas and water vapor. Below the boiling point the vapor condenses quickly, leaving a gas microbubble. Unless the solution is supersaturated, the gas bubble will dissolve in a few microseconds. However, in a supersaturated solution the bubble will grow and produce negative feedback by increasing neutron leakage. The analysis for this study employs two mathematical models for the radiolytic gas feedback. One assumes the radiolytic gas concentration is a linear function of the energy release and the nucleation rate is a linear function of the power (Energy model). The other assumes a correlation between the system pressure and the radiolytic gas feedback (Pressure model). Both models have been incorporated into a space-independent kinetic computer code, MACKIN, while the pressure model was also incorporated into a space-dependent code, AZPAD, (Space-dependent model). The model incorporation provides a numerical tool with which to analyze a nuclear excursion in an aqueous fissile solution. The models have been successful in predicting the peak power, burst energy, and maximum system pressure for the first burst in both KEWB and CRAC experiments.

No description available.

Vi har i detta arbete valt att titta närmare på problemet med att vissa bulklaster, exempelvis träpellets och flis, kan orsaka en skadlig atmosfär i lastrummen samt i kringliggande utrymmen. Vårt syfte var att finna lösningar på problemet med att människor råkat illa ut i olyckor involverande nämnda laster samt att bygga upp en erfarenhetsbank som folk i branschen kan ta del av och även dra lärdomar utifrån. Efter att ha läst in oss på ämnet via bl.a. tidningsurklipp, började undersökningen med att vi studerade olycks- samt forskningsrapporter. Vidare valdes deltagarna ut från ett flertal sjöfartsorienterade företag och organisationer. Dessa kontaktades samt intervjuades. Undersökningen visade att det tycks finnas ett flertal orsaker till att olyckor med dessa laster sker. Bl.a. nämndes okunskap och bristande rutiner. Några förslag på lösningar som gavs var att alltid hålla farliga utrymmen låsta samt att aldrig någonsin nöja sig med att mäta syrehalten. Koloxiden är minst lika farlig. / In this work we have chosen to investigate the problem with some solid bulk cargoes, for example woodchips and pellets, generating a dangerous atmosphere in cargo holds and surrounding areas. Our purpose was to find solutions to the problem with people suffering in accidents concerning the already mentioned cargoes and to create a document containing experiences from the people in the business. Later on, others would have an opportunity to learn from these experiences. To start with, we read articles about this problem and soon thereafter begun the investigation. Reports from accidents and scientistic work were read and later on we contacted our participants and proceeded with the interviews. These participants were chosen from several different companies in the shipping cluster. Our work shoved us several different reasons why the accidents occur. Lack of experience and bad routines were mentioned. The suggested actions to be taken were among other things, to lock the doors and not forget to measure the carbon monoxide levels.

No description available.

The year 2003 marks the entering into force of the new Montreal Convention governing certain rules for international carriage by air. This, however, does not mean that the international community, including States, air carriers and their agents, passengers, shippers and consignors, insurance companies and the legal community in general (specially aviation lawyers and judges) shall only rely on this instrument. The Warsaw Convention and its complementary instruments, known as the Warsaw System, is still applicable and in certain circumstances, may be the only existing relation binding States and air carriers, especially in terms of liability and compensatory damages arising from an accident or delay. Good knowledge of the conflicts that may arise within the existing international legal framework is an asset for a successful civil aviation case consultancy or trial.

Article 17 in the Warsaw Convention 1929, the core provision to all liability for passenger injury and death, has been the most litigated Article of the Warsaw Convention. The main reason for this is that the Warsaw Convention, the axis of private international air law, unfortunately did not provide clear definitions regarding "accident" and "bodily injury" in the Article 17. Its amendments, the Hague Protocol 1955 and the Guatemala Protocol 1971, did not succeed in clarifying the meanings. Although the Montreal Conference 1999 witnessed strong debates regarding the amendment of Article 17, the Montreal Convention 1999 did not succeed in changing Article 17. Since the Warsaw System did not provide definitions of "accident" and "bodily injury", each State has interpreted the two terms individually. Inconsistency in interpreting "accident" and "bodily injury" has emerged, since every State has a different jurisprudence. This phenomenon has created confusion in the international air transport community. In order to clear up the confusion, the International Civil Aviation Organization should amend Article 17 to specify and clarify the terms: "accident" and "bodily injury", while balancing the interests of all parties in the international air transport community.

The sample included 29 healthy competitive male distance runners. Bilateral measurements were taken for selected variables of the talocalcaneal flexibility by means of a mechanical goniometer, and of the peak isokinetic knee strength on a Cybex II device. The frontal and horizontal plane motions of the lower limbs of the subjects were recorded by high speed filming and videotaping while they were running on a motor driven treadmill at their training pace under two conditions: with running shoes and barefoot. A detailed description of each runner's history was obtained and bilateral dominance characteristics were determined. Significant functional asymmetries were found for subtalar joint flexibility (eversion, inversion, and eversion/inversion ratio) and peak isokinetic knee strength (flexion, extension, total, and flexion/extension ratio). Significant kinematic asymmetries were revealed during the foot support phase in lower leg angle, rearfoot angle, mediolateral velocity of the foot, and in some temporal parameters. The two running conditions differed significantly only for the pretouchdown phase of support. Significant trends of association were identified between selected components of the lower limb functional and kinematical asymmetries which were characterized by consistent laterality patterns. Multivariate asymmetry components and running injury patterns were independent. Only asymmetries in foot pronation during barefoot running tended to significantly differentiate between runners grouped by injury incidence. The phenomenon of functional and kinematic asymmetries in runners is warranted.

The high rate of accidents recorded in South African industry and the human and economic consequences involved reflect inadequacies in existing safety management policies and practices. The universally accepted right of employees to protection and the demands of social policy make the prevailing situation unacceptable. The complexities of the parameters of the employer's obligation for sound safety management requires practical guidelines for its understanding and application. The aim of this research is therefore to determine these parameters and to provide guidelines for their application. The parameters at issue are regulated by the principles of modern labour law, the developing common law, and statutory law such as MOSA. In order to pursue sound management practices and employment relations, the employer must not only take cognizance of his legal obligations but also various humanitarian, social and economic considerations. To correlate the complex nature of safety management with the demands of social policy, it is necessary to apply an appropriate standard of conduct to which every safety practice must adhere. This standard relates to the employer's general duty to take fair and reasonable precautions to eliminate or minimize occupational hazards. The employer's conduct is measured in terms of the objective standard of the reasonable employer in labour relations. The concept of reasonableness is therefore fundamental to the formulation of the parameters of the employer's obligation. The parameters are shown to centre round the reasonable foresight of the likelihood of harm and the implementation of reasonable precautionary measures to guard against the occurrence of such foreseeable harm. Furthermore, an unforeseeable incident that occurs in spite of preventive measures taken may reflect the need for subsequent preventive and corrective action. There is clearly scope for employers to adopt a more proactive approach in promoting sound safety management practices. Certain statutory, attitudinal and policy changes will be necessary for improved working conditions. These changes will include the formulation and implementation of an objectively-based safety policy that will facilitate the application of the parameters established. The proposed model flow-chart makes it possible to establish whether the parameters have been effectively implemented, and whether the employer or a third party is liable for a particular accident. / Thesis (Ph.D.)-University of Natal, Durban, 1993.