Synchronized External Pulsation for Improved Tolerance to Acceleration Stress: Model Studies and Preliminary Experiments

Synchronized external pulsation is proposed as a method to improve tolerance to acceleration stress. This technique uses a modified anti-G suit which is pressurized and depressurized synchronously with the heart cycle. The feasibility of the procedure has been studied using a computer model of the cardiovascular system which includes the effects of Gz stress, and contains simulations of baroreceptor control of heart rate and venous tone. Model predictions indicate that for unprotected subjects, carotid pressure at eye level (ophthalmic artery pressure) decreases to 20 mmHg (beginning of central light loss) at approximately +3.6 Gz. Applying standard anti-G suit pressure to the model increases this level to 5.3 Gz. When synchronized external pulsation of 2 psi is superimposed on the standard anti-G suit pressure, the tolerance to acceleration stress is further augmented by at least 0.9 G above the protection afforded by the standard anti-G suit alone. A set of preliminary experiments on human subjects to test the feasibility of using the technique in the high-G environment has also been carried out. The results under various protection modes compare favorably to the model predictions. Our results suggest that the computer model presented here is a useful tool for studying cardiovascular responses under +GZ stress. It also indicates that using synchronized external pulsation pressure superimposed on the standard anti-G suit pressure may offer extra protection to acceleration stress.     

Task Switching After Cerebellar Damage.

The authors of this study investigated task switching following cerebellar damage. The study group consisted of 7 children and adolescents (M age = 13.8 years) who underwent surgical removal of a benign posterior fossa tumor. They were tested at a sufficient interval after surgery (M lag = 6.13 years) for restoration of normal cognitive skills and intelligence. Although all showed normal learning of the task compared with control participants, when rapid behavioral changes were required (short preparation time), they exhibited behavioral rigidity manifested by enhanced switching cost. These results are in line with another study on serial reaction time with the same patients (A. Berger et al., in press). They have important implications for our understanding of the cognitive sequelae of early cerebellar damage as well as the involvement of the cerebellum in task switching. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Life cycle environmental performance and improvement of a yogurt product delivery system

A life cycle assessment was conducted to evaluate the environmental performance of the yogurt product delivery system used by Stonyfield Farm. A life cycle model was developed which included material production, manufacturing and disposition for primary and secondary packaging, as well as the related transportation links between these stages and filling, retail and the point of consumption. Product delivery systems (PDS) that utilized 4, 6, 8 and 32 oz polypropylene (PP) cups and 2 oz linear low‐density polyethylene (LLDPE) tubes were analysed. Ten strategies for improving the environmental performance of these systems were proposed and their impacts on the total life cycle burden were analysed. The life cycle energy consumption for the 2, 4, 6, 8 and 32 oz containers was 4050, 4670, 5230, 4390 and 3620 MJ/1000 lb yogurt delivered to market, respectively. Material production of the primary packaging accounted for 58% of the life cycle energy, while Distribution 3 (yogurt delivery to distributors/retailers) alone accounted for one‐third of the life cycle total energy. The life cycle solid waste profile showed that as the container size decreased, the solid waste burden increased, from 27.3 kg (32 oz) to 42.8 kg (6 oz) per 1000 lb yogurt delivered to market. This relationship was even more pronounced for the 4 oz (47.5 kg) and 2 oz (56.2 kg) product delivery systems. The greatest potential improvements in the environmental performance of the PDS are achievable through redesigning the primary packaging and using alternative manufacturing techniques for the yogurt cups. Shifting from injection moulding to thermoforming of 32 oz container reduces the life cycle energy and solid waste by 18.6% and 19.5%, respectively, primarily due to light‐weighting. Elimination of lids for 6 oz and 8 oz containers provided similar benefits. Consumers purchasing yogurt in 32 oz instead of 6 oz containers can save 14.5% of the life cycle energy and decrease solid waste by 27.2%. Copyright © 2004 John Wiley & Sons, Ltd.     

Strong mediated equilibrium

Stability against potential deviations by sets of agents is a most desired property in the design and analysis of multi-agent systems. However, unfortunately, this property is typically not satisfied. In game-theoretic terms, a strong equilibrium, which is a strategy profile immune to deviations by coalition, rarely exists. This paper suggests the use of mediators in order to enrich the set of situations where we can obtain stability against deviations by coalitions. A mediator is defined to be a reliable entity, which can ask the agents for the right to play on their behalf, and is guaranteed to behave in a pre-specified way based on messages received from the agents. However, a mediator cannot enforce behavior; that is, agents can play in the game directly, without the mediator's help. A mediator generates a new game for the players, the mediated game. We prove some general results about mediators, and mainly concentrate on the notion of strong mediated equilibrium, which is just a strong equilibrium at the mediated game. We show that desired behaviors, which are stable against deviations by coalitions, can be obtained using mediators in several classes of settings.     

Detonation Pressure of Donors as a Parameter for Assessing Detonation Transfer Probabilities

The commonly used penalty methods(such as Varicomp or varying the thickness of the out-of-line barriers), for determining the detonation transfer probability for an explosive interface, may become less practical or convenient the more insensitive explosive is the acceptor. The method proposed here suggests replacing the design donor by an explosive(substitute donor) of a lower detonation pressure. Both the acceptor and the mechanical hardware of the test system should be identical to those of the design system. It is assumed that the detonation pressures of both the design donor and the substitute donor are normally distributed. The same assumption holds also for the threshold detonation pressure required for initiating the acceptor. Following these assumptions we present a method to determine a minimum number of tests required to demonstrate a given reliability at a given confidence level. The relative standard deviation for each detonation pressure is assumed to be equal for all donors. We show then that the required number of tests to demonstrate a given reliability(at a given confidence level), practically depends on the ratio of the detonation pressures of the design donor and its test substitute. A similar method can be applied to demonstrate low probability of detonation transfer(high safety), by replacing the design donor by one of a higher detonation pressure.     

Sabbatical leave: Who gains and how much?

A rigorous quasi-experiment tested the ameliorative effects of a sabbatical leave, a special case of respite from routine work. We hypothesized that (a) respite increases resource level and well-being and (b) individual differences and respite features moderate respite effects. A sample of 129 faculty members on sabbatical and 129 matched controls completed measures of resource gain, resource loss, and well-being before, during, and after the sabbatical. Among the sabbatees, resource loss declined and resource gain and well-being rose during the sabbatical. The comparison group showed no change. Moderation analysis revealed that those who reported higher respite self-efficacy and greater control, were more detached, had a more positive sabbatical experience, and spent their sabbatical outside their home country enjoyed more enhanced well-being than others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Knowledge exchange in the shrines of knowledge: The “how’s” and “where’s” of knowledge sharing processes

Academic conferences are places of situated learning dedicated to the exchange of knowledge. Knowledge is exchanged between colleagues who are looking to enhance their future research by taking part in several formal and informal settings (lectures, discussions and social events). We studied the processes of knowledge sharing and the influence of the use of IT at the International Conference of Information Systems (ICIS2007) held in Montréal. We describe the categories of knowledge content shared at the conference. Two forms of knowledge sharing were analyzed: formal, guided, planned knowledge sharing in lectures or discussions, and informal knowledge exchange during social events. Data were collected from 274 participants at the conference. The intensity of knowledge sharing in the formal settings was higher compared to the informal settings and was perceived as contributing to future research and to the creation of social relationships. In contrast, informal knowledge sharing contributed mainly to job enhancement and to the initiation of meetings. The discussion centers on planning and evaluating conferences in terms of seeking, creating and sustaining knowledge sharing.     

Capacitance voltage characterization of poly SiSiO2Si structures

The high frequency C-V characteristics of poly SiSiO₂Si capacitors have been studied. It is shown that the poly SiSiO₂Si capacitor C-V characteristics are significantly different from the corresponding metal-SiO₂Si capacitor due to field penetration into the poly Si layer. A comparison of the theoretical and measured C-V characteristics gives an estimate of the surface state charge density at the poly SiSiO₂ interface and indicates that the surface potential behavior of this interface is trap and surface state dominated up to poly silicon impurity concentrations of approximately 10¹⁷ cm^?3.     

Trichothecium roseum的酸碱属性及pH值对其胞外酶活性和致病性的影响

目的：明确粉红单端孢（Trichothecium roseum）侵染果实的酸碱性质,测定3 种pH值孢子悬浮液接种对苹果果实病斑直径及胞外酶活性的影响。方法：用T. roseum接种“富士”苹果,测定果实病斑处的pH值变化。用pH值分别为3、5和7的孢子悬浮液接种果实,观察接种对果实病斑直径及病斑处果胶酶和纤维素酶活性的影响。结果：T. roseum接种后果实病斑处的pH值显著升高,由第0天的3.54升高至第12天的4.84,提高了36.7%。3 种pH值孢子悬浮液接种果实后,以pH 7接种的果实病斑直径最大,第9天时分别高出pH 5与pH 3接种的35.2%与68.0%。pH 7接种的果实病斑处具有最高的果胶酶及纤维素酶活性,第9天时的果胶甲酯酶、果胶甲基多聚半乳糖醛酸酶、多聚半乳糖醛酸酶活性分别为pH 3接种的2.95、1.61 倍和1.68 倍,为pH 5接种的2、1.25 倍和1.39 倍。此外,pH 7接种的果实病斑处纤维素酶和β-葡萄糖苷酶第9天的活性分别为pH 3接种的1.97 倍和1.64 倍,为pH 5接种的1.33 倍和1.3 倍。结论：T. roseum属碱化菌,中性或偏碱环境可提高该菌损伤接种苹果果实病斑处的胞外酶活性,增强其致病性。     

Kinetics of sensory quality changes in soymilk during thermal processing,by parametric and non‐parametric data analyses

Soymilk was subjected to various heat treatments at 90, 120 and 140 °C for various lengths of time. The colour and flavour of the soymilk samples were evaluated by a sensory panel consisting of eight semi‐trained assessors on (1) a 9‐unit hedonic scale, with analysis based on the assumption that the units are equidistant, and (2) a 15‐point hedonic ‘Smiley’ pictorial scale, the results being analysed non‐parametrically. The proportion (%) of ratings higher than or equal to/higher than the overall median of the samples was used as a rigorous estimate of product quality. These values were used to determine the colour and flavour changes in heated soymilk and their temperature dependence. The Z‐values derived from the parametric and non‐parametric analyses were in close agreement, ranging from 31 to 33 °C and from 30 to 32 °C for colour and flavour respectively. © 2000 Society of Chemical Industry