Fluid thrust control system

A pure fluid thrust control system is described for a pump-fed, regeneratively cooled liquid propellant rocket engine. A proportional fluid amplifier and a bistable fluid amplifier control overshoot in the starting of the engine and take it to a predetermined thrust. An ejector type pump is provided in the line between the liquid hydrogen rocket nozzle heat exchanger and the turbine driving the fuel pump to aid in bringing the fluid at this point back into the regular system when it is not bypassed. The thrust control system is intended to function in environments too severe for mechanical controls

Policing organized crime : a new direction

Recent criminological research in the Netherlands underscores the fact that organized crime is embedded in society and the overall picture makes it clear that police emphasis on a crime fighting model of the police, based solely on criminal law will not be entirely effective. Therefore, the Twente police force developed a new strategy of policing organized crime in their region. This strategy is based on criminological knowledge and on the approach of community policing: preventive, pro-active and integrated actions taken by various partners of the police in order to reduce illegal activities of organized crime groups. This strategy, however, can only succeed when two conditions are satisfied. First, this approach can only function in an open democratic society in which numerous public and private organizations and the public feel responsible for the emergence of organized crime in their environment. Secondly, the police force and their partners must be (relatively) free of corruption. This implies that this strategy can only be effective in societies in which organized crime has not deeply penetrated democratic institutions and business organizations

The use of performance information case studies in local social services departments

New Public Management (NPM) is the commonly used label for the growing popularity of businesslike control tools in governmental organisations. NPM includes several dimensions of change, such as divisionalisation, visible and active control and a prominent role for performance measurement. Developments in Dutch local government demonstrate several of these elements of NPM. Pollitt and Bouckaert (2000) and Pollitt (2002) defined four levels of NPM change: (1) discourse; (2) decisions; (3) practices and (4) results. This paper focuses on performance measurement. The politicians and managers at the top of the investigated municipalities took the decision to adopt instruments that generate performance information. This paper seeks to explain the extent to which the information resulting from these instruments is actually being used in the management practices at work floor level. It investigates two categories of explanations for information use: characteristics of the available information (such as its contents, amount and quality) and characteristics of the organization and its routines. The paper thus analyses how decisions taken by politicians and top managers to adopt NPM relate practices at work floor level.

Nocturnal activity by the primarily diurnal Central American agouti (Dasyprocta punctata) in relation to environmental conditions, resource abundance and predation risk

An animal's fitness is in part based on its ability to manage the inherent risks (foraging costs, predation, exposure to disease) with the benefits (resource gain, access to mates, social interactions) of activity (Abrams 1991, Altizer et al. 2003, Lima & Bednekoff 1999, Rubenstein & Hohmann 1989, Wikelski et al. 2001). Thus, understanding an animal's pattern of activity is key to understanding behavioural and ecological processes. However, while numerous laboratory methodologies are available to continuously quantify activity over long periods of time, logistical difficulties have greatly hindered activity studies of animals in the field (DeCoursey 1990)

Outflow boundary conditions for 3D simulations of non-periodic blood flow and pressure fields in deformable arteries

The simulation of blood flow and pressure in arteries requires outflow boundary conditions that incorporate models of downstream domains. We previously described a coupled multidomain method to couple analytical models of the downstream domains with 3D numerical models of the upstream vasculature. This prior work either included pure resistance boundary conditions or impedance boundary conditions based on assumed periodicity of the solution. However, flow and pressure in arteries are not necessarily periodic in time due to heart rate variability, respiration, complex transitional flow or acute physiological changes. We present herein an approach for prescribing lumped parameter outflow boundary conditions that accommodate transient phenomena. We have applied this method to compute haemodynamic quantities in different physiologically relevant cardiovascular models, including patient-specific examples, to study non-periodic flow phenomena often observed in normal subjects and in patients with acquired or congenital cardiovascular disease. The relevance of using boundary conditions that accommodate transient phenomena compared with boundary conditions that assume periodicity of the solution is discussed

A method to detect baseline emission and plant damage induced volatile emission in a greenhouse

The objective of this research was to ascertain if 1) baseline emission and 2) damage induced emission of volatile plant substances could be detected under greenhouse conditions. A laboratory method was validated for analysing the air in a semi-closed greenhouse with 44 m2 floor area. This greenhouse, with a volume of 270 m3, was climate controlled and light was supplied with assimilation lamps. Sixty tomato plants (Lycopersicon esculentum Mill cv. Moneymaker) were grown in this greenhouse. These plants were artificially damaged on a weekly interval by stroking the stems. Continuous flow pumps were used to purge the air surrounding the plants through tubes containing an adsorbent. This sampling step was performed before and directly after damage of the plants. After sampling, the tubes were transferred to the lab for analysis. The analysis of volatile compounds was performed using a high-throughput gas chromatography-mass spectrometry system. The method enabled the detection of baseline level emission and the emission of volatiles released after artificially damaging the tomato plants during a 6 weeks growing period. Most dominant compounds for baseline emission were the monoterpenes ß-phellandrene, 2-carene, limonene, ¿-phellandrene and ¿-pinene. Directly after damage, these compounds showed an increase of up to 100 times compared to baseline level emission. With these results, we prove that it is possible to detect baseline- and plant damage induced volatile emission in a greenhouse. This area of research is promising but more research needs to be done to determine whether it is possible to detect plant damage due to pests and pathogens using volatile sensing

Cost-effectiveness of Spa treatment for fibromyalgia: general health improvement is not for free

Objectives: To estimate the cost-effectiveness of an adjuvant treatment course of spa treatment compared with usual care only in patients with fibromyalgia syndrome (FM). - \ud Methods: 134 patients with FM, selected from a rheumatology outpatient department and from members of the Dutch FM patient association were randomly assigned to a 2½ week spa treatment course in Tunisia or to usual care only. Results are expressed as quality-adjusted life years (QALYs) for a 6-month as well as a 12-month time horizon. Utilities were derived form the Short Form 6D (SF-6D) scores and the visual analogue scale (VAS) rating general health. Costs were reported from societal perspective. Mean incremental cost per patient and the incremental cost utility ratio (ICER) were calculated; 95% confidence intervals (CIs) were estimated using double-sided bootstrapping. -\ud Results: The data of 128 (55 spa and 73 controls) of the 134 patients (96%) could be used for analysis. Improvement in general health was found in the spa group until 6 months of follow-up by both the SF-6D (AUC 0.32 vs 0.30, P<0.05) and the VAS (AUC 0.23 vs 0.19, P<0.01). After 1yr no significant between-group differences were found. Mean incremental cost of spa treatment was E1311 per patient (95% CI 369–2439), equalling the cost of the intervention (thalassotherapy including airfare and lodging), or E885 per patient based on a more realistic cost estimate. -\ud Conclusions: The temporary improvement in quality of life due to an adjuvant treatment course of spa therapy for patients with FM is associated with limited incremental costs per patient