37,290 research outputs found
Molecular ratchets - verification of the principle of detailed balance
We argue that the recent experiments of Kelly et. al.(Angew. Chem. Int. Ed.
Engl. 36, 1866 (1997)) on molecular ratchets, in addition to being in agreement
with the second law of thermodynamics, is a test of the principle of detailed
balance for the ratchet. We suggest new experiments, using an asymmetric
ratchet, to further test the principle. We also point out methods involving a
time variation of the temperature to to give it a directional motion
Comments on a Major Range Extension of the Little-Known Acrocera bakeri (Diptera: Acroceridae)
The spider fly Acrocera bakeri Coquillett, 1904 (Diptera: Acroceridae) is reported as a new state record for Wisconsin. This is a major range extension, because this rarely-encountered species was previously known only from the western U.S., specifically Arizona, California, and Nevada. The taxonomic history of the species is briefly discussed and hypotheses are offered for its unexpected presence in Wisconsin
Involving users in service planning: a focus group approach
This paper outlines the way in which a focus group approach was used to involve service users in the possible reconfiguration of follow-up services for breast cancer patients at a North London hospital. The focus group was used to identify the priority issues for users and the development of an objective questionnaire, to survey all current service users. Within the National Health Service (NHS) the concept of user involvement has been embodied in contemporary health policy, and has become an important constituent of current policy direction. This study was the first stage of a larger stakeholder project that aimed to involve service users and clinicians in developing a new model of breast cancer follow-up service. From the focus group emerged five key themes around breast cancer follow up. They were:
• The need for reassurance after the diagnosis of cancer.
• Continuity of care.
• Privacy and dignity and other elements of the examination technique.
• Information and the detection of new symptoms.
• The opportunity to discuss feelings and worries.
In this paper, the nature of breast cancer follow-up services is outlined, and the difficulties associated with such services are discussed. The background to user involvement within the United Kingdom is explored, and the strategies that have previously been used are considered. The practical issues involved in using the focus group approach are examined, and the experience of using such an approach is outlined in this study. The involvement of service users as a key stakeholder in the process of planning change, through a participatory research strategy, ensured that their voices were heard alongside those of both hospital and primary care staff
A retrospective study of the short-term complication rate following 750 elective elbow arthroscopies
GOES I/M image navigation and registration
Image Navigation and Registration (INR) is the system that will be used on future Geostationary Operational Environmental Satellite (GOES) missions to locate and register radiometric imagery data. It consists of a semiclosed loop system with a ground-based segment that generates coefficients to perform image motion compensation (IMC). The IMC coefficients are uplinked to the satellite-based segment, where they are used to adjust the displacement of the imagery data due to movement of the imaging instrument line-of-sight. The flight dynamics aspects of the INR system is discussed in terms of the attitude and orbit determination, attitude pointing, and attitude and orbit control needed to perform INR. The modeling used in the determination of orbit and attitude is discussed, along with the method of on-orbit control used in the INR system, and various factors that affect stability. Also discussed are potential error sources inherent in the INR system and the operational methods of compensating for these errors
LED instrument approach instruction display
A display employing light emitting diodes (LED's) was developed to demonstrate the feasibility of such displays for presenting landing and navigation information to reduce the workload of general aviation pilots during IFR flight. The display consists of a paper tape reader, digital memory, control electronics, digital latches, and LED alphanumeric displays. A presentable digital countdown clock-timer is included as part of the system to provide a convenient means of monitoring time intervals for precise flight navigation. The system is a limited capability prototype assembled to test pilot reaction to such a device under simulated IFR operation. Pilot opinion indicates that the display is helpful in reducing the IFR pilots workload when used with a runway approach plate. However, the development of a compact, low power second generation display was recommended which could present several instructions simultaneously and provide information update capability. A microprocessor-based display could fulfill these requirements
Happiness as stable extraversion : internal consistency reliability and construct validity of the Oxford Happiness Questionnaire among undergraduate students
The Oxford Happiness Questionnaire (OHQ) was developed by Hills and Argyle (2002) to provide a more accessible equivalent measure of the Oxford Happiness Inventory (OHI). The aim of the present study was to examine the internal consistency reliability, and construct validity of this new instrument alongside the Eysenckian dimensional model of personality. The Oxford Happiness Questionnaire was completed by a sample of 131 undergraduate students together with the abbreviated form of the Revised Eysenck Personality Questionnaire. The data demonstrated good internal consistency reliability (alpha = .92) and good construct validity in terms of positive association with extraversion (r = .38 p < .001) and negative association with neuroticism (r = −.57 p < .001). The kind of happiness measured by the OHQ is clearly associated with stable extraversion
Flight investigation of a vertical-velocity command system for VTOL aircraft
A flight investigation was undertaken to assess the potential benefits afforded by a vertical-velocity command system (VVCS) for VTOL (vertical take-off and landing) aircraft. This augmentation system was conceived primarily as a means of lowering pilot workload during decelerating approaches to a hover and/or landing under category III instrument meteorological conditions. The scope of the investigation included a determination of acceptable system parameters, a visual flight evaluation, and an instrument flight evaluation which employed a 10 deg, decelerating, simulated instrument approach task. The results indicated that the VVCS, which decouples the pitch and vertical degrees of freedom, provides more accurate glide-path tracking and a lower pilot workload than does the unaugmented system
Analytical models and system topologies for remote multispectral data acquisition and classification
Simple analytical models are presented of the radiometric and statistical processes that are involved in multispectral data acquisition and classification. Also presented are basic system topologies which combine remote sensing with data classification. These models and topologies offer a preliminary but systematic step towards the use of computer simulations to analyze remote multispectral data acquisition and classification systems
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