36,488 research outputs found

    Psychiatric illness predicts poor outcome after surgery for hip fracture: a prospective cohort study

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    Background. Hip fracture is common in the elderly. Previous studies suggest that psychiatric illness is common and predicts poor outcome, but have methodological weaknesses. Further studies are required to address this important issue. Methods. We prospectively recruited 731 elderly participants with hip fracture in two Leeds hospitals. Psychiatric diagnosis was made within 5 days of surgery using the Geriatric Mental State schedule and other standardized instruments, and data on confounding factors was collected. Main study outcomes were length of hospital stay, and mortality over 6 months after fracture. Results. Fifty-five per cent of participants had cognitive impairment (dementia in 40% and delirium in 15%), 13% had a depressive disorder, 2% had alcohol misuse and 2% had other psychiatric diagnoses. Participants were likely to remain in hospital longer if they suffered from dementia, delirium or depression. The relative risks of mortality over 6 months after hip fracture were increased in dementia and delirium, but not in depression. Conclusions. Psychiatric illness is common after hip fracture, and has significant effects on important outcomes. This suggests a need for randomized, controlled trials of psychiatric interventions in the elderly hip fracture population

    Application and sensitivity investigation of Fourier transforms for microwave radiometric inversions

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    Existing microwave radiometer technology now provides a suitable method for remote determination of the ocean surface's absolute brightness temperature. To extract the brightness temperature of the water from the antenna temperature equation, an unstable Fredholm integral equation of the first kind was solved. Fast Fourier Transform techniques were used to invert the integral after it is placed into a cross-correlation form. Application and verification of the methods to a two-dimensional modeling of a laboratory wave tank system were included. The instability of the Fredholm equation was then demonstrated and a restoration procedure was included which smooths the resulting oscillations. With the recent availability and advances of Fast Fourier Transform techniques, the method presented becomes very attractive in the evaluation of large quantities of data. Actual radiometric measurements of sea water are inverted using the restoration method, incorporating the advantages of the Fast Fourier Transform algorithm for computations

    Elastic and plastic analysis of pressure vessel weld lands with mismatch

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    Elastic and plastic analysis of pressure vessel weld lands with mismatc

    Elastic and plastic stresses at weld sinkages and other discontinuities in pressure vessels

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    Mismatch and weld sinkage problems of pressure vessel geometric discontinuities studied in design graphs and test progra

    A unified acquisition system for acoustic data

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    A multichannel, acoustic AM carrier system was developed for a wide variety of applications, particularly for aircraft noise and sonic boom measurements. Each data acquisition channel consists of a condenser microphone, an acoustic signal converter, and a Zero Drive amplifier, along with peripheral supporting equipment. A control network insures continuous optimal tuning of the converter and permits remote calibration of the condenser microphone. With a 12.70-mm (1/2-in.) condenser microphone, the converter/Zero Drive amplifier combination has a frequency response from 0 Hz to 20 kHz (-3 db), a dynamic range exceeding 70 db, and a minimum noise floor of 50 db ref. 20 micro Pa) in the band 22.4 Hz to 22.4 kHz. The system requires no external impedance matching networks and is insensitive to cable length, at least up to 900 m (3,000 ft). System gain varies only + or - 1 db over the temperature range 4 to 54 C (40 to 130 F). Adapters are available to accommodate 23.77-mm (1-in.) and 6.35-mm (1/4-in.) microphones and to provide 30-db attenuation. A field test to obtain the acoustical time history of a helicopter flyover proved successful

    Competition and productivity: a review of evidence

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    Does competition spur productivity? And if so, how does it do so? These have long been regarded as central questions in economics. This essay reviews the literature that makes progress toward answering both questions.Competition ; Monopolies ; Productivity

    Competition at work : railroads vs. monopoly in the U.S. shipping industry

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    This study primarily establishes two things: (1) that monopoly has been pervasive in the U.S. water transportation industry in both the 19th and 20th centuries and has led to prices above competitive levels and the adoption of inefficient technologies and (2) that the competition of railroads has greatly weakened this monopolistic tendency, leading to lower water transport prices and fewer inefficient technologies. The study establishes these points using standard economic theory and extensive historical U.S. data on the behavior of unions and shipping companies. These gains from competition have been ignored by researchers studying the contribution of railroads to U.S. economic growth. Researchers have assumed that if railroads had not been developed, the long-distance transportation industry would have been competitive. This study shows that it would not have been. The quantitative estimates of previous studies thus are likely to have significantly understated the gains from the development of railroads.Transportation ; Monopolies
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