5,342 research outputs found

    Physiological responses of women to simulated weightlessness: A review of the first female bed-rest study

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    Subjects were exposed to centrifugation, to lower body negative pressure (LBNP), and to exericse stress both before and after bed rest. Areas studied were centrifugation tolerance, fluid electrolyte changes and hematology, tolerance to LBNP, physical working capacity, biochemistries, blood fibrinolytic activity, female metabolic and hormonal responses, circadian alterations, and gynecology. Results were compared with the responses observed in similarly bed-rested male subjects. The bed-rested females showed deconditioning responses similar to those of the males, although with some differences. Results indicate that women are capable of coping with exposure to weightlessness and, moreover, that they may be more sensitive subjects for evaluating countermeasures to weightlessness and developing criteria for assessing applicants for shuttle voyages

    Heart catheter cable and connector

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    Ultraminiature catheter cables that are stiff enough for intravenous insertion yet flexible at the tip, sterilizable, and economical are fabricated entirely from commercially available parts. Assembly includes air passageway for reference pressures and coaxial cable for transmission of signals from the tip of catheter

    Kondo screening suppression by spin-orbit interaction in quantum dots

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    We study the transport properties of a quantum dot embedded in an Aharonov-Bohm ring in the presence of spin-orbit interactions. Using a numerical renormalization group analysis of the system in the Kondo regime, we find that the competition of Aharonov-Bohm and spin-orbit dynamical phases induces a strong suppression of the Kondo state singlet, somewhat akin to an effective intrinsic magnetic field in the system. This effective field breaks the spin degeneracy of the localized state and produces a finite magnetic moment in the dot. By introducing an {\em in-plane} Zeeman field we show that the Kondo resonance can be fully restored, reestablishing the spin singlet and a desired spin filtering behavior in the Kondo regime, which may result in full spin polarization of the current through the ring.Comment: 4 pages, 4 figure

    Evaluation of the cardiovascular system during various circulatory stresses Progress report, 1 Sep. 1968 - 1 May 1969

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    Cardiac response to chemotherapy after myocardial infraction and diagnostic methods of heart disease in man and animal

    The effect of different forms of heparin on point-of-care blood gas analysis

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    Background. Point-of-care blood gas analysis plays an integral role in the management of critically ill and injured patients presenting to the emergency department (ED). While the use of specially manufactured syringes containing electrolyte-balanced dried heparin is recommended when processing these specimens, alternatives including manually self-prepared syringes washed with liquid heparin or heparin vacutainers are still often used.Objectives. To assess the effect of two concentrations of liquid heparin and the use of heparin vacutainers on the reliability of blood gas analysis results compared with the recommended standard of dried heparin syringes in the ED setting.Methods. Blood samples were drawn from 54 patients attending a tertiary-level hospital ED. Individual samples were distributed equally among each of four different collection devices: a dried heparin syringe, self-prepared syringes washed separately with 1 000 IU/mL and 5 000 IU/mL liquid heparin, and a heparin vacutainer. Results obtained from the standard dried heparin syringes were compared with those from the other three methods.Results. For both the liquid heparin cohorts, partial pressure of carbon dioxide (pCO2), potassium (K+), sodium (Na+), ionised calcium (iCa2+) and haemoglobin had >20% of results falling beyond the total allowable error. iCa2+ and K+ results were most affected in the 5 000 IU/mL cohort and iCa2+ and Na+ in the 1 000 IU/ml cohort. pCO2, pH and iCa2+ were the most significantly affected in the heparin vacutainer cohort.Conclusions. Use of liquid heparin can result in significant negative bias in the majority of blood gas analytes, especially electrolytes. Heparin vacutainer use can result in unacceptable variations in the respiratory analytes. While standard dried heparin syringes may not always be available, it is of vital importance that practitioners be aware of these biases and limitations when using substitutes

    Extending Work Life

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    This book examines the employer perspective on how to respond to the needs and desires of older workers to delay or prolong the transition from full-time employment to complete retirement

    Extending Work Life: Can Employers Adapt When Employees Want to Delay Retirement?

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    Aging men and women are increasingly remaining in the labor force. Most often the reason for this is that they need to work additional years in order to be able to support an increasing number of years in retirement. This leaves employers scrambling for ways to adapt to a growing number of retirement-aged workers. Clark and Morrill provide a thorough assessment of the costs and benefits of accommodating later retirement ages, and they describe options employers may use to create some new form of employment contract with aging workers. The most prominent issues employers with aging workers face are declining productivity, rising labor and benefits costs, and a suboptimal age distribution of their workforces. According to the authors, employers could respond to these issues by finding new ways to accommodate older workers with, for instance, phased retirement and return-to-work policies. But the success of such policies also depends on tax policies and whether government-provided retirement benefits could be redesigned to play a role in a newly-defined employment relationship.https://research.upjohn.org/up_press/1261/thumbnail.jp

    Zero-field Kondo splitting and quantum-critical transition in double quantum dots

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    Double quantum dots offer unique possibilities for the study of many-body correlations. A system containing one Kondo dot and one effectively noninteracting dot maps onto a single-impurity Anderson model with a structured (nonconstant) density of states. Numerical renormalization-group calculations show that while band filtering through the resonant dot splits the Kondo resonance, the singlet ground state is robust. The system can also be continuously tuned to create a pseudogapped density of states and access a quantum critical point separating Kondo and non-Kondo phases.Comment: 4 pages, 4 figures; Accepted for publication in Physical Review Letter
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