17 research outputs found

    Winter/summer mesopause temperature transition at Davis (69°S) in 2011/2012

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    We present quasi-continuous measurements of temperature profiles in the Southern Hemisphere mesopause region during the transition from winter to summer conditions in 2011/2012. In a period of 120 days around solstice, we have performed iron lidar observations at Davis (69°S), Antarctica, for a total of 736 h. The winter/summer transition is identified by a downward shift of the mesopause which occurs on 8 November 2011. Soon after transition, mesopause heights and temperatures are similar to the Northern Hemisphere (NH) colatitude summer (88 km, 130 K). Around solstice, the mesopause is elevated for several days by 4–5 km and is colder than typical NH temperatures by 10 K. In this period individual profiles show temperatures as low as 100 K. The occurrence of polar mesosphere summer echoes is closely connected to low temperatures. Below 88 to 90 km and in the main summer season of 2011/2012 temperatures at Davis are generally warmer compared to the NH by 5–15 K, whereas temperatures are generally colder above 90 km. The winter/summer transition and the first appearance of polar mesosphere summer echoes are strongly correlated to maximum zonal winds in the stratosphere which constrain gravity waves with eastward momentum reaching the mesosphere. At the breakdown of the stratospheric vortex around solstice, the mesopause is higher and, surprisingly, colder than normal

    Variations in dynamic knee valgus and gluteus medius onset timing in non-athletic females related to hormonal changes during the menstrual cycle.

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    It has been suggested that activities of daily living could contribute to the occurrence of ACL injury in females. Currently, no studies have focused on the lower extremity behavior of a non-athletic population to compare or understand the lower extremity adeptness towards daily movements that mimic athletic tasks. Our hypothesis was that increased knee valgus angles would occur during the late follicular phase of the menstrual cycle accompanied by different onset timing of the gluteus medius muscle. In a controlled laboratory study, 23 non-athletic collegiate females participated and 15 subjects comprised the final sample for statistical analysis. Subjects performed a single leg drop landing maneuver while 3-D knee kinematics and gluteus medius muscle onset timing were assessed throughout three distinct phases of the menstrual cycle, confirmed by blood hormone analysis. In general, knee valgus angles were significantly less in the luteal phase compared to both follicular phases (p\u3c0.005), while differences were not observed for gluteus medius onset timing (p=0.936). As a decreased knee joint valgus angle was observed during the luteal phase, it was hypothesized that the hormone progesterone could significantly influence knee kinematics during a dynamic task. However, such influence was not observed for gluteus medius EMG onset timing as a significant correlation between gluteus medius onset timing and knee valgus angle could not be determined

    Self-confidence and knowledge of German ICU physicians in palliative care – a multicentre prospective study

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    Abstract Background Little is known about ICU physicians’ self-confidence and knowledge related to palliative care. Our objective was to investigate self-confidence and knowledge of German ICU physicians related to palliative care, and to assess the impact of work experience, gender, specialty and additional certifications in pain or palliative medicine. Methods In a multicentre prospective observational study ICU physicians of ten hospitals were asked to rate their self-confidence and to complete a multiple choice questionnaire for the assessment of knowledge. Beyond descriptive statistics and non-parametric tests for group comparisons, linear regression analysis was used to assess the impact of independent variable on self-confidence and knowledge. Spearman‘s rank test was calculated. Results 55% of answers in the knowledge test were correct and more than half of the participants rated themselves as “rather confident” or “confident”. Linear regression analysis revealed that an additional certificate in either pain or palliative medicine significantly increased both knowledge and self-confidence, but only 15 out of 137 participants had at least one of those certificates. Relation between self-confidence and the results of the knowledge test was weak (r = 0.270 in female) and very weak (r = −0.007 in male). Conclusions Although the questionnaire needs improvement according to the item analysis, it appears that, with respect to palliative care, ICU Physicians’ self-confidence is not related to their knowledge. An additional certificate in either pain or palliative medicine was positively correlated to both self-confidence and knowledge. However, only a minority of the participants were qualified through such a certificate

    Foreign direct investment and firm innovation in selected sub-Saharan African Countries

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    The impact of innovation on every economy cannot be overemphasized. Hence, this study investigates empirically the impact of inward FDI on host firms' innovation in Nigeria and South Africa using the World Bank Enterprise Survey dataset (WBES). In examining this relationship between FDI and firm innovation, two robust instrumental variable estimation techniques (two-stage least squares and limited information maximum likelihood) were employed so as to account for any endogeneity problems. The study establishes that while FDI positively influences firm innovation in Nigeria, it does not have any impact on firm innovation in South Africa. This study thus presents evidence that context is very crucial in the investigation of the link between FDI and innovation in Sub-Saharan Africa. It is thus recommended that FDI attraction into Africa should be selectively done with more focus on inflows from more advanced and innovative economies
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