2,305 research outputs found

    R&D Spillovers and the Case for Industrial Policy in an Open Economy

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    In this paper we consider the case for subsidies towards firms which generate R&D spillovers in open economies. We show that many expected results are overturned in the presence of strategic behaviour by firms. Local R&D spillovers to other domestic firms may justify an R&D tax rather than a subsidy; R&D cooperation by local firms over-internalises the externality and also justifies an R&D tax; and international spillovers which benefit foreign firms may justify a subsidy, even though the government cares only about the profits of home firms.

    Hello BLAW: Bloomberg Law, the Newcomer in Legal Research, Meets Academic Users

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    There’s a new legal information provider in town. Bloomberg, a widely-known provider of business and financial data and news, has been working the past several years to create and disseminate its Bloomberg Law (BLAW) suite of services to law firms as well as to a number of law school libraries

    Comparing the Ancient Star Formation Histories of the Magellanic Clouds

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    We present preliminary results from a new HST archival program aimed at tightly constraining the ancient (>4 Gyr ago) star formation histories (SFHs) of the field populations of the SMC and LMC. We demonstrate the quality of the archival data by constructing HST/WFPC2-based color-magnitude diagrams (CMDs; M_{F555W} ~ +8) for 7 spatially diverse fields in the SMC and 8 fields in the LMC. The HST-based CMDs are >2 magnitudes deeper than any from ground based observations, and are particularly superior in high surface brightness regions, e.g., the LMC bar, which contain a significant fraction of star formation and are crowding limited from ground based observations. To minimize systematic uncertainties, we derive the SFH of each field using an identical maximum likelihood CMD fitting technique. We then compute an approximate mass weighted average SFH for each galaxy. We find that both galaxies lack a dominant burst of early star formation, which suggests either a suppression or an under-fueling of early star formation. From 10-12 Gyr ago, the LMC experienced a period of enhanced stellar mass growth relative to the SMC. Similar to some previous studies, we find two notable peaks in the SFH of the SMC at ~4.5 and 9 Gyr ago, which could be due to repeated close passages with the LMC, implying an interaction history that has persisted for at least 9 Gyr. We find little evidence for strong periodic behavior in the lifetime SFHs of both MCs, suggesting that repeated encounters with the Milky Way are unlikely. Beginning ~3.5 Gyr ago, both galaxies show increases in their SFHs, in agreement with previous studies, and thereafter, track each other remarkably well. (abridged)Comment: 9 pages, 5 Figures, Accepted for Publication in MNRA

    Assessment of neuromuscular and haemodynamic activity in individuals with and without chronic low back pain

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    BACKGROUND: Biering-Sørenson (1984) found that individuals with less lumbar extensor muscle endurance had an increased occurrence of first episode low back pain. As a result, back endurance tests have been recommended for inclusion in health assessment protocols. However, different studies have reported markedly different values for endurance times, leading some researchers to believe that the back is receiving support from the biceps femoris and gluteus maximus. Therefore, this study was designed to examine the haemodynamic and neuromuscular activity of the erector spinae, biceps femoris, and gluteus maximus musculature during the Biering-Sørenson Muscular Endurance Test (BSME). METHODS: Seventeen healthy individuals and 46 individuals with chronic low back pain performed the Biering-Sørenson Muscular Endurance Test while surface electromyography was used to quantify neuromuscular activity. Disposable silver-silver-chloride electrodes were placed in a bipolar arrangement over the right or left biceps femoris, gluteus maximus, and the lumbosacral paraspinal muscles at the level of L(3). Near Infrared Spectroscopy was used simultaneously to measure tissue oxygenation and blood volume changes of the erector spinae and biceps femoris. RESULTS: The healthy group displayed a significantly longer time to fatigue (Healthy: 168.5s, LBP: 111.1s; p ≤ 0.05). Significant differences were shown in the median frequency slope of the erector spinae between the two groups at 90–100% of the time to fatigue while no significant differences were noted in the haemodynamic data for the two groups. CONCLUSION: Although the BSME has been recognized as a test for back endurance, individuals with chronic LBP appear to incorporate a strategy that may help support the back musculature by utilizing the biceps femoris and gluteus maximus to a greater degree than their healthy counterparts

    Evaluation of the Impact of Transthoracic Endoscopic Sympathectomy on Patients with Palmar Hyperhydrosis

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    AbstractObjectives. We assessed the impact of transthoracic endoscopic sympathectomy (TES) on the quality of life of patients with palmar hyperhydrosis.Design. A retrospective questionnaire based study.Methods. Patients undergoing TES at our institution between 1997 and 2002 received a SF-36 quality of life postal questionnaire. The pre- and post-operative symptoms were assessed. Statistical analysis was by means of the Student's t test.Results. Ninety-four TES were carried out in 62 patients. Forty-one cases were female. The age range was 17–64 years. The mean follow-up period was 38.46 months. Mean hospital stay was 3 days. Compensatory hyperhydrosis was reported in 29 cases and only considered severe in four cases (9.7%). Forty-one patients replied to the questionnaire (66%). The overall quality of life (as assessed by the SF-36 form) was unanimously improved (p<0.0009) and demonstrated significant improvements in social functioning (p<0.0002), physical role limitations (p<0.0007), emotional well-being (p<0.0007) and overall energy levels (p<0.05).Conclusion. TES resulted in significant improvements inpatient's overall quality of life, social and emotional functioning. The procedure is associated with minimal morbidity and only a short inpatient stay is required. Patients should be cautioned on the possibility of compensatory hyperhydrosis which may occur in a small number of cases

    Uncertainty Quantification Reveals the Physical Constraints on Pumping by Peristaltic Hearts

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    Most biological functional systems are complex, and this complexity is a fundamental driver of diversity. Because input parameters interact in complex ways, a holistic understanding of functional systems is key to understanding how natural selection produces diversity. We present uncertainty quantification (UQ) as a quantitative analysis tool on computational models to study the interplay of complex systems and diversity. We investigate peristaltic pumping in a racetrack circulatory system using a computational model and analyse the impact of three input parameters (Womersley number, compression frequency, compression ratio) on flow and the energetic costs of circulation. We employed two models of peristalsis (one that allows elastic interactions between the heart tube and fluid and one that does not), to investigate the role of elastic interactions on model output. A computationally cheaper surrogate of the input parameter space was created with generalized polynomial chaos expansion to save computational resources. Sobol indices were then calculated based on the generalized polynomial chaos expansion and model output. We found that all flow metrics were highly sensitive to changes in compression ratio and insensitive to Womersley number and compression frequency, consistent across models of peristalsis. Elastic interactions changed the patterns of parameter sensitivity for energetic costs between the two models, revealing that elastic interactions are probably a key physical metric of peristalsis. The UQ analysis created two hypotheses regarding diversity: favouring high flow rates (where compression ratio is large and highly conserved) and minimizing energetic costs (which avoids combinations of high compression ratios, high frequencies and low Womersley numbers)
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