1,720,979 research outputs found
Response of finger circulation to energy equivalent combinations of magnitude and duration of vibration
No full textOBJECTIVES - To investigate the acute response of finger circulation to vibration with different combinations of magnitude and duration but with the same "energy equivalent" acceleration magnitude according to current standards for hand transmitted vibration.METHODS - Finger skin temperature (FST) and finger blood flow (FBF) were measured in the middle fingers of both hands of 10 healthy men who had not used hand held vibrating tools regularly. With a static load of 10 N, the right hand was exposed to 125 Hz vibration with the following unweighted root mean square (rms) acceleration magnitudes and durations of exposure: 44 m/s2 for 30 minutes; 62 m/s2 for 15 minutes; 88 m/s2 for 7.5 minutes; 125 m/s2 for 3.75 minutes; and 176 m/s2 for 1.88 minutes. These vibration exposures produce the same 8 hour energy equivalent frequency weighted acceleration magnitude (~1.4 m/s2 rms) according to international standard ISO 5349 (1986). Finger circulation was measured in both the right (vibrated) and the left (non-vibrated) middle fingers before application of the vibration, and at fixed intervals during exposure to vibration and during a 45 minute recovery period.RESULTS - The FST did not change during exposure to vibration, whereas vibration with any combination of acceleration magnitude and duration produced significant percentage reductions in the FBF of the vibrated finger compared with the FBF before exposure (from 40.1% (95% confidence interval (95% CI) 24.3% to 57.2%) to 61.4% (95% CI 45.0% to 77.8%). The reduction in FBF during vibration was stronger in the vibrated finger than in the non-vibrated finger. Across the five experimental conditions, the various vibration stimuli caused a similar degree of vasoconstriction in the vibrated finger during exposure to vibration. There was a progressive decrease in the FBF of both fingers after the end of exposure to vibration with acceleration magnitudes of 44 m/s2 for 30 minutes and 62 m/s2 for 15 minutes. Significant vasoconstrictor after effects were not found in either finger after exposure to any of the other vibration stimuli with greater acceleration magnitudes for shorter durations.CONCLUSIONS - For the range of vibration magnitudes investigated (44 to 176 m/s2 rms unweighted; 5.5 to 22 m/s2 rms when frequency weighted according to ISO 5349), the vasoconstriction during exposure to 125 Hz vibration was independent of vibration magnitude. The after effect of vibration was different for stimuli with the same energy equivalent acceleration, with greater effects after longer durations of exposure. The energy equivalent acceleration therefore failed to predict the acute effects of vibration both during and after exposure to vibration. Both central and local vasoregulatory mechanisms are likely to be involved in the response of finger circulation to acute exposures to 125 Hz vibration
Recovery from COVID-19 Can Take a Long Time, Even in Young Adults with No Chronic Conditions
No full textbit.ly/MMWR71420Illustration accompanying: Tenforde MW, Kim SS, Lindsell CJ, et al. Symptom Duration and Risk Factors for Delayed Return to Usual Health Among Outpatients with COVID-19 in a Multistate Health Care Systems Network \u2014 United States, March\u2013June 2020. MMWR Morb Mortal Wkly Rep. ePub: 24 July 2020.mm6930e1_SymptomsRiskFactorsOutpatientsCOVID19_IMAGE_24July20_1200x675-medium.jp
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
1 in 2 COVID-19 Patients Could Not Identify a Person with COVID-19 with Whom They Had Close Contact in the Last 2 Weeks
No full textMany people might be getting infected in their communities.Protect yourself and others:\u2022 Limit close contact with people who don\u2019t live in your household\u2022 Wear a cloth face covering in public\u2022 Wash hands frequentlyBit.ly/MMWR63020Illustration accompanying: Tenforde MW, Rose EB, Lindsell CJ, et al. Characteristics of Adult Outpatients and Inpatients with COVID-19 \u2014 11 Academic Medical Centers, United States, March\u2013May 2020. MMWR Morb Mortal Wkly Rep. ePub: 30 June 2020..mm6926e3_OutpatientInpatientCOVID19_IMAGE_30June20_1200x675-medium.jp
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
