221 research outputs found
A Bibliometric Study of Authorship and Collaboration Trends Over the Past 30 Years in Four Major Musculoskeletal Science Journals
This study explored changes in bibliometric variables over the last 30 years for four major musculoskeletal science journals (BONE®), Calcified Tissue International® (CTI®), Journal of Bone and Mineral Research® (JBMR®), and Journal of Orthopaedic Research® (JOR®), with a specific focus on author gender. Bibliometric data were collected for all manuscripts in 1985 (BONE®, CTI®, JOR®), 1986 (JBMR®), 1995, 2005, and 2015; 2776 manuscripts met inclusion criteria. Manuscripts from Europe were more often published in BONE® or CTI®, while those from North America in JBMR® or JOR®. All journals demonstrated an increase over time in the number of authors (3.67–7.3), number of countries (1.1–1.4), number of institutions (1.4–3.1), and number of references (25.1–45.4). The number of manuscript pages increased (6.6–8.9) except for JOR® which showed a decline. CTI® had the lowest number of authors (4.9 vs. 5.6–6.8). There was a change in the corresponding author position from first to last for all journals; this change was highest for CTI® (35%) and lowest for BONE® (14.0%). All journals demonstrated an increase over time in female authors; however, CTI® was the highest amongst these four journals. The percentage of female first authors rose from 24.6 to 44.3% (CTI® 29.1–52.3%). The percentage of corresponding female authors rose from 17.5 to 33.6% (CTI® 22.9–40.0%). The proportion of female authors is increasing, likely reflecting the increasing number of women obtaining doctorates in science, medicine, and engineering
Temperature dependence of mechanical stiffness and dissipation in ultrananocrystalline diamond
Ultrananocrystalline diamond (UNCD) films are promising for radio frequency micro electro mechanical systems (RF-MEMS) resonators due to the extraordinary physical properties of diamond, such as high Young’s modulus, quality factor, and stable surface chemistry. UNCD films used for this study are grown on 150 mm silicon wafers using hot filament chemical vapor deposition (HFCVD) at 680°C. UNCD fixed free (cantilever) resonator structures designed for the resonant frequencies in the kHz range have been fabricated using conventional microfabrication techniques and are wet released. Resonant excitation and ring down measurements in the temperature range of 138 K to 300 K were conducted under ultra high vacuum (UHV) conditions in a custom built UHV AFM stage to determine the temperature dependence of Young’s Modulus and dissipation (quality factor) in these UNCD cantilever structures. We measured a temperature coefficient of frequency (TCF) of 121 and 133 ppm/K for the cantilevers of 350 ìm and 400 ìm length respectively. Young’s modulus of the cantilevers increased by about 3.1% as the temperature was reduced from 300 K to 138 K. This is the first such measurement for UNCD and suggests that the nanostructure plays a significant role in modifying the thermo-mechanical response of the material. The quality factor of these resonators showed a moderate increase as the cantilevers were cooled from 300 K to 138 K. The results suggest that surface and bulk defects significantly contribute to the observed dissipation in UNCD resonators
Mechanical stiffness and dissipation in ultrananocrystalline diamond microresonators
We have characterized mechanical properties of ultrananocrystalline diamond UNCD thin films grown using the hot filament chemical vapor deposition HFCVD technique at 680 °C, significantly lower than the conventional growth temperature of 800 °C. The films have 4.3% sp2 content in the near-surface region as revealed by near edge x-ray absorption fine structure spectroscopy. The films, 1 m thick, exhibit a net residual compressive stress of 3701 MPa averaged over the entire 150 mm wafer. UNCD microcantilever resonator structures and overhanging ledges were fabricated using lithography, dry etching, and wet release techniques. Overhanging ledges of the films released from the substrate exhibited periodic undulations due to stress relaxation. This was used to determine a biaxial modulus of 8382 GPa. Resonant excitation and ring-down measurements in the kHz frequency range of the microcantilevers were conducted under ultrahigh vacuum UHV conditions in a customized UHV atomic force microscope system to determine Young’s modulus as well as mechanical dissipation of cantilever structures at room temperature. Young’s modulus is found to be 79030 GPa. Based on these measurements, Poisson’s ratio is estimated to be 0.0570.038. The quality factors Q of these resonators ranged from 5000 to 16000. These Q values are lower than theoretically expected from the intrinsic properties of diamond. The results indicate that surface and bulk defects are the main contributors to the observed dissipation in UNCD resonators
Progressive skeletal benefits of physical activity when young as assessed at the midshaft humerus in male baseball players
Physical activity benefits the skeleton, but there is contrasting evidence regarding whether benefits differ at different stages of growth. The current study demonstrates that physical activity should be encouraged at the earliest age possible and be continued into early adulthood to gain most skeletal benefits.
INTRODUCTION:
The current study explored physical activity-induced bone adaptation at different stages of somatic maturity by comparing side-to-side differences in midshaft humerus properties between male throwing athletes and controls. Throwers present an internally controlled model, while inclusion of control subjects removes normal arm dominance influences.
METHODS:
Throwing athletes (n = 90) and controls (n = 51) were categorized into maturity groups (pre, peri, post-early, post-mid, and post-late) based on estimated years from peak height velocity (10 years). Side-to-side percent differences in midshaft humerus cortical volumetric bone mineral density (Ct.vBMD) and bone mineral content (Ct.BMC); total (Tt.Ar), medullary (Me.Ar), and cortical (Ct.Ar) areas; average cortical thickness (Ct.Th); and polar Strength Strain Index (SSIP) were assessed.
RESULTS:
Significant interactions between physical activity and maturity on side-to-side differences in Ct.BMC, Tt.Ar, Ct.Ar, Me.Ar, Ct.Th, and SSIP resulted from the following: (1) greater throwing-to-nonthrowing arm differences than dominant-to-nondominant arm differences in controls (all p < 0.05) and (2) throwing-to-nonthrowing arm differences in throwers being progressively greater across maturity groups (all p < 0.05). Regional analyses revealed greatest adaptation in medial and lateral sectors, particularly in the three post-maturity groups. Years throwing predicted 59% of the variance of the variance in throwing-to-nonthrowing arm difference in SSIP (p < 0.001).
CONCLUSION:
These data suggest that physical activity has skeletal benefits beginning prior to and continuing beyond somatic maturation and that a longer duration of exposure to physical activity has cumulative skeletal benefits. Thus, physical activity should be encouraged at the earliest age possible and be continued into early adulthood to optimize skeletal benefits
[Introduction] Toward an anthropology of the just price: history, ethnography, critique
No description supplie
Bibliometric Analysis of Female Authorship Trends and Collaboration Dynamics Over JBMR's 30-Year History
In academia, authorship is considered a currency and is important for career advancement. As the Journal of Bone and Mineral Research (JBMR) is the highest-ranked journal in the field of bone, muscle, and mineral metabolism and is the official publication of the American Society for Bone and Mineral Research, we sought to examine authorship changes over JBMR's 30-year history. Two bibliometric methods were used to collect the data. The “decade method” included all published manuscripts throughout 1 year in each decade over the past 30 years starting with the inaugural year, yielding 746 manuscripts for analysis. The “random method” examined 10% of published manuscripts from each of the 30 years, yielding 652 manuscripts for analysis. Using both methods, the average number of authors per manuscript, numerical location of the corresponding author, number of collaborating institutions, number of collaborating countries, number of printed manuscript pages, and the number of times each manuscript was cited all significantly increased between 1986 and 2015 (p < 10−4). Using the decade method, there was a significant increase in the percentage of female first authors over time from 35.8% in 1986 to 47.7% in 2015 (p = 0.02), and this trend was confirmed using the random method. The highest percentage of female first authors in 2015 was in Europe (60.0%), and Europe also had the most dramatic increase in female first authors over time (more than double in 2015 compared with 1986). Likewise, the overall number of female corresponding authors significantly increased during the past 30 years. With the increasing demands of publishing in academic medicine, understanding changes in publishing characteristics over time and by geographical region is important. These findings highlight JBMR's authorship trends over the past 30 years and demonstrate those countries having the most changes and where challenges still exist
Broadband velocity modulation spectroscopy of HfF^+: towards a measurement of the electron electric dipole moment
Precision spectroscopy of trapped HfF^+ will be used in a search for the
permanent electric dipole moment of the electron (eEDM). While this dipole
moment has yet to be observed, various extensions to the standard model of
particle physics (such as supersymmetry) predict values that are close to the
current limit. We present extensive survey spectroscopy of 19 bands covering
nearly 5000 cm^(-1) using both frequency-comb and single-frequency laser
velocity-modulation spectroscopy. We obtain high-precision rovibrational
constants for eight electronic states including those that will be necessary
for state preparation and readout in an actual eEDM experiment.Comment: 13 pages, 7 figures, 3 table
Towards a synthesized critique of neoliberal biodiversity conservation
During the last three decades, the arena of biodiversity conservation has largely aligned itself with the globally dominant political ideology of neoliberalism and associated governmentalities. Schemes such as payments for ecological services are promoted to reach the multiple ‘wins’ so desired: improved biodiversity conservation, economic development, (international) cooperation and poverty alleviation, amongst others. While critical scholarship with respect to understanding the linkages between neoliberalism, capitalism and the environment has a long tradition, a synthesized critique of neoliberal conservation - the ideology (and related practices) that the salvation of nature requires capitalist expansion - remains lacking. This paper aims to provide such a critique. We commence with the assertion that there has been a conflation between ‘economics’ and neoliberal ideology in conservation thinking and implementation. As a result, we argue, it becomes easier to distinguish the main problems that neoliberal win-win models pose for biodiversity conservation. These are framed around three points: the stimulation of contradictions; appropriation and misrepresentation and the disciplining of dissent. Inspired by Bruno Latour’s recent ‘compositionist manifesto’, the conclusion outlines some ideas for moving beyond critique
Pecunia non olet but does rose money smell?: on rose oil prices and moral economy in Isparta, Turkey
Market, morality and (just) price: the case of recycling economy in Turkey
By drawing on ethnographic fieldwork conducted amongst waste-pickers and recycling traders in the waste paper, plastic and scrap metal sectors, and engaging with literature from economic anthropology and history, as well as archival sources, this paper documents changing perceptions of just price, morality and fairness in the Turkish recycling market. The paper suggests that multiple markets imply multiple prices, which are contingent and contested. When dealing with price mechanisms largely outside their control, actors tend to associate a fair price with the going market price, rather than factors such as state regulation. Approaches to morality and assessments of fairness become more ambiguous when prices are mediated by actors? own practices. These range from gift relations to paternalism, envy and deception
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