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61.
62.
Research productivity affects the careers of academic psychologists. Unfortunately, there is a surprising lack of consensus
on productivity’s meaning, measurement, and how to compare the productivity of one academic psychologist to another. In the
present study, we review academic productivity research within psychology, and using a sample of 673 psychologists, compute
six indexes of productivity. Most productivity metrics (publication count, citation count, or some combination of the two)
were substantially interrelated and one (Integrated Research Productivity Index) was independent from years in the field.
Female psychologists were equally as productive as male psychologists after accounting for years in the field, and pre-tenure
psychologists showed steeper change-over-time productivity slopes than post-tenure psychologists. Based on these findings,
we provide recommendations for the use and measurement of academic research productivity. 相似文献
63.
In this paper we establish the log-convexity of the rate region in 802.11 WLANs. This generalises previous results for Aloha networks and has immediate implications for optimisation based approaches to the analysis and design of 802.11 wireless networks. 相似文献
64.
Microscopic observations are made of the shear band material in three different steels: (1) an AISI 1018 cold-rolled steel
(CRS), (2) a structural steel (HY-100), and (3) an AISI 4340 vacuum arc remelted (VAR) steel tempered to either of two hardnesses,
RHC 44 or 55. To produce the shear bands, specimens were subjected to large shear strains at relatively high strain rates,
≈103/s, resulting in essentially adiabatic deformation conditions. It was found that whenever the shear band led to fracture of
the specimen, the fracture occurred by a process of void nucleation and coalescence; no cleavage was observed on any fracture
surface, including the most brittle of the steels tested (RHC = 55). This is presumably due to the softening of the shear
band material that results from the local temperature rise occurring during dynamic deformation. Differences in shear band
behavior between the various microstructures are also described.
Formerly Research Assistant, Brown University 相似文献
65.
Elahe Nezami Jennifer Unger Sylvia Tan Caitlin Mahaffey Anamara Ritt-Olson Steve Sussman Selena Nguyen-Michel Lourdes Baezconde-Garbanati Stan Azen C Anderson Johnson 《Nicotine & tobacco research》2005,7(2):243-248
Numerous studies have shown associations between smoking and depression, but the generalizability of the relationship across ethnic groups remains unknown. The present study assessed the association between depression and smoking intention and experimentation among adolescents from four ethnic groups in the Los Angeles area-Chinese/Chinese American, Latino/Hispanic, Persian/Iranian, and White. Over 800 7th graders in the Los Angeles area completed measures of depressive symptoms, experimentation with smoking, intention to smoke, and sociodemographic covariates. Chinese/Chinese American students had the lowest levels of depressive symptoms, whereas Latinos/Hispanics had the highest levels. Latinos/Hispanics also were the most likely to intend to smoke in the next year and were the most likely to have started experimenting with cigarette smoking. Depressive symptoms were significantly associated with intention to smoke even after controlling for language use acculturation, socioeconomic status, gender, and ethnicity. The association between depressive symptoms and intention to smoke did not vary significantly across ethnic groups. These results indicate that the association between depressive symptoms and adolescent smoking generalizes across diverse ethnic groups. 相似文献
66.
W. Duffy B. L. Cheng M. Gabbay G. Fantozzi 《Metallurgical and Materials Transactions A》1995,26(7):1735-1739
The internal friction (Qsu−1) and Young’s modulus (E) of BaTiO3-based ceramics were measured vs temperature from −100 °C to 150 °C. Rectangular bars of high-density (96 to 99 pct) ma-terials
were driven electrostatically in flexural vibration at a resonance frequency of about 3 kHz, at maximum strain levels of about
10−6. The curves ofQ
−1(T) andE(T) allow the study of the following three phase transformations: tetragonal to cubic (about 130 °C in pure material), orthorhombic
to tetragonal (about 0 °C in pure material), and rhombohedral to orthorhombic (about −80 °C in pure material). Internal friction
and modulus data were obtained on pure material and on materials doped with niobium and cobalt to give semiconducting and
insulating X7R behavior. Permittivity, dielectric loss, and microstructure data are given and used to aid interpretation of
the mechanical measurement data.
This article is based on a presentation given in the Mechanics and Mechanisms of Material Damping Symposium, October 1993,
in Pittsburgh, Pennsylvania, under the auspices of the SMD Physical Metallurgy Committee 相似文献
67.
68.
This article presents a meaningful, practical, and theoretically sound solution that solves the problem of grasping a rigid object with a hand that has redundant (>6) grasping contacts. This is accomplished by introducing compliance at each contact point in such a way as to provide the engineer with the capabilities of object manipulation via controlled forces at the contact points. This method of solution is adapted straight-away to compute the static forces generated in the legs of a redundant in-parallel manipulator that equilibrates a wrench applied to the moving/platform or end-effector. In a way similar to the redundant grasping problem, this is accomplished by introducing the knowledge of the compliances that exist in the legs. The solution thus obtained stems from physical parameters that model the in-parallel manipulator. The in-depth study of the duality between the statics of in-parallel manipulators and the kinematics of serial manipulators reveals a meaningful, practical, and theoretically sound solution for the inverse kinematics of a redundant serial manipulator. This is accomplished by incorporating the knowledge of the compliances that exist or are desired to exist in the joints of the manipulator. (For instance, the torsional compliance in revolute joints or the linear compliance in prismatic joints.) Such information provides a physically meaningful model of the serial manipulator that in turn yields a physically meaningful set of joint increments for a given end-effector twist. © 1992 John Wiley & Sons, Inc. 相似文献
69.
Blanchard Ray; Zucker Kenneth J.; Bradley Susan J.; Hume Caitlin S. 《Canadian Metallurgical Quarterly》1995,31(1):22
The purpose of this study was to extend the findings, previously limited to adults, that male homosexuals have a greater than average proportion of male siblings and a later than average birth order. There were 2 matched groups of 156 probands. The homosexual-prehomosexual (HP) group included boys referred to a specialty clinic because of persistent cross-gender behavior plus homosexual adolescents with or without gender identity problems. The controls were male child and adolescent patients referred for reasons other than gender identity disorder, homosexuality, or transvestism. Both predicted results were obtained in comparisons of the HP group with the controls and with expected values for the general population. Psychosocial and biological theories have been advanced to explain why male homosexuals have later births and more brothers; however, none of these is well established. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.
Moscovitch M Benevides L Romanyukha A Hull F Duffy M Voss S Velbeck KJ Nita I Rotunda JE 《Radiation protection dosimetry》2011,144(1-4):161-164
The phototransferred thermoluminescence (PTTL) technique is applied to the Harshaw LiF:Mg,Cu,P material. It is demonstrated that using 254-nm UV light, dose levels as low as 0.2 mGy can be re-estimated. The PTTL efficiency was found to be ~ 6 % in the dose range of 0.2 mGy-1 Gy, and it appears to be dose-independent. This implies that a simple calibration factor could be applied to the PTTL data for the re-estimation of dose levels. It was demonstrated that with a proper choice of the TL readout parameters, and the UV-light irradiation conditions, dose levels that are relevant to personal or environmental dosimetry can be re-estimated. 相似文献