The Influence of Race in Police–Civilian Interactions: A Content Analysis of Videotaped Interactions Taken During Cincinnati Police Traffic Stops

Although the study of police–civilian relations has recently entered the intergroup communication arena, there are no studies of actual interactions between these social categories. In part to rectify that stark omission and guided by communication accommodation theory, 313 randomly sampled video recordings from police cars on traffic stops in Cincinnati, Ohio were content analyzed. The study revealed 3 key differences as a function of the officers' and drivers' races: (a) Black drivers were more likely to experience extensive policing during the stop; (b) the communication quality of White drivers was, on average, more positive than that of the Black drivers; and (c) officers' communication behavior was more positive when the officer and driver were of the same race. These findings are consistent with public opinion data and their implications for theory are discussed.     

Calibration of MEMS-based test structures for predicting thermomechanical stress in integrated circuit interconnect structures

This paper uses a rotating-beam-sensor structure to show that the extrinsic stress from the mismatch in expansion coefficient between the aluminum and the silicon substrate dominates over the compressive stress from the sputter growth. Sintering the layers at temperatures above 150/spl deg/C reduces this compressive stress due to the action of creep. Calibration of the rotation of the device has been undertaken by direct comparison to high resolution X-ray-diffraction measurements and these show that the sensor has a resolution better than 2.8 MPa. Furthermore, we have used the sensor to investigate the variation of in-plane stress with the compliance of the intermetal dielectric, by directly comparing sensors fabricated on SiO/sub 2/ and polyimide layers.     

Work groups: From the Hawthorne studies to work teams of the 1990s and beyond.

This article summarizes the Hawthorne studies related to work groups and their legacy and traces applications of work groups and related empirical research through the 1990s. A selective review of empirical studies of work group effectiveness conducted in work settings and published in the last 20 years addresses 4 questions: (a) What identifying features have field researchers used in operationally defining work groups? (b) What research strategies have been used, and to address what kinds of questions? (c) What criteria of work group effectiveness has the field research measured, using what sources of data? (d) What variables have researchers sought to link with measures of work group effectiveness? On the basis of answers to these questions, an agenda for future research about work groups and work teams is suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

River-Ice Ecology.?II: Biological Aspects

River ice is an integral and important component of the flow regime in cold-regions environments. As demonstrated in a companion paper, it can significantly affect many of the hydrologic, geomorphic, and chemical characteristics of a river. Building on such a physical template, this paper reviews the related biological effects at all stages of winter ice cover, including the period of autumn cooling, initial freeze-up, main winter, and breakup. Special focus is placed on the role of ice in seasonal movements and avoidance behavior of fish and benthic organisms, the creation of unique in-channel and riparian habitats, the modification of aquatic and floodplain vegetation, and some river-ecology theories, including disturbance ecology and flood-pulse theory. Included is a comprehensive reference list, the most complete ever assembled on this subject.     

Instability of Thallium-Containing Superconductor Phases in Isothermal Equilibrium with Thallium Oxide

Knowledge of the equilibrium conditions under which the superconducting phases in the Tl-Ca-Ba-Cu-O system are stable would enable the controlled preparation of these materials. Isothermal equilibrium between samples in this quaternary system and Tl₂O vapor from a condensed thallium oxide source has been studied. None of the superconductor phases coexisted in equilibrium with thallium oxide under the conditions employed. Instead, two previously unknown ternary thallium-calcium-barium oxides and one previously unknown thallium-calcium oxide were observed. The equilibrium phase assemblage at temperatures between 825° and 925°C consisted of the most thallium-rich ternary oxide plus CuO, although small amounts of the other thallium-rich phases may be required to balance stoichiometry. The vapor pressure of Tl₂O established by pure, condensed thallium oxide clearly exceeds the stability limit for the superconductor phases. If the thallium-containing superconductors are stable phases at high temperature, they will exist over some range of lower Tl₂O partial pressure.     

Tobacco etch virus protease: mechanism of autolysis and rational design of stable mutants with wild-type catalytic proficiency

Because of its stringent sequence specificity, the catalyticdomain of the nuclear inclusion protease from tobacco etch virus(TEV) is a useful reagent for cleaving genetically engineeredfusion proteins. However, a serious drawback of TEV proteaseis that it readily cleaves itself at a specific site to generatea truncated enzyme with greatly diminished activity. The rateof autoinactivation is proportional to the concentration ofTEV protease, implying a bimolecular reaction mechanism. Yet,a catalytically active protease was unable to convert a catalyticallyinactive protease into the truncated form. Adding increasingconcentrations of the catalytically inactive protease to a fixedamount of the wild-type enzyme accelerated its rate of autoinactivation.Taken together, these results suggest that autoinactivationof TEV protease may be an intramolecular reaction that is facilitatedby an allosteric interaction between protease molecules. Inan effort to create a more stable protease, we made amino acidsubstitutions in the P2 and P1' positions of the internal cleavagesite and assessed their impact on the enzyme's stability andcatalytic activity. One of the P1' mutants, S219V, was not onlyfar more stable than the wild-type protease (~100-fold), butalso a more efficient catalyst.     

Could it be over so soon?

The author discusses the end of his editorial term for School Psychology Quarterly. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Groundwater salinisation on atoll islands after storm‐surge flooding: modelling the influence of central topographic depressions

Fresh groundwater lenses (FGLs) are of utmost importance for human survival on small and isolated atolls. This article examines saline damage to atoll FGLs from wave washover caused by storm surge and studies the particular influence of central topographic depressions (CTDs). We model storm surge over atoll islets of contrasting widths (400 and 800 m), both with and without CTDs of various sizes. Three key findings emerge. First, under equilibrium undisturbed conditions, the CTD slightly reduces the size of the FGL compared to atoll islets without this feature. Second, during marine flooding, prior saturated conditions at the base of a CTD impede seawater infiltration into the substrate, thereby limiting saline damage in that location. Third and most crucial, however, the amount of salt accumulated within the CTD is significant, ranging from 2 to 10 times higher than the net subsurface infiltration during the period of the storm inundation.     

Tire-wear particles as a source of zinc to the environment

Tire-tread material has a zinc (Zn) content of about 1 wt %. The quantity of tread material lost to road surfaces by abrasion has not been well characterized. Two approaches were used to assess the magnitude of this nonpoint source of Zn in the U.S. for the period 1936-1999. In the first approach, tread-wear rates from the automotive engineering literature were used in conjunction with vehicle distance-driven data from the U.S. Department of Transportation to determine Zn releases. A second approach calculated this source term from the volume of tread lost during lifetime tire wear. These analyses showed that the quantity of Zn released by tire wear in the mid-1990s was of the same magnitude as that released from waste incineration. For 1999, the quantity of Zn released by tire wear in the U.S. is estimated to be 10 000-11 000 metric tons. A specific case study focused on Zn sources and sinks in an urban-suburban watershed (Lake Anne) in the Washington, DC, metropolitan area for a time period of the late 1990s. The atmospheric flux of total Zn (wet deposition) to the watershed was 2 microg/cm2/yr. The flux of Zn to the watershed estimated from tire wear was 42 microg/cm2/yr. The measured accumulation rate of total Zn in age-dated sediment cores from Lake Anne was 27 microg/cm2/yr. These data suggest that tire-wear Zn inputs to urban-suburban watersheds can be significantly greater than atmospheric inputs, although the watershed appears to retain appreciable quantities of vehicular Zn inputs.