Space-storable oxidizer valve Final report

Fabrication and acceptance testing, fluorine compatibility testing, valve refurbishment and testing, environmental testing, and design of space storable oxidizer valv

Traffic Stop Practices of the Iowa City Police Department: January 1 – December 31, 2002

This report summarizes the findings of a study conducted using data collected by the Iowa City Police Department between January 1 and December 31, 2002. These data resulted from 13,459 interactions between law enforcement officers and citizens during traffic-related contacts. Information was collected about the driver, the officer, and the stop event. Driver demographics included race, sex, age, residency, and vehicle registration. The only information collected about the officer was officer badge number. Finally, data collected about the stop event include the date, time of day, reason for stop, search, property seized, force, and outcome of the stop. Data analysis was conducted with the aid of SPSS-11.0 (Statistical Package for the Social Sciences). Analyses were conducted on two levels. First, descriptive analysis, using percentages, summarized stop patterns, stop characteristics, and driver demographics. Second, a program called “chisquare automatic interaction detector” or CHAID was used to evaluate the variables in terms of their relationships with one another (multivariate analysis). The greatest percentage of stops was made in the month of March (10.1%), with the fewest in June and December (6.9%). Interestingly, nearly 32% of stops occurred between midnight and 3am, with the third shift (11pm-7am) responsible for the greatest percentage (44.2%). Stopped drivers were mostly White (84%), male (63%), young (median age of 23), Iowa City residents (62%), with Iowa vehicle registrations (88%). Drivers were mainly stopped for moving violations (70%), were not searched (96%), and were released with a warning (58%). Descriptive statistics are included for a general view of the stop event and characteristics. Multivariate CHAID analyses were conducted to make inferences about the relationships among variables. CHAID segments the sample of traffic stops and reveals the interrelationship between the potential predictors and the events involved in the stop. The CHAID procedure generates a “decision tree” that identifies significant predictors of each decision in question. In effect, the procedure “crossreferences” each event with each potential predictor. Results from CHAID analyses resulted in four events (moving violation, equipment/registration violation, being warned, being arrested) with significant predictors. All four events were significantly related to the age of the driver, although different age groupings surfaced in different stop events. In addition, the sex of the driver (being male) appeared as a second order predictor in being arrested. Race of the driver never appeared as a predictor of any event. These data provide no empirical evidence that the ICPD is systematically engaging in discriminatory stop practices. Stops conducted by the Iowa City Police Department, as a whole, during the study period, do not involve the race of the driver as a significant factor related to events and outcomes. This does not mean, however, that no individual citizen ever experienced discrimination. It is always possible that individual officers may engage in racially biased practices, both in determining which drivers they will or will not stop and in determining what steps to take after the initial contact. To detect discriminatory practices at this level, however, requires constant vigilance by the community, by all the officers within the department, and by the departmental administration. Statistical analysis, while valuable, cannot substitute for community involvement and effective management. The full report notes some minor inconsistencies with the data, provides a discussion of the “baseline dilemma,” makes recommendations for the continued collection of data for future trend analysis, and suggests modifications of the data collection instrument to include more variables and to clarify some possible areas of confusion for officers who are collecting the data

Traffic Stop Practices of the Louisville Police Department: January 15 - December 31, 2001

This report summarizes the findings of a study conducted using data collected by the Louisville Division of Police between January 15, 2001 and December 31, 2001. These data resulted from 48,586 interactions between law enforcement officers and citizens during traffic-related contacts. Information was collected about the driver, the officer, and the stop event. Driver demographics included race, sex, age, residency, license number, and vehicle registration. The only information collected about the officer was officer badge number. Finally, data collected about the stop event include the date, time of day, reason for stop, activities during the stop, number of passengers, and stop outcome. Data analysis was conducted with the aid of SPSS-11.0 (Statistical Package for the Social Sciences). Analyses were conducted on two levels. First, descriptive analysis, using percentages, summarized stop patterns, stop characteristics, and driver demographics. This information is useful only to describe the existing state of affairs (what is), but not to explain them (why) or to formulate predictions about future events (what if). To address the complex relationships that exist among different variables, a program called chi-square automatic interaction detector or CHAID was used to evaluate the variables in terms of their relationships with one another (multivariate analysis). Temporally, it was not feasible to determine which month was the most active given several problems with the data on this variable. The most active time of day for stops was between 5-6pm, with 7.4% of all stops, followed by the time period from 4-5pm with 6.7% of all stops. Overall, the 2nd shift (3-11pm) was the most active, with 46% of all stops, followed by the 3rd shift (30%), and the 1st shift (24%). Stopped drivers were mostly white (64%), male (70%), between 24 and 40 years old (46%), and Louisville residents (63%). Drivers were mainly stopped for penal code violations (67%), were checked for outstanding warrants (78%), were not searched (84%), and were issued citations (67%). Drivers who were searched (17%) were searched incident to arrest (52%), and by consent (40%). About 1 in 5 searches (19%) were because of the odor of drugs or alcohol. Contraband was discovered in 31% of searches. In cases where there was a search and contraband was discovered, 74% resulted in an arrest. The descriptive analysis indicated some slight percentage differences among the races in certain events (e.g., stopped for equipment/registration violations). These percentage differences, however, cannot be used to infer correlation or causation (racial profiling). To make these types of inferences, multivariate analyses using CHAID were conducted. CHAID segments the sample of traffic stops and reveals the interrelationship between the potential predictors and the events involved in the stop. The CHAID procedure generates a decision tree that identifies significant predictors of each decision in question. In effect, the procedure cross-references each event with each potential predictor. Results from CHAID analyses resulted in five events (violation of the penal code, being asked to exit, being searched, being subject to a warrant check, and being arrested) with significant predictors. Being stopped for a penal code violation was significantly related to the race of the driver; other persons of color (72%) and whites (69%) were most likely to be stopped for this reason. Age, however, had a strong interactive effect with race. Being asked to exit, being searched, being subject to a warrant check, and being arrested all were predicted by being stopped for a misdemeanor. Driver sex also surfaced as a predictor in some situations. These data provide no empirical evidence that the LPD is systematically engaging in discriminatory stop practices. In general, stops conducted by the department, as a whole, during the study period, do not involve the race of the driver as a significant factor related to events and outcomes. The only exception to this involves stops for penal code violations, where other persons of color and whites were most likely stopped for this reason. These types of stops involve fairly low levels of officer discretion given that penal code violations are more serious than other reasons for which a driver might be stopped. This does not mean, however, that no individual citizen ever experienced discrimination. It is always possible that individual officers may engage in racially biased practices, both in determining which drivers they will or will not stop and in determining what steps to take after the initial contact. To detect discriminatory practices at this level, however, requires constant vigilance by the community, by all the officers within the department, and by the departmental administration. Statistical analysis, while valuable, cannot substitute for community involvement and effective management. The full report provides a discussion of the baseline dilemmaand makes recommendations for continued study to obtain a full year of data

Cosmic dance in the Shapley Concentration Core - I. A study of the radio emission of the BCGs and tailed radio galaxies

The Shapley Concentration ($z\approx0.048$) covers several degrees in the Southern Hemisphere, and includes galaxy clusters in advanced evolutionary stage, groups of clusters in the early stages of merger, fairly massive clusters with ongoing accretion activity, and smaller groups located in filaments in the regions between the main clusters. With the goal to investigate the role of cluster mergers and accretion on the radio galaxy population, we performed a multi-wavelength study of the BCGs and of the galaxies showing extended radio emission in the cluster complexes of Abell 3528 and Abell 3558. Our study is based on a sample of 12 galaxies. We observed the clusters with the GMRT at 235, 325 and 610 MHz, and with the VLA at 8.46 GHz. We complemented our study with the TGSS at 150 MHz, the SUMSS at 843 MHz and ATCA at 1380, 1400, 2380, and 4790 MHz data. Optical imaging with ESO-VST and mid-IR coverage with WISE are also available for the host galaxies. We found deep differences in the properties of the radio emission of the BCGs in the two cluster complexes. The BCGs in the A3528 complex and in A3556, which are relaxed cool-core objects, are powerful active radio galaxies. They also present hints of restarted activity. On the contrary, the BCGs in A3558 and A3562, which are well known merging systems, are very faint, or quiet, in the radio band. The optical and IR properties of the galaxies are fairly similar in the two complexes, showing all passive red galaxies. Our study shows remarkable differences in the radio properties of the BGCs, which we relate to the different dynamical state of the host cluster. On the contrary, the lack of changes between such different environments in the optical band suggests that the dynamical state of galaxy clusters does not affect the optical counterparts of the radio galaxies, at least over the life-time of the radio emission.Comment: 24 pages, 11 figures, accepted for publication in Astronomy & Astrophysic

Isolated Fetal Ascites Secondary to Persistent Urogenital Sinus

Objective. To present a case of isolated ascites secondary due to urogenital abnormalities (urogenital sinus) without any other prenatal ultrasound marker. Method. A 36-year-old woman with prenatal isolated ascites delivered a female baby, weighing 2.285 g; ascites was drained at birth and the baby underwent several episodes of urinary retention prior to undergoing X-ray investigations. Results. A voiding cystourethrogram revealed a short urogenital sinus: a vesicostomy was performed. A vaginoscopy revealed double vagina with a large posterior vagina. A posterior sagittal anorectal pull-through with genitoplasty was performed at 2 years old with 1-year follow-up. Conclusions. Though rare, a urogenital abnormality is to be suspected in fetal ascites cases with negative viral tests and no cardiac anomalies. The most common ultrasound marker of such abnormalities (fluid filled cavity) may be missing because of complete drainage of urine through the tubes into peritoneum

Is the treatment of the tear trough deformity with hyaluronic acid injections a safe procedure? A systematic review

Among the various therapeutic options for the treatment of tear trough deformities, the use of hyaluronic acid-based fillers has constantly been increasing. The aim of this research is to conduct a systematic review of the published literature related to the use of hyaluronic acid-based dermal fillers for the treatment of tear trough deformities and possible related complications. A search of the published literature was conducted following the PRISMA guidelines, including PubMed, Cochrane Library, and Ovid databases. Text words and Medical Search Headings (MeSH terms) were used to identify nine articles included in our analysis. The most used filler was Restylane (Galderma). The injection technique was performed through the use of a cannula or, more frequently, with a needle, through the execution of boluses or retrograde release. The injection plane was predominantly the supra-periosteal layer. The most observed side effects were mild and included redness, edema, contour irregularities, bruising, and blue-gray dyschromia. The degree of patient satisfaction was high, with an optimal aesthetic result that was maintained for 6 to 12 months. Although the duration of treatment of tear trough deformities with HA fillers is not comparable to surgical treatment, this is a minimally invasive, safe procedure, quick to perform, and with a high degree of patient satisfaction

Finite Temperature Effective Potential for Gauge Models in de Sitter Space

The one-loop effective potential for gauge models in static de Sitter space at finite temperatures is computed by means of the $\zeta$--function method. We found a simple relation which links the effective potentials of gauge and scalar fields at all temperatures. In the de Sitter invariant and zero-temperature states the potential for the scalar electrodynamics is explicitly obtained, and its properties in these two vacua are compared. In this theory the two states are shown to behave similarly in the regimes of very large and very small radii a of the background space. For the gauge symmetry broken in the flat limit ($a \to \infty$) there is a critical value of a for which the symmetry is restored in both quantum states. Moreover, the phase transitions which occur at large or at small a are of the first or of the second order, respectively, regardless the vacuum considered. The analytical and numerical analysis of the critical parameters of the above theory is performed. We also established a class of models for which the kind of phase transition occurring depends on the choice of the vacuum.Comment: 23 pages, LaTeX, 5 figure.ep

Unstable Heavy Majorana Neutrinos and Leptogenesis

We propose a new mechanism producing a non-vanishing lepton number asymmetry, based on decays of heavy Majorana neutrinos. If they are produced out of equilibrium, as occurs in preheating scenario, and are superpositions of mass eigenstates rapidly decaying, their decay rates contains interference terms provided the mass differences $\Delta m$ are small compared to widths $\Gamma$. The resulting lepton asymmetry, which is the analogue of the time-integrated CP asymmetry in $B^0-\bar{B}^0$ system, is found to be proportional to $\Delta m/\Gamma$.Comment: 18 pages, latex, revised version to be published in Phys. Rev.

Hydrodynamic electron flow in high-mobility wires

Hydrodynamic electron flow is experimentally observed in the differential resistance of electrostatically defined wires in the two-dimensional electron gas in (Al,Ga)As heterostructures. In these experiments current heating is used to induce a controlled increase in the number of electron-electron collisions in the wire. The interplay between the partly diffusive wire-boundary scattering and the electron-electron scattering leads first to an increase and then to a decrease of the resistance of the wire with increasing current. These effects are the electronic analog of Knudsen and Poiseuille flow in gas transport, respectively. The electron flow is studied theoretically through a Boltzmann transport equation, which includes impurity, electron-electron, and boundary scattering. A solution is obtained for arbitrary scattering parameters. By calculation of flow profiles inside the wire it is demonstrated how normal flow evolves into Poiseuille flow. The boundary-scattering parameters for the gate-defined wires can be deduced from the magnitude of the Knudsen effect. Good agreement between experiment and theory is obtained.Comment: 25 pages, RevTeX, 9 figure