Public Service Motivation, Role Ambiguity, and Job Satisfaction Among Municipal Police Officers

Research in public management consistently asserts that public service motivation (PSM) facilitates beneficial work behaviors and attitudes. However, few studies have been designed to examine PSM in specific occupations. Law enforcement agencies may provide unique places to examine PSM because the public benefit of policing is directly and immediately observable by officers. Yet, law enforcement occupations are highly stressful. This study attempts to connect one form of occupational stress - role ambiguity -, public service motivation, and job satisfaction in municipal police officers. Findings from a regression model indicate that the dimensions of public service motivation are important drivers of job satisfaction among police officers. Findings also suggest that minimizing occupational stress, in the form of clarifying organizational roles, plays a significant, and primary, role in shaping job satisfaction

Epiconvergence of a Sequence of Level Sums of Convex Functions

We consider the problem of minimizing the max of two convex functions from both approximation and sensitivity point of view.This lead up to study the epiconvergence of a sequence of level sums of convex functions and the related dual problems

Analyzing oral skills in voice e-mail and online interviews

This study investigated the acquisition of speaking skills in an online distance education course of 19 first semester Spanish learners. The possibility of oral development in a strictly online course was examined based on students' pronunciation production in two types of recorded speaking activities and in two real-time conversations. Students created two types of voiced audio e-mails each week during the semester: read aloud passages and grammar-drill completions. In order to determine whether students' pronunciation indeed improved over the course of the semester, their performance on these two types of audio e-mails were compared at the beginning of the semester and at the end of the semester. In addition, students participated in two Internet-mediated oral conversations with their instructor using MSN messaging at the mid-term week and final week of the semester. Three kinds of data were collected from the conversations: an articulation score (articulation = pronunciation, stress, and intonation), an accuracy score, and a proficiency score. Students' performance on these interviews provided further evidence regarding the development of their oral skills. The findings suggest that only in the area of oral proficiency were there significant gains in scores

Assessment of environmental impacts of tar releases from a biomass gasifier power plant for decentralized electricity generation

Biomass gasification systems may be relevant for decentralized power generation from recoverable agricultural and wood residues available in rural areas. Although they have many positive effects, these systems can also affect environment and human health. Indeed, during the process of biomass gasification, tars are produced and generally discharged in the local environment. This work deals with the analysis of the environmental impacts of a biomass gasifier power plant project. It compares the impacts of tar releases from the conversion of two biomasses: cotton stalks and rice husks, and that of two disposal modes (into water or on soil). The gate-to-gate environmental impacts are assessed through Life Cycle Assessment (LCA) approach. The results of this study indicate that the environmental impacts of electricity production from cotton stalks are higher than that of from rice husks. Results also show that the impact levels are high when tars are dumped into water comparatively to their discharge on soil. For environmental research, these results represent a significant step of a global environmental assessment of the studied systems

Set optimization - a rather short introduction

Recent developments in set optimization are surveyed and extended including various set relations as well as fundamental constructions of a convex analysis for set- and vector-valued functions, and duality for set optimization problems. Extensive sections with bibliographical comments summarize the state of the art. Applications to vector optimization and financial risk measures are discussed along with algorithmic approaches to set optimization problems

Around a Farkas type Lemma

The first two authors of this paper asserted in Lemma 4 of "New Farkas-type constraint qualifications in convex infinite programming" (DOI: 10.1051/cocv:2007027) that a given reverse convex inequality is consequence of a given convex system satisfying the Farkas-Minkowski constraint qualification if and only if certain set depending on the data contains a particular point of the vertical axis. This paper identifies a hidden assumption in this reverse Farkas lemma which always holds in its applications to nontrivial optimization problems. Moreover, it shows that the statement remains valid when the Farkas-Minkowski constraint qualification fails by replacing the mentioned set by its closure. This hidden assumption is also characterized in terms of the data. Finally, the paper provides some applications to convex infinite systems and to convex infinite optimization problems.Comment: 0 figure

Thermal Management of a Soft Starter: Transient Thermal Impedance Model and Performance Enhancements using Phase Change Materials

Adverse effects of starting-torque transients and high in-rush currents in induction motors are typically mitigated by employing electronically controlled soft starting voltages through silicon-controlled rectifiers (SCRs). However, the heat dissipation in the soft starter must be carefully managed in the design of motor drives. The objective of this study is both to address the heat dissipation in the soft starter by implementing analytical solutions to the heat diffusion equations inside the soft starter, and to investigate the use of a phase change material (PCM) based heat sink for thermal management of the device. The analytical modeling approach is, however, general, and can be applied to the solution of a range of thermal problems in power electronics. The transient analytical thermal model, based on the thermal quadrupole approach, allows a determination of the transient performance of a soft starter by evaluating the thyristor junction temperature. Predictions from the model are first compared to results obtained using a coupled thermal and electricalmodel based on a resistance/capacitance network approach. Experimental results obtained with the soft starter connected to a low-voltage 200 hp induction machine are then used to validate the model. Additionally, the performance improvement resulting from the use of a hybrid heat sink (plate fin heat sink immersed in a PCM) is evaluated and compared to a conventional air-cooled heat sink without a PCM under identical conditions

Fluorescent D-amino-acids reveal bi-cellular cell wall modifications important for Bdellovibrio bacteriovorous predation

Modification of essential bacterial peptidoglycan (PG) containing cell walls can lead to antibiotic resistance, for example β-lactam resistance by L,D-transpeptidase activities. Predatory Bdellovibrio bacteriovorus are naturally antibacterial and combat infections by traversing, modifying and finally destroying walls of Gram-negative prey bacteria, modifying their own PG as they grow inside prey. Historically, these multi-enzymatic processes on two similar PG walls have proved challenging to elucidate. Here, with a PG labelling approach utilizing timed pulses of multiple fluorescent D-amino acids (FDAAs), we illuminate dynamic changes that predator and prey walls go through during the different phases of bacteria:bacteria invasion. We show formation of a reinforced circular port-hole in the prey wall; L,D-transpeptidaseBd mediated D-amino acid modifications strengthening prey PG during Bdellovibrio invasion and a zonal mode of predator-elongation. This process is followed by unconventional, multi-point and synchronous septation of the intracellular Bdellovibrio, accommodating odd- and even-numbered progeny formation by non-binary division

A meta-analysis and critical review of prospective memory in autism spectrum disorder

Prospective memory (PM) is the ability to remember to carry out a planned intention at an appropriate moment in the future. Research on PM in ASD has produced mixed results. We aimed to establish the extent to which two types of PM (event-based/time-based) are impaired in ASD. In part 1, a meta-analysis of all existing studies indicates a large impairment of time-based, but only a small impairment of event-based, PM in ASD. In Part 2, a critical review concludes that time-based PM appears diminished in ASD, in line with the meta-analysis, but that caution should be taken when interpreting event-based PM findings, given potential methodological limitations of several studies. Clinical implications and directions for future research are discussed