Factors Affecting the Output and Quit Propensities of Production Workers

We have used a proprietary data set of newly hired semi-skilled production workers at one location of a large unionized firm to investigate several issues in labor economics. This data set is unique in several respects: the workers in our sample faced the same wage schedules, had the same promotional opportunities, the same job tenure (zero), similar working conditions, and had jobs for which we were able to record their physical output. We analyze these data by formulating a simultaneous equation model to explain wages, output, education, and a worker's quit decision. The model is estimated by maximum likelihood and subjected to a variety of specification tests. Such tests include a comparison of the standard error estimates that form the basis for White's information test, and White's version of a Hausman specification test. Our principal findings are: 1. Individuals that choose more education than we would expect from their observed characteristics have lower than expected quit propensities. We argue that this low quit propensity is one of the unmeasured (and unobserved) attributes that sorting models posit are correlated with education and hence distort the usual estimates of rates of return to education. 2. The performance of non-whites in our sample was no lower than that of whites. However, on their previous jobs non-whites received lower wages than did whites. 3. The output per hour of males in our sample was higher than that of females; however, we were unable to conclude from our data whether these productivity differences could explain the higher wages received by men on their previous jobs. Moreover, this output difference may be transitory and may diminish with on-the-job learning. 4. The expected value of alternative wages had a positive (but not statistically very significant) effect on quit rates. Workers with better alternative opportunities were more likely to quit (all workers had the same opportunities on their current job). 5. Finally we found that workers with high output levels were more likely to quit than were workers with average output levels.

Increasing Process Improvement through Internet-based eBusiness Innovations

This research proposes and empirically tests a model of post adoption process improvements realized through use of partners’ Internet-based e-business applications. We identify constructs proposed within adoption and post-adoption use theoretical models as well as presented in existing inter-organizational systems research. Our analysis reveals purely organization-based factors; namely, information systems/technology infrastructure and propensity for like innovations; shape perceptions of process improvement, while technology, or innovation, based and external factors, i.e., ease of use and facilitating conditions respectively, serve as moderators of the relationships between predictors and process improvement

Geodesic Deviation in Kaluza-Klein Theories

We study in detail the equations of the geodesic deviation in multidimensional theories of Kaluza-Klein type. We show that their 4-dimensional space-time projections are identical with the equations obtained by direct variation of the usual geodesic equation in the presence of the Lorentz force, provided that the fifth component of the deviation vector satisfies an extra constraint derived here.Comment: 5 pages, Revtex, 1 figure. To appear in Phys. Rev. D (Brief Report

Using Information Technology Mindfully

Although there are numerous explanations of why users behave in specific ways toward information technologies, recent work in social psychology suggests that holistic traits such as awareness and openness are potentially important explanatory variables in technology behavior theories. In this paper, we examine the multi-dimensional construct of mindfulness and its applicability to the domain of IS research. Drawing from the social psychology literature, we adapt the notion of mindfulness and its dimensions – alertness to distinction, openness to novelty, orientation in the present, and awareness of multiple perspectives – to the domain of information systems. In doing so, we place mindfulness within the broader nomological net related to individual level decisions about information technology. Also, we present preliminary explanations for how mindfulness converges with and discriminates from existing constructs in the information systems literature. Finally, we present an initial domain-specific measure of mindfulness and assess the psychometric properties of the proposed measure. Using data collected from 318 subjects with Internet Applications as the target technology, analysis indicates that the operational measures have acceptable psychometric properties and confirmatory factor analysis supports the proposed multidimensional structure. Implications for practice and research are offered

Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores

We simulate the early stages of the evolution of turbulent, virialized, high-mass protostellar cores, with primary attention to how cores fragment, and whether they form a small or large number of protostars. Our simulations use the Orion adaptive mesh refinement code to follow the collapse from ~0.1 pc scales to ~10 AU scales, for durations that cover the main fragmentation phase, using three-dimensional gravito-radiation hydrodynamics. We find that for a wide range of initial conditions radiation feedback from accreting protostars inhibits the formation of fragments, so that the vast majority of the collapsed mass accretes onto one or a few objects. Most of the fragmentation that does occur takes place in massive, self-shielding disks. These are driven to gravitational instability by rapid accretion, producing rapid mass and angular momentum transport that allows most of the gas to accrete onto the central star rather than forming fragments. In contrast, a control run using the same initial conditions but an isothermal equation of state produces much more fragmentation, both in and out of the disk. We conclude that massive cores with observed properties are not likely to fragment into many stars, so that, at least at high masses, the core mass function probably determines the stellar initial mass function. Our results also demonstrate that simulations of massive star forming regions that do not include radiative transfer, and instead rely on a barotropic equation of state or optically thin heating and cooling curves, are likely to produce misleading results.Comment: 23 pages, 18 figures, emulateapj format. Accepted to ApJ. This version has minor typo fixes and small additions, no significant changes. Resolution of images severely degraded to fit within size limit. Download the full paper from http://www.astro.princeton.edu/~krumholz/recent.htm

Development and validation of the social thermoregulation and risk avoidance questionnaire (STRAQ-1)

Attachment theory was built around the idea that infants rely on others to survive, and it is often forgotten that survival hinged on coping with environmental demands. Adult attachment reports have instead been organized around people’s subjective experience of safety and security in relationships. To resolve the gap between infant’s physical needs and adult attachment experiences, we made a first step by developing the Social Thermoregulation and Risk Avoidance Questionnaire (STRAQ-1) in 12 countries (N = 1510), providing a complementary measure to identify biological drives formative to attachment. We conjectured that co-regulatory patterns of temperature and stress are foundational to attachment styles and on this basis used a naïve bootstrapping method to find a robust solution, conducting seven exploratory factor analyses in an exploratory-confirmatory fashion. We identified 23 (out of 57) items in 4 subscales: Social Thermoregulation (Total Omega = .83), High Temperature Sensitivity (.83), Solitary Thermoregulation (.77), and Risk Avoidance (.57). In terms of external validity, we also found that the STRAQ-1 relates to emotion regulation strategies broadly and, importantly, relates to individual differences in attachment specifically, which in turn mediates the relationship with stress and health (making the scale face valid). Our approach provides a robust first effort in identifying biological mechanisms underlying attachment formation

Did changing primary care delivery models change performance? A population based study using health administrative data

<p>Abstract</p> <p>Background</p> <p>Primary care reform in Ontario, Canada started with the introduction of new enrollment models, the two largest of which are Family Health Networks (FHNs), a capitation-based model, and Family Health Groups (FHGs), a blended fee-for-service model. The purpose of this study was to evaluate differences in performance between FHNs and FHGs and to compare performance before and after physicians joined these new primary care groups.</p> <p>Methods</p> <p>This study used Ontario administrative claims data to compare performance measures in FHGs and FHNs. The study population included physicians who belonged to a FHN or FHG for at least two years. Patients were included in the analyses if they enrolled with a physician in the two years after the physician joined a FHN or FHG, and also if they saw the physician in a two year period prior to the physician joining a FHN or FHG. Performance was derived from the administrative data, and included measures of preventive screening for cancer (breast, cervical, colorectal) and chronic disease management (diabetes, heart failure, asthma).</p> <p>Results</p> <p>Performance measures did not vary consistently between models. In some cases, performance approached current benchmarks (Pap smears, mammograms). In other cases it was improving in relation to previous measures (colorectal cancer screening). There were no changes in screening for cervical cancer or breast cancer after joining either a FHN or FHG. Colorectal cancer screening increased in both FHNs and FHGs. After enrolling in either a FHG or a FHN, prescribing performance measures for diabetes care improved. However, annual eye examinations decreased for younger people with diabetes after joining a FHG or FHN. There were no changes in performance measures for heart failure management or asthma care after enrolling in either a FHG or FHN.</p> <p>Conclusions</p> <p>Some improvements in preventive screening and diabetes management which were seen amongst people after they enrolled may be attributed to incentive payments offered to physicians within FHGs and FHNs. However, these primary care delivery models need to be compared with other delivery models and fee for service practices in order to describe more specifically what aspects of model delivery and incentives affect care.</p

Sensitivity of Present and Future Surface Temperatures to Precipitation Characteristics

A model simulation study shows that different diurnal cycles of precipitation are consistent with radically different present and future climate characteristics. In projected future climate scenarios, divergence in the time of day and type of precipitation had very divergent impacts on the radiation balance and consequently on surface temperatures. The relationship between the diurnal cycle of precipitation versus the present and future climate was examined using the GISS-MM5 (Goddard Institute for Space Studies Mesoscale Model 5) regional climate modeling system with 2 alternative moist convection schemes. June-August (JJA) mean surface temperatures of the 1990s, 2050s, and 2080s were simulated over the eastern US on a double nested 108/36 km domain, with the 36 km domain centered over the eastern US. In the 1990s, one model version simulated maxima in (convective) precipitation during the early morning, while the second model simulated the hour of precipitation maxima with considerable spatial variability (in better agreement with observations). In the futuristic climate scenarios, differences in the time of day of precipitation had very important impacts on the radiation balance at the surface. One version gave more precipitation at night and fewer clouds during the day, promoting higher surface temperatures. The alternative version created more precipitation during the day, consistent with diminished absorption of solar radiation at the surface and consequently lower surface temperatures. The results demonstrate the importance of improving cumulus parameterizations in regional mesoscale and global climate models and suggest that such improvements would lead to greater confidence in model projections of climate change

On the AC spectrum of one-dimensional random Schroedinger operators with matrix-valued potentials

We consider discrete one-dimensional random Schroedinger operators with decaying matrix-valued, independent potentials. We show that if the l^2-norm of this potential has finite expectation value with respect to the product measure then almost surely the Schroedinger operator has an interval of purely absolutely continuous (ac) spectrum. We apply this result to Schroedinger operators on a strip. This work provides a new proof and generalizes a result obtained by Delyon, Simon, and Souillard.Comment: (1 figure