Regulating Access to Adult Content (with Privacy Preservation)

In the physical world we have well-established mechanisms for keeping children out of adult-only areas. In the virtual world this is generally replaced by self declaration. Some service providers resort to using heavy-weight identification mechanisms, judging adulthood as a side effect thereof. Collection of identification data arguably constitutes an unwarranted privacy invasion in this context, if carried out merely to perform adulthood estimation. This paper presents a mechanism that exploits the adult's more extensive exposure to public media, relying on the likelihood that they will be able to recall details if cued by a carefully chosen picture. We conducted an online study to gauge the viability of this scheme. With our prototype we were able to predict that the user was a child 99% of the time. Unfortunately the scheme also misclassified too many adults. We discuss our results and suggest directions for future research

The impact of realistic models of mass segregation on the event rate of extreme-mass ratio inspirals and cusp re-growth

One of the most interesting sources of gravitational waves (GWs) for LISA is the inspiral of compact objects on to a massive black hole (MBH), commonly referred to as an "extreme-mass ratio inspiral" (EMRI). The small object, typically a stellar black hole (bh), emits significant amounts of GW along each orbit in the detector bandwidth. The slowly, adiabatic inspiral of these sources will allow us to map space-time around MBHs in detail, as well as to test our current conception of gravitation in the strong regime. The event rate of this kind of source has been addressed many times in the literature and the numbers reported fluctuate by orders of magnitude. On the other hand, recent observations of the Galactic center revealed a dearth of giant stars inside the inner parsec relative to the numbers theoretically expected for a fully relaxed stellar cusp. The possibility of unrelaxed nuclei (or, equivalently, with no or only a very shallow cusp) adds substantial uncertainty to the estimates. Having this timely question in mind, we run a significant number of direct-summation $N-$body simulations with up to half a million particles to calibrate a much faster orbit-averaged Fokker-Planck code. We then investigate the regime of strong mass segregation (SMS) for models with two different stellar mass components. We show that, under quite generic initial conditions, the time required for the growth of a relaxed, mass segregated stellar cusp is shorter than a Hubble time for MBHs with $M_\bullet \lesssim 5 \times 10^6 M_\odot$ (i.e. nuclei in the range of LISA). SMS has a significant impact boosting the EMRI rates by a factor of $\sim 10$ for our fiducial models of Milky Way type galactic nuclei.Comment: Accepted by CQG, minor changes, a bit expande

Temperature Dependence of Exciton Diffusion in Conjugated Polymers

The temperature dependence of the exciton dynamics in a conjugated polymer is studied using time-resolved spectroscopy. Photoluminescence decays were measured in heterostructured samples containing a sharp polymer-fullerene interface, which acts as an exciton quenching wall. Using a 1D diffusion model, the exciton diffusion length and diffusion coefficient were extracted in the temperature range of 4-293 K. The exciton dynamics reveal two temperature regimes: in the range of 4-150 K, the exciton diffusion length (coefficient) of ~3 nm (~1.5 × 10-4 cm2/s) is nearly temperature independent. Increasing the temperature up to 293 K leads to a gradual growth up to 4.5 nm (~3.2 × 10-4 cm2/s). This demonstrates that exciton diffusion in conjugated polymers is governed by two processes: an initial downhill migration toward lower energy states in the inhomogenously broadened density of states, followed by temperature activated hopping. The latter process is switched off below 150 K.

Empirical game theory of pedestrian interaction for autonomous vehicles

Autonomous vehicles (AV’s) are appearing on roads, based on standard robotic mapping and navigation algorithms. However their ability to interact with other road-users is much less well understood. If AVs are programmed to stop every time another road user obstructs them, then other road users simply learn that they can take priority at every interaction, and the AV will make little or no progress. This issue is especially important in the case of a pedestrian crossing the road in front of the AV. The present methods paper expands the sequential chicken model introduced in (Fox et al., 2018), using empirical data to measure behavior of humans in a controlled plus-maze experiment, and showing how such data can be used to infer parameters of the model via a Gaussian Process. This providing a more realistic, empirical understanding of the human factors intelligence required by future autonomous vehicles

Do Athlete and Coach Performance Perfectionism Predict Athlete Burnout?

Research has illustrated that athlete perfectionism predicts athlete burnout. The present study sought to build on existing research in two ways. First, we provide the first test of the relationship between performance perfectionism and athlete burnout. That is, whether the degree to which athlete’s expect their own or others’ sport performances to be perfect, predicts burnout. Second, we broaden the examination of the perfectionism-burnout relationship to include coaches by testing the incremental predictive ability of perceptions of coach other-oriented performance perfectionism (the degree to which coaches were perceived to expect perfect performances from others). A sample of 190 competitive adult athletes (M age = 20.54) completed measures of their own performance perfectionism (self-oriented, socially prescribed, and other-oriented performance perfectionism), perceived coach other-oriented performance perfectionism, and burnout symptoms. Regression analyses indicated that both athlete self-oriented and socially prescribed performance perfectionism positively predicted athlete burnout. In addition, after controlling for all dimensions of athlete performance perfectionism, perceived coach other-oriented performance perfectionism positively predicted athlete burnout. The findings suggest that, in addition to their own perfectionism, when athletes perceive their coaches to be more perfectionistic towards others, they are more likely to experience burnout

Perfectionism and Burnout in Athletes: The Mediating Role of Perceived Stress

Perfectionism is a consistent predictor of athlete burnout. Researchers have therefore sought to examine the psychological mechanisms that may explain this relationship. In the present study, guided by Smith’s cognitive-affective stress model, we extend existing research by examining whether perceived stress is one such explanatory factor. A sample of 256 adult athletes completed measures of perfectionism (perfectionistic strivings and perfectionistic concerns), perceived stress, and burnout. Correlational analyses indicated that perfectionistic concerns was positively related to burnout, while perfectionistic strivings was either negatively related or unrelated to burnout. Tests of bias-corrected bootstrapped indirect effects showed that perceived stress mediated the positive relationship between perfectionistic concerns and burnout. This finding was evident when examining total burnout and all three burnout symptoms. It appears that athletes high in perfectionistic concerns are likely to experience heightened levels of stress in sport which may in turn render them more vulnerable to burnout

Accounting students' IT applicaton skills over a 10-year period

This paper reports on the changing nature of a range of information technology (IT) application skills that students declare on entering an accounting degree over the period from 1996 to 2006. Accounting educators need to be aware of the IT skills students bring with them to university because of the implications this has for learning and teaching within the discipline and the importance of both general and specific IT skills within the practice and craft of accounting. Additionally, IT skills constitute a significant element within the portfolio of employability skills that are increasingly demanded by employers and emphasized within the overall Higher Education (HE) agenda. The analysis of students' reported IT application skills on entry to university, across a range of the most relevant areas of IT use in accounting, suggest that their skills have continued to improve over time. However, there are significant differential patterns of change through the years and within cohorts. The paper addresses the generalizability of these findings and discusses the implications of these factors for accounting educators, including the importance of recognising the differences that are potentially masked by the general increase in skills; the need for further research into the changing nature, and implications, of the gender gap in entrants' IT application skills; and the low levels of entrants' spreadsheet and database skills that are a cause for concern

A biophysical model of prokaryotic diversity in geothermal hot springs

Recent field investigations of photosynthetic bacteria living in geothermal hot spring environments have revealed surprisingly complex ecosystems, with an unexpected level of genetic diversity. One case of particular interest involves the distribution along hot spring thermal gradients of genetically distinct bacterial strains that differ in their preferred temperatures for reproduction and photosynthesis. In such systems, a single variable, temperature, defines the relevant environmental variation. In spite of this, each region along the thermal gradient exhibits multiple strains of photosynthetic bacteria adapted to several distinct thermal optima, rather than the expected single thermal strain adapted to the local environmental temperature. Here we analyze microbiology data from several ecological studies to show that the thermal distribution field data exhibit several universal features independent of location and specific bacterial strain. These include the distribution of optimal temperatures of different thermal strains and the functional dependence of the net population density on temperature. Further, we present a simple population dynamics model of these systems that is highly constrained by biophysical data and by physical features of the environment. This model can explain in detail the observed diversity of different strains of the photosynthetic bacteria. It also reproduces the observed thermal population distributions, as well as certain features of population dynamics observed in laboratory studies of the same organisms

<em>Marichromatium indicum</em> sp. nov., a new purple sulfur Gammaproteobacterium from mangroves of Goa, India

A reddish-brown bacterium was isolated from photoheterotrophic enrichments of mangrove soil from the western coast of India, in a medium that contained 10 % (w/v) NaCl. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA100T clusters with species of the genus Marichromatium of the class ‘Gammaproteobacteria’. Cells of strain JA100T are Gram-negative, motile rods with monopolar single flagella; they require NaCl, the optimum concentration being 1–4 %, and tolerate concentrations up to 13 %. The strain has vesicular internal membrane structures, bacteriochlorophyll a and, most probably, carotenoids of the spirilloxanthin series. No growth factors are required. A reduced sulfur source is required for growth, and, during growth on reduced sulfur sources as electron donors, sulfur is intermediately deposited as a single large granule within the cell. Strain JA100T could not grow at the expense of other tricarboxylic acid cycle intermediates, except malate. On the basis of 16S rRNA gene sequence analysis and its morphological and physiological characteristics, strain JA100T is sufficiently different from other Marichromatium species to justify its designation as a novel species, for which the name Marichromatium indicum sp. nov. is proposed. The type strain is JA100T (=DSM 15907T=ATCC BAA-741T=JCM 12653T)

Factorial validity and measurement invariance of the Athlete Burnout Questionnaire (ABQ).

The Athlete Burnout Questionnaire (ABQ) is the gold standard measure for burnout in athletes. However, previous assessments of factorial validity have: (a) tested overly restrictive measurement models; (b) provided mixed support for factorial validity; and (c) not been applied to assess measurement invariance across gender, sport type, or age. To address these issues, we used ABQ data provided by 914 athletes (Mage = 21.75 years, SD = 8.79) and examined factorial validity using confirmatory factor analysis (CFA) and exploratory structural equation modelling (ESEM) techniques. We also examined measurement invariance of the ABQ data across reported gender (female, male), sport type (individual, team), and age (≤18 years, >18 years) groups. The analyses revealed that an ESEM model provided superior fit over the corresponding CFA model. In terms of measurement invariance, support was provided for the equivalence of the ABQ across each group. This means that researchers using the ABQ can collect data across these groups and examine potential differences with confidence that the ABQ is approximately invariant. In all, we provide evidence that the majority of ABQ items are key target construct indicators and the burnout construct (as measured by the ABQ) has the same structure and meaning to different athlete groups