Use of implicit graph for recommending relevant videos: a simulated evaluation

In this paper, we propose a model for exploiting community based usage information for video retrieval. Implicit usage information from a pool of past users could be a valuable source to address the difficulties caused due to the semantic gap problem. We propose a graph-based implicit feedback model in which all the usage information can be represented. A number of recommendation algorithms were suggested and experimented. A simulated user evaluation is conducted on the TREC VID collection and the results are presented. Analyzing the results we found some common characteristics on the best performing algorithms, which could indicate the best way of exploiting this type of usage information

National level promotion of physical activity: results from England's ACTIVE for LIFE campaign.

STUDY OBJECTIVE: To assess the impact of a national campaign on awareness of the campaign, change in knowledge of physical activity recommendations and self reported physical activity. DESIGN: three year prospective longitudinal survey using a multi-stage, cluster random probability design to select participants. SETTING: England. PARTICIPANTS: A nationally representative sample of 3189 adults aged 16-74 years. MAIN OUTCOME MEASURES: Awareness of the advertising element of the campaign, changes in knowledge of physical activity recommendations for health and self reported physical activity. RESULTS: 38% of participants were aware of the main advertising images, assessed six to eight months after the main television advertisement. The proportion of participants knowledgeable about moderate physical activity recommendations increased by 3.0% (95% CI: 1.4%, 4.5%) between waves 1 and 2 and 3.7% (95% CI: 2.1%, 5.3%) between waves 1 and 3. The change in proportion of active people between baseline and waves 1 and 2 was -0.02 (95% CI: -2.0 to +1.7) and between waves 1 and 3 was -9.8 (-7.9 to -11.7). CONCLUSION: The proportion of participants who were knowledgeable about the new recommendations, increased significantly after the campaign. There was however, no significant difference in knowledge by awareness of the main campaign advertisement. There is no evidence that ACTIVE for LIFE improved physical activity, either overall or in any subgroup

Wildlife-livestock interactions and risk areas for cross-species spread of bovine tuberculosis

The transmission of diseases between livestock and wildlife can be a hindrance to effective disease control. Maintenance hosts and contact rates should be explored to further understand the transmission dynamics at the wildlife-livestock interface. Bovine tuberculosis (BTB) has been shown to have wildlife maintenance hosts and has been confirmed as present in the African buffalo (Syncerus caffer) in the Queen Elizabeth National Park (QENP) in Uganda since the 1960s. The first aim of this study was to explore the spatio-temporal spread of cattle illegally grazing within the QENP recorded by the Uganda Wildlife Authority (UWA) rangers in a wildlife crime database. Secondly, we aimed to quantify wildlife-livestock interactions and cattle movements, on the border of QENP, using a longitudinal questionnaire completed by 30 livestock owners. From this database, 426 cattle sightings were recorded within QENP in 8 years. Thirteen (3.1%) of these came within a 300 m–4 week space-time window of a buffalo herd, using the recorded GPS data. Livestock owners reported an average of 1.04 (95% CI 0.97–1.11) sightings of Uganda kob, waterbuck, buffalo or warthog per day over a 3-month period, with a rate of 0.22 (95% CI 0.20–0.25) sightings of buffalo per farmer per day. Reports placed 85.3% of the ungulate sightings and 88.0% of the buffalo sightings as further than 50 m away. Ungulate sightings were more likely to be closer to cattle at the homestead (OR 2.0, 95% CI 1.1–3.6) compared with the grazing area. Each cattle herd mixed with an average of five other cattle herds at both the communal grazing and watering points on a daily basis. Although wildlife and cattle regularly shared grazing and watering areas, they seldom came into contact close enough for aerosol transmission. Between species infection transmission is therefore likely to be by indirect or non-respiratory routes, which is suspected to be an infrequent mechanism of transmission of BTB. Occasional cross-species spillover of infection is possible, and the interaction of multiple wildlife species needs further investigation. Controlling the interface between wildlife and cattle in a situation where eradication is not being considered may have little impact on BTB disease control in cattle

Identifying auditor stopping rules in decision making under uncertainty

A stopping rule is a mechanism whereby the decision maker chooses to stop the search for information and make a decision (Gigerenzer and Selten 2001). This study analyses rich verbal protocol data provided by experienced auditors completing a detailed risk identification case to increase our understanding how stopping rules are applied by auditors, the impact of different stopping rules on judgment performance, and the influence of taskspecific experience and the availability of a decision aid on the relationship between stopping rules and performance. The results revealed that while auditors use a combination of stopping rules, those rules involving the development of a mental model of the client were generally favoured and led to superior performance. Participants generally ignored a decision aid checklist that was made available as a structured alternative to their own stopping rule

Laser frequency locking by direct measurement of detuning

We present a new method of laser frequency locking in which the feedback signal is directly proportional to the detuning from an atomic transition, even at detunings many times the natural linewidth of the transition. Our method is a form of sub-Doppler polarization spectroscopy, based on measuring two Stokes parameters ($I_2$ and $I_3$) of light transmitted through a vapor cell. This extends the linear capture range of the lock loop by up to an order of magnitude and provides equivalent or improved frequency discrimination as other commonly used locking techniques.Comment: 4 pages, 4 figures Revte

Synchronization and oscillatory dynamics in heterogeneous mutually inhibited neurons

We study some mechanisms responsible for synchronous oscillations and loss of synchrony at physiologically relevant frequencies (10-200 Hz) in a network of heterogeneous inhibitory neurons. We focus on the factors that determine the level of synchrony and frequency of the network response, as well as the effects of mild heterogeneity on network dynamics. With mild heterogeneity, synchrony is never perfect and is relatively fragile. In addition, the effects of inhibition are more complex in mildly heterogeneous networks than in homogeneous ones. In the former, synchrony is broken in two distinct ways, depending on the ratio of the synaptic decay time to the period of repetitive action potentials ($\tau_s/T$), where $T$ can be determined either from the network or from a single, self-inhibiting neuron. With $\tau_s/T > 2$, corresponding to large applied current, small synaptic strength or large synaptic decay time, the effects of inhibition are largely tonic and heterogeneous neurons spike relatively independently. With $\tau_s/T < 1$, synchrony breaks when faster cells begin to suppress their less excitable neighbors; cells that fire remain nearly synchronous. We show numerically that the behavior of mildly heterogeneous networks can be related to the behavior of single, self-inhibiting cells, which can be studied analytically.Comment: 17 pages, 6 figures, Kluwer.sty. Journal of Compuational Neuroscience (in press). Originally submitted to the neuro-sys archive which was never publicly announced (was 9802001