Reranking web search results for diversity

Search engine results are often biased towards a certain aspect of a query or towards a certain meaning for ambiguous query terms. Diversification of search results offers a way to supply the user with a better balanced result set increasing the probability that a user finds at least one document suiting her information need. In this paper, we present a reranking approach based on minimizing variance of Web search results to improve topic coverage in the top-k results. We investigate two different document representations as the basis for reranking. Smoothed language models and topic models derived by Latent Dirichlet?allocation. To evaluate our approach we selected 240 queries from Wikipedia disambiguation pages. This provides us with ambiguous queries together with a community generated balanced representation of their (sub)topics. For these queries we crawled two major commercial search engines. In addition, we present a new evaluation strategy based on Kullback-Leibler divergence and Wikipedia. We evaluate this method using the TREC sub-topic evaluation on the one hand, and manually annotated query results on the other hand. Our results show that minimizing variance in search results by reranking relevant pages significantly improves topic coverage in the top-k results with respect to Wikipedia, and gives a good overview of the overall search result. Moreover, latent topic models achieve competitive diversification with significantly less reranking. Finally, our evaluation reveals that our automatic evaluation strategy using Kullback-Leibler divergence correlates well with α-nDCG scores used in manual evaluation efforts.     

A longitudinal assessment of adolescent student-athletes’ school performance

In Germany, extraordinarily talented student-athletes are offered the special school setting of elite schools of sport (ESSs). These schools seek to optimally adjust the daily affordances of athletic high-performance training with those of regular school education. The aim of the present analysis was to empirically explore whether elite student-athletes’ school grades develop differently than those of fellow students who dropped out of the ESS’s athletic program. One cohort of student-athletes (N?=?260) was tracked from the moment of their enrollment in the ESS until the end of lower secondary school (from school level 7 to 10). Multilevel modeling was used to analyze this longitudinal dataset. Elite student-athletes who manage to still meet their school’s athletic standards after class level 10 (n?=?158) came to their ESSs with better school grades in mathematics and German from primary school than program dropouts (n?=?102). Additional comparisons show that after class level 10, all ESS students’ school grades in mathematics and German were not significantly different from the federal state’s general average at schools without high-performance sport programs. Findings are interpreted against the background of the hypothesis that the system of high-performance sports tends to produce an instance of total commitment and that educational disadvantages for ESS student-athletes could follow as a consequence.     

Linking the components of a university program to the qualification profile of graduates: The case of a sustainability‐oriented environmental science curriculum

A university Environmental Sciences curriculum is described against the background of requirements for environmental problem solving for sustainability and then analyzed using data from regular surveys of graduates (N = 373). Three types of multiple regression models examine links between qualifications and curriculum components in order to derive some conclusions about which qualifications are enhanced by which curriculum components. The underlying rationale of these models is that assessments of the importance of a certain component (and the time graduates think should be allocated to it) should increase with the workplace demand for the qualifications it provides. A comprehensive set of 19 qualifications was used, subdivided into three areas of environmental problem‐solving skills (A, basic scientific and technological skills; B, transformation‐oriented skills; and C, sociopolitical skills) and two areas of transferable skills (D, individual key skills and E, social and communication skills). Relationships identified by different regression models are discussed in terms of mutual consistency and with regard to the design, content, and learning goals of the curriculum components. Many plausible relationships were identified. Using such regression models is a promising indirect method that may be generally applicable for the explorative qualification‐oriented evaluation of university curricula and their fundamental components based on graduates' judgments. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 537–569, 2009     

Does inside passing contribute to the high incidence of groin injuries in soccer? A biomechanical analysis

Groin injuries are common in soccer and often cause time-loss from training. While groin injuries have been linked to full effort kicking, the role of inside passing is unclear. Therefore, the purpose of this study was to investigate hip joint kinematics and muscle force, stress and contraction velocity for adductor longus and gracilis during inside passing. 3D kinematics of ten soccer players (23.4 yrs; 77.5 kg; 1.81 m) were captured with a motion capture system inside a Footbonaut. Muscle force and contraction velocity were determined with AnyBody Modelling System. Gracilis muscle forces were 9% lower compared to adductor longus (p = 0.005), but muscle stress was 183% higher in gracilis (p = 0.005). Contraction velocity reveals eccentric contraction of gracilis in the last quarter of the swing phase. Considering the combination of eccentric contraction, high muscle stress and the repetitive nature of inside passing, gracilis accumulates high loads in matches and training. These results indicate that the high incidence of groin injuries in soccer could be linked to isolated pass training. Practitioners need to be aware of the risk and refrain from sudden increases in the amount of pass training. This gives the musculoskeletal system time to adapt and might avoid career threatening injuries.     

Fortune is fickle: null-effects of disfluency on learning outcomes

Recently, Diemand-Yauman et al. Cognition, 118, 114–118 (2011) demonstrated that learning with disfluent (hard-to-read) materials is more effective than learning with easy-to-read materials – a study that has since stipulated a number of follow-up studies (with mixed results). However, there is a potential confound in the original experiments: The disfluent materials were not only disfluent but also rather unusual. Therefore, they might have been particularly distinctive and have attracted more attention, which then resulted in better learning. We conducted three experiments to address this confound, all of them slightly modified replications of Diemand-Yauman et al.’s Experiment 1. Participants received five lists, either at their own pace on a computer screen (Experiment 1) or experimenter-paced on paper (Experiments 2 & 3). In Experiments 1 and 2, participants either received one fluent and four disfluent lists or they received four fluent lists and one disfluent list. The position of the distinct list varied across participants. In Experiment 3, the distinct list was always the penultimate one. In none of the experiments, learning performance was affected by any of the experimental manipulations. Our results question the generality of the disfluency effect with respect to learning.     

Diagnosing Decay Mechanisms at the Porta Nocera Necropolis,Pompeii: The First Step Towards Effective Preventive Conservation

ABSTRACT

Aspects of preventive conservation are central to the long-term preservation of archaeological sites such as Pompeii. Mitigating moisture ingress and its manifold effects on decay mechanisms such as salt degradation are of critical importance when planning durable conservation strategies. A suite of non-destructive techniques was used to diagnose decay mechanisms at an ancient tomb monument at the Porta Nocera Necropolis. Rising damp and salt contamination are shown to be actively contributing to on-going deterioration of the plaster surfaces. An existing shelter is shown to be inadequate in its protection. These initial results are used to inform a more in-depth, long-term survey as well as the design of a holistic preventive strategy.     

Erwartungshaltungen von Sekundärschullehrern in Nairobi

This article analyses the factors influencing the attitude of secondary school teachers in Nairobi. The findings are based on data collected in a three months field study. 30 interviews supplemented by questionnaires and observation show that due to the principle of equal pay for equal work the younger male teachers suffer from relative deprivation in status and are therefore the least motivated and the most likely to change the profession. An explanation can be found in their socio-economic situation and in the incompatibility of male expectations with career opportunities. In this context, direct working conditions don't seem to have a significant influence on teachers' attitude.