Searching for Cooling Signatures in Strong Lensing Galaxy Clusters: Evidence Against Baryons Shaping the Matter Distribution in Cluster Cores

The process by which the mass density profile of certain galaxy clusters becomes centrally concentrated enough to produce high strong lensing (SL) cross-sections is not well understood. It has been suggested that the baryonic condensation of the intra-cluster medium (ICM) due to cooling may drag dark matter to the cores and thus steepen the profile. In this work, we search for evidence of ongoing ICM cooling in the first large, well-defined sample of strong lensing selected galaxy clusters in the range 0.1 < z < 0.6. Based on known correlations between the ICM cooling rate and both optical emission line luminosity and star formation, we measure, for a sample of 89 strong lensing clusters, the fraction of clusters that have [OII]3727 emission in their brightest cluster galaxy (BCG). We find that the fraction of line-emitting BCGs is constant as a function of redshift for z > 0.2 and shows no statistically significant deviation from the total cluster population. Specific star formation rates, as traced by the strength of the 4000 angstrom break, D_4000, are also consistent with the general cluster population. Finally, we use optical imaging of the SL clusters to measure the angular separation, R_arc, between the arc and the center of mass of each lensing cluster in our sample and test for evidence of changing [OII] emission and D_4000 as a function of R_arc, a proxy observable for SL cross-sections. D_4000 is constant with all values of R_arc, and the [OII] emission fractions show no dependence on R_arc for R_arc > 10" and only very marginal evidence of increased weak [OII] emission for systems with R_arc < 10". These results argue against the ability of baryonic cooling associated with cool core activity in the cores of galaxy clusters to strongly modify the underlying dark matter potential, leading to an increase in strong lensing cross-sections.Comment: 9 Pages, 5 Figures, 1 Tabl

Divergence in seasonal hydrology across northern Eurasia: Emerging trends and water cycle linkages

Discharge from large Eurasia rivers increased during the 20th century, yet much remains unknown regarding details of this increasing freshwater flux. Here, for the three largest Eurasian basins (the Ob, Yenisei, and Lena) we examine the nature of annual and seasonal discharge trends by investigating the flow changes along with those for precipitation, snow depth, and snow water equivalent. On the basis of a multiperiod trend analysis and examination of station data, we propose two characteristic regimes to explain the long‐term discharge increase from these large Eurasian rivers. Over the early decades from approximately 1936 to 1965, annual precipitation correlates well with annual discharge, and positive discharge trends are concurrent with summer/fall discharge increases. The latter decades were marked by a divergence between winter/spring flows, which increased, amid summer/fall discharge declines. A comparison of cold season precipitation (CSP) and spring discharge trends across subbasins of the Ob, Yenisei, and Lena shows limited agreement with one precipitation data set but good agreement (R2 \u3e 0.90) when a second is used. While natural variability in the Arctic system tends to mask these emerging trends, spatial and temporal changes can generally be characterized by increased solid precipitation, primarily to the north, along with a drier hydrography during the warm season

An exploratory study to determine students' perceptions of the value of interaction in an Australian classroom context and the perceived impact on learning outcomes

Interaction has long been a defining and critical component of the educational process, whatever the classroom context (Anderson 2003). This paper presents findings of a study to explore the attitudes of students at an Australian university towards various types interactivity in the classroom. The study also investigates students perceptions of how interactivity in the classroom impacts on cognitive, affective and behavioural learning outcomes. In a recent review of the literature Muirhead & Juwah (2003) argue that interactivity is critical in underpinning the learning process in face-to-face, campus based and distance and online education. They say that interactions serve a diverse range of functions in the educational process, which include learner to learner, learner to content, learner to tutor, learner to technology, tutor to content, tutor to technology, content to content. These functions promote and enhance the quality of active, participative learning in a learning environment. However, literature indicates that attitudes towards active learning involving greater interactivity varies across students and between students and lecturers (Billings, Connors, & Skiba 2001). Investigation into student attitudes of the value and effectiveness of interaction is of particular interest for educators who are adapting the learning of a diverse range of students, including oncampus, distance, international, under and postgradute students. Much of the existing research into classroom interaction was grounded in the behaviourist and cognitive sciences approach to learning and teaching, where traditional classroom interaction placed the teacher at the centre of all activities as transmitter of knowledge and co-coordinator of student interaction (McLoughlin 2002). Those studies predate the recent application of constructivism (Bonk and Cunningham 1998) and social learning theory (Bandura (1977), and the emphasis on building life long learning skills. This research will contribute to current discussion about the role of interaction in learning, based on a constructivist approach to developing life long learning skills. This paper will present the findings of an exploratory study of students’ attitudes to various types of interaction in a classroom context. The first step of this exploratory study will employ a focus group approach to gather data from on campus students to identify the key issues that emerge from this data. These findings will be used to design a survey instrument to implement a follow-up research project

Putting severity of punishment back in the deterrence package

Studies of criminal deterrence usually show an effect of certainty of punishment but often fail to find an effect of severity. This is a serious threat to the theoretical underpinnings of deterrence theory. Through both a survey of 39 analyses in 33 published studies and our own reanalysis of an often-used data set, we show the problem rests not with the theory but with the analysis of the theory. Finding no severity effect can be traced to â unbundling the theoretical packageâ when moving from the theory to the statistical models used to represent the theory

Dynamics of left-right party positions : separating systematic movements from noise

We investigate whether it is feasible to use the Comparative Manifesto Project (CMP) data on party positioning to take account of party movements along the left-right dimension. At issue are answers to two questions. Are there discernable dynamics in party positions? And, if so, is it possible to separate systematic party dynamics from measurement error so as to make effective use of the CMP data? The answer to both questions is yes. Our analysis of 81 parties across the post-War period detects systematic movements in the left-right positions for one third of the parties. Our analysis of measurement error reveals that, as measured by the CMP, about 65% of the variance in party positions records reliable long-term differences across parties, another 16% records systematic movements, and the remaining 19% is error. We conclude with discussions of what one should make of this mix of stability, movements, and error and what one should do about it when using the CMP data to analyze substantively important questions about politics and policy. Of particular importance are our recommendation to be ever mindful of the two possible sources of error—a faulty instrument and erratic behavior on the part of parties themselves—and our suggestion for how to separate or combine those possibilities depending on one’s theoretical concern

Cross-temporal and cross-national comparisons of party left-right positions

We investigate the cross-time and cross-nation comparability of party left-right position measurements by expert surveys and the Comparative Manifesto Project (CMP). While expert surveys show party left-right positions to be mostly static, we find the CMP records systematic party movements for one-third of the parties analyzed. On the issue of cross-national comparability, we find cross-national variation in expert surveys is muted. They contain little more than the variation associated with reputations based on party-family affiliation. The CMP measurements, on the other hand, contain variation attributable to national party-system differences. We conclude with thoughts about why all of this is so and about how one might navigate the expert survey limitations depending on the question one wants to answer about democratic politics and policy making

What are elections for? conferring the median mandate

Democracy is often described as a system in which a majority of electors choose one out of a number of competing parties to form a government and carry out its programme. Unfortunately, spontaneous majorities rarely form in support of one party. We generalize from a 'government' to a 'median' mandate, in which the median elector chooses the pivotal party in parliament, which then translates his or her preferences into public policy. To check this we investigate how accurately parliaments and governments represent the left-right position of the median voter in each of twenty parliamentary democracies. Distortions depend on the type of electoral arrangement, being relatively smaller under proportional representation than under single-member districts. Distortions do not equate to biased representation, however. Once we consider how distortions at one step or one time are compensated by distortions in the opposite direction at another, overall representation of the median voter position is reasonably accurate

The Application of Teaching Quality indicators in Saudi Higher Education by the perspective of academics

This paper investigated the level of application of teaching quality indicators (TQIs) in Saudi higher education by the perspective of academics. Data were collected through an online survey of 467 academics in 21 Faculties of Education (SFEs). The online survey consisted of (20) items. Participants were asked to indicate the level of application of TQIs in SFEs. The study is important as it deals with the sensitive issue of teaching quality in higher education and its indicator, which is reflected upon in a positive way to enhance the teaching and learning quality in Saudi universities, and particular SFEs. Findings reveal the overall mean scores of the level of application of TQIs was an ‘Occasionally level’. The results also showed that there were statistically significant differences attribute to the age, level of education and years of teaching experience in higher education. Based on these findings, this paper provides recommendations to planning for achieving TQ in Saudi higher education, taking into consideration the perspectives of academics, their involvement in the processes of planning and improving TQ, and the policies and procedures developed to guide the application of TQIs in Saudi higher education, particular in SFEs. Keywords: teaching quality; indicators; planning, faculties of education; Saudi higher educatio

The changing face of the Portuguese parties : strategic innovation and the dimensionality of the party policy space

We provide a comprehensive analysis of the Portuguese parties and their policy space. We show how and how well the parties have been able to adapt to the changing environment in the party system. Our analyses show that, not only are we able check existing static expert assessments of the Portuguese party and policy space, but we are also able to track the dynamics of the system. In this way, we expand on what little has been said thus far about the Portuguese party system. We conclude with three important ideas. First, we confirm that the Portuguese policy space is unidimensional, with the parties lining up from Left to Right, as some but not all experts, have suggested. Second, we propose that the environment of the Portuguese party system is one of compression, that is, parties have been office-seekers in that they have all been approaching the Centre of the political spectrum for a number of reasons we explore in detail. Last, we learn that only through issue dimensions and how parties pronounce themselves on these dimensions are the smaller parties able to survive and avoid extinction in the compressing environment of the party system