Teaching and learning in information retrieval

A literature review of pedagogical methods for teaching and learning information retrieval is presented. From the analysis of the literature a taxonomy was built and it is used to structure the paper. Information Retrieval (IR) is presented from different points of view: technical levels, educational goals, teaching and learning methods, assessment and curricula. The review is organized around two levels of abstraction which form a taxonomy that deals with the different aspects of pedagogy as applied to information retrieval. The first level looks at the technical level of delivering information retrieval concepts, and at the educational goals as articulated by the two main subject domains where IR is delivered: computer science (CS) and library and information science (LIS). The second level focuses on pedagogical issues, such as teaching and learning methods, delivery modes (classroom, online or e-learning), use of IR systems for teaching, assessment and feedback, and curricula design. The survey, and its bibliography, provides an overview of the pedagogical research carried out in the field of IR. It also provides a guide for educators on approaches that can be applied to improving the student learning experiences

Quantum description of the orientational degrees of freedom in a biaxial nematic liquid

The quantum mechanical version of a classical model for studying the orientational degrees of freedom corresponding to a nematic liquid composed of biaxial molecules is presented. The effective degrees of freedom are described by operators carrying an SU(3) representation, which allows the explicit calculation of the partition function in the mean field approximation. The algebraic consistency conditions are solved numerically and the equilibrium phases of the system are determined. In particular, the entropy, the specific heat and the order parameters are presented for different choices of the constituent biaxial molecules. Our results reproduce the classical calculation in the limit of high temperatures and high quantum numbers.Comment: 33 pages, Latex, 11 figure

From a discrete model of chemotaxis with volume-filling to a generalized Patlak–Keller–Segel model

We present a discrete model of chemotaxis whereby cells responding to a chemoattractant are seen as individual agents whose movement is described through a set of rules that result in a biased random walk. In order to take into account possible alterations in cellular motility observed at high cell densities (i.e. volume-filling), we let the probabilities of cell movement be modulated by a decaying function of the cell density. We formally show that a general form of the celebrated Patlak–Keller–Segel (PKS) model of chemotaxis can be formally derived as the appropriate continuum limit of this discrete model. The family of steady-state solutions of such a generalized PKS model are characterized and the conditions for the emergence of spatial patterns are studied via linear stability analysis. Moreover, we carry out a systematic quantitative comparison between numerical simulations of the discrete model and numerical solutions of the corresponding PKS model, both in one and in two spatial dimensions. The results obtained indicate that there is excellent quantitative agreement between the spatial patterns produced by the two models. Finally, we numerically show that the outcomes of the two models faithfully replicate those of the classical PKS model in a suitable asymptotic regime

Okapi-based XML indexing

Purpose – Being an important data exchange and information storage standard, XML has generated a great deal of interest and particular attention has been paid to the issue of XML indexing. Clear use cases for structured search in XML have been established. However, most of the research in the area is either based on relational database systems or specialized semi‐structured data management systems. This paper aims to propose a method for XML indexing based on the information retrieval (IR) system Okapi. Design/methodology/approach – First, the paper reviews the structure of inverted files and gives an overview of the issues of why this indexing mechanism cannot properly support XML retrieval, using the underlying data structures of Okapi as an example. Then the paper explores a revised method implemented on Okapi using path indexing structures. The paper evaluates these index structures through the metrics of indexing run time, path search run time and space costs using the INEX and Reuters RVC1 collections. Findings – Initial results on the INEX collections show that there is a substantial overhead in space costs for the method, but this increase does not affect run time adversely. Indexing results on differing sized Reuters RVC1 sub‐collections show that the increase in space costs with increasing the size of a collection is significant, but in terms of run time the increase is linear. Path search results show sub‐millisecond run times, demonstrating minimal overhead for XML search. Practical implications – Overall, the results show the method implemented to support XML search in a traditional IR system such as Okapi is viable. Originality/value – The paper provides useful information on a method for XML indexing based on the IR system Okapi

Symposium on Livestock Problems

Part 1 - John C. Macfarlane Livestock, animals raised in confinement, animals in large numbers shipped to other countries, and, of course, those cattle, calves, sheep, swine, goats, poultry and horses raised for the purpose of supplying meat for human and animal consumption will present problems that will increase in importance as long as they exist. Humane problems involving livestock are a hundred times more important and much more complex today than they were a hundred years ago. What can societies do to prevent or reduce this reservoir of potential cruelty? I think we can do many things. Part 2 - Dr. F.J. Mulhern I believe there is a growing awareness today by man of his total environment, and I\u27m speaking to you today as an administrator within government. Man, in looking at his environment, is searching to comprehend its parameters, and he feels very insecure until he really recognizes those parameters. In his search to find these parameters, he has become somewhat confused. However, I believe we are causing some changes in the area that I\u27m deeply associated with and I\u27d like to share some of them with you. I believe you can help us

Subduction Duration and Slab Dip

The dip angles of slabs are among the clearest characteristics of subduction zones, but the factors that control them remain obscure. Here, slab dip angles and subduction parameters, including subduction duration, the nature of the overriding plate, slab age, and convergence rate, are determined for 153 transects along subduction zones for the present day. We present a comprehensive tabulation of subduction duration based on isotopic ages of arc initiation and stratigraphic, structural, plate tectonic and seismic indicators of subduction initiation. We present two ages for subduction zones, a long‐term age and a reinitiation age. Using cross correlation and multivariate regression, we find that (1) subduction duration is the primary parameter controlling slab dips with slabs tending to have shallower dips at subduction zones that have been in existence longer; (2) the long‐term age of subduction duration better explains variation of shallow dip than reinitiation age; (3) overriding plate nature could influence shallow dip angle, where slabs below continents tend to have shallower dips; (4) slab age contributes to slab dip, with younger slabs having steeper shallow dips; and (5) the relations between slab dip and subduction parameters are depth dependent, where the ability of subduction duration and overriding plate nature to explain observed variation decreases with depth. The analysis emphasizes the importance of subduction history and the long‐term regional state of a subduction zone in determining slab dip and is consistent with mechanical models of subduction

Prostaglandin effects in the neuroendocrine mammalian brain

Publishers' versionThe original publication is available at http://www.samj.org.zaVarious prostaglandins (PGs) have been found in several areas of the brain. PGs of the E series have been found in the pituitary and pineal glands and the median eminence, and they have been shown to influence hypothalamic endocrine-release characteristics and release of melatonin from the pineal gland. It has been suggested that they may act, along with membrane phospholipids, as a link between neuronal depolarization, calcium uptake and neurotransmitter release. They may also influence postsynaptic effects of neurotransmitters. These latter effects may be due to interaction with membrane phospholipid- and cyclic nucleotide-induced changes of specific protein kinases. The PGs may act as intracellular mediators of neuro-endocrine control.Publishers' versio

Parallel computing for passage retrieval

In this paper we examine methods for both speeding up passage processing and examining more passages using parallel computers. We vary the number of passages processed in order to examine the effect on retrieval effectiveness and efficiency. The particular algorithm we apply has previously been used to good effect in Okapi experiments at TREC. We describe this algorithm and our mechanism for applying parallel computing to speed up the processing

What works for whom in pharmacist-led smoking cessation support: realist review

BACKGROUND: New models of primary care are needed to address funding and staffing pressures. We addressed the research question "what works for whom in what circumstances in relation to the role of community pharmacies in providing lifestyle interventions to support smoking cessation?" METHODS: This is a realist review conducted according to RAMESES standards. We began with a sample of 103 papers included in a quantitative review of community pharmacy intervention trials identified through systematic searching of seven databases. We supplemented this with additional papers: studies that had been excluded from the quantitative review but which provided rigorous and relevant additional data for realist theorising; citation chaining (pursuing reference lists and Google Scholar forward tracking of key papers); the 'search similar citations' function on PubMed. After mapping what research questions had been addressed by these studies and how, we undertook a realist analysis to identify and refine candidate theories about context-mechanism-outcome configurations. RESULTS: Our final sample consisted of 66 papers describing 74 studies (12 systematic reviews, 6 narrative reviews, 18 RCTs, 1 process detail of a RCT, 1 cost-effectiveness study, 12 evaluations of training, 10 surveys, 8 qualitative studies, 2 case studies, 2 business models, 1 development of complex intervention). Most studies had been undertaken in the field of pharmacy practice (pharmacists studying what pharmacists do) and demonstrated the success of pharmacist training in improving confidence, knowledge and (in many but not all studies) patient outcomes. Whilst a few empirical studies had applied psychological theories to account for behaviour change in pharmacists or people attempting to quit, we found no studies that had either developed or tested specific theoretical models to explore how pharmacists' behaviour may be affected by organisational context. Because of the nature of the empirical data, only a provisional realist analysis was possible, consisting of five mechanisms (pharmacist identity, pharmacist capability, pharmacist motivation and clinician confidence and public trust). We offer hypotheses about how these mechanisms might play out differently in different contexts to account for the success, failure or partial success of pharmacy-based smoking cessation efforts. CONCLUSION: Smoking cessation support from community pharmacists and their staff has been extensively studied, but few policy-relevant conclusions are possible. We recommend that further research should avoid duplicating existing literature on individual behaviour change; seek to study the organisational and system context and how this may shape, enable and constrain pharmacists' extended role; and develop and test theory

Are hygiene standards useful in assessing infection risk?

We monitored the surface level cleanliness of a five-bedded surgical intensive care unit (SICU) over a ten-week period in order to evaluate proposed hygiene standards.Ten environmental sites within SICU were sampled twice weekly along with collection of clinical and patient activity data. The standards designate aerobic colony counts (ACCs) >2.5cfu/cm2 from hand-touch sites and the presence of Staphylococcus aureus as hygiene failures. Nearly a quarter of 200 samples failed the standards, mostly from hand-touch sites on curtains, beds and medical equipment. The total number of fails each week was associated with bed occupancy (p=0.04), trending towards association with SICU-acquired infections (p=0.11). Environmental S.aureus was associated with the proportion of beds occupied (p = 0.02). Indistinguishable genotypes were found between patient and environmental staphylococci, with timescales supporting staphylococcal transmission in both directions. Hygiene standards based on microbial growth levels and the presence of S.aureus reflect patient activity and provide a means to risk manage infection. They also exposed a staphylococcal reservoir that could represent a more tangible risk to patients. Standards for surface level cleanliness deserve further evaluation