Improving student retention and achievement: what do we know and what do we need to find out?

Why do some students in post-compulsory education abandon courses? And why do others not achieve their full potential? What can colleges do to improve student retention and achievement? This report reviews the research done to date. Research about retention and achievement is examined under headings such as student motivation and decision-making, demographic factors, college-related issues, and advice and guidance. The review refers to previously inaccessible research, including unpublished reports from conferences and internal reports from institutions. In conclusion, priorities for future research and its application are identified

Collective narratives and politics in the contemporary study of work : the new management practices debate

In this article we explore the question of how as sociologists of work we might research those who constitute the substance of our labour process. We approach this question through an examination of the New Management Practices debate, principally in the labour movement where a distinctive and critical view of NMP developed in the late 1980s. Second, we argue that there is a link between this debate and the wider politics of labour process discussion both within and beyond the labour movement which has witnessed a shift away from an earlier engagement with worker interventions. In response we suggest the need to re-evaluate the nature of academic engagement with labour thus reanimating a closer engagement with labour-in-work and collective worker narratives

Geothermal systems simulation: A case study

Geothermal reservoir simulation is a key step for developing sustainable and efficient strategies for the exploitation of geothermal resources. It is applied in the assessment of several areas of reservoir engineering, such as reservoir performance and re-injection programs, pressure decline in depletion, phase transition conditions, and natural evolution of hydrothermal convection systems. Fluid flow and heat transfer in rock masses, fluid-rock chemical interaction and rock mass deformation are some of the processes addressed in reservoir modelling. The case study of the Las Tres Virgenes (LTV) geothermal field (10 MWe), Baja California Sur, Mexico is presented. Three dimensional (3D) natural state simulations were carried out from emplacement and cooling of two spherical magma chambers using a conductive approach. A conceptual model of the volcanic system was developed on a lithostratigraphic and geochronological basis. Magma chamber volumes were established from eruptive volumes estimations. The thermophysical properties of the medium were assumed to correspond to the dominant rock in each lithological unit as an initial value, and further calibration was made considering histograms of experimentally obtained thermophysical properties of rocks. As the boundaries of the model lie far from the thermal anomaly, we assumed specified temperature boundaries. A Finite Volume (FV) numerical scheme was implemented in a Fortran 90 code to solve the heat equation. Static formation temperatures from well logs were used for validation of the numerical results. Good agreement was observed in those geothermal wells dominated by conductive heat transfer. For other wells, however, it is clear that conduction alone cannot explain observed behaviour, three-dimensional convective models are being implemented for future multiphysics simulations

State and Origin Branding in Hispanic Food Markets

Evaluations on the effectiveness of state and origin branding programs remain relatively scant and generally have not focused on specific target populations, including Hispanic consumers, the fastest-growing group. This study evaluates the effectiveness of the Arizona Grown brand and the nascent Mexico Selected Quality brand in differentiating and promoting food products in Hispanic markets. It was found that Hispanic consumers tend to view these food-product brands as nearly identical in perceived quality. Furthermore, they are willing to pay nearly equal premiums for products branded as such. These consumers saw no value in country-of-origin information alone.Agribusiness,

Radio numbers for generalized prism graphs

A radio labeling is an assignment $c:V(G) \rightarrow \textbf{N}$ such that every distinct pair of vertices $u,v$ satisfies the inequality d(u,v)+|c(u)-c(v)|\geq \diam(G)+1. The span of a radio labeling is the maximum value. The radio number of $G$, $rn(G)$, is the minimum span over all radio labelings of $G$. Generalized prism graphs, denoted $Z_{n,s}$, $s \geq 1$, $n\geq s$, have vertex set $\{(i,j)\,|\, i=1,2 \text{and} j=1,...,n\}$ and edge set $\{((i,j),(i,j \pm 1))\} \cup \{((1,i),(2,i+\sigma))\,|\,\sigma=-\left\lfloor\frac{s-1}{2}\right\rfloor\,\ldots,0,\ldots,\left\lfloor\frac{s}{2}\right\rfloor\}$. In this paper we determine the radio number of $Z_{n,s}$ for $s=1,2$ and $3$. In the process we develop techniques that are likely to be of use in determining radio numbers of other families of graphs.Comment: To appear in Discussiones Mathematicae Graph Theory. 16 pages, 1 figur

Giving order to image queries

Users of image retrieval systems often find it frustrating that the image they are looking for is not ranked near the top of the results they are presented. This paper presents a computational approach for ranking keyworded images in order of relevance to a given keyword. Our approach uses machine learning to attempt to learn what visual features within an image are most related to the keywords, and then provide ranking based on similarity to a visual aggregate. To evaluate the technique, a Web 2.0 application has been developed to obtain a corpus of user-generated ranking information for a given image collection that can be used to evaluate the performance of the ranking algorithm