Women,adult education and literacy: A Caribbean perspective

The main function of agricultural extension is generally thought to be the transfer through nonformal educational means of practical knowledge to agriculture and the enhancement of rural development. Agricultural extension has received renewed attention in recent years from international development agencies and considerable discussion has ensued regarding the appropriate role for extension programmes. Much of the attention has been directed towards improving the functions of existing services. This article discusses the policy considerations of extension within the broader context of agricultural development goals and the overall direction of the country's development objectives and strategies. A framework is presented for analysing important characteristics of different extension development options. The issues raised are relevant to the larger concerns of adult education policy and the promotion of lifelong learning strategies within society. They include the relationship of sectoral goals and policies to broader national objectives, the audience the public sector should target, the role of the private sector, the structural arrangements best suited to meet certain objectives and the correct mixture and co‐ordination of various services and programmes.     

Skipping class in college and exam performance: Evidence from a regression discontinuity classroom experiment

In this paper we estimate the effect of class attendance on exam performance by implementing a policy in three large economics classes that required students scoring below the median on the midterm exam to attend class. This policy generated a large discontinuity in the rate of post-midterm attendance at the median of the midterm score. We estimate that near the policy threshold, the post-midterm attendance rate was 36 percentage points higher for those students facing compulsory attendance. The discontinuous attendance policy is also associated with a significant difference in performance on the final exam. We estimate that a 10 percentage point increase in a student's overall attendance rate results in a 0.17 standard deviation increase in the final exam score without adversely affecting performance on other classes taken concurrently.     

A pipelined architecture for distributed text query evaluation

Two principal query-evaluation methodologies have been described for cluster-based implementation of distributed information retrieval systems: document partitioning and term partitioning. In a document-partitioned system, each of the processors hosts a subset of the documents in the collection, and executes every query against its local sub-collection. In a term-partitioned system, each of the processors hosts a subset of the inverted lists that make up the index of the collection, and serves them to a central machine as they are required for query evaluation. In this paper we introduce a pipelined query-evaluation methodology, based on a term-partitioned index, in which partially evaluated queries are passed amongst the set of processors that host the query terms. This arrangement retains the disk read benefits of term partitioning, but more effectively shares the computational load. We compare the three methodologies experimentally, and show that term distribution is inefficient and scales poorly. The new pipelined approach offers efficient memory utilization and efficient use of disk accesses, but suffers from problems with load balancing between nodes. Until these problems are resolved, document partitioning remains the preferred method. Alistair Moffat was supported by the Australian Research Council, the ARC Special Research Center for Perceptive and Intelligent Machines in Complex Environments, and the NICTA Victoria Laboratory. William Webber and Justin Zobel were supported by the Australian Research Council. Ricardo Baeza-Yates was supported by Grant P01-029-F from Millennium Initiative of Mideplan, Chile; and by the University of Melbourne as a visiting scholar at the time this project was undertaken.     

Hybrid capillary-inserted microfluidic device for sheathless particle focusing and separation in viscoelastic flow

A novel microfluidic device which consists of two stages for particle focusing and separation using a viscoelastic fluid has been developed. A circular capillary tube was used for three-dimensional particle pre-alignment before the separation process, which was inserted in a polydimethylsiloxane microchannel. Particles with diameters of 5 and 10 μm were focused at the centerline in the capillary tube, and the location of particles was initialized at the first bifurcation. Then, 5 and 10 μm particles were successfully separated in the expansion region based on size-dependent lateral migration, with ∼99% separation efficiency. The proposed device was further applied to separation of MCF-7 cells from leukocytes. Based on the cell size distribution, an approximate size cutoff for separation was determined to be 16 μm. At 200 μl/min, 94% of MCF-7 cells were separated with the purity of ∼97%. According to the trypan blue exclusion assay, high viability (∼90%) could be achieved for the separated MCF-7 cells. The use of a commercially available capillary tube enables the device to be highly versatile in dealing with particles in a wide size range by using capillary tubes with different inner diameters.     

David F. Treagust: congenial soul, science educator, and international research leader

For almost a half century David F. Treagust has been an exemplary science educator who has contributed through his dedication and commitments to students, curriculum development and collaboration with teachers, and cutting edge research in science education that has impacted the field globally, nationally and locally. A hallmark of his outstanding career is his collaborative style that inspires others to produce their best work.     

Perceptions of Retirement Affect Career Commitment: The Mediating Role of Retirement System Satisfaction for Two Teacher Age Groups

This study investigated a sample of California elementary, intermediate, and high school employed teachers (N = 247) to assess the effects of retirement perceptions on career commitment among teachers who are in different age groupings. Using path analysis, the influence of five retirement perceptions variables was examined: concerns about retirement benefits, understanding of the retirement system, perceived need for system change, control over the retirement plan, and satisfaction with current salary. The results indicated that the pattern of results differed for younger and older teachers. For the younger (age 21–45) group, concerns about retirement benefits (such as losing or reducing benefits through geographic mobility) and control over the retirement plan had significant, large, and direct effects on career commitment. For the older (age 46+) group, retirement variables had a significant effect on career commitment via the mediator of satisfaction with the retirement system. Given these findings, for younger teachers, strategies might focus on providing greater control over the retirement plan, such as in offering choice in how their retirement monies are invested. Older teachers need to feel safe about retirement in the sense of being satisfied with the system and its benefits to commit to their jobs.     

Anxiety and the Use of Alcohol‐Related Protective Behavioral Strategies

Protective behavioral strategies (PBS) are useful skills for reducing the negative consequences of alcohol. The moderating effects of anxiety on the relationship between 3 different types of PBS and negative consequences were examined among students accessing college counseling services. Results revealed a significant interaction between anxiety and strategies while drinking, suggesting that these simple strategies may be particularly beneficial among students who drink heavily and experience high levels of anxiety. Implications for counseling centers are discussed.