A Current Mode Detector Array for Gamma-Ray Asymmetry Measurements

We have built a CsI(Tl) gamma-ray detector array for the NPDGamma experiment to search for a small parity-violating directional asymmetry in the angular distribution of 2.2 MeV gamma-rays from the capture of polarized cold neutrons by protons with a sensitivity of several ppb. The weak pion-nucleon coupling constant can be determined from this asymmetry. The small size of the asymmetry requires a high cold neutron flux, control of systematic errors at the ppb level, and the use of current mode gamma-ray detection with vacuum photo diodes and low-noise solid-state preamplifiers. The average detector photoelectron yield was determined to be 1300 photoelectrons per MeV. The RMS width seen in the measurement is therefore dominated by the fluctuations in the number of gamma rays absorbed in the detector (counting statistics) rather than the intrinsic detector noise. The detectors were tested for noise performance, sensitivity to magnetic fields, pedestal stability and cosmic background. False asymmetries due to gain changes and electronic pickup in the detector system were measured to be consistent with zero to an accuracy of $10^{-9}$ in a few hours. We report on the design, operating criteria, and the results of measurements performed to test the detector array.Comment: 33 pages, 20 figures, 2 table

Reaching across continents : engaging students through virtual collaborations

Business schools have the responsibility of preparing students for work in multicultural organizations and global markets. This paper examines a situated learning experience for undergraduates through a virtual collaboration between a UK university and a Brazilian university. This facilitated remote communication using social media and smart devices, allowing students from both institutions to enhance their cross-cultural management competencies. A qualitative approach was used for the research, drawing on the reflections of the tutors from both institutions, and feedback received from students in the UK and Brazil. This paper provides empirical observations regarding the use of this innovative pedagogic approach, generating discussion of the implications for teaching, thus contributing to the literature on international collaborations in cross-cultural management education

MCT1-mediated transport of a toxic molecule is an effective strategy for targeting glycolytic tumors

There is increasing evidence that oncogenic transformation modifies the metabolic program of cells. A common alteration is the upregulation of glycolysis, and efforts to target glycolytic enzymes for anticancer therapy are under way. Here, we performed a genome-wide haploid genetic screen to identify resistance mechanisms to 3-bromopyruvate (3-BrPA), a drug candidate that inhibits glycolysis in a poorly understood fashion. We identified the SLC16A1 gene product, MCT1, as the main determinant of 3-BrPA sensitivity. MCT1 is necessary and sufficient for 3-BrPA uptake by cancer cells. Additionally, SLC16A1 mRNA levels are the best predictor of 3-BrPA sensitivity and are most elevated in glycolytic cancer cells. Furthermore, forced MCT1 expression in 3-BrPA–resistant cancer cells sensitizes tumor xenografts to 3-BrPA treatment in vivo. Our results identify a potential biomarker for 3-BrPA sensitivity and provide proof of concept that the selectivity of cancer-expressed transporters can be exploited for delivering toxic molecules to tumors.National Institutes of Health (U.S.) (NIH CA103866)Jane Coffin Childs Memorial Fund for Medical Research (Fellowship)National Science Foundation (U.S.) (Fellowship)Howard Hughes Medical Institute (Investigator

Measurement of the Parity Violating Asymmetry A

The weak pion-nucleon coupling constant H{sub {pi}}{sup 1} remains poorly determined, despite many years of effort. The recent measurement of the {sup 133}Cs anapole moment has been interpreted to give a value of H{sub {pi}}{sup 1} almost an order of magnitude larger than the limit established in the {sup 18}F parity doublet experiments. A measurement of the gamma ray directional asymmetry A{sub {gamma}} for the capture of polarized neutrons by hydrogen has been proposed at Los Alamos National Laboratory. This experiment will determine H{sub {pi}}{sup 1} independent of nuclear structure effects. However, since the predicted asymmetry is small, A{sub {gamma}} {approximately} 5 x 10{sup {minus}8}, systematic effects must be reduced to < 5 x 10{sup {minus}9}. The design of the experiment will is presented, with an emphasis on the techniques used for controlling systematic errors

Joint doctoral supervision across countries: changes, challenges and considerations.

Many universities international activities have increased enormously in volume, scope, and complexity in recent years (Altbach & Knight, 2007; Altbach, 2015) with education providers seeking more innovative ways to provide education across boundaries. Joint doctoral degrees are one example of such an initiative, focusing on international collaboration between institutions. Joint doctorates can provide richer and more rewarding learning experiences for PhD students, supervisors and colla- borating institutions. However, all the parties involved also need to be aware of the potential challenges and considerations that underpin effec- tive outcomes, as well as the key differences between joint degree docto- rates and doctorates with more traditional approaches. It has been pointed out that the literature on joint degree programmes is ‘thin’ pro- viding limited information for institutional leaders (and other parties involved in their setting up and conduct) who may be contemplating joint degree initiatives (Michael & Balraj, 2003). This chapter draws on a unique case study of a joint doctoral programme that operates across continents and academic cultures to illustrate the challenges and consid- erations that should be borne in mind prior to entering into joint doctoral arrangements. Various ways in which the associated challenges may be overcome are also suggested in order to support effective outcomes for all the parties involved

Problem-based learning in hybrid, blended and online courses: Instructional and change management implications for supporting learner engagement

Problem-based learning (PBL) is an instructional format which emphasizes collaborative and contextual learning and hence has favored face-to-face course design. However, with the plentitude of online tools which technology offers nowadays, PBL courses can also be effectively offered to students who cannot physically be present at the campus. The change process from offline to hybrid, blended, or online PBL courses need to be carefully managed and the right combination of technology and learning activities selected from the ever increasing available set. Hybrid, blended, or online courses differ in the amount of integration between offline and online activities. A mixed-method design was used to elaborate on how the different (hybrid, blended, or online) PBL courses can be effectively build and taught to create learner engagement. Twelve people (change agent, instructor, and participants) were interviewed and 82 students filled out a course evaluation form. The data was used to describe how a hybrid, blended, or online course was created and how the instructor and students perceived it. Instructional and change management implications for implementation are presented. Instructional implications deal with the needs of the learner, the role of the instructor, and the importance of sound technology integration in the course. Change management implication highlights the need to foster intra-institutional collaboration