Deformations of Closed Strings and Topological Open Membranes

We study deformations of topological closed strings. A well-known example is the perturbation of a topological closed string by itself, where the associative OPE product is deformed, and which is governed by the WDVV equations. Our main interest will be closed strings that arise as the boundary theory for topological open membranes, where the boundary string is deformed by the bulk membrane operators. The main example is the topological open membrane theory with a nonzero 3-form field in the bulk. In this case the Lie bracket of the current algebra is deformed, leading in general to a correction of the Jacobi identity. We identify these deformations in terms of deformation theory. To this end we describe the deformation of the algebraic structure of the closed string, given by the BRST operator, the associative product and the Lie bracket. Quite remarkably, we find that there are three classes of deformations for the closed string, two of which are exemplified by the WDVV theory and the topological open membrane. The third class remains largely mysterious, as we have no explicit example.Comment: 50 pages, LaTeX; V2: minor changes, 2 references added, V3: typos corrected, signs added, modified discussion on higher correlator

Japan, The Ambiguous, and My Shelf

Graduate Winner: 2nd Place, 2005. 18th Annual Carl Neureuther Student Book Collection Competition

Extracorporeal bullet trajectory determination from scanned phantoms with bullet defects

Shots with two different calibres (0.32 Auto and 9 mm Luger) were fired through phantoms that simulated human torsos, mounted on undercarriages with witness panels. The perforated phantoms were scanned with computed tomography (Siemens) using 80 kV and 140 kV and a slice thickness of 1 mm. The intracorporeal trajectories in the phantoms were compared to the known extracorporeal trajectories, derived from the perforations in witness panels. The discrepancy between the intracorporeal and extracorporeal trajectories, denoted as the absolute angle, was calculated for the trajectories before (front) and after (rear) the phantoms. Mean absolute angles at the front were lower than at the rear (2.27° vs. 4.54°) and the difference was statistically significant (p < 0.001). The results of the study imply that the line between the entrance and the exit wound in a scanned victim can be extended to the extracorporeal bullet trajectory leading towards the entrance wound. The absolute angles presented in this study give an impression of the expected errors with the two calibres. This can be helpful in shooting investigations to assess the position of the shooter from entrance and exit wounds in a scanned victim

Perceived effects of competency-based training on the acquisition of professional skills

The need to develop key competencies to meet the changing demands of industry has made the introduction of competency-based training (CBT) reforms in the Vocational Education and Training (VET) system a priority in many countries. This article explores the views of polytechnic students in Ghana on the effect of CBT on the acquisition of competencies to perform professional tasks. The results show that the modular structure has indirect effects on the acquisition of skills through quality teaching and feedback. It is argued that assessment in CBT needs to move away from emphasising more on routine tasks towards the development of broad sets of generic skills and adaptable workforce.</p

Does the group matter? Effects of trust, cultural diversity, and group formation on engagement in group work in higher education

Group work is a common active learning strategy in higher education when the goal is to enhance deep learning and develop teamwork skills. Culturally diverse learning groups are particularly valuable in preparing university students to participate in a globalized world. Student engagement in group work is critical in realizing these benefits. Therefore, more insight into what factors promote engagement is necessary. This study investigates the extent to which trust in the group, cultural diversity in the group, and group formation contribute to behavioral and cognitive engagement in group work. A questionnaire was filled out by 1025 bachelor’s students from six universities in the Netherlands and Canada. Structural equation modeling analyses identified students’ trust in the group as the strongest positive predictor of both behavioral and cognitive engagement. Greater perceived cultural diversity was found to promote behavioral and cognitive engagement, but compared with trust, the impacts were relatively small. Whether students could choose their group members did not affect behavioral or cognitive engagement significantly. Contrary to what was expected, trust did not act as a mediator. That is, cultural diversity and group formation did not indirectly affect engagement through trust. These findings prompt some suggestions for how to enhance student engagement in group work

Latest results from the PHOBOS experiment

Over the past years PHOBOS has continued to analyze the large datasets obtained from the first five runs of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The two main analysis streams have been pursued. The first one aims to obtain a broad and systematic survey of global properties of particle production in heavy ion collisions. The second class includes the study of fluctuations and correlations in particle production. Both type of studies have been performed for a variety of the collision systems, covering a wide range in collision energy and centrality. The uniquely large angular coverage of the PHOBOS detector and its ability to measure charged particles down to very low transverse momentum is exploited. The latest physics results from PHOBOS, as presented at Quark Matter 2008 Conference, are contained in this report.Comment: 9 pages, 9 figures, presented at the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur, India, Feb.4-10, 200

Role of therapeutic drug monitoring in pulmonary infections : use and potential for expanded use of dried blood spot samples

Respiratory tract infections are among the most common infections in men. We reviewed literature to document their pharmacological treatments, and the extent to which therapeutic drug monitoring (TDM) is needed during treatment. We subsequently examined potential use of dried blood spots as sample procedure for TDM. TDM was found to be an important component of clinical care for many (but not all) pulmonary infections. For gentamicin, linezolid, voriconazole and posaconazole dried blood spot methods and their use in TDM were already evident in literature. For glycopeptides, beta-lactam antibiotics and fluoroquinolones it was determined that development of a dried blood spot (DBS) method could be useful. This review identifies specific antibiotics for which development of DBS methods could support the optimization of treatment of pulmonary infections

Interculturally competent teachers:Behavioural dimensions and the role of study abroad

Intercultural Teaching Competence (ITC) is essential for teaching in increasingly diverse primary schools. However, research has not sufficiently addressed the meaning and development of ITC, including whether study abroad during teacher education contributes to the dimensions included. Therefore, this study seeks to determine which dimensions of ITC the respondent teachers report and whether there is a difference in ITC between teachers with or without study abroad experience. Survey data from 155 Dutch primary school teachers measure dimensions of ITC selected from prior literature, of which five can be measured reliably. Furthermore, compared with teachers without study abroad experience, teachers with such experience score significantly higher on the ITC dimensions of openness and storytelling

Kenyan doctoral students’ success: Roles of motivation and self-efficacy

Doctor of philosophy (PhD) degree holders are highly regarded in Kenya, especially in academia, and the Kenyan economy needs them to undertake administrative, research and innovation roles in both academia and industry. However, attaining this qualification is arduous, and Kenyan PhD programmes are characterized by low enrolment numbers, long degree completion times and low graduation rates. In other countries, PhD students’ success has been linked to motivation and self-efficacy. This cross-sectional study explores the extents to which motivation and self-efficacy relate to PhD student success in Kenya and to which this relationship differs across background and program characteristics. Using multiple linear regression, the authors analyse data from an online questionnaire administered to 628 PhD students enrolled between 2010 and 2018. The findings indicate that extrinsic motivation does not predict PhD students’ pace. Intrinsic motivation positively predicts students’ pace in the Medical Sciences program cluster and for those aged 51 years or older. Self-efficacy negatively predicts students’ pace in the Medical Sciences program cluster