Automorphisms of abelian group extensions

Let $1 \to N \to G \to H \to 1$ be an abelian extension. The purpose of this paper is to study the problem of extending automorphisms of $N$ and lifting automorphisms of $H$ to certain automorphisms of $G$.Comment: 11 page

Analysis of regulatory network involved in mechanical induction of embryonic stem cell differentiation

Embryonic stem cells are conventionally differentiated by modulating specific growth factors in the cell culture media. Recently the effect of cellular mechanical microenvironment in inducing phenotype specific differentiation has attracted considerable attention. We have shown the possibility of inducing endoderm differentiation by culturing the stem cells on fibrin substrates of specific stiffness [1]. Here, we analyze the regulatory network involved in such mechanically induced endoderm differentiation under two different experimental configurations of 2-dimensional and 3-dimensional culture, respectively. Mouse embryonic stem cells are differentiated on an array of substrates of varying mechanical properties and analyzed for relevant endoderm markers. The experimental data set is further analyzed for identification of co-regulated transcription factors across different substrate conditions using the technique of bi-clustering. Overlapped bi-clusters are identified following an optimization formulation, which is solved using an evolutionary algorithm. While typically such analysis is performed at the mean value of expression data across experimental repeats, the variability of stem cell systems reduces the confidence on such analysis of mean data. Bootstrapping technique is thus integrated with the bi-clustering algorithm to determine sets of robust bi-clusters, which is found to differ significantly from corresponding bi-clusters at the mean data value. Analysis of robust bi-clusters reveals an overall similar network interaction as has been reported for chemically induced endoderm or endodermal organs but with differences in patterning between 2-dimensional and 3-dimensional culture. Such analysis sheds light on the pathway of stem cell differentiation indicating the prospect of the two culture configurations for further maturation. © 2012 Zhang et al

Negative Pressure and Naked Singularities in Spherical Gravitational Collapse

Assuming the weak energy condition, we study the nature of the non-central shell-focussing singularity which can form in the gravitational collapse of a spherical compact object in classical general relativity. We show that if the radial pressure is positive, the singularity is covered by a horizon. For negative radial pressures, the singularity will be covered if the ratio of pressure to the density is greater than -1/3 and naked if this ratio is $\leq -1/3$.Comment: 7 pages, LaTeX Fil

Bioremediation in prawn grow out systems - Winter school on recent advances in diagnosis and management of diseases in mariculture, 7th to 27th November 2002, Course Manual

In any aquaculture systems there exist a continuous exchange of substances between the bottom sediment and the overlying water, and between the two and the reared animal body. This exchange is strongly influenced by the inputs made continuously in to the system. As a matter of fact the bottom soil conditions and water quality in ponds are very much closely interrelated. Obviously, the water quality in ponds is very much influenced by the nutrient inputs, organic matter content, primary productivity and dissolved oxygen. Any aquaculture system has a finite capacity to assimilate nutrients, organic matter and the byproducts of degradation to a level congenial for the animals to grow. Bioremediation aims at the maintenance and enhancement of this finite capacity of the pond in favour and well being of the stock. Bioremediation in principle use microorganisms to transform/ decontaminate toxic pollutants in the environment. The process has two basic methods I. Bioaugmentation. 2. Biostimulation. One of the main concerns of bioremediation is that the degradation products, whatever it may be, should be non toxic to the stocked animals. Major advantages of bioremediation are I. It can be done on site (in-situ) 2. The process does not lead to any site disruption, 3. There is every possibility for permanent waste elimination, 4. Being a biological process it will be comparatively too inexpensive and 5. Can be effectively coupled with other treatment technologie

A case study: Promoting interprofessional community-based learning opportunities for health sciences students at the University of KwaZulu-Natal, Durban, South Africa

Background. Preventing disease and promoting health call for interprofessional collaboration of health professionals working in a team, making it important for student health professionals to experience collaborative teamwork while in training, rather than learning and working in silos. Objectives. To describe the opinions of participating students and supervising staff in an intraprofessional community-based initiative involving the disciplines of physiotherapy and dentistry at the University of KwaZulu-Natal (UKZN), Durban, South Africa. Methods. This was a qualitative descriptive study demonstrating teamwork of students from two health sciences disciplines, giving a joint health education talk to patients at a local community health centre. Data were collected from focus group discussions. Three such discussions were held with purposively selected samples: (i) 5 physiotherapy students; (ii) 6 dental therapy students; and (iii) 6 staff members from both disciplines who supervised the students. These data were analysed using thematic analysis. Ethical approval was obtained from UKZN. Results. By working collaboratively, the students believed that they learnt more about the other health professionals and obtained a deeper understanding of their roles within the healthcare team. Staff believed that the collaborative project could break down professional barriers to work cohesively in the work environment. The main difficulties encountered were the language barrier and rigid timetables. Conclusion. This case study provides an example of intraprofessional collaboration and teamwork, capable of positively influencing participating students, emphasising the need for interprofessional learning opportunities for students across all health sciences disciplines while in training

Assessment consolidates undergraduate students’ learning of community-based education

Background. Community-based education (CBE) is an empirical education experience that shifts clinical education from traditional to community settings to provide health sciences students with meaningful learning opportunities. However, assessing the effectiveness of these learning opportunities is a challenge.Objectives. To describe the methods used for assessment of CBE by the various disciplines in the School of Health Sciences, University of KwaZulu-Natal (UKZN), Durban, South Africa, and to determine how they were aligned to the anticipated learning outcomes. Methods. This qualitative study consisted of a purposively selected sample of 9 academics who participated in audio-taped interviews and focus group discussions, with the data being thematically analysed. Ethical approval was obtained from UKZN.Results. The disciplines in the School of Health Sciences used various assessment methods, ranging from simple tests, assignments and case presentations to more complex clinical assessments, blogging and portfolio assessments. Multiple methods were required to meet the anticipated learning outcomes of CBE, as a single assessment would not achieve this.Conclusion. The study findings indicated that assessment plays an important role in consolidating student learning at CBE sites, with multiple assessment methods being required to achieve graduate competencies in preparation for the workplace. Choice of assessment methods must be contextual and fit for purpose to allow for overall student development