Finite size effects on MπM_\pi in QCD from Chiral Perturbation Theory

We present a determination of the shift $M_\pi(L)-M_\pi$ due to the finite spatial box size $L$ by means of $N_f=2$ Chiral Perturbation Theory and L\"uscher's formula. The range of applicability of the chiral prediction is discussed.Comment: 3 pages, 3 figures, Lattice2002(spectrum

The conceptualisation of "soft skills" among medical students before and after curriculum reform

Objective: This paper reports on the conceptualisation of "soft skills" as part of a study carried out among two groups of undergraduate medical students before and after curriculum reform at the School of Medicine of the University of Pretoria. Congruent with a call from the World Psychiatric Association, the curriculum reform that was undertaken aimed, inter alia, to place more emphasis on soft skills, including professional interpersonal and social skills, communication skills, and professional and ethical attitudes. Methods: Qualitative methods were used to arrive at a descriptive comparison of the conceptualisation of soft skills by final-year medical students of the traditional curriculum with those of final-year students who had followed the reformed curriculum. A purposive-theoretical sampling method was followed; 42 students from the traditional curriculum and 49 from the reformed curriculum were sampled. Data were collected from seven focus groups, 16 individual interviews, and 23 essays (autobiographical sketches). Results: Both groups of students revealed conceptualisations of soft skills that were similar in kind. The themes they pinpointed were the doctor-patient relationship; relationships with other professionals; being a good listener; explaining things to patients; using good communication skills; establishing rapport with patients from different cultural backgrounds; having a professionally correct attitude; being really interested in patients' well being; having empathy; coping with patients, managing difficult situations, and being ethical and professional. However, the traditional curriculum students offered fewer examples and described fewer experiences that exemplified their soft skills. Students following the reformed curriculum gave rich accounts of their conceptualisation in terms of their own experiences and practical examples of how soft skills had been or could be used, particularly in difficult interpersonal situations. Moreover, they came up with helpful ways of dealing with difficult situations, which surpassed the suggestions offered by the students following the traditional curriculum. Conclusion: The educational and training efforts of the reformed curriculum are associated with an adeptness on the part of the students at applying soft skills to the demands of difficult clinical situations. Keywords: soft skills, interpersonal skills, doctor-patient relationship, professional socialisation South African Psychiatry Review Vol. 9(1) 2006: 33-3

Medical students on the value of role models for developing 'soft skills' - "That's the way you do it

Objective: The Soft Skills Project examined the professional development of medical students at the University of Pretoria, especially their doctor-patient interaction skills and professional socialisation. This paper reports on one of the findings of the project, namely the importance that medical students attach to role models in the development of soft skills. Methods: We used a qualitative method with symbolic interactionism and grounded theory as framework. Fourty two final-year students from the last cohort following the traditional curriculum at the University of Pretoria in 2001, and 49 final years from the first cohort following the reformed curriculum in 2002 were recruited. Data were collected by applying focus groups, in-depth, individual interviews, as well as autobiographical sketches. Data were captured by means of audio tape recordings, transcripts of the tapes, researchers' field notes, and written accounts by students, and were analysed by using a general inductive approach. Results: There were no striking differences between the comments of the two groups. Students considered registrars to be the most influential role models in the clinical teaching context, followed by specialist consultants. Their idea of a good role model was a clinically and academically competent doctor that cared about patients, had good interpersonal skills, and who could inspire students. Students needed and appreciated good role models to help them to develop their own soft skills. They expected guidance and behavioural examples from clinical teachers. Although there were competent role models, the students were exposed to poor role models. Poor role models mainly affect students negatively. Students tend to imitate and perpetuate unacceptable behaviour. Furthermore, poor role models have a negative emotional effect on students and are detrimental to their moral and learning environment. Sometimes, poor role models have a paradoxical positive effect in the sense that they inform students how not to behave. Conclusion: Medical schools and medical doctors working with medical students should be consciously aware of the importance of role models both when allocating clinical teachers to students, and while performing duties with students. It is especially necessary to realise that poor role modelling has important detrimental effects on students. Therefore, an attempt should be made to ensure that not only clinical examination skills, but also soft skills, are demonstrated at the bedside. Measures to ensure adequate exposure of students to positive role models could include: staff development; the identification of good role models to guide registrars; and a reallocation of tasks, where possible, to increase the exposure of students to the ‘natural' role models. Keywords: soft skills, role models, medical students, professionalism South African Psychiatry Review Vol. 9(1) 2006: 28-3

Medical students' perceptions of their development of ‘soft skills' Part II : The development of ‘soft skills' through ‘guiding and growing'

BackgroundThis paper reports on medical students' views on the ways in which their ‘soft skills' were developed. It is the result of a study on soft skills among two groups of students before and after curriculum reform at the School of Medicine of the University of Pretoria. One of the aims of the reform was to provide more teaching and learning opportunities for the development of soft skills. Soft skills include professional interpersonal and social skills, communication skills, and professional and ethical attitudes.MethodsAs symbolic interactionism was used as the theoretical framework to guide the research, qualitative methods were used to collect the data. A purposive-theoretical sample of 42 final-year medical students from the traditional curriculum and 49 from the reformed curriculum was recruited. Data were collected by means of focus groups, individual in-depth interviews and autobiographical sketches. ResultsThe same categories of comments emerged from the data collected from the study participants from both the traditional and the reformed curriculum. The students ascribed their behaviour related to soft skills to personality and innate features. They had varying opinions on whether soft skills could be taught, but there was as a strong feeling that teaching should focus on principles and guidelines for dealing with difficult situations. They believed that, in the end, they should take responsibility for their own development of soft skills. Most participants felt they could at least grow through exposure to teaching activities and the observation of role models. They also indicated that they had developed their soft skills and constructed their own identity through their interaction with others. Their definition of situations was shaped by their interactions with doctors and educators, fellow students and other health professionals. Interaction with patients was considered the most important. For both groups of students their third year was a watershed, as it is the first year of more intensive patient contact and the beginning of serious learning from interaction with patients. The views on the development of soft skills differed very little between the traditional and reformed curriculum groups, except that students who had followed the reformed curriculum felt more prepared through the increased teaching and training efforts. Further consideration needs to be given to the intention of the changed curriculum compared to the actual effect. The way in which the participants in the study described their development of soft skills could be categorised as a complex interplay between ‘being' and ‘becoming'. Instead of using the word ‘acquisition' of soft skills, ‘development' seemed to be more appropriate. The metaphor of ‘guiding' and ‘growing' also captures the development of these skills better than the terms ‘teaching' and ‘learning'.ConclusionTeaching activities in the clinical years should be adapted with a view to facilitating the students' professional growth. New models for the development of medical educators should be created and institutional barriers should be investigated.For full text, click here: SA Fam Pract 2006;48(8):15-15

3D time series analysis of cell shape using Laplacian approaches

Background: Fundamental cellular processes such as cell movement, division or food uptake critically depend on cells being able to change shape. Fast acquisition of three-dimensional image time series has now become possible, but we lack efficient tools for analysing shape deformations in order to understand the real three-dimensional nature of shape changes. Results: We present a framework for 3D+time cell shape analysis. The main contribution is three-fold: First, we develop a fast, automatic random walker method for cell segmentation. Second, a novel topology fixing method is proposed to fix segmented binary volumes without spherical topology. Third, we show that algorithms used for each individual step of the analysis pipeline (cell segmentation, topology fixing, spherical parameterization, and shape representation) are closely related to the Laplacian operator. The framework is applied to the shape analysis of neutrophil cells. Conclusions: The method we propose for cell segmentation is faster than the traditional random walker method or the level set method, and performs better on 3D time-series of neutrophil cells, which are comparatively noisy as stacks have to be acquired fast enough to account for cell motion. Our method for topology fixing outperforms the tools provided by SPHARM-MAT and SPHARM-PDM in terms of their successful fixing rates. The different tasks in the presented pipeline for 3D+time shape analysis of cells can be solved using Laplacian approaches, opening the possibility of eventually combining individual steps in order to speed up computations

Evidence for a fractional quantum Hall state with anisotropic longitudinal transport

At high magnetic fields, where the Fermi level lies in the N=0 lowest Landau level (LL), a clean two-dimensional electron system (2DES) exhibits numerous incompressible liquid phases which display the fractional quantized Hall effect (FQHE) (Das Sarma and Pinczuk, 1997). These liquid phases do not break rotational symmetry, exhibiting resistivities which are isotropic in the plane. In contrast, at lower fields, when the Fermi level lies in the $N\ge2$ third and several higher LLs, the 2DES displays a distinctly different class of collective states. In particular, near half filling of these high LLs the 2DES exhibits a strongly anisotropic longitudinal resistance at low temperatures (Lilly et al., 1999; Du et al., 1999). These "stripe" phases, which do not exhibit the quantized Hall effect, resemble nematic liquid crystals, possessing broken rotational symmetry and orientational order (Koulakov et al., 1996; Fogler et al., 1996; Moessner and Chalker, 1996; Fradkin and Kivelson, 1999; Fradkin et al, 2010). Here we report a surprising new observation: An electronic configuration in the N=1 second LL whose resistivity tensor simultaneously displays a robust fractionally quantized Hall plateau and a strongly anisotropic longitudinal resistance resembling that of the stripe phases.Comment: Nature Physics, (2011

Multiplexed, High Density Electrophysiology with Nanofabricated Neural Probes

Extracellular electrode arrays can reveal the neuronal network correlates of behavior with single-cell, single-spike, and sub-millisecond resolution. However, implantable electrodes are inherently invasive, and efforts to scale up the number and density of recording sites must compromise on device size in order to connect the electrodes. Here, we report on silicon-based neural probes employing nanofabricated, high-density electrical leads. Furthermore, we address the challenge of reading out multichannel data with an application-specific integrated circuit (ASIC) performing signal amplification, band-pass filtering, and multiplexing functions. We demonstrate high spatial resolution extracellular measurements with a fully integrated, low noise 64-channel system weighing just 330 mg. The on-chip multiplexers make possible recordings with substantially fewer external wires than the number of input channels. By combining nanofabricated probes with ASICs we have implemented a system for performing large-scale, high-density electrophysiology in small, freely behaving animals that is both minimally invasive and highly scalable

Chiral Effective Lagrangian and Quark Masses

The status of lattice determinations of quark masses is reviewed (with the exception of m_b). Attempts to extract the low-energy constants in the effective chiral Lagrangian are discussed, with special emphasis on those couplings which are required to test the hypothesis of a massless up-quark. Furthermore, the issue of quenched chiral logarithms is addressed.Comment: Invited talk presented at Lattice2002(plenary), 12 pages, 3 figure

Longitudinal grey and white matter changes in frontotemporal dementia and Alzheimer's disease

Behavioural variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD) dementia are characterised by progressive brain atrophy. Longitudinal MRI volumetry may help to characterise ongoing structural degeneration and support the differential diagnosis of dementia subtypes. Automated, observer-independent atlas-based MRI volumetry was applied to analyse 102 MRI data sets from 15 bvFTD, 14 AD, and 10 healthy elderly control participants with consecutive scans over at least 12 months. Anatomically defined targets were chosen a priori as brain structures of interest. Groups were compared regarding volumes at clinic presentation and annual change rates. Baseline volumes, especially of grey matter compartments, were significantly reduced in bvFTD and AD patients. Grey matter volumes of the caudate and the gyrus rectus were significantly smaller in bvFTD than AD. The bvFTD group could be separated from AD on the basis of caudate volume with high accuracy (79% cases correct). Annual volume decline was markedly larger in bvFTD and AD than controls, predominantly in white matter of temporal structures. Decline in grey matter volume of the lateral orbitofrontal gyrus separated bvFTD from AD and controls. Automated longitudinal MRI volumetry discriminates bvFTD from AD. In particular, greater reduction of orbitofrontal grey matter and temporal white matter structures after 12 months is indicative of bvFTD