Non-Fermi liquid behavior below the Néel temperature in the frustrated heavy fermion magnet UAu₂

The term Fermi liquid is almost synonymous with the metallic state. The association is known to break down at quantum critical points (QCPs), but these require precise values of tuning parameters, such as pressure and applied magnetic field, to exactly suppress a continuous phase transition temperature to the absolute zero. Three-dimensional non-Fermi liquid states, apart from superconductivity, that are unshackled from a QCP are much rarer and are not currently well understood. Here, we report that the triangular lattice system uranium diauride (UAu2) forms such a state with a non-Fermi liquid low-temperature heat capacity [Formula: see text] and electrical resistivity [Formula: see text] far below its Néel temperature. The magnetic order itself has a novel structure and is accompanied by weak charge modulation that is not simply due to magnetostriction. The charge modulation continues to grow in amplitude with decreasing temperature, suggesting that charge degrees of freedom play an important role in the non-Fermi liquid behavior. In contrast with QCPs, the heat capacity and resistivity we find are unusually resilient in magnetic field. Our results suggest that a combination of magnetic frustration and Kondo physics may result in the emergence of this novel state

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

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

Attosecond physics at the nanoscale

Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto- and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds, which is comparable with the optical field. On the other hand, the second branch involves the manipulation and engineering of mesoscopic systems, such as solids, metals and dielectrics, with nanometric precision. Although nano-engineering is a vast and well-established research field on its own, the merger with intense laser physics is relatively recent. In this article we present a comprehensive experimental and theoretical overview of physics that takes place when short and intense laser pulses interact with nanosystems, such as metallic and dielectric nanostructures. In particular we elucidate how the spatially inhomogeneous laser induced fields at a nanometer scale modify the laser-driven electron dynamics. Consequently, this has important impact on pivotal processes such as ATI and HHG. The deep understanding of the coupled dynamics between these spatially inhomogeneous fields and matter configures a promising way to new avenues of research and applications. Thanks to the maturity that attosecond physics has reached, together with the tremendous advance in material engineering and manipulation techniques, the age of atto-nano physics has begun, but it is in the initial stage. We present thus some of the open questions, challenges and prospects for experimental confirmation of theoretical predictions, as well as experiments aimed at characterizing the induced fields and the unique electron dynamics initiated by them with high temporal and spatial resolution

Scalable and privacy-respectful interactive discovery of place semantics from human mobility traces

Mobility diaries of a large number of people are needed for assessing transportation infrastructure and for spatial development planning. Acquisition of personal mobility diaries through population surveys is a costly and error-prone endeavour. We examine an alternative approach to obtaining similar information from episodic digital traces of people’s presence in various locations, which appear when people use their mobile devices for making phone calls, accessing the internet, or posting georeferenced contents (texts, photos, or videos) in social media. Having episodic traces of a person over a long time period, it is possible to detect significant (repeatedly visited) personal places and identify them as home, work, or place of social activities based on temporal patterns of a person’s presence in these places. Such analysis, however, can lead to compromising personal privacy. We have investigated the feasibility of deriving place meanings and reconstructing personal mobility diaries while preserving the privacy of individuals whose data are analysed. We have devised a visual analytics approach and a set of supporting tools making such privacy-preserving analysis possible. The approach was tested in two case studies with publicly available data: simulated tracks from the VAST Challenge 2014 and real traces built from georeferenced Twitter posts

Balancing Selection at the Tomato RCR3 Guardee Gene Family Maintains Variation in Strength of Pathogen Defense

Coevolution between hosts and pathogens is thought to occur between interacting molecules of both species. This results in the maintenance of genetic diversity at pathogen antigens (or so-called effectors) and host resistance genes such as the major histocompatibility complex (MHC) in mammals or resistance (R) genes in plants. In plant-pathogen interactions, the current paradigm posits that a specific defense response is activated upon recognition of pathogen effectors via interaction with their corresponding R proteins. According to the''Guard-Hypothesis,'' R proteins (the ``guards'') can sense modification of target molecules in the host (the ``guardees'') by pathogen effectors and subsequently trigger the defense response. Multiple studies have reported high genetic diversity at R genes maintained by balancing selection. In contrast, little is known about the evolutionary mechanisms shaping the guardee, which may be subject to contrasting evolutionary forces. Here we show that the evolution of the guardee RCR3 is characterized by gene duplication, frequent gene conversion, and balancing selection in the wild tomato species Solanum peruvianum. Investigating the functional characteristics of 54 natural variants through in vitro and in planta assays, we detected differences in recognition of the pathogen effector through interaction with the guardee, as well as substantial variation in the strength of the defense response. This variation is maintained by balancing selection at each copy of the RCR3 gene. Our analyses pinpoint three amino acid polymorphisms with key functional consequences for the coevolution between the guardee (RCR3) and its guard (Cf-2). We conclude that, in addition to coevolution at the ``guardee-effector'' interface for pathogen recognition, natural selection acts on the ``guard-guardee'' interface. Guardee evolution may be governed by a counterbalance between improved activation in the presence and prevention of auto-immune responses in the absence of the corresponding pathogen

Effect of tube diameter and capillary number on platelet margination and near-wall dynamics

The effect of tube diameter $D$ and capillary number $Ca$ on platelet margination in blood flow at $\approx 37\%$ tube haematocrit is investigated. The system is modelled as three-dimensional suspension of deformable red blood cells and nearly rigid platelets using a combination of the lattice-Boltzmann, immersed boundary and finite element methods. Results show that margination is facilitated by a non-diffusive radial platelet transport. This effect is important near the edge of the cell-free layer, but it is only observed for $Ca > 0.2$, when red blood cells are tank-treading rather than tumbling. It is also shown that platelet trapping in the cell-free layer is reversible for $Ca \leq 0.2$. Only for the smallest investigated tube ($D = 10 \mu\text{m}$) margination is essentially independent of $Ca$. Once platelets have reached the cell-free layer, they tend to slide rather than tumble. The tumbling rate is essentially independent of $Ca$ but increases with $D$. Tumbling is suppressed by the strong confinement due to the relatively small cell-free layer thickness at $\approx 37\%$ tube haematocrit.Comment: 16 pages, 10 figure

Precision Measurement of the Mass of the h_c(1P1) State of Charmonium

A precision measurement of the mass of the h_c(1P1) state of charmonium has been made using a sample of 24.5 million psi(2S) events produced in e+e- annihilation at CESR. The reaction used was psi(2S) -> pi0 h_c, pi0 -> gamma gamma, h_c -> gamma eta_c, and the reaction products were detected in the CLEO-c detector. Data have been analyzed both for the inclusive reaction and for the exclusive reactions in which eta_c decays are reconstructed in fifteen hadronic decay channels. Consistent results are obtained in the two analyses. The averaged results of the present measurements are M(h_c)=3525.28+-0.19 (stat)+-0.12(syst) MeV, and B(psi(2S) -> pi0 h_c)xB(h_c -> gamma eta_c)= (4.19+-0.32+-0.45)x10^-4. Using the 3PJ centroid mass, Delta M_hf(1P)= - M(h_c) = +0.02+-0.19+-0.13 MeV.Comment: 9 pages, available through http://www.lns.cornell.edu/public/CLNS/, submitted to PR

Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model

Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures