Vortices in quantum droplets: Analogies between boson and fermion systems

The main theme of this review is the many-body physics of vortices in quantum droplets of bosons or fermions, in the limit of small particle numbers. Systems of interest include cold atoms in traps as well as electrons confined in quantum dots. When set to rotate, these in principle very different quantum systems show remarkable analogies. The topics reviewed include the structure of the finite rotating many-body state, universality of vortex formation and localization of vortices in both bosonic and fermionic systems, and the emergence of particle-vortex composites in the quantum Hall regime. An overview of the computational many-body techniques sets focus on the configuration interaction and density-functional methods. Studies of quantum droplets with one or several particle components, where vortices as well as coreless vortices may occur, are reviewed, and theoretical as well as experimental challenges are discussed.Comment: Review article, 53 pages, 53 figure

Variational Monte Carlo for Interacting Electrons in Quantum Dots

We use a variational Monte Carlo algorithm to solve the electronic structure of two-dimensional semiconductor quantum dots in external magnetic field. We present accurate many-body wave functions for the system in various magnetic field regimes. We show the importance of symmetry, and demonstrate how it can be used to simplify the variational wave functions. We present in detail the algorithm for efficient wave function optimization. We also present a Monte Carlo -based diagonalization technique to solve the quantum dot problem in the strong magnetic field limit where the system is of a multiconfiguration nature.Comment: 34 pages, proceedings of the 1st International Meeting on Advances in Computational Many-Body Physics, to appear in Journal of Low Temperature Physics (vol. 140, nos. 3/4

Fetal heart rate during a maternal grand mal epileptic seizure

Peer Reviewe

Voiding school as a treatment of daytime incontinence or enuresis : Children's experiences of the intervention

Background Daytime incontinence and enuresis are common problems in otherwise healthy children, and negatively influence their social lives and self-esteem. Motivation for treatment is often a real clinical problem. Children's experiences of their incontinence treatments have not been previously described. Objective The aim of this study was to describe children's experiences of the Voiding School intervention as a treatment for their incontinence. Study design A qualitative, descriptive focus-group study with a purposive sample was conducted at a Finish university hospital in 2014. Children aged 6-12 years participated in the Voiding School at an outpatient clinic. The intervention included two 1-day group visits 2 months apart. The educational content was based on the International Children Continence Society's standards for urotherapy. The education was delivered with child-oriented teaching methods. At the end of the second visit, 19 children were interviewed in five groups. Data were analysed with inductive content analysis. Results The children described incontinence as an embarrassing problem, which they had to hide at any cost. They had experienced bullying and social isolation because of it. Normal outpatient visits emphasized adult-to-adult communication, which made the children feel like outsiders. The children perceived the Voiding School as a nice and child-oriented experience. Making new friends was especially important to younger boys who felt that the Voiding School day was too long and issue-oriented. In the Voiding School, videos and 'learning by doing' helped the children to understand the basis of given advice, and they were able to learn new habits, which gave them control over the incontinence; this helped them to become 'the boss of the bladder'. Sharing experiences and improvements in their incontinence with their peers supported the children's self-esteem and encouraged them to do new things, such as staying overnight with friends. These experiences helped them to acquire control over the problem (Summary Figure). Discussion According to the children's experiences, normal outpatient visits were only appointments for adults, and not very useful for children. In the Voiding School, they were respected as being the main person, and their views were listened to. The results underlined the importance of a child-oriented approach to patient education with regard to children, and provided encouragement to further develop the intervention. Conclusion Child orientation, peer support, learning by doing, and understanding the cause and effect helped children to gain control over their bladders. Based on the children's experiences, this could be achieved by a voiding school.Peer reviewe

Student nurses’ experience of supervision and Mentorship in clinical practice: A cross cultural perspective

This paper reports a study, which explored student nurses experience in clinical practice. The aims of this study were to describe nurse education systems in clinical practice in eight nursing schools and compare the supervisory experiences of student nurses working in clinical settings. The nursing schools taking part in the study were members of the thematic european nursing network (TENN). A quantitative survey method was chosen for the method of this study. The sample (N=411) was collected using a validated research instrument from eight nursing schools participating in the TENN. The schools are located in Estonia, Belgium, Finland, Lithuania, Portugal, Romania, Turkey and United Kingdom. The data were collected during 2005. Although the nursing schools involved in TENN are in different development phases, however, the organisation of clinical practice is mainly similar. The percentage of clinical practice in a complete nursing programme varies from 38 to 57. Moreover, the duration of the clinical placements varies substantially across the nursing schools; from a couple weeks to 34 weeks. Students in this study evaluated their supervision experience positively. In three schools group or team supervision is the most common model. In the clinical placements where the pedagogical activities of staff nurses are notable, is a clear tendency towards a Mentorship model. However, approximately 10% of respondents perceived some practical problems in the organisation of Mentorship. Students' total satisfaction was observed to link with crucial variables but only connection with the variable Occurrence of supervision was statistically significant (p=0.000).info:eu-repo/semantics/publishedVersio

Stability of vortex structures in quantum dots

We study the stability and structure of vortices emerging in two-dimensional quantum dots in high magnetic fields. Our results obtained with exact diagonalization and density-functional calculations show that vortex structures can be found in various confining potentials. In nonsymmetric external potentials we find off-electron vortices that are localized giving rise to charge deficiency or holes in the electron density with rotating currents around them. We discuss the role of quantum fluctuations and show that vortex formation is observable in the energetics of the system. Our findings suggest that vortices can be used to characterize the solutions in high magnetic fields, giving insight into the underlying internal structure of the electronic wave function.Peer reviewe

On the lower bound on the exchange-correlation energy in two dimensions

We study the properties of the lower bound on the exchange-correlation energy in two dimensions. First we review the derivation of the bound and show how it can be written in a simple density-functional form. This form allows an explicit determination of the prefactor of the bound and testing its tightness. Next we focus on finite two-dimensional systems and examine how their distance from the bound depends on the system geometry. The results for the high-density limit suggest that a finite system that comes as close as possible to the ultimate bound on the exchange-correlation energy has circular geometry and a weak confining potential with a negative curvature

Size-segregated mass distributions of aerosols over Eastern Mediterranean: seasonal variability and comparison with AERONET columnar size-distributions

International audienceThis work provides long-term (2004?2006) size segregated measurements of aerosol mass at a remote coastal station in the southern Europe, with the use of size-selective samplings (SDI impactor). Seven distinct modes were identified in the range 0?10 µm and the dominant were the "Accumulation 1" (0.25?0.55 µm) and the "Coarse 2" (3?7 µm) modes. The seasonal characteristics of each mode were thoroughly studied and different sources for submicron and supermicron particles were identified, the first being related to local/regional and transported pollution with maximum in summer and the latter to dust from deserted areas in Northern Africa maximizing in spring. On average, PM2.5 and PM1 accounted for 60% and 40% of PM10 mass, respectively.The representativity of the ground-based measurements for the total column was also investigated by comparing the measured aerosol mass distributions with the AERONET volume size distribution data. Similar seasonal patterns were revealed and AERONET was found adequate for the estimation of background levels of both fine and coarse particles near surface, with certain limitations in the case of pollution or dust abrupt episodes due to its low temporal coverage