Dynamic splitting of a Bose-Einstein Condensate

We study the dynamic process of splitting a condensate by raising a potential barrier in the center of a harmonic trap. We use a two-mode model to describe the phase coherence between the two halves of the condensate. Furthermore, we explicitly consider the spatial dependence of the mode funtions, which varies depending on the potential barrier. This allows to get the tunneling coupling between the two wells and the on-site energy as a function of the barrier height. Moreover we can get some insight on the collective modes which are excited by raising the barrier. We describe the internal and external degrees of freedom by variational ansatz. We distinguish the possible regimes as a function of the characteristic parameters of the problem and identify the adiabaticity conditions.Comment: 17 pages, 8 figure

Coherent dynamics of Bose-Einstein condensates in high-finesse optical cavities

We study the mutual interaction of a Bose-Einstein condensed gas with a single mode of a high-finesse optical cavity. We show how the cavity transmission reflects condensate properties and calculate the self-consistent intra-cavity light field and condensate evolution. Solving the coupled condensate-cavity equations we find that while falling through the cavity, the condensate is adiabatically transfered into the ground state of the periodic optical potential. This allows time dependent non-destructive measurements on Bose-Einstein condensates with intriguing prospects for subsequent controlled manipulation.Comment: 5 pages, 5 figures; revised version: added reference

Dynamics of tournaments: the soccer case

A random walk-like model is considered to discuss statistical aspects of tournaments. The model is applied to soccer leagues with emphasis on the scores. This competitive system was computationally simulated and the results are compared with empirical data from the English, the German and the Spanish leagues and showed a good agreement with them. The present approach enabled us to characterize a diffusion where the scores are not normally distributed, having a short and asymmetric tail extending towards more positive values. We argue that this non-Gaussian behavior is related with the difference between the teams and with the asymmetry of the scores system. In addition, we compared two tournament systems: the all-play-all and the elimination tournaments.Comment: To appear in EPJ

Breastfeeding practice in mothers with eating disorders

The purpose of this study was to compare the prevalence of breastfeeding in women with anorexia nervosa, bulimia nervosa, binge eating disorder and eating disorders not otherwise specified - purging subtype, with mothers with no eating disorders during the first 6 months after birth. The study is based on the Norwegian Mother and Child Cohort Study conducted at the Norwegian Institute of Public Health. Questionnaire-based information on eating disorder diagnoses and breastfeeding in 39 355 women was used to estimate the risk of cessation of breastfeeding with Cox proportional hazards regression. Almost all women (98%) initially breastfeed their infants, with no statistically significant difference between the eating disorders subgroups and women with no eating disorders. However, the risk of early cessation before 6 months post-partum increased for all subgroups of mothers with eating disorders, compared with mothers with no eating disorders. After adjusting for maternal body mass index, age, education, birthweight and pre-term birth, only mothers with anorexia nervosa [hazard ratios (HR), 2.35; 95% confidence interval (CI) 1.22-4.53] and eating disorder not otherwise specified-purging subtype (HR, 1.95; 95% CI 1.08-3.53) had increased risk for cessation of breastfeeding There were no differences in the risk of cessation of exclusive breastfeeding. These results show that some eating disorders may influence mothers' early feeding practices and indicate that additional support may be necessary to assist women with anorexia nervosa in maintaining breastfeeding

Migration of chemotactic bacteria in soft agar: role of gel concentration

We study the migration of chemotactic wild-type Escherichia coli populations in semisolid (soft) agar in the concentration range C = 0.15-0.5% (w/v). For C < 0.35%, expanding bacterial colonies display characteristic chemotactic rings. At C = 0.35%, however, bacteria migrate as broad circular bands rather than sharp rings. These are growth/diffusion waves arising because of suppression of chemotaxis by the agar and have not been previously reported experimentally to our knowledge. For C = 0.4-0.5%, expanding colonies do not span the depth of the agar and develop pronounced front instabilities. The migration front speed is weakly dependent on agar concentration at C < 0.25%, but decreases sharply above this value. We discuss these observations in terms of an extended Keller-Segel model for which we derived novel transport parameter expressions accounting for perturbations of the chemotactic response by collisions with the agar. The model makes it possible to fit the observed front speed decay in the range C = 0.15-0.35%, and its solutions qualitatively reproduce the observed transition from chemotactic to growth/diffusion bands. We discuss the implications of our results for the study of bacteria in porous media and for the design of improved bacteriological chemotaxis assays.Comment: 28 pages, 5 figures. Published online at http://www.sciencedirect.com/science/article/pii/S000634951100721

Reduced Oct4 expression directs a robust pluripotent state with distinct signaling activity and increased enhancer occupancy by Oct4 and Nanog

10.1016/j.stem.2013.04.023Cell Stem Cell125531-54

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

A Systematic Review of Neuropsychological Tests for the Assessment of Dementia in Non-Western, Low-Educated or Illiterate Populations

Objective:Neuropsychological tests are important instruments to determine a cognitive profile, giving insight into the etiology of dementia; however, these tests cannot readily be used in culturally diverse, low-educated populations, due to their dependence upon (Western) culture, education, and literacy. In this review we aim to give an overview of studies investigating domain-specific cognitive tests used to assess dementia in non-Western, low-educated populations. The second aim was to examine the quality of these studies and of the adaptations for culturally, linguistically, and educationally diverse populations.Method:A systematic review was performed using six databases, without restrictions on the year or language of publication.Results:Forty-four studies were included, stemming mainly from Brazil, Hong Kong, Korea, and considering Hispanics/Latinos residing in the USA. Most studies focused on Alzheimer's disease (n = 17) or unspecified dementia (n = 16). Memory (n = 18) was studied most often, using 14 different tests. The traditional Western tests in the domains of attention (n = 8) and construction (n = 15), were unsuitable for low-educated patients. There was little variety in instruments measuring executive functioning (two tests, n = 13), and language (n = 12, of which 10 were naming tests). Many studies did not report a thorough adaptation procedure (n = 39) or blinding procedures (n = 29).Conclusions:Various formats of memory tests seem suitable for low-educated, non-Western populations. Promising tasks in other cognitive domains are the Stick Design Test, Five Digit Test, and verbal fluency test. Further research is needed regarding cross-cultural instruments measuring executive functioning and language in low-educated people

Escherichia coli as a model active colloid:A practical introduction

The flagellated bacterium Escherichia coli is increasingly used experimentally as a self-propelled swimmer. To obtain meaningful, quantitative results that are comparable between different laboratories, reproducible protocols are needed to control, `tune' and monitor the swimming behaviour of these motile cells. We critically review the knowledge needed to do so, explain methods for characterising the colloidal and motile properties of E.coli, cells, and propose a protocol for keeping them swimming at constant speed at finite bulk concentrations. In the process of establishing this protocol, we use motility as a high-throughput probe of aspects of cellular physiology via the coupling between swimming speed and the proton motive force.Comment: 18 pages, 16 figures, 4 table