141 research outputs found

    Charge profile in vortices

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    The electric charge density in the vortex lattice of superconductors is studied within the Ginzburg-Landau theory. We show that the electrostatic potential Ļ•\phi is proportional to the GL function, Ļ•āˆāˆ£Ļˆāˆ£2āˆ’āˆ£Ļˆāˆžāˆ£2\phi\propto|\psi|^2-|\psi_\infty|^2. Numerical results for the triangular vortex lattice are presented.Comment: 4 pages with 2 figure

    Far-infrared magnetotransmission of YBa2(ZnxCu(1-x))3O(7-d)

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    Measurements of the far infrared magnetotransmission of YBa2(ZnxCu(1-x))3O(7-d) thin film (x = 0.025) deposited on a wedged MgO substrate are reported. The application of magnetic field perpendicular to the ab plane produces at low temperature a linear increase of transmission for frequencies below 30 cm-1. We present a model of high frequency vortex dynamics which qualitatively explains these results.Comment: 2 pages with 2 figures, presented on LT2

    Bernoulli potential at a superconductor surface

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    The electrostatic Bernoulli potential measured at the surface of a superconductor via Kelvin capacitive coupling is shown to be independent of the pairing mechanism. This contrasts with the Bernoulli potential in the bulk where contributions due to pairing dominate close to TcT_c.Comment: 2 page

    Temperature dependence of Vortex Charges in High Temperature Superconductors

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    Using a model Hamiltonian with d-wave superconductivity and competing antiferromagnetic (AF) interactions, the temperature (T) dependence of the vortex charge in high T_c superconductors is investigated by numerically solving the Bogoliubov-de Gennes equations. The strength of the induced AF order inside the vortex core is T dependent. The vortex charge could be negative when the AF order with sufficient strength is present at low temperatures. At higher temperatures, the AF order may be completely suppressed and the vortex charge becomes positive. A first order like transition in the T dependent vortex charge is seen near the critical temperature T_{AF}. For underdoped sample, the spatial profiles of the induced spin-density wave and charge-density wave orders could have stripe like structures at T < T_s, and change to two-dimensional isotropic ones at T > T_s. As a result, a vortex charge discontinuity occurs at T_s.Comment: 5 pages, 5 figure

    Charged Vortices in High Temperature Superconductors Probed by NMR

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    We report a first experimental evidence that a vortex in the high temperature superconductors (HTSC) traps a finite electric charge from the high resolution measurements of the nuclear quadrupole frequencies. In slightly overdoped YBa_2Cu_3O_7 the vortex is negatively charged by trapping electrons, while in underdoped YBa_2Cu_4O_8 it is positively charged by expelling electrons. The sign of the trapped charge is opposite to the sign predicted by the conventional BCS theory. Moreover, in both materials, the deviation of the magnitude of the charge from the theory is also significant. These unexpected features can be attributed to the novel electronic structure of the vortex in HTSC.Comment: 6 pages, 7 figures, to be published in Phys Rev.

    Early nutrition and adult health: Perspectives for international and community nutrition programs and policies

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    Recent economic changes throughout the world, either development or crises and recessions, have prompted a host of nutrition related problems, including a decreased prevalence of undernutrition, an increase in the prevalence of diet related diseases, widespread food insecurity as crop prices increase, and so on. In addition, evidence is mounting that suggests that exposure to poor nutrition early in life is a predisposing factor for chronic diseases in adulthood. Thus, the role of international or community nutrition professionals is vital to not only studying and understanding the interplay between economics, food policy, and health, but also to improving the ability to intervene and prevent many problems related to food insecurity in developed and developing countries. The purpose of this review is to outline and describe these issues as a means to open discussion on how to best alleviate major nutrition problems in the world

    Research priorities in pediatric parenteral nutrition: a consensus and perspective from ESPGHAN/ESPEN/ESPR/CSPEN

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    We acknowledge all the authors of the ESPGHAN/ESPR/ESPEN/CSPEN pediatric parenteral nutrition guidelines for their contributions and vote (Christian Braegger, University Childrenā€™s Hospital, Zurich, Switzerland; Jiri Bronsky, University Hospital Motol, Prague, Czech Republic; Cristina Campoy, Department of Paediatrics, School of Medicine, University of Granada, Granada, Spain; Magnus Domellof, Department of Clinical Sciences, Pediatrics, UmeĆ„ University, Sweden; Nicholas Embleton, Newcastle University, Newcastle upon Tyne, UK; Mary Fewtrell, UCL Great Ormond Street Institute of Child Health, London, UK; Natasa Fidler, University Medical Centre Ljubljana, Ljubljana, Slovenia; Axel Franz, University Childrenā€™s Hospital, Tuebingen, Germany; Oliver Goulet, University Sordonne-Paris-Cite; Paris-Descartes Medical School, Paris, France; Corina Hartmann, Schneider Childrenā€™s Medical Center of Israel, Petach Tikva, Israel and Carmel Medical Center, Israel; Susan Hill, Great Ormond Street Hospital for Children, NHS Foundation Trust and UCL Institute of Child Health, London, UK; Iva Hojsak, Childrenā€™s Hospital Zagreb, University of Zagreb School of Medicine, University of J. J. Strossmayer School of Medicine Osijek, Croatia; Sylvia Iacobelli, CHU La Reunion, Saint Pierre, France; Frank Jochum, Ev. Waldkrankenhaus Spandau, Berlin, Germany; Koen Joosten, Department of Pediatrics and Pediatric Surgery, Intensive Care, Erasmus MC Sophia Childrenā€™s Hospital, Rotterdam, The Netherlands; Sanja Kolacek, Childrenā€™s Hospital, University of Zagreb School of Medicine, Zagreb, Croatia; Alexandre Lapillone, Paris-Descartes University, Paris, France; Szimonetta Lohner, Department of Pediatrics, University of Pecs, Pecs, Hungary; Dieter Mesotten, KU Leuven, Leuven, Belgium; Walter Mihatsch, Ulm University, Ulm, and Helios Hospital, Pforzheim, Germany; Francis Mimouni, Department of Pediatrics, Division of Neonatology, The Wilf Childrenā€™s Hospital, the Shaare Zedek Medical Center, Jerusalem, and the Tel Aviv University, Tel Aviv, Israel; Christian Molgaard, Department of Nutrition, Exercise and Sports, University of Copenhagen, and Paediatric Nutrition Unit, Rigshospitalet, Copenhagen, Denmark; Sissel Moltu, Oslo University Hospital, Oslo, Norway; Antonia Nomayo, Ev. Waldkrankenhaus Spandau, Berlin, Germany; John Puntis, The General Infirmary at Leeds, Leeds, UK; Arieh Riskin, Bnai Zion Medical Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel; Miguel Saenz de Pipaon, Department of Neonatology, La Paz University Hospital, Red de Salud Materno Infantil y Desarrollo e SAMID, Universidad Autonoma de Madrid, Madrid, Spain; Raanan Shamir, Schneider Childrenā€™s Medical Center of Israel, Petach Tikva, Israel; Tel Aviv University, Tel Aviv, Israel; Peter Szitanyi, General University Hospital, First Faculty of Medicine, Charles University in Prague, Czech Republic; Merit Tabbers, Emma Childrenā€™s Hospital, Amsterdam UMC, Amsterdam, The Netherlands; Chris van den Akker, Emma Childrenā€™s Hospital, Amsterdam UMC, Amsterdam, The Netherlands; Hans van Goudoever, Emma Childrenā€™s Hospital, Amsterdam UMC, Amsterdam, The Netherlands; Sacha Verbruggen, Department of Pediatrics and Pediatric Surgery, Intensive Care, Erasmus MC-Sophia Childrenā€™s Hospital, Rotterdam, The Netherlands; Cai Wei, Shanghai Jiao Tong University, Shanghai, China; Weihui Yan, Department of Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China) and the members of the ESPR Section on Nutrition, Gastroenterology and Metabolism (Fredrik Ahlsson, Uppsala University Childrenā€™s Hospital and Department of Womenā€™s and Childrenā€™s Health, Uppsala University, Uppsala, Sweden; Sertac Arslanoglu, Division of Neonatology, Department of Pediatrics, Istanbul Medeniyet University, Istanbul, Turkey; Wolfgang Bernhard, Department of Neonatology, Childrenā€™s Hospital, Faculty of Medicine, Eberhard-Karls- University, TĆ¼bingen, Germany; Janet Berrington, Newcastle Neonatal Service, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Signe Bruun, Hans Christian Andersen Hospital for Children and Adolescents, Odense University Hospital, Odense, Denmark; Christoph Fusch, Department of Pediatrics, Paracelsus Medical School, General Hospital of Nuremberg, Nuremberg, Germany; Shalabh Garg, South Tees Hospitals, Middlesborough, UK; Maria Gianni, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy; Ann Hellstrom, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden; Claus Klingenberg, Department of Pediatrics and Adolescence Medicine, University Hospital of North Norway, TromsĆø, Norway; Helen Mactier, Neonatal Unit, Princess Royal Maternity Hospital, Glasgow, UK; Neena Modi, Section of Neonatal Medicine, Department of Medicine, Chelsea and Westminster Campus, Imperial College London, London, UK; Niels Rochow, Division of Neonatology, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada; Paola Rogerro, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy; Umberto Simeoni, Division of Pediatrics, CHUV & University of Lausanne, Lausanne, Switzerland; Atul Singhal, Paediatric Nutrition, UCL Great Ormond Street Institute of Child Health, London, UK.; Ulrich Thome, Department of Neonatology, Universitatsklinikum Leipzig, Leipzig, Germany; Anne Twomey, Department of Neonatology, The National Maternity Hospital, Dublin, Ireland; Mireille Vanpee, Karolinska University Hospital, Stockholm, Sweden; Gitte Zachariassen, Hans Christian Andersen Hospital for Children and Adolescents, Odense University Hospital, Odense, Denmark) for their vote.Parenteral nutrition is used to treat children that cannot be fully fed by the enteral route. While the revised ESPGHAN/ ESPEN/ESPR/CSPEN pediatric parenteral nutrition guidelines provide clear guidance on the use of parenteral nutrition in neonates, infants, and children based on current available evidence, they have helped to crystallize areas where research is lacking or more studies are needed in order to refine recommendations. This paper collates and discusses the research gaps identified by the authors of each section of the guidelines and considers each nutrient or group of nutrients in turn, together with aspects around delivery and organization. The 99 research priorities identified were then ranked in order of importance by clinicians and researchers working in the field using a survey methodology. The highest ranked priority was the need to understand the relationship between total energy intake, rapid catch-up growth, later metabolic function, and neurocognitive outcomes. Research into the optimal intakes of macronutrients needed in order to achieve optimal outcomes also featured prominently. Identifying research priorities in PN should enable research to be focussed on addressing key issues. Multicentre trials, better definition of exposure and outcome variables, and long-term metabolic and developmental follow-up will be key to achieving this

    Chronic Intestinal Failure in Children: An International Multicenter Cross-Sectional Survey

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    Background: The European Society for Clinical Nutrition and Metabolism database for chronic intestinal failure (CIF) was analyzed to investigate factors associated with nutritional status and the intravenous supplementation (IVS) dependency in children. Methods: Data collected: demographics, CIF mechanism, home parenteral nutrition program, z-scores of weight-for-age (WFA), length or height-for-age (LFA/HFA), and body mass index-for-age (BMI-FA). IVS dependency was calculated as the ratio of daily total IVS energy over estimated resting energy expenditure (%IVSE/REE). Results: Five hundred and fifty-eight patients were included, 57.2% of whom were male. CIF mechanisms at age 1ā€“4 and 14ā€“18 years, respectively: SBS 63.3%, 37.9%; dysmotility or mucosal disease: 36.7%, 62.1%. One-third had WFA and/or LFA/HFA z-scores &lt; āˆ’2. One-third had %IVSE/REE &gt; 125%. Multivariate analysis showed that mechanism of CIF was associated with WFA and/or LFA/HFA z-scores (negatively with mucosal disease) and %IVSE/REE (higher for dysmotility and lower in SBS with colon in continuity), while z-scores were negatively associated with %IVSE/REE. Conclusions: The main mechanism of CIF at young age was short bowel syndrome (SBS), whereas most patients facing adulthood had intestinal dysmotility or mucosal disease. One-third were underweight or stunted and had high IVS dependency. Considering that IVS dependency was associated with both CIF mechanisms and nutritional status, IVS dependency is suggested as a potential marker for CIF severity in children
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