Neutron Transfer reactions induced by 8Li on 9Be

Angular distributions for the elastic scattering of 8Li on 9Be and the neutron transfer reactions 9Be(8Li,7Li)10Be and 9Be(8Li,9Li)8Be have been measured with a 27 MeV 8Li radioactive nuclear beam. Spectroscopic factors for 8Li|n=9Li and 7Li|n=8Li bound systems were obtained from the comparison between the experimental differential cross section and finite-range DWBA calculations with the code FRESCO. The spectroscopic factors obtained are compared to shell model calculations and to other experimental values from (d,p) reactions. Using the present values for the spectroscopic factor, cross sections for the direct neutron-capture reactions 7Li(n,g)8Li and 8Li(n,g)9Li were calculated in the framework of a potential model.Comment: 24 pages, 8 Figures, submitted as regular article to PR

Formation of convective cells in the scrape-off layer of the CASTOR tokamak

Understanding of the scrape-off layer (SOL) physics in tokamaks requires diagnostics with sufficient temporal and spatial resolution. This contribution describes results of experiments performed in the SOL of the CASTOR tokamak (R=40 cm, a = 6 cm) by means of a ring of 124 Langmuir probes surrounding the whole poloidal cross section. The individual probes measure either the ion saturation current of the floating potential with the spatial resolution up to 3 mm. Experiments are performed in a particular magnetic configuration, characterized by a long parallel connection length in the SOL, L_par ~q2piR. We report on measurements in discharges, where the edge electric field is modified by inserting a biased electrode into the edge plasma. In particular, a complex picture is observed, if the biased electrode is located inside the SOL. The poloidal distribution of the floating potential appears to be strongly non-uniform at biasing. The peaks of potential are observed at particular poloidal angles. This is interpreted as formation of a biased flux tube, which emanates from the electrode along the magnetic field lines and snakes q times around the torus. The resulting electric field in the SOL is 2-dimensional, having the radial as well as the poloidal component. It is demonstrated that the poloidal electric field E_pol convects the edge plasma radially due to the E_pol x B_T drift either inward or outward depending on its sign. The convective particle flux is by two orders of magnitude larger than the fluctuation-induced one and consequently dominates.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

To what extent can dynamical models describe statistical features of turbulent flows?

Statistical features of "bursty" behaviour in charged and neutral fluid turbulence, are compared to statistics of intermittent events in a GOY shell model, and avalanches in different models of Self Organized Criticality (SOC). It is found that inter-burst times show a power law distribution for turbulent samples and for the shell model, a property which is shared only in a particular case of the running sandpile model. The breakdown of self-similarity generated by isolated events observed in the turbulent samples, is well reproduced by the shell model, while it is absent in all SOC models considered. On this base, we conclude that SOC models are not adequate to mimic fluid turbulence, while the GOY shell model constitutes a better candidate to describe the gross features of turbulence.Comment: 14 pages, 4 figures, in press on Europhys. Lett. (may 2002

Theory for Dynamical Short Range Order and Fermi Surface Volume in Strongly Correlated Systems

Using the fluctuation exchange approximation of the one band Hubbard model, we discuss the origin of the changing Fermi surface volume in underdoped cuprate systems due to the transfer of occupied states from the Fermi surface to its shadow, resulting from the strong dynamical antiferromagnetic short range correlations. The momentum and temperature dependence of the quasi particle scattering rate shows unusual deviations from the conventional Fermi liquid like behavior. Their consequences for the changing Fermi surface volume are discussed. Here, we investigate in detail which scattering processes might be responsible for a violation of the Luttinger theorem. Finally, we discuss the formation of hole pockets near half filling.Comment: 5 pages, Revtex, 4 postscript figure

Allogeneic mesenchymal stem cells improve the wound healing process of sheep skin

Abstract Background Skin wound healing includes a system of biological processes, collectively restoring the integrity of the skin after injury. Healing by second intention refers to repair of large and deep wounds where the tissue edges cannot be approximated and substantial scarring is often observed. The objective of this study was to evaluate the effects of mesenchymal stem cells (MSCs) in second intention healing using a surgical wound model in sheep. MSCs are known to contribute to the inflammatory, proliferative, and remodeling phases of the skin regeneration process in rodent models, but data are lacking for large animal models. This study used three different approaches (clinical, histopathological, and molecular analysis) to assess the putative action of allogeneic MSCs at 15 and 42 days after lesion creation. Results At 15 days post-lesion, the wounds treated with MSCs showed a higher degree of wound closure, a higher percentage of re-epithelialization, proliferation, neovascularization and increased contraction in comparison to a control group. At 42 days, the wounds treated with MSCs had more mature and denser cutaneous adnexa compared to the control group. The MSCs-treated group showed an absence of inflammation and expression of CD3+ and CD20+. Moreover, the mRNA expression of hair-keratine (hKER) was observed in the MSCs-treated group 15 days after wound creation and had increased significantly by 42 days post-wound creation. Collagen1 gene (Col1α1) expression was also greater in the MSCs-treated group compared to the control group at both days 15 and 42. Conclusion Peripheral blood-derived MSCs may improve the quality of wound healing both for superficial injuries and deep lesions. MSCs did not induce an inflammatory response and accelerated the appearance of granulation tissue, neovascularization, structural proteins, and skin adnexa

Measurements of plasma potential and electron temperature by ball-pen probes in RFX-mod

The ball-pen probe (BPP) is an innovative electric probe for direct measurements of the plasma potential. This probe was developed in IPP Prague and it is based on the Katsumata probe concept. Combined measurements of the plasma potential by a BPP and floating potential by a Langmuir probe provide also the value of the electron temperature. First test of the BPP on the RFX-mod reversed field pinch in Padova has been performed in November 2006. The BPP head, made of boron nitride, is equipped with four graphite collectors, which are positioned at four different radial positions h inside four shafts hollow into the probe head. The radial profile of the plasma potential and also the electron temperature were measured.Кулеподібний зонд – новий тип зонду для прямих вимірюаннь потенціалу плазми. Цей зонд розроблено у ІТП, в Празі, та засновано на концепції зонду Катсумати. Комбіновані вимірювання плазмового потенцілу кулеподібним зондом та плаваючого потенціалу Ленгмюрівським зондом дають також величину електронної температури. Перші випробування зонду в пінчі з оберненим полем на RFX-mod у Падові було проведено у листопаді 2006 р. Головка зонда, вироблена з нітриду бора, була оснащена чотирма графітовими колекторами, які були розташовані в чотирьох радіальних положеннях h усередині чотирьох порожнистих циліндричних отворів в голівці зонда. Виміряно радіальний профіль потенціалу плазми й електронну температуру.Шароподобный зонд – новый тип зонда для прямых измерений потенциала плазмы. Данный зонд разработан в ИФП, в Праге, и основан на концепции зонда Катсуматы. Комбинированные измерения плазменного потенциала шароподобным зондом и плавающего потенциала Ленгмюровским зондом дают также величину электронной температуры. Первые испытания зонда в пинче с обращенным полем на RFX-mod в Падове проведены в ноябре 2006 г. Головка зонда, сделанная из нитрида бора, оснащалась четырьмя графитовыми коллекторами, которые размещались в четырех различных радиальных положениях h внутри четырех пустотелых цилиндрических отверстий в головке зонда. Измерены радиальный профиль потенциала плазмы и электронная температура

Electromagnetic turbulent structures: A ubiquitous feature of the edge region of toroidal plasma configurations

Electromagnetic features of turbulent filaments, emerging from a turbulent plasma background, have been studied in four different magnetic configurations: the stellarator TJ-II, the Reversed Field Pinch RFX-mod, a device that can be operated also as a ohmic tokamak, and the Simple Magnetized Torus, TORPEX. By applying an analogous diagnostic concept in all cases, direct measurements of both field-aligned current density and vorticity were performed inside the filament. The inter-machine comparison reveals a clear dependence of the filament vorticity upon the local time-averaged E x B flow shear. Furthermore, a wide range of local beta was explored allowing concluding that this parameter plays a fundamental role in the appearance of filament electromagnetic features

National and sub-national under-five mortality profiles in Peru: a basis for informed policy decisions

BACKGROUND: Information on profiles for under-five causes of death is important to guide choice of child-survival interventions. Global level data have been published, but information at country level is scarce. We aimed at defining national and departmental trends and profiles of under-five mortality in Peru from 1996 through 2000. METHODS: We used the Ministry of Health registered under-five mortality data. For correction of under-registration, a model life-table that fitted the age distribution of the population and of registered deaths was identified for each year. The mortality rates corresponding to these model life-tables were then assigned to each department in each particular year. Cumulative reduction in under-five mortality rate in the 1996–2000 period was estimated calculating the annual reduction slope for each department. Departmental level mortality profiles were constructed. Differences in mortality profiles and in mortality reduction between coastal, andean and jungle regions were also assessed. RESULTS: At country level, only 4 causes (pneumonia, diarrhoea, neonatal diseases and injuries) accounted for 68% of all deaths in 1996, and for 62% in 2000. There was 32.7% of under-five death reduction from 1996 to 2000. Diarrhoea and pneumonia deaths decreased by 84.5% and 41.8%, respectively, mainly in the andean region, whereas deaths due to neonatal causes and injuries decreased by 37.2% and 21.7%. For 1996–2000 period, the andean, coast and jungle regions accounted for 52.4%, 33.1% and 14.4% of deaths, respectively. These regions represent 41.0%, 46.4% and 12.6% of under-five population. Both diarrhoea and pneumonia constitute 30.6% of under-five deaths in the andean region. As a proportion, neonatal deaths remained stable in the country from 1996 to 2000, accounting for about 30% of under-five deaths, whereas injuries and "other" causes, including congenital anomalies, increased by about 5%. CONCLUSION: Under-five mortality declined substantially in all departments from 1996 to 2000, which is explained mostly by reduction in diarrhoea and pneumonia deaths, particularly in the andean region. There is the need to emphasize interventions to reduce neonatal deaths and emerging causes of death such as injuries and congenital anomalies

Results of a multi-country exploratory survey of approaches and methods for IMCI case management training

<p>Abstract</p> <p>Background</p> <p>The Integrated Management of Childhood Illness Strategy (IMCI) is effective in improving management of sick children, and thus child survival. It is currently recommended that in-service IMCI case management training (ICMT) occur over 11-days; that the participant: facilitator ratio should be ≤4:1 and that at least 30% of ICMT time be spent on clinical practice. In 2006–2007, approximately ten years after IMCI implementation, we conducted a multi-country exploratory questionnaire survey to document country experiences with ICMT, and to determine the acceptability of shortening duration of ICMT.</p> <p>Methods</p> <p>Questionnaires (QA) were sent to national IMCI focal persons in 27 purposively-selected countries. To probe further, questionnaires (QB and QC respectively) were also sent to course-directors or facilitators and IMCI trainees, selected using snowball sampling after applying pre-defined criteria, in these countries. Questionnaires gathered quantitative and qualitative data.</p> <p>Results</p> <p>Thirty-three QA, 163 QB, 272 QC and two summaries were returned from 24 countries. All countries continued to adapt course content to local disease burden. All countries offer shorter ICMT courses, ranging from 3–10 days (commonest being 5–8 days). The shorter ICMT courses offer fewer exercises, more homework, less individual feedback and reduced clinical practice (<30% time). Whereas changes to course content were usually evidence-based, changes to training methodology and course duration evolved as pressure to expand implementation mounted. Participants varied in their self-reported skill and perception about each course. However, the varied methodology and integrated approach to management of illnesses were commonly cited as strengths of ICMT, and the chart booklet and clinical practice sessions were identified as critical components of ICMT. Four themes emerged from the qualitative work, viz. the current 11-day course is too expensive and should be shortened; advocacy around IMCI should increase; content should be regularly updated, new content areas should be introduced cautiously and more attention should be paid to skills-building rather than knowledge accumulation.</p> <p>Conclusion</p> <p>Whilst the 11-day ICMT course is still recommended, as efforts intensify to increase access to quality care and meet MDG4, standardized shorter ICMT courses, that include participatory methodologies and adequate clinical practice, could be acceptable globally.</p