4,845 research outputs found
Correlations and charge distributions of medium heavy nuclei
The effects of long- and short-range correlations on the charge distributions
of some medium and heavy nuclei are investigated. The long-range correlations
are treated within the Random Phase Approximation framework and the short-range
correlations with a model inspired to the Correlation Basis Function theory.
The two type of correlations produce effects of the same order of magnitude. A
comparison with the empirical charge distribution difference between 206Pb and
205Tl shows the need of including both correlations to obtain a good
description of the data.Comment: 20 pages, Latex, accepted for publication in Jour. Phys.
One Body Density Matrix, Natural Orbits and Quasi Hole States in 16O and 40Ca
The one body density matrix, momentum distribution, natural orbits and quasi
hole states of 16O and 40Ca are analyzed in the framework of the correlated
basis function theory using state dependent correlations with central and
tensor components. Fermi hypernetted chain integral equations and single
operator chain approximation are employed to sum cluster diagrams at all
orders. The optimal trial wave function is determined by means of the
variational principle and the realistic Argonne v8' two-nucleon and Urbana IX
three-nucleon interactions. The correlated momentum distributions are in good
agreement with the available variational Monte Carlo results and show the well
known enhancement at large momentum values with respect to the independent
particle model. Diagonalization of the density matrix provides the natural
orbits and their occupation numbers. Correlations deplete the occupation number
of the first natural orbitals by more than 10%. The first following ones result
instead occupied by a few percent. Jastrow correlations lower the spectroscopic
factors of the valence states by a few percent (~1-3%) and an additional ~8-12%
depletion is provided by tensor correlations. It is confirmed that short range
correlations do not explain the spectroscopic factors extracted from (e,e'p)
experiments. 2h-1p perturbative corrections in the correlated basis are
expected to provide most of the remaining strength, as in nuclear matter.Comment: 25 pages, 9 figures. Submitted to Phys.Rev.
Ground state of N=Z doubly closed shell nuclei in CBF theory
The ground state properties of N=Z doubly closed shell nuclei are studied
within correlated basis function theory. A truncated version of the Urbana v14
realistic potential, with spin, isospin and tensor components, is adopted,
together with state dependent correlations. Fermi hypernetted chain integral
equation and single operator chain approximation are used to evaluate density,
distribution function and ground state energy of 16O and 40Ca. The results
favourably compare with the available, variational MonteCarlo estimates and
provide a first substantial check of the accuracy of the cluster summation
method for state dependent correlations. We achieve in finite nuclei at least
the same level of accuracy in the treatment of non central interactions and
correlations as in nuclear matter. This opens the way for a microscopic study
of medium heavy nuclei ground state using present days realistic hamiltonians.Comment: 35 pages (LateX) + 3 figures. Phys.Rev.C, in pres
Allergy sensitization and asthma among 13-14 year old school children in Nigeria
Background: The prevalence of asthma and role of atopy in asthma among children has not been clearly defined in Nigeria.Objective: To determine the prevalence of asthma and investigate risk factors related to allergy sensitization among urban and rural school children in southwest Nigeria.Methods: Validated ISAAC questionnaire was administered to 1736 high school children in randomly selected schools in rural and urban communities. Identified asthma cases were matched to controls. Allergy skin tests, blood eosinophil count, serum IgE and stool examination for parasites were performed. Dust samples from homes were also collected and analyzed for allergens.Results: The prevalence of asthma was 7.5% (95% CI 6.0 to 9.2%) and 8% (95% CI 6.0-10.4%) in the rural and urban communities respectively . Risk factors for asthma included cigarette-smoking, cats in the home and family size. Eosinophil count (109/L) was elevated in asthmatics [0.70 (95% CI 0.48-1.11) vs. 0.32 (95% CI 0.19-0.69); p<0.01], but IgE levels were similar between the two groups (298±229 IU/mL vs. 288±257; p=0.97). Positive skin tests to cat hair, cockroach, mango blossom and mouse epithelium were more frequent in asthmatics than in healthy controls, especially in the rural communities. There was no correlation between allergens in dust collected from homes and skin test reactivity.Conclusion: Asthma prevalence is similar in rural and urban children in Southwest Nigeria and atopy with elevated IgE was not observed to be a major factor for asthma in our cohort of children in both communities.Key words: Asthma, risk factors, prevalence, atopy, sensitization, childre
Inefficiencies in markets for intellectual property rights: experiences of academic and public research institutions
The formal use of such intellectual property rights (IPR) as patents and registered copyright by universities has increased steadily in the last two decades. Mainstream arguments, embedded in economic theory and policy, advocating the use of IPR to protect academic research results are based on the view that IPR marketplaces work well and allow universities to reap significant benefits. However, there is a lack of evidence-based research to justify or critically evaluate these claims. Building upon an original survey of 46 universities and public research organizations in the United Kingdom, this study analyses the quality of the institutions underpinning the markets for patents and copyright, investigating potential inefficiencies that could lead to underperformance of the IPR system. These include âIPR market failuresâ with respect to search processes and transparency; price negotiation processes; uncertainties in the perception of the economic value of IRP and the relationship with R&D cost. Further sources of underperformance may include âinstitutional failuresâ with respect to enforcement and regulation. Particular attention is paid to the role of governance forms (e.g. alternative types of licensing agreements) through which IPR exchanges take place. We find that a high share of universities report market failures in IPR transactions and that the choice of IPR governance forms matter for the obstacles that are encountered. Given the importance of widely disseminating university research outcomes to foster innovation and economic development, the presence of inefficiencies in IPR markets suggests that such objectives could best be achieved by encouraging open distribution of knowledge, rather than privatization of academic knowledge
The Remapping and Analysis of Human Rights and Peace Education in ASEAN / Southeast Asia (Philippine Report)
Human rights and peace education (HRPE) has never been more relevant for the Philippines. As of this writing, there have been opposing views and experiences on key national issues concerning human rights and peace in the country. There have also been apparent disagreements and malpractice with regards to human rights protection, as well as the proliferation of discourses, paradigms, and policies, that seem to trivialize and abuse human life and the rule of law. Therefore, it is imperative to strengthen HRPE and ensure that it is grounded on truth and what is happening at the grassroots level. Despite these challenges, this study shows that HRPE continues to evolve in the Philippine educational system. This study focuses on the current changes adopted by the Philippines with respect to human rights legal education, particularly the developments made by the Legal Education Board (LEB) from 2013 until late 2018. This is the area in which most of the developments are found. Peace and conflict-related programmes offered by colleges and universities are also explored in the study. Desk research on available curricula and programmes of higher education institutions (HEIs) was performed. If the data gathered through desk research were insufficient, necessary information was gathered through validation interviews. Key informant interviews were also conducted with Atty. Marian Chavez, the incumbent Executive Officer of the LEB; Atty. Tanya Karina Lat, one of the consultants of the LEB; and some students from various law schools around the country. The study also reviewed pertinent documents submitted to the LEB by the law schools, and the 2006 research study entitled, âBaseline Study of Law Schools: Human Rights Offerings and Programs Curriculum Review and Development Towards Alternative Lawyeringâ by Atty. Ma. Ngina Teresa V. Chan-Gonzaga.1 Qualitative analysis is used in analysing the recent developments in HRPE. To supplement the findings, the study also compares the current findings with those of the mapping report published in 2013.
La paralysie faciale pĂ©ripherique peut ĂȘtre une manifestation neurologique rĂ©vĂ©latrice de lâinfection Ă VIH
La paralysie faciale pĂ©riphĂ©rique (PFP) est une manifestation neurologique couramment rencontrĂ©e en consultation de neurochirurgie. Lâobjectif de cette Ă©tude a Ă©tĂ© de faire la corrĂ©lation entre cette affection et lâinfection Ă VIH sida. Il sâagit dâune Ă©tude rĂ©trospective dâoctobre 2008 Ă septembre 2012 qui a concernĂ© tous les patients prĂ©sentant une PFP en consultation de neurochirurgie. Les patients ont bĂ©nĂ©ficiĂ© dâun examen neurologique complet et dâexamens paracliniques sanguins, biologiques et radiologiques. Une consultation ORL a Ă©tĂ© effectuĂ©e pour tous les patients. Notre sĂ©rie comportait 36 patients dont 11 femmes. LâĂąge variait entre 20 ans et 42 ans. La paralysie faciale Ă©tait droite chez 22 patients (61,11%), la parĂ©sie intĂ©ressait toute lâhĂ©miface. Lâexamen Otorhinolaryngologique Ă©tait normal chez tous les patients tous comme le scanner cĂ©rĂ©bral. Dans notre sĂ©rie, 28 patients (77,77%) Ă©taient connus sĂ©ropositifs . LâElisa et le western blot ont confirmĂ© la prĂ©sence du VIH 1 chez tous les patients et du VIH 2 chez 8.. Le traitement a consistĂ© Ă lâadministration de prednisolone et des antirĂ©troviraux. LâĂ©volution a Ă©tĂ© favorable chez lâensemble des patients avec la disparition progressive de la paralysie faciale chez 20 patients en 3 mois et de 16 autres en 6 mois. La prĂ©sence du VIH 1 et 2 chez 77,77% des patients fait de la paralysie faciale un indicateur du VIH sida dans le dĂ©partement de neurochirurgie
Polyoptimisation of the aerodynamic and aeroacoustic performance of aerofoils with serrated leading edges
Recent research confirmed leading edge serrations to be an effective passive noise reduction treatment for aerofoil broadband noise at high-turbulent inflow conditions. Therefore, reducing leading edge broadband noise while maintaining acceptable aerodynamic aerofoil performance represents a pressing task for future applications. In this context, an extensive aeroacoustic study, analysing a NACA65(12)-10 aerofoil, was continued towards defining an aeroacoustic optimum between aerofoil noise radiation and noise reduction due to serrated leading edges in order to provide ideal design parameters for low-noise serrations. On this basis, part of the aeroacoustically analysed experimental space was extracted and analysed in terms of aerodynamic performance parameters, defined by lift and drag coefficients. This was carried out both, numerically and experimentally. The main parameters of interest were a variation of the Reynolds number, the angle of attack and the serration design parameters, namely the serration amplitude and the serration wavelength. The aerodynamic study showed a good match between experimental and numerical results in the pre-stall regime. Slight deviations occurred in a precise determination of the stall-angle and the maximum lift coefficients which mainly could be assigned to differing boundary conditions. However, for the serrations slight improvements of the maximum pre-stall angles as well as high post-stall lift coefficients were observed, which could be linked to specific separation pattern on the aerofoil suction side. An increase of the serration wavelength showed an increased lift performance, which could not be linked solely to a change in the aerofoils surface. Combining aeroacoustic and aerodynamic results showed that the aerodynamic trends towards a maximum lift performance compete aeroacoustic maximum-performance findings. Finally, defining a polyoptimum of the multi-parameter system in terms of maximum noise reduction effects while maintaining an acceptable aerodynamic performance provides a deepened insight into the relations between aerodynamics and aeroacoustics, where the presented data pool might give assistance for future design processes
Comparison of and Quasielastic Scattering
We formulate -nucleus quasielastic scattering in a manner which closely
parallels standard treatments of -nucleus quasielastic scattering. For
scattering, new responses involving scalar contributions appear in
addition to the Coulomb (or longitudinal) and transverse responses
which are of vector character. We compute these responses using both nuclear
matter and finite nucleus versions of the Relativistic Hartree Approximation to
Quantum Hadrodynamics including RPA correlations. Overall agreement with
measured responses and new quasielastic scattering data for
Ca at |\qs|=500 MeV/c is good. Strong RPA quenching is essential for
agreement with the Coulomb response. This quenching is notably less for the
cross section even though the new scalar contributions are even more
strongly quenched than the vector contributions. We show that this
``differential quenching'' alters sensitive cancellations in the expression for
the cross section so that it is reduced much less than the individual
responses. We emphasize the role of the purely relativistic distinction between
vector and scalar contributions in obtaining an accurate and consistent
description of the and data within the framework of our nuclear
structure model.Comment: 26 pages, 5 uuencoded figures appended to end of this fil
Thermodynamic Geometry and Phase Transitions in Kerr-Newman-AdS Black Holes
We investigate phase transitions and critical phenomena in Kerr-Newman-Anti
de Sitter black holes in the framework of the geometry of their equilibrium
thermodynamic state space. The scalar curvature of these state space Riemannian
geometries is computed in various ensembles. The scalar curvature diverges at
the critical point of second order phase transitions for these systems.
Remarkably, however, we show that the state space scalar curvature also carries
information about the liquid-gas like first order phase transitions and the
consequent instabilities and phase coexistence for these black holes. This is
encoded in the turning point behavior and the multi-valued branched structure
of the scalar curvature in the neighborhood of these first order phase
transitions. We re-examine this first for the conventional Van der Waals
system, as a preliminary exercise. Subsequently, we study the Kerr-Newman-AdS
black holes for a grand canonical and two "mixed" ensembles and establish novel
phase structures. The state space scalar curvature bears out our assertion for
the first order phase transitions for both the known and the new phase
structures, and closely resembles the Van der Waals system.Comment: 1 + 41 pages, LaTeX, 46 figures. Discussions, clarifications and
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