1,157 research outputs found
The once & future repository, HKU's Scholars Hub
The HKU Scholars Hub (the Hub) began service as a traditional institutional repository of The University of Hong Kong (HKU). However this format was not compelling to HKU researchers. Fortunately a subsequent reformation of the HKU statement on university mission and vision infused new life and purpose into the project. Over the next five years, in partnership with the Italian University Consortium, Cineca, the HKU Libraries transformed the Hub from an IR to a Current Research Information System. We expect that future development will see the Hub further transformed into a research information management system supporting both internal decision support and external public discovery. We will present new work developed recently to further these goals.
IRs collect, manage and display publications, and their metadata. However, an institution’s research, expertise and capacity is described by more than publications. The Hub, hosted in DSpace, began as the IR of HKU in 2005. Asking for voluntary deposit of publications from HKU academics, it received little notice, and more importantly, little support from University senior management. In 2009 a new HKU initiative, Knowledge Exchange (KE), adopted the Hub as a key vehicle to share knowledge and skill with the community outside HKU. Upon winning grant support from the office of KE, the HKU Libraries chose Cineca as a development partner. Together we designed specifications to extend the data model of DSpace. We architected solutions to support non-publication objects, including people, grants, and patents. These entities are managed in new database tables with a flexible structure that is able to hold indexed and interlinked attributes, such as co-investigators, co-inventors, co-prize winners, research interests, languages spoken, supervision of postgraduate theses, etc. The structure has been designed to provide native support (through a backend UI) to the data model extensions. This will allow local operators to easily add new entities and new attributes, interlinkable to any internal or external corresponding record, without the need to write new code.
Beginning with local data in several HKU silos, scripts will search for corresponding or augmented records in external sources, harvest and merge with Hub data. These sources are publication databases (Scopus, WoS, PubMed, etc.), funders (Hong Kong Research Grants Council, NIH, etc), patents (USPTO, Espacenet, Japan Patent Office, etc), and bibliometrics (Scopus, Google Scholar Citations, SSRN, etc).
The DSpace user interface now delivers an integrated search and display on all objects and attributes, as well as on ones newly derived, such as a) authority work on name disambiguation and synonymy in Roman and Hanzi (漢字), b) visualizations on networks of co-authors, co-investigators, etc, c) metrics extracted from external sources, and d) internal alt-metrics of view and download counts, and more.
In order to increase utility and the interchange of information, we have augmented DSpace’s OAI-PMH with several other protocols. 1) DOI. We register DOI numbers with CrossRef for all our e-theses (23,000 in 2015), and will begin sending separate XML delineated bibliographies to CrossRef to allow us to harvest citation counts from CrossRef. 2) ORCID. As an early adopter of ORCID, we have created ORCID accounts and populated them with data from the Hub for all our professoriate staff. During the OR2015 Meeting we will present the new developments made in collaboration with Cineca that have brought DSpace integration with ORCID to a new level: using the extended data model for DSpace described above, we are developing scripts to automatically query the scholar when new information comes into the Hub. Upon this scholar’s confirming one click, the script will automatically update the ORCID account. A similar future script, upon the scholar’s one click, will create and populate an ORCID account with information harvested from the Hub. 3) CERIF. We will soon implement the Common European Research Information Format (CERIF), for data exchange with other research entities. The Catalan Consortium and CSIC (mentioned below) have now used CERIF in this context to build central repositories.
Beyond the open scholarship functions of an IR, the Hub now performs as a system for reputation management, impact management, and research networking and profiling -- all of which are concepts included in the broad term, “Current Research Information System” (CRIS). These new objects and attributes curated from several trusted sources, and integrated into the present mashup, contextualize and highlight HKU research, and attract more hits, than an IR with only publications. A CRIS can provide discovery on internal resources to external users, and decision support to internal administration. Linked CRISes across several organizations or countries, using a common data interchange format such as CERIF, on top of providing federated discovery, can provide the sociological and organizational functions needed in e-science, e-research and cyberinfrastructure projects.
The Hub has repurposed data once held in dark archives for HKU in-house administration purposes only. This data, after augmentation by the Libraries, provides discovery on HKU research and expertise. This data is then further harvested from the Hub for a multitude of purposes. HKU faculties are slowly abandoning their own data collection and web page creation methods in favour of using the web service of the Hub, to extract any Hub displayed element into XML. We re-package our data to ship to SSRN, so that the HKU Law Faculty can provide a monthly journal in SSRN’s LSN, etc. The Hub also enables the repurposing of Library staff. With the demise of print cataloguing, several staff found themselves without a job. Verifying, augmenting, and curating data incoming to the Hub has provided these staff with continuing and richer employment. And, the Hub project has newly purposed the HKU Libraries with another means of supporting their underlying institution. This is much welcomed in this era of lessened importance of the onsite physical collection.
Using grant funding from the HKU Office of Knowledge Exchange, Cineca and HKU Libraries modularized this development work and placed it in open source on GitHub, with the name, “DSpace-CRIS”. Any DSpace site can now download and install as an optional add-on to DSpace. The Catalan Consortium of Research Universities has used it to build a regional portal that aggregates research information from all Universities in their region. EuroCRIS has used it for publication management and researcher profiles on their member organizations. Sites of other uptake include the Hong Kong Polytechnic University and the CSIC Consejo Superior de Investigaciones Científicas (Spanish National Research Council). In recognition of DSpace-CRIS’ great flexibility, potential, and cost effectiveness, Cineca adopted DSpace-CRIS as the basis for their new “IRIS”, an enterprise CRIS platform which they are now installing in over 60 universities in Italy and abroad. A separate proposal to OR 2015 will give further detail on this.
The new version of DSpace-CRIS that we will present at OR2015, besides the important update relating to ORCID integration above described, includes a reworked search interface. We are introducing a new global search across all entities managed by the system to give surgical precision in search and discovery. These searches will return snippets of text with search terms highlighted in context. The DSpace-CRIS repository eco-system is now very rich. As an example, the researcher’s profile is composed of more than ten different sections covering general contact information, publications, projects, bibliometrics, theses, etc. Clicking on the returned highlighted search terms in context will take the user to the exact section where the desired information is displayed, rather than dropping the searcher confusingly at the top of a long complex record. This new global search will also enable operators to easily make new reports showing correspondence between data elements in disparate Hub entities, such as an interactive “Faculty Used Journals for Publications Report”, sortable by publication frequency, impact factor, year, author, underlying grant scheme, patents generated, etc.
In summary, all involved with DSpace-CRIS wish to move this project further, to increase the utility of DSpace-CRIS, and its adoption in the open source community. We hope to find new ways to work with DuraSpace. This could mean providing a road map to the future for libraries stalled in IR development. It could mean providing an open source solution for IR / CRIS, as an alternative to commercial products. We would very much like to work with the community to find ways of convergence, DSpace-CRIS with mainstream DSpace. IRs and CRISes are changing, and their users and administrators are asking for new types of information and new ways to use them. We wish to fully collaborate with DuraSpace, to define a vision of the future, and make it happen for everyone that wishes this collaboration.published_or_final_versio
Numerical simulation of the flexural behaviour of composite glass-GFRP beams using smeared crack models
This paper presents a numerical study about the flexural behaviour of rectangular composite glass-GFRP beams, comprising annealed glass and GFRP pultruded profiles bonded with two different adhesives: (soft) polyurethane and (stiff) epoxy. The main objectives of this study were: (i) to fully characterize the non-linear behaviour of glass using the smeared crack approach; and (ii) to assess the applicability of different options to simulate adhesively bonded glass-GFRP joints. An extensive parametric study was developed to evaluate the influence of five parameters on the glass post-cracking non-linear behaviour: (i) glass fracture energy, Gf, (ii) crack band width, h, (iii) glass tensile strength, fg,t, (iv) shape of the tension-softening diagram, and (v) shear retention factor, β. The wide range of the joints’ shear stiffness was simulated by either (i) assuming a perfect bond between glass and GFRP (i.e., neglecting the presence of the adhesive), or (ii) explicitly considering the adhesive, by means of using (ii.1) plane stress elements, or (ii.2) interface elements. For the beams analysed in this paper, the following material model for glass provided a good agreement with experimental results: Gf in the range of 3 to 300 N/m, h equal to the square root of the finite element area, fg,t = 50 MPa, linear softening diagram and β according to a power law. It was also shown that the hypothesis of perfect bond at the GFRP-glass interfaces allows for an accurate simulation of joints with high levels of interaction (epoxy), while calibrated interface elements are needed for joints with low level of interaction (polyurethane).The authors wish to acknowledge FCT, ICIST/CERIS and ISISE for funding the research, and
companies SIKA, Guardian and ALTO for supplying the adhesives, the glass panes and the GFRP
pultruded profiles used in the experiments. The first author also wishes to thank FCT for the financial
support through his PhD scholarship SFRH/BD/80234/2011
Stringy effects in black hole decay
We compute the low energy decay rates of near-extremal three(four) charge
black holes in five(four) dimensional N=4 string theory to sub-leading order in
the large charge approximation. This involves studying stringy corrections to
scattering amplitudes of a scalar field off a black hole. We adapt and use
recently developed techniques to compute such amplitudes as near-horizon
quantities. We then compare this with the corresponding calculation in the
microscopic configuration carrying the same charges as the black hole. We find
perfect agreement between the microscopic and macroscopic calculations; in the
cases we study, the zero energy limit of the scattering cross section is equal
to four times the Wald entropy of the black hole.Comment: 32 page
Degenerate Rotating Black Holes, Chiral CFTs and Fermi Surfaces I - Analytic Results for Quasinormal Modes
In this work we discuss charged rotating black holes in
that degenerate to extremal black holes with zero entropy. These black holes
have scaling properties between charge and angular momentum similar to those of
Fermi surface operators in a subsector of SYM. We add a
massless uncharged scalar to the five dimensional supergravity theory, such
that it still forms a consistent truncation of the type IIB ten dimensional
supergravity and analyze its quasinormal modes. Separating the equation of
motion to a radial and angular part, we proceed to solve the radial equation
using the asymptotic matching expansion method applied to a Heun equation with
two nearby singularities. We use the continued fraction method for the angular
Heun equation and obtain numerical results for the quasinormal modes. In the
case of the supersymmetric black hole we present some analytic results for the
decay rates of the scalar perturbations. The spectrum of quasinormal modes
obtained is similar to that of a chiral 1+1 CFT, which is consistent with the
conjectured field-theoretic dual. In addition, some of the modes can be found
analytically.Comment: 41 pages, 1 figure, LaTeX; v2: typos corrected, references adde
Magnetic Catalysis and Quantum Hall Ferromagnetism in Weakly Coupled Graphene
We study the realization in a model of graphene of the phenomenon whereby the
tendency of gauge-field mediated interactions to break chiral symmetry
spontaneously is greatly enhanced in an external magnetic field. We prove that,
in the weak coupling limit, and where the electron-electron interaction
satisfies certain mild conditions, the ground state of charge neutral graphene
in an external magnetic field is a quantum Hall ferromagnet which spontaneously
breaks the emergent U(4) symmetry to U(2)XU(2).
We argue that, due to a residual CP symmetry, the quantum Hall ferromagnet
order parameter is given exactly by the leading order in perturbation theory.
On the other hand, the chiral condensate which is the order parameter for
chiral symmetry breaking generically obtains contributions at all orders. We
compute the leading correction to the chiral condensate. We argue that the
ensuing fermion spectrum resembles that of massive fermions with a vanishing
U(4)-valued chemical potential. We discuss the realization of parity and charge
conjugation symmetries and argue that, in the context of our model, the charge
neutral quantum Hall state in graphene is a bulk insulator, with vanishing
longitudinal conductivity due to a charge gap and Hall conductivity vanishing
due to a residual discrete particle-hole symmetry.Comment: 35 page
Holographic c-theorems in arbitrary dimensions
We re-examine holographic versions of the c-theorem and entanglement entropy
in the context of higher curvature gravity and the AdS/CFT correspondence. We
select the gravity theories by tuning the gravitational couplings to eliminate
non-unitary operators in the boundary theory and demonstrate that all of these
theories obey a holographic c-theorem. In cases where the dual CFT is
even-dimensional, we show that the quantity that flows is the central charge
associated with the A-type trace anomaly. Here, unlike in conventional
holographic constructions with Einstein gravity, we are able to distinguish
this quantity from other central charges or the leading coefficient in the
entropy density of a thermal bath. In general, we are also able to identify
this quantity with the coefficient of a universal contribution to the
entanglement entropy in a particular construction. Our results suggest that
these coefficients appearing in entanglement entropy play the role of central
charges in odd-dimensional CFT's. We conjecture a new c-theorem on the space of
odd-dimensional field theories, which extends Cardy's proposal for even
dimensions. Beyond holography, we were able to show that for any
even-dimensional CFT, the universal coefficient appearing the entanglement
entropy which we calculate is precisely the A-type central charge.Comment: 62 pages, 4 figures, few typo's correcte
MHC class I A region diversity and polymorphism in macaque species
The HLA-A locus represents a single copy gene that displays abundant allelic polymorphism in the human population, whereas, in contrast, a nonhuman primate species such as the rhesus macaque (Macaca mulatta) possesses multiple HLA-A-like (Mamu-A) genes, which parade varying degrees of polymorphism. The number and combination of transcribed Mamu-A genes present per chromosome display diversity in a population of Indian animals. At present, it is not clearly understood whether these different A region configurations are evolutionarily stable entities. To shed light on this issue, rhesus macaques from a Chinese population and a panel of cynomolgus monkeys (Macaca fascicularis) were screened for various A region-linked variations. Comparisons demonstrated that most A region configurations are old entities predating macaque speciation, whereas most allelic variation (>95%) is of more recent origin. The latter situation contrasts the observations of the major histocompatibility complex class II genes in rhesus and cynomolgus macaques, which share a high number of identical alleles (>30%) as defined by exon 2 sequencing
Management of Solid-pseudopapillary Neoplasms of the Pancreas: a Comparison with Standard Pancreatic Neoplasms
BACKGROUND: Solid-pseudopapillary neoplasms (SPNs) of the pancreas are increasingly diagnosed, but the exact surgical management in terms of extent of the resection is not well defined. MATERIALS AND METHODS: Patients operated on in our hospital between January 1993 and March 2005 formed the study groups. RESULTS: From 659 consecutive resections for pancreatic neoplasms, 12 female patients (1.8%) with a median age of 21 years who underwent resection for (SPN) are compared with the remaining 647 pancreatic resection patients. Jaundice (SPN 0 versus PR 73%, p < 0.001) and weight loss (SPN 0 versus PR 49%, p = 0.001) occurred significantly less often. Neoplasms were distributed equally among the pancreatic head (SPN 5 out of 12 patients versus PR 88%, p < 0.001) and corpus/tail (SPN 6 out of 12 patients versus PR 8%, p < 0.001). The operative time was significantly shorter (SPN 233 min versus PR 280 min, p = 0.012), and there were significantly fewer complications (SPN 1 of 12 patients versus PR 48%, p = 0.007). The mortality was not different (SPN 0 versus PR 1.6%, p = 1.000), and the hospital stay was significantly shorter (SPN 9 days versus PR 15 days, p = 0.012). The median size of the neoplasms was significantly larger (SPN 6.9 cm versus PR 2.5 cm). The median number of lymph nodes harvested was significantly fewer (SPN 1 versus PR 6, p = 0.001), and lymph node metastases occurred significantly less often (SPN 0 versus PR 64%, p < 0.001). The 5-year survival of SPN patients was 100% and is significantly better compared with survival of patients with pancreatic adenocarcinoma (12%, p < 0.001) and ampulla of Vater adenocarcinoma (22%, p = 0.005). CONCLUSIONS: Patients with solid-pseudopapillary neoplasms of the pancreas present differently and the course of the disease is more benign. These patients can be adequately managed by pylorus-preserving pancreatoduodenectomy or spleen-preserving distal pancreatectomy with excellent early and long-term result
Abordagem da artroplastia total do joelho no Brasil: estudo transversal
CONTEXT AND OBJECTIVE: Total knee arthroplasty (TKA) has evolved particularly since the 1970s, with improvements in implants and surgical instruments, and has thus become an effective intervention for treating knee arthrosis. Many studies have presented rates of satisfactory clinical and radiological results greater than 90%, from follow-ups of over ten years. Nevertheless, despite scientific evidence showing the efficacy of TKA, the approaches taken present controversies in certain respects. The objective of this study was to evaluate how the Brazilian orthopedists deal with TKA, with investigation of the main aspects of this procedure. DESIGN AND SETTING: Cross-sectional survey conducted during the 39th Brazilian Congress of Orthopedics and Traumatology, in São Paulo, Brazil, in November 2007. METHODS: We applied a questionnaire to orthopedists registered at the congress. The questionnaire was randomly distributed and participation was voluntary; 858 completed questionnaires were included in the analysis. RESULTS: Most of the Brazilian orthopedists were members of SBOT and worked in the southeastern region. They used imported cemented implants through an anterior access route centered on the patella, with replacement of the joint surface of the patella and preservation of the posterior cruciate ligament. They did not have experience with simultaneous bilateral TKA. Postoperatively, they used antibiotics and suction drains for 48 hours. There was no consensus regarding prophylaxis for venous thromboembolism or the frequency of the main complications. CONCLUSION: The majority of Brazilian orthopedists work in the southeastern region of the country and agree about the main aspects of the approaches towards TKA.CONTEXTO E OBJETIVO: A artroplastia total do joelho (ATJ) evoluiu sobremaneira desde os anos 70, com melhora dos implantes e do instrumental cirúrgico, tornando-se uma intervenção efetiva para o tratamento da artrose do joelho. Muitos estudos apresentam resultados clínicos e radiológicos satisfatórios superiores a 90% no acompanhamento acima de 10 anos. Apesar das evidências científicas sobre sua eficácia da ATJ, a sua abordagem apresenta controvérsias em alguns aspectos. O objetivo do estudo foi avaliar como o ortopedista brasileiro aborda a ATJ e os principais aspectos técnicos na realização deste procedimento. TIPO DE ESTUDO E LOCAL: Estudo transversal, realizado durante o 39º Congresso Brasileiro de Ortopedia e Traumatologia em São Paulo, Brasil, em novembro de 2007. MÉTODOS: Aplicamos um questionário aos ortopedistas inscritos no congresso. A distribuição foi aleatória com adesão voluntária. Foram incluídos 858 questionários para análise. RESULTADOS: A maioria dos Ortopedistas Brasileiros são membros da SBOT e atua na região sudeste. Usam o implante importado, cimentado, por via de acesso anterior centrada na patela, com substituição da superfície articular da patela e preservação do ligamento cruzado posterior e não tem experiência com a artroplastia total bilateral simultânea. No pós-operatório utilizam antibióticos e dreno de sucção por 48 horas. Não houve consenso quanto à profilaxia para tromboembolismo venoso e frequência das principais complicações. CONCLUSÃO: A maioria dos ortopedistas brasileiros trabalha na região sudeste e concorda quanto aos principais aspectos da abordagem da ATJ.Universidade Federal de São Paulo (UNIFESP) Department of Orthopedics and TraumatologyUniversidade Federal de São Paulo (UNIFESP) Department of Orthopedics and Traumatology Orthopedist and Head of the Knee GroupUNIFESP, Department of Orthopedics and TraumatologyUNIFESP, Department of Orthopedics and Traumatology Orthopedist and Head of the Knee GroupSciEL
Assessing Walking Ability in People with HTLV-1-Associated Myelopathy Using the 10 Meter Timed Walk and the 6 Minute Walk Test
Five to ten million persons, are infected by HTLV-1 of which 3% will develop HTLV-1-associated myelopathy (HAM) a chronic, disabling inflammation of the spinal cord. Walking, a fundamental, complex, multi-functional task is demanding of multiple body systems. Restricted walking ability compromises activity and participation levels in people with HAM (pwHAM). Therapy aims to improve mobility but validated measures are required to assess change.Prospective observational study.To explore walking capacity in pwHAM, walking endurance using the 6 minute walk (6MW), and gait speed, using the timed 10m walk (10mTW).Out-patient setting in an inner London Teaching hospital.Prospective documentation of 10mTW and 6MW distance; walking aid usage and pain scores measured twice, a median of 18 months apart.Data analysis was completed for twenty-six pwHAM, (8♂; 18♀; median age: 57.8 years; median disease duration: 8 years). Median time at baseline to: complete 10m was 17.5 seconds, versus 21.4 seconds at follow up; 23% completed the 6MW compared to 42% at follow up and a median distance of 55m was covered compared to 71m at follow up. Using the 10mTW velocity to predict the 6MW distance, overestimated the distance walked in 6 minutes (p<0.01). Functional decline over time was captured using the functional ambulation categories.The 10mTW velocity underestimated the degree of disability. Gait speed usefully predicts functional domains, shows direction of functional change and comparison with published healthy age matched controls show that these patients have significantly slower gait speeds. The measured differences over 18 months were sufficient to reliably detect change and therefore these assessments can be useful to detect improvement or deterioration within broader disability grades. Walking capacity in pwHAM should be measured using the 10mTW for gait speed and the 6MW for endurance
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