124,849 research outputs found
A postal survey to identify and describe nurse led clinics in genitourinary medicine services across England
No full textSexual health clinics for women led by specialist nurses or senior house officers in a central London GUM service: a randomised controlled trial
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Increasing risk behaviour and high levels of undiagnosed HIV infection in a community sample of homosexual men
No full textObjectives: To estimate changes in sexual behaviour over time. To examine the proportion of undiagnosed HIV infection in a community sample of homosexual men. To explore the relation between HIV status, diagnosis, and sexual behaviour.Methods: Five cross sectional surveys of men attending selected gay community venues in London between 1996 and 2000 (n = 8052). Men were recruited in 45 to 58 social venues ( including bars, clubs, and saunas) across London. Participants self completed an anonymous behavioural questionnaire. In 2000, participants in community venues provided anonymous saliva samples for testing for anti-HIV antibody.Results: The proportion of men having unprotected anal intercourse (UAI) increased significantly each year from 30% in 1996 to 42% in 2000 (p << 0.001). In 2000, 132 of 1206 (10.9%) saliva samples were HIV antibody positive. Of the HIV saliva antibody positive samples, 43/132 (32.5%) were undiagnosed. Around half of both diagnosed and undiagnosed HIV saliva positive men reported UAI in the past year. Of the 83% of men who reported their current perceived HIV status, 4.1% reported an incorrect status. HIV antibody positivity was associated with increasing numbers of UAI partners, and having a sexually transmitted infection (STI) in the past year (OR 2.15).Conclusions: Homosexual men continue to report increasing levels of UAI. HIV prevalence is high in this group, with many infections remaining undiagnosed. The high level of risky behaviour in HIV positive men, regardless of whether they are diagnosed, is of public health concern, in an era when HIV prevalence, antiretroviral resistance, and STI incidence are increasing
A tale of three cities: persisting high HIV prevalence, risk behaviour and undiagnosed infection in community samples of men who have sex with men
No full textObjectives: To examine the geographical variations in HIV prevalence (diagnosed and undiagnosed), use of sexual health services, sexually transmitted infections and sexual behaviour in a community sample of men who have sex with men in three cities in England, specifically London, Brighton and Manchester.Methods: Cross-sectional surveys of men visiting gay community venues in three large cities in England. Men self-completed a questionnaire and provided an anonymous oral fluid sample for HIV antibody testing.Results: HIV prevalence ranged from 8.6% to 13.7% in the three cities. Over one-third of HIV infection remained undiagnosed in all sites despite 69% of HIV-positive men reporting attending a genitourinary medicine clinic in the last year. Similar and high levels of risk behaviour were reported in all three cities. 18% of HIV-negative men and 37% of HIV-positive men reported unprotected anal intercourse with more than one partner in the last year. 20% of negative men and 41% of positive men reported an STI in the last year.Conclusions: Across all cities, despite widespread availability of anti-retroviral treatment and national policy to promote HIV testing, many HIV infections remain undiagnosed. Data from this community sample demonstrate high levels of risk behaviour and STI incidence, especially among those who are HIV positive. Renewed efforts are needed to increase diagnosis and to reduce risk behaviour to stem the continuing transmission of HIV
Study of Ba Core Level Binding Energies in a YBa2Cu3O~7 Thin Film.
No full textA thin film of superconducting YBa2Cu3O~7 (YBCO) system (Tc ~ 89 K) has been studied by x-ray photoelectron spectroscopy (XPS) to investigate the core level electronic structure. The Ba 3d and 4d core level XPS spectra show three binding energy components with the high binding energy component originating from the non-superconducting surface of the system. The role of oxygen ordering/disordering has been discussed to explain the origin of the other two bulk-dependent components. An attempt has been made to resolve some of the discrepancies in the Ba core level spectra reported earlier
High Tc superconducting oxycarbonate thin films grown by laser ablation : Promising new materials
No full textSuperconducting thin films of copper oxycarbonates, with the general composition (CaCuO2)m(Ba2-xAxCuO 2CO3)n (A=Ca,Sr), have been synthesized for the first time using the pulsed laser deposition technique. Via a single target system, i.e. a Ba2Ca3Cu4Ox target, the film exhibits a Tc(onset) of 110K. The m=0 member of the family, Ba2-xAxCuO2CO3, has also been studied. Structures and structural mechanisms are presented
Pulsed laser deposition of Ba(2-x)A(x)CuO(2)CO(3) (A=Ca, Sr) thin films, m=0 member of the series (CaCuO2)(m)(Ba(2-x)A(x)CuO(2)CO(3))(n) (A=Ca, Sr)
No full textCopper oxycarbonate thin films of the (CaCuO2)(m)(Ba(2-x)A(x)CuO(2)CO(3))(n) (A = Ca, Sr) system have been deposited, using the pulsed laser deposition (PLD) technique, on (100) LaAlO3 and (110) NdGaO3 substrates. The m = 0 member of the family, Ba2-xSrxCuO2CO3 (x = 0.1 and x = 0.4) has been deposited in a selective way for the first time on both LaAlO3 and NdGaO3. The best results have been obtained for NdGaO3 substrates, but a double orientation of the film, [001] and [110], is found by transmission electron microscopy (TEM) for x = 0.4. Ba2-xCaxCuO2CO3 (x = 0.2) has also been studied. At a deposition temperature of 620 degrees C, a Ba2CuO2CO3 (B2CC) type structure is stabilized, whereas at 680 degrees C another perovskite is isolated. Attempts to deposit the member (m = 1, n = 1, x = 0) of the family, i.e., Ba2CaCu2O4CO3, on LaAlO3 using a single multiphase sintered ceramic target led to the formation of a B2CC type structure (m = 0) coherently intergrown with CaCu2O3 and Ca2CuO3 extended defects. The structures and structural mechanisms are discussed. No diamagnetic transition was observed in any of these films down to 5 K
Films minces d'oxycarbonates preparees par ablation laser pulsee : du systeme monocible au systeme multicible
No full textThe microstructural study of superconductor thin films with general formula: (CaCuO2)m(Ba2CuO2CO 3)n, grown from a single target, has shown that these films exhibited numerous intergrowth phases. Such films can not be used for precise physical studies. To obtain a regular stacking along a growth direction perpendicular to the substrate a multi-target system has to be used. The preliminary results of this study are presented herein
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