449 research outputs found

    Critical behavior at Mott-Anderson transition: a TMT-DMFT perspective

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    We present a detailed analysis of the critical behavior close to the Mott-Anderson transition. Our findings are based on a combination of numerical and analytical results obtained within the framework of Typical-Medium Theory (TMT-DMFT) - the simplest extension of dynamical mean field theory (DMFT) capable of incorporating Anderson localization effects. By making use of previous scaling studies of Anderson impurity models close to the metal-insulator transition, we solve this problem analytically and reveal the dependence of the critical behavior on the particle-hole symmetry. Our main result is that, for sufficiently strong disorder, the Mott-Anderson transition is characterized by a precisely defined two-fluid behavior, in which only a fraction of the electrons undergo a "site selective" Mott localization; the rest become Anderson-localized quasiparticles.Comment: 4+ pages, 4 figures, v2: minor changes, accepted for publication in Phys. Rev. Let

    Knowledge, attitudes and practices of South Asian immigrants in developed countries regarding oral cancer : an integrative review

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    Background: Oral cancer is a growing problem worldwide, with high incidence rates in South Asian countries. With increasing numbers of South Asian immigrants in developed countries, a possible rise in oral cancer cases is expected given the high prevalence in their source countries and the continued oral cancer risk behaviours of immigrants. The aim of this review is to synthesise existing evidence regarding knowledge, attitudes and practices of South Asian immigrants in developed countries regarding oral cancer. Methods: Five electronic databases were systematically searched to identify original, English language articles focussing on oral cancer risk knowledge, attitudes and practices of South Asian immigrants in developed countries. All studies that met the following inclusion criteria were included: conducted among South Asian immigrants in developed countries; explored at least one study outcome (knowledge or attitudes or practices); used either qualitative, quantitative or mixed methods. No restrictions were placed on the publication date, quality and setting of the study. Results: A total of 16 studies involving 4772 participants were reviewed. These studies were mainly conducted in the USA, UK, Italy and New Zealand between 1994 and 2018. Findings were categorised into themes of oral cancer knowledge, attitudes and practices. General lack of oral cancer risk knowledge (43–76%) among participants was reported. More than 50% people were found engaging in one or more oral cancer risk practices like smoking, betel quid/pan/gutka chewing. Some of the participants perceived betel quid/pan/gutka chewing habit good for their health (12–43.6%). Conclusion: This review has shown that oral cancer risk practices are prevalent among South Asian immigrants who possess limited knowledge and unfavourable attitude in this area. Culturally appropriate targeted interventions and strategies are needed to raise oral cancer awareness among South Asian communities in developed countries

    Perceptions and practices of general practitioners towards oral cancer and emerging risk factors among Indian immigrants in Australia : a qualitative study

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    Background: In Australia, Indian immigrants are one of the fastest-growing communities. Since oral cancer is widespread in India, the indulgence of Indians in customs of areca (betel) nut use in Australia may be linked to the recent rise in oral cancer cases. Since GPs (general practitioners) are primary healthcare providers, it is pivotal to ensure the oral cancer awareness of GPs. This study aimed to explore oral cancer risk-related knowledge, beliefs, and clinical practices of GPs in Australia. Methods: Fourteen semi-structured interviews were conducted with GPs practicing across New South Wales and Victoria. Purposive and snowball sampling were used for recruitment. Data were analysed through a directed content analysis approach. Results: All GPs were knowledgeable of major oral cancer causative factors including tobacco and alcohol, but some had limited understanding about the risks associated with areca nut preparations. Positive attitudes were evident, with all participants acknowledging the importance of oral cancer risk assessment. Most GPs recalled not performing oral cancer routine check-ups. Conclusion: GPs presented good oral cancer knowledge except for emerging risk factors such as areca nut use. Varied beliefs and inconsistent clinical practices relating to oral cancer screening is concerning. Accessible oral cancer training around emerging risk factors may benefit GPs

    Detecting Determinacy in Prolog Programs: 22nd International Conference, ICLP 2006, Seattle, WA, USA, August 17-20, 2006. Proceedings

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    In program development it is useful to know that a call to a Prolog program will not inadvertently leave a choice-point on the stack. Determinacy inference has been proposed for solving this problem yet the analysis was found to be wanting in that it could not infer determinacy conditions for programs that contained cuts or applied certain tests to select a clause. This paper shows how to remedy these serious deficiencies. It also addresses the problem of identifying those predicates which can be rewritten in a more deterministic fashion. To this end, a radically new form of determinacy inference is introduced, which is founded on ideas in ccp, that is capable of reasoning about the way bindings imposed by a rightmost goal can make a leftmost goal deterministic

    Knowledge, attitudes and practices of Indian immigrants in Australia towards oral cancer and their perceived role of general practitioners : a cross-sectional study

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    Oral cancer is highly prevalent in the Indian subcontinent. With the increasing immigration of Indians to Australia, a potential rise in oral cancer cases can be expected if they continue engaging in oral cancer risk practices. Unfortunately, little is known on this topic in the Australian context. This study aimed to generate new insights into this area by examining Indian immigrants’ knowledge, attitudes and practices regarding oral cancer in Australia and their perceived role of general practitioners in raising oral cancer awareness. Exploring these aspects could determine the oral cancer risk behaviours of Indians in Australia along with any contributing factors which could help identify potential preventative strategies. A cross-sectional survey was undertaken of 164 Indians across Australia. Data were analysed using SPSS software with descriptive statistics. Respondents had varying levels of knowledge about oral cancer (mean total score 61%), particularly around risk factors such as alcohol and areca nut use as well as oral cancer-related signs/symptoms. The majority (87.7%) had not received any information about oral cancer in a health care setting but were receptive (71–90%) to general practitioners playing a more active role in this area. Respondents were engaging in positive preventative oral health care though few were currently (6.7%) or previously (14.7%) chewing tobacco preparations. Further research is needed through larger studies to confirm the study findings and inform the development of culturally tailored strategies particularly involving general practitioners, to raise oral cancer awareness and provide early screening for Indian immigrants

    Evidence for a Neutron Star in the non-pulsating massive X-ray binary 4U2206+54

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    We present an analysis of archival RXTE and BeppoSAX data of the X-ray source 4U2206+54 . For the first time, high energy data (> 30 kev) are analyzed for this source. The data are well described by comptonization models (CompTT and BMC) in which seed photons with temperatures between 1.1 kev and 1.5 kev are comptonized by a hot plasma at 50 kev thereby producing a hard tail which extends up to, at least, 100 kev. We offer a new method of identification of neutron star systems using a temperature - luminosity relation. If a given X-ray source is characterized by a low bolometric luminosity and a relatively high color blackbody temperature (>1 kev) it has necessarily to be a neutron star rather than a black hole. From these arguments it is shown that the area of the soft photon source must be small (r ~ 1 km) and that the accretion disk, if present, must be truncated very far from the compact object. Here we report on the possible existence of a cyclotron line around 30 kev. The presence of a neutron star in the system is strongly favored by the available data.Comment: Accepted for publication in A&A. 9 pages, 7 figures. Submitted to journal in November 200

    A look with BeppoSAX at the low-luminosity Galactic X-ray source 4U 2206+54

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    A pointed observation of the low-luminosity galactic source 4U 2206+54 was carried out in November 1998 with BeppoSAX. The light curve of 4U 2206+54 shows erratic variability on a timescale of about 1 hour; neither hardness variations nor time periodicities are detected throughout this 67 ks long observation. Thanks to the wide spectral coverage capabilities of BeppoSAX we could observe the source X-ray continuum over three energy decades, from 0.6 to 60 keV. The spectrum could be equally well fitted either with a blackbody plus Comptonization or with a high energy cutoff power law. No iron emission around 6.5 keV was detected, while a tentative detection of a cyclotron resonant feature in absorption is presented. Comparison of the present BeppoSAX data with the information available in the literature for this source suggests that 4U 2206+54 is a close binary system in which a (possibly magnetized) NS is accreting from the companion star wind.Comment: 9 pages, 5 figures, 2 tables; accepted for publication on Astronomy & Astrophysics, main journal. Final version of the paper including the A&A Language Editor's comment
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