4D Scattering Amplitudes and Asymptotic Symmetries from 2D CFT

We reformulate the scattering amplitudes of 4D flat space gauge theory and gravity in the language of a 2D CFT on the celestial sphere. The resulting CFT structure exhibits an OPE constructed from 4D collinear singularities, as well as infinite-dimensional Kac-Moody and Virasoro algebras encoding the asymptotic symmetries of 4D flat space. We derive these results by recasting 4D dynamics in terms of a convenient foliation of flat space into 3D Euclidean AdS and Lorentzian dS geometries. Tree-level scattering amplitudes take the form of Witten diagrams for a continuum of (A)dS modes, which are in turn equivalent to CFT correlators via the (A)dS/CFT dictionary. The Ward identities for the 2D conserved currents are dual to 4D soft theorems, while the bulk-boundary propagators of massless (A)dS modes are superpositions of the leading and subleading Weinberg soft factors of gauge theory and gravity. In general, the massless (A)dS modes are 3D Chern-Simons gauge fields describing the soft, single helicity sectors of 4D gauge theory and gravity. Consistent with the topological nature of Chern-Simons theory, Aharonov-Bohm effects record the "tracks" of hard particles in the soft radiation, leading to a simple characterization of gauge and gravitational memories. Soft particle exchanges between hard processes define the Kac-Moody level and Virasoro central charge, which are thereby related to the 4D gauge coupling and gravitational strength in units of an infrared cutoff. Finally, we discuss a toy model for black hole horizons via a restriction to the Rindler region.Comment: 66 pages, 8 figures; v2: version to appear in JHE

Cultural competency in the delivery of health services for Indigenous people

Aim and objectives This review aims to examine available evidence on cultural competence in health care settings to identify key approaches and strategies that can contribute to improving the development and implementation of Indigenous health services and programs. The objectives are to: 1. define cultural competency –– we consider the significance of cultural competence and how it has been defined in international and local literature, including the use of similar terms and meanings 2. report on the quantity, nature and quality of available evidence –– we look at available evidence on cultural competency in Australia, New Zealand, Canada and the United States, including how cultural competence has been measured, and assess the quality of the evidence against basic methodological criteria 3. identify approaches and strategies that are effective in improving cultural competency among health services staff 4. examine the relationship between cultural competency and health outcomes 5. develop an evidence-informed conceptual framework of cultural competency

How and when health-care practitioners in Aboriginal Community Controlled Health Services deliver alcohol screening and brief intervention, and why they don’t: A qualitative study

Introduction. Indigenous Australians experience a disproportionately high burden of alcohol-related harm.Alcohol screening and brief intervention (SBI) offers the potential to reduce this harm if barriers to its delivery in Aboriginal Community Controlled Health Services (ACCHSs) can be optimally targeted. Aims. Examine health-care practitioners’ perceptions of, and practices in, alcohol SBI in ACCHSs. Methods. Semi-structured group interviews with 37 purposively selected health staff across five ACCHSs. Results. Alcohol screening independent of standard health assessments was generally selective.The provision of brief intervention was dependent upon factors related to the patient. Four key factors underlying health-care practitioners’ perceptions of alcohol SBI were prominent: outcome expectancy; role congruence; utilisation of clinical systems and processes; and options for alcohol referral. Discussion. The influence of outcome expectancy and role congruence on health-care practitioners’ alcohol SBI practices has been identified previously, as has to a lesser extent, their less than optimal use of clinical systems and processes. The influence of options for alcohol referral on health-care practitioners’ willingness to deliver alcohol SBI primarily related to their misunderstanding of alcohol SBI and the lack of culturally appropriate alcohol referral options for their patients. Conclusion. An intervention combining interactive, supportive and reinforcing evidencebased dissemination strategies is most likely required to enhance health-care practitioners’ knowledge and skills in alcohol SBI delivery, positively orientate them to their role in its delivery, and facilitate integration of evidence-based alcohol SBI into routine clinical processes and locally available systems. [Clifford A, Shakeshaft A, Deans C. How and when health-care practitioners in Aboriginal Community Controlled Health Services deliver alcohol screening and brief intervention, and why they don’t: A qualitative study

A bibliometric review of drug and alcohol research focused on Indigenous peoples of Australia, New Zealand, Canada and the United States

Indigenous peoples of Australia, New Zealand, Canada and the United States experience a disproportionately high burden of harms from substance misuse. Research is therefore required to improve our understanding of substance use in Indigenous populations and provide evidence on strategies effective for reducing harmful use.A search of 13 electronic databases for peer-reviewed articles published between 1993 and 2014 focusing on substance use and Indigenous peoples of Australia, New Zealand, Canada and the United States. Relevant abstracts were classified as data or non-data based research. Data-based studies were further classified as measurement, descriptive or intervention and their trends examined by country and drug type. Intervention studies were classified by type and their evaluation designs classified using the Cochrane Effective Practice and Organisation of Care (EPOC) data collection checklist.There was a statistically significant increase from 1993 to 2014 in the percentage of total publications that were data-based (P\ua

Relative hyperbolicity and similar properties of one-generator one-relator relative presentations with powered unimodular relator

A group obtained from a nontrivial group by adding one generator and one relator which is a proper power of a word in which the exponent-sum of the additional generator is one contains the free square of the initial group and almost always (with one obvious exception) contains a non-abelian free subgroup. If the initial group is involution-free or the relator is at least third power, then the obtained group is SQ-universal and relatively hyperbolic with respect to the initial group.Comment: 11 pages. A Russian version of this paper is at http://mech.math.msu.su/department/algebra/staff/klyachko/papers.htm V3: revised following referee's comment

Computational models as predictors of HIV treatment outcomes for the Phidisa cohort in South Africa

Background: Selecting the optimal combination of HIV drugs for an individual in resourcelimited settings is challenging because of the limited availability of drugs and genotyping.Objective: The evaluation as a potential treatment support tool of computational models that predict response to therapy without a genotype, using cases from the Phidisa cohort in South Africa.Methods: Cases from Phidisa of treatment change following failure were identified that had the following data available: baseline CD4 count and viral load, details of failing and previous antiretroviral drugs, drugs in new regimen and time to follow-up. The HIV Resistance Response Database Initiative’s (RDI’s) models used these data to predict the probability of a viral load < 50 copies/mL at follow-up. The models were also used to identify effective alternative combinations of three locally available drugs.Results: The models achieved accuracy (area under the receiver–operator  characteristic curve) of 0.72 when predicting response to therapy, which is less accurate than for an independent global test set (0.80) but at least comparable to that of genotyping with rules-based interpretation. The models were able to identify alternative locally available three-drug regimens that were predicted to be effective in 69% of all cases and 62% of those whose new treatment failed in the clinic.Conclusion: The predictive accuracy of the models for these South African patients together with the results of previous studies suggest that the RDI’s models have the potential to optimise treatment selection and reduce virological failure in different patient populations, without the use of a genotype

Recommendations for lung cancer screening in Southern Africa

Lung cancer remains the leading cause of cancer-related deaths in southern Africa. Early trials of chest radiograph-based screening in males at high risk for lung cancer found no mortality benefit of a radiograph alone, or a radiograph plus sputum cytology screening strategy. Large prospective studies, including the National Lung Screening Trial, have shown an all-cause mortality benefit when lowdose computed tomography (LDCT) was used as a screening modality in patients that are at high risk of developing lung cancer. The South African Thoracic Society, based on these findings, and those from several international guidelines, recommend that annual LDCT should be offered to patients between 55–74 years of age who are current or former smokers (having quit within the preceding 15 years), with at least a 30-pack year smoking history and with no history of lung cancer. Patients should be in general good health, fit for surgery, and willing to undergo further investigations if deemed necessary. Given the high local prevalence of tuberculosis (TB) infection and post-TB lung disease, which can radiographically mimic lung cancer, a conservative threshold (nodule size ≥6 mm) should be used to determine whether the baseline LDCT screen is positive (thus nodules <6 mm require no action until the next annual screen). If a non-calcified, solid or partly solid nodule is ≥6 mm, but <10 mm with no malignant features (e.g., distinct spiculated margins), the LDCT should be repeated in 6 months. If a solid nodule or the largest component of a non-solid nodule is ≥10 or ≥6 mm and enlarging or with additional malignant features present, definitive action to exclude lung cancer is warranted. Patients should be screened annually until 15 years have elapsed from date of smoking cessation, they turn 80, become unfit for a curative operation or significant changes are observed.K Dheda is supported by the South African MRC (RFA-EMU-02-2017) and the EDCTP (TMA- 2015SF-1043 & TMA-1051-TESAII).http://jtd.amegroups.comam2020Cardiolog

Radar Sounding of the Medusae Fossae Formation Mars: Equatorial Ice or Dry, Low-Density Deposits?

The equatorial Medusae Fossae Formation (MFF) is enigmatic and perhaps among the youngest geologic deposits on Mars. They are thought to be composed of volcanic ash, eolian sediments, or an ice-rich material analogous to polar layered deposits. The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument aboard the Mars Express Spacecraft has detected nadir echoes offset in time-delay from the surface return in orbits over MFF material. These echoes are interpreted to be from the subsurface interface between the MFF material and the underlying terrain. The delay time between the MFF surface and subsurface echoes is consistent with massive deposits emplaced on generally planar lowlands materials with a real dielectric constant of ∼2.9 ± 0.4. The real dielectric constant and the estimated dielectric losses are consistent with a substantial component of water ice. However, an anomalously low-density, ice-poor material cannot be ruled out. If ice-rich, the MFF must have a higher percentage of dust and sand than polar layered deposits. The volume of water in an ice-rich MFF deposit would be comparable to that of the south polar layered deposits

Aesthetics of self-scaling: parallaxed transregionalism and Kutluğ Ataman's art practice

This article examines relations of ethnography, contemporary art-practice, globalisation and scalar geopolitics with particular reference to Kutluğ Ataman’s artworks. Having been shortlisted for the Turner Prize at the Tate and awarded the prestigious international Carnegie Prize in 2004 with his forty-screen video installation Küba (2004), Ataman became an extremely well-known, globally acclaimed artist and filmmaker. Self-conscious of their global travel and critically attentive to the contemporary ethnographic turn in the visual arts scene, Ataman’s video-works perform a conscientious failure of representing cultural alterity as indigeneity. Concentrating on the artist’s engagement with ethnography, this article contains three main parts. Analyses of the selection of videos in each part will give an account of different scalar aspects of Ataman’s artworks. It will first revisit a previous study (Çakirlar 2011) on the artist’s earlier work of video-portraits including Never My Soul! (2002) and Women Who Wear Wigs (1999). A detailed discussion of Küba follows, which may be taken as the ‘hinge - work’ in Ataman’s oeuvre that marks a scalar transition in his critical focus - from body and identity to community and geopolitics. The discussion will then move to a brief analysis of the series Mesopotamian Dramaturgies, including the screen-based sculptures Dome (2009), Column (2009), Frame (2009), English as a Second Language (2009), and The Complete Works of William Shakespeare (2009). Rather than addressing scale as a differential concept, this article aims to demonstrate the ways in which Ataman’s art-practice produces self-scaling, self-regioning subjects that unsettle the hierarchical constructions of scale and facilitates a critique of the scalar normativity within the global art world’s regionalisms and internationalisms

Prefacing unexplored archives from Central Andean surface-to-bedrock ice cores through a multifaceted investigation of regional firn and ice core glaciochemistry.

Shallow firn cores, in addition to a near-basal ice core, were recovered in 2018 from the Quelccaya ice cap (5470 m a.s.l) in the Cordillera Vilcanota, Peru, and in 2017 from the Nevado Illimani glacier (6350 m a.s.l) in the Cordillera Real, Bolivia. The two sites are ~450 km apart. Despite meltwater percolation resulting from warming, particle-based trace element records (e.g. Fe, Mg, K) in the Quelccaya and Illimani shallow cores retain well-preserved signals. The firn core chronologies, established independently by annual layer counting, show a convincing overlap indicating the two records contain comparable signals and therefore capture similar regional scale climatology. Trace element records at a ~1?4 cm resolution provide past records of anthropogenic emissions, dust sources, volcanic emissions, evaporite salts and marine-sourced air masses. Using novel ultra-high-resolution (120 ?m) laser technology, we identify annual layer thicknesses ranging from 0.3 to 0.8 cm in a section of 2000-year-old radiocarbon-dated near-basal ice which compared to the previous annual layer estimates suggests that Quelccaya ice cores drilled to bedrock may be older than previously suggested by depth-age models. With the information collected from this study in combination with past studies, we emphasize the importance of collecting new surface-to-bedrock ice cores from at least the Quelccaya ice cap, in particular, due to its projected disappearance as soon as the 2050s