1,312 research outputs found
Non-singlet Baryons in Less Supersymmetric Backgrounds
We analyze the holographic description of non-singlet baryons in various
backgrounds with reduced supersymmetries and/or confinement. We show that they
exist in all AdS_5xY_5 backgrounds with Y_5 an Einstein manifold bearing five
form flux, for a number of quarks 5N/8< k< N, independently on the
supersymmetries preserved. This result still holds for gamma_i deformations. In
the confining Maldacena-Nunez background non-singlet baryons also exist,
although in this case the interval for the number of quarks is reduced as
compared to the conformal case. We generalize these configurations to include a
non-vanishing magnetic flux such that a complementary microscopical description
can be given in terms of lower dimensional branes expanding into fuzzy baryons.
This description is a first step towards exploring the finite 't Hooft coupling
region.Comment: 36 Pages, 1 figure, Latex, v2: few minor changes, JHEP versio
A subset of non-small cell lung cancer patients treated with pemetrexed show 18f-fluorothymidine ‘flare’ on positron emission tomography
Thymidylate synthase (TS) remains a major target for cancer therapy. TS inhibition elicits increases in DNA salvage pathway activity, detected as a transient compensatory “flare” in 3′-deoxy-3′-[18F]fluorothymidine positron emission tomography (18F-FLT PET). We determined the magnitude of the 18F-FLT flare in non-small cell lung cancer (NSCLC) patients treated with the antifolate pemetrexed in relation to clinical outcome. Method: Twenty-one patients with advanced/metastatic non-small cell lung cancer (NSCLC) scheduled to receive palliative pemetrexed ± platinum-based chemotherapy underwent 18F-FLT PET at baseline and 4 h after initiating single-agent pemetrexed. Plasma deoxyuridine (dUrd) levels and thymidine kinase 1 (TK1) activity were measured before each scan. Patients were then treated with the combination therapy. The 18F-FLT PET variables were compared to RECIST 1.1 and overall survival (OS). Results: Nineteen patients had evaluable PET scans at both time points. A total of 32% (6/19) of patients showed 18F-FLT flares (>20% change in SUVmax-wsum). At the lesion level, only one patient had an FLT flare in all the lesions above (test–retest borders). The remaining had varied uptake. An 18F-FLT flare occurred in all lesions in 1 patient, while another patient had an 18F-FLT reduction in all lesions; 17 patients showed varied lesion uptake. All patients showed global TS inhibition reflected in plasma dUrd levels (p < 0.001) and 18F-FLT flares of TS-responsive normal tissues including small bowel and bone marrow (p = 0.004 each). Notably, 83% (5/6) of patients who exhibited 18F-FLT flares were also RECIST responders with a median OS of 31 m, unlike patients who did not exhibit 18F-FLT flares (15 m). Baseline plasma TK1 was prognostic of survival but its activity remained unchanged following treatment. Conclusions: The better radiological response and longer survival observed in patients with an 18F-FLT flare suggest the efficacy of the tracer as an indicator of the early therapeutic response to pemetrexed in NSCLC
Fermionic T-duality in the pp-wave limit
AdS5 X S5 and its pp-wave limit are self-dual under transformations involving
eight fermionic T-dualities, a property which accounts for symmetries seen in
scattering amplitudes in N=4 super-Yang-Mills. Despite strong evidence for
similar symmetries in the amplitudes of three-dimensional N=6 ABJM theory, a
corresponding self-duality in the dual geometry AdS4 X CP3 currently eludes us.
Here, working with the type IIA pp-wave limit of AdS4 X CP3 preserving twenty
four supercharges, we show that the pp-wave is self-dual with respect to eight
commuting fermionic T-dualities and not the six expected. In addition, we show
the same symmetry can be found in a superposition pp-wave and a generic pp-wave
with twenty and sixteen unbroken supersymmetries respectively, strongly
suggesting that self-duality under fermionic T-duality may be a symmetry of all
pp-waves.Comment: 21 pages, typos fixe
Self-duality of the D1-D5 near-horizon
We explore fermionic T-duality and self-duality in the geometry AdS3 x S3 x
T4 in type IIB supergravity. We explicitly construct the Killing spinors and
the fermionic T-duality isometries and show that the geometry is self-dual
under a combination of two bosonic AdS3 T-dualities, four fermionic T-dualities
and either two additional T-dualities along T4 or two T-dualities along S3. In
addition, we show that the presence of a B-field acts as an obstacle to
self-duality, a property attributable to S- duality and fermionic T-duality not
commuting. Finally, we argue that fermionic T-duality may be extended to CY2 =
K3, a setting where we cannot explicitly construct the Killing spinors.Comment: 24 pages, references added, changes made to reinforce the point that
S-duality and fermionic T-duality generically do not commute, version
accepted to JHE
Type IIB supergravity solutions with AdS5 from Abelian and non-Abelian T dualities
We present a large class of new backgrounds that are solutions of type IIB
supergravity with a warped AdS factor, non-trivial axion-dilaton,
-field and three-form Ramond-Ramond flux but yet have no five-form flux. We
obtain these solutions and many of their variations by judiciously applying
non-Abelian and Abelian T-dualities, as well as coordinate shifts to
AdS IIB supergravity solutions with . We address a number of issues pertaining to charge quantization in
the context of non-Abelian T-duality. We comment on some properties of the
expected dual super conformal field theories by studying their CFT central
charge holographically. We also use the structure of the supergravity Page
charges, central charges and some probe branes to infer aspects of the dual
super conformal field theories.Comment: 71 pages, one table. v2: References added, some normalizations
corrected, results unchange
Illness perceptions and explanatory models of viral hepatitis B & C among immigrants and refugees: a narrative systematic review.
© 2015 Owiti et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain
Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article,
unless otherwise stated.BACKGROUND: Hepatitis B and C (HBV, HCV) infections are associated with high morbidity and mortality. Many countries with traditionally low prevalence (such as UK) are now planning interventions (screening, vaccination, and treatment) of high-risk immigrants from countries with high prevalence. This review aimed to synthesise the evidence on immigrants' knowledge of HBV and HCV that might influence the uptake of clinical interventions. The review was also used to inform the design and successful delivery of a randomised controlled trial of targeted screening and treatment. METHODS: Five databases (PubMed, CINHAL, SOCIOFILE, PsycINFO & Web of Science) were systematically searched, supplemented by reference tracking, searches of selected journals, and of relevant websites. We aimed to identify qualitative and quantitative studies that investigated knowledge of HBV and HCV among immigrants from high endemic areas to low endemic areas. Evidence, extracted according to a conceptual framework of Kleinman's explanatory model, was subjected to narrative synthesis. We adapted the PEN-3 model to categorise and analyse themes, and recommend strategies for interventions to influence help-seeking behaviour. RESULTS: We identified 51 publications including quantitative (n = 39), qualitative (n = 11), and mixed methods (n = 1) designs. Most of the quantitative studies included small samples and had heterogeneous methods and outcomes. The studies mainly concentrated on hepatitis B and ethnic groups of South East Asian immigrants residing in USA, Canada, and Australia. Many immigrants lacked adequate knowledge of aetiology, symptoms, transmission risk factors, prevention strategies, and treatment, of hepatitis HBV and HCV. Ethnicity, gender, better education, higher income, and English proficiency influenced variations in levels and forms of knowledge. CONCLUSION: Immigrants are vulnerable to HBV and HCV, and risk life-threatening complications from these infections because of poor knowledge and help-seeking behaviour. Primary studies in this area are extremely diverse and of variable quality precluding meta-analysis. Further research is needed outside North America and Australia
Non-Abelian T-duality and consistent truncations in type-II supergravity
For a general class of SO(4) symmetric backgrounds in type II-supergravity,
we show that the action of non-Abelian T-duality can be described via
consistent truncation to seven dimensional theories with seemingly massive
modes. As such, any solution to these theories uplifts to both massive type IIA
and IIB supergravities presenting an invertible map between the two. For
supersymmetric backgrounds, we show that for spinors transforming under SO(4)
the non-Abelian T-duality transformation breaks the original supersymmetry by
half. We use these mappings to generate the non-Abelian T-duals of the
maximally supersymmetric pp-wave, the Lin, Lunin, Maldacena geometries and
spacetimes with Lifshitz symmetry.Comment: 41 pages, references added, published versio
New N =1 supersymmetric AdS 5 backgrounds in type IIA supergravity
We present a family of N=1 supersymmetric backgrounds in type-IIA supergravity and their lifts to eleven-dimensional supergravity. These are of the form AdS5×X5 and are characterised by an SU(2) structure. The internal space, X5, is obtained from the known Sasaki-Einstein manifolds, Yp,q, via an application of non-Abelian T-duality
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