973 research outputs found
Maximal supergravity in D=10: forms, Borcherds algebras and superspace cohomology
We give a very simple derivation of the forms of supergravity from
supersymmetry and SL(2,\bbR) (for IIB). Using superspace cohomology we show
that, if the Bianchi identities for the physical fields are satisfied, the
(consistent) Bianchi identities for all of the higher-rank forms must be
identically satisfied, and that there are no possible gauge-trivial Bianchi
identities () except for exact eleven-forms. We also show that the
degrees of the forms can be extended beyond the spacetime limit, and that the
representations they fall into agree with those predicted from Borcherds
algebras. In IIA there are even-rank RR forms, including a non-zero
twelve-form, while in IIB there are non-trivial Bianchi identities for
thirteen-forms even though these forms are identically zero in supergravity. It
is speculated that these higher-rank forms could be non-zero when higher-order
string corrections are included.Comment: 15 pages. Published version. Some clarification of the tex
Towards Field Theory Amplitudes From the Cohomology of Pure Spinor Superspace
A simple BRST-closed expression for the color-ordered super-Yang-Mills
5-point amplitude at tree-level is proposed in pure spinor superspace and shown
to be BRST-equivalent to the field theory limit of the open superstring 5-pt
amplitude. It is manifestly cyclic invariant and each one of its five terms can
be associated to the five Feynman diagrams which use only cubic vertices. Its
form also suggests an empirical method to find superspace expressions in the
cohomology of the pure spinor BRST operator for higher-point amplitudes based
on their kinematic pole structure. Using this method, Ansaetze for the 6- and
7-point 10D super-Yang-Mills amplitudes which map to their 14 and 42
color-ordered diagrams are conjectured and their 6- and 7-gluon expansions are
explicitly computed.Comment: 14 pages, harvmac, v4: trivial edits in the text to comply with JHEP
refere
Medical Workforce Issues in Australia: Tomorrow's Doctors - Too Few, Too Far
The Australian medical workforce, like those of most developed countries, is increasingly feminised and exposed to the global market for doctors. Demand for healthcare services is increasing in the Australian community. Concern in relation to doctor shortages is increasing, particularly in rural areas. There should be greater flexibility for entry of highly-trained overseas doctors. There is an urgent need to increase medical school student intake. Issues of workforce practice, including task substitution, should be explored
Explicit BCJ Numerators from Pure Spinors
We derive local kinematic numerators for gauge theory tree amplitudes which
manifestly satisfy Jacobi identities analogous to color factors. They naturally
emerge from the low energy limit of superstring amplitudes computed with the
pure spinor formalism. The manifestation of the color--kinematics duality is a
consequence of the superstring computation involving no more than (n-2)!
kinematic factors for the full color dressed n-point amplitude. The bosonic
part of these results describe gluon scattering independent on the number of
supersymmetries and captures any N^kMHV helicity configuration after
dimensional reduction to D=4 dimensions.Comment: 32 pages, harvma
Simplified form of tinnitus retraining therapy in adults: a retrospective study.
BACKGROUND: Since the first description of tinnitus retraining therapy (TRT), clinicians have modified and customised the method of TRT in order to suit their practice and their patients. A simplified form of TRT is used at Ealing Primary Care Trust Audiology Department. Simplified TRT is different from TRT in the type and (shorter) duration of the counseling but is similar to TRT in the application of sound therapy except for patients exhibiting tinnitus with no hearing loss and no decreased sound tolerance (wearable sound generators were not mandatory or recommended here, whereas they are for TRT). The main goal of this retrospective study was to assess the efficacy of simplified TRT. METHODS: Data were collected from a series of 42 consecutive patients who underwent simplified TRT for a period of 3 to 23 months. Perceived tinnitus handicap was measured by the Tinnitus Handicap Inventory (THI) and perceived tinnitus loudness, annoyance and the effect of tinnitus on life were assessed through the Visual Analog Scale (VAS). RESULTS: The mean THI and VAS scores were significantly decreased after 3 to 23 months of treatment. The mean decline of the THI score was 45 (SD = 22) and the difference between pre- and post-treatment scores was statistically significant. The mean decline of the VAS scores was 1.6 (SD = 2.1) for tinnitus loudness, 3.6 (SD = 2.6) for annoyance, and 3.9 (SD = 2.3) for effect on life. The differences between pre- and post-treatment VAS scores were statistically significant for tinnitus loudness, annoyance, and effect on life. The decline of THI scores was not significantly correlated with age and duration of tinnitus. CONCLUSION: The results suggest that benefit may be obtained from a substantially simplified form of TRT
Simplified form of tinnitus retraining therapy in adults: a retrospective study
BACKGROUND: Since the first description of tinnitus retraining therapy (TRT), clinicians have modified and customised the method of TRT in order to suit their practice and their patients. A simplified form of TRT is used at Ealing Primary Care Trust Audiology Department. Simplified TRT is different from TRT in the type and (shorter) duration of the counseling but is similar to TRT in the application of sound therapy except for patients exhibiting tinnitus with no hearing loss and no decreased sound tolerance (wearable sound generators were not mandatory or recommended here, whereas they are for TRT). The main goal of this retrospective study was to assess the efficacy of simplified TRT. METHODS: Data were collected from a series of 42 consecutive patients who underwent simplified TRT for a period of 3 to 23 months. Perceived tinnitus handicap was measured by the Tinnitus Handicap Inventory (THI) and perceived tinnitus loudness, annoyance and the effect of tinnitus on life were assessed through the Visual Analog Scale (VAS). RESULTS: The mean THI and VAS scores were significantly decreased after 3 to 23 months of treatment. The mean decline of the THI score was 45 (SD = 22) and the difference between pre- and post-treatment scores was statistically significant. The mean decline of the VAS scores was 1.6 (SD = 2.1) for tinnitus loudness, 3.6 (SD = 2.6) for annoyance, and 3.9 (SD = 2.3) for effect on life. The differences between pre- and post-treatment VAS scores were statistically significant for tinnitus loudness, annoyance, and effect on life. The decline of THI scores was not significantly correlated with age and duration of tinnitus. CONCLUSION: The results suggest that benefit may be obtained from a substantially simplified form of TRT
Expression of therapeutic misconception amongst Egyptians: a qualitative pilot study
<p>Abstract</p> <p>Background</p> <p>Studies have shown that research participants fail to appreciate the difference between research and medical care, labeling such phenomenon as a "therapeutic misconception" (TM). Since research activity involving human participants is increasing in the Middle East, qualitative research investigating aspects of TM is warranted. Our objective was to assess for the existence of therapeutic misconception amongst Egyptians.</p> <p>Methods</p> <p><it>Study Tool: </it>We developed a semi-structured interview guide to elicit the knowledge, attitudes, and perspectives of Egyptians regarding medical research.</p> <p><it>Setting: </it>We recruited individuals from the outpatient settings (public and private) at Ain Shams University in Cairo, Egypt.</p> <p><it>Analysis: </it>Interviews were taped, transcribed, and translated. We analyzed the content of the transcribed text to identify the presence of a TM, defined in one of two ways: TM<sub>1 </sub>= inaccurate beliefs about how individualized care can be compromised by the procedures in the research and TM<sub>2 </sub>= inaccurate appraisal of benefit obtained from the research study.</p> <p>Results</p> <p>Our findings showed that a majority of participants (11/15) expressed inaccurate beliefs regarding the degree with which individualized care will be maintained in the research setting (TM<sub>1</sub>) and a smaller number of participants (5/15) manifested an unreasonable belief in the likelihood of benefits to be obtained from a research study (TM<sub>2</sub>). A total of 12 of the 15 participants were judged to have expressed a TM on either one of these bases.</p> <p>Conclusion</p> <p>The presence of TM is not uncommon amongst Egyptian individuals. We recommend further qualitative studies investigating aspects of TM involving a larger sample size distinguished by different types of illnesses and socio-economic variables, as well as those who have and have not participated in clinical research.</p
Predictors of mortality in HIV-infected patients starting antiretroviral therapy in a rural hospital in Tanzania
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Studies of antiretroviral therapy (ART) programs in Africa have shown high initial mortality. Factors contributing to this high mortality are poorly described. The aim of the present study was to assess mortality and to identify predictors of mortality in HIV-infected patients starting ART in a rural hospital in Tanzania. This was a cohort study of 320 treatment-naĂŻve adults who started ART between October 2003 and November 2006. Reliable CD4 cell counts were not available, thus ART initiation was based on clinical criteria in accordance with WHO and Tanzanian guidelines. Kaplan-Meier models were used to estimate mortality and Cox proportional hazards models to identify predictors of mortality. Patients were followed for a median of 10.9 months (IQR 2.9-19.5). Overall, 95 patients died, among whom 59 died within 3 months of starting ART. Estimated mortality was 19.2, 29.0 and 40.7% at 3, 12 and 36 months, respectively. Independent predictors of mortality were severe anemia (hemoglobin <8 g/dL; adjusted hazard ratio [AHR] 9.20; 95% CI 2.05-41.3), moderate anemia (hemoglobin 8-9.9 g/dL; AHR 7.50; 95% CI 1.77-31.9), thrombocytopenia (platelet count <150 x 109/L; AHR 2.30; 95% CI 1.33-3.99) and severe malnutrition (body mass index <16 kg/m2; AHR 2.12; 95% CI 1.06-4.24). Estimated one year mortality was 55.2% in patients with severe anemia, compared to 3.7% in patients without anemia (P < 0.001). Mortality was found to be high, with the majority of deaths occurring within 3 months of starting ART. Anemia, thrombocytopenia and severe malnutrition were strong independent predictors of mortality. A prognostic model based on hemoglobin level appears to be a useful tool for initial risk assessment in resource-limited settings.\u
Endothelins are vascular-derived axonal guidance cues for developing sympathetic neurons
During development, sympathetic neurons extend axons along a myriad of distinct trajectories, often consisting of arteries, to innervate one of a large variety of distinct final target tissues. Whether or not subsets of neurons within complex sympathetic ganglia are predetermined to innervate select end-organs is unknown. Here we demonstrate in mouse embryos that the endothelin family member Edn3 (ref. 1), acting through the endothelin receptor EdnrA (refs 2, 3), directs extension of axons of a subset of sympathetic neurons from the superior cervical ganglion to a preferred intermediate target, the external carotid artery, which serves as the gateway to select targets, including the salivary glands. These findings establish a previously unknown mechanism of axonal pathfinding involving vascular-derived endothelins, and have broad implications for endothelins as general mediators of axonal growth and guidance in the developing nervous system. Moreover, they suggest a model in which newborn sympathetic neurons distinguish and choose between distinct vascular trajectories to innervate their appropriate end organs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62906/1/nature06859.pd
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