1,767 research outputs found
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
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
One-loop SYM-supergravity relation for five-point amplitudes
We derive a linear relation between the one-loop five-point amplitude of N=8
supergravity and the one-loop five-point subleading-color amplitudes of N=4
supersymmetric Yang-Mills theory.Comment: 17 pages, 2 figures; v2: very minor correction
Office bladder distention with Electromotive Drug Administration (EMDA) is equivalent to distention under General Anesthesia (GA)
BACKGROUND: Bladder distention is commonly used in diagnosis and treatment of interstitial cystitis (IC). Traditionally performed in the operating room under general or spinal anesthesia (GA), it is expensive and associated with short term morbidity. Office bladder distention using electromotive drug administration (EMDA) has been suggested as an alternative that is well tolerated by patients. We report the first comparative findings of patients undergoing both office distention with EMDA and distention in the operating room (OR) with GA. METHODS: This retrospective chart review identified 11 patients participating in two protocols of EMDA bladder distention who also underwent bladder distention under GA either prior to or after the EMDA procedure. RESULTS: The median absolute difference in bladder capacity between GA and EMDA was only 25 cc; the median percent difference was 5%. Cystoscopic findings, while not prospectively compiled, appear to have been similar. CONCLUSION: This study represents the first comparison between distention with EMDA versus GA and confirms the technical feasibility of performing bladder distention in an office setting. The distention capacity achieved in the office was nearly identical to that in the OR and the cystoscopic findings very similar. Further investigation into the comparative morbidity, cost, and other outcome measures is warranted to define the ultimate role of EMDA bladder distention in the clinical evaluation and care of patients with IC
Mood instability, mental illness and suicidal ideas : results from a household survey
Purpose:
There is weak and inconsistent evidence that mood instability (MI) is associated with depression, post traumatic stress disorder (PTSD) and suicidality although the basis of this is unclear. Our objectives were first to test whether there is an association between depression and PTSD, and MI and secondly whether MI exerts an independent effect on suicidal thinking over and above that explained by common mental disorders.
Methods:
We used data from the Adult Psychiatric Morbidity Survey 2007 (N = 7,131). Chi-square tests were used to examine associations between depression and PTSD, and MI, followed by regression modelling to examine associations between MI and depression, and with PTSD. Multiple logistic regression analyses were used to assess the independent effect of MI on suicidal thinking, after adjustment for demographic factors and the effects of common mental disorder diagnoses.
Results:
There are high rates of MI in depression and PTSD and the presence of MI increases the odds of depression by 10.66 [95 % confidence interval (CI) 7.51–15.13] and PTSD by 8.69 (95 % CI 5.90–12.79), respectively, after adjusting for other factors. Mood instability independently explained suicidal thinking, multiplying the odds by nearly five (odds ratio 4.82; 95 % CI 3.39–6.85), and was individually by some way the most important single factor in explaining suicidal thoughts.
Conclusions:
MI is strongly associated with depression and PTSD. In people with common mental disorders MI is clinically significant as it acts as an additional factor exacerbating the risk of suicidal thinking. It is important to enquire about MI as part of clinical assessment and treatment studies are required
The "Solar Model Problem" Solved by the Abundance of Neon in Stars of the Local Cosmos
The interior structure of the Sun can be studied with great accuracy using
observations of its oscillations, similar to seismology of the Earth. Precise
agreement between helioseismological measurements and predictions of
theoretical solar models has been a triumph of modern astrophysics (Bahcall et
al. 2005). However, a recent downward revision by 25-35% of the solar
abundances of light elements such as C, N, O and Ne (Asplund et al. 2004) has
broken this accordance: models adopting the new abundances incorrectly predict
the depth of the convection zone, the depth profiles of sound speed and
density, and the helium abundance (Basu Antia 2004, Bahcall et al. 2005). The
discrepancies are far beyond the uncertainties in either the data or the model
predictions (Bahcall et al. 2005b). Here we report on neon abundances relative
to oxygen measured in a sample of nearby solar-like stars from their X-ray
spectra. They are all very similar and substantially larger than the recently
revised solar value. The neon abundance in the Sun is quite poorly determined.
If the Ne/O abundance in these stars is adopted for the Sun the models are
brought back into agreement with helioseismology measurements (Antia Basu 2005,
Bahcall et al. 2005c).Comment: 13 pages, 3 Figure
How often should we monitor for reliable detection of atrial fibrillation recurrence? Efficiency considerations and implications for study design
OBJECTIVE: Although atrial fibrillation (AF) recurrence is unpredictable in terms of onset and duration, current intermittent rhythm monitoring (IRM) diagnostic modalities are short-termed and discontinuous. The aim of the present study was to investigate the necessary IRM frequency required to reliably detect recurrence of various AF recurrence patterns. METHODS: The rhythm histories of 647 patients (mean AF burden: 12±22% of monitored time; 687 patient-years) with implantable continuous monitoring devices were reconstructed and analyzed. With the use of computationally intensive simulation, we evaluated the necessary IRM frequency to reliably detect AF recurrence of various AF phenotypes using IRM of various durations. RESULTS: The IRM frequency required for reliable AF detection depends on the amount and temporal aggregation of the AF recurrence (p<0.0001) as well as the duration of the IRM (p<0.001). Reliable detection (>95% sensitivity) of AF recurrence required higher IRM frequencies (>12 24-hour; >6 7-day; >4 14-day; >3 30-day IRM per year; p<0.0001) than currently recommended. Lower IRM frequencies will under-detect AF recurrence and introduce significant bias in the evaluation of therapeutic interventions. More frequent but of shorter duration, IRMs (24-hour) are significantly more time effective (sensitivity per monitored time) than a fewer number of longer IRM durations (p<0.0001). CONCLUSIONS: Reliable AF recurrence detection requires higher IRM frequencies than currently recommended. Current IRM frequency recommendations will fail to diagnose a significant proportion of patients. Shorter duration but more frequent IRM strategies are significantly more efficient than longer IRM durations. CLINICAL TRIAL REGISTRATION URL: Unique identifier: NCT00806689
Species replacement dominates megabenthos beta diversity in a remote seamount setting
Seamounts are proposed to be hotspots of deep-sea biodiversity, a pattern potentially arising from increased productivity in a heterogeneous landscape leading to either high species co-existence or species turnover (beta diversity). However, studies on individual seamounts remain rare, hindering our understanding of the underlying causes of local changes in beta diversity. Here, we investigated processes behind beta diversity using ROV video, coupled with oceanographic and quantitative terrain parameters, over a depth gradient in Annan Seamount, Equatorial Atlantic. By applying recently developed beta diversity analyses, we identified ecologically unique sites and distinguished between two beta diversity processes: species replacement and changes in species richness. The total beta diversity was high with an index of 0.92 out of 1 and was dominated by species replacement (68%). Species replacement was affected by depth-related variables, including temperature and water mass in addition to the aspect and local elevation of the seabed. In contrast, changes in species richness component were affected only by the water mass. Water mass, along with substrate also affected differences in species abundance. This study identified, for the first time on seamount megabenthos, the different beta diversity components and drivers, which can contribute towards understanding and protecting regional deep-sea biodiversity
Dual Identities inside the Gluon and the Graviton Scattering Amplitudes
Recently, Bern, Carrasco and Johansson conjectured dual identities inside the
gluon tree scattering amplitudes. In this paper, we use the properties of the
heterotic string and open string tree scattering amplitudes to refine and
derive these dual identities. These identities can be carried over to loop
amplitudes using the unitarity method. Furthermore, given the -gluon (as
well as gluon-gluino) tree amplitudes, -graviton (as well as
graviton-gravitino) tree scattering amplitudes can be written down immediately,
avoiding the derivation of Feynman rules and the evaluation of Feynman diagrams
for graviton scattering amplitudes.Comment: 43 pages, 3 figures; typos corrected, a few points clarified
The results of arthroscopic anterior stabilisation of the shoulder using the bioknotless anchor system
<p>Abstract</p> <p>Background</p> <p>Shoulder instability is a common condition, particularly affecting a young, active population. Open capsulolabral repair is effective in the majority of cases, however arthroscopic techniques, particularly using suture anchors, are being used with increasing success.</p> <p>Methods</p> <p>15 patients with shoulder instability were operated on by a single surgeon (VK) using BioKnotless anchors (DePuy Mitek, Raynham, MA). The average length of follow-up was 21 months (17 to 31) with none lost to follow-up. Constant scores in both arms, patient satisfaction, activity levels and recurrence of instability was recorded.</p> <p>Results</p> <p>80% of patients were satisfied with their surgery. 1 patient suffered a further dislocation and another had recurrent symptomatic instability. The average constant score returned to 84% of that measured in the opposite (unaffected) shoulder. There were no specific post-operative complications encountered.</p> <p>Conclusion</p> <p>In terms of recurrence of symptoms, our results show success rates comparable to other methods of shoulder stabilisation. This technique is safe and surgeons familiar with shoulder arthroscopy will not encounter a steep learning curve. Shoulder function at approximately 2 years post repair was good or excellent in the majority of patients and it was observed that patient satisfaction was correlated more with return to usual activities than recurrence of symptoms.</p
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