Nuclear-Medium Modification of the Rho(1S)- and Rhoprim(2S)-Mesons in Coherent Photo- and Electroproduction: Coupled Channel Analysis

We study medium modifications of the dilepton mass spectrum in coherent photo- and electroproduction of the Rho(1S)- and Rhoprim(2S)-meson resonances on nuclear targets. The analysis is performed within the coupled Rho, Rhoprim... channel formalism in which nuclear modifications derive from the off-diagonal rescatterings. We find that the effect of off-diagonal rescatterings on the shape of the dilepton mass spectrum in the Rho(1S)-meson mass region is only marginal but is very important in the Rhoprim mass region. The main off-diagonal contribution in the Rhoprim mass region comes from the sequential mechanism gamma* -> Rho -> Rhoprim(2S), which dominates the Rhoprim(2S) production for heavy nuclei. Our results show also that in the Rhoprim(2S) mass region there is a considerable effect of the interference of the Breit-Wigner tail of Rho(1S)-meson with the Rhoprim-meson.Comment: 18 pages, 9 figure

The impact of immediate breast reconstruction on the time to delivery of adjuvant therapy: the iBRA-2 study

Background: Immediate breast reconstruction (IBR) is routinely offered to improve quality-of-life for women requiring mastectomy, but there are concerns that more complex surgery may delay adjuvant oncological treatments and compromise long-term outcomes. High-quality evidence is lacking. The iBRA-2 study aimed to investigate the impact of IBR on time to adjuvant therapy. Methods: Consecutive women undergoing mastectomy ± IBR for breast cancer July–December, 2016 were included. Patient demographics, operative, oncological and complication data were collected. Time from last definitive cancer surgery to first adjuvant treatment for patients undergoing mastectomy ± IBR were compared and risk factors associated with delays explored. Results: A total of 2540 patients were recruited from 76 centres; 1008 (39.7%) underwent IBR (implant-only [n = 675, 26.6%]; pedicled flaps [n = 105,4.1%] and free-flaps [n = 228, 8.9%]). Complications requiring re-admission or re-operation were significantly more common in patients undergoing IBR than those receiving mastectomy. Adjuvant chemotherapy or radiotherapy was required by 1235 (48.6%) patients. No clinically significant differences were seen in time to adjuvant therapy between patient groups but major complications irrespective of surgery received were significantly associated with treatment delays. Conclusions: IBR does not result in clinically significant delays to adjuvant therapy, but post-operative complications are associated with treatment delays. Strategies to minimise complications, including careful patient selection, are required to improve outcomes for patients

Using in-situ strain measurements to evaluate the accuracy of stress estimation procedures from fracture injection/shut-in tests

Fracture injection/shut-in tests are commonly used to measure the state of stress in the subsurface. Injection creates a hydraulic fracture (or in some cases, opens a preexisting fracture), and then the pressure after shut-in is monitored to identify fracture closure. Different interpretation procedures have been proposed for estimating closure, and the procedures sometimes yield significantly different results. In this study, direct, in-situ strain measurements are used to observe fracture reopening and closure. The tests were performed as part of the EGS Collab project, a mesoscale project performed at 1.25 and 1.5 km depth at the Sanford Underground Research Facility. The tests were instrumented with the SIMFIP tool, a double-packer probe with a high-resolution three-dimensional borehole displacement sensor. The measurements provide a direct observation of the fracture closure signature, enabling a high-fidelity estimate of the fracture closure stress (ie, the normal stress on the fracture). In two of the four tests, injection created an opening mode fracture, and so the closure stress can be interpreted as the minimum principal stress. In the other two tests, injection probably opened preexisting natural fractures, and so the closure stress can be interpreted as the normal stress on the fractures. The strain measurements are compared against different proposed methods for estimating closure stress from pressure transients. The shut-in transients are analyzed with two techniques that are widely used in the field of petroleum engineering – the ‘tangent’ method and the ‘compliance’ method. In three of the four tests, the tangent method significantly underestimates the closure stress. The compliance method is reasonably accurate in all four tests. Closure stress is also interpreted using two other commonly-used methods – ‘first deviation from linearity’ and the method of (Hayashi and Haimson, 1991). In comparison with the SIMFIP data, these methods tend to overestimate the closure stress, evidently because they identify closure from early-time transient effects, such as near-wellbore tortuosity. In two of the tests, microseismic imaging provides an independent estimate of the size of the fracture created by injection. When combined with a simple mass balance calculation, the SIMFIP stress measurements yield predictions of fracture size that are reasonably consistent with the estimates from microseismic. The calculations imply an apparent fracture toughness 2-3x higher than typical laboratory-derived values

Intermittency in hadronic decays of the Z0

Contains fulltext : 125116.pdf (preprint version ) (Open Access

Measurement of the partial width of the Z0 into b anti-b final states using their semileptonic decays

The spectra of prompt electrons and muons from the semi-leptonic decays of heavy hadrons produced inZ 0 decays have been used to measure the coupling of theZ 0 tob quarks weighted by theB hadrons mean semi-leptonic branching fraction, giving a value: BRbsl∗Γbbˉ/ΓH=0.0221±0.0015 . The data has also been used to measure the value of the fragmentation parameter, defined in the context of the LUND PS Model, version 7.2, giving: ε(b)=(8+5−3±2)10−3 . The corresponding value of the mean fraction of the beam energy taken by aB hadron in the fragmentation of ab quark is: XbE−−−=0.69+0.02−0.03±0.01 . If the values of Γbbˉ andΓ H are taken from the Standard Model, the following value is obtained for the mean semi-leptonic braching fraction ofB hadrons: BR sl b =(10.1±0.7)%. Taking the value of Γbbˉ/ΓH from an independent analysis of DELPHI data based on the use of the boosted sphericity product, a value: BR sl b =(10.1±1.3)% is obtained

Relationship between method of anastomosis and anastomotic failure after right hemicolectomy and ileo-caecal resection: an international snapshot audit

Aim The anastomosis technique used following right-sided colonic resection is widely variable and may affect patient outcome. This study aimed to assess the association between leak and anastomosis technique (stapled vs handsewn). Method This was a prospective, multicentre, international audit including patients undergoing elective or emergency right hemicolectomy or ileo-caecal resection operations over a 2-month period in early 2015. The primary outcome measure was the presence of anastomotic leak within 30 days of surgery, determined using a prespecified definition. Mixed effects logistic regression models were used to assess the association between leak and anastomosis method, adjusting for patient, disease and operative cofactors, with centre included as a random-effect variable. Results This study included 3208 patients, of whom 78.4\% (n = 2515) underwent surgery for malignancy and 11.7\% (n = 375) underwent surgery for Crohn's disease. An anastomosis was performed in 94.8\% (n = 3041) of patients, which was handsewn in 38.9\% (n = 1183) and stapled in 61.1\% (n = 1858). Patients undergoing hand-sewn anastomosis were more likely to be emergency admissions (20.5\% handsewn vs 12.9\% stapled) and to undergo open surgery (54.7\% handsewn vs 36.6\% stapled). The overall anastomotic leak rate was 8.1\% (245/3041), which was similar following handsewn (7.4\%) and stapled (8.5\%) techniques (P = 0.3). After adjustment for cofactors, the odds of a leak were higher for stapled anastomosis (adjusted OR = 1.43; 95\% CI: 1.04-1.95; P = 0.03). Conclusion Despite being used in lower-risk patients, stapled anastomosis was associated with an increased anastomotic leak rate in this observational study. Further research is needed to define patient groups in whom a stapled anastomosis is safe