Counting to one: reducibility of one- and two-loop amplitudes at the integrand level

Calculation of amplitudes in perturbative quantum field theory involve large loop integrals. The complexity of those integrals, in combination with the large number of Feynman diagrams, make the calculations very difficult. Reduction methods proved to be very helpful, lowering the number of integrals that need to be actually calculated. Especially, the reduction at the integrand level technique, improves the speed and set-up of these calculations. In this article we demonstrate, by counting the numbers of tensor structures and independent coefficients, how to write such relations at the integrand level for one- and two-loop amplitudes. We clarify their connection to the so-called spurious terms at one loop and discuss their structure in the two-loop case. This method is also applicable to higher loops, and the results obtained apply to both planar and non-planar diagrams

Examining intervention mechanisms of action using mediation analysis within a randomised trial of a whole-school health intervention

BACKGROUND: Interventions to modify school environments are effective in promoting young people's health across outcomes, but mechanisms are poorly understood. We assessed mediation in a trial of the Learning Together intervention, building on the recent publication of results of effectiveness for reducing bullying and benefits across secondary outcomes and generally good implementation fidelity. METHODS: Within a cluster-randomised trial involving 40 English schools, we examined student-reported and staff-reported school climate and student-reported involvement with delinquent peers at 24-month and 36-month follow-up, assessing the reliability of measures and whether these mediated health outcomes at a final follow-up. RESULTS: Response rates and reliability were good for student-reported but not staff-reported measures. The intervention increased student-reported but not staff-reported-positive school climate but, like effects on student health outcomes, these manifested only at a final follow-up. The intervention reduced student-reported contact with delinquent peers at an interim follow-up. Student-reported potential mediators measured at the interim follow-up were associated with most health outcomes at the final follow-up. Adjustment for student-reported school climate and contact with delinquent peers at the interim follow-up did not reduce the associations between trial arm and our health outcomes. CONCLUSION: Despite being constrained by imperfect measures and by the late manifestation of impacts on student-reported school climate undermining ability to assess mediation, our study for the first time provides tentative evidence that mediation of intervention effects via improved climate and disengagement from delinquent peers is plausible. Our study provides the first evidence from a trial that whole-school interventions may work by modifying school environments and student relationships. TRIAL REGISTRATION NUMBER: ISRCTN10751359

Effects of school environments on student risk-behaviours: evidence from a longitudinal study of secondary schools in England

BACKGROUND: The theory of human functioning and school organisation proposes that schools with rigid 'boundaries' (weaker relationships), for example, between staff and students, or learning and broader development, engender weaker student school commitment and sense of belonging, particularly among disadvantaged students, leading to greater involvement in risk-behaviours. Existing studies provide some support but rely on a proxy exposure of 'value-added education' and have not explored effects by disadvantage. METHODS: We used longitudinal data from English secondary schools from the control arm of a trial, assessing school-level measures of rigid boundaries, and student commitment and belonging at age 11/12, and student risk-behaviours at age 14/15. RESULTS: Our direct measures were more strongly associated with risk-behaviours than was value-added education. School-level rigid boundaries were associated with increased alcohol use and bullying. Student belonging was more consistently associated with reduced risk-behaviours than was student commitment. Some school effects were greater for students from disadvantaged subgroups defined in terms of poverty, ethnicity and family structure. CONCLUSION: Our results provide direct support for the theory of human functioning and school organisation and suggest a sense of belonging in school might be particularly protective factor among secondary school students. School effects on risk are generally stronger among disadvantaged students as theorised. TRIAL REGISTRATION NUMBER: ISRCTN10751359

Scaling Patterns for QCD Jets

Jet emission at hadron colliders follows simple scaling patterns. Based on perturbative QCD we derive Poisson and staircase scaling for final state as well as initial state radiation. Parton density effects enhance staircase scaling at low multiplicities. We propose experimental tests of our theoretical findings in Z+jets and QCD gap jets production based on minor additions to current LHC analyses.Comment: 36 pages, 16 figure

Payment for performance (P4P): any future in Italy?

<p>Abstract</p> <p>Background</p> <p>Pay for Performance (P4P) programs, based on provision of financial incentives for service quality, have been widely adopted to enhance quality of care and to promote a more efficient use of health care resources whilst improving patient outcomes. In Italy, as in other countries, the growing concern over the quality of health services provided and the scarcity of resources would make P4P programs a useful means of improving their performance. The aim of this paper is to evaluate whether it is possible to implement P4P programs in the Lombardy Region, in Italy, based on the existing data set.</p> <p>Methods</p> <p>Thirteen quality measures were identified regarding four clinical conditions (acute myocardial infarction (AMI), heart failure (HF), ischemic stroke and hip and knee replacement) on the basis of an international literature review. Data was collected using the database of three institutions, which included hospital discharge records (Scheda di Dimissione ospedaliera-SDO-) and letters of discharge. The study population was identified using both the Principal ICD-9-CM diagnosis codes and the discharge date. A Statistical Analysis System (SAS) program was used for the text analysis.</p> <p>Results</p> <p>It was possible to calculate almost all the parameters pertaining to the three hospitals as all the data required was available with the exception of inpatient mortality in two hospitals and smoking cessation advice/counseling in one hospital.</p> <p>Conclusions</p> <p>On the ground of this analysis, we believe that it is possible to implement a P4P program in the Lombardy Region. However, for this program to be initiated, all necessary data must be available in electronic format and uniformly collected. Moreover, several other factors must be assessed: which clinical conditions should be included, the threshold for each quality parameter, the amount of financial incentives offered and how they will be provided.</p

Visualization of Allostery in P-Selectin Lectin Domain Using MD Simulations

Allostery of P-selectin lectin (Lec) domain followed by an epithelial growth factor (EGF)-like domain is essential for its biological functionality, but the underlying pathways have not been well understood. Here the molecular dynamics simulations were performed on the crystallized structures to visualize the dynamic conformational change for state 1 (S1) or state 2 (S2) Lec domain with respective bent (B) or extended (E) EGF orientation. Simulations illustrated that both S1 and S2 conformations were unable to switch from one to another directly. Instead, a novel S1' conformation was observed from S1 when crystallized B-S1 or reconstructed “E-S1” structure was employed, which was superposed well with that of equilibrated S1 Lec domain alone. It was also indicated that the corresponding allosteric pathway from S1 to S1' conformation started with the separation between residues Q30 and K67 and terminated with the release of residue N87 from residue C109. These results provided an insight into understanding the structural transition and the structure-function relationship of P-selectin allostery

The role of family and school-level factors in bullying and cyberbullying: a cross sectional study

Background: Bullying and cyberbullying are common phenomena in schools. These negative behaviours can have a significant impact on the health and particularly mental health of those involved in such behaviours, both as victims and as bullies. This UK study aims to investigate student-level and school-level characteristics of those who become involved in bullying and cyberbullying behaviours as victims or perpetrators. Methods: We used data from 6667 Year 7 students from the baseline survey of a cluster randomized trial in 40 English schools to investigate the associations between individual-level and school-level variables with bullying victimization, cyberbullying perpetration, and cyberbullying victimization. We ran multilevel models to examine associations of bullying outcomes with individual-level variables and school-level variables. Results: In multilevel models, at the school level, school type and school quality measures were associated with bullying risk: students in voluntary-aided schools were less likely to report bullying victimization (0.6 (0.4, 0.9) p = 0.008), and those in community (3.9 (1.5, 10.5) p = 0.007) and foundation (4.0 (1.6, 9.9) p = 0.003) schools were more likely to report being perpetrators of cyberbullying than students in mainstream academies. A school quality rating of “Good” was associated with greater reported bullying victimization (1.3 (1.02, 1.5) p = 0.03) compared to ratings of “Outstanding.” Conclusions: Bullying victimization and cyberbullying prevalence vary across school type and school quality, supporting the hypothesis that organisational/management factors within the school may have an impact on students’ behaviour. These findings will inform future longitudinal research investigating which school factors and processes promote or prevent bullying and cyberbullying behaviours. Trial registration: Trial ID: ISRCTN10751359 Registered: 11/03/2014 (retrospectively registered)

Approaches to link RNA secondary structures with splicing regulation

In higher eukaryotes, alternative splicing is usually regulated by protein factors, which bind to the pre-mRNA and affect the recognition of splicing signals. There is recent evidence that the secondary structure of the pre-mRNA may also play an important role in this process, either by facilitating or by hindering the interaction with factors and small nuclear ribonucleoproteins (snRNPs) that regulate splicing. Moreover, the secondary structure could play a fundamental role in the splicing of yeast species, which lack many of the regulatory splicing factors present in metazoans. This review describes the steps in the analysis of the secondary structure of the pre-mRNA and its possible relation to splicing. As a working example, we use the case of yeast and the problem of the recognition of the 3-prime splice site.Comment: 21 pages, 7 figure

Adjuvant radiation therapy in metastatic lymph nodes from melanoma

<p>Abstract</p> <p>Purpose</p> <p>To analyze the outcome after adjuvant radiation therapy with standard fractionation regimen in metastatic lymph nodes (LN) from cutaneous melanoma.</p> <p>Patients and methods</p> <p>86 successive patients (57 men) were treated for locally advanced melanoma in our institution. 60 patients (69%) underwent LN dissection followed by radiation therapy (RT), while 26 patients (31%) had no radiotherapy.</p> <p>Results</p> <p>The median number of resected LN was 12 (1 to 36) with 2 metastases (1 to 28). Median survival after the first relapse was 31.8 months. Extracapsular extension was a significant prognostic factor for regional control (p = 0.019). Median total dose was 50 Gy (30 to 70 Gy). A standard fractionation regimen was used (2 Gy/fraction). Median number of fractions was 25 (10 to 44 fractions). Patients were treated with five fractions/week. Patients with extracapsular extension treated with surgery followed by RT (total dose ≥50 Gy) had a better regional control than patients treated by surgery followed by RT with a total dose <50 Gy (80% vs. 35% at 5-year follow-up; p = 0.004).</p> <p>Conclusion</p> <p>Adjuvant radiotherapy was able to increase regional control in targeted sub-population (LN with extracapsular extension).</p

Effects of the Learning Together intervention on bullying and aggression in English secondary schools (INCLUSIVE): a cluster randomised controlled trial

BACKGROUND: Bullying, aggression, and violence among children and young people are some of the most consequential public mental health problems. We tested the Learning Together intervention, which involved students in efforts to modify their school environment using restorative practice and by developing social and emotional skills. METHODS: We did a cluster randomised trial, with economic and process evaluations, of the Learning Together intervention compared with standard practice (controls) over 3 years in secondary schools in south-east England. Learning Together consisted of staff training in restorative practice; convening and facilitating a school action group; and a student social and emotional skills curriculum. Primary outcomes were self-reported experience of bullying victimisation (Gatehouse Bullying Scale; GBS) and perpetration of aggression (Edinburgh Study of Youth Transitions and Crime (ESYTC) school misbehaviour subscale) measured at 36 months. We analysed data using intention-to-treat longitudinal mixed-effects models. This trial was registered with the ISRCTN registry (10751359). FINDINGS: We included 40 schools (20 in each group); no schools withdrew. 6667 (93·6%) of 7121 students participated at baseline and 5960 (83·3%) of 7154 at 36 months. Mean GBS bullying score at 36 months was 0·34 (SE 0·02) in the control group versus 0·29 (SE 0·02) in the intervention group, with a significant adjusted mean difference (-0·03, 95% CI -0·06 to -0·001; adjusted effect size -0·08). Mean ESYTC score at 36 months was 4·33 (SE 0·20) in the control group versus 4·04 (0·21) in the intervention group, with no evidence of a difference between groups (adjusted difference -0·13, 95% CI -0·43 to 0·18; adjusted effect size -0·03). Costs were an additional £58 per pupil in intervention schools than in control schools. INTERPRETATION: Learning Together had small but significant effects on bullying, which could be important for public health, but no effect on aggression. Interventions to promote student health by modifying the whole-school environment are likely to be one of the most feasible and efficient ways of addressing closely related risk and health outcomes in children and young people. FUNDING: National Institute for Health Research, Educational Endowment Foundation