Compton scattering in strong magnetic fields: Spin-dependent influences at the cyclotron resonance

The quantum electrodynamical (QED) process of Compton scattering in strong magnetic fields is commonly invoked in atmospheric and inner magnetospheric models of x-ray and soft gamma-ray emission in high-field pulsars and magnetars. A major influence of the field is to introduce resonances at the cyclotron frequency and its harmonics, where the incoming photon accesses thresholds for the creation of virtual electrons or positrons in intermediate states with excited Landau levels. At these resonances, the effective cross section typically exceeds the classical Thomson value by over 2 orders of magnitude. Near and above the quantum critical magnetic field of 44.13 TeraGauss, relativistic corrections must be incorporated when computing this cross section. This paper presents formalism for the QED magnetic Compton differential cross section valid for both subcritical and supercritical fields, yet restricted to scattered photons that are below pair creation threshold. Calculations are developed for the particular case of photons initially propagating along the field, mathematically simple specializations that are germane to interactions involving relativistic electrons frequently found in neutron star magnetospheres. This exposition of relativistic, quantum, magnetic Compton cross sections treats electron spin dependence fully, since this is a critical feature for describing the finite decay lifetimes of the intermediate states. The formalism employs both the Johnson and Lippmann (JL) wave functions and the Sokolov and Ternov (ST) electron eigenfunctions of the magnetic Dirac equation. The ST states are formally correct for self-consistently treating spin-dependent effects that are so important in the resonances. Relatively compact analytic forms for the cross sections are presented that will prove useful for astrophysical modelers.Comment: 45 pages, 10 figures, accepted for publication in Phys. Rev.

Going beyond (electronic) patient-reported outcomes: harnessing the benefits of smart technology and ecological momentary assessment in cancer survivorship research

Rapid developments in digital mobile and sensor technology have facilitated the active and passive collection of detailed, personalized data in increasingly affordable ways. Researchers may be familiar with the daily diary, portable computers, or the pedometer for the collection of patientreported outcomes (PRO) in cancer survivorship research. Such methods, termed ecological momentary assessment (EMA), have evolved with technological advances, e.g., collecting data or providing interventions (ecological momentary intervention, EMI) via apps or devices such as smartphones. These smart technology-adapted sEMA/ sEMI methods are more widely used in affective disorders or addictive behavior research but are currently still under-utilized in cancer survivorship research. A recent scoping review on the use of active EMA among cancer survivors identified twelve articles published between 1993 and 2018. Most of the included studies in that review used portable computers. This commentary will discuss the utility of sEMA/sEMI in cancer survivorship research and call for action to advance this area of science

Development of an occupational advice intervention for patients undergoing lower limb arthroplasty (the OPAL study)

Background: There are an increasing number of patients of working age undergoing hip and knee replacements. Currently there is variation in the advice and support given about sickness absence, recovery to usual activities and return to work after these procedures. Earlier, sustainable, return to work improves the health of patients and benefits their employers and society. An intervention that encourages and supports early recovery to usual activities, including work, has the potential to reduce the health and socioeconomic burden of hip and knee replacements. Methods/design: A two-phase research programme delivered over 27 months will be used to develop and subsequently test the feasibility of an occupational advice intervention to facilitate return to work and usual activities in patients undergoing lower limb arthroplasty. The 2 phases will incorporate a six-stage intervention mapping process: Phase 1: Intervention mapping stages 1–3: 1 Needs assessment (including rapid evidence synthesis, prospective cohort analysis and structured stakeholder interviews) 2 Identification of intended outcomes and performance objectives 3 Selection of theory-based methods and practical strategies Phase 2: Intervention mapping stages 4–6: 4 Development of components and materials for the occupational advice intervention using a modified Delphi process 5 Adoption and implementation of the intervention 6 Evaluation and feasibility testing The study will be undertaken in four National Health Service (NHS) hospitals in the United Kingdom and two Higher Education Institution. Discussion: OPAL (Occupational advice for Patients undergoing Arthroplasty of the Lower limb) aims to develop an occupational advice intervention to support early recovery to usual activities including work, which is tailored to the requirements of patients undergoing hip and knee replacements. The developed intervention will then be assessed with a specific focus on evaluating its feasibility as a potential trial intervention to improve speed of recovery to usual activities including work

User's perspectives of barriers and facilitators to implementing quality colonoscopy services in Canada: a study protocol

<p>Abstract</p> <p>Background</p> <p>Colorectal cancer (CRC) represents a serious and growing health problem in Canada. Colonoscopy is used for screening and diagnosis of symptomatic or high CRC risk individuals. Although a number of countries are now implementing quality colonoscopy services, knowledge synthesis of barriers and facilitators perceived by healthcare professionals and patients during implementation has not been carried out. In addition, the perspectives of various stakeholders towards the implementation of quality colonoscopy services and the need of an efficient organisation of such services have been reported in the literature but have not been synthesised yet. The present study aims to produce a comprehensive synthesis of actual knowledge on the barriers and facilitators perceived by all stakeholders to the implementation of quality colonoscopy services in Canada.</p> <p>Methods</p> <p>First, we will conduct a comprehensive review of the scientific literature and other published documentation on the barriers and facilitators to implementing quality colonoscopy services. Standardised literature searches and data extraction methods will be used. The quality of the studies and their relevance to informing decisions on colonoscopy services implementation will be assessed. For each group of users identified, barriers and facilitators will be categorised and compiled using narrative synthesis and meta-analytical techniques. The principle factors identified for each group of users will then be validated for its applicability to various Canadian contexts using the Delphi study method. Following this study, a set of strategies will be identified to inform decision makers involved in the implementation of quality colonoscopy services across Canadian jurisdictions.</p> <p>Discussion</p> <p>This study will be the first to systematically summarise the barriers and facilitators to implementation of quality colonoscopy services perceived by different groups and to consider the local contexts in order to ensure the applicability of this knowledge to the particular realities of various Canadian jurisdictions. Linkages with strategic partners and decision makers in the realisation of this project will favour the utilisation of its results to support strategies for implementing quality colonoscopy services and CRC screening programs in the Canadian health system.</p

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

A gestural repertoire of 1-2year old human children : in search of the ape gestures

This project was made possible with the generous financial help of the Baverstock Bequest to the Psychology and Neuroscience Department at the University of St Andrews.When we compare human gestures to those of other apes, it looks at first like there is nothing much to compare at all. In adult humans, gestures are thought to be a window into the thought processes accompanying language, and sign languages are equal to spoken language with all of its features. While some research firmly emphasises the difference between human gestures and those of other apes, the question about whether there are any commonalities has rarely been investigated, and is mostly confined to pointing gestures. The gestural repertoires of nonhuman ape species have been carefully studied and described with regard to their form and function – but similar approaches are much rarer in the study of human gestures. This paper applies the methodology commonly used in the study of nonhuman ape gestures to the gestural communication of human children in their second year of life. We recorded (n=13) children’s gestures in a natural setting with peers and caregivers in Germany and Uganda. Children employed 52 distinct gestures, 46 (89%) of which are present in the chimpanzee repertoire. Like chimpanzees, they used them both singly, and in sequences; and employed individual gestures flexibly towards different goals.Publisher PDFPeer reviewe

Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals

Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice

A new strategy for linking U.S. historical censuses : A case study for the IPUMS multigenerational longitudinal panel

This paper presents a probabilistic method of record linkage, developed using the U.S. full count censuses of 1900 and 1910 but applicable to many sources of digitized historical records. The method links records using a two-step approach, first establishing high confidence matches among men by exploiting a comprehensive set of individual and contextual characteristics. The method then proceeds to link both men and women by leveraging links between households established in the first step. While only the first stage links can be directly comparable to other popular methods in research on the U.S., our method yields both considerably higher linkage rates and greater accuracy while only performing negligibly worse than other algorithms in resembling the target population