Analytic perturbation theory in QCD and Schwinger's connection between the beta-function and the spectral density

We argue that a technique called analytic perturbation theory leads to a well-defined method for analytically continuing the running coupling constant from the spacelike to the timelike region, which allows us to give a self-consistent definition of the running coupling constant for timelike momentum. The corresponding $\beta$-function is proportional to the spectral density, which confirms a hypothesis due to Schwinger.Comment: 11 pages, 2 figure

Repeatability and comparison of clinical techniques for anterior chamber angle assessment

Purpose To assess the repeatability of gonioscopy, van Herick method and anterior segment Optical Coherence Tomography (AS-OCT) and determine the agreement between these techniques within a community optometry setting. Methods Gonioscopy, van Herick method and AS-OCT imaging were performed by an optometrist on two occasions, 1 month apart, on 80 subjects aged over 40 years recruited from community optometry practices. Anterior segment images were captured with a spectral domain OCT (Topcon 3D OCT-2000; wavelength 840 nm) set to the Anterior Segment (AS) mode. Eyes were graded as open or occludable for each method. AS-OCT images from both visits were graded by a second optometrist masked to the gonioscopy and van Herick method results, and the visit on which the images were acquired. Cohen's kappa (κ) was used to describe the intra-observer repeatability. Likelihood ratios, sensitivity and specificity of van Herick method and AS-OCT were calculated, using gonioscopy as the reference standard. Results Measurements were obtained from 80 eyes of 80 subjects. In four cases, AS-OCT images were un-gradable due to difficulty in locating the scleral spur. The repeatability of gonioscopy was fair κ = 0.29, while that of the van Herick method (κ = 0.54) and AS-OCT (κ = 0.47) were somewhat better. The van Herick method showed good sensitivity (visit 1: 75%, visit 2: 69%) and high specificity (visit 1: 88%, visit 2: 96%). The sensitivity of AS-OCT was fair (visit 1: 46%, visit 2: 25%), but specificity was high (visit 1: 87%. visit 2: 89%). Conclusion Intra-observer repeatability was better for van Herick method and for AS-OCT than for gonioscopy, despite the latter being considered the gold standard method. The van Herick method appeared to be more sensitive than AS-OCT when identifying eyes at risk of angle closure. A standalone anterior segment OCT with a longer wavelength laser could afford better visualisation of the angle, and might therefore be expected to enable the examiner to make more precise classifications. These instruments are not widely used by optometrists in clinical practice in the UK at present

Linking Demographic Effects of Habitat Fragmentation Across Landscapes to Continental Source-Sink Dynamics

Forest fragmentation may cause increased brood parasitism and nest predation of breeding birds. In North America, nest parasitism and predation are expected to increase closer to forest edges because the brood-parasitic Brown-headed Cowbird(Molothrus ater) and generalist nest predators often enter the forest from adjoining developed (largely agricultural) habitats. Yet the abundance of brood parasites and nest predators at the patch scale may be strongly constrained by the total area of developed habitat at landscape scales. The scale and extent of landscape effects are unclear, however, because past studies were mostly conducted within local landscapes rather than across independent landscapes. We report replicated studies from 30 independent landscapes across 17 states of the United States that show that nest parasitism is strongly affected by fragmentation at a 20 km radius scale, equivalent to the maximum foraging range of cowbirds. Nest predation is influenced by both edge and landscape effects, and increases with fragmentation at a 10 km radius scale. Predation is additive to parasitism mortality, and the two together yield decreased population growth potential with increasing forest fragmentation at a 10 km radius scale for 20 of 22 bird species. Mapping of population growth potential across continental landscapes displays broad impacts of fragmentation on population viability and allows geographic prioritization for conservation

Computer recommendations for an automatic approach and landing system for V/STOL aircraft. Volume 2 - Equations

Automatic approach and landing system for V/STOL aircraf

Whole genome sequencing of Plasmodium falciparum from dried blood spots using selective whole genome amplification

BACKGROUND: Translating genomic technologies into healthcare applications for the malaria parasite Plasmodium falciparum has been limited by the technical and logistical difficulties of obtaining high quality clinical samples from the field. Sampling by dried blood spot (DBS) finger-pricks can be performed safely and efficiently with minimal resource and storage requirements compared with venous blood (VB). Here, the use of selective whole genome amplification (sWGA) to sequence the P. falciparum genome from clinical DBS samples was evaluated, and the results compared with current methods that use leucodepleted VB. METHODS: Parasite DNA with high (>95%) human DNA contamination was selectively amplified by Phi29 polymerase using short oligonucleotide probes of 8-12 mers as primers. These primers were selected on the basis of their differential frequency of binding the desired (P. falciparum DNA) and contaminating (human) genomes. RESULTS: Using sWGA method, clinical samples from 156 malaria patients, including 120 paired samples for head-to-head comparison of DBS and leucodepleted VB were sequenced. Greater than 18-fold enrichment of P. falciparum DNA was achieved from DBS extracts. The parasitaemia threshold to achieve >5× coverage for 50% of the genome was 0.03% (40 parasites per 200 white blood cells). Over 99% SNP concordance between VB and DBS samples was achieved after excluding missing calls. CONCLUSION: The sWGA methods described here provide a reliable and scalable way of generating P. falciparum genome sequence data from DBS samples. The current data indicate that it will be possible to get good quality sequence on most if not all drug resistance loci from the majority of symptomatic malaria patients. This technique overcomes a major limiting factor in P. falciparum genome sequencing from field samples, and paves the way for large-scale epidemiological applications

Protocol for a systematic review: Interventions for anxiety in school-aged children with autism spectrum disorder (ASD): a mixed methods systematic review

This review aims to synthesise evidence about interventions to reduce anxiety symptoms in school-aged children with autism spectrum disorder (ASD). While clinical studies will not be excluded per se, this review seeks to move beyond interventions that are relevant only for clinical practice and care in clinical settings and prioritise studies that draw out implications for school-aged children that will help their functioning in real-world settings such as school and the home. To achieve this aim, the review will employ a mixed-methods systematic review which can accommodate the anticipated diverse types of available studies. These studies are likely to use quantitative methods such as quasi-experimental, mixed-methods randomised control trial approaches as well as qualitative methods such as action-research and case-study designs. This publication outlines the methodology which will be used in the systematic review and covers the criteria for inclusion and exclusion of studies in the review, the search strategy to be used for identification of relevant studies, the bibliographic databases and other sources used for searching, the data collection process including the selection process and data synthesis and analysis, and the timeframe for this project

Taming Landau singularities in QCD perturbation theory: The analytic approach 2.0

The aim of this topical article is to outline the fundamental ideas underlying the recently developed Fractional Analytic Perturbation Theory (FAPT) of QCD and present its main calculational tools together with key applications. For this, it is first necessary to review previous methods to apply QCD perturbation theory at low spacelike momentum scales, where the influence of the Landau singularities becomes inevitable. Several concepts are considered and their limitations are pointed out. The usefulness of FAPT is discussed in terms of two characteristic hadronic quantities: the perturbatively calculable part of the pion's electromagnetic form factor in the spacelike region and the Higgs-boson decay into a $b\bar b$ pair in the timelike region. In the first case, the focus is on the optimization of the prediction with respect to the choice of the renormalization scheme and the dependence on the renormalization and the factorization scales. The second case serves to show that the application of FAPT to this reaction reaches already at the four-loop level an accuracy of the order of 1%, avoiding difficulties inherent in the standard perturbative expansion. The obtained results are compared with estimates from fixed-order and contour-improved QCD perturbation theory. Using the brand-new Higgs mass value of about 125 GeV, measured at the Large Hadron Collider (CERN), a prediction for $\Gamma_{H\to b\bar{b}}=2.4 \pm 0.15 {\rm MeV}$ is extracted.Comment: v3: 23 pages, 7 figures, Invited topical article published in Particles and Nuclei with update using the CERN Higgs discovery. Abridged version presented as plenary talk at International Conference on Renormalization Group and Related Topics (RG 2008), Dubna, Russia, September 1 - 5, 2008. v4 typo in Eq. (3) correcte

Older parents of people who have a learning disability : perceptions of future accomodation needs

The aim of this qualitative study was to provide an insight into the perceptions of older parents of learning disabled people on the future accommodation needs of their adult children. Semi-structured interviews were used to seek parental awareness of residential options available, concerns in relation to future accommodation and the preferred accommodation options for their offspring. Four couples who shared the family home with an adult who has a learning disability took part in the study and data was analysed using a step by step form of content analysis as described by Burnard (1991). Emergent themes from transcripts were then organised into main categories The results of this study suggest that older parents are dissatisfied with both statutory and private services, that they have concerns for their non-disabled children and their own ageing. Being a parent to a person who has a learning disability is seen to be a difficult task and yet parents may want to provide support at home for as long a possible. Of the parents who participated in this study, three couples wanted to maintain their adult child at home for as long as possible and the parents who were actively seeking accommodation outside the family home expected to be involved in all aspects of their daughter�s care for the long term future

A cancer-associated, genome protective programme engaging PKCε

Associated with their roles as targets for tumour promoters, there has been a long-standing interest in how members of the protein kinase C (PKC) family act to modulate cell growth and division. This has generated a great deal of observational data, but has for the most part not afforded clear mechanistic insights into the control mechanisms at play. Here, we review the roles of PKCε in protecting transformed cells from non-disjunction. In this particular cell cycle context, there is a growing understanding of the pathways involved, affording biomarker and interventional insights and opportunities

Assessment of the Linkages and Leakages in a Cloud-Based Computing Collaboration among Construction Stakeholders

The uniqueness of the construction industry can be understood in the large volumes of information in terms of paper works, processes, and communication disseminated daily. The voluminous information requires close coordination which cloud based systems offer. The aim of this research is to assess the linkages and leakages in a cloud-based computing collaboration among construction stakeholders. A purposive sampling technique was used in selecting the participants of the study. A questionnaire based instrument was distributed to eighty (80) construction stakeholder in Lagos State, Nigeria. The data collected was analyzed using SPSS v.21. Statistical tools such as frequencies, stacked bars, mean scores, factor analysis, and analysis of variance (ANOVA) were used in the study. The result of the study revealed that construction stakeholders rarely utilize cloud-based technologies for their construction processes. Construction professionals that access cloud based technologies, do so with their smart mobile phones, laptops, and tablet. The study classified the leakages that exist in the use of cloud-based technologies as securitybased factors, cloud-based infrastructure factors, and cloud-based benefits deficiency based factors. In conclusion, the study revealed that the linkages in the use of cloudbased technologies include knowledge sharing, remote access of back-office activities and engendering collaboration among construction stakeholders. It was recommended that construction stakeholders should leverage on the benefits cloud-based technologies has to offer in today’s competitive economy. Construction stakeholdersshould be adequately informed on the available cloud-based computing technologies and the additions it can bring into the construction process. Cloud computing technology vendors should improve on the security and privacy features of the platform for adequate protection of building data