Effect of conductivity between fasteners and aluminum skin on eddy current specimens

The Federal Aviation Administration Airworthiness Assurance Nondestructive Inspection Validation Center (FAA-AANC) and Boeing Commercial Airplane Group are currently developing a study pertaining to the detection of cracks in multi-layered aluminum sheets. The specimen panels model pertinent aspects of the lap splice joints for Boeing 737 aircraft, Line Numbers 292 - 2565. Upon initial characterization of the specimen panels, it became clear that signals produced from a sliding probe at fastener sites were not representative of an in-service lap splice, and therefore, could not be used in a probability of detection experiment. This paper discusses specimen characterization and steps taken to make the specimens useful for nondestructive technology assessment

Assessing the future threat from vivax malaria in the United Kingdom using two markedly different modelling approaches

Background: The world is facing an increased threat from new and emerging diseases, and there is concern that climate change will expand areas suitable for transmission of vector borne diseases. The likelihood of vivax malaria returning to the UK was explored using two markedly different modelling approaches. First, a simple temperature-dependent, process-based model of malaria growth transmitted by Anopheles atroparvus, the historical vector of malaria in the UK. Second, a statistical model using logistic-regression was used to predict historical malaria incidence between 1917 and 1918 in the UK, based on environmental and demographic data. Using findings from these models and saltmarsh distributions, future risk maps for malaria in the UK were produced based on UKCIP02 climate change scenarios. Results: The process-based model of climate suitability showed good correspondence with historical records of malaria cases. An analysis of the statistical models showed that mean temperature of the warmest month of the year was the major factor explaining the distribution of malaria, further supporting the use of the temperature-driven processed-based model. The risk maps indicate that large areas of central and southern England could support malaria transmission today and could increase in extent in the future. Confidence in these predictions is increased by the concordance between the processed-based and statistical models. Conclusion: Although the future climate in the UK is favourable for the transmission of vivax malaria, the future risk of locally transmitted malaria is considered low because of low vector biting rates and the low probability of vectors feeding on a malaria-infected person

Patterns in rational base number systems

Number systems with a rational number $a/b > 1$ as base have gained interest in recent years. In particular, relations to Mahler's 3/2-problem as well as the Josephus problem have been established. In the present paper we show that the patterns of digits in the representations of positive integers in such a number system are uniformly distributed. We study the sum-of-digits function of number systems with rational base $a/b$ and use representations w.r.t. this base to construct normal numbers in base $a$ in the spirit of Champernowne. The main challenge in our proofs comes from the fact that the language of the representations of integers in these number systems is not context-free. The intricacy of this language makes it impossible to prove our results along classical lines. In particular, we use self-affine tiles that are defined in certain subrings of the ad\'ele ring $\mathbb{A}_\mathbb{Q}$ and Fourier analysis in $\mathbb{A}_\mathbb{Q}$. With help of these tools we are able to reformulate our results as estimation problems for character sums

A database of the morphology, ecology and literature of the world's limb‐reduced skinks

Aim Limb-reduced squamates are a convenient model system to investigate macroevolutionary trends in morphology. Here, we provide morphological, ecological and literature data on all known species of limb-reduced skinks (Scincidae) and their relatives, representing one of the most diverse and widely distributed groups of limb-reduced squamates. Location Global. Taxon Skinks (Reptilia, Squamata: Scincidae). Limb-reduced forms. Methods Morphological data were sourced from the primary literature, spanning a period of over 150 years. Linear body measurements were averaged across all values in the literature, preserving proportionality to body length. For digits and presacral vertebrae, we used maximum recorded counts. Ecological and biogeographical data were sourced from habitat assessments in the primary literature, online databases and field guides. Literature data were sorted according to type of study. To exemplify the applicability of the database, we used Markov-chain ordered models to estimate the evolutionary frequency of limb reduction and loss in skinks. Results We find evidence of limb reduction and loss in a total of 394 species worldwide, representing ~23% of all skink species, and ~30% of genera. The distribution of limb-reduced and limbless forms differs from that of fully limbed forms, as they are present in all biogeographic realms with the almost complete exclusion of the Americas. We estimate that limb reduction evolved more than 50 times in skinks, and that loss of at least one limb pair evolved at least 24 times. Main conclusions The dataset captures a broad spectrum of morphological and ecological variation in a large, globally distributed taxonomic group. It establishes a widely applicable definition of limb reduction based on limb proportions as a reference for future studies. Such an extensive collection of morphological and ecological data can pave the way for investigations of dramatic morphological transitions and their ecological drivers at a global and local scale

Macroecological and biogeographical patterns of limb reduction in the world's skinks

First published: 08 December 2022Aim: Limb reduction is a dramatic evolutionary transition, yet whether it is achieved in similar trajectories across clades, and its environmental drivers, remain unclear. We investigate the macroevolutionary and biogeographical patterns of limb reduction in skinks, where limb reduction occurred more often than in any other tetrapod clade, and test their associations with substrate categories using a global database. We test for habitat associations of body shapes in a group of Australian skinks using quantitative habitat data. Location: Global (Scincidae), Australia (Sphenomorphinae). Taxon: Skinks, Australian Sphenomorphinae. Materials and Methods: We use morphological data to explore the patterns of limb reduction in the world's skinks, investigating how body proportions differ across skink clades and subfamilies. We examine the relationships between body shape and substrate (coarsely classified). Further, we investigate the relationships between body shape and high-resolution soil and climate properties extracted from each species' distribution for Australian sphenomorphines. Results: Relationships between limb lengths and trunk elongation show idiosyncratic patterns across skink clades. Presacral vertebrae numbers positively correlate with trunk elongation in all taxa, except Glaphyromorphus. Skinks from sandy habitats show greater disparity between forelimb and hindlimb lengths than all other substrate categories. In sphenomorphines, shorter limbs and elongated trunks correlate with colder, more humid microhabitats and richer soils; high limb disparity correlates with hot, arid microhabitats and sandy, poor substrates. Main Conclusions: The evolutionary trajectories of limb reduction in skinks are cladespecific and sometimes unique. Selection for specific limb proportions and body sizes in limb-reduced forms changes across substrates. On poor, sandy substrates of arid environments, body shapes with longer hindlimbs may be more efficient for locomotion in a granular fluid (i.e. sand) and exploit the air–substrate interface than complete limblessness. On richer, more humid substrates, such morphology is rare, indicating that navigating cluttered substrates selects for more equal and shorter limb lengths.Marco Camaiti, Alistair R. Evans, Christy A. Hipsley, Mark N. Hutchinson, Shai Meiri, Rodolfo de Oliveira Anderson, Alex Slavenko, David G. Chappl

Wavelets and graph C∗C^*-algebras

Here we give an overview on the connection between wavelet theory and representation theory for graph $C^{\ast}$-algebras, including the higher-rank graph $C^*$-algebras of A. Kumjian and D. Pask. Many authors have studied different aspects of this connection over the last 20 years, and we begin this paper with a survey of the known results. We then discuss several new ways to generalize these results and obtain wavelets associated to representations of higher-rank graphs. In \cite{FGKP}, we introduced the "cubical wavelets" associated to a higher-rank graph. Here, we generalize this construction to build wavelets of arbitrary shapes. We also present a different but related construction of wavelets associated to a higher-rank graph, which we anticipate will have applications to traffic analysis on networks. Finally, we generalize the spectral graph wavelets of \cite{hammond} to higher-rank graphs, giving a third family of wavelets associated to higher-rank graphs

Epidemiological, clinical and genetic aspects of adult onset isolated focal dystonia in Ireland

Background: Adult onset idiopathic isolated focal dystonia presents with a number of phenotypes. Reported prevalence rates vary considerably; well-characterized cohorts are important to our understanding of this disorder. Aim: To perform a nationwide epidemiological study of adult onset idiopathic isolated focal dystonia in the Republic of Ireland. Methods: Patients with adult onset idiopathic isolated focal dystonia were recruited from multiple sources. Diagnosis was based on assessment by a neurologist with an expertise in movement disorders. When consent was obtained, a number of clinical features including family history were assessed. Results: On the prevalence date there were 592 individuals in Ireland with adult onset idiopathic isolated focal dystonia, a point prevalence of 17.8 per 100 000 (95% confidence interval 16.4-19.2). Phenotype numbers were cervical dystonia 410 (69.2%), blepharospasm 102 (17.2%), focal hand dystonia 39 (6.6%), spasmodic dysphonia 18 (3.0%), musician\u27s dystonia 17 (2.9%) and oromandibular dystonia six (1.0%). Sixty-two (16.5%) of 375 consenting index cases had a relative with clinically confirmed adult onset idiopathic isolated focal dystonia (18 multiplex and 24 duplex families). Marked variations in the proportions of patients with tremor, segmental spread, sensory tricks, pain and psychiatric symptoms by phenotype were documented. Conclusions: The prevalence of adult onset idiopathic isolated focal dystonia in Ireland is higher than that recorded in many similar service-based epidemiological studies but is still likely to be an underestimate. The low proportion of individuals with blepharospasm may reflect reduced environmental exposure to sunlight in Ireland. This study will serve as a resource for international comparative studies of environmental and genetic factors in the pathogenesis of the disorder

Natural Orbitals and BEC in traps, a diffusion Monte Carlo analysis

We investigate the properties of hard core Bosons in harmonic traps over a wide range of densities. Bose-Einstein condensation is formulated using the one-body Density Matrix (OBDM) which is equally valid at low and high densities. The OBDM is calculated using diffusion Monte Carlo methods and it is diagonalized to obtain the "natural" single particle orbitals and their occupation, including the condensate fraction. At low Boson density, $na^3 < 10^{-5}$, where $n = N/V$ and $a$ is the hard core diameter, the condensate is localized at the center of the trap. As $na^3$ increases, the condensate moves to the edges of the trap. At high density it is localized at the edges of the trap. At $na^3 \leq 10^{-4}$ the Gross-Pitaevskii theory of the condensate describes the whole system within 1%. At $na^3 \approx 10^{-3}$ corrections are 3% to the GP energy but 30% to the Bogoliubov prediction of the condensate depletion. At $na^3 \gtrsim 10^{-2}$, mean field theory fails. At $na^3 \gtrsim 0.1$, the Bosons behave more like a liquid $^4$He droplet than a trapped Boson gas.Comment: 13 pages, 14 figures, submitted Phys. Rev.