853 research outputs found

    Unbalanced quadriphase demodulator

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    A new and improved apparatus and method are described for demodulation of quaternary phase shift keyed (QPSK) data, particularly unbalanced QPSK. Phase adjustment of the output of a phase locked loop local oscillator is performed to reduce sensitivity to amplitude variations internal to the demodulator

    Monomorphic Ventricular Arrhythmias in Athletes.

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    Ventricular arrhythmias are challenging to manage in athletes with concern for an elevated risk of sudden cardiac death (SCD) during sports competition. Monomorphic ventricular arrhythmias (MMVA), while often benign in athletes with a structurally normal heart, are also associated with a unique subset of idiopathic and malignant substrates that must be clearly defined. A comprehensive evaluation for structural and/or electrical heart disease is required in order to exclude cardiac conditions that increase risk of SCD with exercise, such as hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy. Unique issues for physicians who manage this population include navigating athletes through the decision of whether they can safely continue their chosen sport. In the absence of structural heart disease, therapies such as radiofrequency catheter ablation are very effective for certain arrhythmias and may allow for return to competitive sports participation. In this comprehensive review, we summarise the recommendations for evaluating and managing athletes with MMVA

    From coinductive proofs to exact real arithmetic: theory and applications

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    Based on a new coinductive characterization of continuous functions we extract certified programs for exact real number computation from constructive proofs. The extracted programs construct and combine exact real number algorithms with respect to the binary signed digit representation of real numbers. The data type corresponding to the coinductive definition of continuous functions consists of finitely branching non-wellfounded trees describing when the algorithm writes and reads digits. We discuss several examples including the extraction of programs for polynomials up to degree two and the definite integral of continuous maps

    Limits to Poisson's ratio in isotropic materials

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    A long-standing question is why Poisson's ratio v nearly always exceeds 0.2 for isotropic materials, whereas classical elasticity predicts v to be between -1 to 1/2. We show that the roots of quadratic relations from classical elasticity divide v into three possible ranges: -1 < v <= 0, 0 <= v <= 1/5, and 1/5 <= v < 1/2. Since elastic properties are unique there can be only one valid set of roots, which must be 1/5 <= v < 1/2 for consistency with the behavior of real materials. Materials with Poisson's ratio outside of this range are rare, and tend to be either very hard (e.g., diamond, beryllium) or porous (e.g., auxetic foams); such substances have more complex behavior than can be described by classical elasticity. Thus, classical elasticity is inapplicable whenever v < 1/5, and the use of the equations from classical elasticity for such materials is inappropriate.Comment: Physical Review B, in pres

    Genome-wide single nucleotide polymorphism-based autozygosity mapping facilitates identification of mutations in consanguineous families with epidermolysis bullosa

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    Autozygosity mapping (AM) is a technique utilised for mapping homozygous autosomal recessive (AR) traits and facilitation of genetic diagnosis. We investigated the utility of AM for the molecular diagnosis of heterogeneous AR disorders, using epidermolysis bullosa (EB) as a paradigm. We applied this technique to a cohort of 46 distinct EB families using both short tandem repeat (STR) and genome-wide single nucleotide polymorphism (SNP) array-based AM to guide targeted Sanger sequencing of EB candidate genes. Initially, 39 of the 46 cases were diagnosed with homozygous mutations using this method. Independently, 26 cases, including the seven initially unresolved cases, were analysed with an EB-targeted next-generation sequencing (NGS) panel. NGS identified mutations in five additional cases, initially undiagnosed due to the presence of compound heterozygosity, deep intronic mutations or runs of homozygosity below the set threshold of 2 Mb, for a total yield of 44 of 46 cases (95.7) diagnosed genetically. © 2018 John Wiley & Sons Ltd

    Association Analysis of Type 2 Diabetes Loci in Type 1 Diabetes

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    OBJECTIVE—To search for a possible association of type 1 diabetes with 10 validated type 2 diabetes loci, i.e., PPARG, KCNJ11, WFS1, HNF1B, IDE/HHEX, SLC30A8, CDKAL1, CDKN2A/B, IGF2BP2, and FTO/RPGRIP1L

    Limits to Poisson's ratio in isotropic materials - general result for arbitrary deformation

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    The lower bound usually cited for Poisson's ratio {\nu} is -1, derived from the relationship between {\nu} and the bulk and shear moduli. From consideration of the longitudinal and biaxial moduli, we recently determined that the lower bound on {\nu} for isotropic materials is actually 1/5, a value also consistent with experimental measurements on real materials. Herein we generalize this result, first by analyzing expressions for {\nu} in terms of six common elastic constants, and then by considering arbitrary strains. The results corroborate the prior finding that 1/5 <= {\nu} for linear elasticity to be applicable.Comment: 15 pages, 3 figures, 1 tabl

    "It's what midwifery is all about": Western Australian midwives' experiences of being 'with woman' during labour and birth in the known midwife model

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    Background: The phenomenon of being 'with woman' is fundamental to midwifery as it underpins its philosophy, relationships and practices. There is an identified gap in knowledge around the 'with woman' phenomenon from the perspective of midwives providing care in a variety of contexts. As such, the aim of this study was to explore the experiences of being 'with woman' during labour and birth from the perspective of midwives' working in a model where care is provided by a known midwife. Methods: A descriptive phenomenological design was employed with ten midwives working in a 'known midwife' model who described their experiences of being 'with woman' during labour and birth. The method was informed by Husserlian philosophy which seeks to explore the same phenomenon through rich descriptions by individuals revealing commonalities of the experience. Results: Five themes emerged 1) Building relationships; 2) Woman centred care; 3) Impact on the midwife; 4) Impact on the woman; and 5) Challenges in the Known Midwife model. Midwives emphasised the importance of trusting relationships while being 'with woman', confirming that this relationship extends beyond the woman - midwife relationship to include the woman's support people and family. Being 'with woman' during labour and birth in the context of the relationship facilitates woman-centred care. Being 'with woman' influences midwives, and, it is noted, the women that midwives are working with. Finally, challenges that impact being 'with woman' in the known midwife model are shared by midwives. Conclusions: Findings offer valuable insight into midwives' experiences of being 'with woman' in the context of models that provide care by a known midwife. In this model, the trusting relationship is the conduit for being 'with woman' which influences the midwife, the profession of midwifery, as well as women and their families. Descriptions of challenges to being 'with woman' provide opportunities for professional development and service review. Rich descriptions from the unique voice of midwives, provided insight into the applied practices of being 'with woman' in a known midwife model which adds important knowledge concerning a phenomenon so deeply embedded in the philosophy and practices of the profession of midwifery
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