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Whole-genome sequencing (WGS) information has played a crucial role in the SARS-CoV-2 (COVID-19) pandemic by providing evidence about variants to inform public health policy. The purpose of this study was to assess the representativeness of sequenced cases compared with all COVID-19 cases in England, between March 2020 and August 2021, by demographic and socio-economic characteristics, to evaluate the representativeness and utility of these data in epidemiological analyses. To achieve this, polymerase chain reaction (PCR)-confirmed COVID-19 cases were extracted from the national laboratory system and linked with WGS data. During the study period, over 10% of COVID-19 cases in England had WGS data available for epidemiological analysis. With sequencing capacity increasing throughout the period, sequencing representativeness compared to all reported COVID-19 cases increased over time, allowing for valuable epidemiological analyses using demographic and socio-economic characteristics, particularly during periods with emerging novel SARS-CoV-2 variants. This study demonstrates the comprehensiveness of England’s sequencing throughout the COVID-19 pandemic, rapidly detecting variants of concern, and enabling representative epidemiological analyses to inform policy.
Realizing packaged state-of-the-art performance of monolithic microwave integrated circuits (MMICs) operating at millimeter wavelengths presents significant challenges in terms of electrical interface circuitry and physical construction. For instance, even with the aid of modern electromagnetic simulation tools, modeling the interaction between the MMIC and its package embedding circuit can lack the necessary precision to achieve optimum device performance. Physical implementation also introduces inaccuracies and requires iterative interface component substitution that can produce variable results, is invasive and risks damaging the MMIC. This paper describes a novel method for in situ optimization of packaged millimeter-wave devices using a pulsed ultraviolet laser to remove pre-selected areas of interface circuit metallization. The method was successfully demonstrated through the optimization of a 183 GHz low noise amplifier destined for use on the MetOp-SG meteorological satellite series. An improvement in amplifier output return loss from an average of 12.9 dB to 22.7 dB was achieved across an operational frequency range of 175–191 GHz and the improved circuit reproduced. We believe that our in situ tuning technique can be applied more widely to planar millimeter-wave interface circuits that are critical in achieving optimum device performance.
A major goal of Gardner, Ryan, and Snoeyink (2018) was to determine what steps are needed moving forward in examining gender representation in industrial and organizational (I-O) psychology. Specifically, on the topic of pay differences, we highlight that gender differences in pay are in part due to differences in negotiation behaviors and/or experiences. Prior research demonstrates that female negotiators receive greater backlash than male negotiators—a possible explanation to why men tend to negotiate more often and more successfully than women (Bowles, Babcock, & Lai, 2007). Based on this evidence, one next step in moving forward should involve providing resources and knowledge to improve negotiation skills and practices specifically aimed at eliminating differences between women and men in both propensity to negotiate and the evaluation/consequences of negotiating.
Poly(3,4-ethylenedioxythiophene) (PEDOT) is an organic conducting polymer that has been the focus of significant research over the last decade, in both energy and biological applications. Most commonly, PEDOT is doped by the artificial polymer polystyrene sulfonate due to the excellent electrical characteristics yielded by this pairing. The biopolymer dextran sulphate (DS) has been recently reported as a promising alternative to PEDOT:PSS for biological application, having electrical properties rivaling PEDOT:PSS, complimented by the potential bioactivity of the polysaccharide. In this work we compared chemical and electrochemical polymerisations of PEDOT:DS in terms of their impact on the electrical, morphological and biological properties of the resultant PEDOT:DS films. Post-growth cyclic voltammograms and UV-Vis analyses revealed comparable redox behaviour and absorbance profiles for the two synthesis approaches. Despite good intrinsic conductivity of particles, the addition of chemically produced PEDOT:DS did not markedly enhance the bulk conductivity of aqueous solutions due to the lack of interconnectivity between adjacent PEDOT:DS particles at achievable concentrations. Scanning electron microscopy revealed significantly greater roughness in films cast from chemically produced PEDOT:DS compared to electropolymerised samples, attributable to the formation of solution phase nanoparticles prior to casting. In cell studies with the L929 cell line, electrochemical polymerisation of PEDOT:DS afforded better integrity of resultant films for surface seeding, whilst chemically polymerised PEDOT:DS appeared to localised at the proliferating cells, suggesting possible applications in drug delivery.
This volume comprises the proceedings of the 1995 Cardiff symposium on sieve methods, exponential sums, and their applications in number theory. Included are contributions from many leading international figures in this area which encompasses the main branches of analytic number theory. In particular, many of the papers reflect the interaction between the different fields of sieve theory, Dirichlet series (including the Riemann Zeta-function), and exponential sums, whilst displaying the subtle interplay between the additive and multiplicative aspects of the subjects. The fundamental problems discussed include recent work on Waring's problem, primes in arithmetical progressions, Goldbach numbers in short intervals, the ABC conjecture, and the moments of the Riemann Zeta-function.
Let ‖x‖ denote the distance of x from the nearest integer. In 1948 H. Heilbronn proved [5] that for ε>0 and N>c1(ε) the inequality
holds for any real α. This result has since been generalised in many different directions, and we consider here extensions of the type: For ε>0, N>c2{ε, s) and a quadratic formQ(x1,…, xs) there exist integersn1,…,nsnot all zero with |n1|,…,|ns≦N and with
The authors sharpen a result of Baker and Harman (1995), showing that [x, x + x0.525] contains prime numbers for large x. An important step in the proof is the application of a theorem of Watt (1995) on a mean value containing the fourth power of the zeta function. 2000 Mathematical Subject Classification: 11N05.
Let $a_n$ be an increasing
sequence of positive reals with $a_n \rightarrow \infty$ as $n \rightarrow \infty$. Necessary and
sufficient conditions are obtained for each of the sequences $[\alpha a_n], [\alpha^{a_n}],
[{a_n}^{\alpha}]$ to take on infinitely many prime values for almost all $\alpha > \beta$. For
example, the sequence $[\alpha a_n]$ is infinitely often prime for almost all $\alpha > 0$ if and only
if there is a subsequence of the $a_n$, say $b_n$, with $b_{n+1} > b_n + 1$ and with the series $\sum
1/{b_n}$ divergent. Asymptotic formulae are obtained when the sequences considered are lacunary. An
earlier result of the author reduces the problem to estimating the measure of overlaps of certain
sets, and sieve methods are used to obtain the correct order upper bounds.
G. R. H. Greaves, University of Wales College of Cardiff,G. Harman, University of Wales College of Cardiff,M. N. Huxley, University of Wales College of Cardiff
Between the 17th and the 21st of July, 1995 a group of about fifty mathematicians gathered in Cardiff for the Symposium on Sieve Methods, Exponential Sums and their Applications in Number Theory. They exchanged lectures and informal discussions and posed problems in the broad subject area defined by the title of the Symposium. This volume of papers gives an account of work described at the Symposium. Certain articles include a description of work done after the Symposium closed, some of this being prompted by questions posed during the Symposium.
Many of the contributions involve connections between the additive and multiplicative sides of analytic number theory, an interplay which the Symposium had been planned both to reflect and to promote. The reader will find represented here most of the branches of this subject which, as this volume demonstrates, has its roots in antiquity with the Sieve of Eratosthenes, yet is currently vibrant and receiving fresh stimulus from such diverse topics as trace formulae and elliptic curves.
Many of the participants at the Symposium were supported by the Engineering and Physical Sciences Research Council of the U.K. Others were able to bring their own support with them. The administrative costs were underwritten by the London Mathematical Society. The organisers, who are also the editors of this volume, are grateful to all the sources of support which made the Symposium possible.
The papers in this volume have been refereed to the standards required by leading journals; we take this opportunity to thank the referees for their work.
G. R. H. Greaves, University of Wales College of Cardiff,G. Harman, University of Wales College of Cardiff,M. N. Huxley, University of Wales College of Cardiff
G. R. H. Greaves, University of Wales College of Cardiff,G. Harman, University of Wales College of Cardiff,M. N. Huxley, University of Wales College of Cardiff
G. R. H. Greaves, University of Wales College of Cardiff,G. Harman, University of Wales College of Cardiff,M. N. Huxley, University of Wales College of Cardiff
G. R. H. Greaves, University of Wales College of Cardiff,G. Harman, University of Wales College of Cardiff,M. N. Huxley, University of Wales College of Cardiff
G. R. H. Greaves, University of Wales College of Cardiff,G. Harman, University of Wales College of Cardiff,M. N. Huxley, University of Wales College of Cardiff
G. R. H. Greaves, University of Wales College of Cardiff,G. Harman, University of Wales College of Cardiff,M. N. Huxley, University of Wales College of Cardiff
The problem concerning the distribution of the fractional parts of the sequence ank (k an integer exceeding one) was first considered by Hardy and Littlewood [6] and Weyl [20] earlier this century. This work was developed, with the focus on small fractional parts of the sequence, by Vinogradov [17], Heilbronn [13] and Danicic [2] (see [1]). Recently Heath-Brown [12] has improved the unlocalized versions of these results for k ≥ 6 (a slightly stronger result than Heath-Brown's for K = 8 is given on page 24 of [8]. The method mentioned there can, after some numerical calculation, improve Heath-Brown's result for 8 ≤ k ≤ 20, but still stronger results have recently been obtained by Dr. T. D. Wooley). The cognate problem regarding the sequence apk, where p denotes a prime, has also received some attention. In this situation even the case k = 1 proves to be difficult (see [9] and [14]). The first results in this field were given by Vinogradov (see Chapter 11 of [19] for the case k = 1, [18] for k ≥ 2). For k = 2 the best result to date has been supplied by Ghosh [5], and for ≥, by Harman (Theorem 3 in [9], building on the work in [7] and [8]). In this paper we shall improve the known results for 2 ≤ k ≤ 12. For larger k, Theorem 3 in [8] is more efficient. The theorem we prove is as follows.
Let {α} denote the fractional part of the real number α. Write χ(x, y) = 1 for {x} < y and χ(x, y) = 0 otherwise. A real sequence (xn) is uniformly distributed (mod 1) if
Materials problems have always been a significant cause of wire bond failures in microelectronics. However, modern VLSI materials, processing, and packaging methods combined often result in new or masked versions of old failure mechanisms. This paper describes the classical Au-Al intermetallic compound problem as described by a new two-dimensional finite element diffusion model and demonstrates that diffusion in poor welds is more rapid than in bulk couples. Failures resulting from modern bonding material couples (e.g., Cu-Au, Al-Ag, etc.) can result in bond failures superficially resembling Au-Al type failures. Failures resulting from bonds made to contaminated gold electroplated films are described, and a new failure model resulting from hydrogen in these films is shown.
We denote by ∥…∥ the distance to the nearest integer. Let ε be an arbitrary positive number. Danicic(6) showed that for N > c1(s, ε) and a quadratic form Q(x1, …, xs) there exist integers n1, …, ns with