52 research outputs found

    Instantons for particles joined by strings in three dimensional gravity

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    We study the instantons describing the production of particles at the ends of codimension-one objects (strings and struts) in (2  +  1)-dimensional Minkowski and de Sitter spaces. A Minkowskian background allows only for systems with vanishing total mass, so that either negative mass particles or negative tension struts are required. On a de Sitter background, on the other hand, we find processes describing the production of string/particle systems with no negative energies involved. We also compute the probabilities of creating and of breaking an infinite cosmic string in de Sitter space. We perform our analysis of the system in de Sitter space employing a generalization of the toroidal coordinate system to the three-sphere

    Prevalence of treatment-resistant hypertension after considering pseudo-resistance and morbidity: a cross-sectional study in Irish primary care

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    peer-reviewedBackground To confirm treatment-resistant hypertension (TRH), ambulatory blood pressure measurement (ABPM) must exclude white-coat hypertension (WCH), three or more medications should be prescribed at the optimal doses tolerated, and non-adherence and lifestyle should be examined. Most previous studies have not adequately considered pseudo-resistance and merely provide an apparent TRH (aTRH) prevalence figure. Aim To conduct a cross-sectional study of the prevalence of aTRH in general practice, and then consider pseudo-resistance and morbidity. Design and setting With support, 16 practices ran an anatomical therapeutic chemical (ATC) drug search, identifying patients on any possible hypertensive medications, and then a search of individual patients' electronic records took place. Method ABPM was used to rule out WCH. The World Health Organization-defined daily dosing guidelines determined adequate dosing. Adherence was defined as whether patients requested nine or more repeat monthly prescriptions within the past year. Results Sixteen practices participated (n = 50 172), and 646 patients had aTRH. Dosing was adequate in 19% of patients, 84% were adherent to medications, as defined by prescription refill, and 43% had ever had an ABPM. Using a BP cut-off of 140/90 mmHg, the prevalence of aTRH was 9% (95% confidence interval [CI] = 9.0 to 10.0). Consideration of pseudo-resistance further reduced prevalence rates to 3% (95% CI = 3.0 to 4.0). Conclusion Reviewing individual patient records results in a lower estimate of prevalence of TRH than has been previously reported. Further consideration for individual patients of pseudo-resistance additionally lowers these estimates, and may be all that is required for management in the vast majority of cases.PUBLISHEDpeer-reviewe

    (Digital Presentation) Optimization of MIM Rectifiers for Terahertz Rectennas

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    Metal-Insulator-Metal (MIM) rectifiers comprising thin films of Al2O3, ZnO, NiO and Nb2O5 and metal configurations of Au/Au, Au/Zn and AuCr/AuCr, have been fabricated using atomic layer deposition and radio-frequency sputtering. The effect of device area scaling from 104 µm2 to 1 µm2 on rectification properties, in particular zero-bias dynamic resistance (R0) and zero-bias responsivity (β0) has been studied and found to be of critical importance in improving diode coupling efficiency. A significant increase of current has been found for Au/3.3 nm ZnO/Au diode when compared to the reference Au/3 nm Al2O3/Au diode, that resulted in obtaining the lowest R0 of 540 W for a device area of 104 µm2. The best performing device is found to be 1 µm2 AuCr/6.77 nm NiO/AuCr featuring (R0, b0) = (461 kW, 0.76 A/W) and a coupling efficiency of 1.5 ´ 10-5 %.</jats:p

    epiCaPture: a urine DNA methylation test for early detection of aggressive prostate cancer

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    Purpose Liquid biopsies that noninvasively detect molecular correlates of aggressive prostate cancer (PCa) could be used to triage patients, reducing the burdens of unnecessary invasive prostate biopsy and enabling early detection of high-risk disease. DNA hypermethylation is among the earliest and most frequent aberrations in PCa. We investigated the accuracy of a six-gene DNA methylation panel (Epigenetic Cancer of the Prostate Test in Urine [epiCaPture]) at detecting PCa, high-grade (Gleason score greater than or equal to 8) and high-risk (D'Amico and Cancer of the Prostate Risk Assessment] PCa from urine. Patients and Methods Prognostic utility of epiCaPture genes was first validated in two independent prostate tissue cohorts. epiCaPture was assessed in a multicenter prospective study of 463 men undergoing prostate biopsy. epiCaPture was performed by quantitative methylation-specific polymerase chain reaction in DNA isolated from prebiopsy urine sediments and evaluated by receiver operating characteristic and decision curves (clinical benefit). The epiCaPture score was developed and validated on a two thirds training set to one third test set. Results Higher methylation of epiCaPture genes was significantly associated with increasing aggressiveness in PCa tissues. In urine, area under the receiver operating characteristic curve was 0.64, 0.86, and 0.83 for detecting PCa, high-grade PCa, and highrisk PCa, respectively. Decision curves revealed a net benefit across relevant threshold probabilities. Independent analysis of two epiCaPture genes in the same clinical cohort provided analytical validation. Parallel epiCaPture analysis in urine and matched biopsy cores showed added value of a liquid biopsy. Conclusion epiCaPture is a urine DNA methylation test for high-risk PCa. Its tumor specificity out-performs that of prostate-specific antigen (greater than 3 ng/mL). Used as an adjunct to prostate-specific antigen, epiCaPture could aid patient stratification to determine need for biopsy

    Quantification of training load during one-, two- and three-game week schedules in professional soccer players from the English Premier League: implications for carbohydrate periodisation.

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    Muscle glycogen is the predominant energy source for soccer match play, though its importance for soccer training (where lower loads are observed) is not well known. In an attempt to better inform carbohydrate (CHO) guidelines, we quantified training load in English Premier League soccer players (n = 12) during a one-, two- and three-game week schedule (weekly training frequency was four, four and two, respectively). In a one-game week, training load was progressively reduced (P 14.4 km · h(-1) (14%, 18% and 23% in the one-, two- and three-game weeks, respectively). Considering that high CHO availability improves physical match performance but high CHO availability attenuates molecular pathways regulating training adaptation (especially considering the low daily customary loads reported here, e.g., 3-5 km per day), we suggest daily CHO intake should be periodised according to weekly training and match schedules

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    Genomic assessment of quarantine measures to prevent SARS-CoV-2 importation and transmission

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    Mitigation of SARS-CoV-2 transmission from international travel is a priority. We evaluated the effectiveness of travellers being required to quarantine for 14-days on return to England in Summer 2020. We identified 4,207 travel-related SARS-CoV-2 cases and their contacts, and identified 827 associated SARS-CoV-2 genomes. Overall, quarantine was associated with a lower rate of contacts, and the impact of quarantine was greatest in the 16–20 age-group. 186 SARS-CoV-2 genomes were sufficiently unique to identify travel-related clusters. Fewer genomically-linked cases were observed for index cases who returned from countries with quarantine requirement compared to countries with no quarantine requirement. This difference was explained by fewer importation events per identified genome for these cases, as opposed to fewer onward contacts per case. Overall, our study demonstrates that a 14-day quarantine period reduces, but does not completely eliminate, the onward transmission of imported cases, mainly by dissuading travel to countries with a quarantine requirement

    Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

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    AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p

    How might the Pres-Lam structural system be aesthetically refined in order to both impart a sense of safety to the users of such a building as well as express its structural function?

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    The Pres-Lam structural system has been applied in a mere few buildings currently, fewer still express the structural system in any meaningful way. If this relatively new system is to be more widely acknowledged and revered, we must explore ways in which a built example may effectively communicate the structural actions of the system as well as express the safety its inhabitants would be granted with regards to seismic activity and post-disaster habitability. It is this industry attitude towards structural expression, specifically in that of Pres-Lam, that is expressed in the working title, Project Ethos. Analysis of the structural function of Pres-Lam reveals the most feasible aspects of the system for expression to the user. Rocking and re-centering motion of the engineered timber shear walls are made possible by the internal post-tensioning cables as well as external mild steel dissipaters that may be replaced after acting sacrificially in a seismic event. Further to this, historical influence is taken from the architectural styles of High-Tech Architecture as well as Deconstructivism. The first two mid-rise buildings in New Zealand to explore this system in a wider sense give precedence for the attitudes taken towards the structural expression of Pres-lam. The first example, NMIT’s Arts and Media building, shows a level of internal structural expression aimed at communicating the raw detailing technicalities to industry professionals, while the second example, the Carterton Events Centre, makes critical use of Pres-Lam to ensure post-disaster habitability but makes little attempt to express the structural system in any meaningful way. This designed outcome proposes a multi-use mid-rise building in the earthquake affected town of Kaiapoi, and explores various methods of direct as well as indirect expression of the Pres-Lam structural system in order to communicate the inherent structural actions while imparting an aura of safety to the users
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