Symbolic Computation of Quantities Associated With Time-Periodic Dynamical Systems 1

Many dynamical systems can be modeled by a set of linear/nonlinear ordinary differential equations with periodic time-varying coefficients. The state transition matrix (STM) Uðt; aÞ, associated with the linear part of the equation, can be expressed in terms of the periodic Lyapunov-Floqu et (L-F) transformation matrix Qðt; aÞ and a time-invariant matrix RðaÞ containing a set of symbolic system parameters a: Computation of Qðt; aÞ and RðaÞ in symbolic form as a function of a is of paramount importance in stability, bifurcation analysis, and control system design. In earlier studies, since Qðt; aÞ and RðaÞ were available only in numerical forms, general results for parameter unfolding and control system design could not be obtained in the entire parameter space. In 2009, an attempt was made b

A detective duo of apatite and zircon geochronology for East Avalonia, Johnston Complex, Wales

Published online: March 30, 2023. OnlinePublThe Johnston Complex represents a rare inlier of the Neoproterozoic basement of southern Britain and offers a window into the tectonomagmatic regime of East Avalonia during the assembly of Gondwana. This work presents in-situ zircon (U-Pb, Lu-Hf), apatite (U-Pb), and trace element chemistry for both minerals from the Complex. Zircon and apatite yield a coeval crystallisation age of 570 ± 3 Ma, and a minor antecrystic zircon core component is identified at 615 ± 11 Ma. Zircon Lu-Hf data imply a broadly chondritic source, comparable to Nd data from East Avalonia, and TDM 2 model ages of ca. 1.5 Ga indicate source extraction during the Mesoproterozoic. Zircon trace element chemistry is consistent with an ensialic calcalkaline continental arc setting and demonstrates that magmatism was ongoing prior to terrane dispersal at 570 Ma. Apatite trace element chemistry implies a sedimentary component within the melt consistent with voluminous S-type granite production during the formation of Gondwana. The similarity of ɛHf and geochemistry between both zircon age populations suggest derivation from a uniform source that did not undergo significant modification between 615 – 570 Ma. Time-constrained apatite-zircon chemistry addresses complexities in dating S-type granitoids (zircon inheritance) and permits inferences on post-magmatic thermal histories.Anthony J.I. Clarke, Christopher L. Kirkland, Stijn Glori

The Glenburgh Orogeny as a record of Paleoproterozoic continent-continent collision

The Gascoyne Province lies at the western end of the Capricorn Orogen, and includes a range of Paleoproterozoic gneisses and metasedimentary basins, known as the Glenburgh Terrane, that are exotic to both the Yilgarn and Pilbara Cratons. Here we present sensitive high-resolution ion microprobe (SHRIMP) U–Pb ages for a variety of detrital zircons and metamorphic zircon and monazite from several of these pre-collisional siliciclastic basins that were deformed and metamorphosed at high metamorphic grade during the Glenburgh Orogeny, when the Yilgarn Craton collided with a previously assembled Pilbara Craton – Glenburgh Terrane. The precursors to the Moogie Metamorphics were deposited sometime between 2240 and 2125 Ma in either a foreland basin to the Ophthalmian Orogeny, or a retro-arc that formed during the collision of the Glenburgh Terrane with the Pilbara Craton. The Quartpot Pelite of the Camel Hills Metamorphics was deposited between 2000 Ma and 1985 Ma as a fore-arc deposit to the Dalgaringa continental margin arc. The Petter Calc-silicate of the Camel Hills Metamorphics was deposited sometime between 2610 and 1965 Ma as part of the Yilgarn Craton passive margin. Metamorphic zircon and monazite ages indicate that continental collision and high-grade metamorphism during the Glenburgh Orogeny (D2g) took place between 1965 Ma and 1950 Ma

Influenza Virus Transmission from Horses to Dogs, Australia

During the 2007 equine influenza outbreak in Australia, respiratory disease in dogs in close contact with infected horses was noted; influenza (H3N8) virus infection was confirmed. Nucleotide sequence of the virus from dogs was identical to that from horses. No evidence of dog-to-dog transmission or virus persistence in dogs was found

Predictors of transitions in frailty severity and mortality among people aging with HIV.

BACKGROUND: People aging with HIV show variable health trajectories. Our objective was to identify longitudinal predictors of frailty severity and mortality among a group aging with HIV. METHODS: Exploratory analyses employing a multistate transition model, with data from the prospective Modena HIV Metabolic Clinic Cohort Study, based in Northern Italy, begun in 2004. Participants were followed over four years from their first available visit. We included all 963 participants (mean age 46.8±7.1; 29% female; 89% undetectable HIV viral load; median current CD4 count 549, IQR 405–720; nadir CD4 count 180, 81–280) with four-year data. Frailty was quantified using a 31-item frailty index. Outcomes were frailty index score or mortality at four-year follow-up. Candidate predictor variables were baseline frailty index score, demographic (age, sex), HIV-disease related (undetectable HIV viral load, current CD4+ T-cell count, nadir CD4 count, duration of HIV infection, and duration of antiretroviral therapy [ARV] exposure), and behavioral factors (smoking, injection drug use (IDU), and hepatitis C virus co-infection). RESULTS: Four-year mortality was 3.0% (n = 29). In multivariable analyses, independent predictors of frailty index at follow-up were baseline frailty index (RR 1.06, 95% CI 1.05–1.07), female sex (RR 0.93, 95% CI 0.87–0.98), nadir CD4 cell count (RR 0.96, 95% CI 0.93–0.99), duration of HIV infection (RR 1.06, 95% CI 1.01–1.12), duration of ARV exposure (RR 1.08, 95% CI 1.02–1.14), and smoking pack-years (1.03, 1.01–1.05). Independent predictors of mortality were baseline frailty index (OR 1.19, 1.02–1.38), current CD4 count (0.34, 0.20–0.60), and IDU (2.89, 1.30–6.42). CONCLUSIONS: Demographic, HIV-disease related, and social and behavioral factors appear to confer risk for changes in frailty severity and mortality among people aging with HIV

Role of corticosteroids in Functional Endoscopic Sinus Surgery - a systematic review and meta-analysis

Background: The aim of our study is to systematically review the existing evidence on the role of corticosteroids in patients undergoing functional endoscopic sinus surgery (FESS).  Methodology: Systematic search of MEDLINE (1950- 2014), EMBASE (1980-2014), metaRegister, Cochrane Library and ISI conference proceedings was carried out.  Results: Eighteen randomised controlled trials with 1309 patients were included. Use of local and/or systemic corticosteroids with FESS was reported in four categories; operative, anaesthesia related, post-operative outcomes and risk of recurrence. Metaanalysis for operative outcomes demonstrated that, mean operative time (MD -10.70 minutes; 95% CI -15.86, -5.55; P <0.0001) and mean estimated blood loss (MD -28.32 mls; 95% CI -40.93, -15.72; P <0.0001) was significantly lower; and surgical field quality (MD -0.81; 95% CI -1.32, -0.30; P = 0.002) was significantly better in corticosteroid group. Meta-analysis showed that post-operative endoscopic scores (SMD -0.39; 95% CI -0.60, -0.17; P = 0.0004) were significantly better in corticosteroid group compared to no corticosteroid group. There was no increase in risk of sinusitis (RR 0.64; 95% CI 0.32, 1.30; P = 0.22) between use of corticosteroids and no corticosteroids; There was no significant difference in recurrence risk of chronic rhinosinusitis (CRS) in mixed population studies (RR 0.77; 95% CI 0.35, 1.70; P = 0.52) between the two groups but analysis of studies reporting on chronic rhinosinusitis with nasal polyps (CRSwNP) (RR 0.64;95% CI 0.45,0.91;P=0.01) showed significant difference in favour of the corticosteroid group.  Conclusion: Pre-operative use of local and/or systemic corticosteroids in FESS, results in significantly reduced blood loss, shorter operative time and improved surgical field quality. Studies are limited on the intra-operative use of corticosteroids to reduce postoperative pain. Postoperative corticosteroids improve postoperative endoscopic scores in CRS and recurrence rates in cases of CRSwNP

Automated carotid endarterectomy surgery using a low cost remodelled industrial robotic arm

No description supplie