A weighted logarithmic barrier interior-point method for linearly constrained optimization

In this paper, a weighted logarithmic barrier interior-point method for solving the linearly convex constrained optimization problems is presented. Unlike the classical central-path, the barrier parameter associated with the per- turbed barrier problems, is not a scalar but is a weighted positive vector. This modi cation gives a theoretical exibility on its convergence and its numerical performance. In addition, this method is of a Newton descent direction and the computation of the step-size along this direction is based on a new e cient tech- nique called the tangent method. The practical e ciency of our approach is shown by giving some numerical results.

BEARING CAPACITY OF FOLDED PLATE FOUNDATIONS IN CLAY SOIL

The design of a foundation is inseparable from the type and strength of the soil, for example, clay soils have poor properties for structures due to their low bearing capacity. Therefore, it is necessary to modify the model of a foundation to increase its bearing capacity and one of the popular methods is the application of folded plate on a flat foundation with angles and flange lengths on both sides. Therefore, this research presented its application at different flange lengths of 0.5B, 0.75B, 1B, 1.25B, and 1.5B where B is the width of the flat plate and the results showed the bearing capacity of the folded plate was higher than the flat foundation. Moreover, an increment in the folded length led to a bigger ultimate load and smaller settlement but the ultimate load and settlement were observed to be almost constant at over 1B. This means the optimum variation where the flange length is equal to the foundation width is 1B and it was observed to have increased by 129.52 % using the Tangent Method and 148.4 7% with Butler Hoy Method. Meanwhile, the lowest settlement factor for the folded plate foundation was 0.22 with the highest bearing capacity of 61.19 kN/m2

Traveling Wave Solutions of a Four Dimensional Reaction-Diffusion Model for Porcine Reproductive and Respiratory Syndrome with Time Dependent Infection Rate

Porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive failure in sows and respiratory disease in piglets and growing pigs. The disease rapidly spreads in swine populations, making it a serious problem causing great financial losses to the swine industry. However, past mathematical models used to describe the spread of the disease have not yielded sufficient understanding of its spatial transmission. This work has been designed to investigate a mathematical model for the spread of PRRSV considering both time and spatial dimensions as well as the observed decline in infectiousness as time progresses. Moreover, our model incorporates into the dynamics the assumption that some members of the infected population may recover from the disease and become immune. Analytical solutions are derived by using the modified extended hyperbolic tangent method with the introduction of traveling wave coordinate. We also carry out a stability and phase analysis in order to obtain a clearer understanding of how PRRSV spreads spatially through time.

Geometric design of the limaçon-to-circular fluid processing machine

A limaçon machine is a rotary positive displacement device, in which the housing and rotor are constructed of limaçon of Pascal curves. Previous works have been published to investigate the working of these machines in two applications: gas expanders and compressors. This paper presents a theoretical investigation into the potential of modifying the rotor prole of the limaçon machines in order to simplify the machine's manufacturing process and to reduce production cost. The proposed modification will produce new characteristics for the housing-rotor interaction. An outcome that motivates the need to obtain new mathematical models to investigate the housing-rotor interference, and describe the volumetric relationships of the new machine. This paper sets out by introducing a background on the limaçon technology in a simple yet adequate fashion. The housing-rotor inference has been discussed from two different mathematical standpoints, i.e. the tangent method and the radial clearance method. The paper then introduces the volumetric relationship for the proposed modified machine and combines all the models produced in an optimisation endeavour to design the best machine for a given set of operating condition. Case studies of different fluid processing applications are considered to demonstrate the soundness of the proposed modifications and models. The outcome of this study confirms the validity of the proposed modification and its potential to produce a limaçon machine with favourable characteristics.

Abstract 14311: Qt Interval Correlation Between Telemetry and 12-lead Electrocardiogram

Introduction: QT prolongation is associated with increased risk of ventricular arrhythmias.As many patients with COVID19 may be started on QT prolonging drugs, measuring and monitoring QT is imperative to prevent fatal ventricular arrhythmias. However, we need to limit exposure of staff to patients with confirmed COVID19 and judiciously use personal protective equipment. Thus, it is important to find alternatives to doing frequent 12-lead ECGs. Hypothesis: We hypothesize that the QT interval measured from telemetry is similar to the QT interval on 12-lead ECG. Methods: Telemetry recordings and 12-lead ECGs were obtained from 15 patients at the same time and identical heart rates. Patients were from two different inpatient units with the same telemetry monitoring service. QT intervals were measured manually using calipers with the tangent method, excluding U waves. Telemetry recordings included lead I and II or a precordial lead. QT from telemetry was compared to the corresponding leads and to the longest QT on the 12-lead ECG. In cases of atrial fibrillation (AF), the QT from all the complexes was averaged. Results: Of 15 patients, 2 were in AF and 2 had RBBB. One patient had abnormal T-wave morphology and QT prolongation (abnormal repolarization). In all patients, QT intervals from the same leads as telemetry matched the QT measured from 12-lead. In 14 of 15 patients, telemetry QT matched the longest QT on the 12-lead ECG. However, in the patient with abnormal repolarization, maximum QT on 12-lead ECG was substantially longer than telemetry QT (Figure 1). Conclusion: When using the same lead, QT intervals were identical on telemetry and 12-lead ECG. However, in the patient with abnormal repolarization, the longest QT on 12-lead ECG was not represented on telemetry. In patients with abnormal repolarization on 12-lead ECG, we recommend serial 12-lead ECGs while on QT-prolonging drugs. Telemetry may suffice as a surrogate for 12-lead ECG to follow QT intervals in most patients.

Efficacy of Modified Cervical and Shoulder Retraction Exercise in Patients With Loss of Cervical Lordosis and Neck Pain

Objective To explore if the modified cervical and shoulder retraction exercise program restores cervical lordosis and reduces neck pain in patients with loss of cervical lordosis.Methods This study was a retrospective analysis of prospectively collected data. Eighty-three patients with loss of cervical lordosis were eligible. The eligible patients were trained to perform the modified cervical and shoulder retraction exercise program by a physiatrist, and were scheduled for a follow-up 6 to 8 weeks later to check the post-exercise pain intensity and lateral radiograph of the cervical spine in a comfortable position. The parameters of cervical alignment (4-line Cobb’s angle, posterior tangent method, and sagittal vertical axis) were measured from the lateral radiograph.Results Forty-seven patients were included. The mean age was 48.29±14.47 years. Cervical alignment and neck pain significantly improved after undergoing the modified cervical and shoulder retraction exercise program (p≤0.001). The upper cervical lordotic angle also significantly improved (p=0.001). In a subgroup analysis, which involved dividing the patients into two age groups (<50 years and ≥50 years), the change of the sagittal vertical axis was significantly greater in the <50 years group (p=0.021).Conclusion The modified cervical and shoulder retraction exercise program tends to improve cervical lordosis and neck pain in patients with loss of cervical lordosis.

QT-Zeit – Was fange ich eigentlich damit an?

The assessment of the QT interval has been an integral part of ECG interpretation since the first descriptions of long QT syndrome by Wolff in 1950 and by Jervell and Lange-Nielsen in 1957. The correct measurement of the QT interval as well as a correct interpretation of the causes and of the clinical consequences of a QT prolongation, however, may be difficult even for trained internists and cardiologists. In this review, we give an overview on physiological determinants of cardiac repolarization, its marker in the surface ECG – the QT interval –, methods to correctly assess QT interval duration, causes for pathologically prolonged QT intervals, and resulting clinical consequences. A correct measurement of the QT interval should be performed by using the „tangent method“, excluding possible U waves. A heart rate correction formula should be employed to determine the heart rate corrected QT interval (QTc).Many factors, which may prolong the QT interval, should be checked whenever a QTc prolongation is observed. These include drugs, electrolyte imbalances, hormonal influence, and comorbidities. The correct management of a patient with (genetically determined) LQTS starts with a risk stratification based on genotype, ECG phenotype, clinical history, age, sex, concomitant diseases, drug therapies, and family history for syncope or sudden cardiac death. The therapeutic approaches for LQTS are multimodal. Prevention is the basis of the therapy and includes avoiding known risk factors / and potentially QT-prolonging drugs, and a pharmacological treatment with non-selective beta blockers. According to the risk profile and to the patient’s lifestyle the implantation of an ICD or a pacemaker should be considered.