Rational structural solutions for triangular trusses

Wooden rafter structures have undoubted advantages, which determine their wide application. The object of the study is triangular rafter structures. The purpose of the research is to find the dependence of force values in the elements of the studied structure on the magnitude of its lifting boom. The calculation of a triangular truss using the Maxwell - Cremona diagram is presented. The efficiency of the proposed method was estimated on the basis of a study of the structure of a wooden truss of the “scissors” type. The following pattern has been established: the change in the coordinates of the points (abscissas) of the force diagram is inversely proportional to the change in f . It is determined the area of rational values of the lift (roof slope) at which the values of internal forces tend to a minimum. It was revealed that the values of force increments in the truss elements at each step increase from 27% to 2 times when the roof slope de-creases. Based on the graphical analysis of the obtained data the range of effective values of the roof slope at which the forces in the elements of the truss take minimum values was found. Using a graphic method of determining the forces, it is possible to check variants of the roof slope in the search for a rational solution of the “scissor” type truss structure. It follows that the proposed method contributes to the choice of the most economical structural solutions

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Generation of Error Indicators for Partial Differential Equations by Machine Learning Methods

Computer simulation methods for models based on partial differential equations usually apply adaptive strategies that generate sequences of approximations for consequently refined meshes. In this process, error indicators play a crucial role because a new (refined) mesh is created by analysis of an approximate solution computed for the previous (coarser) mesh. Different error indicators exploit various analytical and heuristic arguments. The main goal of this paper is to show that effective indicators of approximation errors can be created by machine learning methods and presented by relatively simple networks. We use the “supervised learning” conception where sequences of teaching examples are constructed due to earlier developed tools of a posteriori error analysis known as “functional type error majorants”. Insensitivity to specific features of approximations is an important property of error majorants, which allows us to generate arbitrarily long series of diverse training examples without restrictions on the type of approximate solutions. These new (network) error indicators are compared with known indicators. The results show that after a proper machine learning procedure, we obtain a network with the same (or even better) quality of error indication level as the most efficient indicators used in classical computer simulation methods. The final trained network is approximately as effective as the gradient averaging error indicator, but has an important advantage because it is valid for a much wider set of approximate solutions.peerReviewe

STUDY OF THE LED REMOVABLE NOZZLE ON THE REFLECTOR OF AN ELECTRON TOTAL STATION

The article presents the results of a study of a removable LED nozzle on the reflector of an electronic total station. A description of the LED removable nozzle on the reflector of the electronic total station is made. The results of measurements of the runtime of pointing the device at the reflector at night, at various distances and in bad weather conditions (snowfall) are presented. A comparison between the results of studies with different backlight modes of the total station reflector is made. Models of reflectors with pulsed illumination manufactured by various instrument-making enterprises and their cost are given. Based on the results of the studies and analysis, conclusions on the use of a removable LED nozzle for performing geodetic measurements in the production of engineering and geodetic surveys and other types of geodetic works are drawn. The advantages and disadvantages of the LED removable nozzle are given.</jats:p

A posteriori error control for Maxwell and elliptic type problems

In this paper, we discuss a posteriori estimates for the Maxwell type boundary-value problem. The estimates are derived by transformations of integral identities that define the generalized solution and are valid for any conforming approximation of the exact solution. It is proved analytically and confirmed numerically that the estimates indeed provide a computable and guaranteed bound of approximation errors. Also, it is shown that the estimates imply robust error indicators that represent the distribution of local (inter-element) errors measured in terms of different norms.peerReviewe

Low-grade inflammation in prognosis in patients undergoing coronary artery bypass grafting: The importance of neutrophil-to-lymphocyte ratio and growth differentiation factor 15

Background — Predicting major adverse cardiovascular events (MACE) after coronary interventions is an urgent and important mission. Subclinical inflammation markers are increasingly investigated for this purpose. Objective: To determine the role of neutrophil-to-lymphocyte ratio (NLR) and growth differentiation factor 15 (GDF-15) in predicting MACE in patients after coronary artery bypass grafting (CABG). Methods — This prospective observational study included 80 patients with coronary artery disease who underwent CABG and were followed for at least a year. In prospective follow-up, the composite endpoint (MACE) constituted 27.5% (22 events). Results — GDF-15 and NLR values were similar in the groups with and without MACE. ROC analysis showed low AUC for NLR (AUC=0.566, p=0.363) and GDF-15 (AUC=0.621, p=0.096). The value of the GDF-15×NLR product was calculated. The median was 3,108.05 (2,069; 4,145) for patients without MACE and 4,108.8 (2,779.4; 5,890.5) for patients with MACE (p=0.010). This association remained after adjustment for gender, age, diabetes mellitus, and left ventricular ejection fraction. Conclusion — The product, NLR×GDF-15, is associated with adverse cardiovascular events in patients after CABG

Hard Numbers: Open Consumer Price Database

We document a new source of consumer price microdata. The new database allows researchers studying consumer price behaviour to access current and granular raw statistical observations. The range of observed prices fully covers goods and services of the Rosstat’s CPI sample and extends beyond it. In this paper, we pursue two objectives. First, we describe the data collection mechanism, data structure, and their access protocols, as well provide four complete illustrations of their application using open API: i) training machine models of product classification based on text labels, ii) real-time tracking of product prices, iii) estimating hedonic regressions for product groups, and iv) calculating arbitrary analytical price indices. Second, we share a set of basic skills and technologies for the benefit of researchers interested in creating their own sources of alternative data.</jats:p

Community-Based View on Diagnostic Imaging at the End of COVID-19 Pandemic: Online Survey-Assisted Study

(1) Background: An online survey-based observational cross-sectional study aimed at elucidating the experience and attitudes of an unstructured population regarding diagnostic imaging. (2) Methods: Invitations to participate were distributed using mixed-mode design to deidentified residents aged 18 years and older. Main outcome measures included morbidity structure and incidence of diagnostic imaging administrations. (3) Results: Respondents (n = 1069) aged 44.3 &plusmn; 14.4 years; 32.8% suffered from cardiovascular diseases (CVD); 9.5% had chronic respiratory pathology; 28.9% considered themselves healthy. Respondents with COVID-19 history (49.7%) reported higher rates of computed tomography (CT) (p &lt; 0.0001), magnetic resonance imaging (MRI) (p &lt; 0.001), and ultrasound (p &lt; 0.05). COVID-19 history in CVD respondents shifted imaging administrations towards CT and MRI (p &lt; 0.05). Every tenth respondent received MRI, CT, and ultrasound on a paid basis; 29.0% could not pay for diagnostic procedures; 13.1% reported unavailable MRI. Professional status significantly affected the pattern of diagnostic modalities (p &lt; 0.05). MRI and CT availability differed between respondents in urban and rural areas (p &lt; 0.0001). History of technogenic events predisposed responders to overestimate diagnostic value of fluorography (p &lt; 0.05). (4) Conclusions: Preparedness to future pandemics requires the development of community-based outreach programs focusing on people&rsquo;s awareness regarding medical imaging safety and diagnostic value