A framework for habitat monitoring and climate change modelling: construction and validation of the Environmental Stratification of Estonia

Environmental stratifications provide the framework for efficient surveillance and monitoring of biodiversity and ecological resources, as well as modelling exercises. An obstacle for agricultural landscape monitoring in Estonia has been the lack of a framework for the objective selection of monitoring sites. This paper describes the construction and testing of the Environmental Stratification of Estonia (ESE). Principal components analysis was used to select the variables that capture the most amount of variation. Seven climate variables and topography were selected and subsequently subjected to the ISODATA clustering routine in order to produce relatively homogeneous environmental strata. The ESE contains eight strata, which have been described in terms of soil, land cover and climatic parameters. In order to assess the reliability of the stratification procedure for the selection of monitoring sites, the ESE was compared with the previous map of Landscape Regions of Estonia and correlated with five environmental data sets. All correlations were significant. The stratification has therefore already been used to extend the current series of samples in agricultural landscapes into a more statistically robust series of monitoring sites. The potential for applying climate change scenarios to assess the shifts in the strata and associated ecological impacts is also examined.</p

Algorithm Construction and Numerical Solution Based on the Gradient Method of One Inverse Problem for the Acoustics Equation

The paper considers the problem of continuation of solutions of hyperbolic equations from a part of the domain boundary. These problems include the Cauchy problem for a hyperbolic equation with data on a timelike surface. In the inverse problems, the inhomogeneities are located at some depth under the medium layer, the parameters of which are known. In this case, an important tool for practitioners are the problems of continuation of geophysical fields from the Earth's surface towards the lay of inhomogeneities. In equations of mathematical physics, solution of the continuation problem from part of the boundary is in many cases strongly ill-posed problems in classes of functions of finite smoothness. The ill-posedness of this problem is considered, that is, the example of Hadamard, a Cauchy problem for a hyperbolic equation, is given. The physical formulation of the continuation problem is considered and reduced to the inverse problem. The definition of the generalized solution is formulated and the correctness of the direct problem is presented in the form of a theorem. The inverse problem is reduced to the problem of minimizing the objective functional. The objective functional is minimized by the Landweber method. By the increment of the functional, we consider the perturbed problem for the direct problem. We multiply the equation of the perturbed problem by some function and integrate by parts, we obtain the formulation of the conjugate problem. After that, we get the gradient of the functional. The algorithm for solving the inverse problem is listed. A finite-difference algorithm for the numerical solution of the problem is presented. The numerical solution of the direct problem is performed by the method of inversion of difference schemes. The results of numerical calculations are presente

The Control of Population Tumor Cells via Compensatory Effect

Mathematical models and simulation studies are powerful tools to investigate dynamic properties of complex systems. Complex models with constant parameters often approach a steady state. In this research, we present an overview of mathematical approaches applied to the description of control population tumor cells. We are researching the influence of D-factor on tumor cells population. We called it compensatory effect. There is Vaccination as biological analogue of the compensator effect. D-factor is presented as catastrophe theory’s fold form. Further, numeric results of model experiments are showing that this approach is positive efficient

The Control of Population Tumor Cells via Compensatory Effect

Abstract: Mathematical models and simulation studies are powerful tools to investigate dynamic properties of complex systems. Complex models with constant parameters often approach a steady state. In this research, we present an overview of mathematical approaches applied to the description of control population tumor cells. We are researching the influence of D-factor on tumor cells population. We called it compensatory effect. There is Vaccination as biological analogue of the compensator effect. D-factor is presented as catastrophe theory’s fold form. Further, numeric results of model experiments are showing that this approach is positive efficient

Impact of Frailty and Prefrailty on Outcomes of Transcatheter or Surgical Aortic Valve Replacement

Background: Randomized trials have shown short- and mid-term benefits with transcatheter versus surgical aortic valve replacement (TAVR versus SAVR) for patients at intermediate or low-risk for surgery. Frailty and prefrailty could explain some of this benefit due to an impaired ability to recover fully from a major surgical procedure. Methods: We examined 2-year outcomes (survival and Kansas City Cardiomyopathy Questionnaire [KCCQ] scores) among patients at intermediate or low surgical risk treated with transfemoral-TAVR or SAVR within the PARTNER (Placement of Aortic Transcatheter Valves) 2A trial, SAPIEN 3 intermediate-risk registry, and PARTNER 3 trial. Frailty was examined as a continuous variable based on grip strength, gait speed, serum albumin, and activities of daily living. We tested the interaction of frailty markers by treatment (TAVR versus SAVR) in proportional hazards regression models (survival) and piecewise linear regression models (KCCQ), adjusting for patient demographic and clinical factors. Results: Among the 3025 patients in the analytic cohort (2003 TAVR, 1022 SAVR; mean age 79.3 years, 61.6% men), 799 (26.4%) were nonfrail, 2041 (67.5%) were prefrail (1–2 frailty markers), and 185 (6.1%) were frail (3–4 frailty markers). Increasing frailty (none versus prefrail versus frail) was associated with higher 2-year mortality (5.5% versus 11.1% versus 22.8%; log-rank P &lt;0.001) and worse 2-year health status among survivors (KCCQ scores adjusted for baseline: 84.8 versus 79.6 versus 77.4, P &lt;0.001). In multivariable models, there were no significant interactions between frailty markers and treatment group for either survival (interaction P =0.39) or health status (interaction P &gt;0.47 for all time points). Conclusions: In a cohort of older patients with severe aortic stenosis who were at low or intermediate surgical risk, increasing frailty markers were associated with worse 2-year mortality and greater health status impairment after either TAVR or SAVR, but there were no significant interactions between type of valve replacement and frailty with respect to either outcome. </jats:sec