RESEARCH ON THE INFLUENCE OF TEMPERATURE ON THE ABILITY TO PROCESS MIXES OF POLYMERS WITH FULLERENES

In the article the influence of fullerene-containing technical carbon (FTC) on rheological properties of rubbers is shown. The general dependence of the injected FTC concentration and the smelt fluidity indicator before and after the temperature influence has been identified

Depth distribution of absorbed dose on the external surface of Cosmos 1887 biosatellite

Significant absorbed dose levels exceeding 1.0 Gy day(exp -1) have been measured on the external surface of the Cosmos 1887 biosatellite as functions of depth in stacks of thin thermoluminescent detectors (TLD's) made in U.S.S.R. and U.S.A. The dose was found to decrease rapidly with increasing absorber thickness, thereby indicating the presence of intensive fluxes of low-energy particles. Comparison between the U.S.S.R. and U.S.A. results and calculations based on the Vette Model environment are in satisfactory agreement. The major contribution to the dose under thin shielding thickness is shown to be from electrons. The fraction of the dose due to protons and heavier charged particles increases with shielding thickness

Radiobiological experiments with plant seeds aboard the biosatellite Cosmos 1887

The effects of spaceflight factors on the seeds of Arabidopsis thaliana and Crepis capillaris were studied. The seeds were located inside the satellite in an open space, protected with aluminum foil and also exposed without the foil cover. When the seeds were in open space without any protection, their viability was found to be suppressed; the survival rate and fertility of plants grown from these seeds were also diminished. An increase in the frequency of chromosome aberrations (CA) and in the number of multiple injuries was registered in this case. Experiments with the aluminum foil shielding showed a decrease in the suppression of the seeds' viability, but mutational changes were found to be even more increased, while the survival rate and fertility of the plants decreased. An increase in the thickness of shielding resulted in a decrease in the effects up to the level of the control, except for the effects connected with CA and fertility of the plants. Analysis of the results shows that these impairments can be ascribed to the action of single heavy charged particles (HCP). The seeds can thus be regarded as an integral biological 'dosimeter' which allows estimation of the total effects of radiation, ecological and biological factors

Potential of machine learning methods in operational risk stratification in patients with coronary artery disease scheduled for coronary bypass surgery

Aim. To develop and evaluate the effectiveness of models for predicting mortality after coronary bypass surgery, obtained using machine learning analysis of preoperative data.Material and methods. As part of a cohort study, a retrospective prediction of in-hospital mortality after coronary artery bypass grafting (CABG) was performed in 2182 patients with stable coronary artery disease. Patients were divided into 2 following samples: learning (80%, n=1745) and training (20%, n=437). The initial ratio of surviving (n=2153) and deceased (n=29) patients in the total sample indicated a pronounced class imbalance, and therefore the resampling method was used in the training sample. Five machine learning (ML) algorithms were used to build predictive risk models: Logistic regression, Random Forrest, CatBoost, LightGBM, XGBoost. For each of these algorithms, cross-validation and hyperparameter search were performed on the training sample. As a result, five predictive models with the best parameters were obtained. The resulting predictive models were applied to the learning sample, after which their performance was compared in order to determine the most effective model.Results. Predictive models implemented on ensemble classifiers (CatBoost, LightGBM, XGBoost) showed better results compared to models based on logistic regression and random forest. The best quality metrics were obtained for CatBoost and LightGBM based models (Precision — 0,667, Recall — 0,333, F1-score — 0,444, ROC AUC — 0,666 for both models). There were following common high-ranking parameters for deciding on the outcome for both models: creatinine and blood glucose levels, left ventricular ejection fraction, age, critical stenosis (>70%) of carotid arteries and main lower limb arteries.Conclusion. Ensemble machine learning methods demonstrate higher predictive power compared to traditional methods such as logistic regression. The prognostic models obtained in the study for preoperative prediction of in-hospital mortality in patients referred for CABG can serve as a basis for developing systems to support medical decision-making in patients with coronary artery disease

Study of operating modes of STRAUS-R accelerator

The description of a pulsed electron accelerator STRAUS-R (3.5 MeV, 60 kA, 60 ns) and results of its experimental research for two operation modes are given. In the mode of electron beam focusing the accelerator provides the focal spot of 3-4 mm diameter on a target and maximum exposure dose of 27 R at 1-m distance from the output window. In the irradiating mode the maximum dose achieves 36 R at 1-m distance from the target with inhomogeneity ≤ 30% within the area 0.36 m² (irradiation spot diameter is 0.6 m).Приведены описание и результаты исследований импульсного электронного ускорителя СТРАУС-Р (3,5 МэВ, 60 кА, 60 нс) в двух режимах его работы. В режиме фокусировки электронного пучка ускоритель обеспечивает получение на мишени фокусного пятна диаметром 3…4 мм при максимальной дозе тормозного излучения 27 Р на расстоянии 1 м от выходного фланца. В облучательном режиме максимальная доза тормозного излучения на расстоянии 1 м от мишени по оси ускорителя достигает 36 Р с неоднородностью ≤ 30% на площади 0,36 м² (диаметр пятна облучения 0,6 м).Наведено опис і результати досліджень імпульсного електронного прискорювача СТРАУС-Р (3,5 МеВ, 60 кА, 60 нс) у двох режимах його роботи. У режимі фокусування електронного пучка прискорювач забезпечує одержання на мішені фокусної плями діаметром 3...4 мм при максимальній дозі гальмівного випромінювання 27 Р на відстані 1 м від вихідного фланця. При опроміненні максимальна доза гальмового випромінювання на відстані 1 м від мішені по осі прискорювача досягає 36 Р с неоднорідністю ≤ 30% на площі 0,36 м² (діаметр плями опромінення 0,6 м)

Exploiting parallelism in decomposition methods for constraint satisfaction

Constraint Satisfaction Problems (CSPs) are NP-complete in general, however, there are many tractable subclasses that rely on the restriction of the structure of their underlying hypergraphs. It is a well-known fact, for instance, that CSPs whose underlying hypergraph is acyclic are tractable. Trying to define “nearly acyclic” hypergraphs led to the definition of various hypergraph decomposition methods. An important member in this class is the hypertree decomposition method, introduced by Gottlob et al. It possesses the property that CSPs falling into this class can be solved efficiently, and that hypergraphs in this class can be recognized efficiently as well. Apart from polynomial tractability, complexity analysis has shown, that both afore-mentioned problems lie in the low complexity class LOGCFL and are thus moreover efficiently parallelizable. A parallel algorithm has been proposed for the “evaluation problem”, however all algorithms for the “recognition problem” presented to date are sequential.The main contribution of this dissertation is the creation of an object oriented programming library including a task scheduler which allows the parallelization of a whole range of computational problems, fulfilling certain complexity-theoretic restrictions. This library merely requires the programmer to provide the implementation of several classes and methods, representing a general alternating algorithm, while the mechanics of the task scheduler remain hidden. In particular, we use this library to create an efficient parallel algorithm, which computes hypertree decompositions of a fixed width.Another result of a more theoretical nature is the definition of a new type of decomposition method, called Balanced Decompositions. Solving CSPs of bounded balanced width and recognizing such hypergraphs is only quasi-polynomial, however still parallelizable to a certain extent. A complexity-theoretic analysis leads to the definition of a new complexity class hierarchy, called the DC-hierarchy, with the first class in this hierarchy, DC1 , precisely capturing the complexity of solving CSPs of bounded balanced width.</p

THE ADHESION OF THE CELLS AND REGULATION OF THE CELLULAR CULTURES GROWTH

The new position about the role of the intracellular pH has been advanced, depending on the growth of the normal cells from adhesion to the solid substrate in the regulation of the growth of the normal and transformed cells. Advanced has been a new position about that the intercellular contacts do not supress the growth of the cells in the monolayer and play the key role in realization of the multilayer growth of the normal cells of the culture. The new methods and the equipment for growing of the multilayer cellular cultures, for study of the cells and its microsurrounding have been developed. The results have been used as the base for the investigations of regulation of the normal and tumor cell growth, for the search of means of the tumor chemiotherapy, for the development of methods and equipment of growing and investigation of the multilayer cellular cultures in the biotechnology.Available from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Influence of

The influence of marine higher plants Zostera marina and Z. noltei on the composition, species richness and coenotic diversity of the phytobenthos of sandy and silty soils of the Taman Bay in the Azov Sea at the depths from 0.5 to 3 m has been investigated. It is shown that 1) macrophytobenthic communities with a high degree of Z. noltei and Z. marina dominance (DD), both at very small and relatively large sites, are characterized by lower species richness than the communities with low DD; 2) that being said, for the majority of co-occurring species it is possible to grow in coenoses with any DD; 3) accordingly, about the same number of species can grow at the small community sites with low DD and at the larger sites with high DD; 4) DD has little to no influence on the species diversification of coenoses. However, both the growth of Zostera marina and Z. noltei and the decrease in their participation can lead to considerable drop in occurrence of some macroalgae species or to disappearance of those species from a community

Exploiting parallelism in decomposition methods for constraint satisfaction

Constraint Satisfaction Problems (CSPs) are NP-complete in general, however, there are many tractable subclasses that rely on the restriction of the structure of their underlying hypergraphs. It is a well-known fact, for instance, that CSPs whose underlying hypergraph is acyclic are tractable. Trying to define “nearly acyclic” hypergraphs led to the definition of various hypergraph decomposition methods. An important member in this class is the hypertree decomposition method, introduced by Gottlob et al. It possesses the property that CSPs falling into this class can be solved efficiently, and that hypergraphs in this class can be recognized efficiently as well. Apart from polynomial tractability, complexity analysis has shown, that both afore-mentioned problems lie in the low complexity class LOGCFL and are thus moreover efficiently parallelizable. A parallel algorithm has been proposed for the “evaluation problem”, however all algorithms for the “recognition problem” presented to date are sequential. The main contribution of this dissertation is the creation of an object oriented programming library including a task scheduler which allows the parallelization of a whole range of computational problems, fulfilling certain complexity-theoretic restrictions. This library merely requires the programmer to provide the implementation of several classes and methods, representing a general alternating algorithm, while the mechanics of the task scheduler remain hidden. In particular, we use this library to create an efficient parallel algorithm, which computes hypertree decompositions of a fixed width. Another result of a more theoretical nature is the definition of a new type of decomposition method, called Balanced Decompositions. Solving CSPs of bounded balanced width and recognizing such hypergraphs is only quasi-polynomial, however still parallelizable to a certain extent. A complexity-theoretic analysis leads to the definition of a new complexity class hierarchy, called the DC-hierarchy, with the first class in this hierarchy, DC1 , precisely capturing the complexity of solving CSPs of bounded balanced width.EThOS - Electronic Theses Online ServiceGBUnited Kingdo