50 research outputs found

    The Operators Aγ = γA + -γA for a Class of Nondissipative Operators A with a Limit of the Corresponding Correlation Function

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    2000 Mathematics Subject Classification: Primary 47A48, Secondary 60G12In this work we present the operators Aγ = γA + -γA with Re γ = 1/2 in the case of an operator A from the class of nondissipative operators generating nonselfadjoint curves, whose correlation functions have a limit as t → ±∞. The asympthotics of the stationary curves e^(itAγ)f as t → ±∞ onto the absolutely continuous subspace of Aγ are obtained. These asymptotics and the obtained asymptotics in [9] of the nondissipative curves e^(itA)f allow to construct the scattering theory for the couples (Aγ , A) and (A, Aγ). We consider the basic terms from the scattering theory - wave operators, a scattering operator and the question of a similarity of A and Aγ. We obtain explicitly the wave operators, the scattering operator and the similarity of A and Aγ.Partially supported by Grant MM-810/98 of MESC and by Scientific Research Grant 21/09.05.2001 of Shumen University

    Triangular Models and Asymptotics of Continuous Curves with Bounded and Unbounded Semigroup Generators

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    2000 Mathematics Subject Classification: Primary 47A48, Secondary 60G12.In this paper classes of K^r -operators are considered – the classes of bounded and unbounded operators A with equal domains of A and A*, finite dimensional imaginary parts and presented as a coupling of a dissipative operator and an antidissipative one with real absolutely continuous spectra and the class of unbounded dissipative K^r -operators A with different domains of A and A* and with real absolutely continuous spectra. Their triangular models are presented. The asymptotics of the corresponding continuous curves with generators from these classes are obtained in an explicit form. With the help of the obtained asymptotics the scattering theory for the couples (A*, A) when A belongs to the introduced classes is constructed.Partially supported by Grant MM-1403/04 of MESC and by Scientific Research Grants 19/13.03.2003 and 26/01.04.2004 of Shumen University

    The need and satisfaction of the patients of hospice services in Varna Region

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    Introduction: In the context of the severe demographic situation in our country, the problem of the hospice movement stands out. In an ageing society, people who need hospice care are constantly increasing. Chronically sick patients, especially those with progressive disease, pose a serious problem because they need specific care. Some such care is provided in hospices, which in our country prove to be inadequate.Purpose: To investigate the need and satisfaction of patients from hospice services in Varna region.Material and Methods: The survey was conducted in the first quarter of 2017 and covers 85 people, the users of hospice services offered in some of the hospices in Varna. Sociological methods were used: document analysis, survey method and statistical methods.Results and Discussion: Respondents are of different educational attainment and social status over a broader age range. There are residents of Varna, the surrounding settlements and other big cities in the country. Some of the respondents were staying in different hospices and considered that they were insufficient for the city of Varna. Almost everyone knows the administrative organization and the internal order of the hospice, they are happy with the medical service but have some recommendations for improving the lifestyle. Patients of hospice services are responsible for searching and choosing a hospice service to enter by using different sources of information

    Automated Assessment of a Students Circulatory System Functional State Using Martine's Test

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    Background. The systematic self-control of students' health state allows optimizing the educational process organization of physical education and contribute improving the functioning of body systems. One of the common methods of such observation is the functional Martine's test, which provides an opportunity to investigate the dynamics of changes in blood pressure and heart rate between the resting state and every minute for five minutes after the load. In most cases, this load characteristic sufficiently fully reflects the student's cardiovascular system state. The determination of the characteristic patterns of such states will allow offering a mechanism for assessing the functional state of the circulatory system. The regular Martine's testing will allow observing the dynamics and evaluating changes in the body during the observation period. Objective. Creation of an automated system for assessing of a student’s circulatory system functional state changes. Methods. The students database of the National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” created during the research by the Department of Physical Education, was used for the study. To determine the functional patterns, separately for boys and girls, cluster analysis was used by the  "k-means" method in the parameter space of the blood pressure and heart rate measured during the functional Martine's test. As a result, 7 clusters of states for young men and 8 clusters for girls were obtained. Clusters differ significantly in the nature of the response of blood pressure and heart rate to the load test. The centroids of the resulting clusters were further considered as functional patterns (the most typical representatives) of the body's response to the test physical load. The assessment of the circulatory system functional state is calculated by comparing the student test data with the previously defined functional patterns by the minimum Euclidean distance criterion. Conclusions about the functional state of the system are formed. Results. The clusters of the circulatory system functional states in the extended space of blood pressure and heart rate parameters of functional Martine's test are obtained. The clusters correspond to the normal states and different stages of the regulatory reserves reduction of the body. The algorithm allowing to consider features of an organism functional state at essential deviation of Martine's test indicators from a certain functional pattern is developed. This admits controlling the individual level of physical activity, adapting the training program and identifying conditions requiring additional medical control. Conclusions. As a study result, the automated system for assessing the functional state of technical university students circulatory system using Martine's test was developed. The system relates observation to one of the study sample clusters that were obtained using the "k-means" method. For additional information on the state of the circulatory system, the average radius of the cluster is used, since objects that are far removed from the center may have properties similar to those of a neighboring cluster. The developed system provides an opportunity for screening control the students cardiovascular system state during the educational process

    (7aR*,12bS*)-8,12b-Dihydro-7aH-indeno­[1′,2′:5,6][1,4]selenazino[2,3,4-ij]quinolin-13-ium hydrogen sulfate

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    In the title compound, C18H14NSe+·HSO4 −, the cyclo­pentene ring in the cation has an envelope conformation while the central six-membered 1,4-selenazine ring adopts a sofa conformation. The dihedral angle between the planes of the terminal benzene rings is 68.08 (11)°. In the crystal, the anions form chains along the c axis through O—H⋯O hydrogen bonds. Weak C—H⋯O and C—H⋯π hydrogen bonds, as well as attractive Se⋯Se [3.5608 (8) Å] inter­actions, further consolidate the crystal structure

    The stress and vascular catastrophes in newborn rats: mechanisms preceding and accompanying the brain hemorrhages

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    In this study, we analyzed the time-depended scenario of stress response cascade preceding and accompanying brain hemorrhages in newborn rats using an interdisciplinary approach based on: a morphological analysis of brain tissues, coherent-domain optical technologies for visualization of the cerebral blood flow, monitoring of the cerebral oxygenation and the deformability of red blood cells (RBCs). Using a model of stress-induced brain hemorrhages (sound stress, 120 dB, 370 Hz), we studied changes in neonatal brain 2, 4, 6, 8 h after stress (the pre-hemorrhage, latent period) and 24 h after stress (the post-hemorrhage period). We found that latent period of brain hemorrhages is accompanied by gradual pathological changes in systemic, metabolic, and cellular levels of stress. The incidence of brain hemorrhages is characterized by a progression of these changes and the irreversible cell death in the brain areas involved in higher mental functions. These processes are realized via a time-depended reduction of cerebral venous blood flow and oxygenation that was accompanied by an increase in RBCs deformability. The significant depletion of the molecular layer of the prefrontal cortex and the pyramidal neurons, which are crucial for associative learning and attention, is developed as a consequence of homeostasis imbalance. Thus, stress-induced processes preceding and accompanying brain hemorrhages in neonatal period contribute to serious injuries of the brain blood circulation, cerebral metabolic activity and structural elements of cognitive function. These results are an informative platform for further studies of mechanisms underlying stress-induced brain hemorrhages during the first days of life that will improve the future generation's health

    Plant Growth Promoting Activity and Metal Tolerance of Bacteria Isolated from Rhizosphere of the Orchid Epipactis atrorubens Growing on Serpentine Substrates of the Middle Urals

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    В статье представлены данные, полученные при изучении бактерий, выделенных из ризосферы орхидеи Epipactis atrorubens (Hoffm.) Besser. Проведен сравнительный анализ некоторых морфологических, физиологических и биохимических характеристик ризобактерий растений, произрастающих в двух биотопах на серпентинитовых породах: в естественном лесном фитоценозе (фоновый участок) и на отвале после добычи асбеста (Свердловская область, Средний Урал). Оценка ростстимулирующей (PGP) активности выделенных штаммов не показала достоверных различий между исследованными участками по способности ризобактерий к синтезу индолил‑3-уксусной кислоты (ИУК) и солюбилизации фосфатов. Однако доля изолятов, способных к азотфиксации, была выше в ризосфере E. atrorubens, произрастающего на отвале, по сравнению с фоновым местообитанием. Устойчивость изолятов к тяжелым металлам оценивали по максимальной концентрации металла (400, 600 и 1000 мг/л соответственно для Ni, Cu и Zn), при которой отмечался рост бактерий. Показано, что ризобактерии с отвала оказались более устойчивыми к повышенным концентрациям металлов по сравнению с естественным лесным фитоценозом. На основе молекулярно-генетического анализа изолятов с наиболее выраженной PGP‑активностью (ИУК >1,0 мг/л; PO4 3- >50,0 мг/л) обнаружено сходство между изученными местообитаниями по родовой принадлежности ризобактерий E. atrorubens: выделенные штаммы принадлежали преимущественно к родам Buttiauxella и Pseudomonas. В модельных экспериментах протестирована ростстимулирующая способность четырех отобранных штаммов на семенах циннии. Инокуляция семян Pseudomonas sp. и Buttiauxella sp. не оказывала значимого влияния на их всхожесть, однако Buttiauxella sp. способствовала увеличению длины проростков в сравнении с контролем (в среднем на 25 %). Сделано предположение, что отобранные изоляты ризобактерий E. atrorubens, благодаря их ростстимулирующей активности и металлоустойчивости, могут способствовать натурализации орхидеи на техногенно нарушенной территорииThe article presents data obtained in the study of bacteria isolated from the rhizosphere of the orchid Epipactis atrorubens (Hoffm.) Besser. Analysis was carried out to compare some morphological, physiological, and biochemical characteristics of plant rhizobacteria growing on serpentine rocks in two biotopes: in the natural forest community (control habitat) and on the asbestos mine dump (the Sverdlovsk region, Middle Urals). An assessment of the plant growth promoting (PGP) activity of the isolated strains did not show significant differences in the ability of rhizobacteria to synthesize indol‑3-acetic acid (IAA) and solubilize phosphates between the study sites. However, the proportion of isolates capable of nitrogen fixation was higher in the rhizosphere of E. atrorubens growing on the dump compared to the control habitat. The tolerance of isolates to heavy metals was assessed by the maximum metal concentration (400, 600, and 1000 mg/L, respectively, for Ni, Cu, and Zn) at which bacterial growth was observed. Rhizobacteria from the dump were found to be more resistant to elevated concentrations of metals compared to their counterparts from the natural forest community. The molecular genetic analysis of isolates with the highest PGP‑activity (IAA >1.0 mg/L; PO4 3- >50.0 mg/L) revealed that most of the E. atrorubens rhizobacteria in both habitats belonged to the genera Buttiauxella and Pseudomonas. In model experiments, the PGP ability of four selected strains was tested on zinnia seeds. Seed inoculation with Pseudomonas sp. and Buttiauxella sp. did not have any significant effect on their germination; however, Buttiauxella sp. contributed to the increase in the length of seedlings compared with the control (by 25 %, on average). It has been suggested that the selected isolates of E. atrorubens rhizobacteria, due to their growth promoting activity and metal tolerance, can facilitate naturalization of the orchid in an industrially disturbed are

    The Eurasian Modern Pollen Database (EMPD), version 2

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    The Eurasian (née European) Modern Pollen Database (EMPD) was established in 2013 to provide a public database of high-quality modern pollen surface samples to help support studies of past climate, land cover, and land use using fossil pollen. The EMPD is part of, and complementary to, the European Pollen Database (EPD) which contains data on fossil pollen found in Late Quaternary sedimentary archives throughout the Eurasian region. The EPD is in turn part of the rapidly growing Neotoma database, which is now the primary home for global palaeoecological data. This paper describes version 2 of the EMPD in which the number of samples held in the database has been increased by 60 % from 4826 to 8134. Much of the improvement in data coverage has come from northern Asia, and the database has consequently been renamed the Eurasian Modern Pollen Database to reflect this geographical enlargement. The EMPD can be viewed online using a dedicated map-based viewer at https://empd2.github.io and downloaded in a variety of file formats at https://doi.pangaea.de/10.1594/PANGAEA.909130 (Chevalier et al., 2019)Swiss National Science Foundation | Ref. 200021_16959
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