513 research outputs found
Heart Failure with Preserved Ejection Fraction
Heart failure with preserved ejection fraction (HFpEF) is now recognized as a major and growing public health problem worldwide. This heart failure subtype disproportionately affects women and the elderly and is commonly associated with other cardiovascular comorbidities, such as hypertension, diabetes and chronic kidney disease. There are uncertainties and debates regarding the definition, diagnosis and pathophysiology with the consequence that all outcome trials performed so far cannot yield an effective treatment as in heart failure with reduced ejection fraction (HFrEF). Here we present an overview of epidemiology, pathophysiology, diagnosis and therapeutic approaches emerging from large outcome clinical trials
Hybrid Intelligent Optimization Methods for Engineering Problems
The purpose of optimization is to obtain the best solution under certain conditions. There are numerous optimization methods because different problems need different solution methodologies; therefore, it is difficult to construct patterns. Also mathematical modeling of a natural phenomenon is almost based on differentials. Differential equations are constructed with relative increments among the factors related to yield. Therefore, the gradients of these increments are essential to search the yield space. However, the landscape of yield is not a simple one and mostly multi-modal. Another issue is differentiability. Engineering design problems are usually nonlinear and they sometimes exhibit discontinuous derivatives for the objective and constraint functions. Due to these difficulties, non-gradient-based algorithms have become more popular in recent decades.
Genetic algorithms (GA) and particle swarm optimization (PSO) algorithms are popular, non-gradient based algorithms. Both are population-based search algorithms and have multiple points for initiation. A significant difference from a gradient-based method is the nature of the search methodologies. For example, randomness is essential for the search in GA or PSO. Hence, they are also called stochastic optimization methods. These algorithms are simple, robust, and have high fidelity. However, they suffer from similar defects, such as, premature convergence, less accuracy, or large computational time. The premature convergence is sometimes inevitable due to the lack of diversity. As the generations of particles or individuals in the population evolve, they may lose their diversity and become similar to each other. To overcome this issue, we studied the diversity concept in GA and PSO algorithms.
Diversity is essential for a healthy search, and mutations are the basic operators to provide the necessary variety within a population. After having a close scrutiny of the diversity concept based on qualification and quantification studies, we improved new mutation strategies and operators to provide beneficial diversity within the population. We called this new approach as multi-frequency vibrational GA or PSO. They were applied to different aeronautical engineering problems in order to study the efficiency of these new approaches. These implementations were: applications to selected benchmark test functions, inverse design of two-dimensional (2D) airfoil in subsonic flow, optimization of 2D airfoil in transonic flow, path planning problems of autonomous unmanned aerial vehicle (UAV) over a 3D terrain environment, 3D radar cross section minimization problem for a 3D air vehicle, and active flow control over a 2D airfoil.
As demonstrated by these test cases, we observed that new algorithms outperform the current popular algorithms. The principal role of this multi-frequency approach was to determine which individuals or particles should be mutated, when they should be mutated, and which ones should be merged into the population. The new mutation operators, when combined with a mutation strategy and an artificial intelligent method, such as, neural networks or fuzzy logic process, they provided local and global diversities during the reproduction phases of the generations. Additionally, the new approach also introduced random and controlled diversity. Due to still being population-based techniques, these methods were as robust as the plain GA or PSO algorithms. Based on the results obtained, it was concluded that the variants of the present multi-frequency vibrational GA and PSO were efficient algorithms, since they successfully avoided all local optima within relatively short optimization cycles
The Moderator Effect of the Multinationality Factor on the Relationships Between Organizational Structure and Managerial Competency
The purpose of this study is to reveal the relationship between the organizational structure perceptions and the managerial competence perceptions of individuals working as managers in national and multinational companies in Turkey and to investigate whether these perceptions are affected by “the multi-nationality” factor. In this context, the relationship between the estimation variable "Organizational Structure" and the outcome variable "Managerial Competence" is researched; additionally, the effects of both the estimation variable and the organizational and individual demographic variables on the outcome variable are analyzed. The main research question is whether the managers’ perception of organizational structure affects the perception of managerial competence. The main research hypothesis is that the perception of organizational structure has a positive effect on the perception of managerial competence. The measurement tools developed by the researcher were applied to entry-, middle- and senior-level managers. The research data were obtained from 330 managers working in national companies and 270 managers working in multinational companies operating in Turkey. The results of this research indicated that there was a statistically significant relationship between the estimation variable and the outcome variable and that the perception of organizational structure affects the perception of managerial competence (R2 = 0.530, p <0.05). It was observed that the organizational structure factor explained 53% of the managerial competence factor. In addition, when organizational demographic variables such as “the number of personnel working in the department” and “the model of organization” and individual demographic variables such as “management level” and “total work experience” are considered as factors in the analyses, it was observed that the R2 parameter showing a relationship between the estimation variable and the outcome variable has increased to 62%. Other individual and demographic variables did not contribute to the model, and as a result, their effects are concluded to be either equal or constant. The moderator effect of the "multi-nationality" factor was seen to be not statistically significant, and the moderator effect was not found (R2 = 0.001, p = 0.253> 0.05)
Relationship between Foreign Trade Deficit and Special Consumption Tax Revenues with Structural Breaks in Turkey
Trade balance is one of the most important indicators of economic stability. The increasing capital inputs in recent years, where capital liberalization is highly realized, make local currency more valuable. During this process that import grew while export went down, the foreign trade deficit has become greater, which impairs competition. Special consumption taxes that have been implemented more actively in recent years are intended to reduce domestic demand for import and avoid foreign trade deficits. This study examines whether there is a relation between the foreign trade deficit and special consumption taxes for Turkey between 01/2006 and 05/2013 using the Zivot-Andrews unit root test based on structural breaks, the Gregory-Hansen cointegration test and the Toda-Yamamoto causality analysis. Empirical practices in the study showed that neither series were stationary in level and there was no long-term relation between them. As a result of the Toda-Yamamoto method based on the Granger causality analysis, bidirectional causality was determined in between the variables. Keywords: Foreign trade deficit, Special consumption tax, Structural change, Toda-Yamamoto causality analysi
Involuntary Dissolution: Theory and Operation in Publicly Traded Corporations
Involuntary dissolution is recognized as the primary mechanism to monitor opportunism and remedy the aggrieved minority shareholders of corporations. Contrary to general understanding, involuntary dissolution is not idiosyncratic to close corporations. However, its application to publicly traded corporations requires an approach different than the one for close corporations. This note discusses and recommends the approach necessary to justify and effectively enforce involuntary dissolution statutes’ application in the context of publicly traded corporations. It expresses the opinion that the contractual view of corporate law would provide the theoretical basis necessary to construe the statute for publicly traded corporations and exemplifies its approach through the shareholder oppression law of the U.S. corporate law
THE RELATIONSHIP BETWEEN ADAPTATION TO PREGNANCY AND PRENATAL ATTACHMENT IN HIGH-RISK PREGNANCIES
Background: Although pregnancy is a physiological process, there are various changes which need to be adapted to. Adaptation
and prenatal attachment are important for both the mother’s and baby’s health. These situations are more crucial for women with high-risk pregnancy. The study aimed to determine the relationship between adaptation to pregnancy and prenatal attachment among women with high-risk pregnancy, as well as socio-demographic and obstetric parameters which affected this adaptation.
Subjects and methods: This descriptive and analytic study’s data were collected from high-risk pregnant women (n=479) who
were receiving treatment at two public hospitals in Turkey using Prenatal Self-Evaluation Form (PSEQ) and Prenatal Attachment Inventory (PAI). Descriptive statistics, correlation and comparative analyses were used in data analyses.
Results: It was determined that adaptation to pregnancy was medium and prenatal attachment was high in high-risk pregnant
(PSEQ mean score:159.43±27.05; PAI mean score: 63.79±10.75). There was a significant negative relationship between the scales (r=-0.556, p<0.01). This relationship showed that as adaptation to pregnancy increased, prenatal attachment also increased. There was significant difference in the PSEQ by age, educational status, employment status, marital status, year of marriage, spouse\u27s educational and employment status, having health insurance, family type, income status, spouse\u27s attitudes towards pregnancy, number of pregnancies, number of births, having living children, whether the pregnancy was planned, pregnancy week and prenatal attachment.
Conclusion: According to results, there is relationship between adaptation to pregnancy and prenatal attachment in high-risk
pregnancies and some sociodemographic and obstetric factors affects adaptation to pregnancy. Determining these factors can serve as a guide for preventing and reducing additional problems that may be encountered in pregnancy and postpartum period in highrisk pregnant women
Smrzavanje i otapanje uzoraka mlijeka prije nacjepljivanja na hranjivu podlogu poboljšava dijagnosticiranje stafilokoknog mastitisa u krava.
Diagnosis of staphylococcal mastitis cases may sometimes prove problematic due to the nature of the bacterium. Thus, in the present study, the effect of freezing and thawing bovine milk samples on the performance of standard cultures of staphylococcal mastitis was investigated to improve the diagnosis. Each of a total of 228 quarter milk samples from clinical and subclinical mastitis cases was plated on 7 % sheep blood agar directly, and after first being subjected to a process of freezing and thawing. The culture results from two methods were compared on the basis of Staphylococcus spp. positive udder counts and alteration in colony counts of the strains. In the first method, Staphylococcus spp. were isolated from 91 milk samples. In the second method, Staphylococcus spp. were isolated from an additional 11 milk samples that were negative in the first method. Staphylococcus spp. positive udder counts were found to be significantly different between the two methods. The changes in colony counts of the strains between the two methods were also found to be statistically significant in both clinical and subclinical mastitis cases, with the second method performing better. Consequently, these results indicate that a simple preculture step consisting of freezing and thawing milk samples has advantages for more sensitive diagnosis of staphylococcal mastitis in cattle milk.Zbog osobina uzročnika dijagnostika stafi lokoknog mastitisa ponekad može biti otežana. Radi poboljšanja dijagnostike u ovom je istraživanju istražen učinak smrzavanja i otapanja pretraživanih uzoraka mlijeka prije provođenja standardnog postupka uzgoja uzročnika. Svaki od 228 uzetih uzoraka mlijeka kod kliničkog i supkliničkog mastitisa bio je nacijepljen na krvni agar sa 7 % ovčje krvi izravno te nakon postupka smrzavanja i otapanja. Rezultati uzgoja obaju postupaka bili su uspoređeni na osnovi broja vimena pozitivnih na stafilokoke i broja poraslih bakterijskih kolonija. Kod izravnog nacjepljivanja Staphylococcus spp. bio je izdvojen iz 91 uzorka mlijeka. Nakon smrzavanja i otapanja Staphylococcus spp. bio je izdvojen iz još 11 uzoraka, koji su bili negativni kod izravnog nacjepljivanje bez prethodnoga smrzavanja i otapanja. Broj vimena pozitivnih na Staphylococcus spp. bio je statistički značajno različit između tih dvaju pretraživanih postupaka. Razlike u broju kolonija izolata bile su također statistički značajne između rabljenih postupaka kod dijagnosticiranja kliničkog i supkliničkog mastitisa. Boljim se pokazao postupak prethodnog smrzavanja i otapanja uzoraka mlijeka. Rezultati upućuju na zaključak da smrzavanje i otapanje uzoraka mlijeka prije nacjepljivanja na hranjivu podlogu ima prednosti s obzirom da se taj postupak pokazao osjetljivijim za dokazivanje stafilokoka kod pojave mastitisa u mliječnih krava
THE RELATIONSHIP BETWEEN ADAPTATION TO PREGNANCY AND PRENATAL ATTACHMENT IN HIGH-RISK PREGNANCIES
Background: Although pregnancy is a physiological process, there are various changes which need to be adapted to. Adaptation
and prenatal attachment are important for both the mother’s and baby’s health. These situations are more crucial for women with high-risk pregnancy. The study aimed to determine the relationship between adaptation to pregnancy and prenatal attachment among women with high-risk pregnancy, as well as socio-demographic and obstetric parameters which affected this adaptation.
Subjects and methods: This descriptive and analytic study’s data were collected from high-risk pregnant women (n=479) who
were receiving treatment at two public hospitals in Turkey using Prenatal Self-Evaluation Form (PSEQ) and Prenatal Attachment Inventory (PAI). Descriptive statistics, correlation and comparative analyses were used in data analyses.
Results: It was determined that adaptation to pregnancy was medium and prenatal attachment was high in high-risk pregnant
(PSEQ mean score:159.43±27.05; PAI mean score: 63.79±10.75). There was a significant negative relationship between the scales (r=-0.556, p<0.01). This relationship showed that as adaptation to pregnancy increased, prenatal attachment also increased. There was significant difference in the PSEQ by age, educational status, employment status, marital status, year of marriage, spouse\u27s educational and employment status, having health insurance, family type, income status, spouse\u27s attitudes towards pregnancy, number of pregnancies, number of births, having living children, whether the pregnancy was planned, pregnancy week and prenatal attachment.
Conclusion: According to results, there is relationship between adaptation to pregnancy and prenatal attachment in high-risk
pregnancies and some sociodemographic and obstetric factors affects adaptation to pregnancy. Determining these factors can serve as a guide for preventing and reducing additional problems that may be encountered in pregnancy and postpartum period in highrisk pregnant women
R744 Flow Boiling Heat Transfer With and Without Oil at Low Temperatures in 11.2 mm Horizontal Smooth Tube
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