The aim of this study was to investigate the discrimination power of standard long-term heart rate variability (HRV) measures for the diagnosis of chronic heart failure (CHF). The authors performed a retrospective analysis on four public Holter databases, analyzing the data of 72 normal subjects and 44 patients suffering from CHF. To assess the discrimination power of HRV measures, an exhaustive search of all possible combinations of HRV measures was adopted and classifiers based on Classification and Regression Tree (CART) method was developed, which is a non-parametric statistical technique. It was found that the best combination of features is: Total spectral power of all NN intervals up to 0.4 Hz (TOTPWR), square root of the mean of the sum of the squares of differences between adjacent NN intervals (RMSSD) and standard deviation of the averages of NN intervals in all 5-min segments of a 24-h recording (SDANN). The classifiers based on this combination achieved a specificity rate and a sensitivity rate of 100.00 and 89.74%, respectively. The results are comparable with other similar studies, but the method used is particularly valuable because it provides an easy to understand description of classification procedures, in terms of intelligible “if … then …” rules. Finally, the rules obtained by CART are consistent with previous clinical studies.
Intensive corn cultivation is predominant in current agriculture of the Una-Sana Canton. One of the corn cultivation methods in agro-ecosystem is reduced cultivation. The paper presents the experiment of “Osmak žuti” (eight-row yellow) corn cultivation on two control sites with application of reduced and intensive cultivation in Cazin municipality. The objectives of this research were to examine the possibility of application of reduced corn cultivation; analyze statistical variation elements (length, circumference and weight of corn cob); and determine cost effectiveness of reduced relative to intensive production. The results indicate extremely high statistically significant difference (p<0.001) for all parameters in both cultivation methods. The cost effectiveness of reduced relative to intensive cultivation of Osmak žuti corn is higher by 36%. The experiment encourages introduction of reduced corn cultivation practice.
Cancer is caused by multiple genetic alterations leading to uncontrolled cell proliferation through multiple pathways. Malignant cells arise from a variety of genetic factors, such as mutations in tumor suppressor genes (TSGs) that are involved in regulating the cell cycle, apoptosis, or cell differentiation, or maintenance of genomic integrity. Tumor suppressor mouse models are the most frequently used animal models in cancer research. The anti-tumorigenic functions of TSGs, and their role in development and differentiation, and inhibition of oncogenes are discussed. In this review, we summarize some of the important transgenic and knockout mouse models for TSGs, including Rb, p53, Ink4a/Arf, Brca1/2, and their related genes.
Abstract Besides significant benefits, the trend of e-commerce development gives rise to a lot of challenges in terms of developing trust between the company and the consumer. A lack of trust leads to withdrawal from e-transactions. The paper is thus aimed at identifying and explaining the most important factors that affect the increase in users' trust in e-transactions. Besides an analysis of available papers in this area, a field research was conducted on a sample of 512 respondents in Bosnia and Herzegovina in order to develop a structural model of users' trust in e-transactions. Research findings confirm that the basic factors of an online trust model are: website usability, privacy, security, expected product performance, loyalty, and electronic management of customer relations (e-CRM).
Design of a motion control system, convenient for a wide range of applications in industry, space, biology, medicine, particularly including more than one physics environment is very important. Well known control architectures like trajectory tracking, compliance control, interaction force control are scientific milestones which has common control task: to maintain desired system configuration. In this concept, motion control system can be an unconstrained motion-performed interaction with neither environment nor any other system, or constrained motionsystem in contact with environment and/or other systems. This paper provides the function based design approach to formulate control of constrained system particularly bilateral systems in micromanipulation applications. The control objective aimed to maintain desired functional relations between human and environment defining convenient tasks and their proper relations on master and slave motion systems. Preliminary results concerning position tracking, force control and transparency between master and slave systems are clearly demonstrated.
SURALP is a 29 degrees-of-freedom full-body walking humanoid robot designed and constructed at Sabanci University - Turkey. The human-sized robot is actuated by DC motors, belt and pulley systems and Harmonic Drive reduction gears. The sensory equipment consists of joint encoders, force/torque sensors, inertial measurement systems and cameras. The control hardware is based on a dSpace digital signal processor. This paper reviews the design of this robot and presents experimental walking results. A posture zeroing procedure is followed after manual zeroing of the robot joints. Controllers for landing impact reduction, early landing trajectory modification, foot-ground orientation compliance, body inclination and Zero Moment Point (ZMP) regulation, and independent joint position controllers are used in zeroing and walking. A smooth walking trajectory is employed. Experimental results indicate that the reference generation and control algorithms are successful in achieving a stable and continuous walk.
In bilateral control applications, time delays in the communication channel have destabilizing effects and cause degradations in the performance of the system. In this paper, a sliding mode observer is used in conjunction with a disturbance observer to predict states of the slave system. Predicted states are then used in control formulation. Simulation and experimental results show that the proposed method avoids instability due to time delays in bilateral operation and provides satisfactory performance.
Cancer is caused by multiple genetic alterations leading to uncontrolled cell proliferation through multiple pathways. Malignant cells arise from a variety of genetic factors, such as mutations in tumor suppressor genes (TSGs) that are involved in regulating the cell cycle, apoptosis, or cell differentiation, or maintenance of genomic integrity. Tumor suppressor mouse models are the most frequently used animal models in cancer research. The anti-tumorigenic functions of TSGs, and their role in development and differentiation, and inhibition of oncogenes are discussed. In this review, we summarize some of the important transgenic and knockout mouse models for TSGs, including Rb, p53, Ink4a/Arf, Brca1/2, and their related genes.
There is no doubt that the development of diagnostic criteria has contributed greatly to epidemiological research in prion diseases, and Heath and colleagues emphasize this in surveillance studies of variant Creutzfeldt-Jakob disease (vCJD). We caution, however, against a more broad application in clinical practice, particularly in governing decisions about clinical diagnosis, communication with patients/caregivers, and access to experimental therapies. The physician looking after a young patient with an unexplained rapidly progressive neuropsychiatric syndrome, dementia, or ataxia needs to make prompt clinical decisions. There are treatable alternative diagnoses, and an early firm diagnosis is essential. The pulvinar sign on magnetic resonance imaging is often not identified when patients are first imaged, and a requirement for a clinical duration of 6 months or greater makes a probable diagnosis impossible in the early stages of disease. Physicians who have cared for families affected by vCJD are aware of the complicated psychological issues generated by the perceived mismanagement of the bovine spongiform encephalopathy epidemic, which are often exacerbated by a delay or equivocation about diagnosis. Several families also choose experimental intracerebroventricular pentosan polysulfate therapy, which requires neurosurgery. In the context of these issues, the role of tonsillar biopsy is underemphasized by Heath et al and the criteria. In our experience of 60 biopsies, by far the largest series worldwide, tonsillar biopsy has 100% sensitivity and specificity, at any stage of the disease. Prion protein deposition in the tonsil can be patchy, and at least 20 germinal centers need to be examined. The number examined in 1 French case reported by Heath et al may not have been adequate to avoid a false-negative result. It is notable that of the 6 most recent patients suspected clinically of having vCJD in the United Kingdom, 3 did not meet epidemiological criteria for probable vCJD while alive. Two of these patients would have been misdiagnosed as sporadic CJD according to the updated clinical diagnostic criteria for sporadic Creutzfeldt-Jakob Disease criteria; typical vCJD was diagnosed at autopsy in both. In a third patient, with a heterozygous codon 129 genotype reported by Kaski et al, the pulvinar sign was not thought to be present by all neuroradiologists, and no tissue was examined. It is reasonable to expect that tonsillar biopsy may have made the correct diagnosis in each of these cases. Given experience with transfusion-associated secondary vCJD, vCJD prions are likely to be present in significant titer in human blood, a diagnostic blood test based on detection of the infectious agent is clearly possible in principle, and if technologically achieved, will necessitate a complete revision of how we approach diagnosis in this disease.
A total of 75,206 blood serum samples from dairy cattle and quarantined heifers was collected between 2001 and 2007 and analyzed for bovine leptospirosis by the microscopic agglutination test (MAT). Serovar Hardjo was used for testing of all sera, with the addition of 2 or 3 randomly chosen other serovars (Grippotyphosa, Icterohaemorrhagiae, Pomona, Bataviae, Canicola, and/or Saxcoebing). From the total number of sera tested, 1197 (1.59%) were serologically positive, with a decreasing tendency over the years of research. The most prevalent serovar was Pomona (1.32%), followed by Hardjo (0.52%) and Grippotyphosa (0.37%). The differences among the studied regions in terms of the distribution of serovars and seroprevalence values may be attributed to different farm management approaches and climatic conditions. It is believed that the decrease in seroprevalence toward the last years of investigation may be due to the application of permanent control strategies against leptospirosis and antibiotic therapy for all seropositive animals with an antibody titer equal to or higher than 1:100.
Nema pronađenih rezultata, molimo da izmjenite uslove pretrage i pokušate ponovo!
Ova stranica koristi kolačiće da bi vam pružila najbolje iskustvo
Saznaj više