Construction and Verification of Performance and Reliability Models

Over the last two decades formal methods have been extended towards performance and reliability evaluation. This paper tries to provide a rather intuitive explanation of the basic concepts and features in this area. Instead of striving for mathematical rigour, the intention is to give an illustrative introduction to the basics of stochastic models, to stochastic modelling using process algebra, and to model checking as a technique to analyse stochastic models

Left ventricle diastolic dysfunction in postmenopausal women with essential arterial hypertension

Мета дослідження: визначення особливостей діастолічної дисфункції міокарду лівого шлуночка у жінок хворих на артеріальну гіпертензію з клімактеричним синдромом в залежності від тяжкості перебігу клімаксу. Обстежено 120 жінок, хворих на гіпертонічну хворобу, в періоді постменопаузи від 1 до 5 років. Основну групу склали 90 пацієнток з проявами клімактеричного синдрому. За вираженістю сомато-вегетативних симптомів за шкалою MRS хворих розподілили на три групи: перша (0–5 балів); друга (6–8 балів) та третя (≥ 9 балів). Контрольну групу склали 30 жінок, хворих на гіпертонічну хворобу у постменопаузі без ознак клімактеричного синдрому. Виявлені достовірне зниження КДО ЛШ та ФВ, підвищення КСО ЛШ, ознаки гіпертрофії ЛШ в другій та третій групах, зниження амплітуди піку Е та підвищення амплітуди піку А в групах з більш тяжким перебігом клімаксу. Формування діастолічної дисфункції ЛШ у хворих з тяжким перебігом клімаксу підтверджується нижчою ранньою діастолічною швидкістю руху мітрального кільця та підвищеними показниками Е/ЕА, зростанням показників IVRT та DT. При дослідженні типу порушення релаксації міокарду у хворих першої групи та групи контролю спостерігали переважно нормальну діастолічну релаксацію ЛШ та порушення релаксації, у хворих другої та третьої груп переважали порушення релаксації та псевдонормальний тип, проте серед хворих третьої групи зустрічались хворі з діастолічною дисфункцією за рестриктивним типом. Таким чином, у жінок, хворих на гіпертонічну хворобу в ранньому постклімактеричному періоді виявлено зв'язок вираженості діастолічної дисфункції з тяжкістю перебігу клімактеричного синдрому; найбільші порушення діастолічної релаксації лівого шлуночку спостерігали в групах з тяжким та середньої важкості перебігом клімактеричного синдрому; основний тип діастолічної дисфункції, що спостерігався – порушення релаксації, проте в ряді випадків спостерігали псевдонормальний та рестриктивний типи.Цель исследования: определить особенности диастолической дисфункции миокарда левого желудочка у женщин, страдающих артериальной гипертензией с климактерическим синдромом в зависимости от тяжести течения климакса. Обследовано 120 женщин, страдающих гипертонической болезнью, в периоде постменопаузы от 1 до 5 лет. Основную группу составили 90 пациенток с проявлениями климактерического синдрома. По выраженности сомато-вегетативных симптомов по шкале MRS больных разделили на три группы: первая (0–5 баллов); вторая (6–8 баллов) и третья (≥ 9 баллов). Контрольную группу составили 30 женщин с гипертонической болезнью в постменопаузе без признаков климактерического синдрома. Выявлено достоверное снижение КДО ЛЖ и ФВ, повышение КСО ЛЖ, признаки гипертрофии ЛЖ во второй и третьей группах, снижение амплитуды пика Е и повышение амплитуды пика А в группах с более тяжелым течением климакса. Формирование диастолической дисфункции ЛЖ у больных с тяжелым течением климакса подтверждается более низкой ранней диастолической скоростью движения митрального кольца с ростом отношения Е/ЕА, показателей IVRT и DT. При исследовании типа нарушения релаксации миокарда у больных первой группы и группы контроля наблюдали преимущественно нормальную диастолическую релаксацию ЛЖ и нарушенную релаксацию. У больных второй и третьей групп преобладали нарушенная релаксация и псевдонормальный тип, среди больных третьей группы встречались больные с диастолической дисфункцией по рестриктивному типу. Таким образом, у женщин с гипертонической болезнью в раннем постклимактерическом периоде выявлена связь выраженности диастолической дисфункции с тяжестью течения климактерического синдрома; наиболее выраженные нарушения диастолической релаксации левого желудочка наблюдали в группах с тяжелым и средней тяжести течением климактерического синдрома; основной наблюдаемый тип диастолической дисфункции – нарушение релаксации, однако в ряде случаев наблюдали псевдонормальный и рестриктивный типы.To determine the characteristics of diastolic dysfunction of the left ventricular myocardium in women with arterial hypertension and menopausal syndrome, depending on the severity of menopause

Classification of Alzheimer’s disease from quadratic sample entropy of electroencephalogram

Currently accepted input parameter limitations in entropy-based, non-linear signal processing methods, for example, sample entropy (SampEn), may limit the information gathered from tested biological signals. The ability of quadratic sample entropy (QSE) to identify changes in electroencephalogram (EEG) signals of 11 patients with a diagnosis of Alzheimer's disease (AD) and 11 age-matched, healthy controls is investigated. QSE measures signal regularity, where reduced QSE values indicate greater regularity. The presented method allows a greater range of QSE input parameters to produce reliable results than SampEn. QSE was lower in AD patients compared with controls with significant differences (p < 0.01) for different parameter combinations at electrodes P3, P4, O1 and O2. Subject- and epoch-based classifications were tested with leave-one-out linear discriminant analysis. The maximum diagnostic accuracy and area under the receiver operating characteristic curve were 77.27 and more than 80%, respectively, at many parameter and electrode combinations. Furthermore, QSE results across all r values were consistent, suggesting QSE is robust for a wider range of input parameters than SampEn. The best results were obtained with input parameters outside the acceptable range for SampEn, and can identify EEG changes between AD patients and controls. However, caution should be applied because of the small sample size

Psychosomatic Aspects of Narcolepsy

1. After a brief discussion of the nature of psychosomatic illness and of sleep, the literature on narcolepsy was reviewed. The term narcolepsy was defined and its history discussed. 2. It was pointed out that, while most cases of narcolepsy were "idiopathic", there was much evidence suggesting an underlying pathophysiological disturbance probably in the region of the reticular activating system. 3. It was added that there was much evidence suggesting that emotional factors could precipitate if not engender the condition. There seemed to be no justification for regarding the condition as an hysterical one. 4. The literature on neurotic somnolence was discussed. The psychogenic hypersomnias were divided into two groups viz. (a) prolonged trance states in which sleep was probably intermittent. (b) shorter attacks of what was probably genuine sleep, rarely of more than a days duration provoked by extreme weariness in the face of severe neurotic conflicts. It was argued that both groups were quite distinct from true narcolepsy. In addition, much briefer spells of hysterical "sleep" (usually lasting only for minutes) were considered. Evidence was presented for these being trance states rather than physiological sleep. 5. Six narcoleptic cases of my own were then presented; these were contrasted with three of my cases of neurotic somnolence. All six narcoleptics showed excessive, intermittent and inappropriate drowsiness both clinically and in the EEG recordings. In four cases, the EEG was taken under hypoglycaemia and showed a definite diminution in the amount of drowsiness. It was argued that this might have been due to central liberation of adrenaline with stimulation of the adrenaline-sensitive part of the reticular activating system. These four patients also showed mild abnormalities of the Exton Rose glucose tolerance test. Clinically all six cases showed some evidence of emotional disturbance in childhood prior to the onset of narcolepsy, and all showed some personality change after the onset of narcolepsy* Psychological tests were definitely abnormal in five of the cases and showed some slight disturbance in the sixth. In five cases, the symptomatology was markedly aggravated by emotional upset and in particular some relationship was noted between the symptoms and inhibited aggression. The three neurotics did not show typical EEG or clinical features of narcolepsy. Only one showed even light drowsiness in the EEG and this was only occasionally present at a time when he could not be roused. Examination of his reflexes did not support the impression that this was a true sleep. 6. One of ray narcoleptic patients showed paranoid schizophrenia arising in intimate association with the sleep hallucinosis. Such cases are extremely rare. The literature was reviewed and the condition discussed. 7. The EEG in four recordings of cataplexy showed no specific change. Some drowsiness appeared. 8. It would be correct to call narcolepsy a psychosomatic Illness. Both somatic and psychological factors are of importance. The latter are important in two ways: (a) They may greatly increase the symptomatology. (b) They influence the way in which the patient handles his illness. It is essential to treat the patient rather than the disease and in many cases psychotherapy is indicated

Some 19th Century Visitors to Caves in Peninsular Malaysia

Človek je poznal jame v Maleziji že od predzgodovinskih časov, ko jih je uporabljal kot zatočišča, taborišča ali skrivališča. Najstarejša taka sled s polotoške Malezije je človeško okostje, staro 11.000 let. Prvi zapisi o obiski teh jam pa izvirajo šele iz 19. stoletja, ko so jih obiskovali predvsem Evropejci za zabavo, iz vedoželjnosti ali zaradi raziskovanja. Z raziskavami so v glavnem pričeli britanski kolonialni častniki, nastanjeni v Malaji, v 80-tih letih 19. stoletja. Leta 1878 so "odkrili" jame Batu in z njimi seznanili Evropejce. V prispevku so našteti nekateri izmed teh obiskovalcev ter so opisane zgodnje raziskave.Malaysian caves have been known to man since prehistoric times, when they were used as shelters, campsites or places of refuge. The oldest remains found in Peninsular Malaysia are a human skeleton dated at 11.000 years old. But it wasnot until the 19th century that records appear of caves being visited, generally by European visitors for recreation, curiosity or research. Research generally began in the 1880's, mainly by British colonial officers stationed in Malaya. The caves at Batu Caves were ˝discovered˝ and made known to Europeans in 1878. This article lists some of the visitors and describes some of the early research

Characterising seizures in anti-NMDA-receptor encephalitis with dynamic causal modelling

We characterised the pathophysiology of seizure onset in terms of slow fluctuations in synaptic efficacy using EEG in patients with anti-N-methyl-d-aspartate receptor (NMDA-R) encephalitis. EEG recordings were obtained from two female patients with anti-NMDA-R encephalitis with recurrent partial seizures (ages 19 and 31). Focal electrographic seizure activity was localised using an empirical Bayes beamformer. The spectral density of reconstructed source activity was then characterised with dynamic causal modelling (DCM). Eight models were compared for each patient, to evaluate the relative contribution of changes in intrinsic (excitatory and inhibitory) connectivity and endogenous afferent input. Bayesian model comparison established a role for changes in both excitatory and inhibitory connectivity during seizure activity (in addition to changes in the exogenous input). Seizures in both patients were associated with a sequence of changes in inhibitory and excitatory connectivity; a transient increase in inhibitory connectivity followed by a transient increase in excitatory connectivity and a final peak of excitatory-inhibitory balance at seizure offset. These systematic fluctuations in excitatory and inhibitory gain may be characteristic of (anti NMDA-R encephalitis) seizures. We present these results as a case study and replication to motivate analyses of larger patient cohorts, to see whether our findings generalise and further characterise the mechanisms of seizure activity in anti-NMDA-R encephalitis