Estimation of the parameters for non-stationary time series with long memory and heavy tails using weak dependence condition

Wnioskowanie statystyczne dla nieznanych rozkładów statystyk lub estymatorów można oprzeć na rozkładach asymptotycznych. Niestety, w przypadku danych zależnych, takie procedury statystyczne są¸ niejednokrotnie nieefektywne. Różne są¸ tego przyczyny, np. zbyt ma la liczba danych, nieznana postać rozkładu asymptotycznego, zbyt wolna zbieżność do rozkładu asymptotycznego. Od początku lat osiemdziesiątych ubiegłego wieku intensywnie prowadzone są badania nad rozwojem tzw. metod resamplingowych. Za pomocą tychże metod można bezpośrednio przybliżać nieznane rozkłady statystyk i estymatorów. Idea resamplingu jest prosta. Obliczamy replikacje estymatora i z tych replikacji wyznaczamy rozkład empiryczny tzw. rozkład resamplingowy. Problem, z którym trzeba się zmierzyć badając procedury resamplingowe to ich zgodność, tzn. czy rozkład resamplingowy jest bliski prawdziwemu rozkładowi ? Metod resamplingowych jest wiele. Ich zgodność w przypadku obserwacji niezależnych została dogłębnie zbadana. Przypadek danych stacjonarnych ze swoistą strukturą zależności tzn. silnie mieszających także został zbadany. Przedmiotem intensywnych prac badaczy był również resampling dla niestacjonarnych szeregów czasowych ze specyficzną formą niestacjonarności tzn. okresowych i prawie okresowych. Ostatnie badania nad metodami resamplingowymi koncentrują się głównie na szeregach czasowych ze zdefiniowana¸ przez Paula Doukhana słabą zależnością. W niniejszej pracy został przedstawiony model dla szeregów czasowych, które maja¸ bardzo specyficzne własności tzn.: posiadają długa¸ pamięć, ciężkie ogony (stabilne lub GED) oraz strukturę okresową. Taki model może mieć naturalne zastosowanie w wielu dziedzinach np.: energetyce, wibromechanice, telekomunikacji, klimatologii jak również w ekonomii. Celem pracy jest pokazanie twierdzeń dotyczących zgodności estymatora jednej z metod resamplingowych dla funkcji średniej we wspomnianych powyżej szeregach czasowych. Okazuje się, że jedyną metodą resamplingową, którą można zastosować do danych z długą pamięcią jest subsampling. Polega ona na wyborze z obserwacji wszystkich możliwych podciągów o pewnej długości i wyznaczaniu estymatora na tych podciągach. W pracy sformułowano i udowodniono centralne twierdzenia graniczne, niezbędne do udowodnienia zgodności subsamplingu. Ponadto przedstawiony został przegląd dotychczasowych rezultatów dotyczących metod resamplingowych w szeregach czasowych

Eye movements in essential tremor patients with parkinsonian and cerebellar signs

Apart from intention tremor essential tremor (ET) patients may display other cerebellar signs, like dysmetria or tandem gait disturbances as well as parkinsonian signs like resting tremor, cogwheel sign, subtle bradykinesia. Previous reports claimed the occurrence of the eye movement abnormalities characteristic for dysfunction of cerebellar dorsal vermis in ET patients with concomitant cerebellar signs. There are no previous reports evaluating the eye movement abnormalities in ET patients with concomitant parkinsonian signs. The objective of this study was to determine the relationship between the occurrence of parkinsonian and cerebellar signs and the oculomotor abnormalities in ET patients. Method Fifty ET patients including 6 (12.0%) patients with concomitant parkinsonian signs (ET-P), 20 (40.0%) patients with cerebellar signs (ET-C), 7 (14.0%) with mixed parkinsonian and cerebellar signs (ET-M), 17 (34.0%) patients with the only tremor (ET-T) together with 42 healthy controls were included to the study. Reflexive, pace-induced and cued saccades were recorded using Saccadometer Advanced. Smooth pursuit and fixation were tested using EOG. Results Latency of pace-induced saccades was significantly longer in ET-C and ET-M patients compared to ET-T and ET-P patients. Latency of cued saccades was significantly longer in ET-M patients compared to ET-T. There were no significant differences of the eye movement parameters between ET-P patients compared to ET-T patients. Conclusion In ET patient with concomitant cerebellar signs prolonged volitional saccades latency was detected. There are no particular differences in the eye movements in ET patients with concomitant parkinsonian signs compared to ET patients without concomitant signs

Eye movements in essential tremor patients with parkinsonian and cerebellar signs

Apart from intention tremor essential tremor (ET) patients may display other cerebellar signs, like dysmetria or tandem gait disturbances as well as parkinsonian signs like resting tremor, cogwheel sign, subtle bradykinesia. Previous reports claimed the occurrence of the eye movement abnormalities characteristic for dysfunction of cerebellar dorsal vermis in ET patients with concomitant cerebellar signs. There are no previous reports evaluating the eye movement abnormalities in ET patients with concomitant parkinsonian signs. The objective of this study was to determine the relationship between the occurrence of parkinsonian and cerebellar signs and the oculomotor abnormalities in ET patients. Method: Fifty ET patients including 6 (12.0%) patients with concomitant parkinsonian signs (ET-P), 20 (40.0%) patients with cerebellar signs (ET-C), 7 (14.0%) with mixed parkinsonian and cerebellar signs (ET-M), 17 (34.0%) patients with the only tremor (ET-T) together with 42 healthy controls were included to the study. Reflexive, pace-induced and cued saccades were recorded using Saccadometer Advanced. Smooth pursuit and fixation were tested using EOG. Results: Latency of pace-induced saccades was significantly longer in ET-C and ET-M patients compared to ET-T and ET-P patients. Latency of cued saccades was significantly longer in ET-M patients compared to ET-T. There were no significant differences of the eye movement parameters between ET-P patients compared to ET-T patients. Conclusion: In ET patient with concomitant cerebellar signs prolonged volitional saccades latency was detected. There are no particular differences in the eye movements in ET patients with concomitant parkinsonian signs compared to ET patients without concomitant signs

The effects of physiotherapy with PNF concept on gait and balance of patients with Huntington's disease : pilot study

Background and purpose Huntington's disease (HD) is a neurodegenerative, progressive disorder of the central nervous system which causes significant gait and balance disturbances. This is a pilot study which aims to determine the effects of a physiotherapy programme with use of Proprioceptive Neuromuscular Facilitation (PNF) on gait and balance in HD patients. Material and methods 30 HD patients aged 21-60 with genetically confirmed diagnosis participated in the study. Participants followed a 3-week-long PNF-based physiotherapy programme. Gait and balance were evaluated twice in each participant: first at baseline and then after the course of physiotherapy. The following methods were used for gait disturbances: Tinetti Gait Assessment Tool, Up and Go Test, Timed Walking Tests for 10m and 20m (TWT10m, TWT20m). Balance was assessed with use of Berg Balance Scale, Pastor Test and Functional Reach Test. Results There was a significant improvement in all measures of balance and gait. Conclusion PNF-based physiotherapy is effective and safe in HD patients

The effects of physiotherapy with PNF concept on gait and balance of patients with Huntington's disease – pilot study

Background and purpose Huntington's disease (HD) is a neurodegenerative, progressive disorder of the central nervous system which causes significant gait and balance disturbances. This is a pilot study which aims to determine the effects of a physiotherapy programme with use of Proprioceptive Neuromuscular Facilitation (PNF) on gait and balance in HD patients. Material and methods 30 HD patients aged 21–60 with genetically confirmed diagnosis participated in the study. Participants followed a 3-week-long PNF-based physiotherapy programme. Gait and balance were evaluated twice in each participant: first at baseline and then after the course of physiotherapy. The following methods were used for gait disturbances: Tinetti Gait Assessment Tool, Up and Go Test, Timed Walking Tests for 10m and 20m (TWT10m, TWT20m). Balance was assessed with use of Berg Balance Scale, Pastor Test and Functional Reach Test. Results There was a significant improvement in all measures of balance and gait. Conclusion PNF-based physiotherapy is effective and safe in HD patients

The influence of motor ability rehabilitation on temporal-spatial parameters of gait in Huntington's disease patients on the basis of a three-dimensional motion analysis system: An experimental trial

Objective There is no existing standard, evidence-based, scientific model for motor ability improvement in Huntington's Disease (HD) patients aimed at maintaining independent gait for as long as possible, or performing activities of daily living, the effectiveness of which would be supported by the results of studies using objective research tools. Under these circumstances, the aim of this study was to analyze the influence of motor ability rehabilitation on the spatial-temporal parameters of gait in HD patients. Design It was an experimental trial. The studied group consisted of 30 patients (17 women and 13 men) with HD. In hospital conditions, the patients participated in the 3-week motor ability l rehabilitation programme tailored to individual needs. The study group was tested using the Vicon 250 three-dimensional gait analysis system before and after the physical exercise programme. Results Walking speed after therapy increased for the left lower limb from 1.06 (SD 0.24) [m/s] to 1.21 (SD 0.23) [m/s], and for the right lower limb from 1.07 (SD 0.25) [m/s] to 1.20 (SD 0.25) [m/s]. The cycle length increased after the applied therapy for the left lower limb from 1.17 (SD 0.20) [m] to 1.23 (SD 0.19) [m]. Conclusion The three-week motor ability rehabilitation programme positively influences spatial-temporal gait parameters in HD patients

Przyczyny i konsekwencje upadków w chorobie Parkinsona – badanie prospektywne

Background and purpose Falls are common events in Parkinson disease (PD) but only a few prospective studies have focused on causes and consequences of falls in PD patients. The aim of the study was prospective analysis of direct causes and consequences of falls in PD patients in comparison to the control group. Material and methods One hundred PD patients and 55 age-matched controls were enrolled in the study. The diagnostic workup in all patients included neurological examination, Unified Parkinson's Disease Rating Scale, magnetic resonance imaging, electroencephalography, ultrasonography, otolaryngological, ophthalmological and autonomic function examination. During 12 months of follow-up, falls were registered in both groups, direct causes were classified according to the St. Louis and Olanow classification, and consequences were established. Results Falls occurred in 54% of PD patients and in 18% of control subjects. Analysis of direct causes of falls revealed that sudden falls were the most common (31%), followed by episodes of freezing and festination (19.6%), neurological and sensory disturbances (mostly vertigo) (12%), environmental factors (12%), postural instability (11%), orthostatic hypotension (4%), and severe dyskinesia (3.6%); 6.19% of falls were unclassified; 22% of patients had the same etiology of subsequent falls. In PD patients, intrinsic factors were dominant, whereas in the control group intrinsic and extrinsic factors occurred with the same frequency. Every third fall intensified fear of walking. 34% of falls caused injuries; among them bruises of body parts other than the head were most frequent. Conclusions Intrinsic factors are the most common causes of falls in PD. Every third fall intensifies fear of walking and causes injuries.Wstęp i cel pracy Upadki są częstymi objawami choroby Parkinsona (ChP). Dotychczas jednak tylko w kilku badaniach oceniano przyczyny i konsekwencje upadków w ChP. Celem badania była prospektywna analiza przyczyn bezpośrednich oraz konsekwencji upadków u pacjentów z ChP w porównaniu z grupą kontrolną. Materiał i metody Do badania zostało włączonych 100 chorych na ChP oraz 55 dobranych pod względem wieku osób z grupy kontrolnej. U wszystkich chorych przeprowadzono badanie neurologiczne, ocenę za pomocą Unified Parkinson's Disease Rating Scale, badanie za pomocą rezonansu magnetycznego, elektroencefalografię i ultrasonografię, badanie otolaryngologiczne i okulistyczne oraz badanie czynności autonomicznych. Podczas 12-miesięcznej obserwacji upadki rejestrowano w obu badanych grupach. Przyczyny bezpośrednie upadków podzielono zgodnie z klasyfikacją St. Louis i Olanowa, określano także konsekwencje upadków. Wyniki Upadki wystąpiły u 54% chorych na ChP i 18% osób z grupy kontrolnej. Najczęstsze były upadki nagłe (31%), następnie epizody zamrożeń i dreptania (19,6%), zaburzenia neurologiczne i czuciowe (zawroty głowy) (12%), czynniki zewnętrzne (12%), niestabilność postawy (11%), niedociśnienie ortostatyczne (4%), nasilone dyskinezy (3,6%). Upadki niesklasyfikowane stanowiły 6,19%. U 22% chorych etiologia kolejnych upadków była jednakowa. U chorych na ChP dominowały czynniki wewnętrzne, a w grupie kontrolnej częstości czynników wewnętrznych i zewnętrznych były podobne. Co trzeci upadek nasilał lęk przed chodzeniem, 34% upadków powodowało obrażenia, najczęściej sduczenia. Wnioski Czynniki wewnętrzne są najczęstszymi przyczynami upadków w ChP. Co trzeci upadek nasila lęk przed chodzeniem oraz powoduje obrażenia

Physical activity, psychological and functional outcomes in non-ambulatory stroke patients during Rehabilitation : a pilot study

Despite the extensive literature on stroke rehabilitation, there are few studies that comprehensively show non-ambulatory stroke patients. The aim of the study was to explore the dynamics of the change in physical activity (PA), psychological and functional outcomes, and the correlation between them in non-ambulatory patients during early in-patient post-stroke rehabilitation. Measurements were taken on 21 participants at the beginning of and 6 weeks post-conventional rehabilitation with the Barthel Index (BI), Berg Balance Scale (BBS), Trunk Control Test (TCT), Stroke Impact Scale (SIS), General Self-Efficacy Scale, Stroke Self-Efficacy Questionnaire (SSEQ), the original scale of belief in own impact on recovery (BiOIoR), Hospital Anxiety and Depression Scale, Acceptance of Illness Scale and when the patient could walk—Time Up & Go and 6 Minute Walk Test. Daily PA was assessed over 6 weeks using a Caltrac accelerometer. Only outcomes for BI, BBS, TCT, SIS, and SSEQ significantly improved 6 weeks post-rehabilitation. PA energy expenditure per day significantly increased over time (p < 0.001; effect size = 0.494), but PA only increased significantly up to the third week. PA change was correlated with BiOIoR post-treatment. Self-efficacy in self-management mediated improvement in SIS. The BiOIoR and confidence in self-management could be important factors in the rehabilitation process

Causes and consequences of falls in Parkinson disease patients in a prospective study

Background and purpose: Falls are common events in Parkinson disease (PD) but only a few prospective studies have focused on causes and consequences of falls in PD patients. The aim of the study was prospective analysis of direct causes and consequences of falls in PD patients in comparison to the control group. Material and methods: One hundred PD patients and 55 age-matched controls were enrolled in the study. The diagnostic workup in all patients included neurological examination, Unified Parkinson’s Disease Rating Scale, magnetic resonance imaging, electroencephalography, ultrasonography, otolaryngological, ophthalmological and autonomic function examination. During 12 months of follow-up, falls were registered in both groups, direct causes were classified according to the St. Louis and Olanow classification, and consequences were established. Results: Falls occurred in 54% of PD patients and in 18% of control subjects. Analysis of direct causes of falls revealed that sudden falls were the most common (31%), followed by episodes of freezing and festination (19.6%), neurological and sensory disturbances (mostly vertigo) (12%), environmental factors (12%), postural instability (11%), orthostatic hypotension (4%), and severe dyskinesia (3.6%); 6.19% of falls were unclassified; 22% of patients had the same etiology of subsequent falls. In PD patients, intrinsic factors were dominant, whereas in the control group intrinsic and extrinsic factors occurred with the same frequency. Every third fall intensified fear of walking. 34% of falls caused injuries; among them bruises of body parts other than the head were most frequent. Conclusions: Intrinsic factors are the most common causes of falls in PD. Every third fall intensifies fear of walking and causes injuries

Model DPSIR jako narzędzie efektywnego zarządzania jakością powietrza

Decyzje i działania (odpowiedzi) podejmowane na podstawie pełnej i wiarygodnej analizy czynników sprawczych, presji, zmiany parametrów stanu i ich wpływu na środowisko, społeczeństwo oraz gospodarkę mogą z dużym prawdopodobieństwem w długoterminowej perspektywie przynieść pożądane efekty. W artykule opisano model DPSIR (driving forces, pressures, state, impact, responses; odpowiednio: czynniki sprawcze, presje, stan, wpływ, odpowiedzi) służący do szczegółowej analizy interakcji pomiędzy czynnikami antropogenicznymi a środowiskiem. Tworzony model DPSIR będzie skutecznym narzędziem do zarządzania jakością powietrza. W artykule przedstawiono badania prowadzone w Akademii Górniczo-Hutniczej, które zostaną wykorzystane jako jedne z wielu danych wejściowych w powstającym modelu DPSIR. Opracowywany model będzie jednym ze składowych zaawansowanego narzędzia tworzonego na AGH, w ramach Obserwatorium Transformacji Energetycznej (OTE), które umożliwi przygotowanie rekomendacji optymalnych działań dotyczących realizacji polityki energetycznej i poprawy jakości powietrza w Polsce