Możliwości predykcji wstrząsów na podstawie analizy zjawisk maksymalnych emisji sejsmicznej w systemie INGEO

Predicting the time of rock bursts in the INGEO system is based on the analysis of seismic emission registered in a seismic-acoustic system. Emission signals are generated by rock mass fracturing due to mining exploitation. Such emission is characterized by huge activity of different phenomena which enables to carry out a correct statistical analysis with the use of the hazard method, achieving suitably high resolution of interpretation results. The hazard method is based on the analysis of maxmal phenomena, i.e. phenomena of maximal energy. The use of this method allows to eliminate disturbances to a large extent and, at the same time, enables to assess the probability of high-energy phenomena (rock bursts). The hazard analysis is conducted on the basis of two essential qualities of seismic emission, such as energy of phenomena and intervals between successive phenomena. These qualities are random variables of statistical distribution described by the Weibull model. Using this model one can estimate the parameters of statistical distribution of those qualities which are the basis to determine hazard parameters. The analysis is conducted based on measurement data collected from the T window, i.e. time interval measured by hours. The window is moved with the d step and the calculations are repeated. The hazard parameters were used to define the risk function FWt(QE,T) which is the measure of rock bursts hazard. This function depends on real time t which is determined as the time of the T window right edge. It is also the basis to work out rock burst hazard criteria. It is important to note that the moment a rock burst occurs is a random variable and can be determined with the accuracy of its confidence interval, with certain probability.Predykcja czasu wystąpienia wstrząsów w systemie INGEO oparta jest na analizie emisji sejsmicznej rejestrowanej w systemie sejsmoakustycznym. Sygnały emisji są generowane pękaniem górotworu wywołanym eksploatacją. Emisja taka charakteryzuje się dużą aktywnością zjawisk, która umożliwia prowadzenie poprawnej analizy statystycznej metodą hazardu, uzyskując również odpowiednio wysoką rozdzielczość wyników interpretacji. Metoda hazardu oparta jest na analizie zjawisk maksymalnych, czyli zjawisk o maksymalnej energii. Zastosowanie tej metody daje znaczną eliminację zakłóceń, a jednocześnie umożliwia ocenę prawdopodobieństwa wystąpienia zjawisk wysokoenergetycznych (wstrząsów). Analiza hazardu realizowana jest na podstawie dwóch podstawowych cech emisji sejsmicznej, a mianowicie: energii zjawisk, oraz odstępów czasu między kolejnymi zjawiskami. Cechy te są zmiennymi losowymi o rozkładzie statystycznym, który jest opisywany modelem Weibull`a. Na podstawie tego modelu prowadzona jest estymacja parametrów rozkładu statystycznego tych cech, które stanowią podstawę do wyznaczania parametrów hazardu. Analiza realizowana jest w oparciu o dane pomiarowe pobierane z okna T, czyli przedziału czasu rzędu godzin. Okno to jest przesuwane z krokiem d i powtarzane są obliczenia. Wykorzystując parametry hazardu zdefiniowano funkcję ryzyka FWt(QE,T), będącą miarą zagrożenia wystąpieniem wstrząsów. Funkcja ta jest zależna od czasu realnego t, który jest określony, jako czas prawego brzegu okna T. Stanowi ona podstawę do opracowania kryteriów stanu zagrożenia tąpaniami, jak również jej przebieg może być wykorzystany do oceny czasu wystąpienia wstrząsów. Należy podkreślić, że moment wystąpienia wstrząsu jest zmienną losową i może być wyznaczony z dokładnością do swojego przedziału ufności, z określonym prawdopodobieństwem

Is there the gap in public health literature in Europe?

Introduction and objective: The growing expectations for the effectiveness of public health increase the demand for scientific literature, concerning research, reviews and other forms of information. The bibliographic databases are of crucial importance for researchers and policy makers. The objective of this study is to estimate the supply of scientific literature related to public health in selected European countries, which are available to a wide range of users. Materials and methods: Analysis of the number of bibliographic records on topics related to public health was based on searches in Ovid MEDLINE ( R) in May and June 2011. According to MeSH terms, 11 keywords and names of 13 European countries were used in the search. Publications from the years 2001–2010 were analyzed. A number of publications indexed under ‘public health’, and related to selected countries were compared with the size of the population of those countries, GDP, total expenditure on health and burden of disease (DALYS’s). Results: The most popular topic was ‘health policy’, whereas the topics ‘occupational health’ and ‘environmental health’ were less prevalent. There were no significant changes in the number of publications in 2001–2010. The number of articles indexed under ‘public health’ had significant positive correlation with national GDP, expenditure on health and population size, and negative with DALY’s. Conclusions: According to the criteria accepted in this study, the Nordic countries – Finland, Sweden and Norway – were very productive in this respect. Poland and other Central European Countries were less productive

Lamivudine and alpha interferon combination treatment of patients with chronic hepatitis B infection: a randomised trial

BACKGROUND, AIM, AND METHODS—Alpha interferon is the generally approved therapy for HBe antigen positive patients with chronic hepatitis B, but its efficacy is limited. Lamivudine is a new oral nucleoside analogue which potently inhibits hepatitis B virus (HBV) DNA replication. To investigate the possibility of an additive effect of interferon-lamivudine combination therapy compared with interferon or lamivudine monotherapy, we conducted a randomised controlled trial in 230 predominantly Caucasian patients with hepatitis B e antigen (HBeAg) and HBV DNA positive chronic hepatitis B. Previously untreated patients were randomised to receive: combination therapy of lamivudine 100 mg daily with alpha interferon 10 million units three times weekly for 16 weeks after pretreatment with lamivudine for eight weeks (n=75); alpha interferon 10 million units three times weekly for 16 weeks (n=69); or lamivudine 100 mg daily for 52 weeks (n=82). The primary efficacy end point was the HBeAg seroconversion rate at week 52 (loss of HBeAg, development of antibodies to HBeAg and undetectable HBV DNA).
RESULTS—The HBeAg seroconversion rate at week 52 was 29% for the combination therapy, 19% for interferon monotherapy, and 18% for lamivudine monotherapy (p=0.12 and p=0.10, respectively, for comparison of the combination therapy with interferon or lamivudine monotherapy). The HBeAg seroconversion rates at week 52 for the combination therapy and lamivudine monotherapy were significantly different in the per protocol analysis (36% (20/56) v 19% (13/70), respectively; p=0.02). The effect of combining lamivudine and interferon appeared to be most useful in patients with moderately elevated alanine aminotransferase levels at baseline. Adverse events with the combination therapy were similar to interferon monotherapy; patients receiving lamivudine monotherapy had significantly fewer adverse events.
CONCLUSIONS—HBeAg seroconversion rates at one year were similar for lamivudine monotherapy (52 weeks) and standard alpha interferon therapy (16 weeks). The combination of lamivudine and interferon appeared to increase the HBeAg seroconversion rate, particularly in patients with moderately elevated baseline aminotransferase levels. The potential benefit of combining lamivudine and interferon should be investigated further in studies with different regimens of combination therapy.


Keywords: chronic hepatitis B; hepatitis B virus; nucleoside analogue; lamivudine; alpha interferon; combination therapy; HBeAg seroconversio