Seismic hazard assessment in the Northern Aegean Sea (Greece) through discrete Semi-Markov modeling.

Οι ημι-Μαρκοβιανές αλυσίδες χρησιμοποιούνται για τη μελέτη της σεισμικότητας στο Βόρειο  Αιγαίο.  Η  βασική  τους  διαφορά  από  τις  Μαρκοβιανές  αλυσίδες  είναι  ότι επιτρέπουν  μια  οποιαδήποτε  αυθαίρετη  κατανομή  για  τους  χρόνους  παραμονής (χρόνοι μεταξύ διαδοχικών σεισμών). Υποθέτουμε ότι η χρονοσειρά των σεισμών που έχουν  γίνει  στο  Βόρειο  Αιγαίο  αποτελεί  μια  διακριτή  ημι-Μαρκοβιανή  αλυσίδα. Θεωρείται ότι οι χρόνοι παραμονής ακολουθούν γεωμετρικές ή διακριτές κατανομές Weibull. Πρώτα ταξινομήθηκαν τα δεδομένα σε δυο κατηγορίες, όπου κατάσταση 1: Μέγεθος 6.5 -7 και κατάσταση 2 Μέγεθος>7, και στη συνέχεια σε τρεις κατηγορίες, όπου   κατάσταση 1: μέγεθος 6.5 -6.7,   κατάσταση 2 :   Μέγεθος 6.8 -7.1   και κατάσταση 3 : Μέγεθος 7.2 -7.4 . Εκτιμήθηκαν οι παράμετροι των συναρτήσεων πιθανότητας των χρόνων  παραμονής  και  υπολογίστηκαν  οι  πίνακες  πυρήνες  της  ημι-Μαρκοβιανής αλυσίδας για όλες τις παραπάνω περιπτώσεις. Έγινε σύγκριση των πινάκων πυρήνων και   προέκυψαν συμπεράσματα για  τη μελλοντική σεισμική επικινδυνότητα στην υπό μελέτη περιοχή.Semi-Markov  chains  are  used  for  studying  the  evolution  of  seismicity  in  the Northern Aegean Sea (Greece). Their main difference from the Markov chains is that   they  allow the sojourn times (i.e. the time between successive earthquakes), to follow any arbitrary distribution. It is assumed that the time series of earthquakes that  occurred  in  Northern  Aegean  Sea  form  a  discrete  semi-Markov  chain. The probability law of the sojourn times, is considered to be the geometric distribution or   the   discrete  Weibull  distribution. Firstly,  the  data  are  classified  into  two categories that is, state 1: Magnitude 6.5  -7 and state 2 Magnitude>7, and secondly into three categories , that is    state 1: Magnitude 6.5-6.7, state 2: Magnitude 6.8-7.1 and state 3: Magnitude 7.2-7.4 . This methodology is followed in order to obtain more accurate results and find out whether there exists an impact of the different classification on the results. The parameters of the probability laws of the sojourn times are estimated and the semi-Markov kernels are  evaluated for all the above cases  .  The  semi-Markov  kernels  are  compared and  the   conclusions  are  drawn relatively to future seismic hazard in the area under study

Nasal IL-13 production identifies patients with late phase allergic responses

BACKGROUND: There is limited knowledge on how local cytokine secretion patterns after nasal allergen challenge correlate with clinical symptoms especially with regards to the "late allergic response" (LAR) which occurs in approximately 40-50% of allergic patients. OBJECTIVE: In this study we aimed to characterise the immunological and clinical nasal responses to birch pollen allergen challenge with a special focus on the LAR. METHODS: In this randomised double-blinded placebo-control trial, birch pollen allergic participants were challenged with pollen extract (n=20) or placebo (n=10) on three consecutive days. On days one and three nasal secretions were collected at selected time points over a 24h time course for the measurement of 33 inflammatory mediators. Clinical responses were determined through subjective symptom scores and objective nasal airflow measurements. RESULTS: Provoked participants had significantly greater clinical responses and showed significant increases in tryptase and sST2 within minutes compared to placebo. Eight out of 20 provoked participants displayed high IL-13 levels 2-8 hours after allergen provocation. This group also showed significant changes in clinical parameters, with a secondary drop in nasal airflow measured by peak nasal inspiratory flow and increased symptoms of nasal obstruction which significantly differed from IL-13 non responders at 6 hours. CONCLUSION: IL-13 response status correlates with cytokine and clinical responses in the late phase after allergen provocation

Elevated IgA antiphospholipid antibodies in healthy pregnant women in Sudan but not Sweden, without corresponding increase in IgA anti-β2 glycoprotein I domain 1 antibodies

Objective: The role of antiphospholipid antibodies (aPL) during apparently normal pregnancy is still unclear. IgA aPL are prevalent in populations of African origin. Our aim was to measure all isotypes of anticardiolipin (anti-CL) and anti–β2 glycoprotein I (anti-β2GPI) in healthy pregnant and non-pregnant women of different ethnicities. Methods: Healthy Sudanese pregnant women (n = 165; 53 sampled shortly after delivery), 96 age-matched Sudanese female controls and 42 healthy pregnant and 249 non-pregnant Swedish women were included. IgA/G/M anti-CL and anti-β2GPI were tested at one time point only with two independent assays in Sudanese and serially in pregnant Swedes. IgA anti-β2GPI domain 1 and as controls IgA/G/M rheumatoid factor (RF), IgG anti–cyclic citrullinated peptide 2 (anti-CCP2) and anti–thyroid peroxidase (anti-TPO) were investigated in Sudanese females. Results: Pregnant Sudanese women had significantly higher median levels of IgA anti-CL, IgA anti-β2GPI (p < 0.0001 for both antibodies using two assays) and IgM anti-β2GPI (both assays; p < 0.0001 and 0.008) compared with non-pregnant Sudanese. IgA anti-CL and anti-β2GPI occurrence was increased among Sudanese pregnant women compared with national controls. No corresponding increase during pregnancy was found for IgA anti-β2GPI domain 1 antibodies. Both IgG anti-CL and IgG control autoantibodies decreased during and directly after pregnancy among Sudanese. Serially followed Swedish women showed no changes in IgA aPL, whereas IgG/M anti-CL decreased. Conclusions: IgA aPL are increased in Sudanese but not in Swedish women, without corresponding increase in IgA domain 1. Whether due to ethnicity and/or environmental influences the occurrence of IgA aPL during Sudanese pregnancies, and its clinical significance, is yet to be determined

High IgA antiphospholipid autoantibodies in healthy Sudanese explain the increased prevalence among Sudanese compared to Swedish systemic lupus erythematosus patients

Objectives: IgA antiphospholipid antibodies (aPL) are prevalent in systemic lupus erythematosus (SLE) patients of African American, Afro-Caribbean and South African origin. Nevertheless, data from North Africa are lacking, and most studies use manufacturer-suggested cut-offs based on Caucasian controls. Therefore, we compared aPL isotypes in Sudanese and Swedish SLE patients using nation-based cut-offs. Methods: Consecutive SLE patients and age- and sex-matched controls from Sudan (N = 115/106) and Sweden (N = 340/318) were included. All patients fulfilled the 1982 American College of Rheumatology SLE classification criteria. Antiphospholipid syndrome-related events were obtained from patients' records. IgA/G/M anticardiolipin and anti-beta(2) glycoprotein I (beta(2) GPI) were analysed with two independent assays. IgA anti-beta(2) GPI domain 1 (D1) was also investigated. Manufacturers' cut-offs and the 95th and 99th percentile cut-offs based on national controls were used. Results: Sudanese patients and controls had higher levels and were more often positive for IgA aPL than Swedes when using manufacturers' cut-offs. In contrast, using national cut-offs, the increase in IgA aPL among Sudanese patients was lost. Occurrence of IgA anti-D1 did not differ between the countries. Venous thromboses were less common among Sudanese patients and did not associate with aPL. No clinical associations were observed with IgA anti-beta(2) GPI in Sudanese patients. Thromboses in Swedes were associated with IgG/M aPL. Fetal loss was associated with aPL in both cohorts. Conclusions: IgA anti-beta(2) GPI prevalence was higher among Sudanese compared to Swedish patients when manufacturers' cut-offs were used. This situation was reversed when applying national cut-offs. Anti-D1 was not increased in Sudanese patients. Previous studies on populations of African origin, which demonstrate a high prevalence of IgA aPL positivity, should be re-evaluated using a similar cut-off approach