Earthquakes trigger other earthquakes and build up clusters in space and time that in turn create a bias in seismic catalogues. Therefore, declustering is considered as a prerequisite in seismic ...studies, particularly for probabilistic seismic hazard analysis, not only to eliminate the bias but also to decouple mainshocks and triggered events. However, a declustering process is not a straightforward task due to the complex nature of earthquake phenomena. There exist several declustering methods that mostly employ subjective rules to distinguish between background seismicity and offsprings. Eventually, the final declustered catalogues usually deviate significantly according to the employed method. This issue is raising some concerns, such as how to select the most suitable declustering algorithm, or to assess how this selection affects seismic hazard assessment. In consequence, the main goal of this paper is to quantify the sensitivity of seismic hazard assessments to different declustering techniques. Accordingly, the recently compiled Turkish earthquake catalogue was declustered by making use of three declustering algorithms. A total of six declustered catalogues, two catalogues per method, one by implementing the default input parameters, and one by altering the free input parameters of the employed methods, were produced. The clusters of selected earthquakes were studied in terms of the spatial–temporal distribution of earthquake sequences. A sensitivity analysis was conducted through the major steps of seismic hazard assessment for Istanbul metropolitan city. The seismicity of Istanbul and surroundings was modeled on the basis of four areal source zones. Comparative studies showed that, while the selected declustering algorithm did not significantly affect the completeness periods of moderate to large size earthquakes, it considerably altered those of small magnitude events (e.g. M
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4.3–5.2) and consequently the recurrence parameters of the source zones. Depending on the declustering algorithm and input parameters, the activity rate was observed to vary up to a factor of two. The differences in the declustered catalogues obtained from different declustering approaches resulted in considerable variations in seismic hazard estimations. The hazard maps at return periods of 475 and 2475 years indicated that peak ground acceleration values may vary up to 20% at some locations. Moreover, the differences in 5% damped elastic spectral accelerations at T = 0.2 for the return periods of 475 and 2475 years are about 18 and 12%, respectively, on the southern shores of Istanbul where the highest hazard levels are observed.
A review on the historical evolution of seismic hazard maps in Turkey is followed by summarizing the important aspects of the updated national probabilistic seismic hazard maps. Comparisons with the ...predecessor probabilistic seismic hazard maps as well as the implications on the national design codes conclude the paper.
PURPOSE: The new situation arising from the COVID-19 pandemic has brought many difficulties for companies worldwide. To combat the pandemic, governments have enforced lockdown and closure of ...businesses, and in response, companies have developed various reactive strategies to ensure their survival. The purpose of this study is twofold: to examine the impact of COVID-19 on firms and examine firm reactions towards the COVID-19 crisis. The study analyses the impact of COVID-19 on firm size, ownership type, and industry characteristics. Secondly, to analyze firm reactions based on four components: technological preferences, strategic behavior, management practices, and social networks. METHODOLOGY: This study employs a quantitative method, using a survey of 320 firm owners and managers conducted in Kosovo by the Institute of Entrepreneurship and Small Business. FINDINGS: Findings suggest that income dropped significantly for SMEs based on the firm size. Based on industry characteristics, findings show that all industries have been influenced negatively. Regarding the ownership type, findings suggest that family firms are more affected by COVID-19 than non-family firms. Factor analysis suggests that the technological preferences, managerial practices and strategic behavior, and social networks effectively responded to the crisis derived from COVID-19. Findings also suggest that firms did not employ a single reaction (e.g., technological change) but combined several reactions where one reaction led to another reaction that proved effective and led to firm survival during the crisis. IMPLICATIONS: The implications of this study are as follows: firstly, this study examines the impact of COVID-19 and, at the same time, firm reactions to the crisis; secondly, contrary to previous studies, this study shows that all industries have been influenced negatively, including all SMEs; thirdly, this study shows that ownership type was an important factor concerning the impact of COVID-19, where family firms were influenced more than non-family firms; this is due to the distinct characteristic of organizational structure that family firms have, including the involvement of members of family firms. Last, this study shows that a single reaction of firms does not lead to survival, but the chain of reactions combined with dimensions shown above. ORIGINALITY/VALUE: Despite growing theoretical and empirical literature about COVID-19 and firms, this study shows the impact and firm responses towards the crisis of COVID-19. Furthermore, focusing on the context of Kosovo, the study contributes to the challenges that firms face in different cultural and institutional settings.
Are you aware of the danger?' The 'danger' was fear of 'reactionary' insurgent Islam ('Irtica') and this was the chilling slogan in the 'Republic' newspaper in 2006 - over 80 years after the ...establishment of the secular Republic of Turkey. When Kemal Ataturk's Republic of Turkey was set up in 1923 as a secular state, sweeping political, social, cultural and religious reforms followed. Islam was no longer the official religion of the state, the Sultanate was abolished, all Turkish citzens were declared equal without reference to religion and secular control of education curbed clerical influence. In Azak's phrase, 'secularism was the central tenet of Kemalism' and the ruling philosophy of positvism overshadowed traditional religion. But the fear of resurgent and fanatical Islam continued, fuelled by the Menemen Incident - when a religious extremist murdered a state official - the attempt on the life of the proprietor of the leading liberal newspaper, the 'Fatherland', and the rise of Said Nursi's 'Nurcus' faith movement preaching a suspected fanatical Islam. And in the 21st century fear still haunts the state with the Council of State's controversial upholding of the headscarf ban and with suspected Islamist influence in modern political parties like the Justice and Development Party (JDP). Azak's revisionist and orginal study follows the struggle between religion and secularism but shows how Ataturk's secular state strove for an idealised 'Turkish Islam' - the 'social cement' of the Turkish nation - stripped of superstition and obscurantism and linked to modern science and rational, positivist, philosophy. The Young Turk ideal of 'Turkish Islam' could make Ataurk's 'catching of the train of civillisation' possible. Thus Islam would be, in Azak's view, 'personal, enlightened, rational and national'. 'Turkish Islam' has also retained its traditional form in the modern state and Ataturk's Mausoleum dominates the capital as a pantheon, attracts popular devotion, and even secularism and inspires semi-religious acclamation at Aturturk's shrine - 'Turkey is secular, it will remain secular'.
Following a 2015 ruling in the Turkish Supreme Court, vaccine resistance has increased significantly in Turkey. Where childhood vaccination was once compulsory, it is now voluntary, enabling the ...transformation of Turkish lay medical culture. This medical culture rose in political importance during the COVID-19 pandemic. Yet, little is known about vaccine hesitancy and resistance in Turkey, and the interconnections with the wider political atmosphere in the country. We draw upon fieldwork conducted during the COVID-19 pandemic and explore the rationales behind people's vaccination choices. We argue that vaccines encouraged by the state offer citizens opportunities for individuation and resistance to the more generalized coercive practices of the Turkish state.
► Infants of depressed mothers had a stable lower cognitive score over the period 6–18 months of age as compared to the infants of nondepressed mothers. ► The girls increased their cognitive scores ...as compared to the boys over the same time period. ► The results are discussed in light of stability of depression symptoms over the follow up and sex differences in cognitive development.
The effect of maternal depression on the trajectories of cognitive development was studied in 26 infants with depressed mothers as compared to a group of 24 infants with non-depressed mothers. The infants were tested on Mullen Scales of Early Learning when they were 6, 12 and 18 months old. Mothers reported their depressive symptoms over the follow ups. The study also investigated if there were sex differences in the cognitive trajectories. Multilevel modeling analyses revealed that infants of depressed mothers had a stable lower cognitive score over the period 6–18 months of age as compared to the infants of non-depressed mothers, and that the girls tended to increase their cognitive scores as compared to the boys over the same time period. The results are discussed in light of the stability of depression symptoms over the follow up and sex differences in cognitive development.
We have investigated new Pauli Fibonacci and Pauli Lucas quaternions by taking the components of these quaternions as Gaussian Fibonacci and Gaussian Lucas numbers, respectively. We have calculated ...some basic identities for these quaternions. Later, the generating functions and Binet formulas are obtained for Pauli Gaussian Fibonacci and Pauli Gaussian Lucas quaternions. Furthermore, Honsberger’s identity, Catalan’s and Cassini’s identities have been given for Pauli Gaussian Fibonacci quaternions.
The magnitude frequency distributions (MFDs) are one of the most important components of seismic source modeling in probabilistic seismic hazard analysis (PSHA). They describe the annual occurrence ...rates of ruptures that are expected to occur in the seismic source. Eventually, the occurrence rates (or probabilities) of ruptures affect the exceedance rate (or probability) and the amplitude of the target ground-motion intensity metric, which is the essential product in PSHA. To this connection, proper portrayal of parametric uncertainty in MFDs entails justifiable ground-motion amplitude exceedance distributions. In this paper, we propose two alternative approaches to account for the parametric uncertainties in the modeling of MFDs. Both approaches treat MFD model parameters as random variables and describe their conditional probability distributions conditioned on seismic source activity. Although both approaches are tailored to structure a proper MFD logic-tree, they differ in the way they handle the conditional probabilities to delineate the parametric uncertainty associated with each MFD model parameter. We first explain the theoretical background of the alternative methods, and then discuss their similarities (and differences) from a case study.
