1,720,965 research outputs found
Long Memory in the Turkish Stock Market Return and Volatility
Full text linkThis paper examines the dual long memory property of the Turkish stock market. The data set consists of daily returns, and long memory tests are carried out both for the returns and volatility. The results indicate that long memory dynamics in the returns and volatility might be modeled by using the ARFIMA-FIGARCH model. The results of the ARFIMAFIGARCH model show strong evidence of long memory in both returns and volatility. The long memory in returns implies that stock prices follow a predictable behavior, which is inconsistent with the efficient market hypothesis. The evidence of long memory in volatility, however, shows that uncertainty or risk is an important determinant of the behavior of daily stock data in the Turkish stock market.ARFIMA, FIGARCH, Long memory, Turkish stock market
Polytomic Spillover Dynamics between Oil and Euro Markets: A High-Frequency Perspective
Full text linkThis study investigates the short-term relationship between daily West Texas Intermediate (WTI) oil prices and the Euro exchange rate (EUR) during the 2020–2024 period, which was marked by the COVID-19 pandemic and economic fluctuations. A comprehensive wavelet-based framework, including powerful tests such as phase difference, gain, coherence, correlation, and causality measures based on continuous wavelet transform, was employed. The findings reveal a significant spillover mechanism operating between commodity and foreign exchange markets during periods of economic instability. As uncertainty intensifies with market turmoil, spillover effects become more pronounced, highlighting the importance of using market dynamics and volatility information effectively in hedging strategies. The study demonstrates that multidimensional (politomic) analyses provide more realistic findings than binary (dichotomic) approaches. These results emphasize the critical importance for policymakers to monitor intermarket connections during systemic shocks. By providing a detailed analysis of high-frequency market interactions, this study contributes to the literature and offers practical implications for investors, portfolio managers, and policymakers involved in short-term trading and risk management in increasingly interconnected financial markets, particularly in Europe, a major net oil importer
Dual long memory property in returns and volatility: The evidence from Turkish stock market
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Sürekli Dalgacık Dönüşümlü Granger Nedensellik Analizi ile Bist-30 Endeksi ve Endeks Vadeli İşlem Sözleşmesi Üzerine Bir Araştırma
Full text linkFinansal veriler iç içe geçmiş salınımlar, ani değişimler ve görece olarak daha yavaş değişen trend bileşenlerini içeren karmaşık bir yapıya sahiptir. Dalgacık analizi ile söz konusu bileşenler ayrıştırılarak verinin sahip olduğu bileşenlerdeki değişmeleri içeren zaman-frekans grafikleri oluşturulmaktadır. Böylelikle verideki dinamiklerin ortaya çıkarılması amacıyla salınımların zamana, döneme ve salınım şiddetine göre değişiminin analizi mümkün olmaktadır. Bu kapsamda çalışmada, BIST-30 endeksi ve endeks vadeli işlem sözleşmeleri arasındaki nedensellik ilişkisi zaman boyutu dikkate alınarak incelenmiştir. BIST 30 endeksi Türkiye sermaye piyasaları için temel endeks niteliğindedir. Bu kapsamda endeks, imalat sanayi, bankacılık ve mali kurumlar, perakende gibi birçok sektörde faaliyet gösteren firmaları kapsamakta, Türkiye sermaye piyasaları için önemli bir gösterge niteliği arz etmektedir. Spot fiyatların, vadeli işlem fiyatları üzerindeki belirleyici etkisi bu endeks aracılığı ile görülmektedir. Bu çalışmada, BIST-30 Endeks ve endeks vadeli sözleşme fiyatları arasındaki nedensellik ilişkisinin belirlenmesi amacıyla 02.07.2012 – 30.11.2018 dönemindeki, 1613 adet günlük veri için sürekli dalgacık dönüşümünü temel alan parametrik olmayan Granger nedensellik testi yapılmıştır. Çalışmada MATLAB yazılımından yararlanılmıştır. Çalışmada kullanılan veri setleri www.investing.com adresinden temin edilmiştir. Çalışma sonucunda incelenen 16 günlük, 16-128 gün dönemlik, 16-32 gün dönemlik dalgalanmalarda ve 256 gün ve daha uzun dönemlik dalgalanmalarda nedenselliğin yönü ve şiddetinin gerek ekonomik gerek politik ve gerekse finansal nedenlerle farklılaştığı, dönemler düzeyinde incelenen nedensellik ilişkisinin küresel düzeyde piyasalar arasında da ortaya çıktığı sonucuna ulaşılmıştır. Dolayısıyla finansal piyasaların oynaklığının zamana bağlı olarak değişim gösterdiği, yatırımcıların spot pozisyonlarını alırken vadeli işlem fiyatlarını belirledikleri, gelecek dönemlere ilişki yapılacak yatırımlarda spot ve vadeli fiyatlar arasındaki ilişkilerin gözönünde bulundurulması gerektiği çalışmanın ilgi çekici sonuçları arasındadır
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