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This article provides a fresh insight into the dynamic nexus between oil prices, the Saudi/US dollar exchange rate, inflation, and output growth rate in Saudi Arabia' economy, using novel Morlet' wavelet methods. Specifically, it implements various tools of methodology: the continuous wavelet power spectrum, the cross-wavelet power spectrum, the wavelet coherency, the multiple and the partial wavelet coherence to the annual sample period 1969-2014. Our results unveil that the relationships among the variables evolve through time and frequency. From the time-domain view, we show strong but non-homogenous linkages between the four variables. From the frequency-domain view, we uncover significant wavelet coherences and strong lead-lag relationships. From an economic view, the wavelet analysis shows that Saudi economy is still exposed to several global risk factors, which are mainly related to the oil market volatility, and the pegging of the local currency to the US dollar. Such risk factors strongly and negatively affect the real economic growth, exert more pressure on inflation, and substantially limit the freedom to pursue an independent monetary policy.

This paper examines the combined and separate effects of geopolitical risk, economic policy uncertainty, and oil prices on the stock market within a multivariate time-frequency framework, focusing on Saudi Arabia as an oil-rich country. We implement the wavelet local multiple correlation approach using monthly data from January 2000 to December 2024. Our results reveal that oil prices, geopolitical risk, and economic uncertainty are key drivers of Saudi market behavior. The joint and individual effects vary significantly across time scales and frequencies. Increasing uncertainty surrounding economic policies and rising geopolitical tensions in the region have intensified the impact of oil price movements on the Saudi market. These findings have several implications for portfolio managers, foreign investors, and policymakers. When analyzing and forecasting stock returns, portfolio managers should consider oil prices, geopolitical risk, and changes in economic policy uncertainty.

In this study, we investigate the connectedness between sharia stock index and three Islamic bond yields within a global perspective of the Gulf Cooperation Council Islamic financial markets. The main novelty of the present study is that we extend previous studies by performing three wavelet variants in bivariate and multivariate frameworks, namely the wavelet multiple correlation, the wavelet multiple cross correlation and wavelet cohesion. The findings point out a significant changing pattern in the dynamic linkage between sharia stocks and Islamic bond yields in the time-frequency domain. A strong positive association is evidenced in the short horizons and a negative linkage is branded for longer time-scales. Some resemblances are found for the wavelet cohesion corroborating the existence of potential portfolios’ diversification opportunities at lower frequencies. The multivariate wavelet cross correlation unveils that the intensity of the co-movement reaches its zenith at high frequencies. These results are not similar to the bivariate wavelet coherence but are coincident with the wavelet cohesion approach, which may be due to the difference in dimensionality of the wavelet approaches. The implications of this study will be useful for Islamic portfolio managers, international investors and market regulators in better encircling the best ways to adopt a proactive knowledge of Islamic financial markets behavior.

Enhancing future economic growth through higher economic complexity is vital for sustainable growth strategies. Even though most studies are concerned with the key factors governing the economic complexity process, there needs to be more studies about the impact of risk factors on economic sophistication evolvement, particularly for oil-rentier economies. The present paper intends to delve into the dynamic connectedness between some risk factors, such as economic, political, and geopolitical risks and oil price volatility and the progress of economic complexity. We utilized quarterly data (1995Q1-2021Q4) for Saudi Arabia as a heavy oil-rich economy. As the first study to delve into the short-long term connections at various time scales and frequencies within a multivariable setting, we contribute to the literature by offering a spotless picture of economic complexity risk factors. In doing so, we resort to a novel wavelet local multiple correlation method, which can explore the varying patterns of time periods in the interconnections between the variables. Our findings disclose that oil volatility, geopolitical risk, and global uncertainties are positively connected to economic complexity over the long run. In contrast, their short-term effect is weak and mostly insignificant. These results indicate the resiliency of the Saudi economy to external to oil volatility shocks and intensification of global and local uncertainties. These outcomes offer policymakers new insights and prominent policy recommendations when designing economic strategies to achieve higher economic sophistication and sustainable growth.

In oil-dependent countries, the energy transition process is ongoing and it appeals substantial and necessary adjustments in terms of diversification. We attempt to provide a systematic analysis of the connectedness between energy transition, oil revenue and economic diversification using novel econometric approach, wavelet decomposition and panel data estimation. Our attention will be focused on the dynamics and causal relationships between energy transition process and economic diversification by checking the role of oil revenue. We use second generation unit roots, and a particular attention is given to cross-sectional dependence of the series. Results show that correlations between wavelet components are absent in the short term, weak in the medium term, and moderate in the long-run. Causality tests support a bidirectional causality between economic diversification and energy transition and between economic diversification and net oil revenue, in the medium and long-run scale levels. Our results would have several prominent implications for policy makers, in oil-dependent countries, when designing energy transitions and economic diversifications strategies, and gives and insightful look about the future of these countries. 

BackgroundThe molecular anomalies causing moyamoya disease (MMD) and moyamoya syndromes (MMS) are unknown in most patients.ObjectiveThis study aimed to identify de novo candidate copy number variants (CNVs) in patients with moyamoya.MethodsRare de novo CNVs screening was performed in 13 moyamoya angiopathy trios using whole exome sequencing (WES) reads depth data and whole genome high density SNP array data. WES and SNP array data from an additional cohort of 115 unrelated moyamoya probands were used to search for recurrence of these rare de novo CNVs.ResultsTwo de novo CNVs were identified in two unrelated probands by both methods and confirmed by qPCR. One of these CNVs, located on Xq28, was detected in two additional families. This interstitial Xq28 CNV gain is absent from curated gold standard database of control genomic variants and gnomAD databases. The critical region contains five genes, including MAMLD1, a major NOTCH coactivator. Typical MMD was observed in the two families with a duplication, whereas in the triplicated patients of the third family, a novel MMS associating moyamoya and various systemic venous anomalies was evidenced.ConclusionThe recurrence of this novel Xq28 CNV, its de novo occurrence in one patient and its familial segregation with the affected phenotype in two additional families strongly suggest that it is pathogenic. In addition to genetic counselling application, its association with pulmonary hypertension is of major importance for clinical care. These data also provide new insights into the genomic architecture of this emblematic, non-atherosclerotic, large vessel disease.

Platelets transfusion is a safe process, but during or after the process, the recipient may experience an adverse reaction and occasionally a serious adverse reaction (SAR). In this review, we focus on the inflammatory potential of platelet components (PCs) and their involvement in SARs. Recent evidence has highlighted a central role for platelets in the host inflammatory and immune responses. Blood platelets are involved in inflammation and various other aspects of innate immunity through the release of a plethora of immunomodulatory cytokines, chemokines, and associated molecules, collectively termed biological response modifiers that behave like ligands for endothelial and leukocyte receptors and for platelets themselves. The involvement of PCs in SARs-particularly on a critically ill patient's context-could be related, at least in part, to the inflammatory functions of platelets, acquired during storage lesions. Moreover, we focus on causal link between platelet activation and immune-mediated disorders (transfusion-associated immunomodulation, platelets, polyanions, and bacterial defense and alloimmunization). This is linked to the platelets' propensity to be activated even in the absence of deliberate stimuli and to the occurrence of time-dependent storage lesions.

Background Moyamoya angiopathy (MMA) is a rare cerebrovascular condition leading to stroke. Mutations in 15 genes have been identified in Mendelian forms of MMA, but they explain only a very small proportion of cases. Our aim was to investigate the genetic basis of MMA in consanguineous patients having unaffected parents in order to identify genes involved in autosomal recessive MMA. Methods Exome sequencing (ES) was performed in 6 consecutive consanguineous probands having MMA of unknown etiology. Functional consequences of variants were assessed using western blot and protein 3D structure analyses. Results Causative homozygous variants of NOS3 , the gene encoding the endothelial nitric oxide synthase (eNOS), and GUCY1A3 , the gene encoding the alpha1 subunit of the soluble guanylate cyclase (sGC) which is the major nitric oxide (NO) receptor in the vascular wall, were identified in 3 of the 6 probands. One NOS3 variant (c.1502 + 1G > C) involves a splice donor site causing a premature termination codon and leads to a total lack of eNOS in endothelial progenitor cells of the affected proband. The other NOS3 variant (c.1942 T > C) is a missense variant located into the flavodoxine reductase domain; it is predicted to be destabilizing and shown to be associated with a reduction of eNOS expression. The GUCY1A3 missense variant (c.1778G > A), located in the catalytic domain of the sGC, is predicted to disrupt the tridimensional structure of this domain and to lead to a loss of function of the enzyme. Both NOS3 mutated probands suffered from an infant-onset and severe MMA associated with posterior cerebral artery steno-occlusive lesions. The GUCY1A3 mutated proband presented an adult-onset MMA associated with an early-onset arterial hypertension and a stenosis of the superior mesenteric artery. None of the 3 probands had achalasia. Conclusions We show for the first time that biallelic loss of function variants in NOS3 is responsible for MMA and that mutations in NOS3 and GUCY1A3 are causing fifty per cent of MMA in consanguineous patients. These data pinpoint the essential role of the NO pathway in MMA pathophysiology.

Purpose The purpose of this paper is to expand understanding of the determinants of performance in newly privatized firms by empirically examining the interaction effect of internal corporate governance and Big Four auditors in Middle Eastern and North African countries. Specifically, the paper contributes to the existing literature by identifying whether there is a substitute or complementary relation between internal corporate governance mechanisms and Big Four auditors. Design/methodology/approach A data set of 88 NPFs of MENA countries over the period 1987-2010 is used. The methodology is based on two-stage least squares regression analysis. Findings Results show that government ownership and the proportion of outside directors can substitute for Big Four auditors. However, foreign ownership and the CEO duality reinforce each other to improve performance of NPFs. Overall, these findings suggest that in the presence of agency problems within privatization process, different combinations of internal corporate governance and Big Four auditors can serve as a monitoring response in NPFs and should yield a superior performance. Practical implications This study gives insights to policy makers’ managers and regulators who are interested in investing in MENA region. The authors argue that information regarding who is auditing the firm is very value relevant for investors investing in the MENA region. Firms with Big Four auditor as external auditors are likely to disclose better information than those that are audited by non-Big Four auditors. Originality/value This paper extends the understanding of the determinants of the post-privatization performance in MENA region. It fills the privatization literature void by introducing Big Four auditors as an external governance mechanism. To the authors’ knowledge, the authors’ work is the first study that investigates whether Big Four auditors play an important role and interact with internal corporate governance mechanisms to address the dominant/minority shareholders post-privatization agency problems.

In this paper, we use the copulas functions in financial application, namely to examine the assumption of asymmetric dependence and to calculate some measures of risk. The first step consists of deducing filtered residuals for each return series by an asymmetric Glosten-Jagannathan-Runkle Generalized Autoregressive conditional Hetero skedasticity (GJR-GARCH) model. For the second step, we use an estimation of a Generalized Pareto Distribution for the upper and lower tails to determine the empirical semiparametric marginal Cumulative Distribution Function. In our approach, we propose to use a portfolio consisting of increments from five countries. The GJR-GARCH copula is then applied to the data and used to reduce correlation between the simulated residuals of each series. The marginal distributions of filtered residuals are fitted with a semi-parametric Cumulative Distribution Function using the copulas' functions and Generalized Pareto Distribution for tails. For each series, we compute Value-at-Risk and Conditional Value-at-Risk.