Operating photovoltaic (PV) systems under partial shading conditions results in significant power losses. To mitigate partial shading effects, distributed maximum power point tracking (DMPPT) ...architectures have been proposed. An emerging DMPPT technique represented by PV module cascaded converters (MCCs) has been widely reported in the literature. In this architecture, a DC converter is allocated for each PV module to process and maximise its power. In this sense, mismatch effects are mitigated between PV modules. While MCC architecture has prominent advantages and value-added features, its challenges and limitations cannot be ignored. This study presents a comprehensive review of the state of the art of PV MCC architecture to help readers realise the progress of this DMPPT technique. Several points are extensively discussed and analysed including concept realisation and analysis, DC converter topologies and design optimisation, DMPPT performance limitations, DMPPT control, and protection. The main concepts are reemphasised through a set of simulations. Finally, a list of potential research areas in this field is introduced.
Partial shading is a serious problem limiting the efficiency of photovoltaic (PV) systems. Differential power processing (DPP) architectures have been proposed to mitigate mismatch power losses ...caused by partial shading. However, maximum power point tracking (MPPT) for DPP converters is still an area of research. Instead of employing heuristic techniques, the proposed method is deterministic that can uniquely determine the respective maximum power points (MPPs) for the DPP Converters relying on the PV mathematical model and provided incident irradiances. The irradiances of the submodules are estimated using captured images obtained by an optical camera. Unlike the existing methods in literature which either produce fast transient response or accurate steady state tracking, the proposed method provides both fast transient response and accurate steady state output without oscillations. Moreover, the proposed approach does not need communication between converters or current sensing for the MPPT. The effectiveness of the proposed method is validated both by Simulink simulations and experimentally.
Although financial inclusion (FI) has attracted growing attention from academics and policy makers, the effect of digital finance (DF) on FI has not been studied sufficiently. Therefore, this study ...examines the association between DF and FI in the Middle East and North Africa (MENA) region. FI is measured with a composite index incorporating three subindexes: access, availability, and usage of financial services; DF is measured by the number of ATMs per 100,000 adults. A system–generalized method of moments (sys-GMM) panel method is employed with annual data on 12 countries in the MENA region over the period 2004–2020. Additionally, five control variables are used in the study. The results confirm the role of DF in enhancing FI in the MENA countries. Policy makers and digital financial service providers in MENA countries can use the study's findings to expand the boundaries of FI in their countries.
While research on the hydrologic impact of different types of stormwater control measures (SCMs) is extensive, little research exists linking urbanization, widespread implementation of SCMs and ...channel stability in headwater streams. This study evaluated whether the unified stormwater sizing criteria (USSC) regulations in the state of Maryland, USA, which require the use of both end‐of‐pipe and distributed, small‐scale SCMs, protect channel stability. To achieve this goal, a coupled hierarchical modelling approach utilizing the Storm Water Management Model (SWMM) and the Hydrologic Engineering Center River Analysis System 6.3 (HEC‐RAS) was developed to predict changes in streamflow and sediment transport dynamics in a first‐order gravel‐bed, riffle‐pool channel. Storm event discretization revealed that 88% of observed storm events during the 16 years (2004–2020) had durations less than 18 h and that the greatest peak flows resulted from storm events with durations less than 24 h. HEC‐RAS simulation results also showed that both channel degradation and aggradation, as high as 1.2 m, will likely occur due to regulations which require the use of 24 h duration design storms with a target stormwater detention time rather than bed material sediment transport limits. Overall, this study provides valuable insights into the complex interactions between SCM practises, flow regimes and sediment transport dynamics in heavily urbanized watersheds. It is recommended that SCMs be designed using a continuous simulation model with at least 10 years of continuous rainfall data. Furthermore, to protect channel stability, the SCM design goal should focus on maintaining pre‐development sediment transport regimes across a range of flows.
Urban stormwater regulations which require distributed stormwater controls to protect water quality and detention of a volume of runoff from frequent storm events do not protect receiving streams from long‐term channel degradation.
Seminal plasma contains a variety of extracellular vesicles (EVs) that deliver RNAs including microRNAs (miRNAs) molecules. However, the roles of these EVs along with their delivered RNAs and their ...interactions with male infertility are not clear. Sperm-associated antigen 7 (SPAG 7) is expressed in male germ cells and plays a crucial role in several biological functions associated with sperm production and maturation. In this study, we aimed to identify the post-transcriptional regulation of SPAG7 in seminal plasma (SF-Native) and seminal plasma-derived extracellular vesicles (SF-EVs) collected from 87 men undergoing infertility treatment. Among the multiple binding sites for miRNAs within its 3'UTR of SPAG7, we identified the binding of four miRNAs (miR-15b-5p, miR-195-5p, miR-424-5p, and miR-497-5p) to the 3'UTR of SPAG7 by the dual luciferase assays. Analyzing sperm, we found reduced mRNA expression levels of SPAG7 in SF-EVs and SF-Native samples from oligoasthenozoospermic men. By contrast, two miRNAs (miR-424-5p and miR-497-5p) form the SF-Native samples, and four miRNAs (miR-195-5p, miR-424-5p, miR-497-5p, and miR-6838-5p) from the SF-EVs samples showed significantly higher expression levels in oligoasthenozoospermic men. The expression levels of miRNAs and SPAG7 were significantly correlated with basic semen parameters. These findings contribute significantly to our understanding of regulatory pathways in male fertility by showing a direct link between upregulated miRNA, notably miR-424, and downregulated SPAG7 both in seminal plasma and in plasma-derived EVs likely contributing to oligoasthenozoospermia.
Predicting the output power of partially‐shaded photovoltaic (PV) systems has a crucial role in the field of photovoltaic system studies and design. A significant number of models, circuit simulation ...techniques and power prediction formulations are proposed in the literature. However, several factors could limit their application such as computational burden, accuracy and their applicability to different levels of photovoltaic system. An analytical circuit‐based approach is proposed to predict the output power and power losses of partially‐shaded photovoltaic systems. The proposed approach is distinguished by high accuracy, low computational time and applicability to all photovoltaic system levels. Hence, it enables the assessment of partial shading mitigation ability of various photovoltaic system architectures. Furthermore, the proposed approach has no limitations on the size of photovoltaic system, for example, as in circuit‐based simulation analysis. An extensive simulation‐based comparison study for five partially‐shaded photovoltaic systems is conducted to compare the accuracy and computational time of the proposed approach with the detailed, well‐established single diode model. The accuracy of the proposed approach is also validated experimentally on a photovoltaic system of 12 series‐connected photovoltaic modules. Furthermore, a set of comparisons with experimental measurements from the literature is presented.
•In this research, state-of-the-art approaches based on supervised machine learning are presented to tackle aspect-based sentiment analysis (ABSA) challenges of Arabic Hotels’ reviews.•Two approaches ...of deep recurrent neural network (RNN) and support vector machine (SVM) are implemented and trained along with lexical, word, syntactic, morphological, and semantic features.•The proposed approaches are evaluated using a reference dataset of Arabic Hotels’ reviews annotated using an ABSA framework presented in the Semantic Evaluation workshop 2016 (SemEval-ABSA16).•Evaluation results show that the SVM approach outperforms the other deep RNN approach in the research investigated tasks (T1: aspect category identification (E#A allocation), T2: aspect opinion target expression (OTE) extraction, and T3: aspect sentiment polarity identification).•Whereas, when focusing on the execution time required for training and testing the models, the deep RNN was faster especially for the second task.
In this research, state-of-the-art approaches based on supervised machine learning are presented to address the challenges of aspect-based sentiment analysis (ABSA) of Arabic Hotels’ reviews. Two approaches of deep recurrent neural network (RNN) and support vector machine (SVM) are implemented and trained along with lexical, word, syntactic, morphological, and semantic features. The proposed approaches are evaluated using a reference dataset of Arabic Hotels’ reviews. Evaluation results show that the SVM approach outperforms the other deep RNN approach in the research investigated tasks (T1: aspect category identification, T2: aspect opinion target expression (OTE) extraction, and T3: aspect sentiment polarity identification). Whereas, when focusing on the execution time required for training and testing the models, the deep RNN execution time was faster, especially for the second task.
The expression levels of various genes involved in human spermatogenesis are influenced by microRNAs (miRNAs), specifically microRNA-23a/b-3p. While certain genes are essential for spermatogenesis ...and male germ cell function, the regulation of their expression remains unclear. This study aimed to investigate whether microRNA-23a/b-3p targets genes involved in spermatogenesis and the impact of this targeting on the expression levels of these genes in males with impaired fertility. In-silico prediction and dual-luciferase assays were used to determine the potential connections between microRNA-23a/b-3p overexpression and reduced expression levels of 16 target genes. Reverse transcription-quantitative PCR (RT-qPCR) was conducted on 41 oligoasthenozoospermic men receiving infertility treatment and 41 age-matched normozoospermic individuals to verify the lower expression level of target genes. By employing dual-luciferase assays, microRNA-23a-3p was found to directly target eight genes, namely
, and
, while microRNA-23b-3p directly targeted three genes, namely SOX6,
, and
. The intentional alteration of the microRNA-23a/b binding site within the 3' untranslated regions (3'UTRs) of the eight genes resulted in the loss of responsiveness to microRNA-23a/b-3p. This confirmed that
, and
are direct targets for microRNA-23a-3p, while
, and
are direct targets for microRNA-23b-3p. The sperm samples of oligoasthenozoospermic men had lower expression levels of target genes than age-matched normozoospermic men. Correlation analysis indicated a positive correlation between basic semen parameters and lower expression levels of target genes. The study suggests that microRNA-23a/b-3p plays a significant role in spermatogenesis by controlling the expression of target genes linked to males with impaired fertility and has an impact on basic semen parameters.
This study explores the challenges facing the current e-payment systems and investigates the main factors that support using the e-payment system. This study used a cross-sectional approach. An ...online survey was conducted on Yemeni consumers as part of the collection of data. The data from 486 questionnaires were analyzed using smartPLS4 and Jamovi software for structural model analysis and statistical analysis. According to the PLS-SEM results, the structural model shows that R2 is 0.757, which explains the variances in behavioral intention via all the constructs. Statistically, the intention to use e-payment systems is significantly and positively influenced by performance and effort expectancies and social influence. In contrast, facilitation conditions are significantly and negatively correlated with behavioral intention. This is attributed to consumers’ view of the infrastructure of Internet services, which does not contribute to the behavioral intention and acceptance of using electronic payment in Yemen. Contrary to expectations, age does not moderate the relationship between performance expectancy, social influence, and intention to use e-payment systems; hence, the related hypothesis was not supported. This study provides valuable suggestions for policymakers, designers, developers, and researchers, enabling them to better understand the critical aspects of using the electronic payment system. This study developed a model for predicting the likelihood of acceptance of electronic payments in a country that has not given adequate attention to this issue. An application and evaluation of the UTAUT model in Yemen are presented in this study.
Sperm mitochondrial dysfunction causes the generation of an insufficient amount of energy needed for sperm motility. This will affect sperm fertilization capacity, and thus, most asthenozoospermic ...men usually require assisted reproductive techniques. The etiology of asthenozoospermia remains largely unknown. The current study aimed to investigate the effect of mitochondrial genetic variants on sperm motility and intracytoplasmic sperm injection (ICSI) outcomes. A total of 150 couples from the ICSI cycle were enrolled in this study. One hundred five of the male partners were asthenozoospermic patients, and they were subdivided into three groups according to their percentage of sperm motility, while forty-five of the male partners were normozoospermic. Genetic variants were screened using direct Sanger’s sequencing in four mitochondrial genes (nicotinamide adenine dinucleotide hydrogen (NADH) dehydrogenase 1 (ND1), NADH dehydrogenase 2 (ND2), NADH dehydrogenase 5 (ND5), and NADH dehydrogenase 6 (ND6)). We identified three significant variants: 13708G>A (rs28359178) in
ND5
, 4216T>C (rs1599988) in
ND1
, and a novel 12506T>A in
ND5
with
P
values 0.006, 0.036, and 0.013, respectively. The medians of sperm motility, fertilization rate, embryo cleavage score, and embryo quality score were significantly different between men showing 4216T>C, 12506T>A, 13708G>A and wild type, Mann-Whitney
P
values for the differences in the medians were < 0.05 in all of them. The results from this study suggest that 13708G>A, 12506T>A, and 4216 T>C variants in sperm mitochondrial DNA negatively affect sperm motility and ICSI outcomes.
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