Principal Component Analysis and Artificial Intelligence Approaches for Solar Photovoltaic Power Forecasting

In recent years, renewable energy sources have experienced remarkable growth. However, their spatial and temporal diversity makes their large-scale integration into the current power grids difficult, as the balance between the electricity output and the consumption must be maintained at all times. Therefore, it is important to focus on the resources forecast to enhance the integration of renewable energy sources, such as solar in this study. In this article, a comparative analysis of two main machine learning methods was conducted for the prediction of the hourly photovoltaic output power. Furthermore, since various factors, such as climate variables, can impact the solar photovoltaic power and complicate the prediction process, the principal component analysis was employed to investigate the interactions between the multiple predictors and minimize the dimensionality of the datasets. The prevalent factors were then used in the predictive models as inputs. This field research is very crucial because the higher the prediction accuracy, the greater the profit for energy dealers and the lower the costs for customers

Droop control in DQ coordinates for fixed frequency inverter-based AC microgrids

This paper presents a proof-of-concept for a novel dq droop control technique that applies DC droop control methods to fixed frequency inverter-based AC microgrids using the dq0 transformation. Microgrids are usually composed of distributed generation units (DGUs) that are electronically coupled to each other through power converters. An inherent property of inverter-based microgrids is that, unlike microgrids with spinning machines, the frequency of the parallel-connected DGUs is a global variable independent from the output power since the inverters can control the output waveform frequency with a high level of precision. Therefore, conventional droop control methods that distort the system frequency are not suitable for microgrids operating at a fixed frequency. It is shown that the proposed distributed droop control allows accurate sharing of the active and reactive power without altering the microgrid frequency. The simulation and hardware-in-the-loop (HIL) results are presented to demonstrate the efficacy of the proposed droop control. Indeed, following a load change, the dq droop controller was able to share both active and reactive power between the DGUs, whereas maintaining the microgrid frequency deviation at 0% and the bus voltage deviations below 6% of their respective nominal values

Erdheim-Chester disease: a rare histiocytosis (case report and review of the literature)

We report a case of Erdheim-chester disease, a rare non-langerhans histiocytosis revealed by polydipsia-polyuria syndrome in a 26 years old woman, trated by interferon with a good response

Le syndrome du canal carpien chez les patients hémodialysés chroniques

Le syndrome du canal carpien (SCC) regroupe l'ensemble des signes et symptômes liés à la compression du nerf médian dans le canal carpien. Cette manifestation de l'amylose à béta2-microglobuline est une complication fréquente de l'hémodialyse au long cours. L'objectif de ce travail est d'analyser les caractéristiques du SCC et de déterminer les facteurs liés à sa survenue chez les hémodialysés chroniques.Nous rapportons une étude transversale monocentrique, menée au 3ème trimestre de l'année 2009, portant sur les patients adultes hémodialysés chroniques au service de Néphrologie-Hémodialyse au CHU de Fès. 59 patients ont accepté de participer à l'étude. Leurs âge moyen est de 48 ± 15 ans avec un sex-ratio de 0,9. Ils bénéficient tous de l'hémodialyse intermittente à raison de 10 à 12 heures par semaine, par une membrane de dialyse en polysulfone à basse perméabilité. La durée moyenne en hémodialyse est de 83 ± 6,5 mois. La prévalence du SCC dans notre centre est de 30,5%. L'électromyogramme (EMG) a confirmé la suspicion clinique du SCC chez 11 patients et a diagnostiqué un SCC chez 8 patients asymptomatiques. La comparaison statistique entre les deux groupes de patients avec et sans SCC a démontré que la survenue de ce syndrome est liée à: l'âge actuel, l'âge avancé à la mise en hémodialyse, le sexe féminin, l'excès pondéral, et l'abord vasculaire. Le SCC est une complication fréquente de l'hémodialyse chronique. L'amélioration de la qualité de dialyse permettrait de réduire le risque de survenue du SCC.Pan African Medical Journal 2013; 14:1

Complications neurologiques de la carence en thiamine (Vitamine B1) : A propos d’un cas avec revue de la litterature

Introduction: La carence en thiamine peut se manifester par deux formes cliniques : une forme cardiaque nommée béribéri humide, et une forme neurologique qui est le béribéri sec ; cette dernière peut se traduire cliniquement par une neuropathie périphérique, ou par une encéphalopathie de Gayet-Wernicke, caractérisée par la triade classique : ophtalmoplégie, ataxie et état confusionnel. Cette encéphalopathie est souvent difficile à identifier et son diagnostic est retardé. Observation: Nous rapportons le cas d’une patiente de 27 ans, suivie pour leucémie aigue promyélocytaire réfractaire, avec atteinte du système nerveux central, ayant eu une alimentation parentérale prolongée, en raison des vomissements incoercibles et persistants, suite à laquelle elle a développé une encéphalopathie de Wernicke, ayant bien évolué sous supplémentation vitaminique intra-veineuse. Commentaires:Nous aborderons dans ce travail, l’intérêt du diagnostic précoce, les différents contextes évocateurs et les aspects clinique, radiologique ainsi que les options thérapeutiques dans l’encéphalopathie de Wernicke.   English title: Neurological Complications Of Thiamine Deficiency, A Case Report With Literature Review Background: Thiamine deficiency can manifest itself in two clinical forms: a cardiac form called wet beriberi, and a neurological form which is dry beriberi; the latter can result clinically by peripheral neuropathy, or by Gayet-Wernicke encephalopathy, characterized by the classic triad: ophthalmoplegia, ataxia and confusional state. This encephalopathy is often difficult to identify and its diagnosis is delayed. Observation: We report the case of a 27-year-old patient, followed for refractory acute promyelocytic leukemia, with central nervous system damage, having had a prolonged parenteral diet, due to incoercible and persistent vomiting, following which she developed an encephalopathy of Wernicke, having evolved well under intravenous vitamin supplementation. Comments: In this work, we will discuss the interest of early diagnosis, the different suggestive contexts and the clinical, radiological aspects as well as the therapeutic options in Wernicke's encephalopathy

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century