Changes of Insulation Properties of Photovoltaic Cables Caused by Ageing Treatment

An important part of the photovoltaic power plants are cable systems. The dielectric properties of cables, reliability and durability depend on quality of production processes, operating conditions and degradation factors, as well. Expected lifetime of cable systems is more than 20-30 years in general. Their failure free operation and long-term stability of properties has a direct impact on the economic return of the investments. According to our experiences the tests in compliance with valid standards are not adequate to verify real life time during operation. Photovoltaic cables intended for use in outdoor applications for the connection between the solar panels and possible connection between panels and inverter were chosen for our experiments. The changes of insulation resistance and breakdown voltage caused by some degradation factors, mainly water, are presented. This research was inspired by real failure in operation

ASSESMENT OF DAMAGE OF SOLAR HETEROJUNCTION a-SiC/c-Si INDUCED BY NEUTRON RADIATION

Amorphous silicon carbide is known as a material resistant except others influences also against radiation. This study investigates the effects of neutron radiation on electric characteristics (I-V characteristic, impedance spectra and obtained dynamic parameters of AC equivalent circuit) of solar cell a-SiC/c-Si heterojunction structure. The heterojunction structure was irradiated using neutrons with neutron fluence 1013 cm-2. Existence of neutron induced structural defects, which could be introduced within semiconductor structure of heterojunction, has been illustrated using DC and AC analysis. The structural defects induced by neutron particles radiation affect mainly trapping mechanism. The process results in the changes of electronic elements included into proposed equivalent circuit

Influence du tabagisme et du degré de dépendance nicotinique sur la capacité de réaction chez les footballeurs: The effects of smoking and the degree of nicotinic dependence on reaction time in football players

Context and objective. Data on the reaction capacity of the footballer in sub-Saharan Africa are scarce. This study aimed to evaluate the effects of smoking on athletes’ performance in the tasks of simple reaction time and choice. Methods. We conducted a prospective cohort study enrolling thirty footballer’s smokers and 28 non-smokers. All participants were asked to perform a cycloergometric test for 3 hours, five times a week. Degree of nicotinic dependence of smokers was evaluated by Fageström test. Before, and after this effort, the subjects undertook simple reaction time tasks and reaction time of choice. The performances were measured. Results. Compared to no smokers, smokers had significantly higher simple reaction time values: at rest, 280.9 ± 30.5 ms against 213.4±10.7 ms (p < 0.0001) and at recovery, 327.3±16.6 ms against 248.0±9.3 ms ms (p < 0.0001); in the reaction time of choice, the idle values were 475.5 ± 10.8 ms against 327.1 ± 8.3 ms ms (p < 0.0001) and at the recovery, 1.1±13.3 ms versus 290.7±7.6 ms ms (p <0.0001). Tobacco-dependent smokers had a higher reaction time compared to control subjects.  Conclusion. Footballer’s smokers exhibit higher simple reaction time values than non-smokers. Active smoking is absolutely incompatible with high-level sports. Contexte et objectif. Les données relatives à la capacité de réaction chez le footballeur en Afrique subsaharienne sont rares. La présente étude a évalué les effets du tabagisme sur les performances des sportifs dans les tâches de temps de réaction simple et de choix. Méthodes. Nous avons entrepris une étude de cohorte prospective enrôlant trente footballeurs fumeurs et 28 non-fumeurs. Tous les participants étaient invités à effectuer une épreuve cycloergométrique pendant 3 heures, cinq fois par semaine. Le niveau de dépendance nicotinique des fumeurs a été déterminé par le test de Fageström. Avant, au terme et au décours de cet effort, les sujets ont réalisé des tâches de temps de réaction simple et de temps de réaction de choix. Les performances ont été mesurées. Résultats. Comparés aux non-fumeurs, les fumeurs avaient des valeurs de temps de réaction simple significativement plus élevées: au repos, 280,9±30,5 ms contre 213,4±10,7 ms (p < 0,0001) et à la récupération, 327,3±16,6 ms contre 248,0±9,3 ms (p < 0,0001); au niveau du temps de réaction de choix, les valeurs au repos étaient de 475,5±10,8 ms contre 327,1±8,3 ms (p < 0,0001) et à la récupération, 441,1±13,3 ms contre 290,7±7,6 ms (p < 0,0001). Les fumeurs à grande dépendance tabagique présentaient un temps de réaction plus élevé par rapport aux sujets à faible dépendance. Conclusion. Le tabagisme actif est absolument incompatible avec la pratique sportive au haut niveau

Effet du confinement de la pandémie à COVID-19 sur les besoins nutritionnels dans une population adulte active et chez des personnes en âge de retraite à Brazzaville, République du Congo: Impact of COVID-19 lockdown on nutritional status of active adults and retirement-age population in Brazzaville, Republic of Congo

Contexte & objectif. La dimension nutritionnelle du confinement instauré à l’occasion de la pandémie COVID-19 n’a pas encore était étudiée en milieu africain. La présente étude a pour objectifs d’identifier et analyser les caractéristiques nutritionnelles chez l’adulte actif et la personne âgée congolais pour dépister d’éventuelles carences. Méthodes. Dans une enquête transversale menée lors du second confinement entre avril et mai 2020, quelques ménages de Bacongo (Brazzaville, Congo) recrutés aléatoirement, ont été interviewés sur base d’un questionnaire de type alimentaire quantitatif. Elle portait sur la nature et la quantité des aliments consommés durant toute la journée, du lever au coucher. Les apports quotidiens ont été calculés, et rendus en termes de % d’énergie fournie respectivement par les glucides, les lipides et les protides ; ainsi que les oligo-éléments, et les vitamines (A, B et C). Résultats. La valeur nutritionnelle moyenne globale était de 2123,5 ± 494,5 Kcal, chez les 183 sujets inclus (107 adultes en activité professionnelle âgés entre 31 et 59 and et 76 personnes âgées de 66 à 80 ans). Spécifiquement, les besoins en glucides étaient couverts à hauteur de 81,5 %, tandis que ceux en protéines et en lipides étaient insuffisants, respectivement de l’ordre 33,5 g/j et 59,5 g/j en moyenne. Les apports en calcium, phosphore, et magnésium, étaient conformes aux normes recommandées, étant  respectivement : de 613,9 mg, 709,8 mg et 267,5 mg. Les apports en fer se situaient à la limite inférieure de la normale (7,7 mg) chez les sujets âgés de plus de 66 ans. Les apports en vitamines A et C étaient satisfaisants, tandis qu’un risque de carence était observé pour les vitamines B1 et B2, dans le groupe des sujets âgés de 31 à 59 ans (0,17 mg et 0,58 mg). Conclusion. Ces observations suggèrent un effet négatif du confinement dans le domaine nutritionnel, justifiant des stratégies adaptées de supplémentation alimentaire, en vue de renforcer les capacités immunitaires dans la population exposée. Context & objective. Nutritional impact of lockdown due to the COVID-19 pandemic has not yet been studied in African environment. This study aimed to analyze the nutritional characteristics of active adults and the elderly Congolese to screen for possible deficiencies. Methods. The cross-sectional survey was carried out between April and May 2020, during the 2nd Covid-19 lockdown. Few households in Bacongo (Brazzaville) were randomly recruited and interviewed, using a quantitative food-type questionnaire, adressing the nature and quantity of food consumed throughout the day. Daily intakes were measured and reported as percentage of energy supplied respectively by carbohydrates, lipids and proteins; as well as trace elements, and few vitamins. Results. The overall average nutritional value around 2123.5 ± 494.5 kcal reflects an insufficient intake; specifically for proteins (33,5g/d) and fat (59,5g/d) requirements, except for carbohydrates (81,5%). The intakes of calcium (613.9 mg), phosphorus (709,8 mg), and magnesium (267,5 mg) met the recommended standards. Iron intakes were at the lower limit of normal (7.7 mg) in subjects aged more than 66 yrs to. Vitamin intakes were relevant for vitamins A and C, while slightly deficient in subjects aged 31-59 yrs for vitamins B1 and B2. Conclusion. The present observations suggest a negative nutritional impact of lockdown, highlighting the need for targeted nutritional strategies of food supplementation

Current and Future Experimental Strategies for Structural Analysis of Trichothecene Mycotoxins-A Prospectus

Fungal toxins, such as those produced by members of the order Hypocreales, have widespread effects on cereal crops, resulting in yield losses and the potential for severe disease and mortality in humans and livestock. Among the most toxic are the trichothecenes. Trichothecenes have various detrimental effects on eukaryotic cells including an interference with protein production and the disruption of nucleic acid synthesis. However, these toxins can have a wide range of toxicity depending on the system. Major differences in the phytotoxicity and cytotoxicity of these mycotoxins are observed for individual members of the class, and variations in toxicity are observed among different species for each individual compound. Furthermore, while diverse toxicological effects are observed throughout the whole cellular system upon trichothecene exposure, the mechanism of toxicity is not well understood. In order to comprehend how these toxins interact with the cell, we must first have an advanced understanding of their structure and dynamics. The structural analysis of trichothecenes was a subject of major interest in the 1980s, and primarily focused on crystallographic and solution-state Nuclear Magnetic Resonance (NMR) spectroscopic studies. Recent advances in structural determination through solution- and solid-state NMR, as well as computation based molecular modeling is leading to a resurgent interest in the structure of these and other mycotoxins, with the focus shifting in the direction of structural dynamics. The purpose of this work is to first provide a brief overview of the structural data available on trichothecenes and a characterization of the methods commonly employed to obtain such information. A summary of the current understanding of the relationship between structure and known function of these compounds is also presented. Finally, a prospectus on the application of new emerging structural methods on these and other related systems is discussed

Естетската функција на симболот во „Бели мугри“ од Рацин

Овој труд претставува анализа на естетската функција на симболот во песните од збирката „Бели мугри“ на Кочо Рацин. Теориски е образложена функцијата на симболот, нагласени се цитати и дефиниции за симболот коишто се поткрепени со примери. Успеавме да издвоиме симболи во сите дванаесет песни од збирката и да ги толкуваме тие симболи. По извршената анализа на песните, утврдивме дека симболот за тутунот е доминантен во песните од „Бели мугри“. Овој симбол го среќаваме во песните „Селска мака“; „Тутуноберачите“ и „Ленка“. Тутунот, всушност, ја симболизира горчината, непријатностите, маката и јадот. Ако го земеме предвид временскиот период во кој творел Рацин, а тоа е периодот меѓу двете светски војни (период исполнет со непријатности, горчини, тага, јад...), несомнено е дека Рацин бил инспириран од морално-патриотски побуди, од богатата револуционерна традиција и од ропството под кое се наоѓа Македонија

Etude "in situ" des effets de la température sur la biologie de la crevette d'eau douce Atyaphyra desmaresti Millet : cas particulier du bassin de rejet de la centrale thermique de La Maxe

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Cytoembryological studies on eastern galega (Galega orientalis Lam.) - a new papilionaceous plant.

Embryogenesis, microsporogenesis and pollen development in eastern galega (Galega orientalis Lam.) have been analysed. Generally, the embryogenesis in eastern galega is similar to that of goat’s rue (Galega officinalis L.). It is typical for eastern galega to form linear proembryos to the phase of 8 or 9 cells. The proper embryo develops from apical cells of the proembryo, while the remaining cells form the suspensor. The embryo of eastern galega typically forms a long, massive suspensor consisting of several irregular rows of cells on the side of the proper embryo and one large cell on the side of the micropyle. Suspensors were preserved in developing seeds possessing embryos with elongated cotyledons and a massive hypocotyl. In the initial phase of embryogenesis the endosperm is of a nuclear type. The transformation of the nuclear into cellular type of endosperm begins at the heartlike embryo phase and proceeds from the micropylar to chalazal end. Observations on the embryogenesis in eastern galega revealed the presence of degenerating ovules. Causes of degeneration were not analysed.Meiotic division in PMCs leads to the formation of microspore tetrads via simultaneous cytokinesis. Mature pollen grains are two-celled with well-formed sporoderm and three germ pores through which pollen tube can emerge

Draft of revitalization of the house using alternative energy conception

This Bachelor thesis Draft of revitalization of the house using alternative energy conception is focused on creating an investmen plan for fourty years old family house that does not meet the requirements for heat loss. This leads to high operation costs of the building, which will be reduced by the revitalization to the level of low-energy house. The theoretical part of the work is focused on the revitalization of residential buildings, as well as grants for the alternative resources and their use. In the practical part will be evaluated the current state of the building and will be proposed improvements. The second task will be characteristic of the geographical location of the house and technological equipment of it. There will be designed alternative energy sources. Individual variants will be matched by investment and operating costs. The result will be selecting the best options and their economic evaluation