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In this paper, we have studied the solar radiation data available at two meteorological stations located in the south of Tunisia. Measurements of global solar radiation on horizontal surface are compared to predictions made by different methods. The first method is based on Angström-Prescott formula which correlates relative global solar radiation H/H0 to corresponding relative duration of bright sunshine SS/SS0. The second method, a model due to Mechlouch et al., uses cloud cover N, the hours of the day t and the quantum of the year q. The third method, an empirical relation due to Sivkov, uses the monthly sunshine duration nm and the noon altitude of the sun h. The models are compared and tested on the basis of statistical error tests (MBE, RMSE, MPE and R2) and the results are presented.

The increase of ecology-economical indexes of mining industry processes is related largely to the improvement of existing and creation of new methods of conduct of explosive works. It is known that the labour intensiveness of explosion preparation during realization of openwork is 30– 40% from the general mining process, with the use of underground method the specific gravity of drilling-blasting works increases to 50–70%. Therefore a relevant task is the choice of the explosive materials providing on the one hand efficiency of technology, and with another – its ecological safety. Exploding composition represent the systems including explosive and unexplosive components chemically untied among themselves.

Cotton is one of the most important crops in the world. With the increasing scarce of global water resources, irrigation water will become a major limiting factor in cotton production. Deficit irrigation is an irrigation method which consumes less water than the normal evapotranspiration of crops. It is an effective water-saving method due to improved water use efficiency without sacrificing cotton yield and fiber quality. We summarized the effects of deficit irrigation on the growth and water use efficiency of cotton. The results showed that deficit irrigation promoted the transformation from vegetative growth to reproductive growth, reduced plant height, leaf area, and total biomass of cotton, and subsequently improved the harvest index, stem diameter and water use efficiency. Finally, based on the current research and combined with cotton production reality, the application and future development of deficit irrigation were proposed, which might provide theoretical guidance for the sustainable development of cotton plantation in arid areas.

With the increase in energy of the Large Hadron Collider to a centre-of-mass energy of 13 TeV for Run 2, events with dense environments, such as in the cores of high-energy jets, became a focus for new physics searches as well as measurements of the Standard Model. These environments are characterized by charged-particle separations of the order of the tracking detectors sensor granularity. Basic track quantities are compared between 3.2 fb$^{-1}$ of data collected by the ATLAS experiment and simulation of proton-proton collisions producing high-transverse-momentum jets at a centre-of-mass energy of 13 TeV. The impact of charged-particle separations and multiplicities on the track reconstruction performance is discussed. The efficiency in the cores of jets with transverse momenta between 200 GeV and 1600 GeV is quantified using a novel, data-driven, method. The method uses the energy loss, dE/dx, to identify pixel clusters originating from two charged particles. Of the charged particles creating these clusters, the measured fraction that fail to be reconstructed is $0.061 \pm 0.006 \textrm{(stat.)} \pm 0.014 \textrm{(syst.)}$ and $0.093 \pm 0.017 \textrm{(stat.)}\pm 0.021 \textrm{(syst.)}$ for jet transverse momenta of 200-400 GeV and 1400-1600 GeV, respectively. The European physical journal / C 77(10), 673 (2017). doi:10.1140/epjc/s10052-017-5225-7 Published by Springer, Berlin

Les forêts jouent un rôle de premier plan dans les cycles régionaux et mondiaux du carbone (C). Une évaluation détaillée des changements temporels et spatiaux dans les puits/sources de carbone des forêts chinoises est essentielle à l'estimation du budget national de carbone et peut aider à constituer des politiques de gestion durable des forêts pour le changement climatique. Dans cette étude, nous avons exploré les changements spatio-temporels des stocks de C de la biomasse forestière en Chine entre 1977 et 2008, en utilisant six périodes des données de l'inventaire forestier national. Selon la définition de l'inventaire forestier, la forêt chinoise a été classée en trois groupes : peuplement forestier, forêt économique et forêt de bambous. Nous avons estimé les stocks de biomasse forestière C pour chaque période d'inventaire en utilisant la méthode du facteur d'expansion continue de la biomasse (BEF) pour les peuplements forestiers et la méthode de la densité moyenne de la biomasse pour les forêts économiques et de bambou. En conséquence, les forêts chinoises ont accumulé une biomasse C (c'est-à-dire un puits de biomasse C) de 1 896 Tg (1 Tg=10(12) g) au cours de la période d'étude, avec 1 710, 108 et 78 Tg C dans les peuplements forestiers et les forêts économiques et de bambou, respectivement. Le puits annuel de C de la biomasse forestière était de 70,2 Tg C a(-1), compensant 7,8 % des émissions contemporaines de CO2 fossile dans le pays. Les résultats ont également montré que les forêts plantées ont fonctionné comme un puits de carbone persistant, séquestrant 818 Tg C et représentant 47,8 % du puits de carbone total dans les peuplements forestiers, et que les forêts âgées, moyennes et jeunes ont séquestré 930, 391 et 388 Tg C de 1977 à 2008. Nos résultats suggèrent que les forêts chinoises ont un grand potentiel en tant que puits de biomasse C à l'avenir en raison de sa grande superficie de forêts plantées avec une croissance jeune et une faible densité de C. Los bosques desempeñan un papel de liderazgo en los ciclos regionales y mundiales del carbono (C). La evaluación detallada de los cambios temporales y espaciales en los sumideros/fuentes de C de los bosques de China es fundamental para la estimación del presupuesto nacional de C y puede ayudar a constituir políticas de gestión forestal sostenible para el cambio climático. En este estudio, exploramos los cambios espacio-temporales en las poblaciones de biomasa forestal C en China entre 1977 y 2008, utilizando seis períodos de los datos del inventario forestal nacional. De acuerdo con la definición del inventario forestal, el bosque de China se clasificó en tres grupos: bosque forestal, bosque económico y bosque de bambú. Estimamos las existencias de biomasa forestal C para cada período de inventario utilizando el método del factor de expansión continua de biomasa (BEF) para los rodales forestales y el método de densidad media de biomasa para los bosques económicos y de bambú. Como resultado, los bosques de China han acumulado biomasa C (es decir, sumidero de biomasa C) de 1896 Tg (1 Tg=10(12) g) durante el período de estudio, con 1710, 108 y 78 Tg C en rodales forestales, y bosques económicos y de bambú, respectivamente. El sumidero anual de biomasa forestal C fue de 70.2 Tg C a (-1), compensando el 7.8% de las emisiones contemporáneas de CO2 fósil en el país. Los resultados también mostraron que los bosques plantados han funcionado como un sumidero de C persistente, secuestrando 818 Tg C y representando el 47.8% del sumidero total de C en los rodales forestales, y que los bosques viejos, medianos y jóvenes han secuestrado 930, 391 y 388 Tg C de 1977 a 2008. Nuestros resultados sugieren que los bosques de China tienen un gran potencial como sumidero de biomasa C en el futuro debido a su gran área de bosques plantados con crecimiento joven y baja densidad de C. Forests play a leading role in regional and global carbon (C) cycles. Detailed assessment of the temporal and spatial changes in C sinks/sources of China's forests is critical to the estimation of the national C budget and can help to constitute sustainable forest management policies for climate change. In this study, we explored the spatio-temporal changes in forest biomass C stocks in China between 1977 and 2008, using six periods of the national forest inventory data. According to the definition of the forest inventory, China's forest was categorized into three groups: forest stand, economic forest, and bamboo forest. We estimated forest biomass C stocks for each inventory period by using continuous biomass expansion factor (BEF) method for forest stands, and the mean biomass density method for economic and bamboo forests. As a result, China's forests have accumulated biomass C (i.e., biomass C sink) of 1896 Tg (1 Tg=10(12) g) during the study period, with 1710, 108 and 78 Tg C in forest stands, and economic and bamboo forests, respectively. Annual forest biomass C sink was 70.2 Tg C a(-1), offsetting 7.8% of the contemporary fossil CO2 emissions in the country. The results also showed that planted forests have functioned as a persistent C sink, sequestrating 818 Tg C and accounting for 47.8% of total C sink in forest stands, and that the old-, mid- and young-aged forests have sequestrated 930, 391 and 388 Tg C from 1977 to 2008. Our results suggest that China's forests have a big potential as biomass C sink in the future because of its large area of planted forests with young-aged growth and low C density. تلعب الغابات دورًا رائدًا في دورات الكربون الإقليمية والعالمية. يعد التقييم التفصيلي للتغيرات الزمنية والمكانية في أحواض/مصادر غابات الصين أمرًا بالغ الأهمية لتقدير الميزانية الوطنية للغابات ويمكن أن يساعد في تشكيل سياسات الإدارة المستدامة للغابات من أجل تغير المناخ. في هذه الدراسة، استكشفنا التغيرات المكانية والزمانية في مخزونات الكتلة الحيوية للغابات C في الصين بين عامي 1977 و 2008، باستخدام ست فترات من بيانات الجرد الوطني للغابات. وفقًا لتعريف جرد الغابات، تم تصنيف غابات الصين إلى ثلاث مجموعات: الغابات، والغابات الاقتصادية، وغابات الخيزران. قمنا بتقدير مخزونات الكتلة الحيوية للغابات C لكل فترة جرد باستخدام طريقة عامل التوسع المستمر للكتلة الحيوية (BEF) لمواقف الغابات، وطريقة متوسط كثافة الكتلة الحيوية للغابات الاقتصادية وغابات الخيزران. ونتيجة لذلك، تراكمت لدى غابات الصين الكتلة الحيوية ج (أي بالوعة الكتلة الحيوية ج) من 1896 تيراغرام (1 تيراغرام=10(12) ز) خلال فترة الدراسة، مع 1710 و 108 و 78 تيراغرام ج في منصات الغابات، والغابات الاقتصادية وغابات الخيزران، على التوالي. بلغ حوض الكتلة الحيوية السنوي للغابات 70.2 تيراغرام من الكربون (-1)، مما عوض 7.8 ٪ من انبعاثات ثاني أكسيد الكربون الأحفورية المعاصرة في البلاد. وأظهرت النتائج أيضًا أن الغابات المزروعة كانت بمثابة بالوعة ج ثابتة، حيث احتجزت 818 تيراغرام ج وتمثل 47.8 ٪ من إجمالي بالوعة ج في الغابات، وأن الغابات القديمة والمتوسطة والصغيرة قد احتجزت 930 و 391 و 388 تيراغرام ج في الفترة من 1977 إلى 2008. تشير نتائجنا إلى أن غابات الصين لديها إمكانات كبيرة حيث تغرق الكتلة الحيوية C في المستقبل بسبب مساحتها الكبيرة من الغابات المزروعة مع نمو في سن الشباب وانخفاض كثافة C.

The phytoplankton in the inner Neva Estuary is described from data obtained from 1996 to 2000. The seasonal dynamics of the phytoplankton biomass are characterized by a bimodal curve with a summer maximum. The average seasonal biomass was approximately3 mg l-1, the maximum biomass was 8-11 mg l-1. The species composition and quantitative parameters were compared to those observed in the 1980s. A notable, nearly 1.5-2 fold, increase in the biomass in the summer-autumn period and the predominance of Oscillatoria species among the blue-greenalgae were observed. A decline in the nutrient load in the water body at the end of the 1990s appeared to be insufficient to bringabout a decrease in the proportion of Oscillatoria algae in the total species composition or a decline in the biomass ofthe entire phytoplankton community. In 2000 a certain change in the structural composition of the phytoplankton complex was noted. Species that had been predominantin the 1980s and had lost their advantage in the early 1990s, regained their earlier status.