Subsurface drip irrigated potato (Solanum tuberosum L.) with saline water under Tunisian climate

Field experiment was conducted at the Higher Institute of Agronomy of Chott Meriem (Tunisia) during the growing season (2011/2012) to investigate the effects of water quality on water‘s dynamic in soil (water potential, soilcmoisture distribution, water’s stock in soil) and water use efficiency (WUE) to produce potato (Solanum tuberosum L.). Irrigation management treatments were fresh (1 dS m-1) and saline waters (4 dS m-1). Subsurface drip irrigation was used, a rate of 4 L h-1 applied at the same irrigation duration and interval. The results indicate that water content is more uniform using the saline water varies from 15 to 23% than treatment varies from 10 to 26%. The recorded changes occurred due to improving soil water distribution in root zone are explained by the increased salinity and the existence of a root system more intense level of treatment. Water quality has no direct effect on water use efficinency

Using Hydrus 2-D to assess the emitters optimal position for Eggplants under surface and subsurface drip irrigation

The main objective of the work is to assess the emitters optimal position for Eggplant crop (Solanum melongena L.) in a sandy loam soil irrigated with surface or subsurface drip irrigation systems, by means of field measurements and simulations carried out with Hydrus-2D model. Initially, the performance of the model is evaluated on the basis of the comparison between simulated soil water contents (SWC) and the corresponding measured in two plots, in which laterals with coextruded emitters are laid on the soil surface (T0) and at 20 cm depth (T20), respectively. In order to choose the best position of the lateral, the results of different simulation runs, carried out by changing the installation depth of the lateral (5 cm, 15 cm and 45 cm) were compared in terms of ratio between actual transpiration and total amount of water provided during the entire growing season (WUE). Experiments were carried out, from April to June 2007, at Institut Sup\ue9rieur Agronomique de Chott M\ue9riem (Sousse, Tunisia). In the two plots, plants were spaced 0.40 m along the row and 1.2 m between the rows. Each plot was irrigated by means of laterals with coextruded emitters spaced 0.40 m and discharging a flow rate equal to 4.0 l h-1 at a nominal pressure of 100 kPa. In each plot, spatial and temporal variability of SWCs were acquired with a Time Domain Reflectometry probe (Trime-FM3), on a total of four 70 cm long access tubes, installed along the direction perpendicular to the plant row, at distances of 0, 20, 40 and 60 cm from the emitter. Irrigation water was supplied, accounting for the rainfall, every 7-10 days at the beginning of the crop cycle (March-April) and approximately once a week during the following stages till the harvesting (May-June), for a total of 15 one-hour watering. To run the model, soil evaporation, Ep, and crop transpiration, Tp were determined according to the modified FAO Penman-Monteith equation and the dual crop coefficient approach, whereas soil hydraulics and rooting system parameters were experimentally determined. Simulated SWCs resulted fairly close to the corresponding measured at different distances from the emitter and therefore the model was able to predict SWCs in the root zone with values of the Root Mean Square Error generally lower than 4%. This result is consequent to the appropriate schematization of the root distribution, as well as of the root water uptake. Simulations also evidenced the contribute of soil evaporation losses when laterals are installed from the soil surface to a 20 cm depth, whereas significant water losses by deep percolation occured at the highest installation depth. The values of WUE associated to the different examined installation depths tend to a very slight increase when the position of the lateral rises from 0 to 15 cm and start to decrease for the higher depths

Magnetocaloric effect of monovalent K doped manganites Pr0.6Sr0.4−xKxMnO3 (x=0 to 0.2)

peer reviewedMagnetic and magnetocaloric properties are reported for polycrystalline monovalent potassium doped manganites Pr0.6Sr0.4−xKxMnO3 (x=0, 0.05, 0.1, 0.15 and 0.2) crystallized in orthorhombic structure with Pnma space group. The increasing K content shifts the paramagnetic to ferromagnetic transition temperature from 310 K for x=0 to 269 K for x=0.2. The magnetic entropy change under magnetic field variation of 2 T is found to be 1.95, 3.09, 2.89, 3.05 and 3.2 J/kgK for x varying from 0 to 0.2, respectively. The highest relative cooling power of 102 J/kg is observed for the undoped sample. The sensitivity of magnetic entropy change to magnetic field is estimated by a local N(T) exponent exhibiting the characteristic temperature variation. Phenomenological universal curves of entropy change and Arrott plots confirm the second order phase transition

STRUCTURAL AND MAGNETIC STUDY OF PEROVSKITE MANGANITES OXIDES Pr 1-x x MnO 3

Abstract Structural and magnetic properties in a self doped Pr 1-x x MnO 3 system are investigated. X-ray diffraction patterns show that samples with composition range 0.0-0.3 crystallize in orthorhombic perovskite structure with Pbnm space group. Our samples exhibit an antiferromagnetic behavior at low temperature. The temperature ordering as a function of the vacancy content remains constant, however the magnetization magnitude at low temperature (T = 10 K) increases with increasing deficiency content

Splitting Arabic Texts into Elementary Discourse Units

International audienceIn this article, we propose the first work that investigates the feasibility of Arabic discourse segmentation into elementary discourse units within the segmented discourse representation theory framework. We first describe our annotation scheme that defines a set of principles to guide the segmentation process. Two corpora have been annotated according to this scheme: elementary school textbooks and newspaper documents extracted from the syntactically annotated Arabic Treebank. Then, we propose a multiclass supervised learning approach that predicts nested units. Our approach uses a combination of punctuation, morphological, lexical, and shallow syntactic features. We investigate how each feature contributes to the learning process. We show that an extensive morphological analysis is crucial to achieve good results in both corpora. In addition, we show that adding chunks does not boost the performance of our system

From community approaches to single-cell genomics: the discovery of ubiquitous hyperhalophilic Bacteroidetes generalists

The microbiota of multi-pond solar salterns around the world has been analyzed using a variety of culture-dependent and molecular techniques. However, studies addressing the dynamic nature of these systems are very scarce. Here we have characterized the temporal variation during 1 year of the microbiota of five ponds with increasing salinity (from 18% to >40%), by means of CARD-FISH and DGGE. Microbial community structure was statistically correlated with several environmental parameters, including ionic composition and meteorological factors, indicating that the microbial community was dynamic as specific phylotypes appeared only at certain times of the year. In addition to total salinity, microbial composition was strongly influenced by temperature and specific ionic composition. Remarkably, DGGE analyses unveiled the presence of most phylotypes previously detected in hypersaline systems using metagenomics and other molecular techniques, such as the very abundant Haloquadratum and Salinibacter representatives or the recently described low GC Actinobacteria and Nanohaloarchaeota. In addition, an uncultured group of Bacteroidetes was present along the whole range of salinity. Database searches indicated a previously unrecognized widespread distribution of this phylotype. Single-cell genome analysis of five members of this group suggested a set of metabolic characteristics that could provide competitive advantages in hypersaline environments, such as polymer degradation capabilities, the presence of retinal-binding light-activated proton pumps and arsenate reduction potential. In addition, the fairly high metagenomic fragment recruitment obtained for these single cells in both the intermediate and hypersaline ponds further confirm the DGGE data and point to the generalist lifestyle of this new Bacteroidetes group.This work was supported by the projects CGL2012-39627-C03-01 and 02 of the Spanish Ministry of Economy and Competitiveness, which were also co-financed with FEDER support from the European Union. TG group research is funded in part by a grant from the Spanish Ministry of Economy and Competitiveness (BIO2012-37161), a grant from the Qatar National Research Fund grant (NPRP 5-298-3-086) and a grant from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC (grant agreement no. ERC-2012-StG-310325)

Još o toksičnosti kadmija - s posebnim osvrtom na nastanak oksidacijskoga stresa i na interakcije s cinkom i magnezijem

Discovered in late 1817, cadmium is currently one of the most important occupational and environmental pollutants. It is associated with renal, neurological, skeletal and other toxic effects, including reproductive toxicity, genotoxicity, and carcinogenicity. There is still much to find out about its mechanisms of action, biomarkers of critical effects, and ways to reduce health risks. At present, there is no clinically efficient agent to treat cadmium poisoning due to predominantly intracellular location of cadmium ions. This article gives a brief review of cadmium-induced oxidative stress and its interactions with essential elements zinc and magnesium as relevant mechanisms of cadmium toxicity. It draws on available literature data and our own results, which indicate that dietary supplementation of either essential element has beneficial effect under condition of cadmium exposure. We have also tackled the reasons why magnesium addition prevails over zinc and discussed the protective role of magnesium during cadmium exposure. These findings could help to solve the problem of prophylaxis and therapy of increased cadmium body burden.Iako je otkriven tek 1817. godine, kadmij je trenutačno jedan od najvažnijih onečišćivača životne i radne sredine. Štetno djeluje na bubrege, živčani sustav, kosti, reproduktivni sistem, a ima i genotoksične i karcinogene efekte. Nužna su dalja istraživanja vezana za mehanizme njegove toksičnosti, biomarkere efekata, kao i načine smanjenja rizika za zdravlje. Osim toga, do danas nije otkriven agens efikasan u terapiji trovanja kadmijem s obzirom na to da je kadmij intracelularni kation. U ovom radu dan je sažet pregled važnih mehanizama toksičnosti kadmija, kao što su nastanak oksidativnog stresa i interakcije s esencijalnim elementima, cinkom i magnezijem, na osnovi dostupnih literaturnih podataka, kao i naših ispitivanja koja upućuju na to da povećani unos navedenih esencijalnih elemenata pokazuje pozitivne efekte pri ekspoziciji kadmiju. Obrazložena je prednost suplementacije magnezijem pred suplementacijom cinkom i razmatrana preventivna uloga magnezija pri intoksikaciji kadmijem. Ovi su rezultati doprinos rješavanju problema profi lakse i terapije trovanja kadmijem

Europium substitution effects on structural, magnetic and magnetocaloric properties in La 0.5

We have investigated structural, magnetic and magnetocaloric properties of polycrystalline samples La0.5-xEuxCa0.5MnO3 (x=0 and 0.1). Rietveld refinement of the X-ray diffraction patterns show that our samples are single phase and crystallize in the orthorhombic structure with Pnma space group. Magnetization measurements versus temperature at a magnetic applied field of 500 Oe indicate that La0.4Eu0.1Ca0.5MnO3 sample exhibits a paramagnetic to ferromagnetic transition with decreasing temperature. Magnetic measurements reveal strong magnetocaloric effect in the vicinity of the Curie temperature TC. The parent compound shows a negative magnetic entropy change of ∆SM=−1.13Jkg−1K−1 at 220K and a positive magnetocaloric effects ∆SM=1Jkg−1K−1 at 150K under a magnetic applied field of 2T. La0.4Eu0.1Ca0.5MnO3 exhibits a maximum value of magnetic entropy change ∆SM=−1.15Jkg−1K−1 at 130K under an applied field of 2T and a large relative cooling power RCP with a maximum value of 72 J/kg