Rainfall patterns of Algerian steppes and the impacts on natural vegetation in the 20~(th) century

Since 1960, the steppe regions of North Africa have been subject to an increasing desertification, including the degradation of traditional pastures. The initially dominant species(Artemisia herba-alba, Lygeum spartum and Stipa tenacissima) declined and were progressively replaced by other species(Atractylis serratuloides and Salsola vermiculata) that are more tolerant to the new conditions. It is not clear whether these changes are due to anthropogenic reasons or climatic determinism. We have carried out a statistical analysis of the climate to detect putative rainfall changes during the 20~(th) century in the Algerian steppes based on data from 9 meteorological stations, including 2 Saharan stations(El Oued and Touggourt), 3 pre-Saharan stations(Biskra, Laghouat and Ain Sefra) and 4 steppe stations(Djelfa, Saida, Méchéria and El-Bayadh) located in the arid high plains, which represent the bioclimate diversities of the region. Previous studies suggested that significant rainfall changes for the 20~(th) century only had records in the south of the Oran region. Most of the studies, however, looked at restricted territories over limited periods, and did not integrate the rainiest period 2004–2014. Our work is designed to integrate all the longest time series of meteorological data available for the steppe regions of Algeria. Our results confirm the spatial rainfall distribution(significant rainfall changes only recorded in the southwestern region) evidenced by previous studies, and reveal a decreasing rainfall gradient from northeastern to southwestern Algeria. Moreover, the results reveal a trend of significant decrease of rainfall in the southern Oran region, marked by two drought periods in 1980–1985 and 1999–2003. However, with the exception of the southwestern region, rainfall overall has not declined since the beginning of the 20~(th) century. While less marked in other regions, the drought appear to have affected all territories of the Algerian steppe. Consequently, our study implies that the climate was not a leading influence in the on-going degradation of the vegetation cover of steppe landscapes. Such a vegetation evolution thus appears to be have been determined more by human activities than by climate forcing.     

Real-time assays for detection of Phytophthora spp. and identification of an avr3a gene variant

Journal of Plant Diseases and Protection - A study was carried out for identification and detection of Phytophthora spp. from soil and plant samples, collected from Solanaceous crops in Egypt and...     

Assessment of short-term memory in Arabic speaking children with specific language impairment

Children with Specific Language Impairment (SLI) may have some kind of memory disorder that could increase their linguistic impairment. This study assessed the short-term memory skills in Arabic speaking children with either Expressive Language Impairment (ELI) or Receptive/Expressive Language Impairment (R/ELI) in comparison to controls in order to estimate the nature and extent of any specific deficits in these children that could explain the different prognostic results of language intervention. Eighteen children were included in each group. Receptive, expressive and total language quotients were calculated using the Arabic language test. Assessment of auditory and visual short-term memory was done using the Arabic version of the Illinois Test of Psycholinguistic Abilities. Both groups of SLI performed significantly lower linguistic abilities and poorer auditory and visual short-term memory in comparison to normal children. The R/ELI group presented an inferior performance than the ELI group in all measured parameters. Strong association was found between most tasks of auditory and visual short-term memory and linguistic abilities. The results of this study highlighted a specific degree of deficit of auditory and visual short-term memories in both groups of SLI. These deficits were more prominent in R/ELI group. Moreover, the strong association between the different auditory and visual short-term memories and language abilities in children with SLI must be taken into account when planning an intervention program for these children.     

Effect of Different Combinations of Cryoprotectants on In Vitro Maturation of Immature Buffalo (Bubalus bubalis) Oocytes Vitrified by Straw and Open‐Pulled Straw Methods

This study was designed to evaluate effects of different combinations of cryoprotectants on the ability of vitrified immature buffalo oocytes to undergo in vitro maturation. Straw and open‐pulled straw (OPS) methods for vitrification of oocytes at the germinal vesicle stage also were compared. The immature oocytes were harvested from ovaries of slaughtered animals and were divided into three groups: (i) untreated (control); (ii) exposed to cryoprotectant agents (CPAs); or (iii) cryopreserved by straw and OPS vitrification methods. The vitrification solution (VS) consisted of 6 m ethylene glycol (EG) as the standard, control vitrification treatment, and this was compared with 3 m EG + 3 m dimethyl sulfoxide (DMSO), 3 m EG + 3 m glycerol, and 3 m DMSO + 3 m glycerol. Cryoprotectants were added in two steps, with the first step concentration half that of the second (and final) step concentration. After warming, oocyte samples were matured by standard methods and then fixed and stained for nuclear evaluation. Rates of MII oocytes exposed to CPAs without vitrification were lower (54.3 ± 1.9% in EG, 47.5 ± 3.4% in EG + DMSO, 36.8 ± 1.2% in EG + glycerol and 29.9 ± 1.0% in DMSO + glycerol; p < 0.05) than for the control group (79.8 ± 1.3%). For all treatments in each vitrification experiment, results were nearly identical for straws and OPS, so all results presented are the average of these two containers. The percentages of oocytes reaching telophase‐I or metaphase‐II stages were lower in oocytes cryopreserved using all treatments when compared with control. However, among the vitrified oocytes, the highest maturation rate was seen in oocytes vitrified in EG + DMSO (41.5 ± 0.6%). Oocytes cryopreserved in all groups with glycerol had an overall low maturation rate 19.0 ± 0.6% for EG + glycerol and 17.0 ± 1.1% for DMSO + glycerol. We conclude that the function of oocytes was severely affected by both vitrification and exposure to cryoprotectants without vitrification; the best combination of cryoprotectants was EG + DMSO for vitrification of immature buffalo oocytes using either straw or OPS methods.     

Host plants record for tomato leaf miner Tuta absoluta (Meyrick) in Sudan

This paper presents the results from a survey that was carried out to determine the host plants of tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in five States in Sudan. This survey was carried out in greenhouses and open‐field vegetable production areas between the years 2011 and 2014 using pheromone traps. The survey showed that the main host plant of T. absoluta is tomato (Lycopersicon esculentum), but it also attacks potato (Solanum tuberosum), eggplant (S. melongena) Jimson weed (Datura stramonium) and S. dubium in the family Solanaceae, and broad bean (Vicia faba) and alfalfa plant (Medicago sativa) in the family Fabaceae. This paper is the first record of the following plans being hosts for T. absoluta: Watermelon (Citrullus lanatus) in the family Cucurbitaceae, Physic nut (Jatropha curcas) in the family Euphorbiaceae, spiny amaranth (Amaranthus spinosus) in the family Amaranthaceae, Ramtouk (Xanthium brasilicum) in the family Asteraceae and S. dubium. The study showed that the leafminer male numbers and the symptoms were significantly increased in S. melongena and S. dubium after severe damage and complete loss of the main host, the tomato crop and these two species may be the preferred alternative host plants.     

Effect of phase transformation on physical and biological properties of PVA/CaFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanocomposite

The thermal treatment method was employed to achieve higher homogeneity of calcium ferrite (CaFe2O4) and Poly (vinyl alcohol) (PVA) nanocomposites. The influences of phase transformation on physical and biological properties of calcined specimens were investigated by various experimental techniques including X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), high resolution Field emission scanning electron microscope (FESEM) and Fourier transform infrared spectroscopy (FT-IR). Heat treatment was conducted at temperatures between 723 and 923 K, so that a phase transformation occurred from cubic to orthorhombic spinel structure at 923 K. The chemical analysis of the PVA/CaFe₂O₄ nanocomposite was performed by energy dispersion X-ray analysis (EDXA), demonstrated the PVA/CaFe₂O₄ nanocomposites contained the elements of C, Ca, Fe, and O. The formed nanocomposites exhibited ferromagnetic behaviors which were confirmed by using a vibrating sample magnetometer (VSM). The calcined specimens were carried out to an antimicrobial or antifungal test.     

Preparation of Chito-Oligomers by Hydrolysis of Chitosan in the Presence of Zeolite as Adsorbent

An increasing interest has recently been shown to use chitin/chitosan oligomers (chito-oligomers) in medicine and food fields because they are not only water-soluble, nontoxic, and biocompatible materials, but they also exhibit numerous biological properties, including antibacterial, antifungal, and antitumor activities, as well as immuno-enhancing effects on animals. Conventional depolymerization methods of chitosan to chito-oligomers are either chemical by acid-hydrolysis under harsh conditions or by enzymatic degradation. In this work, hydrolysis of chitosan to chito-oligomers has been achieved by applying adsorption-separation technique using diluted HCl in the presence of different types of zeolite as adsorbents. The chito-oligomers were retrieved from adsorbents and characterized by differential scanning calorimetry (DSC), liquid chromatography/mass spectroscopy (LC/MS), and ninhydrin test.     

Effects of Biochar and Phosphorus Fertilizers on Phosphorus Fractions,Wheat Yield and Microbial Biomass Carbon in Vertic Torrifluvents

The present work was carried out to investigate the effect of biochar and phosphorus (P) fertilizer application, on phosphorus fractions, soil microbial biomass carbon in a Vertisol during two seasons for wheat in field experiments. Phosphorus was added at 0%, 50%, 100% and 150% P of recommended P fertilizers, with or without biochar at a rate of 10 t h^?1 arranged in a randomized complete block design with three replicates. Results showed that the wheat grain yield increased by 56% to 69% in plots treated with the interaction of biochar and P mineral during the 2015 and 2016 growing seasons. Co-application of biochar with inorganic P produced up to 1.5 fold more microbial biomass C than either biochar or inorganic P applied alone. Sequential extraction of the biochar-treated with P revealed that HCl-P decreased, whereas others fractions increased with increasing P rate. The inorganic and organic P fractions were increased significantly when the biochar was combined with fertilizer P as compared to the biochar or inorganic P applied alone. The results of this study reveal that the co-application of biochar with inorganic P can be a promising strategy to improve soil productivity and soil quality in alkaline soil.