Environmental Science and Pollution Research - Agriculture faces many challenges such as climate change, droughts, and salinity, which requires urgent interventions for fast adaptation and... 相似文献
Chemically mediated communication is common in spiders but has been poorly studied in burrowing tarantulas. This study aimed
to determine whether chemical cues influence the behaviour of females of Brachypelma vagans, a Mexican species of tarantula, during encounters with previously inhabited burrows or with extracts from the silk of conspecific
females. In laboratory choice tests, female tarantulas entered a burrow that had previously been inhabited by a conspecific
female significantly more frequently than a burrow that had never been inhabited. The identity of the previous inhabitant
also affected the number of spiders that chose to enter a burrow. Spiders were quicker to choose and enter a burrow previously
inhabited by themselves than a burrow previously inhabited by a conspecific or a burrow that had not been previously inhabited.
Hexane, methanol and dichloromethane extracts of conspecific silk elicited different responses from female tarantulas when
extracts were placed on filter paper disks at one end of an experimental arena with a control filter paper disk, on to which
the corresponding solvent alone had been pipetted, placed on the other end of the arena. Spiders showed the strongest responses
to hexane extracts of silk, with a significant preference to move towards the hexane extract and a significantly greater period
of time spent in proximity to the hexane extract compared to the control disk. Overall and in contrast to expectations, tarantulas
were most strongly attracted to the cues left by other conspecific females. As encounters between B. vagans females usually lead to aggression and mortality of one of the participants, we conclude that chemical cues are not signals
that are deliberately released by burrow-inhabiting females but may inadvertently escape and cannot be easily suppressed. 相似文献
Environmental Science and Pollution Research - The aim of our study was to analyze the associations between anthropometric measures and high blood pressure (HBP) in Algerian patients. A... 相似文献
Ephedra alata, known as a medicinal plant in China, was used in this study as aqueous extract from aerial parts, for diabetes mellitus treatment. This study was carried out on two parts, in vitro, we tested the effect of the studied extract on the inhibition of α-glucosidase and α-amylase activities, and in vivo on Wistar male rats receiving alloxan intraperitoneally at a rate of 125 mg/kg. Extract (100, 200, and 300 mg/kg of body weight) was administrated for 28 days by oral gavage. Blood glucose, amylase, lipase, and lipid profile level were determined. Oxidative stress was evaluated by enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and by estimation of lipid peroxidation and protein carbonyl (PC) level. Histopathological changes in pancreas were investigated under photonic microscopy using immunohistochemical procedure. Our findings showed that aqueous extract inhibited in vitro both α-glucosidase and α-amylase activities and its use in vivo at 300 mg/kg of body weight restored pancreas weight and weight gain, ameliorated significantly (p ? 0.05) biochemical parameters; it prevented the increase in lipid and protein oxidation and the decrease in enzymatic and non-enzymatic defense system. Histological study of treated animals showed a comparable healed regeneration of beta cells.
Environmental Science and Pollution Research - Colorectal carcinoma (CRC) is the second most common cancer diagnosed in Algeria. The incidence and the mortality rate of CRC have increased so that... 相似文献
This work is dedicated to the removal of free cyanide from aqueous solution by oxidation with hydrogen peroxide H2O2 catalyzed by neutral activated alumina. Effects of initial molar ratio [H2O2]0/[CN?]0, catalyst amount, pH, and temperature on cyanide removal have been examined. The presence of activated alumina has increased the reaction rate showing thus, a catalytic activity. The rate of removal of cyanides increases with rising initial molar ratio [H2O2]0/[CN?]0 but decreases at pH 10 to 12. Increasing the alumina amount from 1.0 to 30 g/L has a beneficial effect, and increasing the temperature from 20 °C to 35 °C improves cyanide removal. The kinetics of cyanide removal has been found to be of pseudo-first-order with respect to cyanide and the rate constants have been determined. 相似文献
Indirect soil pollution by heavy metals and organics may occur when sewage sludge is used as fertilizer. It is essential to define the nature and amounts of pollutants contained in sewage sludge in order to assess environmental risk. Here, we present results from a one-year monitoring of herbicides (glyphosate, diuron and atrazine) and their major degradates in sewage sludge sampled from three wastewater treatment plants and one composting unit in the vicinity of Versailles, France. The concentrations of these compounds were determined, as well as these of the surfactant nonylphenol. We demonstrated the presence of glyphosate and aminomethylphosphonic acid at the mg kg(-1) (dry matter) level in all samples. Diuron was detected at the microg kg(-1) (d.m.) level, whereas its degradate and triazine compounds were below the limits of quantification. Nonylphenol amounts were higher than the future European limit value of 50 mg kg(-1) (d.m.). 相似文献
This study aims to monitor the arid Algerian High Plateaus, a key region for pastoral activities which has suffered harsh and widespread degradation from the eighties. This area is not sufficiently known by the international scientific community. For this purpose, we considered phytoecological inventories and thematic maps that have been carried out during 30 years. Available data for the study are vegetation maps derived from aerial photographs (1975-1978) and from satellite imagery (2006). The parameters considered include vegetation, flora, and soil surface properties. The study area is part of the ROSELT/OSS (ROSELT: Réseau d'Observatoires de Surveillance Ecologique à Long Terme (Long Term Ecological Monitoring Observatories Network); OSS: Observatory of the Sahara and the Sahel) network observatory (OSS 2008). To assess land degradation, we used landscape ecology parameters. These include the number and surface area of vegetation units, synthesized by the large patch index and the Shannon landscape diversity index. All parameters reflect an increase in landscape heterogeneity. The largest decline is observed for Stipa tenacissima vegetation units constituting 2/3 of the landscape in 1978 and occupied just 1/10 in 2006. Vegetation units linked to degradation, such those dominated by Salsola vermiculata, inexistent in 1978, now dominate the steppe. Another result of the ongoing landscape degradation on the plateaus between 1975 and 2006 is the decrease of vegetation cover. In 1978, 1/3 of rangelands only had low vegetation covers, inferior to 15%. Presently 9/10 present the same class cover. This can be explained by severe spells of drought combined by an exponential rise of livestock during the last 30 years. This has in turn greatly undermined the fodder potential of the steppe. Results suggest that the "greening-up" described by several authors in the Sahel over the last 40 years is not observed in the Algerian, nor in the North African steppes. On the contrary, the desertification is still ongoing and the threshold of irreversibility seems to be imminent. 相似文献