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Arid Mediterranean regions that shelter unique biodiversity are threatened by increasing anthropogenic pressures, such as urbanization, overgrazing and climate change. In Morocco, one of the main bush species in arid areas, the jujube (Ziziphus lotus), suffers from officially promoted programmes of removal. The Moorish tortoise (Testudo graeca soussensis) is threatened by such habitat loss. Like most animals, the Moorish tortoise must navigate between microhabitats to find essential feeding resources and thermal refuges. This study combined radio-tracking of free-ranging individuals, microhabitat temperature monitoring and transects in a range of habitats. Tortoises were found to depend on the occurrence of large and relatively abundant bushes to escape lethal overheating. Thus, (1) current official encouragements for the destruction of the jujube bushes should be reappraised; (2) habitat restoration relying on replanting jujube bush should be encouraged; and (3) large-scale monitoring of critical bush densities should be used to better organize conservation plans (protection and/or restoration of areas) for the Moorish tortoise.
Numerous hydrogenated molecules observed in comets and the interstellar medium present
nuclear spin isomers. The non-thermal ortho: para ratios
measured in space are believed to be of high diagnostic value, allowing remote measurement
of physical conditions prevailing in the past, such as the initial temperature associated
with a molecular formation or condensation. The lack of laboratory studies on interactions
at the gas-solid interface limits our current interpretation of observations. Recent
progress in nuclear spin conversion (NSC) dynamics are discussed in this paper. Results on
water and methane in cryogenic matrices illustrate the conversion mechanisms within the
condensed phase at very low temperatures. NSC of molecular hydrogen at the surface of 10 K
Amorphous Solid Water (ASW) shows surface mediated conversion processes for molecular
hydrogen. NSC involving molecular ices are discussed in the light of few recent studies,
including UV photodesorption investigations.
This work is based on a numerical study of particle transport and diffusion using ITER parameters. In particular, the effects of introducing a non-monotonic safety factor (NMSF) in the case of a reversed magnetic shear are shown. These results are compared with those found by using a monotonic safety factor (MSF). Double internal transport barriers are detected influencing the transport and diffusion of particles. The choices of the mode (m, n) and the m/n values play a dominant role for the particle diffusion, which leads to an improvement of the magnetic confinement.
The reversed magnetic shear is the most important factor in the study of the plasmas of a tokamak. In this paper we focus our research, as a first stage, on the control of the improved confinement regimes by studying the influence of the reversed shear on its quality in the plasma of a tokamak and especially in reducing the anomalous transport in ITER. Then we study the influence of the perturbation modes on the particle diffusion. At the end, a comparison between simulation results obtained using ITER and TEXT parameters is carried out.
Patterns of growth were studied between 1993 and 1996 in a population of Bibron's agama Agama impalearis from an arid area in the central Jbilet Mountains, western Morocco. Non-linear regressions were used to model snout–vent lengths (SVL) and body masses of individuals caught during 1993–94 against skeletochronology age estimates. The overlap between male and female asymptotic SVLs (A) was negligible demonstrating sexual dimorphism, although there was no evidence of differences in characteristic growth rates (k) between sexes (males: A = 119.43 ± 2.29 mm and k = 0.849 ± 0.09 [month-1], females: A = 108.59 ± 3.19 mm and k = 1.079 ± 0.162 [month-1]). Asymptotic body mass differed substantially between sexes (males: 71.2 ± 3.1 g, females: 45.8 ± 4.2 g), but corresponding characteristic growth rates were similar (0.753 ± 0.339 and 0.789 ± 0.623 [month-1], respectively). The mark–recapture method provided generally higher and more reliable asymptotic size estimates (using the logistic-by-length non-linear regression model) than the skeletochronology-based estimates. Growth parameters were also estimated on an individual year basis. Only male characteristic growth rate showed a significant year-to-year variation (0.010 ± 0.006 to 0.024 ± 0.007 [day-1]), although this may have been due to a lack of statistical power. Annual variation in the absolute growth rate was detected only in hatchlings (0.087 ± 0.018 to 0.273 ± 0.132 mm.day-1) and adult males (0.089 ± 0.030 to 0.206 ± 0.100 mm.day-1).
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