Natural Regeneration of Severely Degraded Terrestrial Arid Ecosystems Needs More Than Just Removing the Cause of the Degradation

Rangelands cover over 75% of Kuwait’s total land area. Most of these rangelands are severely degraded because of overgrazing, poor anthropic utilization, and mismanagement. Restoring natural rangelands is a way to increase forage productivity, enhance biodiversity, and achieve sustainable development. When degradation has not reached the point of irreversibility, natural restoration through resting is one of the best low-cost restoration techniques. This study evaluated the effect of natural restoration on vegetation cover and species richness in the desert rangelands of Kuwait. The studied rangeland was a completely fenced area of 1 km2. The percent of vegetation was measured using the line- intercept method. The cover of perennial species was the same in fenced and unfenced areas (0%), but annual species cover was 19.67% in fenced areas and 6% in unfenced areas. There was no significant difference in the contribution to the total cover of the dominant invasive species Stipa capensis between fenced (90%) and unfenced areas (83%). All recorded species are therophytes, which raises the disturbance index to 100%. This therophytization demonstrates an imbalance in the rangeland ecosystem and desertification due to the high anthropozoogene pressure. Under such a severely degraded ecosystem, natural restoration cannot restore vegetation. Reintroducing native species including Helianthemum lipii, Haloxylon salicornicum, Rhanterium epapposum, and Calligonum comosum, is required to restore the ecosystem, facilitate the growth of annual palatable species, and enhance the flora diversity

The EYA Tyrosine Phosphatase Activity Is Pro-Angiogenic and Is Inhibited by Benzbromarone

Eyes Absents (EYA) are multifunctional proteins best known for their role in organogenesis. There is accumulating evidence that overexpression of EYAs in breast and ovarian cancers, and in malignant peripheral nerve sheath tumors, correlates with tumor growth and increased metastasis. The EYA protein is both a transcriptional activator and a tyrosine phosphatase, and the tyrosine phosphatase activity promotes single cell motility of mammary epithelial cells. Since EYAs are expressed in vascular endothelial cells and cell motility is a critical feature of angiogenesis we investigated the role of EYAs in this process. Using RNA interference techniques we show that EYA3 depletion in human umbilical vein endothelial cells inhibits transwell migration as well as Matrigel-induced tube formation. To specifically query the role of the EYA tyrosine phosphatase activity we employed a chemical biology approach. Through an experimental screen the uricosuric agents Benzbromarone and Benzarone were found to be potent EYA inhibitors, and Benzarone in particular exhibited selectivity towards EYA versus a representative classical protein tyrosine phosphatase, PTP1B. These compounds inhibit the motility of mammary epithelial cells over-expressing EYA2 as well as the motility of endothelial cells. Furthermore, they attenuate tubulogenesis in matrigel and sprouting angiogenesis in the ex vivo aortic ring assay in a dose-dependent fashion. The anti-angiogenic effect of the inhibitors was also demonstrated in vivo, as treatment of zebrafish embryos led to significant and dose-dependent defects in the developing vasculature. Taken together our results demonstrate that the EYA tyrosine phosphatase activity is pro-angiogenic and that Benzbromarone and Benzarone are attractive candidates for repurposing as drugs for the treatment of cancer metastasis, tumor angiogenesis, and vasculopathies

Relative Differences between Nonlinear and Equivalent-Linear 1-D Site Response Analyses

This study investigates the conditions for which one-dimensional (1-D) nonlinear (NL) site response analysis results are distinct from equivalent-linear (EL) results and provides guidance for predicting when differences are large enough to be of practical significance. Relative differences in spectral accelerations and Fourier amplitudes computed from NL and EL analyses are assessed for a range of site conditions and for suites of input motions appropriate for active crustal and stable continental regions. Among several considered parameters, EL/NL differences are most clearly dependent on shear strain index (I-gamma), defined as the ratio of input motion peak velocity to time-averaged shear-wave velocity in the top 30 m of the soil profile. For small I-gamma (generally under 0.03%), EL and NL results are practically identical, whereas at larger strains, differences can be significant for frequencies >0.3 Hz. Frequency-dependent I-gamma, values are recommended for conditions above which NL analyses are preferred to EL.ope

Topographic amplification factors for Japan using 2D finite element analysis

It is widely recognized that seismic waves can be amplified or deamplified due to constructive or destructive interference when the waves encounter surface topographic irregularities such as valleys, peaks, and plateaus. These phenomena, termed as topographic effects, are particularly important for the seismically-induced landslide hazard assessment. This study examines influence of various factors such as peak ground acceleration, slope angle, relative elevation, and curvature on ground motion amplifications by performing finite element analyses with realistic topography data (from ASTER Global Digital Elevation Model Version 2) and real ground motions for Japan obtained from the National Research Institute for Earth Science and Disaster Prevention (NIED) strong-motion seismograph networks. The results show that topographic amplification factors (defined as the spectral acceleration estimated for the topography model divided by that estimated for the free-field) are most sensitive to relative elevation and curvature. The predictive models are proposed using those two factors as variables