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The capacity of green roofs to intercept rainfall, and consequently store and slow runoff resulting in a reduction in flood risk, is one of their main advantages. In this review, previous research related to the influence of green roofs on the hydrological cycle is examined with a special focus on studies for Mediterranean climate conditions (Csa and Csb according to the Köppen–Geiger climate classification). This climate is characterized by short and intense rainfall occurrences which, along with the increased area of impervious surface on Mediterranean regions, intensify the risk of flooding, particularly in the cities. The analysis covers the variables rainfall retention (R, %), runoff delay (RD, min or h), peak delay (PD, min or h), peak attenuation (PA, %), and runoff coefficient (RC, −), in relation to physical features of the green roof such as layers, substrate depth, slope, and vegetation, as well as, weather conditions, such as monthly temperature and monthly precipitation. Following a statistical analysis, some patterns for the average rainfall retention (%) were found in the published literature for green roofs under Mediterranean climate conditions—namely, that the most significant variables are related to the substrate depth, the existence of certain layers (root barrier, drainage layer), the origin of the vegetation, the types of green roofs (extensive, semi-intensive, intensive), and the precipitation and temperature of the location. Moreover, a multivariate analysis was conducted using multiple linear regression to identify the set of green roof features and weather conditions that best explain the rainfall retention (%), taking into consideration not only the studies under Mediterranean conditions but all climates, and a similar pattern emerged. Recommendations for future research include addressing the effect of physical features and weather conditions on the other variables (RD, PD, PA, RC) since, although present in some studies, they still do not provide enough information to reach clear conclusions. [ABSTRACT FROM AUTHOR]

This paper reports on the nonlinear static analysis of 2D concrete structures using a non-conventional finite element formulation. The nonlinear behavior of the material is modelled with a continuum non-local and isotropic damage model. While the material’s behavior is linear elastic, a pure hybrid-displacement Trefftz formulation is adopted. From the point where the concrete assumes a nonlinear behavior, this approach degenerates into a hybrid-displacement formulation. The computational performance is tested by means of two numerical examples which show that the proposed model predicts correctly the global behavior of the structures. [Copyright &y& Elsevier]

Abstract: This communication reports on the nonlinear analysis of 2D concrete structures using an hybrid-mixed stress formulation and continuum damage mechanics. The finite element model adopted is based on the direct and independent approximation of three fields: the stress and displacement fields in the domain of each element and the displacement field on the static boundary. The nonlinear behavior of the material is modelled using both a local and nonlocal isotropic damage model. Two numerical examples are presented to illustrate and validate the use of such numerical technique. [Copyright &y& Elsevier]

Background: Stroke is a major cause of severe and long-term disability in adult individuals. Treatment of this disease is limited by the narrow therapeutic window in which intervention is crucial. An alternative therapy for stroke could be cellular growth factors, which participate in several pathways that mediate neuronal cell death., Methods: We evaluated the neuroprotective ability of different doses of granulocyte colonystimulating factor (G-CSF; 5, 50 and 100 μg/kg/day) in the mouse model of global cerebral ischemia induced by bilateral occlusion of the common carotid arteries for 80 minutes. The control group received vehicle (5% glucose solution) and the treated group was administered with G-CSF at two postsurgery time-points: immediately after and 24 hours after. Subsequently, muscle strength, leukocyte count, infarcted cortical area, and apoptosis/TUNEL were evaluated., Results: The global ischemia promoted an impairment of the strength (16%) and a cerebral infarction (0.437±0.08 cm2) which were accompanied by apoptosis evaluated by TUNEL in control mice. In mice treated with G-CSF the strength function was maintained, the infarcted area (~70%) and apoptosis were decreased in a similar magnitude in all treated groups. Accordingly, the cytokine activities were confirmed by blood leukocyte count that was increased approximately 2-fold than that observed in the control group., Conclusion: The results indicate a neuroprotective effect of G-CSF, even in small doses, in mice subjected to global cerebral ischemia, thereby reducing the neurofunctional impairment caused by stroke, when considering the maintenance of muscle strength in the treated animals., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)