Evaluation of Seismic Performance of Buildings Constructed on Hillside Slope of Doronka Village-Egypt

Construction on the hillside slope is more challenging to the structural engineer, especially under seismic load due to the presence of a powerful earthquake in addition to the forces of sliding slope itself. Regarding the population growth and narrowness of available lands, people take hillside slopes to build their houses. One of the main sources of seismic vulnerability in Egypt is represented by the instability of slopes; therefore, this is a subject of great significance, particularly in view of the growing attention that has been recently dedicated to the reduction of seismic hazard. This paper evaluates the seismic performance of Doronka city buildings constructed on rocky hillside slope and its foundations system by studying base shear, acceleration, and displacements. The stability of the slope was first evaluated under seismic loads and then the stability of constructed buildings was checked on the hillside slope. The results of study show that these buildings will collapse if subjected to earthquake even if its peak ground acceleration (PGA) magnitude is less than 0.25 g, but the hillside slope remains stable within a high earthquake magnitude.

Sem and phylogenetic analysis of naturalized and cultivated Epidendrum in Hawaii

Naturalized populations of Epidendrum L. are found on a rocky hillside in Nuuanu-Pali and Olomana in the Koolau Mountains of Oahu, Hawaii. Scanning electron micrographs were taken to observe polymorphism among the pollinia, petals, leaves, and root tips of two Epidendrum specimens (one naturalized specimen from Nuuanu-Pali and one cultivated specimen in the greenhouse). SEM images of pollen from the naturalized Epidendrum revealed a length of 830.31 μm and a width of 462.58 μm. Pollen length from the cultivated cultivar, by comparison, was 724.60 μm and the width 276.17 μm. Differing cell structures on the lower surface of the petals were also observed. Polyhedral concave cells with numerous fossae (pits) were seen on the naturalized cultivar and elongated flattened cells on the cultivated one. Transections of the leaf of the naturalized specimen were much thinner (546.33 μm) compared to the thickness of the cultivated cultivar leaf (1505.83 μm), which contained more spongy parenchyma cells. A thinner root tip (1094.19 μm) was seen in the naturalized cultivar, as opposed to 1636.34 μm in the cultivated specimen. To compare relationships between these two specimens along with ten other unknown Epidendrum cultivars, we sequenced the plastid trnL-F gene region and conducted parsimony analysis among the naturalized Epidendrum from Nuuanu-Pali At least six changes separated these specimens into two clades. Shorter and longer plastid simple sequence repeats (cpSSR) from the rps16-trnK region support separation of the five Epidendrum genotypes evaluated into these two groups, including a naturalized Epidendrum from Olomana.

Bamboo, fire and flood: regeneration of Bambusa arnhemica (Bambuseae: Poaceae) after mass-flowering and die-off at contrasting sites in monsoonal northern Australia

Bambusa arnhemica F.Muell., a long-lived, gregarious-flowering and semelparous bamboo endemic to north-western Australia, occurs in remarkably disparate but somewhat fire-sheltered flood-prone riparian forest and rocky hillside vine-thickets, but not in adjacent fire-prone savannas. We investigated the response of B. arnhemica seedlings to fire and flood at two contrasting sites over 2.5 years following a mass-flowering and die-off event. Seedlings grew vigorously notwithstanding either prolonged inundation or total loss of above-ground parts to fire within their first year. However, there was no evidence that such disturbance promoted regeneration, and several veins of evidence suggest that B. arnhemica is fire-retardant and refugial rather than fire-promoting. We suggest that creation of canopy gaps by parental death is a more parsimonious and generalisable hypothesis for the evolution of gregarious semelparity in bamboos than the recently advanced bamboo fire-cycle hypothesis. However, both hypotheses are potentially group selectionist, and resolution of dispersal distances and/or the spatial genetics of relatedness are required to resolve the problem.