Genomic analysis on pygmy hog reveals extensive interbreeding during wild boar expansion

Wild boar (Sus scrofa) drastically colonized mainland Eurasia and North Africa, most likely from East Asia during the Plio-Pleistocene (2–1Mya). In recent studies, based on genome-wide information, it was hypothesized that wild boar did not replace the species it encountered, but instead exchanged genetic materials with them through admixture. The highly endangered pygmy hog (Porcula salvania) is the only suid species in mainland Eurasia known to have outlived this expansion, and therefore provides a unique opportunity to test this hybridization hypothesis. Analyses of pygmy hog genomes indicate that despite large phylogenetic divergence (~2 My), wild boar and pygmy hog did indeed interbreed as the former expanded across Eurasia. In addition, we also assess the taxonomic placement of the donor of another introgression, pertaining to a now-extinct species with a deep phylogenetic placement in the Suidae tree. Altogether, our analyses indicate that the rapid spread of wild boar was facilitated by inter-specific/inter-generic admixtures.</p

Critical review of the standards of public open spaces for recreation in urban areas of Sri Lanka

A dissertation submitted to the Dept. of Town & Country Planning for the MSc in Town & Country PlanningPublic open space is a vital component of the urban environment which is under increasing pressure due to urban development. It is an essential part of the urban heritage and infrastructure. It not only provides a pleasant and natural environment but also improves the quality of life in urban areas by performing essential environmental functions. Potential economic benefits also accrue by increasing the attractiveness of a place to live and work. In 1990 Urban Development Authority formulated a standard of "1 ha of public open space per 1000people" to provide adequate amount of public open space in urban areas. This standard has been introduced mainly focusing on the urban development pattern of Colombo City. Although the prepared development plans for Colombo City had envisaged to provide sufficient amount of public open spaces, it was still not become a fruitful effort due to various reasons. It can be seen that people use the available public open spaces without seeking more spaces.Although the standard cannot reach the extent of public open space which the urban area actually needs, a direct demand for more spaces of urban people is not visible .Therefore, it appears that the lack of public open spaces has not been felt considering the life pattern of the urban dwellers. But the perception of urban people on public open spaces differs from what can be ~seen on the surface. Because of that, the objective of this study is to review the existing situation in regard to public open spaces in urban areas according to the standard. The study is mainly based on the public perception of the urban people. Although there are several studies on public open spaces relating to urban designing and urban planning aspects, there have been no studies done on urban public open space standards. Therefore this study will add new knowledge to the field of urban designing and urban planning. The evaluation of this study enables to identify the existing situation of the public open spaces in urban areas in terms of the currant standard light of public perception and it was help to review the current urban public open spaces standard of "1 ha of land per 1 000 people". The standard is reviewed through its application upon Mattakkuliya Ward of the Colombo Municipal Council area, which is the selected urban development area for the purpose

CHOICE OF A REFERENCE STATE FOR EXERGETIC ANALYSIS

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Exergetic evaluation of a cogeneration system in a petrochemical complex

The purpose of this paper is the study of a real cogeneration system existing in a petrochemical complex. The total capacity of the plant is 200 MW of electrical power and 2100 t/h of steam for processes. This work presents the mass and energy balances of this cogeneration system. Exergy of each involved stream is calculated and the exergetic balance of each subsystem is presented, as well as of the global system, identifying where and why losses and irreversibility occur. Efficiencies based on the second law of thermodynamics are calculated for each subsystem and compared. Some conclusions regarding operational strategiesare presented. (C) 1998 Elsevier Science Ltd. All rights reserved.3916-181845185