1,743 research outputs found

    Land, Income, Mobility and Housing: The Case of Metro Manila

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    Housing developments have been hampered by exorbitantly priced land specifically in the cities. The 1991 housing survey show that Metro Manila households pay the same rate as other households from developing countries. This article reviews the Philippine urban policies and examines the expenditures of owners and renters on shelters. It also investigates the factors on residential mobility among the sample households.urban management, tariff structure, housing program, land management, rent and fee

    Kin Discrimination in Dictyostelium Social Amoebae

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    Presentation delivered at the symposium Evidence of Taxa, Clone, and Kin Discrimination in Protists: Ecological and Evolutionary Implications, VII European Congress of Protistology, University of Seville, 5–10 September 2015, Seville Spain. Evolved cooperation is stable only when the benefactor is compensated, either directly or through its relatives. Social amoebae cooperate by forming a mobile multicellular body in which, about 20% of participants ultimately die to form a stalk. This benefits the remaining individuals that become hardy spores at the top of the stalk, together making up the fruiting body. In studied species with stalked migration, P. violaceum, D. purpureum, and D. giganteum, sorting based on clone identity occurs in laboratory mixes, maintaining high relatedness within the fruiting bodies. D. discoideum has unstalked migration, where cell fate is not fixed until the slug forms a fruiting body. Laboratory mixes show some degree of both spatial and genotype-based sorting, yet most laboratory fruiting bodies remain chimeric. However, wild fruiting bodies are made up mostly of clonemates. A genetic mechanism for sorting is likely to be cell adhesion genes tgrB1 and tgrC1, which bind to each other. They are highly variable, as expected for a kin discrimination gene. It is a puzzle that these genes do not cause stronger discrimination between mixed wild clones, but laboratory conditions or strong sorting early in the social stage diminished by later slug fusion could be explanations

    The distribution of Great Lakes shore plants around inland lakes.

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    http://deepblue.lib.umich.edu/bitstream/2027.42/52667/1/1100.pd

    Ancient bacteria–amoeba relationships and pathogenic animal bacteria

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    Long before bacteria infected humans, they infected amoebas, which remain a potentially important reservoir for human disease. Diverse soil amoebas including Dictyostelium and Acanthamoeba can host intracellular bacteria. Though the internal environment of free-living amoebas is similar in many ways to that of mammalian macrophages, they differ in a number of important ways, including temperature. A new study in PLOS Biology by Taylor-Mulneix et al. demonstrates that Bordetella bronchiseptica has two different gene suites that are activated depending on whether the bacterium finds itself in a hot mammalian or cool amoeba host environment. This study specifically shows that B. bronchiseptica not only inhabits amoebas but can persist and multiply through the social stage of an amoeba host, Dictyostelium discoideum

    Privatization and Property in Biology

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    Organisms evolve to control, preserve, protect and invest in their own bodies. When they do likewise with external resources they privatize those resources and convert them into their own property. Property is a neglected topic in biology, although examples include territories, domiciles and nest structures, food caching, mate guarding, and the resources and partners in mutualisms. Property is important because it represents a solution to the tragedy of the commons; to the extent that an individual exerts long-term control of its property, it can use it prudently, and even invest in it. Resources most worth privatizing are often high in value. To be useful to their owner in the future, they are typically durable and defensible. This may explain why property is relatively rare in animals compared to humans. The lack of institutional property rights in animals also contributes to their rarity, although owner–intruder conventions may represent a simple form of property rights. Resources are often privatized by force or threat of force, but privatization can also be achieved by hiding, by constructing barriers, and by carrying or incorporating the property. Social organisms often have property for two reasons. First, the returns on savings and investments can accrue to relatives, including descendants. Second, social groups can divide tasks among members, so they can simultaneously guard property and forage, for example. Privatization enhances the likelihood that the benefits of cooperation will go to relatives, thus facilitating the evolution of cooperation as in Hamilton\u27s rule or kin selection. Mutualisms often involve exchange of property and privatization of relationships. Privatization ensures the stability of such cooperation. The major transitions in evolution, both fraternal and egalitarian, generally involve the formation of private clubs with something analogous to the nonrivalrous club goods of economics
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