10,459 research outputs found
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Development of allergy in children. I. Association with virus infections.
Children born into allergic families, with two allergic parents, are at high risk of developing allergy within the first 5 years of life. In order to observe possible external factors in the sensitization process, a prospective study of 13 such children was done, in which serial clinical and immunologic observations were made at 3- to 6-month intervals over a period of 1 to 4 yr. Eleven of these children are now clinically allergic; 5 have asthma. Immunologic evidence for allergic sensitization was observed in these 11 children by RAST, antigen-induced leukocyte histamine release, lymphoblastogenesis, and rise in serum IgE. Upper respiratory infections (URI) occurred in these 11 allergic children 1 to 2 months prior to the onset of allergic sensitization. In 10 of these 11 URI children, complement-fixing antibodies to viruses (parainfluenza, RSV, CMV) increased in the same blood samples in which immunologic allergic sensitization was first evidenced. This coincidence suggests that certain viruses may contribute to the allergic sensitization process
A Constraint Programming Approach for Non-Preemptive Evacuation Scheduling
Large-scale controlled evacuations require emergency services to select
evacuation routes, decide departure times, and mobilize resources to issue
orders, all under strict time constraints. Existing algorithms almost always
allow for preemptive evacuation schedules, which are less desirable in
practice. This paper proposes, for the first time, a constraint-based
scheduling model that optimizes the evacuation flow rate (number of vehicles
sent at regular time intervals) and evacuation phasing of widely populated
areas, while ensuring a nonpreemptive evacuation for each residential zone. Two
optimization objectives are considered: (1) to maximize the number of evacuees
reaching safety and (2) to minimize the overall duration of the evacuation.
Preliminary results on a set of real-world instances show that the approach can
produce, within a few seconds, a non-preemptive evacuation schedule which is
either optimal or at most 6% away of the optimal preemptive solution.Comment: Submitted to the 21st International Conference on Principles and
Practice of Constraint Programming (CP 2015). 15 pages + 1 reference pag
Efficiency and persistence in models of adaptation
A cut-and-paste model which mimics a trial-and-error process of adaptation is
introduced and solved. The model, which can be thought of as a diffusion
process with memory, is characterized by two properties, efficiency and
persistence. We establish a link between these properties and determine two
transitions for each property, a percolation transition and a depinning
transition. If the adaptation process is iterated, the antipersistent state
becomes an attractor of the dynamics. Extensions to higher dimensions are
briefly discussed.Comment: 4 pages, 4 figures, submitted to publicatio
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Comprehensive sequence-to-function mapping of cofactor-dependent RNA catalysis in the glmS ribozyme.
Massively parallel, quantitative measurements of biomolecular activity across sequence space can greatly expand our understanding of RNA sequence-function relationships. We report the development of an RNA-array assay to perform such measurements and its application to a model RNA: the core glmS ribozyme riboswitch, which performs a ligand-dependent self-cleavage reaction. We measure the cleavage rates for all possible single and double mutants of this ribozyme across a series of ligand concentrations, determining kcat and KM values for active variants. These systematic measurements suggest that evolutionary conservation in the consensus sequence is driven by maintenance of the cleavage rate. Analysis of double-mutant rates and associated mutational interactions produces a structural and functional mapping of the ribozyme sequence, revealing the catalytic consequences of specific tertiary interactions, and allowing us to infer structural rearrangements that permit certain sequence variants to maintain activity
Nigeria and development in the 21st century: The theatre for development alternative
Indices of development begin with the development of human beings; human beings that will later develop other facets of the society such as the economy, natural, mineral and all other resources available in the country. Hence education is of paramount importance in any nation. The globalization of nations in the close of the 21st century further attests to this reality. It is however sad that while the 'so called developed countries' of the West are fast accelerating in terms of development, the same cannot be said about majority of the 'Third World Countries'. What then are the problems facing such an oil-rich country as Nigeria that has remained practically stagnant in the face of development? This paper therefore seeks to explore some of the reasons for the backwardness and the near stagnation of the country 51years after attaining political independence. The paper argues that the Top-bottom developmental policies rather than the Bottom-top policies are largely responsible for this. We conclude that using the Theatre-for -Development alternative which encompasses the traditional nuances of communication; to conscientize, promote dialogue, conduct research and encourage participation and awareness, sustainable development would be attained
Nigeria and development in the 21st century: The theatre for development alternative
Indices of development begin with the development of human beings; human beings that will later develop other facets of the society such as the economy, natural, mineral and all other resources available in the country. Hence education is of paramount importance in any nation. The globalization of nations in the close of the 21st century further attests to this reality. It is however sad that while the 'so called developed countries' of the West are fast accelerating in terms of development, the same cannot be said about majority of the 'Third World Countries'. What then are the problems facing such an oil-rich country as Nigeria that has remained practically stagnant in the face of development? This paper therefore seeks to explore some of the reasons for the backwardness and the near stagnation of the country 51years after attaining political independence.The paper argues that the Top-bottom developmental policies rather than the Bottom-top policies are largely responsible for this. We conclude that using the Theatre-for -Development alternative which encompasses the traditional nuances of communication; to conscientize, promote dialogue, conduct research and encourage participation and awareness, sustainable development would be attained
Emission spectrum of hot HDO in the 380-2190 cm(-1) region
Fourier transform emission spectra were recorded using a mixture of H2O and D2O at a temperature of 1500 degreesC. The spectra were recorded in three overlapping sections and cover the wavenumber range 380-2190 cm(-1). A total of 22106 lines were measured, of which 60% are thought to belong to HDO. A total of 6430 FIDO transition,, are assigned, including the first transitions to the (040) vibrational state, with a term value of 5420.042 cm(-1). A total of 1536 new energy levels of HDO belonging to the (000), (010) (020), (030), and (040) stated are presented, significantly extending the degree of rotational excitation compared to previous studies. (C) 2001 Elsevier Science
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