2,175 research outputs found

    Ocean warming-acidification synergism undermines dissolved organic matter assembly.

    Get PDF
    Understanding the influence of synergisms on natural processes is a critical step toward determining the full-extent of anthropogenic stressors. As carbon emissions continue unabated, two major stressors--warming and acidification--threaten marine systems on several scales. Here, we report that a moderate temperature increase (from 30°C to 32°C) is sufficient to slow--even hinder--the ability of dissolved organic matter, a major carbon pool, to self-assemble to form marine microgels, which contribute to the particulate organic matter pool. Moreover, acidification lowers the temperature threshold at which we observe our results. These findings carry implications for the marine carbon cycle, as self-assembled marine microgels generate an estimated global seawater budget of ~1016 g C. We used laser scattering spectroscopy to test the influence of temperature and pH on spontaneous marine gel assembly. The results of independent experiments revealed that at a particular point, both pH and temperature block microgel formation (32°C, pH 8.2), and disperse existing gels (35°C). We then tested the hypothesis that temperature and pH have a synergistic influence on marine gel dispersion. We found that the dispersion temperature decreases concurrently with pH: from 32°C at pH 8.2, to 28°C at pH 7.5. If our laboratory observations can be extrapolated to complex marine environments, our results suggest that a warming-acidification synergism can decrease carbon and nutrient fluxes, disturbing marine trophic and trace element cycles, at rates faster than projected

    FFTPL: An Analytic Placement Algorithm Using Fast Fourier Transform for Density Equalization

    Full text link
    We propose a flat nonlinear placement algorithm FFTPL using fast Fourier transform for density equalization. The placement instance is modeled as an electrostatic system with the analogy of density cost to the potential energy. A well-defined Poisson's equation is proposed for gradient and cost computation. Our placer outperforms state-of-the-art placers with better solution quality and efficiency

    Is Contract Farming More Profitable and Efficient Than Non-Contract Farming-A Survey Study of Rice Farms In Taiwan

    Get PDF
    Trade liberalization and globalization has modernized the food retail sector in Taiwan, affecting consumers, producers and trade patterns. These changes have placed significant pressures on farmers and processors including more stringent quality control and product varieties. The government has launched a rice production-marketing contract program in 2005 to assist rice farmers and the agro-business sector to work together as partners. The minimum scale for each contract is 50 hectares of adjacent rice paddies with 50 participants including rice farmers, seedling providers, millers and marketing agents. In order to evaluate the outcome of this program, a survey is conducted in the summer of 2005 after the first (spring) crop is harvested. Information of price and value of output and major variable and fixed inputs are collected along with characteristics of the farmers and farms. The survey results show that the average revenue of a contract farm is about 11 percent higher than an average non-contract farm. The per hectare cost of production in a contract farm is about 13 percent lower and as a result the average profit margin under contract is more than 50 percent above those without contract. A swtiching regression profit frontier model is adopted to further investigate their efficiency performance. The result indicates that an average contract farms is 20 percent more efficient than an average non-contract farm in a comparable operating environment. The result also suggests that although contract farming has potential to improve the profit of smallholders, it is not a sufficient condition for such improvement.Land Economics/Use,

    Towards An Integrated Effort For Managing IT Process Standards Implementation

    Get PDF
    Adopting IT process standards seems to be a trend for IT organizations to meet ad-hoc informational needs and to provide better business value. Due to the changing environments of IT organizations themselves, one key to IT success lies in not only the establishment, but also the sustainability of ad-hoc professional IT functions. As IT organizations face many kinds of process standards to implement for various IT functions and although the implementations may be different due to various IT domains, from the management point of view, these implementations may not exist individually. This article attempts to highlight a possibility of an integrated effort to effectively manage the implementations of IT standards in an IT organization. Such a shared management refers to the integrated institutionalization design, which provides a road map for all IT functions to systematically improve and sustain the implementation results. A case example is provided for demonstrating the proposed attempt

    IT Portfolio Investment Evaluation on E-Commerce Solution Alternatives

    Get PDF
    Our study examines the group decision-making process and proposes a multi-criteria framework for e-commerce solution investment in information technology (IT) portfolios. First, the evaluation criteria that fit in the IT evaluation context are constructed. Second, the Fuzzy Analytic Hierarchy Process (FAHP) is employed to determine the weights of decision criteria and the benefit score to the company. Third, the Fuzzy Multiple Criteria Decision-Making (FMCDM) approach is used to synthesize the team decision. Finally, an empirical case of five proposed portal solutions in a car manufacturing company is used to exemplify the approach
    • …
    corecore