1,878 research outputs found

    Results from the EPL monkey-pod flight experiments conducted aboard the NASA/Ames CV-990, May 1976

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    The participation of the Environmental Physiology Laboratory (EPL) in the general purpose laboratory concept verification test 3 is documented. The EPL Monkey-Pod Experiment was designed to incorporate a 10-12 kg, pig tailed monkey, Macaca nemestrina, into the pod and measure the physiological responses of the animal continously. Four major elements comprise the EPL Monkey-Pod Experiment System: (1) a fiberglass pod containing the instrumented monkey plus feeder and watering devices, (2) an inner console containing the SKYLAB mass spectrometer with its associated valving and electronic controls, sensing, control and monitoring units for lower body negative pressure, feeder activity, waterer activity, temperatures, and gas metabolism calibration, (3) an umbilical complex comprising gas flow lines and electrical cabling between the inner and outer console and (4) an outer console in principle representing the experiment support to be provided from general space craft sources

    Reliability and Validity of Widely Used International Surveys on the Environment

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    Do existing public opinion surveys provide valid and reliable measures of attitudes towards environmental sustainability? This question is critical given the importance of public support for achieving sustainability. Starting with 28 survey items about the environment drawn from the World Values Survey Waves 5 and 6 and the 2010 International Social Survey Program, we assessed reliability by checking for significant correlations between similar or identical items on different surveys. Next, to assess validity, we evaluated correlations between survey items and 22 objective environmental indicators drawn from the Environmental Performance Index (EPI). As the level of economic development is a likely confound, we also performed partial correlation analyses controlling for GDP per capita. From the initial 28 items, we identified 23 sufficiently reliable items, but many of these were found to have low predictive power in the validity analysis. Items about air and water pollution were valid predictors of objective environmental conditions in these areas. Items asking about the relative importance of environmental problems compared to other social issues were also good positive predictors of progress on perceptible environmental issues. Items asking about general sentiment with no clear referent performed poorly. When controlling for GDP, country-level attitudes were more aligned with country-specific environmental conditions. Finally, nearly half of all EPI indicators were associated with few or no survey items, indicating the existence of 'blind spots' in public awareness. Our findings should offer guidance to both survey developers and users, as well as to policy makers responsible for conveying information about environmental sustainability to the wider public

    Parallel distributed algorithms of the beta-model of the small world graphs

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    The research goal is to develop a large-scale agent-based simulation environment to support implementations of Internet simulation applications.The Small Worlds (SW) graphs are used to model Web sites and social networks of Internet users. Each vertex represents the identity of a simple agent. In order to cope with scalability issues, we have to consider distributed parallel processing. The focus of this paper is to present two parallel-distributed algorithms for the construction of a particular type of SW graph called Beta-model. The first algorithm serializes the graph construction, while the second constructs the graph in parallel

    Statistical algorithms for a comprehensive test ban treaty discrimination framework

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    Reasoning on transition from manipulative strategies to general procedures in solving counting problems

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    We describe the procedures used by 11- to 12-year-old students for solving basic counting problems in order to analyse the transition from manipulative strategies involving direct counting to the use of the multiplication principle as a general procedure in combinatorial problems. In this transition, the students sometimes spontaneously use tree diagrams and sometimes use numerical thinking strategies. We relate the findings of our research to recent research on the representational formats on the learning of combinatorics, and reflect on the didactic implications of these investigations

    Charge fluctuations close to phase separation in the two dimensional t-J model

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    We have studied the t-J model using the Green Function Monte Carlo technique. We have obtained accurate energies well converged in the thermodynamic limit, by performing simulations up to 242 lattice sites. By studying the energy as a function of hole doping we conclude that there is no phase separation in the physical region, relevant for HTc superconductors. This finding is further supported by the hole-hole correlation function calculation. Remarkably, by approaching the phase separation instability, for Jc/t0.5J_c/t\sim 0.5,this function displays enhanced fluctuations at incommensurate wavevectors, scaling linearly with the doping, in agreement with experimental findings.Comment: To appear on Phys. Rev. Let

    Graphical representation and generalization in sequences problems

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    In this paper we present different ways used by Secondary students to generalize when they try to solve problems involving sequences. 359 Spanish students solved generalization problems in a written test. These problems were posed through particular terms expressed in different representations. We present examples that illustrate different ways of achieving various types of generalization and how students express generalization. We identify graphical representation of generalization as a useful tool of getting other ways of expressing generalization, and we analyze its connection with other ways of expressing it

    Optimization for Sustainable Design through Building Information Modeling

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    More than thirty years after the definition of the concept of sustainable development, the European Union's Agenda 2030 renews its commitment to protect the Planet and to support the needs of present and future generations. All sectors of human activity have to make their contribution to this significant challenge of our time. Therefore, the construction sector can also make an essential contribution in terms of its impact. In this context, designers are called upon to modify their actions in order to take into account the environmental, social, and economic impacts during the entire life cycle of construction. Therefore, a substantial transformation in the designer's "mentality" is necessary. The digital revolution could be a suitable opportunity for a profound renewal oriented towards sustainability. The new digital technologies and the increased computing power are useful to manage the increasing complexity in current projects and to support collaboration between the many experts involved. The thesis aim is to analyse the current state and identify the signs of change and the cues to imagine possible virtuous complicity between sustainable development goals and the potential of the digital revolution, supported by the operational features of optimization methods. The further intent is to translate the synergy between the three key topics - sustainability, digitization, and optimization - through an operational strategy that can be a concrete demonstration of what is proposed and offered to designers
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