Web 2.0, new literacies, and the idea of learning through participation

In this paper I identify some current elaborations on the theme of participation and digital literacy in order to open further debate on the relationship between interaction, collaboration, and learning in online environments. Motivated by an interest in using new technologies in the context of formal learning (Merchant, 2009), I draw on in-school and out-of-school work in Web 2.0 spaces. This work is inflected by the new literacies approach (Lankshear and Knobel, 2006a), and here I provide an overview of the ways in which learning through participation is characterised by those adopting this and other related perspectives. I include a critical examination of the idea of ‘participatory’ culture as articulated in the field of media studies, focusing particularly on the influential work of Jenkins (2006a; 2006b). In order to draw these threads together around conceptualizations of learning, I summarise ways in which participation is described in the literature on socially-situated cognition. This is used to generate some tentative suggestions about how learning and literacy in Web 2.0 spaces might be envisioned and how ideas about participation might inform curriculum planning and design

Systematic errors in global air-sea CO2 flux caused by temporal averaging of sea-level pressure

International audienceLong-term temporal averaging of meteorological data, such as wind speed and air pressure, can cause large errors in air-sea carbon flux estimates. Other researchers have already shown that time averaging of wind speed data creates large errors in flux due to the non-linear dependence of the gas transfer velocity on wind speed (Bates and Merlivat, 2001). However, in general, wind speed is negatively correlated with air pressure, and a given fractional change in the pressure of dry air produces an equivalent fractional change in the atmospheric partial pressure of carbon dioxide (<i>p</i>CO_2air). Thus low pressure systems cause a drop in <i>p</i>CO_2air, which together with the associated high winds, promotes outgassing/reduces uptake of CO₂ from the ocean. Here we quantify the errors in global carbon flux estimates caused by using monthly or climatological pressure data to calculate <i>p</i>CO_2air (and thus ignoring the covariance of wind and pressure) over the period 1990?1999, using two common parameterisations for gas transfer velocity (Wanninkhof, 1992 (W92) and Wanninkhof and McGillis, 1999 (WM99)). Results show that on average, compared with estimates made using 6 hourly pressure data, the global oceanic sink is systematically overestimated by 7% (W92) and 10% (WM99) when monthly mean pressure is used, and 9% (W92) and 12% (WM99) when climatological pressure is used

The use of high altitude aerial photography to inventory wildlife habitat in Kansas: An initial evaluation

The use of aerial photography as a method for determining the wildlife conditions of an area is discussed. Color infrared photography is investigated as the most effective type of remote sensor. The characteristics of the remote sensing systems are described. Examples of the remote sensing operation and the method for reducing the data are presented

Methods for Combining Payload Parameter Variations with Input Environment

Methods are presented for calculating design limit loads compatible with probabilistic structural design criteria. The approach is based on the concept that the desired limit load, defined as the largest load occuring in a mission, is a random variable having a specific probability distribution which may be determined from extreme-value theory. The design limit load, defined as a particular value of this random limit load, is the value conventionally used in structural design. Methods are presented for determining the limit load probability distributions from both time-domain and frequency-domain dynamic load simulations. Numerical demonstrations of the methods are also presented

Effect of damping on excitability of high-order normal modes

The effect of localized structural damping on the excitability of higher-order large space telescope spacecraft modes is investigated. A preprocessor computer program is developed to incorporate Voigt structural joint damping models in a finite-element dynamic model. A postprocessor computer program is developed to select critical modes for low-frequency attitude control problems and for higher-frequency fine-stabilization problems. The selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensor, and on image-plane motions due to sinusoidal or random PSD force and torque inputs

An Autoignition Study of iso-Butanol: Experiments and Modeling

The autoignition delays of iso-butanol, oxygen, and nitrogen mixtures have been measured in a heated rapid compression machine (RCM). At compressed pressures of 15 and 30 bar, over the temperature range 800-950 K, and for equivalence ratio of $\phi$ = 0.5 in air, no evidence of an NTC region of overall ignition delay is found. By comparing the data from this study taken at $\phi$ = 0.5 to previous data collected at $\phi$ = 1.0 (Weber et al. 2013), it was found that the $\phi$ = 0.5 mixture was less reactive (as measured by the inverse of the ignition delay) than the $\phi$ = 1.0 mixture for the same compressed pressure. Furthermore, a recent chemical kinetic model of iso-butanol combustion was updated using the automated software Reaction Mechanism Generator (RMG) to include low- temperature chain branching pathways. Comparison of the ignition delays with the updated model showed reasonable agreement for most of the experimental conditions. Nevertheless, further work is needed to fully understand the low temperature pathways that control iso-butanol autoignition in the RCM.Comment: 6 pages, 4 figures, 8th US National Combustion Meetin

The effects of localized damping on structural response

The effect of localized structural damping on the excitability of higher order normal modes of the large space telescope was investigated. A preprocessor computer program was developed to incorporate Voigt structural joint damping models in a NASTRAN finite-element dynamic model. A postprocessor computer program was developed to select critical modes for low-frequency attitude control problems and for higher frequency fine-stabilization problems. The mode selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensors, and on image-plane motions due to sinusoidal or random power spectral density force and torque inputs

Methods for combining payload parameter variations with input environment

Methods are presented for calculating design limit loads compatible with probabilistic structural design criteria. The approach is based on the concept that the desired limit load, defined as the largest load occurring in a mission, is a random variable having a specific probability distribution which may be determined from extreme-value theory. The design limit load, defined as a particular of this random limit load, is the value conventionally used in structural design. Methods are presented for determining the limit load probability distributions from both time-domain and frequency-domain dynamic load simulations. Numerical demonstrations of the method are also presented

Mode superposition in multi-degree of freedom systems using earthquake response spectrum data

Dynamic responses of a series of typical three-degree of freedom structures to strong-motion earthquake excitation were calculated by analog computer techniques and were compared with approximate responses obtained by a superposition of individual modes derived from response spectrum curves. The results indicate that a suitably weighted average of the sum of the absolute values of the individual modes and the square root of the sum of the squares of the modes will give a practical design criterion for the base shear forces in multi-story buildings. For critical designs, this weighted average reduces to the absolute sum of the modes, which is found to be close to the true value for a significantly high proportion of typical earthquake-structure combinations