80 research outputs found
Review of the Book - Teaching about Technology: An Introduction to the Philosophy of Technology for Non-Philosophers
Marc de Vries\u27 latest book, Teaching about Technology: An Introduction to the Philosophy of Technology for Non-Philosophers, was interesting to the reviewer because it provided a link between philosophies of technology and the nature of the technology curriculum more than any other philosophy-related work he has read. The book is intended for use with pre-service teachers, graduate students, and others who are interested in teaching technology. Teaching about Technology is part of a series of books on science and technology that is edited by William Cobern of Western Michigan University in Kalamazoo, Michigan. The editorial board for the series is comprised of university professors from around the world including Ghana, South Africa, Columbia, Hong Kong, and Taiwan. The series, entitled Science and Technology Education Library, is primarily related to science education. The publisher, Springer, is based in Berlin, Germany but has a number of publication outlets around the world and is involved in science and technology related publications generally
Engineering Student Outcomes for Grades 9-12
The following research study was conducted during the 2005 – 2006 academic year. Its purpose is to help the National Center for Engineering and Technology Education determine those engineering outcomes that should be studied in high school when the high school student intends to pursue engineering in college. The results of the study will also be used to determine those engineering student outcomes that all technology education high school students should learn in order to aid them in becoming more technologically literate.
A modified Delphi approach as used for the study. The participants were a panel of experts consisting of engineers, engineering educators, or those expertly familiar with engineering education such as a government expert or learned society employee. The modified Delphi study ran for six rounds of inquiry during which the panel of experts reached consensus on the identity and importance of 43 engineering student outcomes for use in pre-engineering high school student learning. The panel of experts also reached consensus on the relative importance of three of seven groupings of engineer student outcomes for high school
Logic Circuits and the Quality of Life
The article presents information on the relationship between the logic circuits and the quality of life. The applications of logic circuits are countless. With the flooding of New Orleans in the wake of Hurricane Katrina, people around the world became all too aware of human dependency on technology to manage the forces of nature and maintain a high quality of life. New Orleans\u27 sewage and water control systems depend on water pumps to move sewage, storm-water runoff, and fresh water around the city. Under normal conditions, when it rains in New Orleans, a city that sits below sea level, massive water pumps are automatically engaged, and ram water is pumped into Lake Pontchartrain, a nearby reservoir. However, when Katrina hit and electrical power to the city was cut, the system failed. The transport of drinking water is one of the technological marvels that people do not think about until they have to go without. At the heart of the system that automates water pumping is an electronic control circuit. Electronic control circuits are used in a wide variety of applications, from controlling pump motors to making automobiles more safe and efficient. Apart from this, logic circuits are used in temperature control units, security systems, and arithmetic circuits for a variety of microprocessors built into everything from computers to microwave ovens
On quasianalytic local rings
This expository article is devoted to the local theory of ultradifferentiable
classes of functions, with a special emphasis on the quasianalytic case.
Although quasianalytic classes are well-known in harmonic analysis since
several decades, their study from the viewpoint of differential analysis and
analytic geometry has begun much more recently and, to some extent, has earned
them a new interest. Therefore, we focus on contemporary questions closely
related to topics in local algebra. We study, in particular, Weierstrass
division problems and the role of hyperbolicity, together with properties of
ideals of quasianalytic germs. Incidentally, we also present a simplified proof
of Carleman's theorem on the non-surjectivity of the Borel map in the
quasianalytic case.Comment: Final Manuscrip
Particle approximation of the one dimensional Keller-Segel equation, stability and rigidity of the blow-up
We investigate a particle system which is a discrete and deterministic
approximation of the one-dimensional Keller-Segel equation with a logarithmic
potential. The particle system is derived from the gradient flow of the
homogeneous free energy written in Lagrangian coordinates. We focus on the
description of the blow-up of the particle system, namely: the number of
particles involved in the first aggregate, and the limiting profile of the
rescaled system. We exhibit basins of stability for which the number of
particles is critical, and we prove a weak rigidity result concerning the
rescaled dynamics. This work is complemented with a detailed analysis of the
case where only three particles interact
Reproduction and respiration of a climate change indicator species: effect of temperature and variable food in the copepod Centropages chierchiae
The abundance of the calanoid copepod Centropages chierchiae has increased at the northern limits of its distribution in recent decades, mainly due to oceanic climate forcing, suggesting this as a key species in monitoring climate change. Laboratory experiments were conducted to study the combined effect of temperature, food type and concentration on the egg production rate (EPR) and hatching success (HS) of C. chierchiae. Females were fed on two monoalgal diets (Gymnodinium sp. and Phaeodactylum tricornutum) at two food concentrations and at three different temperatures (13, 19, 24C). Respiration rates of both genders were measured at four different temperatures (8, 13, 19, 24C). EPR was significantly different between temperatures and food concentrations, the maximum EPR being attained when the copepods were exposed to high food levels and at 19C. Prey type significantly influenced EPR; feeding on P. tricornutum resulted in higher egg production than Gymnodinium sp. HS was significantly lower at 13C than at 19 and 24C and higher with Gymnodinium sp. Respiration rates were sex independent and increased exponentially with temperature. To maintain basal metabolism, the minimum food intake of P. tricornutum ranged between 0.4 and 1.8 g C and for Gymnodinium sp. between 0.03 and 0.13 g C. Food intake was always higher than the metabolic demands, except for the highest temperature tested (24C). The present results confirm the sensitivity of C. chierchiae to temperature variations and may help in understanding the successful expansion of its distribution towards northern latitudes.Portuguese Science and Technology Foundation (FCT) [PTDC/MAR/098643/2008, PTDC/MAR/111304/2009, PTDC/MAR/0908066/2008]; FCT [SFRH/BD/28198/2006]; [SFRH/BPD/38332/2007
Localized bioconvection of Euglena caused by phototaxis in the lateral direction
Euglena, a swimming micro-organism, exhibited a characteristic bioconvection
that was localized at the center of a sealed chamber under bright illumination
to induce negative phototaxis. This localized pattern consisted of high-density
spots, in which convection was found. These observations were reproduced by a
mathematical model that was based on the phototaxis of individual cells in both
the vertical and lateral directions. Our results indicate that this convection
is maintained by upward swimming, as with general bioconvection, and the
localization originates from lateral phototaxis
The Sediment Green-Blue Color Ratio as a Proxy for Biogenic Silica Productivity Along the Chilean Margin
Sediment cores recently collected from the Chilean Margin during D/V JOIDES Resolution Expedition 379T (JR100) document variability in shipboard-generated records of the green/blue (G/B) ratio. These changes show a strong coherence with benthic foraminiferal δ18O, Antarctic ice core records, and sediment lithology (e.g., higher diatom abundances in greener sediment intervals), suggesting a climate-related control on the G/B. Here, we test the utility of G/B as a proxy for diatom productivity at Sites J1002 and J1007 by calibrating G/B to measured biogenic opal. Strong exponential correlations between measured opal% and the G/B were found at both sites. We use the empirical regressions to generate high-resolution records of opal contents (opal%) on the Chilean Margin. Higher productivity tends to result in more reducing sedimentary conditions. Redox-sensitive sedimentary U/Th generally co-varies with the reconstructed opal% at both sites, supporting the association between sediment color, sedimentary U/Th, and productivity. Lastly, we calculated opal mass accumulation rate (MAR) at Site J1007 over the last ∼150,000 years. The G/B-derived opal MAR record from Site J1007 largely tracks existing records derived from traditional wet-alkaline digestion from the south and eastern equatorial Pacific (EEP) Ocean, with a common opal flux peak at ∼50 ka suggesting that increased diatom productivity in the EEP was likely driven by enhanced nutrient supply from the Southern Ocean rather than dust inputs as previously suggested. Collectively, our results identify the G/B ratio as a useful tool with the potential to generate reliable, high-resolution paleoceanographic records that circumvent the traditionally laborious methodology.publishedVersio
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