41,787 research outputs found
What Can Be Learned from Computer Modeling? Comparing Expository and Modeling Approaches to Teaching Dynamic Systems Behavior
Computer modeling has been widely promoted as a means to attain higher order learning outcomes. Substantiating these benefits, however, has been problematic due to a lack of proper assessment tools. In this study, we compared computer modeling with expository instruction, using a tailored assessment designed to reveal the benefits of either mode of instruction. The assessment addresses proficiency in declarative knowledge, application, construction, and evaluation. The subscales differentiate between simple and complex structure. The learning task concerns the dynamics of global warming. We found that, for complex tasks, the modeling group outperformed the expository group on declarative knowledge and on evaluating complex models and data. No differences were found with regard to the application of knowledge or the creation of models. These results confirmed that modeling and direct instruction lead to qualitatively different learning outcomes, and that these two modes of instruction cannot be compared on a single “effectiveness measure”
Mathematics for Non-Science Majors Chemistry Course
A chemistry course developed for non-science majors has been taught at Virginia Commonwealth University for the past five years. CHEM 112 uses current event articles from science magazines to make use of a verbal channel of learning in non-science majors, but some mathematics is necessary. Examples are given of successful presentation of nuclear chemistry and data needed for a balanced discussion of global warming. Manipulation of symbols in balancing chemical and nuclear reactions, simple algebra, and logarithms for pH and unit analysis of simple stoichiometric conversions are fundamental to basic chemistry. The population of a voting democracy could benefit from basic education in the concepts of logarithms and algebra in one variable in order to function in a society of increasing dependence on technology
Climate Change Research in View of Bibliometrics
This bibliometric study of a large publication set dealing with research on
climate change aims at mapping the relevant literature from a bibliometric
perspective and presents a multitude of quantitative data: (1) The growth of
the overall publication output as well as (2) of some major subfields, (3) the
contributing journals and countries as well as their citation impact, and (4) a
title word analysis aiming to illustrate the time evolution and relative
importance of specific research topics. The study is based on 222,060 papers
published between 1980 and 2014. The total number of papers shows a strong
increase with a doubling every 5-6 years. Continental biomass related research
is the major subfield, closely followed by climate modeling. Research dealing
with adaptation, mitigation, risks, and vulnerability of global warming is
comparatively small, but their share of papers increased exponentially since
2005. Research on vulnerability and on adaptation published the largest
proportion of very important papers. Research on climate change is
quantitatively dominated by the USA, followed by the UK, Germany, and Canada.
The citation-based indicators exhibit consistently that the UK has produced the
largest proportion of high impact papers compared to the other countries
(having published more than 10,000 papers). The title word analysis shows that
the term climate change comes forward with time. Furthermore, the term impact
arises and points to research dealing with the various effects of climate
change. Finally, the term model and related terms prominently appear
independent of time, indicating the high relevance of climate modeling.Comment: 40 pages, 6 figures, and 4 table
Local Warming
Using 55 years of daily average temperatures from a local weather station, I
made a least-absolute-deviations (LAD) regression model that accounts for three
effects: seasonal variations, the 11-year solar cycle, and a linear trend. The
model was formulated as a linear programming problem and solved using widely
available optimization software. The solution indicates that temperatures have
gone up by about 2 degrees Fahrenheit over the 55 years covered by the data. It
also correctly identifies the known phase of the solar cycle; i.e., the date of
the last solar minimum. It turns out that the maximum slope of the solar cycle
sinusoid in the regression model is about the same size as the slope produced
by the linear trend. The fact that the solar cycle was correctly extracted by
the model is a strong indicator that effects of this size, in particular the
slope of the linear trend, can be accurately determined from the 55 years of
data analyzed.
The main purpose for doing this analysis is to demonstrate that it is easy to
find and analyze archived temperature data for oneself. In particular, this
problem makes a good class project for upper-level undergraduate courses in
optimization or in statistics.
It is worth noting that a similar least-squares model failed to characterize
the solar cycle correctly and hence even though it too indicates that
temperatures have been rising locally, one can be less confident in this
result.
The paper ends with a section presenting similar results from a few thousand
sites distributed world-wide, some results from a modification of the model
that includes both temperature and humidity, as well as a number of suggestions
for future work and/or ideas for enhancements that could be used as classroom
projects.Comment: 12 pages, 5 figures, to appear in SIAM Revie
Transportation Life Cycle Assessment Synthesis: Life Cycle Assessment Learning Module Series
The Life Cycle Assessment Learning Module Series is a set of narrated, self-advancing slideshows on various topics related to environmental life cycle assessment (LCA). This research project produced the first 27 of such modules, which are freely available for download on the CESTiCC website http://cem.uaf.edu/cesticc/publications/lca.aspx. Each module is roughly 15- 20 minutes in length and is intended for various uses such as course components, as the main lecture material in a dedicated LCA course, or for independent learning in support of research projects. The series is organized into four overall topical areas, each of which contain a group of overview modules and a group of detailed modules. The A and α groups cover the international standards that define LCA. The B and β groups focus on environmental impact categories. The G and γ groups identify software tools for LCA and provide some tutorials for their use. The T and τ groups introduce topics of interest in the field of transportation LCA. This includes overviews of how LCA is frequently applied in that sector, literature reviews, specific considerations, and software tutorials. Future modules in this category will feature methodological developments and case studies specific to the transportation sector
Sensitivity of Climate Change Projections to Uncertainties in the Estimates of Observed Changes in Deep-Ocean Heat Content
Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).The MIT 2D climate model is used to make probabilistic projections for changes in global mean surface temperature and for thermosteric sea level rise under a variety of forcing scenarios. The uncertainties in climate sensitivity and rate of heat uptake by the deep ocean are quantified by using the probability distributions derived from observed 20th century temperature changes. The impact on climate change projections of using the smallest and largest estimates of 20th century deep ocean warming is explored. The impact is large in the case of global mean thermosteric sea level rise. In the MIT reference ("business as usual") scenario the median rise by 2100 is 27 and 43 cm in the respective cases. The impact on increases in global mean surface air temperature is more modest, 4.9 C and 3.9 C in the two respective cases, because of the correlation between climate sensitivity and ocean heat uptake required by 20th century surface and upper air temperature changes. The results are also compared with the projections made by the IPCC AR4's multi-model ensemble for several of the SRES scenarios. The multi-model projections are more consistent with the MIT projections based on the largest estimate of ocean warming. However the range for the rate of heat uptake by the ocean suggested by the lowest estimate of ocean warming is more consistent with the range suggested by the 20th century changes in surface and upper air temperatures, combined with expert prior for climate sensitivity.This work was supported in part by the Office of Science (BER), U.S. Dept. of Energy Grant No. DE-FG02-93ER61677, NSF, and by the MIT Joint Program on the Science and Policy of Global Change
Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics
The atmospheric greenhouse effect, an idea that many authors trace back to
the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896),
and which is still supported in global climatology, essentially describes a
fictitious mechanism, in which a planetary atmosphere acts as a heat pump
driven by an environment that is radiatively interacting with but radiatively
equilibrated to the atmospheric system. According to the second law of
thermodynamics such a planetary machine can never exist. Nevertheless, in
almost all texts of global climatology and in a widespread secondary literature
it is taken for granted that such mechanism is real and stands on a firm
scientific foundation. In this paper the popular conjecture is analyzed and the
underlying physical principles are clarified. By showing that (a) there are no
common physical laws between the warming phenomenon in glass houses and the
fictitious atmospheric greenhouse effects, (b) there are no calculations to
determine an average surface temperature of a planet, (c) the frequently
mentioned difference of 33 degrees Celsius is a meaningless number calculated
wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the
assumption of a radiative balance is unphysical, (f) thermal conductivity and
friction must not be set to zero, the atmospheric greenhouse conjecture is
falsified.Comment: 115 pages, 32 figures, 13 tables (some typos corrected
Event program
UNLV Undergraduates from all departments, programs and colleges participated in a campus-wide symposium on April 16, 2011. Undergraduate posters from all disciplines and also oral presentations of research activities, readings and other creative endeavors were exhibited throughout the festival
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