Life’s Lessons in the Lab: A Summer of Learning from Undergraduate Research Experiences

Research experiences for undergraduates (REUs) seek to increase the participating students’ knowledge and perceptions of scientific research through engagement in laboratory research and related activities. Various REU outcomes have been investigated, including influence on participants’ content knowledge, career plans, and general perceptions of their domains of research. The complexity of REUs and dynamic nature of student development provide opportunity for exploring how REUs influence student growth. Our research focused on first and second-year college students who participated in a residential REU program that took place in a chemistry department in a metropolitan university in the western United States. We assessed the standard REU outcomes and sought to document the emotions the students experienced through their participation. In addition, we used the developmental framework of self-authorship (Baxter-Magolda, 2004) as a lens to investigate the participants’ professional identity development. Our mixed methods research revealed shifts in the participants’ perceptions of science, increases in their knowledge of chemistry, and clarity in their career trajectories. We also found that the REU participants experienced profound levels of professional identity growth and used a number of affective terms, such as confidence, persistence, patience, and enjoyment, to describe their experience. Interpretations and implications are discussed

A Comparison of Approaches and Instruments for Evaluating a Geological Sciences Research Experiences Program

This article describes a study in which changes in knowledge of science and attitudes regarding science among participants in a summer Research Experiences for Undergraduates (REU) program were examined. It was discovered that existing survey instruments could not detect changes in participants' attitudes over the course of the program and also failed to detect differences between geoscience faculty and a group of college students with limited exposure to college level science. In response to this, researchers developed a new survey instrument based on clusters of statements representing a variety of philosophical positions, from which respondents must pick one statement. It was discovered that open-ended questions about the nature of science provide a potentially richer source of information and that a survey instrument designed to probe more subtle aspects of one's beliefs about science can be used to assess adults who have had a variety of different kinds of exposure to science. The pilot survey instrument may also be able, with modifications, to assess attitude and knowledge changes caused by participation in a scientific research experience. Educational levels: Graduate or professional

Optimal Output Regulation for Square, Over-Actuated and Under-Actuated Linear Systems

This paper considers two different problems in trajectory tracking control for linear systems. First, if the control is not unique which is most input energy efficient. Second, if exact tracking is infeasible which control performs most accurately. These are typical challenges for over-actuated systems and for under-actuated systems, respectively. We formulate both goals as optimal output regulation problems. Then we contribute two new sets of regulator equations to output regulation theory that provide the desired solutions. A thorough study indicates solvability and uniqueness under weak assumptions. E.g., we can always determine the solution of the classical regulator equations that is most input energy efficient. This is of great value if there are infinitely many solutions. We derive our results by a linear quadratic tracking approach and establish a useful link to output regulation theory.Comment: 8 pages, 0 figures, final version to appear in IEEE Transactions on Automatic Contro

Low-energy neutrino physics and neutrino mass

Among the principal concerns in neutrino physics today are the questions of whether neutrinos are massive and, if so, whether the neutrinos emitted in a weak decay are pure or mixed quantum states. The concept of mixed neutrinos has been with us for more than 20 years, having first been introduced by Maki et al (1) and by Pontecorvo (2) following demonstration in 1962 that more than one type (flavor) of neutrino existed. After having been dormant for some time, the interest in these issues was reborn in recent years with the advent of grand unified theories, which predict nonvanishing neutrino mass and which can accommodate eutrino mixing, in a natural way. Controversial experiments also refueled the excitment (and consternation) of researchers in this endeavor

Taking Risks Behind the Veil of Ignorance

A natural view in distributive ethics is that everyone's interests matter, but the interests of the relatively worse off matter more than the interests of the relatively better off. I provide a new argument for this view. The argument takes as its starting point the proposal, due to Harsanyi and Rawls, that facts about distributive ethics are discerned from individual preferences in the "original position." I draw on recent work in decision theory, along with an intuitive principle about risk-taking, to derive the view

Ellsberg Paradox: Ambiguity And Complexity Aversions Compared

We present a simple model where preferences with complexity aversion, rather than ambiguity aversion, resolve the Ellsberg paradox. We test our theory using laboratory experiments where subjects choose among lotteries that “range” from a simple risky lottery, through risky but more complex lotteries, to one similar to Ellsberg’s ambiguity urn. Our model ranks lotteries according to their complexity and makes different—at times contrasting—predictions than most models of ambiguity in response to manipulations of prizes. The results support that complexity aversion preferences play an important and separate role from beliefs with ambiguity aversion in explaining behavior under uncertainty

A new unsupervised feature selection method for text clustering based on genetic algorithms

Nowadays a vast amount of textual information is collected and stored in various databases around the world, including the Internet as the largest database of all. This rapidly increasing growth of published text means that even the most avid reader cannot hope to keep up with all the reading in a field and consequently the nuggets of insight or new knowledge are at risk of languishing undiscovered in the literature. Text mining offers a solution to this problem by replacing or supplementing the human reader with automatic systems undeterred by the text explosion. It involves analyzing a large collection of documents to discover previously unknown information. Text clustering is one of the most important areas in text mining, which includes text preprocessing, dimension reduction by selecting some terms (features) and finally clustering using selected terms. Feature selection appears to be the most important step in the process. Conventional unsupervised feature selection methods define a measure of the discriminating power of terms to select proper terms from corpus. However up to now the valuation of terms in groups has not been investigated in reported works. In this paper a new and robust unsupervised feature selection approach is proposed that evaluates terms in groups. In addition a new Modified Term Variance measuring method is proposed for evaluating groups of terms. Furthermore a genetic based algorithm is designed and implemented for finding the most valuable groups of terms based on the new measure. These terms then will be utilized to generate the final feature vector for the clustering process . In order to evaluate and justify our approach the proposed method and also a conventional term variance method are implemented and tested using corpus collection Reuters-21578. For a more accurate comparison, methods have been tested on three corpuses and for each corpus clustering task has been done ten times and results are averaged. Results of comparing these two methods are very promising and show that our method produces better average accuracy and F1-measure than the conventional term variance method

A Two-Country NATREX Model for the Euro/Dollar

This paper develops a NATREX (NATural Real EXchange rate) model for two large economies, the Eurozone and the United States. The NATREX approach has already been adopted to explain the medium-long term dynamics of the real exchange rate in a number of industrial countries. So far, however, it has been applied to a one-country framework where the "rest of the world" is treated as given. In this paper, we build a NATREX model where the two economies are fully specified and allowed to interact. Our theoretical model offers the basis for empirical estimation of the euro/dollar equilibrium exchange rate that will be carried out in future research. JEL classification: F31; F36; F47Key words: NATREX; equilibrium exchange rate; euro/dollar; structural approach

Belief, Faith, and Hope: On the Rationality of Long-Term Commitment

I examine three attitudes: belief, faith, and hope. I argue that all three attitudes play the same role in rationalizing action. First, I explain two models of rational action—the decision-theory model and the belief-desire model. Both models entail there are two components of rational action: an epistemic component and a conative component. Then, using this framework, I show how belief, faith, and hope that p can all make it rational to accept, or act as if, p. I conclude by showing how my picture can explain how action-oriented commitments can be rational over time, both in the face of counterevidence and in the face of waning affections