Showing papers by "University of Illinois at Urbana–Champaign published in 1993"

AIN-93 Purified Diets for Laboratory Rodents: Final Report of the American Institute of Nutrition Ad Hoc Writing Committee on the Reformulation of the AIN-76A Rodent Diet

Abstract: For sixteen years, the American Institute of Nutrition Rodent Diets, AIN-76 and AIN-76A, have been used extensively around the world. Because of numerous nutritional and technical problems encountered with the diet during this period, it was revised. Two new formulations were derived: AIN-93G for growth, pregnancy and lactation, and AIN-93M for adult maintenance. Some major differences in the new formulation of AIN-93G compared with AIN-76A are as follows: 7 g soybean oil/100 g diet was substituted for 5 g corn oil/100 g diet to increase the amount of linolenic acid; cornstarch was substituted for sucrose; the amount of phosphorus was reduced to help eliminate the problem of kidney calcification in female rats; L-cystine was substituted for DL-methionine as the amino acid supplement for casein, known to be deficient in the sulfur amino acids; manganese concentration was lowered to one-fifth the amount in the old diet; the amounts of vitamin E, vitamin K and vitamin B-12 were increased; and molybdenum, silicon, fluoride, nickel, boron, lithium and vanadium were added to the mineral mix. For the AIN-93M maintenance diet, the amount of fat was lowered to 40 g/kg diet from 70 g/kg diet, and the amount of casein to 140 g/kg from 200 g/kg in the AIN-93G diet. Because of a better balance of essential nutrients, the AIN-93 diets may prove to be a better choice than AIN-76A for long-term as well as short-term studies with laboratory rodents.

Markov Chains and Stochastic Stability

Abstract: Meyn & Tweedie is back! The bible on Markov chains in general state spaces has been brought up to date to reflect developments in the field since 1996 - many of them sparked by publication of the first edition. The pursuit of more efficient simulation algorithms for complex Markovian models, or algorithms for computation of optimal policies for controlled Markov models, has opened new directions for research on Markov chains. As a result, new applications have emerged across a wide range of topics including optimisation, statistics, and economics. New commentary and an epilogue by Sean Meyn summarise recent developments and references have been fully updated. This second edition reflects the same discipline and style that marked out the original and helped it to become a classic: proofs are rigorous and concise, the range of applications is broad and knowledgeable, and key ideas are accessible to practitioners with limited mathematical background.

Review of the Satisfaction With Life Scale

Abstract: The Satisfaction With Life Scale (SWLS) was developed to assess satis-faction with the respondent’s life as a whole. The scale does not assess satisfaction with life domains such as health or finances but allows subjects to integrate and weight these domains in whatever way they choose. Normative data are presented for the scale, which shows good convergent validity with other scales and with other types of assessments of subjective well-being. Life satisfaction as assessed by the SWLS shows a degree of temporal stability (e.g., 0.54 for 4 years), yet the SWLS has shown sufficient sensitivity to be potentially valuable to detect change in life satis-faction during the course of clinical intervention. Further, the scale shows discrim-inant validity from emotional well-being measures. The SWLS is recommended as a complement to scales that focus on psychopathology or emotional well-being because it assesses an individuals’ conscious evaluative judgment of his or her life by using the person’s own criteria.

Universal approximation bounds for superpositions of a sigmoidal function

Abstract: Approximation properties of a class of artificial neural networks are established. It is shown that feedforward networks with one layer of sigmoidal nonlinearities achieve integrated squared error of order O(1/n), where n is the number of nodes. The approximated function is assumed to have a bound on the first moment of the magnitude distribution of the Fourier transform. The nonlinear parameters associated with the sigmoidal nodes, as well as the parameters of linear combination, are adjusted in the approximation. In contrast, it is shown that for series expansions with n terms, in which only the parameters of linear combination are adjusted, the integrated squared approximation error cannot be made smaller than order 1/n/sup 2/d/ uniformly for functions satisfying the same smoothness assumption, where d is the dimension of the input to the function. For the class of functions examined, the approximation rate and the parsimony of the parameterization of the networks are shown to be advantageous in high-dimensional settings. >

A Neural System for Error Detection and Compensation

Abstract: Humans can monitor actions and compensate for errors. Analysis of the human event-related brain potentials (ERPs) accompanying errors provides evidence for a neural process whose activity is specifically associated with monitoring and compensating for erroneous behavior. This error-related activity is enhanced when subjects strive for accurate performance but is diminished when response speed is emphasized at the expense of accuracy. The activity is also related to attempts to compensate for the erroneous behavior.

'Neural-gas' network for vector quantization and its application to time-series prediction

Abstract: A neural network algorithm based on a soft-max adaptation rule is presented. This algorithm exhibits good performance in reaching the optimum minimization of a cost function for vector quantization data compression. The soft-max rule employed is an extension of the standard K-means clustering procedure and takes into account a neighborhood ranking of the reference (weight) vectors. It is shown that the dynamics of the reference (weight) vectors during the input-driven adaptation procedure are determined by the gradient of an energy function whose shape can be modulated through a neighborhood determining parameter and resemble the dynamics of Brownian particles moving in a potential determined by the data point density. The network is used to represent the attractor of the Mackey-Glass equation and to predict the Mackey-Glass time series, with additional local linear mappings for generating output values. The results obtained for the time-series prediction compare favorably with the results achieved by backpropagation and radial basis function networks. >

The Role of Anomalous Data in Knowledge Acquisition: A Theoretical Framework and Implications for Science Instruction

Abstract: Understanding how science students respond to anomalous data is essential to understanding knowledge acquisition in science classrooms. This article presents a detailed analysis of the ways in which scientists and science students respond to such data. We postulate that there are seven distinct forms of response to anomalous data, only one of which is to accept the data and change theories. The other six responses involve discounting the data in various ways in order to protect the preinstructional theory. We analyze the factors that influence which of these seven forms of response a scientist or student will choose, giving special attention to the factors that make theory change more likely. Finally, we discuss the implications of our framework for science instruction.

Experimental Evidence for the Relationship of the Carbon Isotope Ratios of Whole Diet and Dietary Protein to Those of Bone Collagen and Carbonate

Abstract: The use of stable carbon isotopes for diet reconstruction is predicated on the assumption that you are what you eat. In other words, the carbon isotopic composition of animal tissues is assumed to be a direct and constant function of the diet. Is this assumption valid? Precise dietary reconstruction requires as accurate knowledge of the isotopic composition of locally available dietary resources, as well as an adequate understanding of the effects of nutrition, environment, and physiology on the diet-tissue function (van der Merwe 1982, 1989; Chisholm 1989; Norr 1990; Matson and Chisholm 1991; Tieszen 1991; Ambrose 1992). There is a systematic but poorly defined difference between the isotopic composition of the consumer tissues and that of the diet (an enrichment factor, expressed as Δ diet-tissue). Given the isotopic composition of a specific tissue, that of the diet or of other tissues may be calculated if the Δ diet-tissue difference factors are known. The dietary proportions of isotopically distinct food resources (e.g., C3 vs C4, or C3 vs marine) have thus been calculated from the δ 13C value of bone collagen (Δ13Cd-co) and bone apatite carbonate (Δ13Cd-ca). Deviations from actual or assumed average δ 13C values for dietary endmembers, and incorrect values for diet-to-tissue isotopic relationships, will lead to errors in the estimation of consumption of specific classes of resources. Experiments and observations designed to determine the diet-to-collagen stable isotope functions (Δ13Cd-co) however, have provided widely different values.

The relationship between income and subjective well-being: Relative or absolute?

Abstract: Although it appears that income and subjective well-being correlate in within-country studies (Diener, 1984), a debate has focused on whether this relationship is relative (Easterlin, 1974) or absolute (Veenhoven, 1988, 1991). The absolute argument advanced by Veenhoven states that income helps individuals meet certain universal needs and therefore that income, at least at lower levels, is a cause of subjective well-being. The relativity argument is based on the idea that the impact of income or other resources depends on changeable standards such as those derived from expectancies, habituation levels, and social comparisons. Two studies which empirically examine these positions are presented: one based on 18 032 college studies in 39 countries, and one based on 10 year longitudinal data in a probability sample of 4 942 American adults. Modest but significant correlations were found in the U.S. between income and well-being, but the cross-country correlations were larger. No evidence for the influence of relative standards on income was found: (1) Incomechange did not produce effects beyond the effect of income level per se, (2) African-Americans and the poorly educated did not derive greater happiness from specific levels of income, (3) Income produced the same levels of happiness in poorer and richer areas of the U.S., and (4) Affluence correlated with subjective well-being both across countries and within the U.S. Income appeared to produce lesser increases in subjective well-being at higher income levels in the U.S., but this pattern was not evident across countries. Conceptual and empirical questions about the universal needs position are noted. Suggestions for further explorations of the relativistic position are offered.

CHARM++: a portable concurrent object oriented system based on C++

Abstract: We describe Charm++, an object oriented portable parallel programming language based on C++. Its design philosophy, implementation, sample applications and their performance on various parallel machines are described. Charm++ is an explicitly parallel language consisting of C++ with a few extensions. It provides a clear separation between sequential and parallel objects. The execution model of Charm++ is message driven, thus helping one write programs that are latency-tolerant. The language supports multiple inheritance, dynamic binding, overloading, strong typing, and reuse for parallel objects, all of which are more difficult problems in a parallel context. Charm++ provides specific modes for sharing information between parallel objects. It is based on the Charm parallel programming system, and its runtime system implementation reuses most of the runtime system for Charm.

Contrarian Investment, Extrapolation, and Risk

Abstract: For many years, stock market analysts have argued that value strategies outperform the market. These value strategies call for buying stocks that have low prices relative to earnings, dividends, book assets, or other measures of fundamental value. While there is some agreement that value strategies produce higher returns, the interpretation of why they do so is more controversial. This paper provides evidence that value strategies yield higher returns because these strategies exploit the mistakes of the typical investor and not because these strategies are fundamentally riskier.

Riparian vegetated buffer strips in water‐quality restoration and stream management

Abstract: SUMMARY 1 A review is presented of the literature on riparian vegetated buffer strips (VBS) for use in stream-water-quality restoration and limitations associated with their use are discussed. The results are also presented of recent investigations on the effectiveness of a forested and a grass vegetated buffer strip for reducing shallow subsurface inputs of nutrients from agriculture to a stream in central Illinois, U.S.A. 2 Because riparian zones link the stream with its terrestrial catchment, they can modify, incorporate, dilute, or concentrate substances before they enter a lotic system. In small to mid-size streams forested riparian zones can moderate temperatures, reduce sediment inputs, provide important sources of organic matter, and stabilize stream banks. 3 Several questions on the utility and efficiency of vegetated buffer strips for stream restoration still remain unanswered, including: what types (grass v forest) are most efficient; do they become nutrient saturated; are they only temporary sinks; how does species composition influence effectiveness; and, what is the optimal width of buffer to facilitate nutrient reduction under different conditions? 4 Water samples were collected (1989–90) from lysimeters located at three depths (60, 120, and > 120cm) in an upland area planted in conventional row crops (corn and soybean) and in three adjacent riparian buffer treatments, a 39m wide grass buffer. a 16 m wide mature forested buffer, and a buffer planted in row-crops to the stream bank. Concentrations of dissolved and total phosphorus and nitrate-N in each sample were determined following major precipitation events over a seventeen month period. 5 Both the forested and grass VBS reduced nitrate-N concentrations in shallow groundwater (up to 90% reduction). On an annual basis the forested VBS was more effective at reducing concentrations of nitrate-N than was the grass VBS, but was less efficient at retaining total and dissolved P. 6 During the dormant season, both grass and forested buffer strips released dissolved and total P to the groundwater. The VBS apparently acted as a nutrient sink for much of the year, but also released accumulated nutrients during the remaining portion of the year. Periodic harvesting of plant biomass may reduce the amount of P released during the dormant season. 7 VBSs are not as effective in agriculture areas with tile drained fields. Alternative restoration practices such as discharging drain tiles into wetlands constructed parallel to the stream channel may prove to be a more effective means of controlling non-point-source agricultural inputs of nutrients in such areas.

Structure and binding of alkanethiolates on gold and silver surfaces: implications for self-assembled monolayers

Abstract: We performed ab initio geometry optimization of HS and CH 3 S on cluster models of Au(111), Au(100), Ag(111), and Ag(100) surfaces, at the RECP Hartree-Fock+electron correlation (MBPT2) level. From these we determined classical force field parameters, thus opening the possibility for realistic molecular dynamics (MD) simulations of self-assembled alkanethiolate monolayers on gold and silver surfaces. We find that there are two chemisorption modes, very close in energy, for thiolates on Au(111) surfaces. In the first, the surface-S-C bond angle is ∼180 o (sp hybridization), while in the second it is ∼104 o (spα 3 hybridization). This suggests a possible mechanism for the annealing of alkanethiolate monolayers

The mechanisms of analogical learning

Abstract: It is widely accepted that similarity is a key determinant of transfer. In this chapter I suggest that both of these venerable terms – similarity and transfer – refer to complex notions that require further differentiation. I approach the problem by a double decomposition: decomposing similarity into finer subclasses and decomposing learning by similarity and analogy into a set of component subprocesses. One thing reminds us of another. Mental experience is full of moments in which a current situation reminds us of some prior experience stored in memory. Sometimes such remindings lead to a change in the way we think about one or both of the situations. Here is an example reported by Dan Slobin (personal communication, April 1986). His daughter, Heida, had traveled quite a bit by the age of 3. One day in Turkey she heard a dog barking and remarked, “Dogs in Turkey make the same sound as dogs in America.… Maybe all dogs do. Do dogs in India sound the same?” Where did this question come from? According to Slobin's notebook, “She apparently noticed that while the people sounded different from country to country, the dogs did not.” The fact that only humans speak different languages may seem obvious to an adult, but for Heida to arrive at it by observation must have required a series of insights. She had to compare people from different countries and note that they typically sound different.

Strategic groups: a cognitive perspective

Abstract: The strategic group concept provides an attractive middle ground between firm and industry for both theory development and empirical analysis. To date, this concept has been defined by researchers in terms of secondary accounting and financial data, and a number of critics have questioned the validity of this work. Our research shows that industry participants share perceptions about strategic commonalities among firms, and that participants cluster competitors in subtle ways not reflected in extant academic research on strategic groups. Decision makers' perceptions and cognitions are phenomena that can be expected to influence industry evolution. They are of research interest as an additional source of data on firm commonalities which helps address concerns about previous strategic group research.

Critical thinking assessment

Abstract: (1993). Critical thinking assessment. Theory Into Practice: Vol. 32, Teaching for Higher Order Thinking, pp. 179-186.

Cross-language transfer of phonological awareness.

Abstract: A study investigated the factors influencing the English word identification performance of Spanish-speaking beginning readers. Beginning readers were administered tests of letter naming, Spanish phonological awareness, Spanish and English word recognition, and Spanish and English oral proficiency. Multiple-regression analyses revealed that the readers' performance on EngIish word and pseudoword recognition tests was predicted by the levels of both Spanish phonological awareness and Spanish word recognition, thus indicating cross-language transfer. In contrast, neither English nor Spanish oral proficiency affected word-identification performance. Results suggest a specific way in which first-language learning and experience can aid children in the beginning stages of reading

Parenting Practices and Peer Group Affiliation in Adolescence

Abstract: Social scientists have often assumed that parental influence is sharply curtailed at adolescence because of the rising counterinfluence of peer groups, over which parents have little control. The present study tested a conceptual model that challenged this view by arguing that parents retain a notable but indirect influence over their teenage child's peer associates. Data from a sample of 3,781 high school students (ages 15–19) indicated that specific parenting practices (monitoring, encouragement of achievement, joint decision making) were significantly associated with specific adolescent behaviors (academic achievement, drug use, self-reliance), which in turn were significantly related to membership in common adolescent crowds (jocks, druggies, etc.). Findings encourage investigators to assess more carefully parents' role in adolescents' peer group affiliations.

Arch models: properties, estimation and testing

Abstract: . The aim of this survey paper is to provide an account of some of the important developments in the autoregressive conditional heteroskedasticity (ARCH) model since its inception in a seminal paper by Engle (1982). This model takes account of many observed properties of asset prices, and therefore, various interpretations can be attributed to it. We start with the basic ARCH models and discuss their different interpretations. ARCH models have been generalized in different directions to accommodate more and more features of the real world. We provide a comprehensive treatment of many of the extensions of the original ARCH model. Next we discuss estimation and testing for ARCH models and note that these models lead to some interesting and unique problems. There have been numerous applications and we mention some of these as we present different models. The paper includes a glossary of the acronyms for the models we describe.

Greenfield vs. Acquisition: The Strategy of Japanese Investors in the United States

Abstract: Multinational firms can enter a foreign market by taking over existing local firms acquisitions or by setting up new ventures greenfield investments. Surprisingly, there has been limited empirical work on this topic. This paper examines the determinants of this choice by looking at Japanese entries into the United States. By focusing on firms of one country entering a single market, we are able to separate the impact of a firm's strategy from that of the characteristics of the target industry or country. This paper tests simultaneously a number of competing hypotheses. The results suggest that acquisitions are used by Japanese investors with weak competitive advantages, while investors with strong advantages find that greenfield investments are a more efficient way to transfer these advantages to the U.S. Acquisitions are also chosen to enter industries with either very high or very low growth rates, when entry is at a scale that is large relative to the parent, and when entry is into a different industry. The Japanese investor's previous experience of the U.S. market, its financial situation, and its status as a follower in an oligopolistic industry have no statistically significant impact on the entry mode. Neither do U.S. stock market conditions.

Experimental determination of the superconducting pairing state in YBCO from the phase coherence of YBCO-Pb dc SQUIDs.

Abstract: We present an experiment designed to determine directly the symmetry of the pairing state in the cuprate superconductors. From the magnetic flux modulation of YBCO-Pb dc SQUIDs, we determine the spatial anisotropy of the phase of the order parameter in single crystals of YBCO. The experimental results are complicated by SQUID asymmetries and the trapping of magnetic vortices, but taken as a whole give rather strong evidence for a phase shift of \ensuremath{\pi} that is predicted for the ${\mathit{d}}_{\mathit{x}}^{2\mathrm{\ensuremath{-}}}$${\mathit{y}}^{2}$ pairing state. This is further corroborated by single junction modulation measurements.

The Powers of literacy : a genre approach to teaching writing

Abstract: Foreword. Introduction: How a Genre Approach to Literacy Can Transform the Way Writing is Taught. Bill Cope and Mary Kalantzis. 1. Genre as Social Process. Gunther Kress. 2. Histories of Pedagogy, Cultures of Schooling Mary Kalantzis and Bill Cope. 3. The Power of Literacy and the Literacy of Power Bill Cope and Mary Kalantzis. 4. Gender and Genre: Feminist Subversion of Genre Fiction and Its Implications for Critical Literacy Anne Cranny-Francis. 5. A Contextual Theory of Language J R Martin. 6. Grammar: Making Meaning in Writing J R Martin and Joan Rothery. 7. Curriculum Genres: Planning for Effective Teaching Frances Christie. 8. Genre in Practice Mike Callaghan, Peter Knapp and Greg Noble. 9. Assessment: A Foundation for Effective Learning in the School Context. Mary Macken and Diana Slade. Bibliographical Essay: Developing the Theory and Practice of Genre-based Literacy. Bill Cope, Mary Kalantzis, Gunther Kress and Jim Martin compiled by Lorraine Murphy.

Design Patterns: Abstraction and Reuse of Object-Oriented Design

Abstract: We propose design patterns as a new mechanism for expressing object-oriented design experience. Design patterns identify, name, and abstract common themes in object-oriented design. They capture the intent behind a design by identifying objects, their collaborations, and the distribution of responsibilities. Design patterns play many roles in the object-oriented development process: they provide a common vocabulary for design, they reduce system complexity by naming and defining abstractions, they constitute a base of experience for building reusable software, and they act as building blocks from which more complex designs can be built. Design patterns can be considered reusable micro-architectures that contribute to an overall system architecture. We describe how to express and organize design patterns and introduce a catalog of design patterns. We also describe our experience in applying design patterns to the design of object-oriented systems.

Ribosomal RNA: a key to phylogeny.

Abstract: As molecular phylogeny increasingly shapes our understanding of organismal relationships, no molecule has been applied to more questions than have ribosomal RNAs. We review this role of the rRNAs and some of the insights that have been gained from them. We also offer some of the practical considerations in extracting the phylogenetic information from the sequences. Finally, we stress the importance of comparing results from multiple molecules, both as a method for testing the overall reliability of the organismal phylogeny and as a method for more broadly exploring the history of the genome.

Recent Variations of Sea Ice and Air Temperature in High Latitudes

Abstract: A gridded sea-ice database, for which the record length is now approaching four decades for the Arctic and two decades for the Antarctic, is summarized here. The sea-ice fluctuations derived from the dataset are characterized by temporal scales of several seasons to several years and spatial scales of 30-180 deg of longitude. The ice data are examined in conjunction with air temperature data for evidence of recent climate change in the polar regions. The arctic sea-ice variations over the past several decades are compatible with the corresponding air temperatures, which show a distinct warming that is strongest over northern land areas during the winter and spring. Statistically significant decreases of the summer extent of arctic ice are apparent in the sea-ice data, and new summer minima have been achieved three times in the past 15 years. There is no significant trend if ice extent in the Arctic during winter or in the Antarctic during any season.

Extraversion and neuroticism as predictors of objective life events: a longitudinal analysis.

Abstract: Data from a 4-year longitudinal study of young adults were used to examine the causal pathways between personality and life events. To reduce measurement artifacts, analyses were conducted using reports of more objective life events. It was found that extraversion predisposed participants to experience more positive objective life events, whereas neuroticism predisposed people to experience more negative objective events. In contrast, personality was somewhat stable. and life events were found not to have a prospective influence on it. Objective positive and negative life events covaried, suggesting that people who experience more of 1 type of event are also likely to experience more events of the opposite valence as well

Investment Analysis and the Adjustment of Stock Prices to Common Information

Abstract: In this article we are concerned with the effect of the number of investment analysts following a firm on the speed of adjustment of the firm's stock price to new information that has common effects across firms. It is found that returns on portfolios of firms that are followed by many analysts tend to lead those of firms that are followed by fewer analysts, even when the firms are of approximately the same size. Many analyst firms also tend to respond more rapidly to market returns than do few analyst firms, adjusting for firm size. This relation, however, is nonlinear, and the marginal effect of the number of analysts on the speed of price adjustment increases with the number of analysts. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.