Showing papers by "University of Georgia published in 1999"

Corporate Social Responsibility: Evolution of a Definitional Construct

Abstract: There is an impressive history associated with the evolution of the concept and definition of corporate social responsibility (CSR). In this article, the author traces the evolution of the CSR cons...

Emerging Marine Diseases--Climate Links and Anthropogenic Factors

Abstract: Mass mortalities due to disease outbreaks have recently affected major taxa in the oceans. For closely monitored groups like corals and marine mammals, reports of the frequency of epidemics and the number of new diseases have increased recently. A dramatic global increase in the severity of coral bleaching in 1997—98 is coincident with high El Nino temperatures. Such climate-mediated, physiological stresses may compromise host resistance and increase frequency of opportunistic diseases. Where documented, new diseases typically have emerged through host or range shifts of known pathogens. Both climate and human activities may have also accelerated global transport of species, bringing together pathogens and previously unexposed host populations. T he oceans harbor enormous biodiver- sity by terrestrial terms (1), much of which is still poorly described taxo- nomically. Even less well known are the dy- namics of intermittent, ephemeral, threshold phenomena such as disease outbreaks. De- spite decades of intense study of the biolog- ical agents structuring natural communities, the ecological and evolutionary impact of diseases in the ocean remains unknown, even when these diseases affect economically and ecologically important species. The paucity of baseline and epidemiological information on normal disease levels in the ocean chal- lenges our ability to assess the novelty of a recent spate of disease outbreaks and to de- termine the relative importance of increased pathogen transmission versus decreased host resistance in facilitating the outbreaks. Our objectives here are to review the prevalence of diseases of marine taxa to evaluate wheth- er it can be concluded that there has been a recent increase. We also assess the contribut- ing roles of human activity and global cli- mate, and evaluate the role of the oceans as incubators and conveyors of human disease agents. Is There an Increase in Diseases in the Ocean?

The NextGen Model Atmosphere Grid for 3000 ≤ Teff ≤ 10,000 K

Abstract: We present our NextGen Model Atmosphere grid for low-mass stars for effective temperatures larger than 3000 K. These LTE models are calculated with the same basic model assumptions and input physics as the VLMS part of the NextGen grid so that the complete grid can be used, e.g., for consistent stellar evolution calculations and for internally consistent analysis of cool star spectra. This grid is also the starting point for a large grid of detailed NLTE model atmospheres for dwarfs and giants. The models were calculated from 3000 to 10,000 K (in steps of 200 K) for 3.5{le}logthinspg{le}5.5 (in steps of 0.5) and metallicities of {minus}4.0{le}[M/H]{le}0.0. We discuss the results of the model calculations and compare our results to the Kurucz grid. Some comparisons to standard stars like Vega and the Sun are presented and compared with detailed NLTE calculations. {copyright} {ital {copyright} 1999.} {ital The American Astronomical Society}

Galloping Elephants: Developing Elements of a Theory of Effective Government Organizations

Abstract: Much of the theory and discourse on public bureaucracies treats them negatively, as if they incline inevitably toward weak performance. This orientation prevails in spite of considerable evidence that many government organizations perform very well, and in spite of many examples of their excellent performance. This article draws on the literature and research on effective government organizations to select and develop conceptual elements of a theory to explain their effectiveness. The available research suggests that such a theory should include the following components. supportive behaviors from external stakeholders such as political authorities; agency autonomy in refining and implementing its mission; high "mission valence" (an attractive mission); a strong, mission-oriented culture, and certain leadership behaviors. The discussion further posits that these factors enhance several forms of motivation of people in the agency-task motivation, mission motivation, and public service motivationthat can be differentiated but that must be linked together in effective government agencies. A corollary of this fact is the falsity of an equally common claim. that public and nonprofit organizations cannot, and on average do not, operate as efficiently as private businesses. . . . (Simon 1998, 1 1) The elephant serves as a virtually archetypical symbol of a large, cumbersome, lumbering being. Yet an elephant can run very fast. Pachyderm means thick-skinned, yet elephants display sensitivity in acts of altruism and nurturance beyond those that 1/Journal of Public Administration Research and Theory For valuable comments on earlier drafts of this paper, I am grateful to Bob Durant, Jameson Doig, Ken Meier, Patrick Wolf, and many of the participants in the theory panel at the 1998 Midwest Political Science Association meeting. I could not take all their comments and critiques into account in my revisions, so they bear no responsibility for limitations

Emerging infectious diseases and amphibian population declines.

Abstract: We review recent research on the pathology, ecology, and biogeography of two emerging infectious wildlife diseases, chytridiomycosis and ranaviral disease, in the context of host-parasite population biology. We examine the role of these diseases in the global decline of amphibian populations and propose hypotheses for the origins and impact of these panzootics. Finally, we discuss emerging infectious diseases as a global threat to wildlife populations.

Damage to photosystem II in symbiotic dinoflagellates: A determinant of coral bleaching

Abstract: Coral bleaching has been defined as a general phenomenon, whereby reef corals turn visibly pale because of the loss of their symbiotic dinoflagellates and/or algal pigments during periods of exposure to elevated seawater temperatures. During the summer of 1997, seawater temperatures in the Florida Keys remained at or above 30°C for more than 6 weeks, and extensive coral bleaching was observed. Bleached colonies of the dominant Caribbean reef-building species, Montastrea faveolata and Montastrea franksi, were sampled over a depth gradient from 1 to 17 m during this period of elevated temperature and contained lower densities of symbiotic dinoflagellates in deeper corals than seen in previous “nonbleaching” years. Fluorescence analysis by pulse-amplitude modulation fluorometry revealed severe damage to photosystem II (PSII) in remaining symbionts within the corals, with greater damage indicated at deeper depths. Dinoflagellates with the greatest loss in PSII activity also showed a significant decline in the D1 reaction center protein of PSII, as measured by immunoblot analysis. Laboratory experiments on the temperature-sensitive species Montastrea annularis, as well as temperature-sensitive and temperature-tolerant cultured symbiotic dinoflagellates, confirmed the temperature-dependent loss of PSII activity and concomitant decrease in D1 reaction center protein seen in symbionts collected from corals naturally bleached on the reef. In addition, variation in PSII repair was detected, indicating that perturbation of PSII protein turnover rates during photoinhibition at elevated temperatures underlies the physiological collapse of symbionts in corals susceptible to heat-induced bleaching.

Climate change and plant disease management

Abstract: ▪ Abstract Research on impacts of climate change on plant diseases has been limited, with most work concentrating on the effects of a single atmospheric constituent or meteorological variable on the host, pathogen, or the interaction of the two under controlled conditions. Results indicate that climate change could alter stages and rates of development of the pathogen, modify host resistance, and result in changes in the physiology of host-pathogen interactions. The most likely consequences are shifts in the geographical distribution of host and pathogen and altered crop losses, caused in part by changes in the efficacy of control strategies. Recent developments in experimental and modeling techniques offer considerable promise for developing an improved capability for climate change impact assessment and mitigation. Compared with major technological, environmental, and socioeconomic changes affecting agricultural production during the next century, climate change may be less important; it will, however, ...

Transposon Tn21, Flagship of the Floating Genome

Abstract: The transposon Tn21 and a group of closely related transposons (the Tn21 family) are involved in the global dissemination of antibiotic resistance determinants in gram-negative facultative bacteria. The molecular basis for their involvement is carriage by the Tn21 family of a mobile DNA element (the integron) encoding a site-specific system for the acquisition of multiple antibiotic resistance genes. The paradigm example, Tn21, also carries genes for its own transposition and a mercury resistance (mer) operon. We have compiled the entire 19,671-bp sequence of Tn21 and assessed the possible origins and functions of the genes it contains. Our assessment adds molecular detail to previous models of the evolution of Tn21 and is consistent with the insertion of the integron In2 into an ancestral Tn501-like mer transposon. Codon usage analysis indicates distinct host origins for the ancestral mer operon, the integron, and the gene cassette and two insertion sequences which lie within the integron. The sole gene of unknown function in the integron, orf5, resembles a puromycin-modifying enzyme from an antibiotic producing bacterium. A possible seventh gene in the mer operon (merE), perhaps with a role in Hg(II) transport, lies in the junction between the integron and the mer operon. Analysis of the region interrupted by insertion of the integron suggests that the putative transposition regulator, tnpM, is the C-terminal vestige of a tyrosine kinase sensor present in the ancestral mer transposon. The extensive dissemination of the Tn21 family may have resulted from the fortuitous association of a genetic element for accumulating multiple antibiotic resistances (the integron) with one conferring resistance to a toxic metal at a time when clinical, agricultural, and industrial practices were rapidly increasing the exposure to both types of selective agents. The compendium offered here will provide a reference point for ongoing observations of related elements in multiply resistant strains emerging worldwide.

Rapid accumulation and turnover of soil carbon in a re-establishing forest

Abstract: Present understanding of the global carbon cycle is limited by uncertainty over soil-carbon dynamics. The clearing of the world's forests, mainly for agricultural uses, releases large amounts of carbon to the atmosphere (up to 2 x 1015 gyr-1), much of which arises from the cultivation driving an accelerated decomposition of soil organic matter. Although the effects of cultivation on soil carbon are well studied, studies of soil-carbon recovery after cultivation are limited. Here we present a four-decade-long field study of carbon accumulation by pine ecosystems established on previously cultivated soils in South Carolina, USA. Newly accumulated carbon is tracked by its distinctive 14C signature, acquired around the onset of forest growth from thermonuclear bomb testing that nearly doubled atmospheric 14CO2 in the 1960s. Field data combined with model simulations indicate that the young aggrading forest rapidly incorporated bomb radiocarbon into the forest floor and the upper 60 cm of underlying mineral soil. By the 1990s, however, carbon accumulated only in forest biomass, forest floor, and the upper 7.5 cm of the mineral soil. Although the forest was a strong carbon sink, trees accounted for about 80%, the forest floor 20%, and mineral soil <1%, of the carbon accretion. Despite high carbon inputs to the mineral soil, carbon sequestration was limited by rapid decomposition, facilitated by the coarse soil texture and low-activity clay mineralogy.

The Problem of Underqualified Teachers in American Secondary Schools

Abstract: This article presents the results of a research project on the phenomenon of out-of-field teaching in American high schools–teachers teaching subjects for which they have little education or training. Over the past couple of years, the problem of out-of-field teaching has become a prominent topic in the realm of educational policy and reform, and the results of this research have been widely reported and commented on both by education policymakers and the national media. But unfortunately, out-of-field teaching is a problem that remains largely misunderstood. My research utilizes nationally representative data from the Schools and Staffing Survey, conducted by the National Center for Education Statistics. The purpose of this article is to summarize what my research has revealed about out-of-field teaching: how much of it goes on; to what extent it varies across different subjects, across different kinds of schools, and across different kinds of classrooms; and finally, the reasons for its prevalence in Am...

Screening for plant growth-promoting rhizobacteria to promote early soybean growth

Abstract: Although many studies have been conducted to identify the specific traits by which plant growth-promoting rhizobacteria (PGPR) promote plant growth, usually they were limited to studying just one or two of these traits. We selected 116 isolates from bulk soil and the rhizosphere of soybean [Glycine max (L.) Merr.] and examined them for a wide array of traits that might increase early soybean growth in nonsterile soil (PGPR traits). A subsample of 23 isolates, all but one of which tested positive for one or more of these PGPR traits, was further screened for traits associated with biocontrol, (brady)rhizobial inhibition, and rhizosphere competence. Six of eight isolates positive for 1-aminocyclopropane-1-carboxylate (ACC, a precursor of ethylene) deaminase production, four of seven isolates positive for siderophore production, three of four isolates positive for β-1,3-glucanase production, and two of five isolates positive for P solubilization increased at least one aspect of early soybean growth. One isolate. which did not share any of the PGPR traits tested in vitro except antagonism to Sclerotium rolfsii and Sclerotinia sclerotiorum, also promoted soybean growth. One of the 23 isolates changed bradyrhizo-promoted soybean growth. One of the 23 isolates changed bradyrhizobial nodule occupancy. Although the presence of a PGPR trait in vitro does not guarantee that a particular isolate is a PGPR, the results suggest that rhizobacteria able to produce ACC deaminase and, to a lesser extent, β-1,3-glucanase or siderophores or those able to solubilize P in vitro may increase early soybean growth in nonsterile soil.

Modeling the impact of public management: implications of structural context

Abstract: Management theory suggests that management matters in public organizations-its impact is conditional on structure and often nonlinear in form. This article distills much of the theoretical work on management in public organizations into a formal, testable model. Management is presented as more crucial in networks than in more structured hierarchies. Management influences organization performance by 1) creating structure for the organization and thus system stability, 2) buffering the organization from environmental influences, and 3) exploiting opportunities in the environment. Decisions about which of these actions to take are at the core of strategic management. This article is the first step in a full model of managerial action in public organizations.

Effects of resource limitation on a detrital‐based ecosystem

Abstract: We examined the importance of terrestrial detrital inputs to secondary productivity of a headwater stream. Following a year of pretreatment studies on two headwater streams, we excluded terrestrial litter inputs (=treatment) to one stream while using the other as a reference. We excluded litter for 3 yr followed by 1 yr of small woody debris (≤10 cm diameter) removal and litter exclusion. Monthly benthic samples were collected from dominant mixed substrate (cobble, pebble, and sand-silt) as well as from moss-covered bedrock outcrop substrates. We used randomized intervention analysis (RIA) to test the null hypotheses that no change in abundance or biomass of functional feeding groups or specific taxa occurred in the treatment stream relative to the reference stream. Benthic organic matter was significantly lower in mixed substrate habitats of the treatment stream; however, small woody debris did not show a significant reduction prior to manual removal during year 4. At the end of the treatment period, tot...

Econometric Estimation of Technical and Environmental Efficiency: An Application to Dutch Dairy Farms

Abstract: In this article we estimate the technical and environmental efficiency of a panel of Dutch dairy farms. Nitrogen surplus, arising from the application of excessive amounts of manure and chemical fertilizer, is treated as an environmentally detrimental input. A stochastic translog production frontier is specified to estimate the output-oriented technical efficiency. Environmental efficiency is estimated as the input-oriented technical efficiency of a single input, the nitrogen surplus of each farm. The mean output-oriented technical efficiency is rather high, 0.894, but the mean input-oriented environmental efficiency is only 0.441. Intensive dairy farms are both technically and environmentally more efficient than extensive farms.

Dependence of fluorescence lifetimes of Y2O3 : Eu3+ nanoparticles on the surrounding medium

Abstract: The radiative lifetime, ${\ensuremath{\tau}}_{R},$ of the ${}^{5}{D}_{0}$ metastable excited state of ${\mathrm{Eu}}^{3+}$ ions in nanocrystalline monoclinic ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ samples is about four times longer than that in the micron size powder of the same material. The ${\mathrm{Eu}}^{3+}$ radiative lifetime was measured in nanocrystals surrounded with air as well as those immersed in different liquids. It is shown that the radiative lifetime changes with the index of refraction of the immersion medium and provides a unique test of the standard formula relating ${\ensuremath{\tau}}_{R}$ and the oscillator strength. The magnitude of the effect is determined by the ``filling factor'' (the fraction of the sample volume occupied by nanocrystals) which can therefore be determined.

The NEXTGEN Model Atmosphere Grid. II. Spherically Symmetric Model Atmospheres for Giant Stars with Effective Temperatures between 3000 and 6800 K

Abstract: We present the extension of our NextGen model atmosphere grid to the regime of giant stars. The input physics of the models presented here is nearly identical to that of the NextGen dwarf atmosphere models; however, spherical geometry is used self-consistently in the model calculations (including the radiative transfer). We revisit the discussion of the effects of spherical geometry on the structure of the atmospheres and the emitted spectra and discuss the results of non-LTE calculations for a few selected models.

The Impact of High Involvement Work Processes on Organizational Effectiveness A Second-Order Latent Variable Approach

Abstract: Using a second-order latent variable approach with 3,570 participants across 49 organizations, the current study examined the impact of high involvement work processes upon organizational effective...

Motivational bases of affective organizational commitment: A partial test of an integrative theoretical model

Abstract: A theoretical process-oriented model of affective organizational commitment is presented to explain the psychological mechanisms that may trigger individuals' affective commitment to their organization. An operational version of the model is tested, along with several theoretically based alternative models, using meta-analytic correlations and structural equations modelling. Results suggest that intrinsic motivation is a partial mediator of the relationship between several exogenous variables (job characteristics and work context variables) and work attitudes (affective organizational commitment and general job satisfaction). In addition, affective commitment and general job satisfaction are related to turnover behaviour, whereas only affective commitment is related to absenteeism. Implications for theory and applied research are discussed.

The Pore Size of Non-Graminaceous Plant Cell Walls Is Rapidly Decreased by Borate Ester Cross-Linking of the Pectic Polysaccharide Rhamnogalacturonan II.

Abstract: The walls of suspension-cultured Chenopodium album L. cells grown continually for more than 1 year on B-deficient medium contained monomeric rhamnogalacturonan II (mRG-II) but not the borate ester cross-linked RG II dimer (dRG-II-B). The walls of these cells had an increased size limit for dextran permeation, which is a measure of wall pore size. Adding boric acid to growing B-deficient cells resulted in B binding to the wall, the formation of dRG-II-B from mRG-II, and a reduction in wall pore size within 10 min. The wall pore size of denatured B-grown cells was increased by treatment at pH ≤ 2.0 or by treatment with Ca 2+ -chelating agents. The acid-mediated increase in wall pore size was prevented by boric acid alone at pH 2.0 and by boric acid together with Ca 2+ , but not by Na + or Mg 2+ ions at pH 1.5. The Ca 2+ -chelator-mediated increase in pore size was partially reduced by boric acid. Our results suggest that B-mediated cross-linking of RG-II in the walls of living plant cells generates a pectin network with a decreased size exclusion limit for polymers. The formation, stability, and possible functions of a borate ester cross-linked pectic network in the primary walls of nongraminaceous plant cells are discussed.

Review of the Foundations of Network Environ Analysis

Abstract: This article introduces and summarizes the foundations of network environ analysis and describes four primary properties resulting from this research. These properties—dominance of indirect effects (Higashi and Patten 1986), network amplification (Patten and others 1990), network homogenization (Patten and others 1990), and network synergism (Patten 1991)—provide insight into the behavior of holistic network interactions. In short, amplification, homogenization, and indirect effects demonstrate the influence of the indirect flows in a system to show that energy or matter cycling allows flow to return to the same component many times and tend to become evenly distributed within the network. Synergism relates direct and indirect, qualitative relations to show that network organization is, on the whole, more mutualistic than is apparent from direct interactions alone. Using network analysis, objects can be studied as part of a connected system and the indirect effects can be identified and quantified. This is a fundamentally different way of investigating ecosystems, and it gives a quantitative foundation to the widely held perception of the interconnectedness of nature.

Comparison of Fungal Laccases and Redox Mediators in Oxidation of a Nonphenolic Lignin Model Compound

Abstract: Conventional pulp-bleaching techniques with chlorine or chlorine-based chemicals can, under certain conditions, generate chlorinated organic compounds that are toxic to the environment. The pulp and paper industry is facing an increasing pressure from environmentally concerned organizations to replace the conventional bleaching techniques with environmentally benign ones. Enzymatic bleaching methods have recently drawn much attention as being environmentally friendly. In addition to xylanase, laccase has been the most actively investigated enzyme for biobleaching of kraft pulp because laccase can be produced in large amounts at a reasonable price and use cheap oxygen as an electron acceptor. However, expensive redox mediators are still a hurdle in the implementation of laccase in pulp bleaching. Laccase (EC 1.10.3.1) belongs to a family of multi-copper oxidases that are widespread in numerous fungi, in various plant species (18), in the bacterium Azospirillum lipoferum (10), and in a dozen of studied insects (25). Laccase has various functions, including participation in lignin biosynthesis (21), plant pathogenicity (22), the degradation of plant cell walls (12, 17), insect sclerotization (3), bacterial melanization (10), and melanin-related virulence for humans (26). Chemically, all of these functions of laccases are related to oxidation of a range of aromatic substances. However, the net effect of such oxidations could be very different and even work in opposite directions. Plant laccases, for example, oxidize monolignols to form polymeric lignins, whereas laccases from white-rot fungi degrade and depolymerize lignins. In the degradation of lignin by white-rot fungi, the redox potential of the lignin-degrading enzymes has long been believed to play a crucial role because nonphenolic subunits, the most predominant lignin substructures in wood, have high redox potentials. The well-studied lignin peroxidase is able to oxidize nonphenolic aromatic compounds with very high ionization potentials such as 1,2-dimethoxybenzene (E1/2 = 1,500 mV) and veratryl alcohol (14, 20). Lignin peroxidase was thus once believed to be a key enzyme for fungal degradation of lignin, whereas laccase was believed to be less important because it could not oxidize veratryl alcohol (a typical model compound for nonphenolic lignin). The highest redox potential of a laccase reported so far does not exceed 800 mV, which is believed not to be high enough to oxidize a nonphenolic lignin structure. However, it has been demonstrated that laccase is able to oxidize some compounds (redox mediators) with a higher redox potential than laccase itself, although the mechanism by which this happens is not known (2, 7). In the presence of such redox mediators, laccase is also able to oxidize nonphenolic lignin model compounds and decrease pulp kappa number to a great extent (5, 8). Several effective redox mediators have been reported so far (2, 5, 6, 8, 13). The importance of the redox potential of laccases in the oxidation of lignin model compounds by laccase/mediator systems will be addressed here. While much effort has been devoted to search for more effective redox mediators, the laccase parameters governing lignin degradation and pulp bleaching are still not fully elucidated. In an effort to determine these parameters, we compared the ability of different laccases for the oxidation of lignin model compounds in a laccase-mediator system. More specifically, four laccases from different fungal species were purified and used to oxidize the β-O-4 dimer I (the most predominant lignin substructure) and phenol red (a phenolic lignin model compound). Laccases from the different sources were found to oxidize dimer I and phenol red at different rates. Criteria for a better laccase and more effective laccase-mediator systems for pulp bleaching have been suggested.

Action Research: Rethinking Lewin

Abstract: Fifty years after Kurt Lewin invented the idea of action research, action research remains an umbrella term for a host of activities intended to foster change on the group, organizational, and even...

Beginning teachers : Beliefs and classroom actions

Abstract: The current national priority for systemic approaches to the reform of science and mathematics education has led to unprecedented interest in research on the efficacy of science and mathematics teacher preparation programs. In response to this priority, a focus on collaborative approaches to educational reform and to research on educational reform resulted in a national collaborative research consortium of insitutions of higher education. The consortium was formed to investigate the following question about secondary science teacher education: What are the perceptions, beliefs, and classroom performances of beginning secondary teachers as related to their philosophies of teaching and their content pedagogical skills? The research design and instrumentation yielded detailed descriptions that elicited knowledge and beliefs held by beginning teachers about science, the nature of teaching and learning, and their philosophy of teaching. An analysis of video portfolios of beginning teachers provided classroom-based evidence of their performance in both subject matter and pedagogical dimensions of teaching. Among the findings from this 3-year exploratory study were that teachers graduated from their teacher preparation programs with a range of knowledge and beliefs about: how teachers should interact with subject content and processes, what teachers should be doing in the classroom, what students should be doing in the classroom, philosophies of teaching, and how they perceived themselves as classroom teachers. Beginning teachers described their practices as very student-centered. Observations of these teaching practices contrasted starkly with teacher beliefs: While teachers professed student-centered beliefs, they behaved in teacher-centered ways. Undertaking intensive, collaborative studies such as the one described in this article, is the beginning of efforts through which the science and mathematics education communities can strive to address the needs of students, teachers, teacher educators, and other stakeholders working to establish a common vision for excellent instruction and systemic, long-lasting reform. © 1999 John Wiley & Sons, Inc. J Res Sci Teach 36: 930–954, 1999

CONFLICT IN MARRIAGE: Implications for Working with Couples

Abstract: ▪ Abstract The investigation of marital conflict has reached a crossroads. Over 25 years of research on marital conflict behavior yields a relatively clear picture of its topography, but its relevance for changing the marital relationship remains controversial. We can continue to amass observations in a relatively atheoretical manner and hope that patterns capable of guiding clinical activity will emerge, or we can begin creating a unified theoretical framework to indicate new directions for clinical activity and empirical investigation. Before exploring the latter option, this chapter reviews briefly the impact of marital conflict on mental, physical, and family health and what is known about the nature of conflict in marriage. After highlighting some recent theoretically grounded advances, we illustrate how conceptualizing marital conflict behavior as goal directed provides an integrative theoretical framework for treatment, prevention, and marital conflict research.

The Configuration Interaction Method: Advances in Highly Correlated Approaches

Abstract: Highly correlated configuration interaction (CI) wavefunctions going beyond the simple singles and doubles (CISD) model space can provide very reliable potential energy surfaces, describe electronic excited states, and yield benchmark energies and molecular properties for use in calibrating more approximate methods. Unfortunately, such wavefunctions are also notoriously difficult to evaluate due to their extreme computational demands. The dimension of a full CI procedure, which represents the exact solution of the electronic Schrodinger equation for a fixed one-particle basis set, grows factorially with the number of electrons and basis functions. For very large configuration spaces, the number of CI coupling coefficients becomes prohibitively large to store on disk; these coefficients must be evaluated as needed in a so-called direct CI procedure. Work done by several groups since 1980 has focused on using Slater determinants rather than spin ( S ^ 2 ) eigenfunctions because coupling coefficients are easier to compute with the former. We review the fundamentals of the configuration interaction method and discuss various determinant-based CI algorithms. Additionally, we consider some applications of highly correlated CI methods.

Using the science writing heuristic as a tool for learning from laboratory investigations in secondary science

Abstract: This article presents and discusses preliminary research on a new heuristic tool for learning from laboratory activities in secondary science. The tool, called the science writing heuristic, can be used by teachers as a framework from which to design classroom activities. Theoretically, the science writing heuristic represents a bridge between traditional laboratory reports and types of writing that promote personal construction of meaning. Two eighth-grade classes participated in using the science writing heuristic during an 8-week stream study. The teacher and one of the researchers collaboratively developed activities based on the science writing heuristic that the teacher implemented. Nineteen target students were studied in depth. Characteristics of report writing and students' understanding of the nature of science were investigated, using interpretive techniques. There is evidence that use of the science writing heuristic facilitated students to generate meaning from data, make connections among procedures, data, evidence, and claims, and engage in metacognition. Students' vague understandings of the nature of science at the beginning of the study were modified to more complex, rich, and specific understandings. The implications of the study for writing in science classrooms is discussed. © 1999 John Wiley & Sons, Inc. J Res Sci Teach 36: 1065–1084, 1999