University of Minnesota, Duluth

An ensemble consists of a set of individually trained classifiers (such as neural networks or decision trees) whose predictions are combined when classifying novel instances. Previous research has shown that an ensemble is often more accurate than any of the single classifiers in the ensemble. Bagging (Breiman, 1996c) and Boosting (Freund & Shapire, 1996; Shapire, 1990) are two relatively new but popular methods for producing ensembles. In this paper we evaluate these methods on 23 data sets using both neural networks and decision trees as our classification algorithm. Our results clearly indicate a number of conclusions. First, while Bagging is almost always more accurate than a single classifier, it is sometimes much less accurate than Boosting. On the other hand, Boosting can create ensembles that are less accurate than a single classifier -- especially when using neural networks. Analysis indicates that the performance of the Boosting methods is dependent on the characteristics of the data set being examined. In fact, further results show that Boosting ensembles may overfit noisy data sets, thus decreasing its performance. Finally, consistent with previous studies, our work suggests that most of the gain in an ensemble's performance comes in the first few classifiers combined; however, relatively large gains can be seen up to 25 classifiers when Boosting decision trees.

The emergence of publications on extracellular RNA (exRNA) and extracellular vesicles (EV) has highlighted the potential of these molecules and vehicles as biomarkers of disease and therapeutic targets. These findings have created a paradigm shift, most prominently in the field of oncology, prompting expanded interest in the field and dedication of funds for EV research. At the same time, understanding of EV subtypes, biogenesis, cargo and mechanisms of shuttling remains incomplete. The techniques that can be harnessed to address the many gaps in our current knowledge were the subject of a special workshop of the International Society for Extracellular Vesicles (ISEV) in New York City in October 2012. As part of the "ISEV Research Seminar: Analysis and Function of RNA in Extracellular Vesicles (evRNA)", 6 round-table discussions were held to provide an evidence-based framework for isolation and analysis of EV, purification and analysis of associated RNA molecules, and molecular engineering of EV for therapeutic intervention. This article arises from the discussion of EV isolation and analysis at that meeting. The conclusions of the round table are supplemented with a review of published materials and our experience. Controversies and outstanding questions are identified that may inform future research and funding priorities. While we emphasize the need for standardization of specimen handling, appropriate normative controls, and isolation and analysis techniques to facilitate comparison of results, we also recognize that continual development and evaluation of techniques will be necessary as new knowledge is amassed. On many points, consensus has not yet been achieved and must be built through the reporting of well-controlled experiments.

People develop feelings of ownership for a variety of objects, material and immaterial in nature. We refer to this state as psychological ownership. Building on and extending previous scholarship, the authors offer a conceptual examination of this construct. After defining psychological ownership, they address “why” it exists and “how” it comes into being. They propose that this state finds its roots in a set of intraindividual motives (efficacy and effectance, self-identity, and having a place to dwell). In addition, they discuss the experiences that give rise to psychological ownership and propose several positive and negative consequences of this state. The authors’ work provides a foundation for the development of a comprehensive theory of psychological ownership and the conceptual underpinnings for empirical testing.

The preparation, structure, and chemistry of hypervalent iodine compounds are reviewed with emphasis on their synthetic application. Compounds of iodine possess reactivity similar to that of transition metals, but have the advantage of environmental sustainability and efficient utilization of natural resources. These compounds are widely used in organic synthesis as selective oxidants and environmentally friendly reagents. Synthetic uses of hypervalent iodine reagents in halogenation reactions, various oxidations, rearrangements, aminations, C-C bond-forming reactions, and transition metal-catalyzed reactions are summarized and discussed. Recent discovery of hypervalent catalytic systems and recyclable reagents, and the development of new enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important achievement in the field of hypervalent iodine chemistry. One of the goals of this Review is to attract the attention of the scientific community as to the benefits of using hypervalent iodine compounds as an environmentally sustainable alternative to heavy metals.

Throughout this century there have been many efforts to reform the medical curriculum. These efforts have largely been unsuccessful in producing fundamental changes in the training of medical students. The author challenges the traditional notion that changes to medical education are most appropriately made at the level of the curriculum, or the formal educational programs and instruction provided to students. Instead, he proposes that the medical school is best thought of as a "learning environment" and that reform initiatives must be undertaken with an eye to what students learn instead of what they are taught. This alternative framework distinguishes among three interrelated components of medical training: the formal curriculum, the informal curriculum, and the hidden curriculum. The author gives basic definitions of these concepts, and proposes that the hidden curriculum needs particular exploration. To uncover their institution's hidden curricula, he suggests that educators and administrators examine four areas: institutional policies, evaluation activities, resource-allocation decisions, and institutional "slang." He also describes how accreditation standards and processes might be reformed. He concludes with three recommendations for moving beyond curriculum reform to reconstruct the overall learning environment of medical education, including how best to move forward with the Medical School Objectives Project sponsored by the AAMC.

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTChemistry of Polyvalent IodineViktor V. Zhdankin*† and Peter J. Stang‡View Author Information Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, and Department of Chemistry, 315 S 1400 E, Rm 2020, University of Utah, Salt Lake City, Utah 84112*Corresponding author (e-mail, [email protected]).†University of Minnesota Duluth.‡University of Utah.Cite this: Chem. Rev. 2008, 108, 12, 5299–5358Publication Date (Web):November 6, 2008Publication History Received5 May 2008Published online6 November 2008Published inissue 10 December 2008https://pubs.acs.org/doi/10.1021/cr800332chttps://doi.org/10.1021/cr800332creview-articleACS PublicationsCopyright © 2008 American Chemical SocietyRequest reuse permissionsArticle Views29668Altmetric-Citations1638LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Alcohols,Iodine,Oxidation,Reagents,Salts Get e-Alerts

Lake 227, a small lake in the Precambrian Shield at the Experimental Lakes Area (ELA), has been fertilized for 37 years with constant annual inputs of phosphorus and decreasing inputs of nitrogen to test the theory that controlling nitrogen inputs can control eutrophication. For the final 16 years (1990-2005), the lake was fertilized with phosphorus alone. Reducing nitrogen inputs increasingly favored nitrogen-fixing cyanobacteria as a response by the phytoplankton community to extreme seasonal nitrogen limitation. Nitrogen fixation was sufficient to allow biomass to continue to be produced in proportion to phosphorus, and the lake remained highly eutrophic, despite showing indications of extreme nitrogen limitation seasonally. To reduce eutrophication, the focus of management must be on decreasing inputs of phosphorus.

Building upon the observation that individuals feel ownership toward a variety of targets, we suggest that under certain conditions, organizational members can develop feelings of ownership toward the organization and various organizational factors. We define psychological ownership, identify its “roots” and the primary “routes” through which it develops, and propose certain organizational outcomes. We discuss the conceptual distinctiveness of psychological ownership from a set of related constructs and suggest some theoretical and managerial implications of our theory.

Abstract While strategy scholars primarily focus on internal firm capabilities and network scholars typically examine network structure, we posit that firms with superior network structures may be better able to exploit their internal capabilities and thus enhance their performance. We examine how innovative capabilities—both those of focal firms and those they access through their networks—influence the performance of Canadian mutual fund companies. We find that a firm's innovative capabilities and its network structure both enhance firm performance, while the innovativeness of its contacts does not do so directly. Innovative firms that also bridge structural holes get a further performance boost, suggesting that firms need to develop network‐enabled capabilities—capabilities accruing to innovative firms that bridge structural holes. Copyright © 2005 John Wiley & Sons, Ltd.

Iron is an essential nutrient for virtually all organisms. The IRT1 (iron-regulated transporter) gene of the plant Arabidopsis thaliana, encoding a probable Fe(II) transporter, was cloned by functional expression in a yeast strain defective for iron uptake. Yeast expressing IRT1 possess a novel Fe(II) uptake activity that is strongly inhibited by Cd. IRT1 is predicted to be an integral membrane protein with a metal-binding domain. Data base comparisons and Southern blot analysis indicated that IRT1 is a member of a gene family in Arabidopsis. Related sequences were also found in the genomes of rice, yeast, nematodes, and humans. In Arabidopsis, IRT1 is expressed in roots, is induced by iron deficiency, and has altered regulation in plant lines bearing mutations that affect the iron uptake system. These results provide the first molecular insight into iron transport by plants.

Abstract An increasing number of scholars and practitioners have emphasized the importance of ‘feelings of ownership’ for the organization (even when employees are not legal owners). In this exploratory study, we examine the relationships of psychological ownership with work attitudes and work behaviors. We start by developing hypotheses based on the psychology of possession and psychological ownership literatures. We then test these hypotheses with data from three field samples, using responses from over 800 employees, as well as manager and peer observations of employee behavior. Results demonstrate positive links between psychological ownership for the organization and employee attitudes (organizational commitment, job satisfaction, organization‐based self‐esteem), and work behavior (performance and organizational citizenship). More important, psychological ownership increased explained variance in organization‐based self‐esteem and organizational citizenship behavior (both peer and supervisor observations of citizenship), over and above the effects of job satisfaction and organizational commitment. Contrary to prior theoretical work on psychological ownership, results, however, fail to show an incremental value of psychological ownership in predicting employee performance. Copyright © 2004 John Wiley & Sons, Ltd.

Abstract In this first worldwide synthesis of in situ and satellite‐derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade −1 ) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widely geographically distributed, and their warming is associated with interactions among different climatic factors—from seasonally ice‐covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade −1 ) to ice‐free lakes experiencing increases in air temperature and solar radiation (0.53°C decade −1 ). The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes.

As human populations increase and land-use intensifies, toxic and unsightly nuisance blooms of algae are becoming larger and more frequent in freshwater lakes. In most cases, the blooms are predominantly blue-green algae (Cyanobacteria), which are favored by low ratios of nitrogen to phosphorus. In the past half century, aquatic scientists have devoted much effort to understanding the causes of such blooms and how they can be prevented or reduced. Here we review the evidence, finding that numerous long-term studies of lake ecosystems in Europe and North America show that controlling algal blooms and other symptoms of eutrophication depends on reducing inputs of a single nutrient: phosphorus. In contrast, small-scale experiments of short duration, where nutrients are added rather than removed, often give spurious and confusing results that bear little relevance to solving the problem of cyanobacteria blooms in lakes.

Mammalian hibernators undergo a remarkable phenotypic switch that involves profound changes in physiology, morphology, and behavior in response to periods of unfavorable environmental conditions. The ability to hibernate is found throughout the class Mammalia and appears to involve differential expression of genes common to all mammals, rather than the induction of novel gene products unique to the hibernating state. The hibernation season is characterized by extended bouts of torpor, during which minimal body temperature (Tb) can fall as low as -2.9 degrees C and metabolism can be reduced to 1% of euthermic rates. Many global biochemical and physiological processes exploit low temperatures to lower reaction rates but retain the ability to resume full activity upon rewarming. Other critical functions must continue at physiologically relevant levels during torpor and be precisely regulated even at Tb values near 0 degrees C. Research using new tools of molecular and cellular biology is beginning to reveal how hibernators survive repeated cycles of torpor and arousal during the hibernation season. Comprehensive approaches that exploit advances in genomic and proteomic technologies are needed to further define the differentially expressed genes that distinguish the summer euthermic from winter hibernating states. Detailed understanding of hibernation from the molecular to organismal levels should enable the translation of this information to the development of a variety of hypothermic and hypometabolic strategies to improve outcomes for human and animal health.

This study examines the association between measures of earnings quality and auditor industry specialization. Prior work has examined the association between auditor brand name and earnings quality, using auditor brand name to proxy for audit quality. Recent work has hypothesized that auditor industry specialization also contributes to audit quality. Extending this literature, we compare the absolute level of discretionary accruals (DAC) and earnings response coefficients (ERC) of firms audited by industry specialists with those of firms not audited by industry specialists. We restrict our study to clients of Big 6 (and later Big 5) auditors to control for brand name. Because industry specialization is unobservable, we use multiple proxies for it. After controlling for variables established in prior work to be related to DAC and the ERC, we find clients of industry specialist auditors have lower DAC and higher ERC than clients of nonspecialist auditors. This finding is consistent with clients of industry specialists having higher earnings quality than clients of nonspecialists.

Until now, Quaternary paleoecologists have regarded evolution as a slow process relative to climate change, predicting that the primary biotic response to changing climate is not adaptation, but instead (1) persistence in situ if changing climate remains within the species' tolerance limits, (2) range shifts (migration) to regions where climate is currently within the species' tolerance limits, or (3) extinction. We argue here that all three of these outcomes involve evolutionary processes. Genetic differentiation within species is ubiquitous, commonly via adaptation of populations to differing environmental conditions. Detectable adaptive divergence evolves on a time scale comparable to change in climate, within decades for herbaceous plant species, and within centuries or millennia for longer-lived trees, implying that biologically significant evolutionary response can accompany temporal change in climate. Models and empirical studies suggest that the speed with which a population adapts to a changing environment affects invasion rate of new habitat and thus migration rate, population growth rate and thus probability of extinction, and growth and mortality of individual plants and thus productivity of regional vegetation. Recent models and experiments investigate the stability of species tolerance limits, the influence of environmental gradients on marginal populations, and the interplay of demography, gene flow, mutation rate, and other genetic processes on the rate of adaptation to changed environments. New techniques enable ecologists to document adaptation to changing conditions directly by resurrecting ancient populations from propagules buried in decades-old sediment. Improved taxonomic resolution from morphological studies of macrofossils and DNA recovered from pollen grains and macroremains provides additional information on range shifts, changes in population sizes, and extinctions. Collaboration between paleoecologists and evolutionary biologists can refine interpretations of paleorecords, and improve predictions of biotic response to anticipated climate change.

Solar neutrino measurements from 1258 days of data from the Super-Kamiokande detector are presented. The measurements are based on recoil electrons in the energy range 5.0--20.0 MeV. The measured solar neutrino flux is $2.32\ifmmode\pm\else\textpm\fi{}0.03(\mathrm{stat}{)}_{\ensuremath{-}0.07}^{+0.08}(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{6}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$, which is $45.1\ifmmode\pm\else\textpm\fi{}0.5(\mathrm{stat}{)}_{\ensuremath{-}1.4}^{+1.6}(\mathrm{syst})%$ of that predicted by the BP2000 SSM. The day vs night flux asymmetry $({\ensuremath{\Phi}}_{n}\ensuremath{-}{\ensuremath{\Phi}}_{d})/{\ensuremath{\Phi}}_{\mathrm{average}}$ is $0.033\ifmmode\pm\else\textpm\fi{}0.022(\mathrm{stat}{)}_{\ensuremath{-}0.012}^{+0.013}(\mathrm{syst})$. The recoil electron energy spectrum is consistent with no spectral distortion. For the hep neutrino flux, we set a $90%$ C.L. upper limit of $40\ifmmode\times\else\texttimes\fi{}{10}^{3}{\mathrm{cm}}^{\ensuremath{-}2}{\mathrm{s}}^{\ensuremath{-}1}$, which is 4.3 times the BP2000 SSM prediction.

On numerous occasions it has been suggested that an individual’s self-esteem, formed around work and organizational experiences, plays a significant role in determining employee motivation, work-related attitudes and behaviors. We review more than a decade of research on an organization-based conceptualization of self-esteem. It is observed that sources of organization structure, signals about worth from the organization, as well as, success-building role conditions predict organization-based self-esteem. In addition, organization-based self-esteem is related to job satisfaction, organizational commitment, motivation, citizenship behavior, in-role performance, and turnover intentions, as well as, other important organization-related attitudes and behaviors. Explanations for these effects and directions for future research are discussed.

Trinucleotide expansions cause disease by both protein- and RNA-mediated mechanisms. Unexpectedly, we discovered that CAG expansion constructs express homopolymeric polyglutamine, polyalanine, and polyserine proteins in the absence of an ATG start codon. This repeat-associated non-ATG translation (RAN translation) occurs across long, hairpin-forming repeats in transfected cells or when expansion constructs are integrated into the genome in lentiviral-transduced cells and brains. Additionally, we show that RAN translation across human spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1) CAG expansion transcripts results in the accumulation of SCA8 polyalanine and DM1 polyglutamine expansion proteins in previously established SCA8 and DM1 mouse models and human tissue. These results have implications for understanding fundamental mechanisms of gene expression. Moreover, these toxic, unexpected, homopolymeric proteins now should be considered in pathogenic models of microsatellite disorders.

WordNet::Similarity is a freely available software package that makes it possible to measure the semantic similarity and relatedness between a pair of concepts (or synsets). It provides six measures of similarity, and three measures of relatedness, all of which are based on the lexical database WordNet. These measures are implemented as Perl modules which take as input two concepts, and return a numeric value that represents the degree to which they are similar or related. 1