Showing papers by "Ohio State University published in 1999"
TL;DR: An overview of pattern clustering methods from a statistical pattern recognition perspective is presented, with a goal of providing useful advice and references to fundamental concepts accessible to the broad community of clustering practitioners.
Abstract: Clustering is the unsupervised classification of patterns (observations, data items, or feature vectors) into groups (clusters). The clustering problem has been addressed in many contexts and by researchers in many disciplines; this reflects its broad appeal and usefulness as one of the steps in exploratory data analysis. However, clustering is a difficult problem combinatorially, and differences in assumptions and contexts in different communities has made the transfer of useful generic concepts and methodologies slow to occur. This paper presents an overview of pattern clustering methods from a statistical pattern recognition perspective, with a goal of providing useful advice and references to fundamental concepts accessible to the broad community of clustering practitioners. We present a taxonomy of clustering techniques, and identify cross-cutting themes and recent advances. We also describe some important applications of clustering algorithms such as image segmentation, object recognition, and information retrieval.
14,054 citations
TL;DR: A generic approach to cancer classification based on gene expression monitoring by DNA microarrays is described and applied to human acute leukemias as a test case and suggests a general strategy for discovering and predicting cancer classes for other types of cancer, independent of previous biological knowledge.
Abstract: Although cancer classification has improved over the past 30 years, there has been no general approach for identifying new cancer classes (class discovery) or for assigning tumors to known classes (class prediction). Here, a generic approach to cancer classification based on gene expression monitoring by DNA microarrays is described and applied to human acute leukemias as a test case. A class discovery procedure automatically discovered the distinction between acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) without previous knowledge of these classes. An automatically derived class predictor was able to determine the class of new leukemia cases. The results demonstrate the feasibility of cancer classification based solely on gene expression monitoring and suggest a general strategy for discovering and predicting cancer classes for other types of cancer, independent of previous biological knowledge.
12,530 citations
TL;DR: The Im-Pesaran-Shin (IPS) test as discussed by the authors relaxes the restrictive assumption of the LL test and is best viewed as a test for summarizing the evidence from independent tests of the sample hypothesis.
Abstract: The panel data unit root test suggested by Levin and Lin (LL) has been widely used in several applications, notably in papers on tests of the purchasing power parity hypothesis. This test is based on a very restrictive hypothesis which is rarely ever of interest in practice. The Im–Pesaran–Shin (IPS) test relaxes the restrictive assumption of the LL test. This paper argues that although the IPS test has been offered as a generalization of the LL test, it is best viewed as a test for summarizing the evidence from a number of independent tests of the sample hypothesis. This problem has a long statistical history going back to R. A. Fisher. This paper suggests the Fisher test as a panel data unit root test, compares it with the LL and IPS tests, and the Bonferroni bounds test which is valid for correlated tests. Overall, the evidence points to the Fisher test with bootstrap-based critical values as the preferred choice. We also suggest the use of the Fisher test for testing stationarity as the null and also in testing for cointegration in panel data.
6,652 citations
Book•
01 Oct 1999TL;DR: Wendt as discussed by the authors describes four factors which can drive structural change from one culture to another - interdependence, common fate, homogenization, and self-restraint - and examines the effects of capitalism and democracy in the emergence of a Kantian culture in the West.
Abstract: Drawing upon philosophy and social theory, Social Theory of International Politics develops a theory of the international system as a social construction. Alexander Wendt clarifies the central claims of the constructivist approach, presenting a structural and idealist worldview which contrasts with the individualism and materialism which underpins much mainstream international relations theory. He builds a cultural theory of international politics, which takes whether states view each other as enemies, rivals or friends as a fundamental determinant. Wendt characterises these roles as 'cultures of anarchy', described as Hobbesian, Lockean and Kantian respectively. These cultures are shared ideas which help shape state interests and capabilities, and generate tendencies in the international system. The book describes four factors which can drive structural change from one culture to another - interdependence, common fate, homogenization, and self-restraint - and examines the effects of capitalism and democracy in the emergence of a Kantian culture in the West.
4,573 citations
TL;DR: A fundamental misconception about this issue is that the minimum sample size required to obtain factor solutions that are adequately stable and that correspond closely to population factors is not the optimal sample size.
Abstract: The factor analysis literature includes a range of recommendations regarding the minimum sample size necessary to obtain factor solutions that are adequately stable and that correspond closely to population factors. A fundamental misconception about this issue is that the minimum sample size, or the
4,166 citations
TL;DR: The authors suggest that the mechanism involved is the perception-behavior link, the recently documented finding that the mere perception of another's behavior automatically increases the likelihood of engaging in that behavior oneself.
Abstract: The chameleon effect refers to nonconscious mimicry of the postures, mannerisms, facial expressions, and other behaviors of one's interaction partners, such that one's behavior passively and unintentionally changes to match that of others in one's current social environment. The authors suggest that the mechanism involved is the perception-behavior link, the recently documented finding (e.g., J. A. Bargh, M. Chen, & L. Burrows, 1996) that the mere perception of another's behavior automatically increases the likelihood of engaging in that behavior oneself. Experiment 1 showed that the motor behavior of participants unintentionally matched that of strangers with whom they worked on a task. Experiment 2 had confederates mimic the posture and movements of participants and showed that mimicry facilitates the smoothness of interactions and increases liking between interaction partners. Experiment 3 showed that dispositionally empathic individuals exhibit the chameleon effect to a greater extent than do other people.
3,711 citations
TL;DR: The Universal Declaration of Human Rights (UDHR) as mentioned in this paper is the moral backbone of more than two hundred human rights instruments that are now a part of our world and has been a source of hope and inspiration to thousands of groups and millions of oppressed individuals.
Abstract: In his 1941 State of the Union message President Franklin Roosevelt called for the protection worldwide of four essential freedoms: "the freedom of speech and expression, the freedom of worship, the freedom from want, and the freedom from fear". Roosevelt's enunciation of these freedoms was part of a movement that gathered strength in the 1940s and strived to make the protection of human rights part of the conditions for peace at the end of World War II. In 1947 Eleanor Roosevelt was elected to be the chair of the United Nations Commission on Human Rights that was charged to produce a separate document for this purpose.The resulting Universal Declaration of Human Rights, adopted in 1948, has become the moral backbone of more than two hundred human rights instruments that are now a part of our world. The document has been a source of hope and inspiration to thousands of groups and millions of oppressed individuals.Johannes Morsink offers a behind-the-scenes account of the Declaration's origins and development. He reports on the detailed discussions that took place in the United Nations, tells us which countries argued for or against each provision of the Declaration, explains why certain important amendments were rejected, and shows how common revulsion toward the Holocaust provided the consensus needed to adopt this universal code of ethics.
3,538 citations
TL;DR: The approximate sampling distribution of the log response ratio is given, why it is a particularly useful metric for many applications in ecology, and how to use it in meta-analysis are discussed.
Abstract: Meta-analysis provides formal statistical techniques for summarizing the results of independent experiments and is increasingly being used in ecology. The response ratio (the ratio of mean outcome in the experimental group to that in the control group) and closely related measures of proportionate change are often used as measures of effect magnitude in ecology. Using these metrics for meta-analysis requires knowledge of their statistical properties, but these have not been previously derived. We give the approximate sampling distribution of the log response ratio, discuss why it is a particularly useful metric for many applications in ecology, and demonstrate how to use it in meta-analysis. The meta-analysis of response-ratio data is illustrated using experimental data on the effects of increased atmospheric CO2 on plant biomass responses.
3,042 citations
TL;DR: A review of research and theory on the motivations for maintaining ingroup boundaries and the implications of ingroup boundary protection for intergroup relations, conflict, and conflict prevention can be found in this paper.
Abstract: Allport (1954) recognized that attachment to one's ingroups does not necessarily require hostility toward outgroups. Yet the prevailing approach to the study of ethnocentrism, ingroup bias, and prejudice presumes that ingroup love and outgroup hate are reciprocally related. Findings from both cross-cultural research and laboratory experiments support the alternative view that ingroup identification is independent of negative attitudes toward outgroups and that much ingroup bias and intergroup discrimination is motivated by preferential treatment of ingroup members rather than direct hostility toward outgroup members. Thus to understand the roots of prejudice and discrimination requires first of all a better understanding of the functions that ingroup formation and identification serve for human beings. This article reviews research and theory on the motivations for maintenance of ingroup boundaries and the implications of ingroup boundary protection for intergroup relations, conflict, and conflict prevention.
2,768 citations
TL;DR: A conceptual introduction to ontologies and their role in information systems and AI is provided and how ontologies clarify the domain's structure of knowledge and enable knowledge sharing is discussed.
Abstract: This survey provides a conceptual introduction to ontologies and their role in information systems and AI. The authors also discuss how ontologies clarify the domain's structure of knowledge and enable knowledge sharing.
1,763 citations
TL;DR: Results suggest that the PrSC scale confounds two unrelated, motivationally distinct dispositions--rumination and reflection--and that this confounding may account for the "self-absorption paradox" implicit in PrSC research findings: Higher PrSC scores are associated with more accurate and extensive self-knowledge yet higher levels of psychological distress.
Abstract: A distinction between ruminative and reflective types of private self-attentiveness is introduced and evaluated with respect to L. R. Goldberg's (1982) list of 1,710 English trait adjectives (Study 1), the five-factor model of personality (FFM) and A. Fenigstein, M. F. Scheier, and A. Buss's (1975) Self-Consciousness Scales (Study 2), and previously reported correlates and effects of private self-consciousness (PrSC; Studies 3 and 4). Results suggest that the PrSC scale confounds two unrelated, motivationally distinct dispositions--rumination and reflection--and that this confounding may account for the "self-absorption paradox" implicit in PrSC research findings: Higher PrSC scores are associated with more accurate and extensive self-knowledge yet higher levels of psychological distress. The potential of the FFM to provide a comprehensive framework for conceptualizing self-attentive dispositions, and to order and integrate research findings within this domain, is discussed.
TL;DR: The World Health Organization classification of hematologic malignancies, including lymphoid, myeloid, histiocytic, and mast cell neoplasms, has produced a new and exciting degree of cooperation and communication between oncologists and pathologists from around the world, which should facilitate progress in the understanding and treatment ofhematologicmalignancies.
TL;DR: In this paper, a model of social capital that has explicit links to theories of Social capital was proposed and analyzed over a 20-year period, showing that the results do not consistently support Putnam's claim of a decline in social capital.
Abstract: Despite a great deal of interest in a possible decline of social capital in the United States, scholars have not reached a consensus on the trend. This article improves upon previous research by providing a model of social capital that has explicit links to theories of social capital and that analyzes multiple indicators of social capital over a 20‐year period. The results do not consistently support Putnam's claim of a decline in social capital, showing instead some decline in a general measure of social capital, a decline in trust in individuals, no general decline in trust in institutions, and no decline in associations.
TL;DR: The tumour spectrum associated with germline mutations of DNA‐mismatch‐repair genes involves 8 or more organ sites, suggesting a need to develop methods to screen for extra‐colonic cancer also.
Abstract: Excessive incidence of various cancers is a challenging feature of the hereditary-non-polyposis-colorectal-cancer (HNPCC) syndrome. This study estimated the cancer incidences in HNPCC compared with the general population. Individuals in a cohort of 1763 members of 50 genetically diagnosed families were categorized according to their genetic status as mutation carriers, non-carriers, or individuals at 50 or 25% risk of being a carrier. Incidences of cancers in these groups were compared with those in the Finnish population overall. In 360 mutation carriers, standardized incidence ratios (SIR) were significantly increased for colorectal [68; 95% confidence intervals (CI), 56 to 81], endometrial (62; 95% CI, 44 to 86), ovarian (13; 95% CI, 5.3 to 25), gastric (6.9; 95% CI, 3.6 to 12), biliary tract (9.1; 95% CI, 1.1 to 33), uro-epithelial (7.6; 95% CI, 2.5 to 18) and kidney (4.7; 95% CI, 1 to 14) cancers and for central-nervous-system tumours (4.5; 95% CI, 1.2 to 12). The SIR increased with increasing likelihood of being a mutation carrier. The cumulative cancer incidences were 82, 60, 13 and 12% for colorectal, endometrial, gastric and ovarian cancers respectively. For other tumours associated with increased risk, corresponding incidences were below 4%. Interestingly, the incidence of endometrial cancer (60%) exceeded that for colorectal cancer in women (54%). The tumour spectrum associated with germline mutations of DNA-mismatch-repair genes involves 8 or more organ sites, suggesting a need to develop methods to screen for extra-colonic cancer also. Int. J. Cancer 81:214–218, 1999. © 1999 Wiley-Liss, Inc.
TL;DR: In this article, the authors argue that the risks of equity are shared among more investors with different portfolio exposures and hence a different "appetite" for bearing certain risks, and that equity market risk premiums should fall for all companies in countries with access to global markets.
Abstract: International financial markets are progressively becoming one huge, integrated, global capital market—a development that is contributing to higher stock prices in developed as well as developing economies. For companies that are large and visible enough to attract global investors, having a global shareholder base means having a lower cost of capital and hence a greater equity value for two main reasons:
First, because the risks of equity are shared among more investors with different portfolio exposures and hence a different “appetite” for bearing certain risks, equity market risk premiums should fall for all companies in countries with access to global markets. Although the largest reductions in cost of capital resulting from globalization will be experienced by companies in liberalizing economies that are gaining access to the global markets for the first time, risk premiums can also be expected to fall for firms in long-integrated markets as well.
Second, when firms in countries with less-developed capital markets raise capital in the public markets of countries (like the U.S.) with highly developed markets, they get more than lower-cost capital; they also import at least aspects of the corporate governance systems that prevail in those markets. For companies accustomed to less-developed markets, raising capital overseas is likely to mean that more sophisticated investors, armed with more advanced technologies, will participate in monitoring their performance and management. And, in a virtuous cycle, more effective monitoring increases investor confidence in the future performance of those companies and so improves the terms on which they raise capital.
Besides reducing market risk premiums and improving corporate governance, globalization also affects the systematic risk, or “beta,” of individual companies. In global markets, the beta of a firm's equity depends on how the stock contributes to the volatility not of the home market portfolio, but of the world market portfolio. For companies with access to global capital markets whose profitability is tied more closely to the local than to the global economy, use of the traditional Capital Asset Pricing Model (CAPM) will overstate the cost of capital because risks that are not diversifiable within a national economy can be diversified by holding a global portfolio. Thus, to reflect the new reality of a globally determined cost of capital, all companies with access to global markets should consider using a global CAPM that views a company as part of the global portfolio of stocks. In making this argument, the article reviews the growing body of academic studies that provide evidence of the predictive power of the global CAPM as well as the reduction in world risk premiums.
VU University Amsterdam1, University of Pennsylvania2, University of Maryland, Baltimore3, Cornell University4, New Mexico State University5, Qatar Airways6, Louisiana Tech University7, Université du Québec8, Stockholm School of Economics9, University of Buenos Aires10, University of Alberta11, University of Indonesia12, University of Queensland13, Bellevue University14, London Business School15, Western Illinois University16, University of Memphis17, Fudan University18, Boğaziçi University19, University of Reading20, University of South Africa21, Athens University of Economics and Business22, Ludwig Maximilian University of Munich23, University of Calgary24, University of Burgundy25, National Sun Yat-sen University26, Hong Kong Polytechnic University27, Indian Institute of Management Ahmedabad28, City University of Hong Kong29, Lincoln University (New Zealand)30, University of Lethbridge31, Wayne State University32, University College Dublin33, Indiana University34, Kuwait University35, Technion – Israel Institute of Technology36, University of Giessen37, The Chinese University of Hong Kong38, University of Zurich39, Fordham University40, Complutense University of Madrid41, University of Nebraska–Lincoln42, INCAE Business School43, National University of Malaysia44, Opole University45, Hong Kong Baptist University46, Tbilisi State University47, Ohio State University48, University of Wrocław49, Alexandria University50, University of San Francisco51, Melbourne Business School52, Bentley University53, University of Los Andes54, I-Shou University55, Johannes Kepler University of Linz56, International Labour Organization57, Smith College58, Copenhagen Business School59, Chungnam National University60, National University of Singapore61, Tilburg University62, Hong Kong University of Science and Technology63, Thammasat University64, Sewanee: The University of the South65, FernUniversität Hagen66, Soochow University (Suzhou)67, University of St. Gallen68, Kumamoto University69
TL;DR: In this paper, the authors focus on culturally endorsed implicit theories of leadership (CLTs) and show that attributes associated with charismatic/transformational leadership will be universally endorsed as contributing to outstanding leadership.
Abstract: This study focuses on culturally endorsed implicit theories of leadership (CLTs). Although cross-cultural research emphasizes that different cultural groups likely have different conceptions of what leadership should entail, a controversial position is argued here: namely that attributes associated with charismatic/transformational leadership will be universally endorsed as contributing to outstanding leadership. This hypothesis was tested in 62 cultures as part of the Global Leadership and Organizational Behavior Effectiveness (GLOBE) Research Program. Universally endorsed leader attributes, as well as attributes that are universally seen as impediments to outstanding leadership and culturally contingent attributes are presented here. The results support the hypothesis that specific aspects of charismatic/transformational leadership are strongly and universally endorsed across cultures.
TL;DR: Cacioppo et al. as mentioned in this paper showed that the common metric governing approach-withdrawal is generally a single dimension at response stages that itself is the consequence of multiple operations, such as the activation function for positivity (appetition) and the activation functions for negativity (aversion), at earlier affective processing stages.
Abstract: The affect system has been shaped by the hammer and chisel of adaptation and natural selection such that form follows function. The characteristics of the system thus differ across the nervous system as a function of the unique constraints existent at each level. For instance, although physical limitations constrain behavioral expressions and incline behavioral predispositions toward a bipolar (good-bad, approach-withdraw) organization, these limiting conditions lose their power at the level of underlying mechanisms. According to the authors' model of evaluative space (J. T. Cacioppo & G. G. Berntson, 1994; J. T. Cacioppo, W. L. Gardner, & G. G. Berntson, 1997), the common metric governing approach-withdrawal is generally a single dimension at response stages that itself is the consequence of multiple operations, such as the activation function for positivity (appetition) and the activation function for negativity (aversion), at earlier affective processing stages.
01 Jan 1999
TL;DR: In this paper, a review describes the experiments performed during the last few decades which enhance knowledge of the pitting of aluminum, specifically, metastable and stable pits, pit chemistry and the effect of intermetallics on pitting.
TL;DR: The flf-1 mutant requires a greater than normal amount of an exogenous gibberellin to decrease flowering time compared with the wild type or with vernalization-responsive late-flowering mutants, suggesting that the FLF gene product may block the promotion of flowering by GAs.
Abstract: A MADS box gene, FLF (for FLOWERING LOCUS F ), isolated from a late-flowering, T-DNA-tagged Arabidopsis mutant, is a semidominant gene encoding a repressor of flowering. The FLF gene appears to integrate the vernalization-dependent and autonomous flowering pathways because its expression is regulated by genes in both pathways. The level of FLF mRNA is downregulated by vernalization and by a decrease in genomic DNA methylation, which is consistent with our previous suggestion that vernalization acts to induce flowering through changes in gene activity that are mediated through a reduction in DNA methylation. The flf-1 mutant requires a greater than normal amount of an exogenous gibberellin (GA3) to decrease flowering time compared with the wild type or with vernalization-responsive late-flowering mutants, suggesting that the FLF gene product may block the promotion of flowering by GAs. FLF maps to a region on chromosome 5 near the FLOWERING LOCUS C gene, which is a semidominant repressor of flowering in late-flowering ecotypes of Arabidopsis.
TL;DR: All but one of the classical linkage groups can now be assigned to a corresponding molecular linkage group on the basis of in situ segregation or linkage reports in the literature.
Abstract: A number of molecular genetic maps of the soybean [Glycine max (L.) Merr.] have been developed over the past 10 yr. These maps are primarily based on restriction fragment length polymorphism (RFLP) markers. Parental surveys have shown that most RFLP loci have only two known alleles. However, because the soybean is an ancient polyploid, RFLP probes typically hybridize and map to more than one position in the genome. Thus, the polymorphic potential of an RFLP probe is primarily a function of the frequency of the two alleles at each locus the probe detects. In contrast, simple sequence repeat (SSR) markers are single locus markers with multiple alleles. The polymorphic potential of an SSR marker is dependent on the number of alleles and their frequencies. Single locus markers provide an unambiguous means of defining linkage group homology across mapping populations. The objective of the work reported here was to develop and map a large set of SSR markers. A total of 606 SSR loci were mapped in one or more of three populations: the USDA/Iowa State G. max × G. soja F 2 population, the Univ. of Utah Minsoy × Noir 1 recombinant inbred population, and the Univ. of Nebraska Clark × Harosoy F 2 population. Each SSR mapped to a single locus in the genome, with a map order that was essentially identical in all three populations. Many SSR loci were segregating in two or all three populations. Thus, it was relatively simple to align the 20+ linkage groups derived from each of the three populations into a consensus set of 20 homologous linkage groups presumed to correspond to the 20 pairs of soybean chromosomes. On the basis of in situ segregation or linkage reports in the literature all but one of the classical linkage groups can now be assigned to a corresponding molecular linkage group.
Book•
22 Apr 1999TL;DR: The design approach based on the regularization is generalized for mechanical systems and it is shown that stability of zero dynamics should be taken into account when the regular form consists of blocks of second-order equations.
Abstract: Introduction Examples of Dynamic Systems with Sliding Modes Sliding Modes in Relay and Variable Structure Systems Multidimensional Sliding Modes Outline of Sliding Mode Control Methodology Mathematical Background Problem Statement Regularization Equivalent Control Method Physical Meaning of Equivalent Control Existence Conditions Design Concepts Introductory Example Decoupling Regular Form Invariance Unit Control Second-Order Sliding Mode Control Sliding Mode Control of Pendulum Systems Design Methodology Cart Pendulum Rotational Inverted Pendulum (Model) Rotational Inverted Pendulum (Control) Simulation and Experiment Results for Rotational Inverted Pendulum Control of Linear Systems Eigenvalue Placement Invariant Systems Sliding Mode Dynamic Compensators Ackermanns Formula Output Feedback Sliding Mode Control Control of Time-Varying Systems Sliding Mode Observers Linear Asymptotic Observers Observers for Linear Time-Invariant Systems Observers for Linear Time-Varying Systems Observer for Linear Systems with Binary Output Integral Sliding Mode Motivation Problem Statement Design Principles Perturbation and Uncertainty Estimation Examples Summary The Chattering Problem Problem Analysis Boundary Layer Solution Observer-Based Solution Regular Form Solution Disturbance Rejection Solution State-Dependent Gain Method Equivalent Control-Dependent Gain Method Multiphase Chattering Suppression Comparing the Different Solutions Discrete-Time and Delay Systems Introduction to Discrete-Time Systems Discrete-Time Sliding Mode Concept Linear Discrete-Time Systems with Known Parameters Linear Discrete-Time Systems with Unknown Parameters Introduction to Systems with Delays and Distributed Systems Linear Systems with Delays Distributed Systems Summary Electric Drives DC Motors Permanent-Magnet Synchronous Motors Induction Motors Summary Power Converters DC/DC Converters Boost-Type AC/DC Converters DC/AC Converter Summary Advanced Robotics Dynamic Modeling Trajectory Tracking Control Gradient Tracking Control Application Examples Automotive Applications Air/Fuel Ratio Control Camless Combustion Engine Observer for Automotive Alternator
TL;DR: This study completely sequenced and compared genomic clones containing the SMN genes and suggests that the exon 7 nucleotide change affects the activity of an exon splice enhancer which causes SMA.
Abstract: Spinal muscular atrophy (SMA) is a recessive disorder characterized by loss of motor neurons in the spinalcord. It is caused by mutations in the telomeric survival motor neuron 1 (SMN1) gene. Alterations within analmost identical copy gene, the centromeric survival motor neuron 2 (SMN2) gene produce no known pheno-typic effect. The exons of the two genes differ by just two nucleotides, neither of which alters the encodedamino acids. At the genomic level, only five nucleotides that differentiate the two genes from one anotherhave been reported. The entire genomic sequence of the two genes has not been determined. Thus, differ-ences which might explain why SMN1is the SMA gene are not readily apparent. In this study, we have com-pletely sequenced and compared genomic clones containing the SMNgenes. The two genes show strikingsimilarity, with the homology being unprecedented between two different yet functional genes. The only crit-ical difference in an ~32 kb region between the two SMNgenes is the C→→→→T base change 6 bp inside exon 7.This alteration but not other variations in the SMNgenes affects the splicing pattern of the genes. The majorityof the transcript from the SMN1locus is full length, whereas the majority of the transcript produced by theSMN2locus lacks exon 7. We suggest that the exon 7 nucleotide change affects the activity of an exon spliceenhancer. In SMA patients, the loss of SMN1but the presence of SMN2results in low levels of full-lengthSMNtranscript and therefore low SMN protein levels which causes SMA.INTRODUCTIONProximal spinal muscular atrophy (SMA) is an autosomalrecessive neuromuscular disorder characterized by destructionof motor neurons in the anterior horn of the spinal cord. SMAhas an estimated incidence of 1 in 10 000 live births, with a car-rier frequency of ~1 in 50 people (1). Childhood onset SMA isclassified into three groups on the basis of age at onset andclinical course (2); type I SMA (Werdnig–Hoffman disease) isthe most severe form, with onset before the age of 6 monthsand death usually occurring within the first 2 years. Type IISMA is intermediate in severity. Onset occurs at ~18 monthsand patients never gain the ability to walk. Type III SMA(Kugelberg–Welander disease) is the mildest form of the dis-ease with onset after 18 months. Type III patients are able tostand and walk.All three forms of proximal SMA are due to mutations in thetelomeric but not centromeric survival motor neuron (SMN)genes (3–11). The full-length cDNAs of the two genes areidentical except for single nucleotide differences in exons 7and 8, yet their transcriptional products are not the same.SMN1 produces a majority of the full-length cDNA;SMN2produces mostly transcript lacking exon 7 (3). We have shownpreviously that promoter differences do not account for the dif-ferent levels of full-length transcript from the two genes (12).Instead, the exon 7 difference between the two genes affectssplicing, causing increased levels of full-length transcript fromSMN1 as compared with SMN2 (13).The SMN protein is a 38 kDa polypeptide which is ubiqui-tously expressed (14,15). It is found at especially high levels inthe spinal motor neurons. The exact function of the proteinremains unknown. However, recent studies have implicated itsinvolvement in mRNA biogenesis. Specifically, SMN has been
TL;DR: In this article, the authors explore the relationship among experience, environment, and performance at the subsidiary level and find that the intensity and diversity of host country experience is an important predictor of subunit performance.
Abstract: Does organizational learning as measured by experience in a host country affect international expansion performance? If so, does such a relationship between experience and performance hold over time? How do the environmental forces in the host country affect such a relationship? Focusing on organizational learning by multinational enterprises (MNEs) operating in a transition economy, this study answers these three critical questions by exploring the relationships among experience, environment, and performance at the subsidiary level. Based on a recent survey of 108 MNE subunits operating in China, we find that the intensity and diversity of host country experience is an important predictor of subunit performance. While the positive effect of the intensity of experience on performance diminishes over time, the impact of the diversity of experience on performance remains unchanged. Moreover, for MNEs experiencing greater environmental dynamism, complexity, and hostility, there is a stronger positive relationship between experience and performance.
Institute of Arctic and Alpine Research1, Stony Brook University2, University of Gothenburg3, Marine Biological Laboratory4, University of Alberta5, University of Basel6, University of Zurich7, University of British Columbia8, Ohio State University9, Michigan State University10, University of Oulu11, Université du Québec à Trois-Rivières12, Cold Regions Research and Engineering Laboratory13, Komarov Botanical Institute14, King's College London15, Florida International University16, University of Bergen17, University of Wyoming18, University of London19
TL;DR: Results indicate that key phenological events such as leaf bud burst and flowering occurred earlier in warmed plots throughout the study period; however, there was little impact on growth cessation at the end of the season.
Abstract: The International Tundra Experiment (ITEX) is a collaborative, multisite experiment using a common temperature manipulation to examine variability in species response across climatic and geographic gradients of tundra ecosystems. ITEX was designed specifically to examine variability in arctic and alpine species response to increased temperature. We compiled from one to four years of experimental data from 13 different ITEX sites and used meta-analysis to analyze responses of plant phenology, growth, and reproduction to experimental warming. Results indicate that key phenological events such as leaf bud burst and flowering occurred earlier in warmed plots throughout the study period; however, there was little impact on growth cessation at the end of the season. Quantitative measures of vegetative growth were greatest in warmed plots in the early years of the experiment, whereas reproductive effort and success increased in later years. A shift away from vegetative growth and toward reproductive effort and success in the fourth treatment year suggests a shift from the initial response to a secondary response. The change in vegetative response may be due to depletion of stored plant reserves, whereas the lag in reproductive response may be due to the formation of flower buds one to several seasons prior to flowering. Both vegetative and reproductive responses varied among life-forms; herbaceous forms had stronger and more consistent vegetative growth responses than did woody forms. The greater responsiveness of the herbaceous forms may be attributed to their more flexible morphology and to their relatively greater proportion of stored plant reserves. Finally, warmer, low arctic sites produced the strongest growth responses, but colder sites produced a greater reproductive response. Greater resource investment in vegetative growth may be a conservative strategy in the Low Arctic, where there is more competition for light, nutrients, or water, and there may be little opportunity for successful germination or seedling development. In contrast, in the High Arctic, heavy investment in producing seed under a higher temperature scenario may provide an opportunity for species to colonize patches of unvegetated ground. The observed differential response to warming suggests that the primary forces driving the response vary across climatic zones, functional groups, and through time.
TL;DR: In this article, the ultimate values for compressive strength, Young's modulus, and toughness of cylindrical specimens of unitary aspect ratios and uniform grain-size distributions were extrapolated for hydroxyapatite (HAP) to 70 MPa, 9.2 GPa, and 0.36 J cm(-3).
Abstract: The ultimate values for compressive strength, Young's modulus, and toughness of cylindrical specimens of unitary aspect ratios and uniform grain-size distributions were extrapolated for hydroxyapatite (HAP) to 70 MPa, 9.2 GPa, and 0.36 J cm(-3), and for tricalcium phosphate (TCP), to 315 MPa, 21 GPa, and 2.34 J cm(-3). For total volume porosities of 50%, the corresponding values were determined: for HAP, 9.3 MPa, 1.2 GPa, 0.042 J cm(-3), for TCP, 13 MPa, 1.6 GP, 0.077 J cm(-3). Porosities of HAP specimens ranged from 3%-50%; TCP from 10%-70%. Two pore-size distributions were employed. Exponential dependencies of the mechanical properties were found upon porosity (p < 0.0001). No differences in measured mechanical properties, as determined in compression, could be attributed to pore size. The superiority of TCP increases with density and suggests that a larger or more selective pore-size distribution could be effectively employed in TCP biological implants. This work also suggests the dominant role of secondary calcium phosphates in increasing compressive strengths.
TL;DR: Ozone applications in the food industry are mostly related to decontamination of product surface and water treatment and mixed success to inactivate contaminant microflora on meat, poultry, eggs, fish, fruits, vegetables, and dry foods.
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TL;DR: In this article, the authors developed a descriptive theory of choice using anticipated emotions, where people are assumed to anticipate how they will feel about the outcomes of decisions and use their predictions to guide choice.
Abstract: In this article the authors develop a descriptive theory of choice using anticipated emotions. People are assumed to anticipate how they will feel about the outcomes of decisions and use their predictions to guide choice. The authors measure the pleasure associated with monetary outcomes of gambles and offer an account of judged pleasure called decision affect theory. Then they propose a theory of choices between gambles based on anticipated pleasure. People are assumed to choose the option with greater subjective expected pleasure. Similarities and differences between subjective expected pleasure theory and subjective expected utility theory are discussed. Emotions have powerful effects on choice. Our actual feelings of happiness, sadness, and anger both color and shape our decisions. In addition, our imagined feelings of
TL;DR: There are many differences between men and women in their susceptibility to particular autoimmune diseases, the characteristics of the disease at onset, and disease severity as mentioned in this paper, and they discuss priorities for future research.
Abstract: There are many differences between men and women in their susceptibility to particular autoimmune diseases, the characteristics of the disease at onset, and disease severity. In a Perspective in this issue, Caroline Whitacre and her fellow members of the Task Force on Gender, Multiple Sclerosis and Autoimmunity explain what we currently know about gender differences in autoimmunity and discuss priorities for future research.
TL;DR: The extant genetic and phenotypic heterogeneity in CRC leads to the conclusion that it is no longer appropriate to discuss the genetics of CRC without defining the specific hereditary CRC syndrome of concern, and a detailed differential diagnosis of the several hereditary CRC variants is provided.
Abstract: Familial colorectal cancer (CRC) is a major public health problem by virtue of its relatively high frequency. Some 15-20% of all CRCs are familial. Among these, familial adenomatous polyposis (FAP), caused by germline mutations in the APC gene, accounts for less than 1%. Hereditary non-polyposis colorectal cancer (HNPCC), also called Lynch syndrome, accounts for approximately 5-8% of all CRC patients. Among these, some 3% are mutation positive, that is, caused by germline mutations in the DNA mismatch repair genes that have so far been implicated (MLH1, MSH2, MSH6, PMS1, and PMS2). Most of the remaining patients belonging to HNPCC or HNPCC-like families are still molecularly unexplained. Among the remaining familial CRCs, a large proportion is probably caused by gene mutations and polymorphisms of low penetrance, of which the I1307K polymorphism in the APC gene is a prime example. Molecular genetic findings have enabled hereditary CRC to be divided into two groups: (1) tumours that show microsatellite instability (MSI), occur more frequently in the right colon, have diploid DNA, harbour characteristic mutations such as transforming growth factor ‚ type II receptor and BAX, and behave indolently, of which HNPCC is an example; and (2) tumours with chromosomal instability (CIN), which tend to be left sided, show aneuploid DNA, harbour characteristic mutations such as K-ras, APC, and p53, and behave aggressively, of which FAP is an example. This review focuses most heavily on the clinical features, pathology, molecular genetics, surveillance, and management including prophylactic surgery in HNPCC. Because of the diYculty in diagnosing HNPCC, a detailed diVerential diagnosis of the several hereditary CRC variants is provided. The extant genetic and phenotypic heterogeneity in CRC leads to the conclusion that it is no longer appropriate to discuss the genetics of CRC without defining the specific hereditary CRC syndrome of concern. Therefore, it is important to ascertain cancer of all anatomical sites, as well as non-cancer phenotypic stigmata (such as the perioral and mucosal pigmentations in PeutzJeghers syndrome), when taking a family cancer history. (J Med Genet 1999;36:801‐818)