Showing papers by "Cornell University published in 1994"
21 Jun 1994
TL;DR: A feature selection criterion that is optimal by construction because it is based on how the tracker works, and a feature monitoring method that can detect occlusions, disocclusions, and features that do not correspond to points in the world are proposed.
Abstract: No feature-based vision system can work unless good features can be identified and tracked from frame to frame. Although tracking itself is by and large a solved problem, selecting features that can be tracked well and correspond to physical points in the world is still hard. We propose a feature selection criterion that is optimal by construction because it is based on how the tracker works, and a feature monitoring method that can detect occlusions, disocclusions, and features that do not correspond to points in the world. These methods are based on a new tracking algorithm that extends previous Newton-Raphson style search methods to work under affine image transformations. We test performance with several simulations and experiments. >
8,432 citations
TL;DR: The estimated relative risk of death from an increase of one in the comorbidity score proved approximately equal to that from an additional decade of age.
5,388 citations
Tohoku University1, University of Zurich2, Lawrence Berkeley National Laboratory3, Stanford University4, College of William & Mary5, University of Urbino6, CERN7, Budker Institute of Nuclear Physics8, University of California, Irvine9, Cornell University10, Argonne National Laboratory11, ETH Zurich12, Tata Institute of Fundamental Research13, Hillsdale College14, Spanish National Research Council15, Ohio State University16, University of Notre Dame17, Kent State University18, University of California, San Diego19, University of California, Berkeley20, University of Minnesota21, University of Alabama22, University of Helsinki23, Los Alamos National Laboratory24, California Institute of Technology25, George Washington University26, Syracuse University27, Lawrence Livermore National Laboratory28, Oklahoma State University–Stillwater29, University of Washington30, Max Planck Society31, Boston University32, University of California, Los Angeles33, Royal Holloway, University of London34, Université Paris-Saclay35, University of Pennsylvania36, University of Illinois at Urbana–Champaign37, University of Bristol38, University of Tokyo39, University of Delaware40, Carnegie Mellon University41, University of California, Santa Cruz42, Karlsruhe Institute of Technology43, Heidelberg University44, Florida State University45, University of Mainz46, University of Edinburgh47, Brookhaven National Laboratory48, Durham University49, University of Lausanne50, Massachusetts Institute of Technology51, University of Southampton52, Nagoya University53, University of Oxford54, Northwestern University55, University of British Columbia56, Columbia University57, Lund University58, University of Sheffield59, University of California, Santa Barbara60, Iowa State University61, University of Alberta62, University of Cambridge63
TL;DR: This biennial Review summarizes much of Particle Physics using data from previous editions, plus 2205 new measurements from 667 papers, and features expanded coverage of CP violation in B mesons and of neutrino oscillations.
Abstract: This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations. For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review). Another new review is on Grand Unified Theories. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.
5,143 citations
TL;DR: An empirical method is described, based on the concept of a permutation test, for estimating threshold values that are tailored to the experimental data at hand, and is demonstrated using two real data sets derived from F(2) and recombinant inbred plant populations.
Abstract: The detection of genes that control quantitative characters is a problem of great interest to the genetic mapping community. Methods for locating these quantitative trait loci (QTL) relative to maps of genetic markers are now widely used. This paper addresses an issue common to all QTL mapping methods, that of determining an appropriate threshold value for declaring significant QTL effects. An empirical method is described, based on the concept of a permutation test, for estimating threshold values that are tailored to the experimental data at hand. The method is demonstrated using two real data sets derived from F(2) and recombinant inbred plant populations. An example using simulated data from a backcross design illustrates the effect of marker density on threshold values.
4,964 citations
Book•
01 Jan 1994TL;DR: The history of contention in social movements can be traced to the birth of the modern social movement as discussed by the authors, and the dynamics of social movements have been studied in the context of contention.
Abstract: Introduction 1 Contentious politics and social movements: Part I The Birth of the Modern Social Movement: 2 Modular collective action 3 Print and association 4 Statebuilding and social movements Part II From Contention to Social Movements: 5 Political opportunities and constraints 6 The repertoire of contention 7 Framing contention 8 Mobilising structures and contentious politics Part III The Dynamics of Movement: 9 Cycles of contention 10 Struggling to reform 11 Transnational contention/conclusion: the future of social movements
3,676 citations
TL;DR: The next ten years will bring forth evidence that NO is produced in slime molds, locusts, beetles, horseshoe crabs, mollusks, chickens, mice, rats, cows, and humans, and its physiologic roles will be at least as protean as those discovered for corticosteroids in the 194Os- 1980s.
2,917 citations
TL;DR: How the marine luminescent bacterium V. fischeri uses the LuxR and LuxI proteins for intercellular communication is reviewed and a newly discovered family of LuxRand LuxI homologs in diverse bacterial species is described.
Abstract: It has long been appreciated that certain groups of bacteria exhibit cooperative behavioral patterns. For example, feeding and sporulation of both myxobacteria and actinomycetes seem optimized for large populations of cells behaving almost as a single multicellular organism. The swarming motility of microorganisms such as Vibrio parahaemolyticus and Proteus mirabilis provides another excellent example of multicellular behavior among bacteria (2). Intercellular communication likewise has been appreciated for several years in Vibrio fischeri, Myxococcus xanthus, Bacillus subtilis, Streptomyces spp., the eukaryotic slime mold Dictyostelium discoideum, and other species (44). Here we first review how the marine luminescent bacterium V. fischeri uses the LuxR and LuxI proteins for intercellular communication and then describe a newly discovered family of LuxR and LuxI homologs in diverse bacterial species.
2,693 citations
TL;DR: The authors propose an empirically testable theoretical model that goes beyond and qualifies the established behavioral genetics paradigm by allowing for nonadditive synergistic effects, direct measures of the environment, and mechanisms of organism-environment interaction through which genotypes are transformed into phenotypes.
Abstract: In response to Anastasi's (1958) long-standing challenge, the authors propose an empirically testable theoretical model that (a) goes beyond and qualifies the established behavioral genetics paradigm by allowing for nonadditive synergistic effects, direct measures of the environment, and mechanisms of organism-environment interaction, called proximal processes, through which genotypes are transformed into phenotypes; (b) hypothesizes that estimates of heritability (e.g., h2) increase markedly with the magnitude of proximal processes; (c) demonstrates that heritability measures the proportion of variation in individual differences attributable only to actualized genetic potential, with the degree of nonactualized potential remaining unknown; (d) proposes that, by enhancing proximal processes and environments, it is possible to increase the extent of actualized genetic potentials for developmental competence.
2,609 citations
TL;DR: Reporter constructs containing truncated promoter regions revealed that activation of NF-kappa B/Rel is critical in the induction of iNOS by LPS, however, additional, newly synthesized proteins contribute to the NF- kappa Bd-dependent transcription factor complex on the iN OS promoter in LPS-treated mouse macrophages.
2,195 citations
2,089 citations
07 May 1994
TL;DR: A new approach to the correspondence problem that makes use of non-parametric local transforms as the basis for correlation, which can result in improved performance near object boundaries when compared with conventional methods such as normalized correlation.
Abstract: We propose a new approach to the correspondence problem that makes use of non-parametric local transforms as the basis for correlation. Non-parametric local transforms rely on the relative ordering of local intensity values, and not on the intensity values themselves. Correlation using such transforms can tolerate a significant number of outliers. This can result in improved performance near object boundaries when compared with conventional methods such as normalized correlation. We introduce two non-parametric local transforms: the rank transform, which measures local intensity, and the census transform, which summarizes local image structure. We describe some properties of these transforms, and demonstrate their utility on both synthetic and real data.
TL;DR: A review of the major bodies of empirical literature on attachment theory can be found in this article, where the authors conclude that a comprehensive theory of close relationships is both desirable and, with the integration of existing theories and concepts, currently achievable.
Abstract: Recent years have witnessed a proliferation of research on close relationships and the emergence of a new relationship subdiscipline within the social sciences. To date, the new science of relationships has been dominated by data. This article is based on the conviction that progress now hinges on the development of theory to organize and interpret extant findings and to guide future investigations. Through a selective but extensive review of the major bodies of empirical literature, we attempt to show that attachment theory can incorporate a broad range of findings on adult relationships. In addition, attachment theory addresses an impressive array of research questions concerning the functions, emotional dynamics, evolutionary origins, and developmental pathways of human affectional bonds. We conclude that a comprehensive theory of close relationships is both desirable and, with the integration of existing theories and concepts, currently achievable.
TL;DR: The identification of VHL mutations in a majority of localized and advanced sporadic renal carcinomas and in a second form of hereditary renal carcinoma indicates that the VHL gene plays a critical part in the origin of this malignancy.
Abstract: Multiple, bilateral renal carcinomas are a frequent occurrence in von Hippel-Lindau (VHL) disease. To elucidate the aetiological role of the VHL gene in human kidney tumorigenesis, localized and advanced tumours from 110 patients with sporadic renal carcinoma were analysed for VHL mutations and loss of heterozygosity (LOH). VHL mutations were identified in 57% of clear cell renal carcinomas analysed and LOH was observed in 98% of those samples. Moreover, VHL was mutated and lost in a renal tumour from a patient with familial renal carcinoma carrying the constitutional translocation, t(3;8)(p14;q24). The identification of VHL mutations in a majority of localized and advanced sporadic renal carcinomas and in a second form of hereditary renal carcinoma indicates that the VHL gene plays a critical part in the origin of this malignancy.
TL;DR: A phylogenetic hypothesis based on mitochondrial DNA sequences for 14 divergent races of Heliconius erato reveals that similar wing patterns have evolved rapidly and convergently within the species, suggesting a simultaneous radiation of races within the last 200,000 years.
Abstract: The neotropical Heliconius butterflies are famous examples of Mullerian mimicry, due to the diverse array of shared, brightly colored wing patterns that advertise the butterflies' unpalatability. The parallel geographical variation in these patterns within several widespread species has been invoked to support the controversial Pleistocene refugium hypothesis of tropical diversification. However, in no Heliconius species have either evolutionary rates or relationships among geographical races been explicitly examined. I present a phylogenetic hypothesis based on mitochondrial DNA sequences for 14 divergent races of Heliconius erato, which reveals that similar wing patterns have evolved rapidly and convergently within the species. There is a basal split between groups of races from east and west of the Andes, reflecting a vicariant separation at the base of the Pleistocene. Within each of these clades, sequence divergence is very low, and some haplotypes are shared between allopatric races with radically different wing patterns. The topology implies a simultaneous radiation of races in these two areas within the last 200,000 years. Ages for the clades are estimated by comparing sequence divergence to a plot of mitochondrial divergence in several arthropod taxa with independently dated divergence times. This plot is linear and suggests that mitochondrial DNA in arthropods evolves in a clocklike manner, at least initially, when sequence divergence is low.
TL;DR: The interaction of polymers with their environment depends largely on the functional groups they carry and the placement of functional groups at polymer chain ends or in well-defined segments can determine the ultimate properties.
Abstract: The interaction of polymers with their environment depends largely on the functional groups they carry. Interfaces between different polymers or between polymers and other surfaces can be strengthened through the design of molecular interactions such as hydrogen bonding and through the control of polymer architecture. The placement of functional groups at polymer chain ends or in well-defined segments can determine the ultimate properties. Three-dimensional synthetic polymers such as dendrimers can be fashioned to encapsulate reactive sites or provide highly controlled surfaces and interfaces.
TL;DR: This paper establishes that the interior-reflective Newton approach is globally and quadratically convergent, and develops a specific example of interior- reflective Newton methods which can be used for large-scale and sparse problems.
Abstract: We consider a new algorithm, an interior-reflective Newton approach, for the problem of minimizing a smooth nonlinear function of many variables, subject to upper and/or lower bounds on some of the variables. This approach generatesstrictly feasible iterates by using a new affine scaling transformation and following piecewise linear paths (reflection paths). The interior-reflective approach does not require identification of an "activity set". In this paper we establish that the interior-reflective Newton approach is globally and quadratically convergent. Moreover, we develop a specific example of interior-reflective Newton methods which can be used for large-scale and sparse problems.
TL;DR: This article investigated the effects of corrective procedures on language learning and found that corrective moves by teachers or other caretakers are ineffective in correcting learner errors in a learner's own right.
Abstract: enties, with the ground breaking publications of Pit Corder, Burt and Kiparsky, George, and Richards (14), one of the central themes of second language research has been the study of learner errors as a reflection of hypothesis testing on the part of second language learners (8; 15; 20; 23;)1 Eventually, the attention of those working on learner errors has moved away from the analysis of errors in their own right as indications of hypothesis testing and interlanguage development to concern with questions relating to the potential effects of corrective procedures on language learning The fundamental question is: does error correction lead to learning, or are corrective moves by teachers or other caretakers ineffective? In addition, some corollary questions have also been addressed, including how and when errors should be corrected (7: p 135) Research aimed at answering these questions has been carried out in either an ethnographic or an experimental framework2 Those working within the ethnographic approach have conducted careful observational studies of corrective behaviors both in the classroom and natu-
TL;DR: Astrocytes are shown to directly modulate the free cytosolic calcium, and hence transmission characteristics, of neighboring neurons, which suggests that the astrocytic-neuronal signaling is mediated through intercellular connections rather than synaptically.
Abstract: Although astrocytes have been considered to be supportive, rather than transmissive, in the adult nervous system, recent studies have challenged this assumption by demonstrating that astrocytes possess functional neurotransmitter receptors. Astrocytes are now shown to directly modulate the free cytosolic calcium, and hence transmission characteristics, of neighboring neurons. When a focal electric field potential was applied to single astrocytes in mixed cultures of rat forebrain astrocytes and neurons, a prompt elevation of calcium occurred in the target cell. This in turn triggered a wave of calcium increase, which propagated from astrocyte to astrocyte. Neurons resting on these astrocytes responded with large increases in their concentration of cytosolic calcium. The gap junction blocker octanol attenuated the neuronal response, which suggests that the astrocytic-neuronal signaling is mediated through intercellular connections rather than synaptically. This neuronal response to local astrocytic stimulation may mediate local intercellular communication within the brain.
TL;DR: It is shown that the expressiveness of the timed μ-calculus is incomparable to theexpressiveness of timed CTL, which does not impair the symbolic verification of "implementable" real-time programs-those whose safety constraints are machine-closed with respect to diverging time and whose fairness constraints are restricted to finite upper bounds on clock values.
Abstract: We describe finite-state programs over real-numbered time in a guarded-command language with real-valued clocks or, equivalently, as finite automata with real-valued clocks. Model checking answers the question which states of a real-time program satisfy a branching-time specification (given in an extension of CTL with clock variables). We develop an algorithm that computes this set of states symbolically as a fixpoint of a functional on state predicates, without constructing the state space. For this purpose, we introduce a μ-calculus on computation trees over real-numbered time. Unfortunately, many standard program properties, such as response for all nonzeno execution sequences (during which time diverges), cannot be characterized by fixpoints: we show that the expressiveness of the timed μ-calculus is incomparable to the expressiveness of timed CTL. Fortunately, this result does not impair the symbolic verification of "implementable" real-time programs-those whose safety constraints are machine-closed with respect to diverging time and whose fairness constraints are restricted to finite upper bounds on clock values. All timed CTL properties of such programs are shown to be computable as finitely approximable fixpoints in a simple decidable theory.
TL;DR: It is proposed that compact coding schemes are insufficient to account for the receptive field properties of cells in the mammalian visual pathway and suggested that natural scenes, to a first approximation, can be considered as a sum of self-similar local functions (the inverse of a wavelet).
Abstract: A number of recent attempts have been made to describe early sensory coding in terms of a general information processing strategy. In this paper, two strategies are contrasted. Both strategies take advantage of the redundancy in the environment to produce more effective representations. The first is described as a "compact" coding scheme. A compact code performs a transform that allows the input to be represented with a reduced number of vectors (cells) with minimal RMS error. This approach has recently become popular in the neural network literature and is related to a process called Principal Components Analysis (PCA). A number of recent papers have suggested that the optimal compact code for representing natural scenes will have units with receptive field profiles much like those found in the retina and primary visual cortex. However, in this paper, it is proposed that compact coding schemes are insufficient to account for the receptive field properties of cells in the mammalian visual pathway. In contrast, it is proposed that the visual system is near to optimal in representing natural scenes only if optimality is defined in terms of "sparse distributed" coding. In a sparse distributed code, all cells in the code have an equal response probability across the class of images but have a low response probability for any single image. In such a code, the dimensionality is not reduced. Rather, the redundancy of the input is transformed into the redundancy of the firing pattern of cells. It is proposed that the signature for a sparse code is found in the fourth moment of the response distribution (i.e., the kurtosis). In measurements with 55 calibrated natural scenes, the kurtosis was found to peak when the bandwidths of the visual code matched those of cells in the mammalian visual cortex. Codes resembling "wavelet transforms" are proposed to be effective because the response histograms of such codes are sparse (i.e., show high kurtosis) when presented with natural scenes. It is proposed that the structure of the image that allows sparse coding is found in the phase spectrum of the image. It is suggested that natural scenes, to a first approximation, can be considered as a sum of self-similar local functions (the inverse of a wavelet). Possible reasons for why sensory systems would evolve toward sparse coding are presented.
TL;DR: In this article, the authors explored the combined use of subjective and objective performance measures in implicit and explicit incentive contracts, and showed that if objective measures are sufficiently close to perfect then no implicit contracts are feasible.
Abstract: Objective measures of performance are seldom perfect. In response, incentive contracts often include important subjective components that mitigate incentive distortions caused by imperfect objective measures. This paper explores the combined use of subjective and objective performance measures in (respectively) implicit and explicit incentive contracts. Naturally, objective and subjective measures often are substitutes, sometimes strikingly so: we show that if objective measures are sufficiently close to perfect then no implicit contracts are feasible (because the firm’s fallback position after reneging on an implicit contract is too attractive). We also show, however, that objective and subjective measures can reinforce each other: if objective measures become more accurate then in some circumstances the optimal contract puts more weight on subjective measures (because the improved objective measures increase the value of the ongoing relationship, and so reduce the firm’s incentive to renege). We also analyze the use of subjective weights on objective performance measures, and provide case-study evidence consistent with our analyses.
TL;DR: It is possible to assess personality disorders with reasonably good reliability in different nations, languages, and cultures using a semistructured clinical interview that experienced clinicians find relevant, meaningful, and user-friendly.
Abstract: Background: One of the aims of the World Health Organization/Alcohol, Drug Abuse, and Mental Health Administration joint program on psychiatric diagnosis and classification is the development and standardization of diagnostic assessment instruments for use in clinical research worldwide. The International Personality Disorder Examination (IPDE) is a semistructured clinical interview compatible with the International Classification of Diseases, Tenth Revision , and the DMS-III-R classification systems. This is the first report of the results of a field trial to investigate the feasibility of using the IPDE to assess personality disorders worldwide. Methods: The IPDE was administered by 58 psychiatrists and clinical psychologists to 716 patients enrolled in clinical facilities at 14 participating centers in 11 countries in North America, Europe, Africa, and Asia. To determine interrater reliability, 141 of the IPDEs (20%) were independently rated by a silent observer. To determine temporal stability, 243 patients (34%) were reexamined after an average interval of 6 months. Results: The IPDE proved acceptable to clinicians and demonstrated an interrater reliability and temporal stability roughly similar to instruments used to diagnose the psychoses, mood, anxiety, and substance use disorders. Conclusion: It is possible to assess personality disorders with reasonably good reliability in different nations, languages, and cultures using a semistructured clinical interview that experienced clinicians find relevant, meaningful, and user-friendly.
TL;DR: This method, based on that of Doyle and Doyle (1990), is a CTBA-based extraction procedure modified by the use of NaCl to remove polysaccharides and PVP to eliminate polyphenols during DNA purification.
Abstract: A quick, simple, and reliable method for the extraction of DNA from grapevine species, hybrids, andAmpelopsis brevipedunculata (Vitaceae) has been developed. This method, based on that of Doyle and Doyle (1990), is a CTBA-based extraction procedure modified by the use of NaCl to remove polysaccharides and PVP to eliminate polyphenols during DNA purification. The method has also been used successfully for extraction of total DNA from other fruit species such as apple (Malus domestica), apricot (Prunus armeniaca), cherry (Prunus avium), peach (Prunus persica), plum (Prunus domestica), and raspberry (Rubus idaeus). DNA yield from this procedure is high (up to 1 mg/g of leaf tissue). DNA is completely digestible with restriction endonucleases and amplifiable in the polymerase chain reaction (PCR), indicating freedom from common contaminating compounds.
TL;DR: This, to the authors' knowledge, is the second example, besides the thrombin receptor, of a proteolytically activated seven-transmembrane G-protein-coupled receptor, and is provisionally named proteinase activated receptor 2.
Abstract: A DNA sequence encoding a G-protein-coupled receptor was isolated from a mouse genomic library. The predicted protein is similar in structure to the thrombin receptor and has a similar activation mechanism. When expressed in Xenopus laevis oocytes, the receptor was activated by low concentrations of trypsin (EC 3.4.21.4) and by a peptide (SLIGRL) derived from the receptor sequence, but was not activated by thrombin (EC 3.4.21.5). Trypsin failed to activate a mutant receptor in which the presumed cleavage site Arg-34-Ser-35 was changed to an Arg-Pro sequence. The agonist peptide (SLIGRL) activated equally well mutant and wild-type receptors. Northern blot analysis demonstrated receptor transcripts in highly vascularized tissues such as kidney, small intestine, and stomach. Because this, to our knowledge, is the second example, besides the thrombin receptor, of a proteolytically activated seven-transmembrane G-protein-coupled receptor, we have provisionally named it proteinase activated receptor 2.
01 Aug 1994
TL;DR: A series of information retrieval experiments was carried out with a computer installed in a medical practice setting for relatively inexperienced physician end-users using a commercial MEDLINE product based on the vector space model, finding that these physicians searched just as effectively as more experienced searchers using Boolean searching.
Abstract: A series of information retrieval experiments was carried out with a computer installed in a medical practice setting for relatively inexperienced physician end-users. Using a commercial MEDLINE product based on the vector space model, these physicians searched just as effectively as more experienced searchers using Boolean searching. The results of this experiment were subsequently used to create a new large medical test collection, which was used in experiments with the SMART retrieval system to obtain baseline performance data as well as compare SMART with the other searchers.
TL;DR: A molecular map has been constructed for the rice genome comprised of 726 markers (mainly restriction fragment length polymorphisms; RFLPs) derived from a backcross between cultivated rice and its wild African relative, Oryza longistaminata.
Abstract: A molecular map has been constructed for the rice genome comprised of 726 markers (mainly restriction fragment length polymorphisms; RFLPs). The mapping population was derived from a backcross between cultivated rice, Oryza sativa, and its wild African relative, Oryza longistaminata. The very high level of polymorphism between these species, combined with the use of polymerase chain reaction-amplified cDNA libraries, contributed to mapping efficiency. A subset of the probes used in this study was previously used to construct an RFLP map derived from an inter subspecific cross, providing a basis for comparison of the two maps and of the relative mapping efficiencies in the two crosses. In addition to the previously described PstI genomic rice library, three cDNA libraries from rice (Oryza), oat (Avena) and barley (Hordeum) were used in this mapping project. Levels of polymorphism detected by each and the frequency of identifying heterologous sequences for use in rice mapping are discussed. Though strong reproductive barriers isolate O. sativa from O. longistaminata, the percentage of markers showing distorted segregation in this backcross population was not significantly different than that observed in an intraspecific F2 population previously used for mapping. The map contains 1491 cM with an average interval size of 4.0 cM on the framework map, and 2.0 cM overall. A total of 238 markers from the previously described PstI genomic rice library, 250 markers from a cDNA library of rice (Oryza), 112 cDNA markers from oat (Avena), and 20 cDNA markers from a barley (Hordeum) library, two genomic clones from maize (Zea), 11 microsatellite markers, three telomere markers, eleven isozymes, 26 cloned genes, six RAPD, and 47 mutant phenotypes were used in this mapping project. Applications of a molecular map for plant improvement are discussed.
TL;DR: This paper found that measures of how much a student's teacher knows about what he or she is teaching has a positive effect on pupils' learning gains. But the evidence also suggests that the effects of subject matter preparation diminish with time and vary across types of students.
TL;DR: A useful approach to understanding the functions of a cellular component such as GSH is to remove it and to determine the consequences of its deletion.
TL;DR: The authors show that in markets where investors know a priori that they do not have to compete with informed investors, IPOs are not underpriced and also show that IPOs underwritten by reputable investment banks experience significantly less underpricing and perform significantly better in the long run.
Abstract: We test the empirical implications of several models of IPO underpricng. Consistent with the winner’s-curse hypothesis, we show that in markets where investors know a priori that they do not have to compete with informed investors, IPOs are not underpriced. We also show that IPOs underwritten by reputable investment banks experience significantly less underpricing and perform significantly better in the long run. We do not find empirical support for the signaling models that try to explain why firms underprice. In fact, we find that (1) firms that underprice more return to the reissue market less frequently, and for lesser amounts, than firms that underprice less, and (2) firms that underprice less experience higher earnings and pay higher dividends, contrary to the models’ predictions.