Showing papers by "Ohio State University published in 1997"
TL;DR: Empirical and conceptual developments over the past four years on attitudes and persuasion are reviewed, with particular attention paid to work on attitude accessibility, ambivalence, and the affective versus cognitive bases of attitudes.
Abstract: ▪ Abstract We review empirical and conceptual developments over the past four years (1992–1995) on attitudes and persuasion. A voluminous amount of material was produced concerning attitude structure, attitude change, and the consequences of holding attitudes. In the structure area, particular attention is paid to work on attitude accessiblity, ambivalence, and the affective versus cognitive bases of attitudes. In persuasion, our review examines research that has focused on high effort cognitive processes (central route), low effort processes (peripheral route), and the multiple roles by which variables can have an impact on attitudes. Special emphasis is given to work on cognitive dissonance and other biases in message processing, and on the multiple processes by which mood influences evaluations. Work on the consequences of attitudes focuses on the impact of attitudes on behavior and social judgments.
3,365 citations
TL;DR: In this article, the authors examined the physiological origins and mechanisms of heart rate variability, considered quantitative approaches to measurement, and highlighted important caveats in the interpretation of heart rates variability, and outlined guidelines for research in this area.
Abstract: Components of heart rate variability have attracted considerable attention in psychology and medicine and have become important dependent measures in psychophysiology and behavioral medicine. Quantification and interpretation of heart rate variability, however, remain complex issues and are fraught with pitfalls. The present report (a) examines the physiological origins and mechanisms of heart rate variability, (b) considers quantitative approaches to measurement, and (c) highlights important caveats in the interpretation of heart rate variability. Summary guidelines for research in this area are outlined, and suggestions and prospects for future developments are considered.
3,273 citations
TL;DR: In this paper, a conceptual model that provides guidance for future supply chain decision-making and research is proposed, based on a review of the literature and management practice, it is clear that there is a need for some level of coordination of activities and processes within and between organizations in the supply chain that extends beyond logistics.
Abstract: Practitioners and educators have variously addressed the concept of supply chain management (SCM) as an extension of logistics, the same as logistics, or as an all‐encompassing approach to business integration. Based on a review of the literature and management practice, it is clear that there is a need for some level of coordination of activities and processes within and between organizations in the supply chain that extends beyond logistics. We believe that this is what should be called SCM. This article proposes a conceptual model that provides guidance for future supply chain decision‐making and research.
2,789 citations
TL;DR: In this article, an option pricing model that allows volatility, interest rates and jumps to be stochastic is presented. But it is not known whether and by how much each generalization improves option pricing and hedging.
Abstract: Substantial progress has been made in developing more realistic option pricing models. Empirically, however, it is not known whether and by how much each generalization improves option pricing and hedging. We fill this gap by first deriving an option model that allows volatility, interest rates and jumps to be stochastic. Using S&P 500 options, we examine several alternative models from three perspectives: (1) internal consistency of implied parameters/volatility with relevant timeseries data, (2) out-of-sample pricing, and (3) hedging. Overall, incorporating stochastic volatility and jumps is important for pricing and internal consistency. But for hedging, modeling stochastic volatility alone yields the best performance. IN THE LAST TWO DECADES, option pricing has witnessed an explosion of new
2,777 citations
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TL;DR: The authors examined the determinants and implications of holdings of cash and marketable securities by publicly traded U.S. firms in the 1971-1994 period and found that firms with strong growth opportunities and riskier cash flows hold relatively high ratios of cash to total assets.
Abstract: We examine the determinants and implications of holdings of cash and marketable" securities by publicly traded U.S. firms in the 1971-1994 period. Firms with strong growth" opportunities and riskier cash flows hold relatively high ratios of cash to total assets. Firms" that have the greatest access to the capital markets (e.g. large firms and those with credit" ratings) tend to hold lower ratios of cash to total assets. These results are consistent with the" view that firms hold liquid assets to ensure that they will be able to keep investing when cash" flow is too low relative to planned investment and when outside funds are expensive. The" short run impact of excess cash on capital expenditures, acquisition spending and payouts to" shareholders is small. The main reason that firms experience large changes in excess cash is" the occurrence of operating losses. There is no evidence that risk management and cash" holdings are substitutes.
2,581 citations
TL;DR: The authors examined differences between entrepreneurs and managers in large organizations with respect to two biases and heuristics: overconfidence (overestimating the probability of being right) and representativeness (the tendency to overgeneralize from a few characteristics or observations).
2,505 citations
TL;DR: In this paper, a model of relationship maintenance is developed and propositions are presented regarding the antecedents and consequences of customers' relationship maintenance, and theoretical and practical implications of the paper are discussed.
1,637 citations
TL;DR: A refined hypothesis of species phylogeny of section Paeonia was proposed by considering the discordance between the nuclear and cpDNA phylogenies to be results of hybrid speciation followed by inheritance of cpDNA of one parent and fixation of ITS sequences of another parent.
Abstract: The coding region of the mat K gene and two intergenic spacers, psb A-trn H and trn L(UAA)-trn F(GAA), of cpDNA were sequenced to study phylogenetic relationships of 32 Paeonia species. In the psb A-trn H intergenic spacer, short sequences bordered by long inverted repeats have undergone inversions that are often homoplasious mutations. Insertions/deletions found in the two intergenic spacers, mostly resulting from slipped-strand mispairing, provided relatively reliable phylogenetic information. The mat K coding region, evolving more rapidly than the trnL-trn F spacer and more slowly than the psb A-trn H spacer, produced the best resolved phylogenetic tree. The mat K phylogeny was compared with the phylogeny obtained from sequences of internal transcribed spacers (ITS) of nuclear ribosomal DNA. A refined hypothesis of species phylogeny of section Paeonia was proposed by considering the discordance between the nuclear and cpDNA phylogenies to be results of hybrid speciation followed by inheritance of cpDNA of one parent and fixation of ITS sequences of another parent. The Eurasian and western North American disjunct distribution of the genus may have resulted from interrruption of the continuous distribution of ancestral populations of extant peony species across the Bering land bridge during the Miocene. Pleistocene glaciation may have played an important role in triggering extensive reticulate evolution within section Paeonia and shifting distributional ranges of both parental and hybrid species.
1,422 citations
TL;DR: This paper examined how local television news outlets framed a specific, dramatic event: a demonstration and rally by the Ku Klux Klan (KKK) in a small Ohio city, and explored the effect of alternative news frames for this event on tolerance for KKK activities.
Abstract: public controversy. In the present research, we examine how local television news outlets framed a specific, dramatic event: a demonstration and rally by the Ku Klux Klan (KKK) in a small Ohio city. We explore the effect of alternative news frames for this event on tolerance for KKK activities. We also test contrasting hypotheses about how viewers psychologically process news frames, and how such frames ultimately affect viewers' thoughts about political controversies.
1,322 citations
TL;DR: Both secondary degeneration at the site of SCI and the chronic demyelination of tracts away from the injury appear to be due in part to apoptosis, and as cytokines have been shown to mediate oligodendrocyte death in vitro, it seems likely that chronic demYelination after CNS injury shares features with chronic degenerative disorders like multiple sclerosis.
Abstract: Apoptosis is a morphologically defined form of programmed cell death seen in a variety of circumstances, including immune cell selection, carcinogenesis and development. Apoptosis has very recently been seen after ischemic or traumatic injury to the central nervous system (CNS), suggesting that active cell death as well as passive necrosis may mediate damage after CNS injury. After spinal cord injury (SCI) in the rat, typical post-traumatic necrosis occurred, but in addition, apoptotic cells were found from 6 hours to 3 weeks after injury, especially in the spinal white matter. Apoptotic cells were positive for oligodendrocyte markers. After SCI in monkeys, apoptotic cells were found within remote degenerating fiber tracts. Both secondary degeneration at the site of SCI and the chronic demyelination of tracts away from the injury appear to be due in part to apoptosis. As cytokines have been shown to mediate oligodendrocyte death in vitro, it seems likely that chronic demyelination after CNS injury shares features with chronic degenerative disorders like multiple sclerosis.
1,166 citations
TL;DR: Evidence is reviewed showing that the positive and negative evaluative processes underlying many attitudes are distinguishable, are characterized by distinct activation functions, are related differentially to attitude ambivalence, have distinguishable antecedents, and tend to gravitate from a bivariate toward a bipolar structure when the underlying beliefs are the target of deliberation or a guide for behavior.
Abstract: All organisms must be capable of differentiating hostile from hospitable stimuli to survive. Typically, this evaluative discrimination is conceptualized as being bipolar (hostile-hospitable). This conceptualization is certainly evident in the area of attitudes, where the ubiquitous bipolar attitude measure, by gauging the net affective predisposition toward a stimulus, treats positive and negative evaluative processes as equivalent, reciprocally activated, and interchangeable. Contrary to conceptualizations of this evaluative process as bipolar, recent evidence suggests that distinguishable motivational systems underlie assessments of the positive and negative significance of a stimulus. Thus, a stimulus may vary in terms of the strength of positive evaluative activation and the strength of negative evaluative activation it evokes. Low activation of positive and negative evaluative processes by a stimulus reflects attitude neutrality or indifference, whereas high activation of positive and negative evaluative processes reflects attitude ambivalence. As such, attitudes can be represented more completely within a bivariate space than along a bipolar continuum. Evidence is reviewed showing that the positive and negative evaluative processes underlying many attitudes are distinguishable (stochastically and functionally independent), are characterized by distinct activation functions (positivity offset and negativity bias principles), are related differentially to attitude ambivalence (corollary of ambivalence asymmetries), have distinguishable antecedents (heteroscedacity principle), and tend to gravitate from a bivariate toward a bipolar structure when the underlying beliefs are the target of deliberation or a guide for behavior (principle of motivational certainty). The implications for society phenomena such as political elections and democratic structures are discussed.
TL;DR: The chemical interactions of hydrophobic organic contaminants (HOCs) with soils and sediments (geosorbents) may result in strong binding and slow subsequent release rates that significantly affect remediation rates and endpoints.
Abstract: The chemical interactions of hydrophobic organic contaminants (HOCs) with soils and sediments (geosorbents) may result in strong binding and slow subsequent release rates that significantly affect remediation rates and endpoints The underlying physical and chemical phenomena potentially responsible for this apparent sequestration of HOCs by geosorbents are not well understood This challenges our concepts for assessing exposure and toxicity and for setting environmental quality criteria Currently there are no direct observational data revealing the molecular-scale locations in which nonpolar organic compounds accumulate when associated with natural soils or sediments Hence macroscopic observations are used to make inferences about sorption mechanisms and the chemical factors affecting the sequestration of HOCs by geosorbents Recent observations suggest that HOC interactions with geosorbents comprise different inorganic and organic surfaces and matrices, and distinctions may be drawn along these lines,
TL;DR: An ice core record from the Guliya ice cap on the Qinghai-Tibetan Plateau provides evidence of regional climatic conditions over the last glacial cycle as discussed by the authors.
Abstract: An ice core record from the Guliya ice cap on the Qinghai-Tibetan Plateau provides evidence of regional climatic conditions over the last glacial cycle. 36 Cl data suggest that the deepest 20 meters of the core may be more than 500,000 years old. The δ 18 O change across Termination I is ∼5.4 per mil, similar to that in the Huascaran (Peru) and polar ice cores. Three Guliya interstadials (Stages 3, 5a, and 5c) are marked by increases in δ 18 O values similar to that of the Holocene and Eemian (∼124,000 years ago). The similarity of this pattern to that of CH 4 records from polar ice cores indicates that global CH 4 levels and the tropical hydrological cycle are linked. The Late Glacial Stage record contains numerous 200-year oscillations in δ 18 O values and in dust, NH 4 + , and NO 3 − levels.
TL;DR: Honeybees are used to demonstrate that odour encoding involves, as it does in locusts, the oscillatory synchronization of assemblies of projection neurons and that this synchronization is also selectively abolished by picrotoxin, an antagonist of the GABAA (γ-aminobutyric acid) receptor.
Abstract: Stimulus-evoked oscillatory synchronization of neural assemblies has been described in the olfactory and visual systems of several vertebrates and invertebrates In locusts, information about odour identity is contained in the timing of action potentials in an oscillatory population response, suggesting that oscillations may reflect a common reference for messages encoded in time Although the stimulus-evoked oscillatory phenomenon is reliable, its roles in sensation, perception, memory formation and pattern recognition remain to be demonstrated--a task requiring a behavioural paradigm Using honeybees, we now demonstrate that odour encoding involves, as it does in locusts, the oscillatory synchronization of assemblies of projection neurons and that this synchronization is also selectively abolished by picrotoxin, an antagonist of the GABA(A) (gamma-aminobutyric acid) receptor By using a behavioural learning paradigm, we show that picrotoxin-induced desynchronization impairs the discrimination of molecularly similar odorants, but not that of dissimilar odorants It appears, therefore, that oscillatory synchronization of neuronal assemblies is functionally relevant, and essential for fine sensory discrimination This suggests that oscillatory synchronization and the kind of temporal encoding it affords provide an additional dimension by which the brain could segment spatially overlapping stimulus representations
TL;DR: Trauma‐induced central nervous system (CNS) inflammation, regardless of strain, occurs rapidly at the site of injury and involves the activation of resident and recruited immune cells.
Abstract: The distribution of microglia, macrophages, T-lymphocytes, and astrocytes was characterized throughout a spinal contusion lesion in Sprague-Dawley and Lewis rats by using immunohistochemistry. The morphology, spatial localization, and activation state of these inflammatory cells were described both qualitatively and quantitatively at 12 hours, 3, 7, 14, and 28 days after injury. By use of OX42 and ED1 antibodies, peak microglial activation was observed within the lesion epicenter of both rat strains between three and seven days post-injury preceding the bulk of monocyte influx and macrophage activation (seven days). Rostral and caudal to the injury site, microglial activation plateaued between two and four weeks post-injury in the dorsal and lateral funiculi as indicated by morphological transformation and the de-novo expression of major histocompatibility class II (MHC II) molecules. Similar to the timing of microglial reactions, T-lymphocytes maximally infiltrated the lesion epicenter between three and seven days post-injury. Reactive astrocytes, while present in the acute lesion, were more prominent at later survival times (7–28 days). These cells were interspersed with activated microglia but appeared to surround and enclose tissue sites occupied by reactive microglia and phagocytic macrophages. Thus, trauma-induced central nervous system (CNS) inflammation, regardless of strain, occurs rapidly at the site of injury and involves the activation of resident and recruited immune cells. In regions rostral or caudal to the epicenter, prolonged activation of inflammatory cells occurs preferentially in white matter and primarily consists of activated microglia and astrocytes.
Differences were observed in the magnitude and duration of macrophage activation between Sprague-Dawley (SD) and Lewis (LEW) rats throughout the lesion. Increased expression of complement type 3 receptors (OX42) and macrophage-activation antigens (ED1) persisted for longer times in LEW rats while expression of MHC class II molecules was attenuated in LEW compared to SD rats at all times examined. Variations in the onset and duration of T-lymphocyte infiltration also were observed between strains with twice as many T-cells present in the lesion epicenter of Lewis rats by 3 days post-injury. These strain-specific findings potentially represent differences in corticosteroid regulation of immunity and may help predict a range of functional neurologic consequences affected by neuroimmune interactions. J. Comp. Neurol. 377:443–464, 1997. © 1997 Wiley-Liss, Inc.
TL;DR: This article proposed a theory of framing effects, with a specific focus on the psychological mechanisms by which framing influences political attitudes and discussed important conceptual differences between framing and traditional theories of persuasion that focus on belief change.
Abstract: Framing is the process by which a communication source constructs and defines a social or political issue for its audience. While many observers of political communication and the mass media have discussed framing, few have explicitly described how framing affects public opinion. In this paper we offer a theory of framing effects, with a specific focus on the psychological mechanisms by which framing influences political attitudes. We discuss important conceptual differences between framing and traditional theories of persuasion that focus on belief change. We outline a set of hypotheses about the interaction between framing and audience sophistication, and test these in an experiment. The results support our argument that framing is not merely persuasion, as it is traditionally conceived. We close by reflecting on the various routes by which political communications can influence attitudes.
TL;DR: The authors provides a systematic review of the observed properties of AGN across the entire electromagnetic spectrum, examines the underlying physics, and shows how the brightest AGN, quasars, can be used to probe the farthest reaches of the Universe.
Abstract: How can we test if a supermassive black hole lies at the heart of every active galactic nucleus? What are LINERS, BL Lacs, N galaxies, broad-line radio galaxies and radio-quiet quasars and how do they compare? This timely textbook answers these questions in a clear, comprehensive and self-contained introduction to active galactic nuclei - for graduate students in astronomy and physics. The study of AGN is one of the most dynamic areas of contemporary astronomy, involving one fifth of all research astronomers. This textbook provides a systematic review of the observed properties of AGN across the entire electromagnetic spectrum, examines the underlying physics, and shows how the brightest AGN, quasars, can be used to probe the farthest reaches of the Universe. This book serves as both an entry point to the research literature and as a valuable reference for researchers in the field.
TL;DR: Experimental results show that the behavior in the Tic-Tac-Toe is determined by the directly available information in external and internal representations in terms of perceptual and cognitive biases, regardless of whether the biases are consistent with, inconsistent with, or irrelevant to the task.
University of Tennessee Health Science Center1, University of Louisville2, Pennsylvania State University3, Houston Methodist Hospital4, University of Kentucky5, Erie County Medical Center6, University of Arkansas at Little Rock7, University of Cincinnati8, University of California, Davis9, Ohio State University10, Harvard University11, St. John's Hospital12, University of California, San Diego13, Vanderbilt University14, MedStar Washington Hospital Center15, University Medical Center16, University of South Carolina17, Allegheny General Hospital18, Baylor College of Medicine19, University of Southern California20, Wright State University21, University of Western Ontario22, University of Alberta23, Gundersen Health System24, Medical College of Wisconsin25, Dartmouth College26, Boston University27, Sparrow Health System28, State University of New York Upstate Medical University29, Saint Louis University30, University of Missouri31, University of Texas Medical Branch32, University of North Carolina at Chapel Hill33, Mayo Clinic34, Carolinas Medical Center35, Cedars-Sinai Medical Center36, Rutgers University37, Henry Ford Health System38, University of Manitoba39, University of Texas Southwestern Medical Center40, University of California, San Francisco41, University of South Alabama42, University of Tennessee43
TL;DR: Although newer diagnostic techniques are being applied, at this time aortography remains the diagnostic standard; bypass techniques, which provide distal aortic perfusion, produced significantly lower paraplegia rates than the clamp and sew approach.
Abstract: Background: Blunt aortic injury is a major cause of death from blunt trauma. Evolution of diagnostic techniques and methods of operative repair have altered the management and posed new questions in recent years. Methods: This study was a prospectively conducted multicenter trial involving 50 trauma centers in North America under the direction of the Multi-institutional Trial Committee of the American Association for the Surgery of Trauma. Results: There were 274 blunt aortic injury cases studied over 2.5 years, of which 81% were caused by automobile crashes. Chest computed tomography and transesophageal echocardiography were applied in 88 and 30 cases, respectively, and were 75 and 80% diagnostic, respectively. Two hundred seven stable patients underwent planned thoracotomy and repair. Clamp and sew technique was used in 73 (35%) and bypass techniques in 134 (65%). Overall mortality was 31%, with 63% of deaths being attributable to aortic rupture; mortality was not affected by method of repair. Paraplegia occurred postoperatively in 8.7%. Logistic regression analysis demonstrated clamp and sew (p = 0.002) and aortic cross clamp time of 30 minutes (p = 0.01) to be associated with development of postoperative paraplegia. Conclusions: Rupture after hospital admission remains a major problem. Although newer diagnostic techniques are being applied, at this time aortography remains the diagnostic standard. Aortic cross clamp time beyond 30 minutes was associated with paraplegia; bypass techniques, which provide distal aortic perfusion, produced significantly lower paraplegia rates than the clamp and sew approach.
TL;DR: Initial empirical studies indicate that the technique can significantly reduce the cost of regression testing modified software and is at lease as precise as other safe regression test selection algorithms.
Abstract: Regression testing is an expensive but necessary maintenance activity performed on modified software to provide confidence that changes are correct and do not adversely affect other portions of the softwore. A regression test selection technique choses, from an existing test set, thests that are deemed necessary to validate modified software. We present a new technique for regression test selection. Our algorithms construct control flow graphs for a precedure or program and its modified version and use these graphs to select tests that execute changed code from the original test suite. We prove that, under certain conditions, the set of tests our technique selects includes every test from the original test suite that con expose faults in the modified procedfdure or program. Under these conditions our algorithms are safe. Moreover, although our algorithms may select some tests that cannot expose faults, they are at lease as precise as other safe regression test selection algorithms. Unlike many other regression test selection algorithms, our algorithms handle all language constructs and all types of program modifications. We have implemented our algorithms; initial empirical studies indicate that our technique can significantly reduce the cost of regression testing modified software.
TL;DR: The most appropriate management practices to increase soil carbon sink capacity vary regionally, dependent on both environmental and socioeconomic factors as discussed by the authors. But, effective mitigation policies will not be based on any single ‘magic bullet’ solutions, but rather on many modest reductions which are economically efficient and which confer additional benefits to society.
Abstract: . Agricultural soils, having been depleted of much of their native carbon stocks, have a significant CO2 sink capacity. Global estimates of this sink capacity are in the order of 20-30 Pg C over the next 50-100 years. Management practices to build up soil C must increase the input of organic matter to soil and/or decrease soil organic matter decomposition rates. The most appropriate management practices to increase soil C vary regionally, dependent on both environmental and socioeconomic factors.
In temperate regions, key strategies involve increasing cropping frequency and reducing bare fallow, increasing the use of perennial forages (including N-fixing species) in crop rotations, retaining crop residues and reducing or eliminating tillage (i.e. no-till). In North America and Europe, conversion of marginal arable land to permanent perennial vegetation, to protect fragile soils and landscapes and/or reduce agricultural surpluses, provides additional opportunities for C sequestration.
In the tropics, increasing C inputs to soil through improving the fertility and productivity of cropland and pastures is essential. In extensive systems with vegetated fallow periods (e.g. shifting cultivation), planted fallows and cover crops can increase C levels over the cropping cycle. Use of no-till, green manures and agroforestry are other beneficial practices. Overall, improving the productivity and sustainability of existing agricultural lands is crucial to help reduce the rate of new land clearing, from which large amounts of CO2 from biomass and soil are emitted to the atmosphere.
Some regional analyses of soil C sequestration and sequestration potential have been performed, mainly for temperate industrialized countries. More are needed, especially for the tropics, to capture region-specific interactions between climate, soil and management resources that are lost in global level assessments.
By itself, C sequestration in agricultural soils can make only modest contributions (e.g. 3-6% of total fossil C emissions) to mitigating greenhouse gas emissions. However, effective mitigation policies will not be based on any single ‘magic bullet’ solutions, but rather on many modest reductions which are economically efficient and which confer additional benefits to society. In this context, soil C sequestration is a significant mitigation option. Additional advantages of pursuing strategies to increase soil C are the added benefits of improved soil quality for improving agricultural productivity and sustainability.
TL;DR: Investigation of fibroblasts from SMA patients with various clinical severities of SMA showed a moderate reduction in the amount of SMN protein, particularly in type I (most severe) patients, which is consistent with features of this motor neuron disease.
Abstract: The 38 kDa survival motor neuron (SMN) protein is encoded by two ubiquitously expressed genes: telomeric SMN (SMN(T)) and centromeric SMN (SMN(C)). Mutations in SMN(T), but not SMN(C), cause proximal spinal muscular atrophy (SMA), an autosomal recessive disorder that results in loss of motor neurons. SMN is found in the cytoplasm and nucleus. The nuclear form is located in structures termed gems. Using a panel of anti-SMN antibodies, we demonstrate that the SMN protein is expressed from both the SMN(T) and SMN(C) genes. Western blot analysis of fibroblasts from SMA patients with various clinical severities of SMA showed a moderate reduction in the amount of SMN protein, particularly in type I (most severe) patients. Immunocytochemical analysis of SMA patient fibroblasts indicates a significant reduction in the number of gems in type I SMA patients and a correlation of the number of gems with clinical severity. This correlation to phenotype using primary fibroblasts may serve as a useful diagnostic tool in an easily accessible tissue. SMN is expressed at high levels in brain, kidney and liver, moderate levels in skeletal and cardiac muscle, and low levels in fibroblasts and lymphocytes. In SMA patients, the SMN level was moderately reduced in muscle and lymphoblasts. In contrast, SMN was expressed at high levels in spinal cord from normals and non-SMA disease controls, but was reduced 100-fold in spinal cord from type I patients. The marked reduction of SMN in type I SMA spinal cords is consistent with the features of this motor neuron disease. We suggest that disruption of SMN(T) in type I patients results in loss of SMN from motor neurons, resulting in the degeneration of these neurons.
TL;DR: In the fungi, nitrogen metabolism is controlled by a complex genetic regulatory circuit which ensures the preferential use of primary nitrogen sources and also confers the ability to use many different secondary nitrogen sources when appropriate.
Abstract: In the fungi, nitrogen metabolism is controlled by a complex genetic regulatory circuit which ensures the preferential use of primary nitrogen sources and also confers the ability to use many different secondary nitrogen sources when appropriate. Most structural genes encoding nitrogen catabolic enzymes are subject to nitrogen catabolite repression, mediated by positive-acting transcription factors of the GATA family of proteins. However, certain GATA family members, such as the yeast DAL80 factor, act negatively to repress gene expression. Selective expression of the genes which encode enzymes for the metabolism of secondary nitrogen sources is often achieved by induction, mediated by pathway-specific factors, many of which have a GAL4-like C6/Zn2 DNA binding domain. Regulation within the nitrogen circuit also involves specific protein-protein interactions, as exemplified by the specific binding of the negative-acting NMR protein with the positive-acting NIT2 protein of Neurospora crassa. Nitrogen metabolic regulation appears to play a significant role in the pathogenicity of certain animal and plant fungal pathogens.
TL;DR: In this article, decision affect theory is used to predict emotional experiences associated with outcomes of decisions, and the authors show that people choose the risky option for which they expect to feel better on average.
Abstract: How do people feel about the outcomes of risky options? Results from two experiments demonstrate that the emotional reaction to a monetary outcome is not a simple function of the utility of that outcome Emotional responses also depend on probabilities and unobtained outcomes Unexpected outcomes have greater emotional impact than expected outcomes Furthermore any given outcome is less pleasant if an unobtained outcome is better We propose an account of emotional experiences associated with outcomes of decisions called decision affect theory It incorporates utilities expectations and counterfactual comparisons into hedonic responses Finally we show that choices between risky options can be described as the maximization of expected emotional experiences as predicted by decision affect theory That is people choose the risky option for which they expect to feel better on average
TL;DR: While the proposed hypothesis implies that changes in activity in cortical ACh simultaneously occur throughout the cortex, the selectivity and precision of the functions of cholinergic function is due to its coordinated interactions with the activity of converging sensory or associational inputs.
TL;DR: Another proof is given, still using a computer, but simpler than Appel and Haken's in several respects, that every loopless planar graph admits a vertex-colouring with at most four different colours.
TL;DR: In this paper, the authors present the findings of an empirical survey of NAPM members in firms with a high level of awareness and frequent applications of green purchasing, and discuss the role of green buying in reducing and eliminating waste.
Abstract: IN BRIEF
Over the last two decades, growing concerns about ecosystem quality have led to a renewed interest in environmentalism. Purchasing professionals should also be concerned and need to rethink purchasing strategies which have traditionally neglected environmental impacts. To help foster environmentally concerned purchasing strategies, this article presents the findings of an empirical survey of NAPM members in firms with a high level of awareness and frequent applications of “green” purchasing. Environmental factors are identified that may reshape supplier selection decisions. The role of “green” purchasing in reducing and eliminating waste is discussed. Also, effects of “green” purchasing on packaging decisions are explored. Finally, some important practical guidelines are suggested which may enhance the effectiveness of regulatory compliance, pollution prevention, and resource recovery.
TL;DR: In this paper, a cyclone detection and tracking algorithm, applied to twice-daily sea level pressure (SLP) fields for the period 1966-93, is used to examine the characteristics of cyclone activity associated with the locus of the mean Icelandic low (IL), variability during extremes of the North Atlantic oscillation (NAO), and recent changes in relation to circulation over the Northern Hemisphere.
Abstract: Output from a cyclone detection and tracking algorithm, applied to twice-daily sea level pressure (SLP) fields for the period 1966–93, is used to examine the characteristics of cyclone activity associated with the locus of the mean Icelandic low (IL), variability during extremes of the North Atlantic oscillation (NAO), and recent changes in relation to circulation over the Northern Hemisphere. Cyclone events within the climatological IL display a modest seasonal cycle with a winter maximum. However, winter systems are considerably deeper than their summer counterparts with much larger maximum deepening rates. During the cold season (October–March), IL cyclone intensities are typical of oceanic systems but exhibit lower maximum deepening rates. During the warm season (April–September), intensities are typical of Northern Hemisphere values with deepening characteristics similar to those for all extratropical oceans. Depending on the month, 10%–15% (13%–18%) of cyclone events in the IL region repres...
TL;DR: Diagnostic accuracy and reproducibility are compromised by the subjective histologic criteria currently used to classify and grade gliomas.
Abstract: BACKGROUND
Accurate histologic diagnosis of gliomas is fundamental to proper patient management and to the interpretation of basic and clinical investigations. Diagnostic accuracy and reproducibility are compromised by the subjective histologic criteria currently used to classify and grade gliomas.
METHODS
The histologic features of 4 sets of gliomas (a total of 244 cases) were reviewed independently by 4 neuropathologists to determine interobserver diagnostic concordance rates. Cases wherein diagnostic disagreements arose were reviewed jointly to identify and refine the histologic criteria that were adversely affecting diagnostic reproducibility. Using the criteria developed in the study, a set of 315 gliomas with known survival data was evaluated in order to validate the usefulness of the criteria.
RESULTS
There was significant improvement in diagnostic concordance with each session (P = 0.02). For the first session, the concordance rates were as follows: all 4 reviewers, 52%; any 3 reviewers, 60%; 2 reviewers, 70%. For the fourth session, the respective rates were 69%, 75%, and 80%. Although features important in grading, particularly microvascular proliferation, were sometimes problematic, most disagreements related to the classification of tumors. Much of the improvement related to the refinement of criteria distinguishing diffuse astrocytomas from oligodendrogliomas/oligoastrocytomas and pilocytic astrocytomas. It was concluded that the presence of any typical oligodendroglioma was sufficient to remove a tumor from the astrocytoma category.
CONCLUSIONS
The authors' data indicate that oligodendroglial tumors comprise up to 25% of gliomas, a significantly higher proportion than was previously recognized. The data also suggest that the wide range of survival times reported for patients with anaplastic astrocytoma may reflect "contamination" resulting from misdiagnosis, particularly of oligodendroglial tumors and pilocytic astrocytomas. Cancer 1997; 79:1381-93. © 1997 American Cancer Society.