Showing papers by "University of Amsterdam published in 1998"
01 Mar 1998
TL;DR: The paradigm shift from a transfer view to a modeling view is discussed and two approaches which considerably shaped research in Knowledge Engineering are described: Role-limiting Methods and Generic Tasks.
Abstract: This paper gives an overview of the development of the field of Knowledge Engineering over the last 15 years. We discuss the paradigm shift from a transfer view to a modeling view and describe two approaches which considerably shaped research in Knowledge Engineering: Role-limiting Methods and Generic Tasks. To illustrate various concepts and methods which evolved in recent years we describe three modeling frameworks: CommonKADS, MIKE and PROTEGE-II. This description is supplemented by discussing some important methodological developments in more detail: specification languages for knowledge-based systems, problem-solving methods and ontologies. We conclude by outlining the relationship of Knowledge Engineering to Software Engineering, Information Integration and Knowledge Management.
3,406 citations
TL;DR: The balance in actions mediated by the two corticosteroid receptor types in these neurons appears critical for neuronal excitability, stress responsiveness, and behavioral adaptation and Dysregulation of this MR/GR balance brings neurons in a vulnerable state with consequences for regulation of the stress response and enhanced vulnerability to disease in genetically predisposed individuals.
Abstract: In this review, we have described the function of MR and GR in hippocampal neurons. The balance in actions mediated by the two corticosteroid receptor types in these neurons appears critical for neuronal excitability, stress responsiveness, and behavioral adaptation. Dysregulation of this MR/GR balance brings neurons in a vulnerable state with consequences for regulation of the stress response and enhanced vulnerability to disease in genetically predisposed individuals. The following specific inferences can be made on the basis of the currently available facts. 1. Corticosterone binds with high affinity to MRs predominantly localized in limbic brain (hippocampus) and with a 10-fold lower affinity to GRs that are widely distributed in brain. MRs are close to saturated with low basal concentrations of corticosterone, while high corticosterone concentrations during stress occupy both MRs and GRs. 2. The neuronal effects of corticosterone, mediated by MRs and GRs, are long-lasting, site-specific, and conditional. The action depends on cellular context, which is in part determined by other signals that can activate their own transcription factors interacting with MR and GR. These interactions provide an impressive diversity and complexity to corticosteroid modulation of gene expression. 3. Conditions of predominant MR activation, i.e., at the circadian trough at rest, are associated with the maintenance of excitability so that steady excitatory inputs to the hippocampal CA1 area result in considerable excitatory hippocampal output. By contrast, additional GR activation, e.g., after acute stress, generally depresses the CA1 hippocampal output. A similar effect is seen after adrenalectomy, indicating a U-shaped dose-response dependency of these cellular responses after the exposure to corticosterone. 4. Corticosterone through GR blocks the stress-induced HPA activation in hypothalamic CRH neurons and modulates the activity of the excitatory and inhibitory neural inputs to these neurons. Limbic (e.g., hippocampal) MRs mediate the effect of corticosterone on the maintenance of basal HPA activity and are of relevance for the sensitivity or threshold of the central stress response system. How this control occurs is not known, but it probably involves a steady excitatory hippocampal output, which regulates a GABA-ergic inhibitory tone on PVN neurons. Colocalized hippocampal GRs mediate a counteracting (i.e., disinhibitory) influence. Through GRs in ascending aminergic pathways, corticosterone potentiates the effect of stressors and arousal on HPA activation. The functional interaction between these corticosteroid-responsive inputs at the level of the PVN is probably the key to understanding HPA dysregulation associated with stress-related brain disorders. 5. Fine-tuning of HPA regulation occurs through MR- and GR-mediated effects on the processing of information in higher brain structures. Under healthy conditions, hippocampal MRs are involved in processes underlying integration of sensory information, interpretation of environmental information, and execution of appropriate behavioral reactions. Activation of hippocampal GRs facilitates storage of information and promotes elimination of inadequate behavioral responses. These behavioral effects mediated by MR and GR are linked, but how they influence endocrine regulation is not well understood. 6. Dexamethasone preferentially targets the pituitary in the blockade of stress-induced HPA activation. The brain penetration of this synthetic glucocorticoid is hampered by the mdr1a P-glycoprotein in the blood-brain barrier. Administration of moderate amounts of dexamethasone partially depletes the brain of corticosterone, and this has destabilizing consequences for excitability and information processing. 7. The set points of HPA regulation and MR/GR balance are genetically programmed, but can be reset by early life experiences involving mother-infant interaction. 8. (ABSTRACT TRUNCATED)
2,548 citations
TL;DR: In this paper, the authors translate, validate, and generate normative data on the SF-36 Health Survey for use among Dutch- speaking residents of the Netherlands, followed the stepwise, iterative procedures developed by the IQOLA Project.
1,957 citations
TL;DR: In this paper, the authors reported the discovery of transient optical emission in the error box of the gamma-ray burst GRB980425, the light curve of which was very different from that of previous optical afterglows associated with Gamma-ray bursts.
Abstract: The discovery of afterglows associated with gamma-ray bursts at X-ray, optical and radio wavelengths and the measurement of the redshifts of some of these events has established that gamma-ray bursts lie at extreme distances, making them the most powerful photon-emitters known in the Universe. Here we report the discovery of transient optical emission in the error box of the gamma-ray burst GRB980425, the light curve of which was very different from that of previous optical afterglows associated with gamma-ray bursts. The optical transient is located in a spiral arm of the galaxy ESO 184-GS2, which has a redshift velocity of only 2,550 km/ s. Its optical spectrum and location indicate that it is a very luminous supernova, which has been identified as SN1998bw. If this supernova and GRB980425 are indeed associated, the energy radiated in gamma-rays is at least four orders of magnitude less than in other gamma-ray bursts, although its appearance was otherwise unremarkable: this indicates that very different mechanisms can give rise to gamma-ray bursts. But independent of this association, the supernova is itself unusual, exhibiting an unusual light curve at radio wavelengths that requires that the gas emitting the radio photons be expanding relativistically.
1,823 citations
TL;DR: In this paper, the authors investigate the dynamics in a simple present discounted value asset pricing model with heterogeneous beliefs, where agents choose from a finite set of predictors of future prices of a risky asset and revise their "beliefs" in each period in a boundedly rational way, according to a fitness measure such as past realized profits.
1,735 citations
TL;DR: Three-dimensional crystals of air spheres in titania with radii between 120 and 1000 nanometers were made by filling the voids in artificial opals by precipitation from a liquid-phase chemical reaction and subsequently removing the original opal material by calcination and are a new class of photonic band gap crystals for the optical spectrum.
Abstract: Three-dimensional crystals of air spheres in titania (TiO 2 ) with radii between 120 and 1000 nanometers were made by filling the voids in artificial opals by precipitation from a liquid-phase chemical reaction and subsequently removing the original opal material by calcination. These macroporous materials are a new class of photonic band gap crystals for the optical spectrum. Scanning electron microscopy, Raman spectroscopy, and optical microscopy confirm the quality of the samples, and optical reflectivity demonstrates that the crystals are strongly photonic and near that needed to exhibit band gap behavior.
1,532 citations
TL;DR: A new classification system based on co-receptor use is proposed, providing a more accurate description of viral phenotype than the present imprecise and often misleading classification schemes.
Abstract: The phenotype of HIV-1 isolates is defined by the cells in which they replicate in vitro, but these phenotypes can change in vivo with profound implications for viral transmission, pathogenesis and disease progression. Here we propose a new classification system based on co-receptor use, providing a more accurate description of viral phenotype than the present imprecise and often misleading classification schemes.
873 citations
TL;DR: For the assessment of beat-to-beat changes in blood pressure and assessment of blood pressure variability Finapres proved a reliable alternative for invasive measurements when mean and diastolic pressures are concerned and accuracy and precision usually suffice for reliable tracking of changes inBlood pressure.
Abstract: We review the Finapres technology, embodied in several TNO-prototypes and in the Ohmeda 2300 and 2300e Finapres NIBP. Finapres is an acronym for FINger Arterial PRESsure, the device delivers a continuous finger arterial pressure waveform. Many papers report on the accuracy of the device in comparison with intra-arterial or with noninvasive but intermittent blood pressure measurements. We compiled the results of 43 such papers and found systolic, diastolic and mean accuracies, in this order, ranging from -48 to 30 mmHg, from -20 to 18 mmHg, and from -13 to 25 mmHg. Weighted for the number of subjects included pooled accuracies were -0.8 (SD 11.9), -1.6 (8.3) and -1.6 (7.6) mmHg respectively. Subdividing the pooled group according to criteria such as reference blood pressure, place of application, and prototype or commercial device we found no significant differences in mean differences or SD. Measurement at the finger allows uninterrupted recordings of long duration. The transmission of the pressure pulse along the arm arteries, however, causes distortion of the pulse waveform and depression of the mean blood pressure level. These effects can be reduced by appropriate filtering, and upper arm 'return-to-flow' calibration to bring accuracy and precision within AAMI limits. For the assessment of beat-to-beat changes in blood pressure and assessment of blood pressure variability Finapres proved a reliable alternative for invasive measurements when mean and diastolic pressures are concerned. Differences in systolic pressure are larger and reach statistical significance but are not of clinical relevance. Finger arteries are affected by contraction and dilatation in relation to psychological and physical (heat, cold, blood loss, orthostasis) stress. Effects of these phenomena are reduced by the built-in Physiocal algorithm. However, full smooth muscle contraction should be avoided in the awake patient by comforting the patient, and coveting the hand. Arterial state can be monitored by observing the behaviour of the Physiocal algorithm. We conclude that Finapres accuracy and precision usually suffice for reliable tracking of changes in blood pressure. Diagnostic accuracy may be achieved with future application of corrective measures.
861 citations
01 Jan 1998
TL;DR: In this paper, the authors present a cross-lingual alignment of EuroWordNet with an Inter-Lingual-Index (ILI-Index) based on crosslingual similarity measure.
Abstract: Introduction to EuroWordNet P. Vossen. The Linguistic Design of the EuroWordNet Database A. Alonge, et al. Compatibility in Interpretation of Relations in EuroWordNet P. Vossen, et al. A Semantic Network of English: The Mother of All WordNets C. Fellbaum. Cross-Linguistic Alignment of Wordnets with an Inter-Lingual-Index W. Peters, et al.
852 citations
TL;DR: The Triple Helix thesis is developed into a recursive model of how an overlay of communications operates on the underlying institutions, and a regime of transitions emerges when trajectories can be recombined.
Abstract: The Second Conference on the Triple Helix of University-Industry-Government Relations focused on “the future location of research.” In this report, the Triple Helix thesis is developed into a recursive model of how an overlay of communications operates on the underlying institutions. Market selections, innovative dynamics, and network controls provide different codes of communication at the global level. Local translations at the interfaces induce adaptation mechanisms in the institutional arrangements. While two dynamics tend to coevolve into trajectories, a regime of transitions emerges when trajectories can be recombined. The emerging hyper-networks are expected to be in flux. Institutions can then be flexible in temporarily assuming roles of other partners. Niche management and human capital management become crucial. Copyright , Beech Tree Publishing.
778 citations
TL;DR: Contrary to predictions, anxious children did not demonstrate enhanced levels of response inhibition and consistent and robust evidence was found for a response inhibition deficit in AD/HD.
Abstract: The aim of this study was to investigate whether impaired response inhibition is uniquely related to AD/HD or whether deficits in response inhibition are also evident in other psychopathological disorders. Furthermore, the suggestion was examined that anxiety disorders are associated with abnormally high levels of response inhibition. This paper presents the results of a meta-analysis of eight studies in which response inhibition was assessed with the so-called stop task in five groups of children: children with attention deficit/hyperactivity disorder (AD/HD), children with conduct disorder (CD), children with AD/HD + CD, children with anxiety disorders, and control children. A total of 456 children participated in the 8 studies. All children were in the age range 6-12 years. Consistent and robust evidence was found for a response inhibition deficit in AD/HD. However, response inhibition deficits did not distinguish children with AD/HD from children with CD, nor from children with comorbid AD/HD + CD. Contrary to predictions, anxious children did not demonstrate enhanced levels of response inhibition.
TL;DR: It is shown, using mathematical modeling, that redistribution of T cells to the blood can explain the striking correlation between the initial CD4+ and CD8+ memory T-cell repopulation and the observation that 3 weeks after the start of treatment memory CD4-cell numbers reach a plateau.
Abstract: The origin of CD4+ T cells reappearing in the blood following antiretroviral therapy in human immunodeficiency virus type-1 (HIV-1) infection is still controversial. Here we show, using mathematical modeling, that redistribution of T cells to the blood can explain the striking correlation between the initial CD4+ and CD8+ memory T-cell repopulation and the observation that 3 weeks after the start of treatment memory CD4+ T-cell numbers reach a plateau. The increase in CD4+ T cells following therapy most likely is a composite of initial redistribution, accompanied by a continuous slow repopulation with newly produced naive T cells.
TL;DR: In this paper, the authors reported the discovery of a millisecond radio pulsar in the persistent flux of an X-ray binary system, confirming theoretical expectations, but without direct proof.
Abstract: Ordinary radio pulsars1 are neutron stars with magnetic fields of ∼1012 gauss and spin periods in the range 0.1 to 3 seconds. In contrast, millisecond radio pulsars2 have much weaker fields (∼109 gauss) and faster, millisecond spin rates. For both types of pulsar, the energy driving the radio pulsations is thought to be derived from the rotation of the neutron star. The star gradually ‘spins down’ as energy is radiated away. Millisecond radio pulsars are often located in binary systems3. In a widely accepted theoretical model4,5, they started as ordinary pulsars which lost most of their magnetic field and were ‘spun up’ to millisecond periods by the accretion of matter from a companion star in an X-ray binary system. Evidence6,7,8,9,10,11 for this model has gradually mounted, but direct proof—in the form of the predicted coherent millisecond X-ray pulsations in the persistent flux of an X-ray binary has been lacking, despite many searches12,13,14,15. Here we report the discovery16 of such a pulsar, confirming theoretical expectations. The source will probably become a millisecond radio pulsar when the accretion turns off completely.
TL;DR: Biopsy of the Sentinel node (SN) is a highly accurate, minimally invasive method of staging patients with breast cancer and can substantially reduce the morbidity and costs of surgical treatment by avoiding unnecessary ALND in the majority of patients.
Abstract: Background: Sentinel node (SN) biopsy appears to offer an alternative to routine axillary lymph node dissection (ALND) for staging patients with breast cancer Various techniques have been studied for identifying the SN, using vital blue dye or radioactive colloid, and initial reports are promising The inherent limitations and pitfalls must be clearly understood before SN biopsy can be implemented in clinical practice Study Design: In a prospective trial, the feasibility of using lymphoscintigraphy and gamma probe detection for performing SN biopsy was studied In 130 consecutive patients with T1–T2, N0 breast cancer, preoperative lymphoscintigraphy was performed with technetium 99m-colloidal albumin During ALND, the radioactive axillary SNs were localized by the gamma probe Histopathologic examination of the harvested SNs was compared with the status of the axillary lymph nodes Results: Axillary focal accumulations were clearly identified on lymphoscintigraphy in 116 patients (89%) The failure rate was significantly higher in patients who had a previous excision biopsy (36%) than in those with a palpable tumor in situ (4%) Using the gamma probe, radiolabeled axillary SNs were successfully biopsied in 122 patients (94%) Because 18 of these patients did not undergo formal lymphadenectomy, the predictive accuracy of SN biopsy was analyzed in 104 patients Radioactive nodes revealed metastases in 44 of 104 patients (42%); in 26 of them (59%), these were the only involved axillary nodes The SN was negative in 60 patients (58%); in one patient the ALND was found to contain metastatic disease (17% false negatives) Biopsy of the SN was 98% accurate in predicting the absence of nodal metastases Conclusions: There are certain guidelines for performing SN biopsy by lymphoscintigraphy and gamma probe detection Success depends primarily on an adequate functional capacity of the SN, necessary for sufficient nodal uptake to ensure accurate identification Lymphoscintigraphy defines the pattern of lymph flow and may prevent failure or false-negative biopsies Biopsy of the SN is a highly accurate, minimally invasive method of staging patients with breast cancer and can substantially reduce the morbidity and costs of surgical treatment by avoiding unnecessary ALND in the majority of patients
TL;DR: The 20210A prothrombin variant is a common abnormality, with a prevalence of carriership between one and four percent, and is more common in southern than in northern Europe.
Abstract: A variant in prothrombin (clotting factor II), a G to A transition at nucleotide position 20210, has recently been shown to be associated with the prothrombin plasma levels and the risk of both venous and arterial thrombosis. The purpose of this study was to investigate the prevalence of carriership of this mutation in various populations. We combined data from 11 centres in nine countries, where tests for this mutation had been performed in groups representing the general population. We calculated an overall prevalence estimate, by a precision-weighted method, and, since the distribution of the prevalences did not appear homogeneous, by an unweighted average of the prevalences. We examined differences in the prevalences by geographical location and ethnic background as a possible explanation for the heterogeneity. Among a total of 5527 individuals who had been tested, 111 heterozygous carriers of the 20210A mutation were found. The prevalence estimates varied from 0.7 to 4.0 between the centres. The overall prevalence estimate was 2.0 percent (CI95 1.4-2.6%). The variation around the summary estimate appeared more than was expected by chance alone, and this heterogeneity could be explained by geographic differences. In southern Europe, the prevalence was 3.0 percent (CI95 2.3 to 3.7%), nearly twice as high as the prevalence in northern Europe (1.7%, CI95 1.3 to 2.2%). The prothrombin variant appeared very rare in individuals from Asian and African descent. The 20210A prothrombin variant is a common abnormality, with a prevalence of carriership between one and four percent. It is more common in southern than in northern Europe. Since this distribution within Europe is very different to that of another prothrombotic mutation (factor V Leiden or factor V R506Q), founder effects are the most likely explanation for the geographical distribution of both mutations.
TL;DR: Les nouvelles directions que peuvent prendre les theoremes de Tarski dans un environnement mathematique are indique celle des contraintes structurelles speciales, des extensions infinies, de the logique modale etendue and d'une semantique dynamique.
Abstract: Definition des fragments modaux de la logique des predicats a partir de formules du premier ordre qui sont des traductions des proprietes poly-modales elementaires. Distinguant les fragments variables et finis des fragments lies a un quantificateur, l'A. developpe une version semantique des fragments gardes en remplacant les liens syntaxiques par des restrictions sur les types d'attribution dans les modeles generalises. Se referant a l'algebre cylindrique, l'A. indique les nouvelles directions que peuvent prendre les theoremes de Tarski dans un environnement mathematique: celle des contraintes structurelles speciales, des extensions infinies, de la logique modale etendue et d'une semantique dynamique
TL;DR: It is indicated that IL-17 is a proinflammatory cytokine, which could amplify the development of cutaneous inflammation and may support the maintenance of chronic dermatoses, through stimulation of keratinocytes to augment their secretion of pro inflammatory cytokines.
TL;DR: The discovery of the unusual supernova SN1998bw, and its possible association with the γ-ray burst GRB 9804251,2,3, provide new insights into the explosion mechanism of very massive stars and the origin of some classes of gamma-ray bursts.
Abstract: The discovery of the unusual supernova SN1998bw, and its possible association with the γ-ray burst GRB 9804251,2,3, provide new insights into the explosion mechanism of very massive stars and the origin of some classes of γ-ray bursts. Optical spectra indicate that SN1998bw is a type Ic supernova3,4, but its peak luminosity is unusually high compared with typical type Ic supernovae3. Here we report our findings that the optical spectra and the light curve of SN1998bw can be well reproduced by an extremely energetic explosion of a massive star composed mainly of carbon and oxygen (having lost its hydrogen and helium envelopes). The kinetic energy of the ejecta is as large as +(2–5)× 1052 erg, more than ten times that of previously observed supernovae. This type of supernova could therefore be termed ‘hypernova’. The extremely large energy suggests the existence of a new mechanism of massive star explosion that can also produce the relativistic shocks necessary to generate the observed γ-rays.
TL;DR: There was a low frequency of pneumonia, sepsis, and bacteraemia in patients with multiple trauma who received glutamine-supplemented enteral nutrition.
TL;DR: Whereas receptive field tuning properties reflect feedforward processing, modulations evoked by horizontal and feedback connections may reflect the integration of information that underlies perception.
TL;DR: In this article, the impact of nitrogen (N) deposition was studied by comparing N fluxes, N concentrations and N pool sizes in vegetation and soil in five coniferous forest stands at the NITREX sites: Gardsjon (GD), Sweden, Klosterhede (KH), Denmark, Aber (AB), Wales, UK, Speuld (SP, the Netherlands, and Ysselsteyn (YS), the Netherlands.
TL;DR: Data indicate that important differences exist in the cellular infiltrate and ECM expression patterns of acute, healing versus chronic wounds, which may be related to the nonhealing status of chronic wounds.
TL;DR: In this article, an isotope-based method was used to estimate sea level and global ice-volume from the recent geological past using fossil coral-reef terraces or oxygen-isotope records from benthic foraminifera.
Abstract: Existing techniques for estimating natural fluctuations of sea level and global ice-volume from the recent geological past exploit fossil coral-reef terraces or oxygen-isotope records from benthic foraminifera. Fossil reefs reveal the magnitude of sea-level peaks (highstands) of the past million years, but fail to produce significant values for minima (lowstands) before the Last Glacial Maximum (LGM) about 20,000 years ago, a time at which sea level was about 120 m lower than it is today1,2,3,4. The isotope method provides a continuous sea-level record for the past 140,000 years (ref. 5) (calibrated with fossil-reef data6), but the realistic uncertainty in the sea-level estimates is around ±20 m. Here we present improved lowstand estimates—extending the record back to 500,000 years before present—using an independent method based on combining evidence of extreme high-salinity conditions in the glacial Red Sea with a simple hydraulic control model of water flow through the Strait of Bab-el-Mandab, which links the Red Sea to the open ocean. We find that the world can glaciate more intensely than during the LGM by up to an additional 20-m lowering of global sea-level. Such a 20-m difference is equivalent to a change in global ice-volume of the order of today's Greenland and West Antarctic ice-sheets.
TL;DR: The results indicate that CTGF may be a common growth factor involved in renal fibrosis, and an increase in the number of cells expressing CTGF mRNA was observed at sites of chronic tubulointerstitial damage, which correlated with the degree of damage.
TL;DR: The class of problems gstat can solve is described, and aspects of efficiency and implementation, managing geostatistical projects, and relevant technical details are addressed.
01 Jan 1998
TL;DR: The main objective of the conference was to highlight and summarize the rapid advancements in the field, including numerical methods for computing the single and multiple scattering of electromagnetic radiation by nonspherical and heterogeneous particles, measurement approaches, knowledge of characteristic features in scattering patterns, retrieval and remote sensing techniques, nonsphericals particle sizing, and various practical applications.
Abstract: Improved understanding of electromagnetic scattering by nonspherical particles is important to many science and engineering disciplines and was the subject of the Conference on Light Scattering by Nonspherical Particles: Theory, Measurements, and Applications. The conference was held 29 September-1 October 1998 at the Goddard Institute for Space Studies in New York City and brought together 115 participants from 18 countries. The main objective of the conference was to highlight and summarize the rapid advancements in the field, including numerical methods for computing the single and multiple scattering of electromagnetic radiation by nonspherical and heterogeneous particles, measurement approaches, knowledge of characteristic features in scattering patterns, retrieval and remote sensing techniques, nonspherical particle sizing, and various practical applications. The conference consisted of twelve oral and one poster sessions. The presentations were loosely grouped based on broad topical categories. In each of these categories invited review talks highlighted and summarized specific active areas of research. To ensure a high-quality conference, all abstracts submitted had been reviewed by members of the Scientific Organizing Committee for technical merit and content. The conference program was published in the June 1998 issue of the Bulletin of the American Meteorological Society and is available on the World Wide Web at http://www.giss.nasa.gov/-crmim/conference/program.html. Authors of accepted papers and review presentations contributed to a volume of preprints published by the American Meteorological Society' and distributed to participants at the conference.
TL;DR: In this article, a set of polymerase chain reaction (PCR) primers, designated SPF1 and SPF2 and located in the L1 region, was developed for universal detection of human papillomavirus (HPV).
Abstract: A novel set of polymerase chain reaction (PCR) primers, designated SPF1 and SPF2 and located in the L1 region, was developed for universal detection of human papillomavirus (HPV). A short PCR fragment (SPF) of only 65 pb was synthesized. SPF amplimers were detected in a microtiter-based hybridization system, using a mixture of oligonucleotide probes. The SPF system allowed detection of at least 43 different HPV genotypes. The clinical performance of the novel SPF system was assessed in three different patient groups. 1) Analysis of 534 cervical scrapes, obtained from treated patients, showed that the detection rate in 447 (83.7%) scrapes with normal cytology was significantly higher using the SPF system as compared with the universal primer set GP5+/6+ (P < 0.001). 2) The SPF assay detected HPV DNA in 299 (98.4%) of 304 scrapes with cytological dyskaryosis. 3) The SPF system detected HPV DNA in 100% of 184 formalin-fixed, paraffin-embedded cervical carcinoma specimens. In conclusion, the novel SPF system permitted universal and highly sensitive detection of HPV DNA in diverse clinical materials and may improve the molecular diagnosis and epidemiology of this important virus.
TL;DR: In this article, the authors provide a strategic rationale for growth options under uncertainty and imperfect competition, and show that when the strategic advantage is strong, increased uncertainty encourages investment in growth options: higher uncertainty means more opportunity rather than simply larger risk.
Abstract: We provide a strategic rationale for growth options under uncertainty and imperfect competition. In a market with strategic competition, investment confers a greater capability to take advantage of future growth opportunities. This strategic advantage leads to the capture of a greater share of the market, either by dissuading entry or by inducing competitors to "make room" for the stronger competitor. As a result of this strategic effect, payoffs are in a rough sense more convex than in the case of no investment in a growth option. When the strategic advantage is strong, increased uncertainty encourages investment in growth options: higher uncertainty means more opportunity rather than simply larger risk. If the strategic effect is weak, the reverse is true. On the other hand, an increase in systematic risk discourages the acquisition of growth options. Our results contradict the view that volatility is a strong disincentive for investment.
Posted Content•
TL;DR: In this article, it was shown that the exponential quantum speed-up obtained for partial functions (i.e., problems involving a promise on the input) by Deutsch and Jozsa and by Simon cannot be obtained for any total function, and that there is a classical deterministic algorithm that computes some total Boolean function f with bounded-error using T black-box queries.
Abstract: We examine the number T of queries that a quantum network requires to compute several Boolean functions on {0,1}^N in the black-box model. We show that, in the black-box model, the exponential quantum speed-up obtained for partial functions (i.e. problems involving a promise on the input) by Deutsch and Jozsa and by Simon cannot be obtained for any total function: if a quantum algorithm computes some total Boolean function f with bounded-error using T black-box queries then there is a classical deterministic algorithm that computes f exactly with O(T^6) queries.
We also give asymptotically tight characterizations of T for all symmetric f in the exact, zero-error, and bounded-error settings. Finally, we give new precise bounds for AND, OR, and PARITY. Our results are a quantum extension of the so-called polynomial method, which has been successfully applied in classical complexity theory, and also a quantum extension of results by Nisan about a polynomial relationship between randomized and deterministic decision tree complexity.
Book•
01 Jan 1998TL;DR: This monograph Giannakidou presents a novel theory of polarity which avoids the empirical and conceptual problems of previous approaches by introducing a notion wider than negation and downward entailment: (non)veridicality.
Abstract: Polarity phenomena have been known to linguists since Klima’s seminal work on English negation. In this monograph Giannakidou presents a novel theory of polarity which avoids the empirical and conceptual problems of previous approaches by introducing a notion wider than negation and downward entailment: (non)veridicality. The leading idea is that the various polarity phenomena observed in language are manifestations of the dependency of certain expessions, i.e. polarity items, to the (non)veridicality of the context of appearence. Dependencies to negation or downward entailment emerge as subcases of nonveridicality.The (non)veridical dependency may be positive (licensing), or negative (anti-licensing), and arises from the sensitivity semantics of polarity items. The book is also concerned with the syntactic mapping of the sensitivity dependency. It is argued that licensing does not necessarily correspond to a requirement that the licensee be in the scope of the licenser. In some cases, for instance for the interpretation of negative concord, the reverse is required: that the licensee takes the licenser in its scope. The theory is applied to an extended set of old and new data concerning affective, free-choice dependencies, and mood choice in relative clauses. The primary focus is on Greek, but data from Dutch, English, and to a lesser extend Romance and Slavic, are also considered.