71 research outputs found
Law and economics of Microsoft vs. U.S. Department of Justice - New paradigm for antitrust in network markets or inefficient lock-in of antitrust policy?
This paper contains an economic and legal analysis of the lawsuit Microsoft vs. U.S. Department of Justice beginning with the District Court's decision on June 7, 2000 up to the Proposed Final Judgement on November 6, 2001. I found that the courts' underlying economic paradigm regarding the assessment of monopoly power in 'New Economy Network Markets' was strongly influenced by BRIAN W. ARTHUR's theory of path dependence claiming (1) that high-technology markets being subject to network effects generally involve a danger of being locked-in to an inferior technology since winning or losing in a technology race is determined by small early random historical events and not by economic efficiency and (2) that there is almost no possibility to overcome inferior lock-in positions since network (compatibility) effects create insurmountable switching costs protecting the lock-in monopolist. As to Microsoft, it was often claimed that Macintosh would have been the better solution than Windows. The U.S. courts are convinced that rivals such as Linux wouldn't have any chance to overcome Microsoft's lock-in position without any antitrust intervention. However, I argue in accordance with opponents of ARTHUR's work that path dependence theory is only a theoretical curiosity that lacks empirical evidence. The predominance of a certain technology and especially the predominance of Windows in the operating system market is determined by economic efficiency and dominant market positions can be eroded very quickly by providing better quality. There is no empirical indication that network effects protect Microsoft's monopoly as it was claimed by the courts within their 'applications barrier to entry' theory. I claim that current interpretations of the U.S. antitrust law don't meet the requirements of fair competition rules in the 'New Economy'. If plaintiffs and the U.S. Department of Justice are victorious over Microsoft and lock-in theories become generally accepted by courts and market participants, further antitrust lawsuits are going to follow since most markets in the 'New Economy' are subject to network effects and high seller concentration. Strict antitrust policy could dampen economic growth due to investor uncertainty and the impossibility to take advantage of scale-based productivity effects. --Microsoft,antitrust,network effects,path dependence
Law and economics of Microsoft vs. U.S. Department of Justice : new paradigm for antitrust in network markets or inefficient lock-in of antitrust policy?
This paper contains an economic and legal analysis of the lawsuit Microsoft vs. U.S. Department of Justice beginning with the District Court?s decision on June 7, 2000 up to the Proposed Final Judgement on November 6, 2001. I found that the courts? underlying economic paradigm regarding the assessment of monopoly power in ?New Economy Network Markets? was strongly influenced by BRIAN W. ARTHUR?s theory of path dependence claiming (1) that high-technology markets being subject to network effects generally involve a danger of being locked-in to an inferior technology since winning or losing in a technology race is determined by small early random historical events and not by economic efficiency and (2) that there is almost no possibility to overcome inferior lock-in positions since network (compatibility) effects create insurmountable switching costs protecting the lock-in monopolist. As to Microsoft, it was often claimed that Macintosh would have been the better solution than Windows. The U.S. courts are convinced that rivals such as Linux wouldn?t have any chance to overcome Microsoft?s lock-in position without any antitrust intervention. However, I argue in accordance with opponents of ARTHUR?s work that path dependence theory is only a theoretical curiosity that lacks empirical evidence. The predominance of a certain technology and especially the predominance of Windows in the operating system market is determined by economic efficiency and dominant market positions can be eroded very quickly by providing better quality. There is no empirical indication that network effects protect Microsoft?s monopoly as it was claimed by the courts within their ?applications barrier to entry? theory. I claim that current interpretations of the U.S. antitrust law don?t meet the requirements of fair competition rules in the ?New Economy?. If plaintiffs and the U.S. Department of Justice are victorious over Microsoft and lock-in theories become generally accepted by courts and market participants, further antitrust lawsuits are going to follow since most markets in the ?New Economy? are subject to network effects and high seller concentration. Strict antitrust policy could dampen economic growth due to investor uncertainty and the impossibility to take advantage of scale-based productivity effects
Effectiveness of seasonal trivalent inactivated influenza vaccine in preventing influenza hospitalisations and primary care visits in Auckland, New Zealand, in 2013
This study reports the first vaccine effectiveness (VE) estimates for the prevention of general practice visits and hospitalisations for laboratory-confirmed influenza from an urban population in Auckland, New Zealand, in the same influenza season (2013). A case test-negative design was used to estimate propensity-adjusted VE in both hospital and community settings. Patients with a severe acute respiratory infection (SARI) or influenza-like illness (ILI) were defined as requiring hospitalisation (SARI) or attending a general practice (ILI) with a history of fever or measured temperature ≥38 °C, cough and onset within the past 10 days. Those who tested positive for influenza virus were cases while those who tested negative were controls. Results were analysed to 7 days post symptom onset and adjusted for the propensity to be vaccinated and the timing during the influenza season. Influenza vaccination provided 52% (95%CI: 32 to 66) protection against laboratory-confirmed influenza hospitalisation and 56% (95%CI: 34 to 70) against presenting to general practice with influenza. VE estimates were similar for all typeand subtypes. This study found moderate effectiveness of influenza vaccine against medically attended and hospitalised influenza in New Zealand, a temperate, southern hemisphere country during the 2013 winter season
Graft-versus-Host disease Prophylaxis with Everolimus and Tacrolimus Is Associated with a High Incidence of Sinusoidal Obstruction Syndrome and Microangiopathy: Results of the EVTAC Trial
AbstractA calcineurin inhibitor combined with methotrexate is the standard prophylaxis for graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT). Everolimus, a derivative of sirolimus, seems to mediate antileukemia effects. We report on a combination of everolimus and tacrolimus in 24 patients (median age, 62 years) with either myelodysplastic syndrome (MDS; n = 17) or acute myeloid leukemia (AML; n = 7) undergoing intensive conditioning followed by HSCT from related (n = 4) or unrelated (n = 20) donors. All patients engrafted, and only 1 patient experienced grade IV mucositis. Nine patients (37%) developed acute grade II-IV GVHD, and 11 of 17 evaluable patients (64%) developed chronic extensive GVHD. Transplantation-associated microangiopathy (TMA) occurred in 7 patients (29%), with 2 cases of acute renal failure. The study was terminated prematurely because an additional 6 patients (25%) developed sinusoidal obstruction syndrome (SOS), which was fatal in 2 cases. With a median follow-up of 26 months, the 2-year overall survival rate was 47%. Although this new combination appears to be effective as a prophylactic regimen for acute GVHD, the incidence of TMA and SOS is considerably higher than seen with other regimens
Two for One -- Combined Morphologic and Quantitative Knee Joint MRI Using a Versatile Turbo Spin-Echo Platform
Introduction: Quantitative MRI techniques such as T2 and T1\r{ho} mapping are
beneficial in evaluating knee joint pathologies; however, long acquisition
times limit their clinical adoption. MIXTURE (Multi-Interleaved X-prepared
Turbo-Spin Echo with IntUitive RElaxometry) provides a versatile turbo
spin-echo (TSE) sequence platform for simultaneous morphologic and quantitative
joint imaging yet lacks comparative evaluation in basic and translational
research contexts.
Methods: Two MIXTURE sequences were designed along clinical requirements: (i)
MIX1, combining proton density (PD)-weighted fat-saturated (FS) images and
quantitative T2 mapping (acquisition time: 4:59 min), and (ii) MIX2, combining
T1-weighted images with quantitative T1\r{ho} mapping (6:38 min). MIXTURE
sequences and their reference 2D and 3D TSE counterparts were acquired from ten
human cadaveric knee joints using a clinical 3T MRI scanner and knee coil.
Contrast, contrast-to-noise ratios, and coefficients of variation were
comparatively evaluated using parametric tests. Clinical radiologists (n=3)
assessed diagnostic quality as a function of sequence and anatomic structure
using 5-point Likert scales and ordinal regression. The significance level was
set to {\alpha}=0.01.
Results: MIX1 and MIX2 had at least equal diagnostic quality compared to the
2D and 3D TSE sequences of the same image weighting. Contrast,
contrast-to-noise ratios, and coefficients of variation were largely similar
for the PD-weighted FS and T1-weighted images.
Discussion: In clinically feasible scan times, the MIXTURE sequence platform
yields (i) morphologic images of diagnostic quality and adjustable TSE-based
contrasts and (ii) quantitative parameter mapping with additional insights on
soft tissue composition and ultrastructure.Comment: 13 pages (main text), 7 figures, 3 table
Forward Genetic Analysis of the Apicomplexan Cell Division Cycle in Toxoplasma gondii
Apicomplexa are obligate intracellular pathogens that have fine-tuned their proliferative strategies to match a large variety of host cells. A critical aspect of this adaptation is a flexible cell cycle that remains poorly understood at the mechanistic level. Here we describe a forward genetic dissection of the apicomplexan cell cycle using the Toxoplasma model. By high-throughput screening, we have isolated 165 temperature sensitive parasite growth mutants. Phenotypic analysis of these mutants suggests regulated progression through the parasite cell cycle with defined phases and checkpoints. These analyses also highlight the critical importance of the peculiar intranuclear spindle as the physical hub of cell cycle regulation. To link these phenotypes to parasite genes, we have developed a robust complementation system based on a genomic cosmid library. Using this approach, we have so far complemented 22 temperature sensitive mutants and identified 18 candidate loci, eight of which were independently confirmed using a set of sequenced and arrayed cosmids. For three of these loci we have identified the mutant allele. The genes identified include regulators of spindle formation, nuclear trafficking, and protein degradation. The genetic approach described here should be widely applicable to numerous essential aspects of parasite biology
Testing gravitational-wave searches with numerical relativity waveforms: Results from the first Numerical INJection Analysis (NINJA) project
The Numerical INJection Analysis (NINJA) project is a collaborative effort
between members of the numerical relativity and gravitational-wave data
analysis communities. The purpose of NINJA is to study the sensitivity of
existing gravitational-wave search algorithms using numerically generated
waveforms and to foster closer collaboration between the numerical relativity
and data analysis communities. We describe the results of the first NINJA
analysis which focused on gravitational waveforms from binary black hole
coalescence. Ten numerical relativity groups contributed numerical data which
were used to generate a set of gravitational-wave signals. These signals were
injected into a simulated data set, designed to mimic the response of the
Initial LIGO and Virgo gravitational-wave detectors. Nine groups analysed this
data using search and parameter-estimation pipelines. Matched filter
algorithms, un-modelled-burst searches and Bayesian parameter-estimation and
model-selection algorithms were applied to the data. We report the efficiency
of these search methods in detecting the numerical waveforms and measuring
their parameters. We describe preliminary comparisons between the different
search methods and suggest improvements for future NINJA analyses.Comment: 56 pages, 25 figures; various clarifications; accepted to CQ
The genomic and transcriptional landscape of primary central nervous system lymphoma
Primary lymphomas of the central nervous system (PCNSL) are mainly diffuse large B-cell lymphomas (DLBCLs) confined to the central nervous system (CNS). Molecular drivers of PCNSL have not been fully elucidated. Here, we profile and compare the whole-genome and transcriptome landscape of 51 CNS lymphomas (CNSL) to 39 follicular lymphoma and 36 DLBCL cases outside the CNS. We find recurrent mutations in JAK-STAT, NFkB, and B-cell receptor signaling pathways, including hallmark mutations in MYD88 L265P (67%) and CD79B (63%), and CDKN2A deletions (83%). PCNSLs exhibit significantly more focal deletions of HLA-D (6p21) locus as a potential mechanism of immune evasion. Mutational signatures correlating with DNA replication and mitosis are significantly enriched in PCNSL. TERT gene expression is significantly higher in PCNSL compared to activated B-cell (ABC)-DLBCL. Transcriptome analysis clearly distinguishes PCNSL and systemic DLBCL into distinct molecular subtypes. Epstein-Barr virus (EBV)+ CNSL cases lack recurrent mutational hotspots apart from IG and HLA-DRB loci. We show that PCNSL can be clearly distinguished from DLBCL, having distinct expression profiles, IG expression and translocation patterns, as well as specific combinations of genetic alterations
Expansion of the Multi-Link Frontier™ Coronary Bifurcation Stent: Micro-Computed Tomographic Assessment in Human Autopsy and Porcine Heart Samples
BACKGROUND: Treatment of coronary bifurcation lesions remains challenging, beyond the introduction of drug eluting stents. Dedicated stent systems are available to improve the technical approach to the treatment of these lesions. However dedicated stent systems have so far not reduced the incidence of stent restenosis. The aim of this study was to assess the expansion of the Multi-Link (ML) Frontier™ stent in human and porcine coronary arteries to provide the cardiologist with useful in-vitro information for stent implantation and selection. METHODOLOGY/PRINCIPAL FINDINGS: Nine ML Frontier™ stents were implanted in seven human autopsy heart samples with known coronary artery disease and five ML Frontier™ stents were implanted in five porcine hearts. Proximal, distal and side branch diameters (PD, DD, SBD, respectively), corresponding opening areas (PA, DA, SBA) and the mean stent length (L) were assessed by micro-computed tomography (micro-CT). PD and PA were significantly smaller in human autopsy heart samples than in porcine heart samples (3.54±0.47 mm vs. 4.04±0.22 mm, p = 0.048; 10.00±2.42 mm(2) vs. 12.84±1.38 mm(2), p = 0.034, respectively) and than those given by the manufacturer (3.54±0.47 mm vs. 4.03 mm, p = 0.014). L was smaller in human autopsy heart samples than in porcine heart samples, although data did not reach significance (16.66±1.30 mm vs. 17.30±0.51 mm, p = 0.32), and significantly smaller than that given by the manufacturer (16.66±1.30 mm vs. 18 mm, p = 0.015). CONCLUSIONS/SIGNIFICANCE: Micro-CT is a feasible tool for exact surveying of dedicated stent systems and could make a contribution to the development of these devices. The proximal diameter and proximal area of the stent system were considerably smaller in human autopsy heart samples than in porcine heart samples and than those given by the manufacturer. Special consideration should be given to the stent deployment procedure (and to the follow-up) of dedicated stent systems, considering final intravascular ultrasound or optical coherence tomography to visualize (and if necessary optimize) stent expansion
The genomic and transcriptional landscape of primary central nervous system lymphoma
Primary lymphomas of the central nervous system (PCNSL) are mainly diffuse large B-cell lymphomas (DLBCLs) confined to the central nervous system (CNS). Molecular drivers of PCNSL have not been fully elucidated. Here, we profile and compare the whole-genome and transcriptome landscape of 51 CNS lymphomas (CNSL) to 39 follicular lymphoma and 36 DLBCL cases outside the CNS. We find recurrent mutations in JAK-STAT, NFkB, and B-cell receptor signaling pathways, including hallmark mutations in MYD88 L265P (67%) and CD79B (63%), and CDKN2A deletions (83%). PCNSLs exhibit significantly more focal deletions of HLA-D (6p21) locus as a potential mechanism of immune evasion. Mutational signatures correlating with DNA replication and mitosis are significantly enriched in PCNSL. TERT gene expression is significantly higher in PCNSL compared to activated B-cell (ABC)-DLBCL. Transcriptome analysis clearly distinguishes PCNSL and systemic DLBCL into distinct molecular subtypes. Epstein-Barr virus (EBV)+ CNSL cases lack recurrent mutational hotspots apart from IG and HLA-DRB loci. We show that PCNSL can be clearly distinguished from DLBCL, having distinct expression profiles, IG expression and translocation patterns, as well as specific combinations of genetic alterations
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