927 research outputs found
Court Decisions and Equity Markets: Estimating the Value of Copyright Protection
We use a novel database on U. S. federal court decisions to measure the changes in the state of copyright protection in both statute and case law. We combine an index of copyright breadth derived from this database with a quarterly panel of firms in creative industries over the years 1986-1998. Using this data, we measure the impact of changes in the breadth of copyright on the market valuation of firm equity. We maintain the assumption that equity markets will incorporate the value of copyright innovations into the price of equity. After controlling for a variety of fundamental determinants of ÂŻrm-level excess returns to equity, we find that a court case broadening copyright is associated with a statistically significant 23-45 basis points increase in a firm's excess return. Our results obtain across both 4-5 year sub-samples and the size distribution of firms.
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Evaluation of uncomplicated acute respiratory tract infection management in veterans: A national utilization review.
BackgroundAntibiotics are overprescribed for acute respiratory tract infections (ARIs). Guidelines provide criteria to determine which patients should receive antibiotics. We assessed congruence between documentation of ARI diagnostic and treatment practices with guideline recommendations, treatment appropriateness, and outcomes.MethodsA multicenter quality improvement evaluation was conducted in 28 Veterans Affairs facilities. We included visits for pharyngitis, rhinosinusitis, bronchitis, and upper respiratory tract infections (URI-NOS) that occurred during the 2015-2016 winter season. A manual record review identified complicated cases, which were excluded. Data were extracted for visits meeting criteria, followed by analysis of practice patterns, guideline congruence, and outcomes.ResultsOf 5,740 visits, 4,305 met our inclusion criteria: pharyngitis (n = 558), rhinosinusitis (n = 715), bronchitis (n = 1,155), URI-NOS (n = 1,475), or mixed diagnoses (>1 ARI diagnosis) (n = 402). Antibiotics were prescribed in 68% of visits: pharyngitis (69%), rhinosinusitis (89%), bronchitis (86%), URI-NOS (37%), and mixed diagnosis (86%). Streptococcal diagnostic testing was performed in 33% of pharyngitis visits; group A Streptococcus was identified in 3% of visits. Streptococcal tests were ordered less frequently for patients who received antibiotics (28%) than those who did not receive antibiotics 44%; P < .01). Although 68% of visits for rhinosinusitis had documentation of symptoms, only 32% met diagnostic criteria for antibiotics. Overall, 39% of patients with uncomplicated ARIs received appropriate antibiotic management. The proportion of 30-day return visits for ARI care was similar for appropriate (11%) or inappropriate (10%) antibiotic management (P = .22).ConclusionsAntibiotics were prescribed in most uncomplicated ARI visits, indicating substantial overuse. Practice was frequently discordant with guideline diagnostic and treatment recommendations
A Search for High-Energy Counterparts to Fast Radio Bursts
We report on a search for high-energy counterparts to fast radio bursts
(FRBs) with the Fermi Gamma-ray Burst Monitor (GBM), Fermi Large Area Telescope
(LAT), and the Neil Gehrels Swift Observatory Burst Alert Telescope (BAT). We
find no significant associations for any of the 23 FRBs in our sample, but
report upper limits to the high-energy fluence for each on timescales of 0.1,
1, 10, and 100 s. We report lower limits on the ratio of the radio to
high-energy fluence, , for timescales of 0.1 and 100
s. We discuss the implications of our non-detections on various proposed
progenitor models for FRBs, including analogs of giant pulses from the Crab
pulsar and hyperflares from magnetars. This work demonstrates the utility of
analyses of high-energy data for FRBs in tracking down the nature of these
elusive sources
RAFT Aqueous Dispersion Polymerization of N -(2-(Methacryloyloxy)ethyl)pyrrolidone: A Convenient Low Viscosity Route to High Molecular Weight Water-Soluble Copolymers
RAFT solution polymerization of N-(2-(methacryoyloxy)ethyl)pyrrolidone (NMEP) in ethanol at 70 °C was conducted to produce a series of PNMEP homopolymers with mean degrees of polymerization (DP) varying from 31 to 467. Turbidimetry was used to assess their inverse temperature solubility behavior in dilute aqueous solution, with an LCST of approximately 55 °C being observed in the high molecular weight limit. Then a poly(glycerol monomethacylate) (PGMA) macro-CTA with a mean DP of 63 was chain-extended with NMEP using a RAFT aqueous dispersion polymerization formulation at 70 °C. The target PNMEP DP was systematically varied from 100 up to 6000 to generate a series of PGMA63âPNMEPx diblock copolymers. High conversions (â„92%) could be achieved when targeting up to x = 5000. GPC analysis confirmed high blocking efficiencies and a linear evolution in Mn with increasing PNMEP DP. A gradual increase in Mw/Mn was also observed when targeting higher DPs. However, this problem could be minimized (Mw/Mn < 1.50) by utilizing a higher purity grade of NMEP (98% vs 96%). This suggests that the broader molecular weight distributions observed at higher DPs are simply the result of a dimethacrylate impurity causing light branching, rather than an intrinsic side reaction such as chain transfer to polymer. Kinetic studies confirmed that the RAFT aqueous dispersion polymerization of NMEP was approximately four times faster than the RAFT solution polymerization of NMEP in ethanol when targeting the same DP in each case. This is perhaps surprising because both 1H NMR and SAXS studies indicate that the core-forming PNMEP chains remain relatively solvated at 70 °C in the latter formulation. Moreover, dissolution of the initial PGMA63âPNMEPx particles occurs on cooling from 70 to 20 °C as the PNMEP block passes through its LCST. Hence this RAFT aqueous dispersion polymerization formulation offers an efficient route to a high molecular weight water-soluble polymer in a rather convenient low-viscosity form. Finally, the relatively expensive PGMA macro-CTA was replaced with a poly(methacrylic acid) (PMAA) macro-CTA. High conversions were also achieved for PMAA85âPNMEPx diblock copolymers prepared via RAFT aqueous dispersion polymerization for x †4000. Again, better control was achieved when using the 98% purity NMEP monomer in such syntheses
Does α-synuclein have a dual and opposing effect in preclinical vs. clinical Parkinson's disease?
Abstractα-Synuclein gene (SNCA) multiplications cause familial parkinsonism and allele-length polymorphisms within the SNCA dinucleotide repeat REP1 increase the risk for developing Parkinson's disease (PD). Since SNCA multiplications increase SNCA expression, and REP1 genotypes that increase the risk of developing PD show increased SNCA expression in cell-culture systems, animal models, and human blood and brain, PD therapies seek to reduce SNCA expression. We conducted an observational study of 1098 PD cases to test the hypothesis that REP1 genotypes correlated with reduced SNCA expression are associated with better motor and cognitive outcomes. We evaluated the association of REP1 genotypes with survival free of Hoehn and Yahr stages 4 or 5 (motor outcome) and of Modified Telephone Interview for Cognitive Status score â€27 or Alzheimer's Disease Dementia Screening Interview score â„2 (cognitive outcome). Median disease duration at baseline was 3.3 years and median lag time from baseline to follow-up was 7.8 years. Paradoxically, REP1 genotypes associated with increased risk of developing PD and increased SNCA expression were associated with better motor (HR = 0.87, p = 0.046, covariate-adjusted age-scale analysis; HR = 0.85, p = 0.020, covariate-adjusted time-scale analysis) and cognitive outcomes (HR = 0.90, p = 0.12, covariate-adjusted age-scale analysis; HR = 0.85, p = 0.023, covariate-adjusted time-scale analysis). Our findings raise the possibility that SNCA has a dual, opposing, and time-dependent role. This may have implications for the development of therapies that target SNCA expression
Is there a causal relationship between acute stage sensorimotor cortex activity and the development of chronic low back pain? : a protocol and statistical analysis plan
Introduction: Why some people develop chronic pain following an acute episode of low back pain is unknown. Recent cross-sectional studies have suggested a relationship between aberrant sensorimotor cortex activity and pain persistence. The UPWaRD (Understanding persistent Pain Where it ResiDes) cohort study is the first prospective, longitudinal investigation of sensorimotor cortex activity in low back pain. This paper describes the development of a causal model and statistical analysis plan for investigating the causal effect of sensorimotor cortex activity on the development of chronic low back pain. Methods and analysis: Sensorimotor cortex activity was assessed within 6 weeks of low back pain onset using somatosensory evoked potentials and transcranial magnetic stimulation mapping techniques. Chronic low back pain is defined as ongoing pain (Numerical Rating score â„1) or disability (Roland Morris Disability Questionnaire score â„3) at 6âmonths follow-up. Variables that could confound the relationship between sensorimotor cortex activity and chronic low back pain were identified using a directed acyclic graph and content expertise was used to specify known causal paths. The statistical model was developed âa prioriâ to control for confounding variables identified in the directed acyclic graph, allowing an unbiased estimate of the causal effect of sensorimotor activity in acute low back pain on the development of chronic pain. The statistical analysis plan was finalised prior to follow-up of all participants and initiation of analysis. Ethics and dissemination: Ethical approval has been obtained from Western Sydney University Human Research Ethics Committee (H10465) and from Neuroscience Research Australia (SSA: 16/002). Dissemination will occur through presentations at national and international conferences and publications in international peer-reviewed journals. Trial registration number: ACTRN12619000002189 (retrospectively registered)
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