1,408 research outputs found

    Visibility of technology and cumulative innovation: evidence from trade secrets laws

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    We use exogenous variation in the strength of trade secrets protection to show that a relative weakening of patents (compared to trade secrets) has a disproportionately negative effect on the disclosure of processes – inventions that are not otherwise visible to society. We develop a structural model of initial and follow-on innovation to determine the effects of such a shift in disclosure on overall welfare in industries characterized by cumulative innovation. We find that while stronger trade secrets encourage investment in R&D, they may have negative e�ects on overall welfare – the result of a significant decline in follow-on innovation

    OPTICAL COHERENCE TOMOGRAPHY IMAGING TO EVALUATE CAROTID ARTERY STENTS: SAFETY, FEASIBILITY, AND TECHNIQUE

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    Potential importance of physiologically diverse benthic foraminifera in sedimentary nitrate storage and respiration

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    Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 117 (2012): G03002, doi:10.1029/2012JG001949.Until recently, the process of denitrification (conversion of nitrate or nitrite to gaseous products) was thought to be performed exclusively by prokaryotes and fungi. The finding that foraminifera perform complete denitrification could impact our understanding of nitrate removal in sediments as well as our understanding of eukaryotic respiration, especially if it is widespread. However, details of this process and the subcellular location of these reactions in foraminifera remain uncertain. For example, prokaryotic endobionts, rather than the foraminifer proper, could perform denitrification, as has been shown recently in an allogromiid foraminifer. Here, intracellular nitrate concentrations and isotope ratios (δ15NNO3 and δ18ONO3) were measured to assess the nitrate dynamics in four benthic foraminiferal species (Bolivina argentea, Buliminella tenuata, Fursenkoina cornuta, Nonionella stella) with differing cellular architecture and associations with microbial endobionts, recovered from Santa Barbara Basin, California. Cellular nitrate concentrations were high (12–217 mM) in each species, and intracellular nitrate often had elevated δ15NNO3 and δ18ONO3 values. Experiments including suboxic and anoxic incubations of B. argentea revealed a decrease in intracellular nitrate concentration and an increase in δ15NNO3 and δ18ONO3 over time, indicating nitrate respiration and/or denitrification within the foraminifera. Results illustrate that nitrate reduction occurs in a range of foraminiferal species, including some possessing endobionts (including a chloroplast-sequestering species) and others lacking endobionts, implying that microbial associates may not solely be responsible for this process in foraminifera. Furthermore, we show that benthic foraminifera may represent important reservoirs of nitrate storage in sediments, as well as mediators of its removal.This research was supported by NSF grant EF-0702491 to JMB, KLC, and VPE.2013-01-0

    Specific characteristics of STEMI in COVID-19 patients and their practical implications

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    ST-elevation myocardial infarction (STEMI) is one of the cardiac emergencies whose management has been most challenged by the COVID-19 pandemic. Patients presenting with the “lethal combo” of STEMI and concomitant SARS-CoV-2 infection have faced dramatic issues related to the need for self-isolation, systemic inflammation with multi-organ disease and difficulties to obtain timely diagnosis and treatment. The interplay between these and other factors has partly neutralized the major advances in STEMI care achieved in the last decades, significantly impairing prognosis in these patients. In the present review article, we will provide an overview on mechanisms of myocardial injury, specific clinical and angiographic characteristics and contemporary management in different settings of STEMI patients with COVID-19, alongside the inherent implications in terms of in-hospital mortality and short-term clinical outcomes

    How to predict conduction disturbances after transcatheter aortic valve replacement?

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    Transcatheter aortic valve replacement (TAVI) has evolved into the gold standard management option for high-risk patients with severe aortic stenosis. Despite procedural, electrocardiographic and clinical predictors of important post-procedural conduction disturbances (left bundle branch block [LBBB] and high-degree atrioventricular block [HAVB]) being identified, and continuous technological refinement of transcatheter aortic valves, the rate of post-procedural conduction disturbance remains high, and challenging to manage. New strategies are required to reduce the overall rate of post-procedural PPI. In this article, we will review the incidence, predictive factors, and clinical implications of conduction disturbances after TAVI

    Association Between Colchicine Treatment and Clinical Outcomes in Patients with Coronary Artery Disease: Systematic Review and Meta-analysis

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    Background: The authors examined the association between colchicine treatment and clinical outcomes in patients with coronary artery disease. Methods: They performed a meta-analysis of randomised controlled trials (RCTs) involving patients with coronary artery disease receiving add-on colchicine to standard treatment compared with standard treatment. They used a mixed-effects Poisson regression model with random intervention effects to estimate the pooled incidence rate ratios (IRR) with 95% CI. Results: Ten RCTs were identified, including 12,819 participants followed up for a median of 6 months. Colchicine was associated with a lower risk of major adverse cardiovascular events (IRR 0.69; 95% CI [0.60–0.79]; number needed to treat for an additional beneficial outcome [NNTB] = 28); MI (IRR 0.77; 95% CI [0.64–0.93]; NNTB = 95) and ischaemic stroke (IRR 0.48; 95% CI [0.30–0.76]; NNTB = 155) and with a higher risk of gastrointestinal adverse events (IRR 1.69; 95% CI [1.12–2.54]; number needed to treat for an additional harmful outcome [NNTH] = 10). Colchicine did not affect all-cause death (IRR 1.09; 95% CI [0.85–1.40]), or cardiovascular death (IRR 0.75; 95% CI [0.51–1.12]), while it was associated with a higher risk of non-cardiovascular death (IRR 1.45; 95% CI [1.04–2.02]; NNTH = 396). Conclusion: The meta-analysis showed that the relative and absolute beneficial treatment effects of colchicine on cardiovascular outcomes outweigh the potential harm for non-cardiovascular mortality. Registration: PROSPERO 2021 CRD42021248874

    Green's function approach to the magnetic properties of the kagome antiferromagnet

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    The S=1/2S=1/2 Heisenberg antiferromagnet is studied on the kagom\'e lattice by using a Green's function method based on an appropriate decoupling of the equations of motion. Thermodynamic properties as well as spin-spin correlation functions are obtained and characterize this system as a two-dimensional quantum spin liquid. Spin-spin correlation functions decay exponentially with distance down to low temperature and the calculated missing entropy at T=0 is found to be 0.46ln20.46\ln{2}. Within the present scheme, the specific heat exhibits a single peak structure and a T2T^2 dependence at low temperature.Comment: 6 (two-column revtex4) pages, 5 ps figures. Submitted to Phys. Rev.

    Denitrification likely catalyzed by endobionts in an allogromiid foraminifer

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    Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in The ISME Journal 6 (2012): 951–960, doi:10.1038/ismej.2011.171.Nitrogen can be a limiting macronutrient for carbon uptake by the marine biosphere. The process of denitrification (conversion of nitrate to gaseous compounds, including N2) removes bioavailable nitrogen, particularly in marine sediments, making it a key factor in the marine nitrogen budget. Benthic foraminifera reportedly perform complete denitrification, a process previously considered nearly exclusively performed by bacteria and archaea. If the ability to denitrify is widespread among these diverse and abundant protists, a paradigm shift is required for biogeochemistry and marine microbial ecology. However, to date, the mechanisms of foraminiferal denitrification are unclear and it is possible that the ability to perform complete denitrification is due to symbiont metabolism in some foraminiferal species. Using sequence analysis and GeneFISH, we show that for a symbiont-bearing foraminifer, the potential for denitrification resides in the endobionts. Results also identify the endobionts as denitrifying pseudomonads and show that the allogromiid accumulates nitrate intracellularly, presumably for use in denitrification. Endobionts have been observed within many foraminiferal species, and in the case of associations with denitrifying bacteria, may provide fitness for survival in anoxic conditions. These associations may have been a driving force for early foraminiferal diversification, which is thought to have occurred in the Neoproterozoic when anoxia was widespread.This research was supported by NSF grant EF-0702491 to JMB, KLC and VPE; some ship support was provided by NSF MCB-0604084 to VPE and JMB.2012-06-0
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