261 research outputs found
Contribution to the Diffuse Radio Background from Extragalactic Radio Sources
We examine the brightness of the Cosmic Radio Background (CRB) by comparing
the contribution from individual source counts to absolute measurements. We use
a compilation of radio counts to estimate the contribution of detected sources
to the CRB in several different frequency bands.We apply a Monte Carlo Markov
Chain technique to estimate the brightness values and uncertainties, paying
attention to various sources of systematic error. We compare our results to
absolute measurements from the ARCADE 2 experiment. At v = 150 MHz, 325 MHz,
408 MHz, 610 MHz, 1.4 GHz, 4.8 GHz, and 8.4 GHz our calculated contributions to
the background sky temperature are 18, 2.8, 1.6, 0.71, 0.11, 0.0032, 0.0059 K,
respectively. If the ARCADE 2 measurements are correct and come from sources,
then there must be an additional population of radio galaxies, fainter than
where current data are probing. More specifically, the Euclidean-normalized
counts at 1.4 GHz have to have an additional bump below about 10 {\mu}Jy.Comment: 9 pages, 7 figures, 3 tables, accepted MNRA
FastJet user manual
FastJet is a C++ package that provides a broad range of jet finding and
analysis tools. It includes efficient native implementations of all widely used
2-to-1 sequential recombination jet algorithms for pp and e+e- collisions, as
well as access to 3rd party jet algorithms through a plugin mechanism,
including all currently used cone algorithms. FastJet also provides means to
facilitate the manipulation of jet substructure, including some common boosted
heavy-object taggers, as well as tools for estimation of pileup and
underlying-event noise levels, determination of jet areas and subtraction or
suppression of noise in jets.Comment: 69 pages. FastJet 3 is available from http://fastjet.fr
High hospital research participation and improved colorectal cancer survival outcomes: a population-based study
Objective: In 2001, the National Institute for Health Research (NIHR) Cancer Research Network (NCRN) was established, leading to a rapid increase in clinical research activity across the English NHS. Using colorectal cancer (CRC) as an example, we test the hypothesis that high, sustained hospital-level participation in interventional clinical trials improves outcomes for all CRC patients managed in those research-intensive hospitals.
Design: Data for patients diagnosed with CRC in England in 2001-2008 (n=209,968) were linked with data on accrual to NCRN CRC studies (n=30,998). Hospital Trusts were categorised by the proportion of patients accrued to interventional studies annually. Multivariable models investigated the relationship between 30-day post-operative mortality and five-year survival and the level and duration of study participation.
Results: Most of the Trusts achieving high participation were district general hospitals and the effects were not limited to cancer “centres of excellence”, although such centres do make substantial contributions. Patients treated in Trusts with high research participation (≥16%) in their year of diagnosis had lower post-operative mortality (p<0.001) and improved survival (p<0.001) after adjustment for casemix and hospital-level variables. The effects increased with sustained research participation, with a reduction in post-operative mortality of 1.5% (6.5% to 5%, p<2.2*10-6) and an improvement in survival (p<10 19; 5-year difference: 3.8% (41.0% to 44.8%)) comparing high participation for ≥4 years with 0 years.
Conclusion: There is a strong independent association between survival and participation in interventional clinical studies for all CRC patients treated in the hospital, not only study participants. Improvement precedes and increases with the level and years of sustained participation
Ernst Freund as Precursor of the Rational Study of Corporate Law
Gindis, David, Ernst Freund as Precursor of the Rational Study of Corporate Law (October 27, 2017). Journal of Institutional Economics, Forthcoming. Available at SSRN: https://ssrn.com/abstract=2905547, doi: https://dx.doi.org/10.2139/ssrn.2905547The rise of large business corporations in the late 19th century compelled many American observers to admit that the nature of the corporation had yet to be understood. Published in this context, Ernst Freund's little-known The Legal Nature of Corporations (1897) was an original attempt to come to terms with a new legal and economic reality. But it can also be described, to paraphrase Oliver Wendell Holmes, as the earliest example of the rational study of corporate law. The paper shows that Freund had the intuitions of an institutional economist, and engaged in what today would be called comparative institutional analysis. Remarkably, his argument that the corporate form secures property against insider defection and against outsiders anticipated recent work on entity shielding and capital lock-in, and can be read as an early contribution to what today would be called the theory of the firm.Peer reviewe
The effect of adenosine monophosphate deaminase overexpression on the accumulation of umami-related metabolites in tomatoes
Taste is perceived as one of a combination of five sensations, sweet, sour, bitter, salty, and umami. The umami taste is best known as a savoury sensation and plays a central role in food flavour, palatability, and eating satisfaction. Umami flavour can be imparted by the presence of glutamate and is greatly enhanced by the addition of ribonucleotides, such as inosine monophosphate (IMP) and guanosine monophosphate (GMP). The production of IMP is regulated by the enzyme adenosine monophosphate (AMP) deaminase which functions to convert AMP into IMP. We have generated transgenic tomato (Solanum lycopersicum) lines over expressing AMP deaminase under the control of a fruit-specific promoter. The transgenic lines showed substantially enhanced levels of AMP deaminase expression in comparison to the wild-type control. Elevated AMP deaminase levels resulted in the reduced accumulation of glutamate and increased levels of the umami nucleotide GMP. AMP concentrations were unchanged. The effects on the levels of glutamate and GMP were unexpected and are discussed in relation to the metabolite flux within this pathway
Fully transformer-based biomarker prediction from colorectal cancer histology: a large-scale multicentric study
Background: Deep learning (DL) can extract predictive and prognostic
biomarkers from routine pathology slides in colorectal cancer. For example, a
DL test for the diagnosis of microsatellite instability (MSI) in CRC has been
approved in 2022. Current approaches rely on convolutional neural networks
(CNNs). Transformer networks are outperforming CNNs and are replacing them in
many applications, but have not been used for biomarker prediction in cancer at
a large scale. In addition, most DL approaches have been trained on small
patient cohorts, which limits their clinical utility. Methods: In this study,
we developed a new fully transformer-based pipeline for end-to-end biomarker
prediction from pathology slides. We combine a pre-trained transformer encoder
and a transformer network for patch aggregation, capable of yielding single and
multi-target prediction at patient level. We train our pipeline on over 9,000
patients from 10 colorectal cancer cohorts. Results: A fully transformer-based
approach massively improves the performance, generalizability, data efficiency,
and interpretability as compared with current state-of-the-art algorithms.
After training on a large multicenter cohort, we achieve a sensitivity of 0.97
with a negative predictive value of 0.99 for MSI prediction on surgical
resection specimens. We demonstrate for the first time that resection
specimen-only training reaches clinical-grade performance on endoscopic biopsy
tissue, solving a long-standing diagnostic problem. Interpretation: A fully
transformer-based end-to-end pipeline trained on thousands of pathology slides
yields clinical-grade performance for biomarker prediction on surgical
resections and biopsies. Our new methods are freely available under an open
source license
Genetic improvement of tomato by targeted control of fruit softening
Controlling the rate of softening to extend shelf life was a key target for researchers engineering genetically modified (GM) tomatoes in the 1990s, but only modest improvements were achieved. Hybrids grown nowadays contain 'non-ripening mutations' that slow ripening and improve shelf life, but adversely affect flavor and color. We report substantial, targeted control of tomato softening, without affecting other aspects of ripening, by silencing a gene encoding a pectate lyase
The Death and Rebirth of a Party System, Peru 1978-2001
This article evaluates structural, institutional, and actor-centered explanations of the collapse of the Peruvian party system around 1990 and its surprising partial recovery in 2001. It begins by describing the changes in the dependent variable, the emergence, collapse, and partial resurrection of the 1980s Peruvian party system. The next section examines the argument that the large size and rapid growth of the informal sector undermined the party system and led to its collapse. The author shows that the evidence does not support this argument. The article then examines changes in the electoral system. The author demonstrates that, contrary to theoretical expectations, the changes in the electoral system do not correlate with the observed changes in the party system. The final section shows that performance failure by political elites, including corruption in government, was more important than social cleavages or electoral institutions in the collapse and partial recovery of the party system.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
Rheumatoid arthritis and the role of oral bacteria
Rheumatoid arthritis (RA) and periodontal disease (PD) have shown similar physiopathologic mechanisms such as chronic inflammation with adjacent bone resorption in an immunogenetically susceptible host; however, PD has a well-recognized bacterial etiology while the cause of RA is unclear. Some reports have indicated that an infectious agent in a susceptible host could be one possible trigger factor for RA, and it has been suggested that oral microorganisms, specialty periodontal bacteria could be the infectious agent (mainly Porphyromonas gingivalis). It has been reported that PD is more frequent and more severe in patients with RA, suggesting a positive association between both diseases. There have been reports regarding the detection of antibodies against periodontal bacteria while other studies have identified periodontal bacterial DNA in serum and synovial fluid of RA patients and have explored the possible pathways of transport of periodontal bacterial DNA. In conclusion, there is no question that RA and PD have pathologic features in common and there is strong evidence of an association between both diseases, but further studies, including experimental models, are needed to demonstrate the arthritogenicity of oral microorganisms
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