1,522 research outputs found

    Fitting Jump Models

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    We describe a new framework for fitting jump models to a sequence of data. The key idea is to alternate between minimizing a loss function to fit multiple model parameters, and minimizing a discrete loss function to determine which set of model parameters is active at each data point. The framework is quite general and encompasses popular classes of models, such as hidden Markov models and piecewise affine models. The shape of the chosen loss functions to minimize determine the shape of the resulting jump model.Comment: Accepted for publication in Automatic

    Shaping the formation of university-industry research collaborations: what type of proximity does really matter?

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    Research collaborations between universities and industry (U-I) are considered to be one important channel of potential localized knowledge spillovers (LKS). These collaborations favour both intended and unintended flows of knowledge and facilitate learning processes between partners from different organizations. Despite the copious literature on LKS, still little is known about the factors driving the formation of U-I research collaborations and, in particular, about the role that geographical proximity plays in the establishment of such relationships. Using collaborative research grants between universities and business firms awarded by the UK Engineering and Physical Sciences Research Council (EPSRC), in this article we disentangle some of the conditions under which different kinds of proximity contribute to the formation of U-I research collaborations, focusing in particular on clustering and technological complementarity among the firms participating in such partnerships

    Knowledge Spillovers and Local Innovation Systems: A Critical Survey

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    Maternal mortality in 19th- and early 20th-century Italy

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    Although dramatically reduced in Western and developed countries, maternal mortality is still today one of the most relevant social and health scourges in developing countries. This is the reason why high levels of maternal mortality are always interpreted as a sign of low living standards, ignorance, poverty and woman discrimination. Maternal mortality represents, therefore, a very peculiar characteristic of demographic systems of ancien regime. Despite this important role in demographic systems, no systematic study has been addressed to investigate the impact of maternal mortality in historical Italy. The aim of this article is to shed some light on such a phenomenon by investigating its trend over time and the determinants in some Italian populations between the 18th and the early 20th centuries. The analysis will make use of civil and parish registers linked together by means of nominative techniques, and it will be, therefore, carried out at the micro level

    Zirconia-reinforced lithium silicate (ZLS) mechanical and biological properties: A literature review

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    Objectives: This paper aimed to provide a literature review of the mechanical and biological properties of zirconia-reinforced lithium silicate glass-ceramics (ZLS) in Computer-aided design / Computer-aided manufacturing (CAD/CAM) systems. Data/Sources: An extensive search of the literature for papers related to ZLS was made on the databases of PubMed/Medline, Scopus, Embase, Google Scholar, Dynamed, and Open Grey. The papers were selected by 3 independent calibrated reviewers. Study selection: The search strategy produced 937 records. After the removal of duplicates and the exclusion of papers that did not meet the inclusion criteria, 71 papers were included. Conclusions: After reviewing the included records, it was found that two types of ZLS (Vita Suprinity PC; Vita Zahnfabrik and Celtra Duo; Dentsply Sirona) are nowadays available on the market for CAD/CAM systems, similar in their chemical composition, microstructure, and biological-mechanical properties. ZLS is reported to be a biocompatible material, whose fracture resistance can withstand physiological chewing loads. The firing process influences the improvements of strength and fatigue failure load, with a volumetric shrinkage. To date, ZLS can be considered a viable alternative to other glass-ceramics for fixed single restorations. Clinical Significance:. As to biocompatibility and mechanical properties of ZLS, data are still scarce, often controversial and limited to short-term observational periods. These promising ceramics require further in vitro/in vivo studies to accurately define mechanical and biological properties, mainly in the long-term performance of restorations produced with such materials

    Collagen degradation by host-derived enzymes during aging

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    Incompletely infiltrated collagen fibrils in acid-etched dentin are susceptible to degradation. We hypothesize that degradation can occur in the absence of bacteria. Partially demineralized collagen matrices (DCMs) prepared from human dentin were stored in artificial saliva. Control specimens were stored in artificial saliva containing proteolytic enzyme inhibitors, or pure mineral oil. We retrieved them at 24 hrs, 90 and 250 days to examine the extent of degradation of DCM. In the 24-hour experimental and 90- and 250-day control specimens, we observed 5- to 6-μm-thick layers of DCM containing banded collagen fibrils. DCMs were almost completely destroyed in the 250-day experimental specimens, but not when incubated with enzyme inhibitors or mineral oil. Functional enzyme analysis of dentin powder revealed low levels of collagenolytic activity that was inhibited by protease inhibitors or 0.2% chlorhexidine. We hypothesize that collagen degradation occurred over time, via host-derived matrix metalloproteinases that are released slowly over time.published_or_final_versio

    Detectability of QCD phase transitions in binary neutron star mergers: Bayesian inference with the next generation gravitational wave detectors

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    We study the detectability of postmerger QCD phase transitions in neutron star binaries with next-generation gravitational-wave detectors Cosmic Explorer and Einstein Telescope. We perform numerical relativity simulations of neutron star mergers with equations of state that include a quark deconfinement phase transition through either a Gibbs or Maxwell construction. These are followed by Bayesian parameter estimation of the associated gravitational-wave signals using the NRPMw\tt{NRPMw} waveform model, with priors inferred from the analysis of the inspiral signal. We assess the ability of the model to measure the postmerger peak frequency f2peakf_2^{\rm peak} and identify aspects that should be improved in the model. We show that, even at postmerger signal to noise ratios as low as 10, the model can distinguish (at the 90% level) f2peakf_2^{\rm peak} between binaries with and without a phase transition in most cases. Phase-transition induced deviations in the f2peakf_2^{\rm peak} from the predictions of equation-of-state insensitive relations can also be detected if they exceed 1.6 σ1.6\,\sigma. Our results suggest that next-generation gravitational wave detectors can measure phase transition effects in binary neutron star mergers. However, unless the phase transition is ``strong'', disentangling it from other hadronic physics uncertainties will require significant theory improvements

    Identification of plasma microRNAs as new potential biomarkers with high diagnostic power in human cutaneous melanoma

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    Melanoma is a devastating disease with few therapeutic options in the advanced stage and with the urgent need of reliable biomarkers for early detection. In this context, circulating microRNAs are raising great interest as diagnostic biomarkers. We analyzed the expression profiles of 21 selected microRNAs in plasma samples from melanoma patients and healthy donors to identify potential diagnostic biomarkers. Data analysis was performed using global mean normalization and NormFinder algorithm. Linear regression followed by receiver operating characteristic analyses was carried out to evaluate whether selected plasma miRNAs were able to discriminate between cases and controls. We found five microRNAs that were differently expressed among cases and controls after Bonferroni correction for multiple testing. Specifically, miR-15b-5p, miR-149-3p, and miR-150-5p were up-regulated in plasma of melanoma patients compared with healthy controls, while miR-193a-3p and miR-524-5p were down-regulated. Receiver operating characteristic analyses of these selected microRNAs provided area under the receiver operating characteristic curve values ranging from 0.80 to 0.95. Diagnostic value of microRNAs is improved when considering the combination of miR-149-3p, miR-150-5p, and miR-193a-3p. The triple classifier had a high capacity to discriminate between melanoma patients and healthy controls, making it suitable to be used in early melanoma diagnosis
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