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Objective: To assess the methodological quality of radiomics-based models in endometrial cancer using the radiomics quality score (RQS) and METhodological radiomICs score (METRICS). Methods: We systematically reviewed studies published by October 30th, 2023. Inclusion criteria were original radiomics studies on endometrial cancer using CT, MRI, PET, or ultrasound. Articles underwent a quality assessment by novice and expert radiologists using RQS and METRICS. The inter-rater reliability for RQS and METRICS among radiologists with varying expertise was determined. Subgroup analyses were performed to assess whether scores varied according to study topic, imaging technique, publication year, and journal quartile. Results: Sixty-eight studies were analysed, with a median RQS of 11 (IQR, 9–14) and METRICS score of 67.6% (IQR, 58.8–76.0); two different articles reached maximum RQS of 19 and METRICS of 90.7%, respectively. Most studies utilised MRI (82.3%) and machine learning methods (88.2%). Characterisation and recurrence risk stratification were the most explored outcomes, featured in 35.3% and 19.1% of articles, respectively. High inter-rater reliability was observed for both RQS (ICC: 0.897; 95% CI: 0.821, 0.946) and METRICS (ICC: 0.959; 95% CI: 0.928, 0.979). Methodological limitations such as lack of external validation suggest areas for improvement. At subgroup analyses, no statistically significant difference was noted. Conclusions: Whilst using RQS, the quality of endometrial cancer radiomics research was apparently unsatisfactory, METRICS depicts a good overall quality. Our study highlights the need for strict compliance with quality metrics. Adhering to these quality measures can increase the consistency of radiomics towards clinical application in the pre-operative management of endometrial cancer. Clinical relevance statement: Both the RQS and METRICS can function as instrumental tools for identifying different methodological deficiencies in endometrial cancer radiomics research. However, METRICS also reflected a focus on the practical applicability and clarity of documentation. Key Points: The topic of radiomics currently lacks standardisation, limiting clinical implementation. METRICS scores were generally higher than the RQS, reflecting differences in the development process and methodological content. A positive trend in METRICS score may suggest growing attention to methodological aspects in radiomics research. [ABSTRACT FROM AUTHOR]

Agroecological farming is widely considered to reconcile improved working and living conditions of farmers while promoting social, economic, and ecological sustainability. However, most existing research primarily focuses on relatively narrow trade-offs between workload, economic and ecological outcomes at farm level and overlooks the critical role of contextual factors. This article conducts a critical literature review on the complex nature of agroecological farm work and proposes the holistic concept of sustainable farm work (SFW) in agroecology together with a heuristic evaluation framework. The latter was applied to ten case studies to test its relevance, affirming positive outcomes of agroecology on SFW, such as improved food sovereignty, biodiversity conservation, and social inclusiveness, but also showing trade-offs, including increased workload and potential yield reductions. Further, results show that contextual factors, such as policy support, market regulation, and access to resources, heavily influence the impact of agroecological practices on SFW. This article strongly argues for the importance of a holistic understanding of SFW and its contextualization within multiple socio-ecological system levels. The proposed framework establishes clear relationships between agroecology and SFW. An explicit recognition of these multidimensional relationships is essential for maximizing positive outcomes of agroecology in different contexts and fostering SFW. On a theoretical level, this research concludes that, from a holistic perspective, work is an entry point to studying the potential of agroecology to drive a sustainable agroecological transition in economic, social, and ecological terms. [ABSTRACT FROM AUTHOR]

The development of broad-spectrum coronavirus vaccines is essential to prepare for future respiratory virus pandemics. We demonstrated broad neutralization by a trivalent subunit vaccine, formulating the receptor-binding domains of SARS-CoV, MERS-CoV, and SARS-CoV-2 XBB.1.5 with Alum and CpG55.2. Vaccinated mice produced cross-neutralizing antibodies against all three human Betacoronaviruses and others currently exclusive to bats, indicating the epitope preservation of the individual antigens during co-formulation and the potential for epitope broadening. [ABSTRACT FROM AUTHOR]

Background and Objectives: Clinical manifestations of coronavirus disease 2019 (COVID-19) often persist after acute disease resolution. Underlying molecular mechanisms are unclear. The objective of this original article was to longitudinally measure plasma levels of markers of the innate immune response to investigate whether they associate with and predict post-COVID symptomatology. Methods: Adult patients with previous severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection during the first pandemic wave who underwent the 6-month multidisciplinary follow-up were included. Plasma levels of pentraxin 3 (PTX3), the complement components C3a and C5a, and chitinase-3 like-protein-1 (CHI3L1) were measured at hospital admission during acute disease (baseline) and at 1 and 6 months after hospital discharge. Associations with post-COVID-19 sequelae at 6 months were investigated using descriptive statistic and multiple regression models. Results: Ninety-four COVID-19 patients were included. Baseline PTX3, C5a, C3a, and CHI3L1 did not predict post-COVID-19 sequelae. The extent of the reduction of PTX3 over time (delta PTX3) was associated with lower depressive and anxiety symptoms at 6 months (both p < 0.05). When entering sex, age, need for intensive care unit or non-invasive ventilation during hospital stay, psychiatric history, and baseline PTX3 as nuisance covariates into a generalized linear model (GLM), the difference between baseline and 6-month PTX3 levels (delta PTX3) significantly predicted depression (χ2 = 4.66, p = 0.031) and anxiety (χ2 = 4.68, p = 0.031) at 6 months. No differences in PTX3 levels or PTX3 delta were found in patients with or without persistent or new-onset other COVID-19 symptoms or signs at 6 months. Plasma levels of C3a, C5a, and CHI3L1 did not correlate with PTX3 levels at either time point and failed to associate with residual or de novo respiratory or systemic clinical manifestations of the disease at 6 months. Conclusions: A lower reduction of plasma PTX3 after acute COVID-19 associates with the presence of depression and anxiety, suggesting an involvement of inflammation in post-COVID-19 psychopathology and a potential role of PTX3 as a biomarker. [ABSTRACT FROM AUTHOR]

Artificial intelligence (AI) has shown promise in various areas of oncology, but its clinical application in gynecologic oncologic imaging is still limited. AI algorithms can improve MRI acquisition times, reduce radiation dose in CT scans, and automate tumor segmentations. In endometrial cancer, AI can help identify imaging phenotypes that refine risk groups and tailor treatments. In cervical cancer, AI can predict lymph nodal status and treatment response. In ovarian cancer, AI can automate tumor segmentations and track tumor heterogeneity. However, AI tools still have limited generalizability and interpretability, and multidisciplinary collaboration is needed for successful implementation in clinical practice. [Extracted from the article]

Pain remains one of the most difficult-to-treat domains in patients with rheumatoid arthritis (RA). In clinical trials, the Janus kinase inhibitors (JAKis) have demonstrated good efficacy in pain relief. Aim of our study was to evaluate the real-life effectiveness of JAKis in improving pain in patients with RA in different states of baseline disease activity. A monocentric prospective cohort of 181 RA patients starting treatment with JAKis was studied. Pain was evaluated on a 0–100 mm visual analogue scale (VAS). Clinically meaningful improvements over 24 weeks were defined as follows: proportion of patients achieving ≥ 30%, ≥ 50%, and ≥ 70% pain relief, and remaining pain ≤ 20 or ≤ 10 mm. Results were analysed after stratification for baseline inflammatory activity; patients with swollen joints and C-reactive protein ≤ 1 at treatment start were considered pauci-inflammatory. Proportion of patients who achieved ≥ 30%, ≥ 50% and ≥ 70% pain improvement at 24 weeks was 61.4%, 49.3% and 32.9%. Furthermore, 40.6% and 28.5% of the patients achieved thresholds of remaining pain equivalent to mild pain or no/limited pain. Pain improvements were more evident in patients naive to previous biologics, although nearly 30% of multiple failures achieved VAS ≤ 20 mm. No significant differences were observed in relation to monotherapy. Pauci-inflammatory patients at treatment start achieved good outcomes, with 40.4% experiencing ≥ 70% pain improvement, and 35.7% VAS ≤ 10 mm. JAKis show efficacy in pain relief in real life. The improvement of painful symptoms also in those patients with limited objective inflammation may open new perspectives on the management of difficult-to-treat RA. [ABSTRACT FROM AUTHOR]

We introduce a new methodology to investigate the degree of persistence in firm growth dynamics, based on Conditional Quantile Transition Probability Matrices (CQTPMs) and exact inferential tests derived from two well-known mobility indexes. We apply the methodology to study manufacturing firms in the UK and four major European economies over the period 2010–2017. We find that CQTPMs display more persistence than under a fully independent firm growth process, albeit considerable turbulence and significant bouncing effects are detected. Exploiting the inferential statistics within a regression framework, we show that productivity, openness to trade, and business dynamism are the primary sources of firm growth persistence across sectors, while country-specific and time-specific factors play a second-order role. Plain English Summary: Use mobility indexes from CQTPMs to make precise inference about persistence in firm growth performance! This paper proposes a new method to measure the degree of persistence in the growth process of firms. Improving upon previous studies, we provide exact statistical inference and control for possible confounding factors. Application of our method to firm-level data on the UK and four major European economies, reveals a statistically significant, albeit small tendency of firms to repeat their past growth. However, we also observe considerable turbulence in the growth rates distribution over time. Persistence in growth is more strongly associated with sectoral characteristics such as productivity, business dynamism and trade openness, than with country-specific or time-specific factors. These findings pose interesting challenges to the theory. They also imply that policies addressed to foster growth in a specific group of firms are likely to have a volatile and transient effect. Our approach is flexible and suited for wide applicability in other domains of firm-level analysis. [ABSTRACT FROM AUTHOR]

The degree of uncertainty associated with the value of a company plays a relevant role in valuation analysis. We propose an original and robust methodology for company market valuation, which replaces the traditional point estimate of the conventional Discounted Cash Flow model with a probability distribution of fair values that convey information about both the expected value of the company and its intrinsic uncertainty. Our methodology depends on two main ingredients: an econometric model for company revenues and a set of firm-specific balance sheet relations that are estimated using historical data. We explore the effectiveness and scope of our methodology through a series of statistical exercises on publicly traded U.S. companies. At the firm level, we show that the fair value distribution derived with our methodology constitutes a reliable predictor of the company's future abnormal returns. At the market level, we show that a long-short valuation (LSV) factor, built using buy-sell recommendations based on the fair value distribution, contains information not accessible through the traditional market factors. The LSV factor significantly increases the explanatory and the predictive power of factor models estimated on portfolios and individual stock returns. [ABSTRACT FROM AUTHOR]

In the context of sports analytics, the evaluation of players’ performance has traditionally been a complex endeavor, given the multidimensional nature of the data involved. This paper introduces a novel approach for multivariate analyses of complex data sets, with a focus on professional basketball data. The proposed model simultaneously performs unsupervised classification of units into K clusters and their optimal low-dimensional reconstruction. This is done considering variables’ dimensionality representation into Q components for each group of clusters that can be identified by the same latent dimensions. Consequently, we refer to the new model as Generalized Reduced K-Means (GRKM), which includes RKM as a special case when a unique lower rank reconstruction of the variables is needed. Before the application on real data, the effectiveness of the proposal is shown by means of an extended simulation study. By applying this innovative method to a comprehensive set of National Basketball Association (NBA) statistics, we demonstrate its efficacy in distinguishing player profiles across offensive and defensive spectrums, simultaneously grouping them into coherent clusters. [ABSTRACT FROM AUTHOR]

Senegal is among the few African countries that counts with an important agroecological movement. This movement is strongly backed up by a network of transnational partnerships and has recently matured into an advocacy coalition that promotes an agroecological transition at national scale. In this article, we investigate the role of transnational links on the empowerment potential of agroecology. Combining the multi-level perspective of socio-technical transitions and Bourdieu's theory of practices, we conceptualize the agroecological network as a niche shaped by the circulation of different types of capital. Using social network analysis, we investigate the existing flows of resources and knowledge, as well as membership and advocacy links to critically address within-niche empowerment processes. We show that transnational ties play a key role in building the niche protective space, showing a financial dependency of the agroecological niche on NGOs and international cooperation programmes based in Europe and North America. This configuration tends to favor the empowerment of NGOs instead of farmer unions, which only play a peripheral role in the network. However, the multiple innovations focus of agroecology may open up prospects for more gradual but potentially radical change. Based on our findings, we suggest to include more explicitly core-periphery dynamics in transition studies involving North–South relations, including circulation of capital, ideas and norms. [ABSTRACT FROM AUTHOR]

We introduce a real-valued measure on non-Archimedean ordered fields that extend the field of real numbers . The definition of is inspired by the Loeb measures of hyperreal fields in the framework of Robinson's analysis with infinitesimals. The real-valued measure turns out to be general enough to obtain a canonical measurable representative in for every Lebesgue measurable subset of , moreover the measure of the two sets is equal. In addition, it is more expressive than a class of non-Archimedean uniform measures. We focus on the properties of the real-valued measure in the case where , the Levi-Civita field. In particular, we compare with the uniform non-Archimedean measure over developed by Shamseddine and Berz, and we prove that the first is infinitesimally close to the second, whenever the latter is defined. We also define a real-valued integral for functions on the Levi-Civita field, and we prove that every real continuous function has an integrable representative in . Recall that this result is false for the current non-Archimedean integration over . The paper concludes with a discussion on the representation of the Dirac distribution by pointwise functions on non-Archimedean domains. [ABSTRACT FROM AUTHOR]

In this paper, we establish several characterizations of the A-parallelism of bounded linear operators with respect to the seminorm induced by a positive operator A acting on a complex Hilbert space. Among other things, we investigate the relationship between A-seminorm-parallelism and A-Birkhoff–James orthogonality of A-bounded operators. In particular, we characterize A-bounded operators which satisfy the A-Daugavet equation. In addition, we relate the A-Birkhoff–James orthogonality of operators to the distance formulas and we give an explicit formula of the center mass for A-bounded operators. Some other related results are also discussed. [ABSTRACT FROM AUTHOR]

Background: The role of intravenous immunoglobulins (IVIG) during sepsis is controversial, as different trials on IVIG have observed inconsistent survival benefits. We aimed to elucidate the possible association and clinical significance between circulating levels of immunoglobulins. Methods: In a subset of 956 patients with severe sepsis and septic shock of the multicentre, open-label RCT ALBIOS, venous blood samples were serially collected 1, 2, and 7 days after enrolment (or at ICU discharge, whichever came first). IgA, IgG and IgM concentrations were assayed in all patients on day 1 and in a subgroup of 150 patients on days 2 and 7. Ig concentrations were measured employing a turbidimetric assay, OSR61171 system. Results: IgA on day 1 had a significant predictive value for both 28-day and 90-day mortality (28-day mortality, HR: 1.50 (95% CI 1.18–1.92); 90-day mortality, HR: 1.54 (95% CI 1.25–1.91)). IgG, but not IgM, on day 1 showed similar results for 28-day (HR 1.83 (95% CI 1.33–2.51) and 90-day mortality HR: 1.66 (95% CI 1.23–2.25)). In addition, lower levels of IgG but not of IgA and IgM, at day 1 were associated with significantly higher risk of secondary infections (533 [406–772] vs 600 [452–842] mg/dL, median [Q1–Q3], p = 0.007). Conclusions: In the largest cohort study of patients with severe sepsis or septic shock, we found that high levels of IgA and IgG on the first day of diagnosis were associated with a decreased 90-day survival. No association was found between IgM levels and survival. As such, the assessment of endogenous immunoglobulins could be a useful tool to identify septic patients at high risk of mortality. Trial registration #NCT00707122, Clinicaltrial.gov, registered 30 June 2008 [ABSTRACT FROM AUTHOR]

We prove that a Riemann-like integral on non-Archimedean extensions of cannot assign an integral to every function whose standard part is measurable and simultaneously satisfy the fundamental theorem of calculus. We also discuss how existing theories of non-Archimedean integration deal with the incompatibility of these conditions. [ABSTRACT FROM AUTHOR]

There is growing concern about seismicity triggered by human activities, whereby small increases in stress bring tectonically loaded faults to failure. Examples of such activities include mining, impoundment of water, stimulation of geothermal fields, extraction of hydrocarbons and water, and the injection of water, CO2 and methane into subsurface reservoirs1. In the absence of sufficient information to understand and control the processes that trigger earthquakes, authorities have set up empirical regulatory monitoring-based frameworks with varying degrees of success2,3. Field experiments in the early 1970s at the Rangely, Colorado (USA) oil field4 suggested that seismicity might be turned on or off by cycling subsurface fluid pressure above or below a threshold. Here we report the development, testing and implementation of a multidisciplinary methodology for managing triggered seismicity using comprehensive and detailed information about the subsurface to calibrate geomechanical and earthquake source physics models. We then validate these models by comparing their predictions to subsequent observations made after calibration. We use our approach in the Val d’Agri oil field in seismically active southern Italy, demonstrating the successful management of triggered seismicity using a process-based method applied to a producing hydrocarbon field. Applying our approach elsewhere could help to manage and mitigate triggered seismicity.A multidisciplinary method for managing triggered seismicity is developed using detailed subsurface information to calibrate geomechanical and earthquake source physics models, and is applied to the Val d’Agri oil field in seismically active southern Italy. [ABSTRACT FROM AUTHOR]

Serum amyloid P component (SAP, also known as Pentraxin 2; APCS gene) is a component of the humoral arm of innate immunity involved in resistance to bacterial infection and regulation of tissue remodeling. Here we investigate the role of SAP in antifungal resistance. Apcs−/− mice show enhanced susceptibility to A. fumigatus infection. Murine and human SAP bound conidia, activate the complement cascade and enhance phagocytosis by neutrophils. Apcs−/− mice are defective in vivo in terms of recruitment of neutrophils and phagocytosis in the lungs. Opsonic activity of SAP is dependent on the classical pathway of complement activation. In immunosuppressed mice, SAP administration protects hosts against A. fumigatus infection and death. In the context of a study of hematopoietic stem-cell transplantation, genetic variation in the human APCS gene is associated with susceptibility to invasive pulmonary aspergillosis. Thus, SAP is a fluid phase pattern recognition molecule essential for resistance against A. fumigatus. Serum Amyloid P is a humoral component with established roles in the response to bacterial infection and regulation of tissue remodeling. Here the authors provide evidence to a further crucial role of serum amyloid P in the context of fungal pathogen Aspergillus fumigatus. [ABSTRACT FROM AUTHOR]

A SARS-CoV-2 RBD219-N1C1 (RBD219-N1C1) recombinant protein antigen formulated on Alhydrogel® has recently been shown to elicit a robust neutralizing antibody response against SARS-CoV-2 pseudovirus in mice. The antigen has been produced under current good manufacturing practices (cGMPs) and is now in clinical testing. Here, we report on process development and scale-up optimization for upstream fermentation and downstream purification of the antigen. This includes production at the 1-L and 5-L scales in the yeast, Pichia pastoris, and the comparison of three different chromatographic purification methods. This culminated in the selection of a process to produce RBD219-N1C1 with a yield of >400 mg per liter of fermentation with >92% purity and >39% target product recovery after purification. In addition, we show the results from analytical studies, including SEC-HPLC, DLS, and an ACE2 receptor binding assay that were performed to characterize the purified proteins to select the best purification process. Finally, we propose an optimized upstream fermentation and downstream purification process that generates quality RBD219-N1C1 protein antigen and is fully scalable at a low cost. Key points: • Yeast fermentation conditions for a recombinant COVID-19 vaccine were determined. • Three purification protocols for a COVID-19 vaccine antigen were compared. • Reproducibility of a scalable, low-cost process for a COVID-19 vaccine was shown. Graphical abstract [ABSTRACT FROM AUTHOR]

Chagas disease resulting from Trypanosoma cruzi infection leads to a silent, long-lasting chronic neglected tropical disease affecting the poorest and underserved populations around the world. Antiparasitic treatment with benznidazole does not prevent disease progression or death in patients with established cardiac disease. Our consortium is developing a therapeutic vaccine based on the T. cruzi flagellar—derived antigen Tc24-C4 formulated with a Toll-like receptor 4 agonist adjuvant, to complement existing chemotherapy and improve treatment efficacy. Here we demonstrate that therapeutic treatment of acutely infected mice with a reduced dose of benznidazole concurrently with vaccine treatment – also known as "vaccine-linked chemotherapy"—induced a TH17 like immune response, with significantly increased production of antigen specific IL-17A, IL-23 and IL-22, and CD8 + T lymphocytes, as well as significantly increased T. cruzi specific IFNγ-producing CD4 + T lymphocytes. Significantly reduced cardiac inflammation, fibrosis, and parasite burdens and improved survival were achieved by vaccine-linked chemotherapy and individual treatments. Importantly, low dose treatments were comparably efficacious to high dose treatments, demonstrating potential dose sparing effects. We conclude that through induction of TH17 immune responses vaccine-linked chemotherapeutic strategies could bridge the tolerability and efficacy gaps of current drug treatment in Chagasic patients. [ABSTRACT FROM AUTHOR]

This study tests the hypothesis that an Onchocerca volvulus vaccine, consisting of two recombinant antigens (Ov-103 and Ov-RAL-2) formulated with the combination-adjuvant Advax-2, can induce protective immunity in genetically diverse Collaborative Cross recombinant inbred intercross mice (CC-RIX). CC-RIX lines were immunized with the O. volvulus vaccine and challenged with third-stage larvae. Equal and significant reductions in parasite survival were observed in 7 of 8 CC-RIX lines. Innate protective immunity was seen in the single CC-RIX line that did not demonstrate protective adaptive immunity. Analysis of a wide array of immune factors showed that each line of mice have a unique set of immune responses to vaccination and challenge suggesting that the vaccine is polyfunctional, inducing different equally-protective sets of immune responses based on the genetic background of the immunized host. Vaccine efficacy in genetically diverse mice suggests that it will also be effective in genetically complex human populations. [ABSTRACT FROM AUTHOR]

Pentraxin 3 (PTX3) is an acute phase protein; its plasmatic levels significantly rise during severe infections. Data on PTX3 levels in cerebrospinal fluid (CSF) of patients with central nervous system (CNS) infections are lacking. We aimed (a) to assess the diagnostic potential of measuring CSF PTX3 levels in patients with CNS infections and (b) to establish CSF PTX3 cutoffs to distinguish between bacterial and aseptic meningoencephalitis (ROC curve). PTX3 levels were measured in CSF from 19 patients admitted to Trieste Hospital, Italy, with CNS infection. A diagnosis of bacterial infection and aseptic meningoencephalitis was made in 7 (37%) and 12 (63%) patients, respectively. Subjects with bacterial infections showed significantly higher PTX3 levels (13.5 vs 1.27 ng/mL in aseptic meningoencephalitis, p = 0.010). We identified two different CSF PTX3 levels cutoffs. (1) The best cutoff to maximise Youden's J was 9.6 ng/mL with a sensitivity, specificity, positive predictive value and negative predictive value (NPV) of 71.4%, 91.4%, 83.3%, 84.6%, respectively. (2) The cutoff with higher NPV (100%) was 3.6 ng/mL; a diagnosis of bacterial infections was obtained in 0% patients with CSF PTX3 levels < 3.6 ng/mL vs 58% of those with CSF PTX3 levels ≥ 3.6 ng/mL (p = 0.017). CSF PTX3 levels are higher in bacterial meningitis than aseptic meningoencephalitis. A cutoff of 3.6 ng/mL of CSF PTX3 has a high NPV and can be used to exclude bacterial CNS infections. [ABSTRACT FROM AUTHOR]

Plant breeding programmes frequently face the dilemma whether to breed for wide or specific adaptation. This is especially true for forage crop breeding, whose genetic resources may largely include landraces that are adapted to specific growing conditions. This study aimed to (1) investigate the extent and pattern of genotype × location (GL) interaction for biomass yield of recent lucerne cultivars across organically-managed sites of Northern and Central Italy and its relationship with cultivar selection environments, (2) provide an empirical assessment of yield gains derived from specific-adaptation and wide-adaptation breeding strategies, and (3) identify top-performing cultivars for different geographic regions. Cultivar adaptive responses, modelled by additive main effects and multiplicative interaction analysis, displayed wide GL interaction of cross-over type across test sites that reflected remarkably the geographic area and/or the growing conditions (particularly for extent of summer drought) of their selection environment. GL interaction patterns suggested three putative subregions to breed for specific adaptation, namely, Northern Italy north of the Po river, Northern Italy south of the Po river, and Central Italy. Growing specifically-adapted cultivars provided an estimated average advantage of 12.9% across subregions relative to the best-performing widely-adapted cultivar. Yield gains of recent top-performing material over an historical, widely-adapted cultivar indicated that selection for specific adaptation would provide 3.2-fold greater yield gain averaged across subregions, and 3.4-fold greater yield gain over the target region when weighting yield gains on the putative proportion of the target region of each subregion, compared with selection for wide adaptation. [ABSTRACT FROM AUTHOR]

This paper investigates whether short-term momentum and long-term reversal may emerge from the wealth reallocation process taking place in speculative markets. We assume that there are two classes of investors who trade long-lived assets by holding constantly rebalanced portfolios based on their beliefs. Provided beliefs, and thus portfolios, are sufficiently diversified, all investors survive in the long-run and, due to waves of mispricing, the resulting equilibrium returns exhibit long-term reversal. If, moreover, asset dividends are positively correlated, investors' profitable trades become positively correlated too, thus generating short-term momentum in equilibrium returns. We use the model to replicate the performance of the Winners and Losers portfolios highlighted by the empirical literature and to provide insights on how to improve upon them. Finally, we show that dividend positive autocorrelation is positively related to momentum and negatively related to reversal while diversity of beliefs is positively related to both momentum and reversal. [ABSTRACT FROM AUTHOR]

We consider an exchange economy where agents have heterogeneous beliefs and assets are long-lived, and investigate the coupled dynamics of asset prices and agents’ wealth. We assume that agents hold fixed-mix portfolios and invest on each asset proportionally to its expected dividends. We prove the existence and uniqueness of a sequence of arbitrage-free market equilibrium prices and provide sufficient conditions for an agent, or a group of agents, to survive or dominate. Our main finding is that long-run coexistence of agents with heterogeneous beliefs, leading to asset prices endogenous fluctuations, is a generic outcome of the market selection process. [ABSTRACT FROM AUTHOR]

We discuss the properties of the continuations of real functions to the Levi-Civita field. In particular, we show that, whenever a function f is analytic on a compact interval [a, b] ⊂ ℝ, f and its analytic continuation f̅∞ satisfy the same properties that can be expressed in the language of real closed ordered fields. If f is not analytic, then this equivalence does not hold. These results suggest an analogy with the internal and external functions of nonstandard analysis: while the canonical continuations of analytic functions resemble internal functions, the continuations of non-analytic functions behave like external functions. Inspired by this analogy, we suggest some directions for further research. [ABSTRACT FROM AUTHOR]

Uncertainty quantification for geomechanical and reservoir predictions is in general a computationally intensive problem, especially if a direct Monte Carlo approach with large numbers of full-physics simulations is used. A common solution to this problem, well-known for the fluid flow simulations, is the adoption of surrogate modeling approximating the physical behavior with respect to variations in uncertain parameters. The objective of this work is the quantification of such uncertainty both within geomechanical predictions and fluid-flow predictions using a specific surrogate modeling technique, which is based on a functional approach. The methodology realizes an approximation of full-physics simulated outputs that are varying in time and space when uncertainty parameters are changed, particularly important for the prediction of uncertainty in vertical displacement resulting from geomechanical modeling. The developed methodology has been applied both to a subsidence uncertainty quantification example and to a real reservoir forecast risk assessment. The surrogate quality obtained with these applications confirms that the proposed method makes it possible to perform reliable time-space varying dependent risk assessment with a low computational cost, provided the uncertainty space is low-dimensional. [ABSTRACT FROM AUTHOR]

Theoretical and empirical studies of firm-industry dynamics have extensively focused on the process of growth. Theory predicts innovation, efficiency, profitability and financial status as the central channels through which firms can possibly achieve outstanding growth performance. The question is whether such high-growth performance is sustained over time and, if so, what are the factors enabling persistent high-growth patterns. Exploiting panels of Italian, Spanish, French and UK firms, we relate high growth, persistent high growth and other growth patterns to measures of efficiency, innovativeness, profitability and financial conditions. We find that high-growth firms are characterized by higher productivity and leverage, and that persistent high-growth firms do not systematically differ from other high-growth firms in none of the considered economic and financial dimensions. The findings are robust across countries, manufacturing and services. [ABSTRACT FROM AUTHOR]

In 2001, Renaud obtained a Grüss type operator inequality involving the usual trace functional. In this article, we give a refinement of that result, and we answer positively Renaud's open problem. [ABSTRACT FROM AUTHOR]

The upper tail of the firm size distribution is often assumed to follow a Power Law. Several recent papers, using different estimators and different data sets, conclude that the Zipf Law, in particular, provides a good fit, implying that the fraction of firms with size above a given value is inversely proportional to the value itself. In this article we compare the asymptotic and small sample properties of different methods through which this conclusion has been reached. We find that the family of estimators most widely adopted, based on an OLS regression, is in fact unreliable and basically useless for appropriate inference. This finding raises doubts about previously identified Zipf behavior. Based on extensive numerical analysis, we recommend the adoption of the Hill estimator over any other method when individual observations are available. [ABSTRACT FROM AUTHOR]