What happens when the stock markets are closed?

The normality of the log-return of stock prices is often assumed by the market players in order to use some useful results, as for instance, the Black-Scholes formula for pricing European options. However, several studies regarding different indexes have shown that the normality assumption of the returns usually fails. In this paper we analyse the normality assumption for intra-day and inter-day log-returns, comparing opening prices and/or closing prices for a large number of companies quoted in the Nasdaq Composite index. We use the Pearson's Chi-Square, Kolmogorov-Smirnov, Anderson-Darling, Shapiro-Wilks and Jarque-Bera goodness-of-fit tests to study the normality assumption.We find that the failure rate in the normality assumption for the log-return of stock prices is not the same for intra-day and inter-day prices, is somewhat test dependent and strongly dependent on some extreme price observations. To the best of our knowledge, this is the first study on the normality assumption for the log-return of stock prices dealing simultaneously with a large number of companies and normality tests, and at the same time considering various scenarios of intra-day, inter-day prices and data trimming

Does it change during recessions?

Funding Information: Margarida Catalão‐Lopes and Inês Carrilho‐Nunes gratefully acknowledge financial support from Fundação para a Ciência e a Tecnologia (FCT) under the project 2022.08870.PTDC and through UIDB/00097/2020. Joaquim P. Pina gratefully acknowledges financial support from FCT under the project LA/P/0069/2020 granted to the Associate Laboratory ARNET, and the strategic project UIDB/04292/2020 granted to MARE—Marine and Environmental Sciences Centre. Publisher Copyright: © 2023 The Authors. Business Strategy and The Environment published by ERP Environment and John Wiley & Sons Ltd.This paper assesses how environmental, social, and governance (ESG) news influence Portuguese stock market volatility depending on the business cycle. Given the lack of an adequate index to capture the effects of ESG media on the Portuguese stock market, a News Sentiment Index is developed. This index, which captures positive and negative ESG news on companies listed in the Portuguese Stock Index (PSI-20), is then used as an external regressor in symmetric and asymmetric GARCH-type models employed to model the stock market volatility. Results show that during non-crisis periods ESG news reduce returns' volatility, and that when considering the period preceding the financial crisis the disclosure content (positive or negative) of the news matter. However, during economic downturns, neither the amount nor the content disclosure of ESG news affect volatility; thus, ESG preoccupations might no longer be paramount.publishersversionepub_ahead_of_prin

Cartilage and bone regeneration: how close are we to bedside?

The treatment/regeneration of bone and cartilage diseases or defects, whether induced by rheumatism, joint dysplasia, trauma, or surgery presents great challenges that have not been fully solved by the current therapies. In the last few years, tissue engineering and regenerative medicine have been proposing advanced tools and technologies for bone and cartilage tissue regeneration, and some of which have successfully reached the market. Beyond the source of cells, the creation of superior structures for replacing defective bone and cartilage requires strong research in biomechanical signaling and synthesis of advanced biomaterials to mimic human tissues at the most varied levels. Natural and synthetic polymers, bioresorbable inorganic materials, and composites have been investigated for its potential as scaffolding materials with enhanced mechanical and biological properties. Porous scaffolds, hydrogels, and fibers are the most commonly biomimetic structures used for bone and cartilage tissue engineering. Herein, the concepts and current treatment strategies for bone and cartilage repair, as well as biomimetic strategies for bone and cartilage tissue engineering are overviewed. A global review of the ongoing clinical trials and of the scaffolds commercially available for the repair of osteochondral tissue is also presented.(undefined

Pretending to be Socially Responsible? The Role of Consumers’ Rewarding Behaviour

Extant evidence on corporate social responsibility (CSR) shows that consumers are willing to pay a premium if they infer that the firm is truly "prosocial" (i.e if it is altruistic), but their valuation of the product will not increase as much (and may even decrease) if they believe the company has an ulterior motive for CSR (i.e. if the firm is opportunistic). We pose that the CSR level of investment can be strategically used as a signalling tool to help consumers identify the true nature of the firm and solve this incomplete information problem. Using a signalling game, where altruistic firms want to express their nature and opportunistic ones want to conceal it, we explore the relative effectiveness of consumers’ premiums and penalties (expressed as demand increases or decreases, respectively) in the promotion of corporate truth-revealing behaviour. We also characterize the conditions for market equilibria in which altruistic firms are distinguished from opportunistic ones, allowing consumers to solve the information asymmetry and, with that, influence firms’ profits. Contrary to what might be expected, we show that rewards for altruistic CSR and penalties for opportunistic CSR are not symmetrically effective. Our results help companies to improve their CSR decisions, by understanding how consumers solve the information asymmetry regarding the true nature of the CSR investments. Especially for altruistic firms, this may be important to guarantee that CSR effort and expenses are not just a cost but turn into higher revenues and profits

Hierarchical HRP-crosslinked silk fibroin/ZnSr-doped TCP nancocomposites towards osteochondral tissue regeneration: Biomechanical performance and in vivo assessment

[Excerpt] Introduction. Recent investigations highlight promising regenerative strategies for osteochondral (OC) tissue treatment, such as hierarchical nanocomposite scaffolds containing ionic dopants.1,2 They allow cell infiltration and ECM formation throughout the engineered cartilage and subchondral tissues. The biomechanical behavior, antibacterial properties, and in vivo performance of hierarchical nanostructures combining enzymatically crosslinked silk fibroin (SF) and ZnSr-doped β-tricalcium phosphate (ZnSrTCP) for OC tissue regeneration is herein assessed. [...]Thanks to the Portuguese Foundation for Science and Technology for M-era-Net/0001/2014 project, and for the distinctions (IF/01285/2015) and (CEECIND/03673/2017)

Quantitative vs. Qualitative Criteria for Credit Risk Assessment

The existing vast literature on credit risk assessment and default prediction provides models building mostly in quantitative indicators. We present the results of a survey carried out of experts from the main banks in Portugal, conveying evidence on the dominant procedures undertaken by the Portuguese banking system. Our analysis concludes on the relevance of qualitative criteria, particularly management’s experience and reliability, and on their significant negative correlation with banks’ default records. Within this context the paper reflects on the role of multi-criteria decision analysis (MCDA) models as a way to process credit risk assessment integrating qualitative and quantitative aspects.banking; credit risk; qualitative criteria; multi-criteria decision analysis.

Tissue engineering scaffolds: Future perspectives

Tissue engineering (TE) and regenerative medicine combines the principles of biomaterials and cell transplantation to develop new tissues and to promote endogenous regeneration. The 3D scaffolds and matrices appeared as assertive approaches to guide the development of functional engineered tissues. Moreover, these structures, alone or in combination with cells and bioactive agents, bring the mechanical support during in vitro cell growthand in vivo implantation. A diversity of biomaterials and manufacturing methods, including 3D bioprinting, have been used to create novel alternatives to traditional TE strategies. Natural and synthetic polymers, bioceramics, or combination of these as composites have been used. These biomaterial choices oscillate from long-lasting implants to bioresorbable scaffolding structures, shown both with and without cells, growth factors and other bioactive agents. Herein, the approaches and emerging technologies applied for scaffolds and matrices processing, and the tissue-specific considerations for scaffolding TE purposes are highlighted and discussed. Focus is on what has been used and tested in animal models. Some of the most recent designs that allowed creating â multifunctionalâ structures with complex biological functions and their effectiveness for different TE applications are also outlined.project FROnTHERA (NORTE-01-0145-FEDER-000023), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). The financial support from the Portuguese Foundation for Science and Technology to Hierarchitech project (MERA-NET/0001/2014

Rapidly responsive silk fibroin hydrogels as an artificial matrix for the programmed tumor cells death

Timely and spatially-regulated injectable hydrogels, able to suppress growing tumors in response to conformational transitions of proteins, are of great interest in cancer research and treatment. Herein, we report rapidly responsive silk fibroin (SF) hydrogels formed by a horseradish peroxidase (HRP) crosslinking reaction at physiological conditions, and demonstrate their use as an artificial biomimetic three-dimensional (3D) matrix. The proposed SF hydrogels presented a viscoelastic nature of injectable hydrogels and spontaneous conformational changes from random coil to β-sheet conformation under physiological conditions. A human neuronal glioblastoma (U251) cell line was used for screening cell encapsulation and in vitro evaluation within the SF hydrogels. The transparent random coil SF hydrogels promoted cell viability and proliferation up to 10 days of culturing, while the crystalline SF hydrogels converted into β-sheet structure induced the formation of TUNEL-positive apoptotic cells. Therefore, this work provides a powerful tool for the investigation of the microenvironment on the programed tumor cells death, by using rapidly responsive SF hydrogels as 3D in vitro tumor models.publishedVersionPeer reviewe