Publication Bias in Asset Pricing Research

Researchers are more likely to share notable findings. As a result, published findings tend to overstate the magnitude of real-world phenomena. This bias is a natural concern for asset pricing research, which has found hundreds of return predictors and little consensus on their origins. Empirical evidence on publication bias comes from large scale meta-studies. Meta-studies of cross-sectional return predictability have settled on four stylized facts that demonstrate publication bias is not a dominant factor: (1) almost all findings can be replicated, (2) predictability persists out-of-sample, (3) empirical $t$-statistics are much larger than 2.0, and (4) predictors are weakly correlated. Each of these facts has been demonstrated in at least three meta-studies. Empirical Bayes statistics turn these facts into publication bias corrections. Estimates from three meta-studies find that the average correction (shrinkage) accounts for only 10 to 15 percent of in-sample mean returns and that the risk of inference going in the wrong direction (the false discovery rate) is less than 6%. Meta-studies also find that t-statistic hurdles exceed 3.0 in multiple testing algorithms and that returns are 30 to 50 percent weaker in alternative portfolio tests. These facts are easily misinterpreted as evidence of publication bias effects. We clarify these misinterpretations and others, including the conflating of ``mostly false findings'' with ``many insignificant findings.'' Cross-sectional predictability may not be representative of other fields. Meta-studies of real-time equity premium prediction suggest a much larger effect of publication bias, though publication bias in this and other areas of asset pricing is an important area for future research

Conservation of pregnancy-specific glycoprotein (PSG) N domains following independent expansions of the gene families in rodents and primates

BACKGROUND: Rodent and primate pregnancy-specific glycoprotein (PSG) gene families have expanded independently from a common ancestor and are expressed virtually exclusively in placental trophoblasts. However, within each species, it is unknown whether multiple paralogs have been selected for diversification of function, or for increased dosage of monofunctional PSG. We analysed the evolution of the mouse PSG sequences, and compared them to rat, human and baboon PSGs to attempt to understand the evolution of this complex gene family. RESULTS: Phylogenetic tree analyses indicate that the primate N domains and the rodent N1 domains exhibit a higher degree of conservation than that observed in a comparison of the mouse N1 and N2 domains, or mouse N1 and N3 domains. Compared to human and baboon PSG N domain exons, mouse and rat PSG N domain exons have undergone less sequence homogenisation. The high non-synonymous substitution rates observed in the CFG face of the mouse N1 domain, within a context of overall conservation, suggests divergence of function of mouse PSGs. The rat PSG family appears to have undergone less expansion than the mouse, exhibits lower divergence rates and increased sequence homogenisation in the CFG face of the N1 domain. In contrast to most primate PSG N domains, rodent PSG N1 domains do not contain an RGD tri-peptide motif, but do contain RGD-like sequences, which are not conserved in rodent N2 and N3 domains. CONCLUSION: Relative conservation of primate N domains and rodent N1 domains suggests that, despite independent gene family expansions and structural diversification, mouse and human PSGs retain conserved functions. Human PSG gene family expansion and homogenisation suggests that evolution occurred in a concerted manner that maintains similar functions of PSGs, whilst increasing gene dosage of the family as a whole. In the mouse, gene family expansion, coupled with local diversification of the CFG face, suggests selection both for increased gene dosage and diversification of function. Partial conservation of RGD and RGD-like tri-peptides in primate and rodent N and N1 domains, respectively, supports a role for these motifs in PSG function

Do European quality assurance frameworks support integration of transformative learning for sustainable development in higher education?

Purpose A transition toward sustainable development requires engagement of university students in transformative learning. Therefore, quality frameworks and processes should support deep approaches to sustainable development in higher education. Research and initiatives that connect sustainable development, higher education and quality assurance (QA) are lacking. This study aims to explore to what extent quality assurance agencies in Europe support transformative learning for sustainable development in their frameworks. Design/methodology/approach The authors conducted a qualitative analysis of national QA frameworks in the European Higher Education Area (EHEA) to assess whether they support transformative learning for sustainable development. First, frequency analysis was undertaken; second, a blended coding approach was used to investigate whether and how transformative learning for sustainable development is addressed. Findings Overall, the authors found little support for transformative learning for sustainable development in most QA frameworks. One exception is the framework of the United Kingdom, which includes a specific guide on education for sustainable development wherein transformative learning is prominently mentioned. To a lesser extent, some support exists in the frameworks of Estonia, Holy See, Romania, Sweden, Switzerland and Ukraine. Although the transformative learning for sustainable development approach is not explicitly mentioned in most QA frameworks, many of them contain opportunities to highlight it. France and The Netherlands offer guidelines and criteria for acquiring a sustainable development label, while Andorra suggests including the sustainable development goals in institutional quality assessment. Originality/value The research provides the first map of how countries within the EHEA support transformative learning for sustainable development in national QA systems

Convergent evolution of pregnancy-specific glycoproteins in human and horse

Pregnancy-specific glycoproteins (PSGs) are members of the carcinoembryonic antigen cell adhesion molecule (CEACAM) family that are secreted by trophoblast cells. PSGs may modulate immune, angiogenic and platelet responses during pregnancy. Until now, PSGs are only found in species that have a highly invasive (hemochorial) placentation including humans, mice and rats. Surprisingly, analyzing the CEACAM gene family of the horse, which has a non-invasive epitheliochorial placenta, with the exception of the transient endometrial cups, we identified equine CEACAM family members that seem to be related to PSGs of rodents and primates. We identified seven genes that encode secreted PSG-like CEACAMs. Phylogenetic analyses indicate that they evolved independently from an equine CEACAM1-like ancestor rather than from a common PSG-like ancestor with rodents and primates. Significantly, expression of PSG-like genes (CEACAM44, CEACAM48, CEACAM49 and CEACAM55) was found in non-invasive as well as invasive trophoblast cells such as purified chorionic girdle cells and endometrial cup cells. Chorionic girdle cells are highly invasive trophoblast cells that invade the endometrium of the mare where they form endometrial cups and are in close contact with maternal immune cells. Therefore, the microenvironment of invasive equine trophoblast cells has striking similarities to the microenvironment of trophoblast cells in hemochorial placentas, suggesting that equine PSG-like CEACAMs and rodent and primate PSGs have undergone convergent evolution. This is supported by our finding that equine PSG-like CEACAM49 exhibits similar activity to certain rodent and human PSGs in a functional assay of platelet–fibrinogen binding. Our results have implications for understanding the evolution of PSGs and their functions in maternal–fetal interactions

An Inquiry into Model Validity When Addressing Complex Sustainability Challenges

Scientific modelling is a prime means to generate understanding and provide much-needed information to support public decision-making in the fluid area of sustainability. A growing, diverse sustainability modelling literature, however, does not readily lend itself to standard validation procedures, which are typically rooted in the positivist principles of empirical verification and predictive success. Yet, to be useful to decision-makers, models, including their outputs and the processes through which they are established must be, and must be seen to be “valid.” *is study explores what model validity means in a problem space with increasingly interlinked and fast-moving challenges. We examine validation perspectives through ontological, epistemic, and methodological lenses, for a range of modelling approaches that can be considered as “complexity-compatible.” *e worldview taken in complexity-compatible modelling departs from the more standard modelling assumptions of complete objectivity and full predictability. Drawing on different insights from complexity science, systems thinking, economics, and mathematics, we suggest a ten-dimensional framework for progressing on model validity when investigating sustainability concerns. As such, we develop a widened view of the meaning of model validity for sustainability. It includes (i) acknowledging that several facets of validation are critical for the successful modelling of the sustainability of complex systems; (ii) tackling the thorny issues of uncertainty, subjectivity, and unpredictability; (iii) exploring the realism of model assumptions and mechanisms; (iv) embracing the role of stakeholder engagement and scrutiny throughout the modelling process; and (v) considering model purpose when assessing model validity. We wish to widen the debate on the meaning of model validity in a constructive way. We conclude that consideration of all these elements is necessary to enable sustainability models to support, more effectively, decision-making for complex interdependent systems

In-Flight Reconfiguration with System-On-Module Based Architectures for Science Instruments on Nanosatellites

For science payloads on nanosatellite missions, there is a great interest in cost-effective, reliable and state-of-the-art computing performance. Highly integrated system architectures combine reconfigurable System-on-Chip (SoC) devices, memory and peripheral interfaces in a single System-on-Module (SoM) and offer low resource requirements regarding power and mass, but moderate to high processing power capabilities. The major advantages of these architectures are flexibility, (re)programmability, modularity and module reuse. However, it is a challenge to use SoM with COTS based memories devices in a radiation sensitive environment. In order to achieve these requirements, mitigation measures, such as the use of redundant or alternative memory devices and in-flight reconfiguration, are important in terms of reliability. Reprogramming strategies e.g. partial dynamic reconfiguration and scrubbing techniques are published in the past. With a remote sensing instrument for atmospheric temperature measurements using a SRAM-based Xilinx Zynq-7000 SoM, we combine some of these techniques with supervisor circuits to select the boot image from alternative memory devices. The approach distinguishes between programmable logic and processing system reconfiguration, and enables in-flight firmware updates in the case of Single Event Effect (SEE) hazards or changing measurement conditions

Breves apontamentos sobre a construção epistemológica do sistema jurídicointernacional em Hans Kelsen

O presente artigo pretende demonstrar as implicações da teoria de Hans Kelsen no sistema jurídico-internacional, sobretudo nas questões relativas à criação e à aplicação do Direito Internacional Público. Nesse contexto, trabalham-se as questões das fontes, das lacunas, dos costumes, dos tratados de Direito Internacional Público e das decisões dos organismos internacionais. Após, com base nos princípios kelsenianos de Direito Internacional Público, utiliza-se o Direito como meio de resolução das controvérsias por meio dos acordos internacionais e por meio dos Tribunais internacionais. Ao final, demonstram-se as principais implicações epistemológicas da teoria kelseniana na construção do estatuto jurídico-internacional

An Inquiry into Model Validity When Addressing Complex Sustainability Challenges

Scientific modelling is a prime means to generate understanding and provide much-needed information to support public decision-making in the fluid area of sustainability. A growing, diverse sustainability modelling literature, however, does not readily lend itself to standard validation procedures, which are typically rooted in the positivist principles of empirical verification and predictive success. Yet, to be useful to decision-makers, models, including their outputs and the processes through which they are established must be, and must be seen to be “valid.” This study explores what model validity means in a problem space with increasingly interlinked and fast-moving challenges. We examine validation perspectives through ontological, epistemic, and methodological lenses, for a range of modelling approaches that can be considered as “complexity-compatible.” The worldview taken in complexity-compatible modelling departs from the more standard modelling assumptions of complete objectivity and full predictability. Drawing on different insights from complexity science, systems thinking, economics, and mathematics, we suggest a ten-dimensional framework for progressing on model validity when investigating sustainability concerns. As such, we develop a widened view of the meaning of model validity for sustainability. It includes (i) acknowledging that several facets of validation are critical for the successful modelling of the sustainability of complex systems; (ii) tackling the thorny issues of uncertainty, subjectivity, and unpredictability; (iii) exploring the realism of model assumptions and mechanisms; (iv) embracing the role of stakeholder engagement and scrutiny throughout the modelling process; and (v) considering model purpose when assessing model validity. We wish to widen the debate on the meaning of model validity in a constructive way. We conclude that consideration of all these elements is necessary to enable sustainability models to support, more effectively, decision-making for complex interdependent systems