Forecast Combination for Euro Area Inflation: A Cure in Times of Crisis?

The period of extraordinary volatility in euro area headline inflation starting in 2007 raised the question whether forecast combination methods can be used to hedge against bad forecast performance of single models during such periods and provide more robust forecasts. We investigate this issue for forecasts from a range of short‐term forecasting models. Our analysis shows that there is considerable variation of the relative performance of the different models over time. To take that into account we suggest employing performance‐based forecast combination methods—in particular, one with more weight on the recent forecast performance. We compare such an approach with equal forecast combination that has been found to outperform more sophisticated forecast combination methods in the past, and investigate whether it can improve forecast accuracy over the single best model. The time‐varying weights assign weights to the economic interpretations of the forecast stemming from different models. We also include a number of benchmark models in our analysis. The combination methods are evaluated for HICP headline inflation and HICP excluding food and energy. We investigate how forecast accuracy of the combination methods differs between pre‐crisis times, the period after the global financial crisis and the full evaluation period, including the global financial crisis with its extraordinary volatility in inflation. Overall, we find that forecast combination helps hedge against bad forecast performance and that performance‐based weighting outperforms simple averaging. Copyright © 2017 John Wiley & Sons, Ltd.     

The role of the thioredoxin/thioredoxin reductase system in the metabolic syndrome: towards a possible prognostic marker?

Mammalian thioredoxin reductase (TrxR) is a selenoprotein with three existing isoenzymes (TrxR1, TrxR2, and TrxR3), which is found primarily intracellularly but also in extracellular fluids. The main substrate thioredoxin (Trx) is similarly found (as Trx1 and Trx2) in various intracellular compartments, in blood plasma, and is the cell’s major disulfide reductase. Thioredoxin reductase is necessary as a NADPH-dependent reducing agent in biochemical reactions involving Trx. Genetic and environmental factors like selenium status influence the activity of TrxR. Research shows that the Trx/TrxR system plays a significant role in the physiology of the adipose tissue, in carbohydrate metabolism, insulin production and sensitivity, blood pressure regulation, inflammation, chemotactic activity of macrophages, and atherogenesis. Based on recent research, it has been reported that the modulation of the Trx/TrxR system may be considered as a new target in the management of the metabolic syndrome, insulin resistance, and type 2 diabetes, as well as in the treatment of hypertension and atherosclerosis. In this review evidence about a possible role of this system as a marker of the metabolic syndrome is reported.     

H-Y antigen expression in heterogametic males (XY) and females (ZW): a factor in reproductive strategy?

Summary The cells of heterogametic females with ZW sex chromosomes express H-Y or H-W antigen. A hypothesis is formulated to explain why these animals are capable of practicingamphigonia retardata, i.e. delay in actual fertilization of eggs by retaining viable sperm within the oviduct for a considerable time (several months).     

The role of mammalian target of rapamycin (mTOR) in the regulation of pancreatic β-cell mass: implications in the development of type-2 diabetes

Type-2 diabetes mellitus (T2DM) is a disorder that is characterized by high blood glucose concentration in the context of insulin resistance and/or relative insulin deficiency. It causes metabolic changes that lead to the damage and functional impairment of organs and tissues resulting in increased morbidity and mortality. It is this form of diabetes whose prevalence is increasing at an alarming rate due to the 'obesity epidemic', as obesity is a key risk factor in the development of insulin resistance. However, the majority of individuals who have insulin resistance do not develop diabetes due to a compensatory increase in insulin secretion in response to an increase in insulin demand. This adaptive response is sustained by an increase in both β-cell function and mass. Importantly, there is increasing evidence that the Serine/Threonine kinase mammalian target of rapamycin (mTOR) plays a key role in the regulation of β-cell mass and therefore likely plays a critical role in β-cell adaptation. Therefore, the primary focus of this review is to summarize our current understanding of the role of mTOR in stimulating pancreatic β-cell mass and thus, in the prevention of type-2 diabetes.     

Elevated α-2-serum proteins as a possible genetic marker in spontaneous hereditary diabetes mellitus of the chinese hamster (cricetulus griseus)

Zusammenfassung Bei chinesischen Hamstern aus Inzuchten mit erblicher Zuckerkrankheit wurden erhöhte Serum--2-Eiweisswerte konstatiert. Die Erhöhung erfolgt vor Auftreten der Hyperglykämie oder Blutgefäss- und anderen sekundären pathologischen Veränderungen. Es wird gefolgert, dass die Eiweisserhöhung gen-bedingt ist und wahrscheinlich chemisch abnormales Eiweiss betrifft.

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This investigation was supported in part by research grants from the National Institutes of Health, USPHS #E1560 and #CY3335, the National Science Foundation (#6-9602), and the Damon Runyon Memorial Fund (#293).     

TNF-α upregulates adenosine 2b (A2b) receptor expression and signaling in intestinal epithelial cells: a basis for A2bR overexpression in colitis

Adenosine is an endogenous signaling molecule upregulated during inflammatory conditions. Acting through the A2b receptor (A2bR), the predominant adenosine receptor in human colonic epithelia, adenosine has been directly implicated in immune and inflammatory responses in the intestine. Little is known about expression and regulation of A2bR during inflammation. Tumor necrosis factor alpha (TNF-α) is highly upregulated during chronic and acute inflammatory diseases. This study examined the expression of A2bR during colitis and studied effects of TNF-α on A2bR expression, signaling and function. Results demonstrated that A2bR expression increases during active colitis. TNF-α pretreatment of intestinal epithelial cells increased A2bR messenger RNA and protein expression. TNF-α significantly increased adenosine-induced membrane recruitment of A2bR and cyclic adenosine monophosphate downstream signaling. Further, TNF-α potentiated adenosine-induced shortcircuit current and fibronectin secretion. In conclusion, we demonstrated that TNF-α is an important regulator of A2bR, and during inflammation, upregulation of TNF-α may potentiate adenosine-mediated responses. Received 21 July 2005; received after revision 22 August 2005; accepted 19 September 2005 †These authors contributed equally to this work.     

Insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs): post-transcriptional drivers of cancer progression?

The insulin-like growth factor-2 mRNA-binding proteins 1, 2, and 3 (IGF2BP1, IGF2BP2, IGF2BP3) belong to a conserved family of RNA-binding, oncofetal proteins. Several studies have shown that these proteins act in various important aspects of cell function, such as cell polarization, migration, morphology, metabolism, proliferation and differentiation. In this review, we discuss the IGF2BP family’s role in cancer biology and how this correlates with their proposed functions during embryogenesis. IGF2BPs are mainly expressed in the embryo, in contrast with comparatively lower or negotiable levels in adult tissues. IGF2BP1 and IGF2BP3 have been found to be re-expressed in several aggressive cancer types. Control of IGF2BPs’ expression is not well understood; however, let-7 microRNAs, β-catenin (CTNNB1) and MYC have been proposed to be involved in their regulation. In contrast to many other RNA-binding proteins, IGF2BPs are almost exclusively observed in the cytoplasm where they associate with target mRNAs in cytoplasmic ribonucleoprotein complexes (mRNPs). During development, IGF2BPs are required for proper nerve cell migration and morphological development, presumably involving the control of cytoskeletal remodeling and dynamics, respectively. Likewise, IGF2BPs modulate cell polarization, adhesion and migration in tumor-derived cells. Moreover, they are highly associated with cancer metastasis and the expression of oncogenic factors (KRAS, MYC and MDR1). However, a pro-metastatic role of IGF2BPs remains controversial due to the lack of ‘classical’ in vivo studies. Nonetheless, IGF2BPs could provide valuable targets in cancer treatment with many of their in vivo roles to be fully elucidated.     

C-terminal fragment (residues 61–91) ofβ-lipotropin: Is it the natural opiate-like neurohormon of the brain?

Summary The C-terminal fragment of porcine -lipotropin (residues 61–91) has a very strong analgesic activity in vivo in rats. It is 20 times more potent than morphine if administered intracerebroventricularly (ICV) to rats. Its effect could be antagonized by naloxone. Presumably it is a natural opiate-like neurohormon of the brain.     

Brokering Instruments in Napoleon's Europe: The Italian Journeys of Franz Xaver von Zach (1807–1814)

This paper explores the interactions between scientific travel, politics, instrument making and the epistemology of scientific instruments in Napoleon's Europe. In the early 1800s, the German astronomer Franz Xaver von Zach toured Italy and Southern France with instruments made by G. Reichenbach in his newly-established Bavarian workshop. I argue that von Zach acted as a broker for German technology and science and that travel, personal contacts and direct demonstrations were crucial in establishing Reichenbach's reputation and in conquering new markets. The rise of German instrument making highlights the complexity of the scientific relationship between the centre and the peripheries in Napoleon's empire, and reveals the existence of diverging views on the role of instruments and of their makers. In von Zach's view, Reichenbach's instruments could not penetrate the French market because Parisian astronomers focused on mathematical astronomy and, for both political and epistemological reasons, dismissed instruments and material innovations from the peripheries. The German astronomer and his Italian colleagues, on the contrary, regarded Reichenbach's technical achievements as outstanding contributions to astronomy, and considered the political and cultural hegemony of the capital as a hindrance to the advancement of science.     

A stepwise model of polyreactivity of the T cell antigen-receptor (TCR): its impact on the self–nonself discrimination and on related observations (receptor editing,anergy, dual receptor cells)

The existence of antigen-receptors, BCR, and T cell antigen-receptors, that are “polyreactive”, necessitates a rethinking of its effect on two problems faced by the “adaptive” immune system: the self (S)–nonself (NS) discrimination and the determination of effector class. Here, we will concentrate on the impact of polyreactivity on the S–NS discrimination. The anti-S cells interacting with S (i.e., responding to Signal 1) are on the pathway to inactivation. Before irreversibility sets in, these cells can be activated by a second signal (Signal 2) from an effector T-helper (eTh). As these polyreactive anti-S cells express anti-NS specificities, they can be activated by recognition of NS-epitopes in the host’s normal immunogenic load with the potential to result in autoimmunity. This problem is delineated using a discrete structural model, the corollaries of which are: (1) a two-step pathway for the purging of anti-S cells (i.e., the S–NS discrimination), and (2) defensible contexts within which to view the phenomena of receptor editing, anergy, and dual receptor cells.     

The publication strategies of Jöns Jacob Berzelius (1779–1848): negotiating national and linguistic boundaries in chemistry

SUMMARY

This article follows the publication strategies of the Swedish chemist Jöns Jacob Berzelius (1779–1848). It focuses on the role of language and translation in Berzelius' efforts to strengthen his own reputation, and that of Swedish science. As an author and editor, Berzelius encouraged the translation of his own works into several languages, while endeavouring to preserve the status of Swedish as a language of scientific publication in the face of French, and increasingly German and English, dominance. Reforming the Transactions of the Royal Swedish Academy of Sciences and launching several new scientific periodicals, Berzelius also attempted to influence the publication practices in other countries.

Recent scholarship on the history of scientific publication has drawn attention to the practical difficulties of determining and getting hold of the relevant publications in one's field, the ‘malleability’ of the journal medium, and the common practice of reprinting and summarising papers published elsewhere. Berzelius’ publication strategies highlight translation – time-consuming, unreliable and problematic in terms of authorisation and ownership – as one aspect of the wider problem of communicating across national and linguistic boundaries. Berzelius' struggles with the practicalities of communicating across borders in times of war, the choice of language and its consequences, and national standards of publication, demonstrate the importance of a transnational perspective on the history of scientific publication.     

Reading Gauss in the Computer Age: On the U.S. Reception of Gauss’s Number Theoretical Work (1938–1989)

C.F Gauss’s computational work in number theory attracted renewed interest in the twentieth century due to, on the one hand, the edition of Gauss’s Werke, and, on the other hand, the birth of the digital electronic computer. The involvement of the U.S. American mathematicians Derrick Henry Lehmer and Daniel Shanks with Gauss’s work is analysed, especially their continuation of work on topics as arccotangents, factors of n ² + a ², composition of binary quadratic forms. In general, this strand in Gauss’s reception is part of a more general phenomenon, i.e. the influence of the computer on mathematics and one of its effects, the reappraisal of mathematical exploration. I would like to thank the Alexander-von-Humboldt-Stiftung for funding this research. For their comments I would like to thank Catherine Goldstein, Norbert Schappacher and especially John Brillhart.     

‘… not fundamental in a state of full civilization’: The Sociedad Astronómica de Barcelona (1910–1921) and its Popularization Programme

Scrutinizing the main activities of the Sociedad Astronómica de Barcelona (SAB), a scientific society that was founded in 1910 and lasted until 1921, this paper analyses how and why its members disseminated astronomy to society at large. Inspired by Camille Flammarion (1842–1925), and with a strong amateur character, the programme of the SAB raised interest among academic scientists, politicians, priests, navy officers, educated audiences, and positivist anticlerical writers. It rapidly conquered the public sphere through well-attended lectures, exhibitions, observations, and publications. In the context of an industrial city, which at that time was suffering serious social tensions, the popularization of astronomy transcended social and cultural boundaries. It created common ground between expert and lay knowledge, science and art, the ‘natural’ and the ‘social’, and between science and religion. In addition, it was considered as one of the only possible ways to raise the scientific level of a country such as Spain, which at that time perceived itself as peripheral, even backward, in terms of mainstream innovations in science and technology.