A second look at the colors of the dinosaurs

In earlier work, I predicted that we would probably not be able to determine the colors of the dinosaurs. I lost this epistemic bet against science in dramatic fashion when scientists discovered that it is possible to draw inferences about dinosaur coloration based on the microstructure of fossil feathers (Vinther et al., 2008). This paper is an exercise in philosophical error analysis. I examine this episode with two questions in mind. First, does this case lend any support to epistemic optimism about historical science? Second, under what conditions is it rational to make predictions about what questions scientists will or will not be able answer? In reply to the first question, I argue that the recent work on the colors of the dinosaurs matters less to the debate about the epistemology of historical science than it might seem. In reply to the second question, I argue that it is difficult to specify a policy that would rule out the failed bet without also being too conservative.     

A new look at Heron's “Steam Engine”

Communicated by C. A. Wilson     

Multiple time-series modelling: Another look at the canadian money and income data

The practice of modelling the components of a vector time series to arrive at a joint model for the vector is considered. It is shown that in some cases this is not unreasonable. A vector ARMA model is used to model the Canadian money and income data. We also use these data to discuss the issue of differencing a multiple time series. Finally, models based on first and second differences are compared using forecasts.     

Evaluating forecasts: a look at aggregate bias and accuracy measures

In this paper an investigation is made of the properties and use of two aggregate measures of forecast bias and accuracy. These are metrics used in business to calculate aggregate forecasting performance for a family (group) of products. We find that the aggregate measures are not particularly informative if some of the one‐step‐ahead forecasts are biased. This is likely to be the case in practice if frequently employed forecasting methods are used to generate a large number of individual forecasts. In the paper, examples are constructed to illustrate some potential problems in the use of the metrics. We propose a simple graphical display of forecast bias and accuracy to supplement the information yielded by the accuracy measures. This support includes relevant boxplots of measures of individual forecasting success. This tool is simple but helpful as the graphic display has the potential to indicate forecast deterioration that can be masked by one or both of the aggregate metrics. The procedures are illustrated with data representing sales of food items. Copyright © 2005 John Wiley & Sons, Ltd.     

A new look at E.G. Björling and the Cauchy sum theorem

We give a new account of Björling’s contribution to uniform convergence in connection with Cauchy’s theorem on the continuity of an infinite series. Moreover, we give a complete translation from Swedish into English of Björling’s 1846 proof of the theorem. Our intention is also to discuss Björling’s convergence conditions in view of Grattan-Guinness’ distinction between history and heritage. In connection to Björling’s convergence theory we discuss the interpretation of Cauchy’s infinitesimals.     

A detailed look at crude oil price volatility prediction using macroeconomic variables

We investigate whether crude oil price volatility is predictable by conditioning on macroeconomic variables. We consider a large number of predictors, take into account the possibility that relative predictive performance varies over the out-of-sample period, and shed light on the economic drivers of crude oil price volatility. Results using monthly data from 1983:M1 to 2018:M12 document that variables related to crude oil production, economic uncertainty and variables that either describe the current stance or provide information about the future state of the economy forecast crude oil price volatility at the population level 1 month ahead. On the other hand, evidence of finite-sample predictability is very weak. A detailed examination of our out-of-sample results using the fluctuation test suggests that this is because relative predictive performance changes drastically over the out-of-sample period. The predictive power associated with the more successful macroeconomic variables concentrates around the Great Recession until 2015. They also generate the strongest signal of a decrease in the price of crude oil towards the end of 2008.     

Molecular mimicry: a critical look at exemplary instances in human diseases

Molecular mimicry, the concept that antigenic determinants of microorganisms resemble antigenic determinants of the host, is frequently cited as a plausible mechanism to account for the association of infection and autoimmune disease. Based on analogous sequences of amino acids or on cross-reactions of monoclonal antibodies, numerous examples of such mimicry have been reported. There are, however, no clear examples of a human disease caused by molecular mimicry.     

Enzymic formation of serotonin in mammalian blood platelets and red cells

Zusammenfassung Throbozyten aus Menschen- und Rinderblut enthalten eine hohe Aktivität an 5-Hydroxy-tryptophan-Decarboxylase und für diese enzymatische Reaktion scheint Pyridoxalphosphat als Cofaktor eine Rolle zu spielen.     

The centenary of W. C. Roentgen's discovery: A look at developments in science,clinical radiologic practice and environmental problems

The editors wish to thank Professor M. Elke for having coordinated this review.     

Neurexins and neuroligins: synapses look out of the nervous system

The scientific interest in the family of the so-called nervous vascular parallels has been growing steadily for the past 15 years, either by addition of new members to the group or, lately, by deepening the analysis of established concepts and mediators. Proteins governing both neurons and vascular cells are known to be involved in events such as cell fate determination and migration/guidance but not in the last and apparently most complex step of nervous system development, the formation and maturation of synapses. Hence, the recent addition to this family of the specific synaptic proteins, Neurexin and Neuroligin, is a double innovation. The two proteins, which were thought to be “simple” adhesive links between the pre- and post-synaptic sides of chemical synapses, are in fact extremely complex and modulate the most subtle synaptic activities. We will discuss the relevant data and the intriguing challenge of transferring synaptic activities to vascular functions.     

Vitamin C and gallstone formation: A preliminary report

Summary Gallstone formation in hypovitaminotic C guinea-pigs fed a high cholesterol diet was associated with qualitative changes in the gallbladder bile, namely, a high cholesterol concentration, a lowered bile acid content and diminished phospholipid-to-cholesterol and bile acid-to-cholesterol ratio.Acknowledgment. I am indebted to Prof. H. M. Sinclair (Oxford) and Drs K. M. L. Morris (City of London Polytechnic) and G. M. Murphy (Guys Hospital Medical School) for valuable discussion and advice, and to Mr J. A. Rawlings for technical assistance.     

Murine primitive neuroectodermal tumor: nucleolar isolation and RNA polymerase inhibition

Summary A nucleolar isolation procedure was developed for the murine primitive neuroectodermal tumor originally induced with methylcholanthrene. This procedure utilizes sonication for breakage of the nuclei at a magnesium concentration which disperses the extranucleolar chromatin. The nucleoli retain RNA synthetic activity which is inhibited to about 90% by actinomycin D and the chemotherapeutic drug adriamycin.Acknowledgments. This work was supported in part by USPHS Grant CM-67058. We wish to thank Dr William Brooks for his generous support of this project.     

Guaiacol-O-methyltransferase: A mammalian enzyme capable of forming di-O-methyl catecholamine derivatives

Résumé On a extrait et characterisé une enzyme capable de transférer aux catécholamines 4-O-méthyles le group méthyle provenant de l'S-adénosylméthionine et produire des substances diméthoxyques. Cette enzyme est active dans différents tissus de Mammifères.

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This work was supported by Public Health Service grants Nos. MH-08618 and MH-07961 and a Research Scientist's Award No. MH-14020, to A.J.F.     

Rates of ethiodide formation and the stereochemistry of ajmaline at C-21

Résumé Les auteurs ont mesuré les vitesses de réaction entre l'ajmaline plus dérivés et l'iodure d'éthyle. Les conclusions stéréochimiques deTaylor au C-21 en ont été confirmées.

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For previous papers on rates of quaternary iodide formation of alkaloids see (a)M. Shamma and J. B. Moss, J. Amer. chem. Soc.83, 5038 (1961) and (b)M. Shamma andE. F. Walker Jr., Chem. & Ind.1962, 1866.

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Acknowledgments. The authors wish to thank Dr.W. I. Taylor of CIBA Pharmaceutical Company for the generous gift of the compounds used in this study, and the National Institutes of Health (Grant No. GM-10608-01) for financial assistance.     

A method for karyotyping mouse blastocyst embryos developing from in vivo and in vitro fertilized eggs

A method for karyotyping blastocyst-staged mouse embryos is described. The use of this protocol results in the recovery of a high percentage (greater than 70%) of readable karyotypes and can be completed rapidly.