Osmotic behaviour of isolated axons of a euryhaline and a stenohaline crustacean

Résumé Les axones isolés du crustacé euryhalinEriocheir sinensis sont capables d'effectuer une régularisation de volume lorsqu'ils sont soumis à des chocs hypo-osmotiques. Les mécanismes pouvant être impliqués dans ce processus sont discutés.

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Chercheur qualifié du Fonds National de la Recherche Scientifique.     

Fine structure of a neurosecretory axon in a crustacean skeletal muscle

Résumé Un axone neuro-sécréteur à extrémités localisées dans le muscle squelettique du craneCarcinus est décrit. Ces extrémités contiennent 6 sortes de vésicules ayant les diamètres de 1300 a 3700 . Il est suggéré que es petites vésicules correspondent à la phase de rétablisement de la membrane, pendant la décharge des granules euro-sécréteurs. On suppose aussi que cet axone peutêtre l'intermédiaire d'une influence trophique du nerf sur le muscle.

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I am most grateful to Mr.K. Oates and Mr.G. R. Abram for excellent technical assistance.

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Supported by a Research Studentship from the Science Research Council.     

Nucleic acid content of a diploid and of a triploid strain ofDrosophila melanogaster

Zusammenfassung Beim triploidenDrosophila-StammFM4, y ^31d sc ⁸ dm B/y ² sc w ^a ec.=ist der DNS-Anteil an der fettfreien Trockenmasse wesentlich höher als beim diploiden Stamm «Berlin normal ». Der RNS-Anteil an der fettfreien Trockenmasse stimmt in beiden Stämmen überein. Es wird diskutiert, dass die 2 Genome der diploidenDrosophila offensichtlich etwa ebenso aktiv sind wie die 3 Genome der triploiden.Drosophila verfügt also offenbar über einen Regulationsmechanismus, der die RNS-Konzentration trotz unterschiedlichen DNS-Gehalts konstant hält.     

Isolation of a cytochrome of the antimycin a sensitive pathway for DPNH oxidation

Zusammenfassung Ein neues Cytochrom ist aus Schweineleber isoliert worden. Es wird durch DPNH-Cytochrom-c-Reduktase reduziert. Antimycin A hemmt diese Reaktion, die nur in Gegenwart des Slater-Faktors abläuft.Es ist wahrscheinlich, dass dieses Cytochrom in die Elektronentransportreihe, und zwar zwischen Reduktase und Cytochrom c, eingeschaltet ist.     

Co-existence of a guanidine-dependence and of a thiopyrimidine dependence in the same strain of poliovirus

Riassunto Una doppia dipendenza nei confronti della guanidina e di una tiopirimidina (S-7) può essere indotta in uno stesso stipite di poliovirus 1.     

Immunotherapy against antigenic tumors: a game with a lot of players

Our understanding of how immune responses are generated and regulated drives the design of possible immunotherapies for cancer patients. For that reason, we first describe briefly the actual immunological theories and their common perspectives about cancer vaccine development. Second, we describe cancer vaccines that are able to induce tumor-specific immune responses in cancer patients. However, these responses are not always followed by tumor rejection. At the end of the review, we discuss two possible reasons that might explain this dichotomy of cancer immunology. First, the immune response generated, although detectable, may not be quantitatively sufficient to reject the tumor. Second, the tumor microenvironment may modulate tumor cell susceptibility to the systemic immune response induced by the immunization. Finally, we discuss what, in our opinion, might be the best way to improve cancer vaccine strategies and how the relationship between the tumor and its surroundings might be studied in more details. Received 21 June 2001; received after revision 15 August 2001; accepted 15 August 2001     

Signal extraction and estimation of a trend: a Monte Carlo study

Several authors (King and Rebelo, 1993; Cogley and Nason, 1995) have questioned the use of exponentially weighted moving average filters such as the Hodrick–Prescott filter in decomposing a series into a trend and cycle, claiming that they lead to the observation of spurious or induced cycles and to misinterpretation of stylized facts. However, little has been done to propose different methods of estimation or other ways of defining trend extraction. This paper has two main contributions. First, we suggest that the decomposition between the trend and cycle has not been done in an appropriate way. Second, we argue for a general to specific approach based on a more general filter, the stochastic trend model, that allows us to estimate all the parameters of the model rather than fixing them arbitrarily, as is done with mainly of the commonly used filters. We illustrate the properties of the proposed technique relative to the conventional ones by employing a Monte Carlo study. Copyright © 1999 John Wiley & Sons, Ltd.     

Decrease of K+ conductance underlying a depolarizing photoresponse of a molluscan extraocular photoreceptor

Summary An identified neurone in theOnchidium abdominal ganglion responds to light with a depolarizing generator potential, so that this neurone functions as an extraocular photoreceptor. The light-evoked depolarizing response is produced by a selective decrease in K⁺ conductance.     

Towards a taxonomy of forecast error measures a factor-comparative investigation of forecast error dimensions

This study explores the nature of information conveyed by 14 error measures drawn from the literature, using real-life forecasting data from 691 individual product items over six quarterly periods. Principal components analysis is used to derive factor solutions that are subsequently compared for two forecasting methods, a version of Holt's exponential smoothing, and the random walk model (Naive 1). The results reveal four underlying forecast error dimensions that are stable across the two factor solutions. The potentially confounding influence of sales volume on the derived error dimensions is also explored via correlation analysis.