The ecological rationality of explanatory reasoning

There is growing evidence that explanatory considerations influence how people change their degrees of belief in light of new information. Recent studies indicate that this influence is systematic and may result from people’s following a probabilistic update rule. While formally very similar to Bayes’ rule, the rule or rules people appear to follow are different from, and inconsistent with, that better-known update rule. This raises the question of the normative status of those updating procedures. Is the role explanation plays in people’s updating their degrees of belief a bias? Or are people right to update on the basis of explanatory considerations, in that this offers benefits that could not be had otherwise? Various philosophers have argued that any reasoning at deviance with Bayesian principles is to be rejected, and so explanatory reasoning, insofar as it deviates from Bayes’ rule, can only be fallacious. We challenge this claim by showing how the kind of explanation-based update rules to which people seem to adhere make it easier to strike the best balance between being fast learners and being accurate learners. Borrowing from the literature on ecological rationality, we argue that what counts as the best balance is intrinsically context-sensitive, and that a main advantage of explanatory update rules is that, unlike Bayes’ rule, they have an adjustable parameter which can be fine-tuned per context. The main methodology to be used is agent-based optimization, which also allows us to take an evolutionary perspective on explanatory reasoning.     

The IQGAP-related protein DGAP1 mediates signaling to the actin cytoskeleton as an effector and a sequestrator of Rac1 GTPases

Proteins are typically categorized into protein families based on their domain organization. Yet, evolutionarily unrelated proteins can also be grouped together according to their common functional roles. Sequestering proteins constitute one such functional class, acting as macromolecular buffers and serving as an intracellular reservoir ready to release large quantities of bound proteins or other molecules upon appropriate stimulation. Another functional protein class comprises effector proteins, which constitute essential components of many intracellular signal transduction pathways. For instance, effectors of small GTP-hydrolases are activated upon binding a GTP-bound GTPase and thereupon participate in downstream interactions. Here we describe a member of the IQGAP family of scaffolding proteins, DGAP1 from Dictyostelium, which unifies the roles of an effector and a sequestrator in regard to the small GTPase Rac1. Unlike classical effectors, which bind their activators transiently leading to short-lived signaling complexes, interaction between DGAP1 and Rac1-GTP is stable and induces formation of a complex with actin-bundling proteins cortexillins at the back end of the cell. An oppositely localized Rac1 effector, the Scar/WAVE complex, promotes actin polymerization at the cell front. Competition between DGAP1 and Scar/WAVE for the common activator Rac1-GTP might provide the basis for the oscillatory re-polarization typically seen in randomly migrating Dictyostelium cells. We discuss the consequences of the dual roles exerted by DGAP1 and Rac1 in the regulation of cell motility and polarity, and propose that similar signaling mechanisms may be of general importance in regulating spatiotemporal dynamics of the actin cytoskeleton by small GTPases.     

Project Management Supports (Requisitely) Holistic: Socially Responsible Action in Business Systems

This article emphasizes the role of projects and project management in assuring socially responsible acting of contemporary business systems, presenting some practical applications in the field of tourism. With arising number of projects in business systems and their growing strategic importance, the role of project management has radically been changing for the last two decades. Managing organizations, as a central topic among seven crucial topics in ISO 26000 on social responsibility, is strongly associated with managing projects. Projects have important influence on the established as well as on establishing ongoing operations and are important tools in assuring business systems’ strategic development, by exposing interdependences and supporting the requisitely holistic approach. This article tries to fill the gap we detected in literature on social responsibility where projects and project management seem not to have a proper role. Four different links and interdependencies between project management and systems theory (which ISO 26000 reinforces) are exposed: (1) systemic treatment of project management, (2) systematical treatment of projects as holistic works, (3) systemic treatment of projects as parts of BSs’ strategies, (4) systemic treatment of projects throughout their entire life cycle.     

The effect of D-6-methyl-8-[β-isopropylaminoethyl] ergoline-I on the lactation in nursing rats

D-6-Methyl-8-[-isopropylaminoethyl] ergoline-I [VÚFB-10726], beginning from the dose of 0.05 mg/kg p.o., suppresses lactation through the inhibition of prolactin secretion in nursing rats.     

Target organs of131I-chorionic gonadotrophine in immature female rat

Zusammenfassung Die Einlagerung von¹³¹I-HCG und¹³¹I-Serumalbumin in einige Organe unreifer Rattenweibchen wurde gammaradiometrisch gemessen. Eine signifikant erhöhte Akkumulation der Radioaktivität nach¹³¹I-HCG-Verabreichung wurde im Ovarium, dem Uterus, der Hypophyse und der Schilddrüse festgestellt.     

Fibrinolytic proteases in snake venoms

Zusammenfassung Fibrinolysine zweier Schlangengifte haben — im Gegensatz zu Plasmin und Trypsin — keinen Plasminogen-aktivierenden Effekt, noch sind sie durch Proteasen-Inhibitoren gehemmt. Sowohl in vivo wie auch in vitro sind sie durch Plasmaproteine inaktiviert, was jedoch nicht auf ₁ und ₂-Antiplasmine zurückzuführen ist. Die Spaltprodukte der Toxin-Fibrinogenolyse besitzen einen hohen Gehalt an Antithrombin VI.     

The effect of early weaning on spermiogenesis in adult rats

Zusammenfassung Junge, vorzeitig (18 Tage nach der Geburt entwöhnte Ratten) zeigen im Alter von 12 Monaten Schädigungen im spermiogenen Hodenepithel. 12 Tage später entwöhnte Ratten entwickeln sich normal. Die beobachteten Schädigungen treten im Alter von 6 Monaten noch nicht auf.     

Potentiation of the cancerostatic effect of 6-azauridine and 6-azacytidine with 5-bis-(2-chloroethyl)aminomethyluracil

Zusammenfassung Es wird gezeigt, dass die cancerostatische Wirkung von 6-Azauracil und 6-Azacytidin bei Mäusen durch 5-Bis-(2-chloroethyl)aminomethyluracil signifikant potenziert wird.     

Inhibitory interaction between spinal reflexes to primary afferents

Zusammenfassung Die Depolarisation der Ia Nervenfasern, welche durch eine Entladung in Ia Fasern eines Flexormuskelnerven reflektorisch ausgelöst werden kann, wird durch Reizung der sensorisch-motorischen Grosshirnrinde oder der Flexor-Reflex-Afferenten gehemmt.Es wird vorausgesetzt, dass der Mechanismus dieser Hemmung präsynaptisch ist, und zwar durch eine Depolarisation der Endigungen der Interneuronen, welche die Wirkung von Ia- zu Ia-Afferenten übertragen.