Re-orienting discussions of scientific explanation: A functional perspective

Philosophy of science offers a rich lineage of analysis concerning the nature of scientific explanation, but the vast majority of this work, aiming to provide an analysis of the relation that binds a given explanans to its corresponding explanandum, presumes the proper analytic focus rests at the level of individual explanations. There are, however, other questions we could ask about explanation in science, such as: What role(s) does explanatory practice play in science? Shifting focus away from explanations, as achievements, toward explaining, as a coordinated activity of communities, the functional perspective aims to reveal how the practice of explanatory discourse functions within scientific communities given their more comprehensive aims and practices. In this paper, I outline the functional perspective, argue that taking the functional perspective can reveal important methodological roles for explanation in science, and consequently, that beginning here provides resources for developing more adequate responses to traditional concerns. In particular, through an examination of the ideal gas law, I emphasize the normative status of explanations within scientific communities and discuss how such status underwrites a compelling rationale for explanatory power as a theoretical virtue.     

Economic factors and the stock market: a new perspective

It has been widely accepted that many financial and economic variables are non‐linear, and neural networks can model flexible linear or non‐linear relationships among variables. The present paper deals with an important issue: Can the many studies in the finance literature evidencing predictability of stock returns by means of linear regression be improved by a neural network? We show that the predictive accuracy can be improved by a neural network, and the results largely hold out‐of‐sample. Both the neural network and linear forecasts show significant market timing ability. While the switching portfolio based on the linear forecasts outperforms the buy‐and‐hold market portfolio under all three transaction cost scenarios, the switching portfolio based on the neural network forecasts beats the market only if there is no transaction cost. Copyright © 1999 John Wiley & Sons, Ltd.     

Repertoires: A post-Kuhnian perspective on scientific change and collaborative research

We propose a framework to describe, analyze, and explain the conditions under which scientific communities organize themselves to do research, particularly within large-scale, multidisciplinary projects. The framework centers on the notion of a research repertoire, which encompasses well-aligned assemblages of the skills, behaviors, and material, social, and epistemic components that a group may use to practice certain kinds of science, and whose enactment affects the methods and results of research. This account provides an alternative to the idea of Kuhnian paradigms for understanding scientific change in the following ways: (1) it does not frame change as primarily generated and shaped by theoretical developments, but rather takes account of administrative, material, technological, and institutional innovations that contribute to change and explicitly questions whether and how such innovations accompany, underpin, and/or undercut theoretical shifts; (2) it thus allows for tracking of the organization, continuity, and coherence in research practices which Kuhn characterized as ‘normal science’ without relying on the occurrence of paradigmatic shifts and revolutions to be able to identify relevant components; and (3) it requires particular attention be paid to the performative aspects of science, whose study Kuhn pioneered but which he did not extensively conceptualize. We provide a detailed characterization of repertoires and discuss their relationship with communities, disciplines, and other forms of collaborative activities within science, building on an analysis of historical episodes and contemporary developments in the life sciences, as well as cases drawn from social and historical studies of physics, psychology, and medicine.     

Mental processes and disorders: A neurobehavioral perspective in human biometeorology

Summary Research concerning the complex relation between weather and psychological processes has emphasized three important issues: methodological problems, the determination of the major behavioral factors, and the isolation of neurobiological mechanisms. This paper reviews the current status of each issue. Weather changes are most frequently associated with behaviors that are the endpoints of inferred psychological processes that include mood, subclinical pain, anxiety, and the correlates of schedule shifts. Learning and conditioning appear to mediate a powerful influence over weather-related responses. This may explain the large individual variability in these behaviors. The most well-known group effects associated with weather changes involve psychiatric populations. Clinical subpopulations may respond in different ways to different aspects of the same weather system as well as to different types of air masses. Likely neurobiological mechanisms through which meteorogenic stimuli may mediate whole organismic effects include the locus coeruleal and limbic systems. Expected psychobiological consequences are examined in detail. The magnitude and temporal-spatial characteristics of weather effects indicate they are the subject matter of behavioral epidemiology.     

Cosmologies with varying speed of light: A historical perspective

The possibility that natural laws and constants may not be true constants, but vary over cosmic periods of time, has recently attracted much attention. In this paper, I provide some historical background to the issue and consider, in the form of a historical review, some of the more spectacular developments within recent years. The focus of the paper is on the hypothesis of a varying speed of light, which appeared shortly after the announcement of the expanding universe. After a brief account of the history of this hypothesis, I consider in more details the varying c theories that have appeared during the last decade and were originally introduced as an alternative to the inflationary model. These so-called varying speed of light (VSL) theories have been surprisingly popular and created a flood of physics and cosmology papers. However, they have also been severely criticized from conceptual points of view and their status is as yet uncertain. Although a research programme in development, a historical perspective on VSL cosmology may not be out of place.     

[FeFe] hydrogenases and their evolution: a genomic perspective

Most hydrogenases (H2ases), the enzymes that produce or oxidize dihydrogen, possess dimetallic active sites and belong to either one of two phylogenetically distinct classes, the [NiFe] and the [FeFe] H2ases. These families of H2ases share a number of similarities regarding active site structure and reaction mechanism, as a result of convergent evolution. They are otherwise alien to each other, in particular with respect to protein sequence and structure, maturation mechanisms, and distribution among the realms of life. One of the interesting features of [FeFe] H2ases is their occurrence in anaerobic bacteria, anaerobic protists, and mitochondriate eukaryotes. They thus have the potential to report on important evolutionary events, including transitions from the prokaryote to the eukaryote lifestyle. Genome sequences yield a variety of [FeFe] H2ase sequences that have been implemented to shed light on the evolution of these proteins and their host organisms.     

Mental processes and disorders: a neurobehavioral perspective in human biometeorology

Research concerning the complex relation between weather and psychological processes has emphasized three important issues: methodological problems, the determination of the major behavioral factors, and the isolation of neurobiological mechanisms. This paper reviews the current status of each issue. Weather changes are most frequently associated with behaviors that are the endpoints of inferred psychological processes that include mood, subclinical pain, anxiety, and the correlates of schedule shifts. Learning and conditioning appear to mediate a powerful influence over weather-related responses. This may explain the large individual variability in these behaviors. The most well-known group effects associated with weather changes involve psychiatric populations. Clinical subpopulations may respond in different ways to different aspects of the same weather system as well as to different types of air masses. Likely neurobiological mechanisms through which meteorogenic stimuli may mediate whole organismic effects include the locus coeruleal and limbic systems. Expected psychobiological consequences are examined in detail. The magnitude and temporal-spatial characteristics of weather effects indicate they are the subject matter of behavioral epidemiology.     

The muscle ultrastructure: a structural perspective of the sarcomere

Muscle ultrastructure is characterised by a complex arrangement of many protein-protein interactions. The sarcomere is the basic repeating unit of muscle, formed by two transverse filament systems: the thick and thin filaments. While actin and myosin are the main contractile elements of the sarcomere, other proteins act as scaffolds, control ultrastructure composition, regulate muscle contraction, and transmit tension between sarcomeres and hence to the whole myofibril. Elucidation of the structures of muscle proteins by X-ray crystallography and nuclear magnetic resonance spectroscopy has been essential in understanding muscle contraction, enabling us to relate biological to structural information. These structures reveal how components of the muscle interact, how different factors influence conformational changes within these proteins, and how mutant muscle proteins may interfere with the regulatory fine-tuning of the contractile machinery, hence leading to disease in some cases. Here, structures solved within the sarcomere have been reviewed in order to put the numerous components into context.Received 28 June 2004; received after revision 25 July 2004; accepted 28 July 2004     

Analysis and forecasting of income statement account balances the dynamic interdependency and ARIMA approaches

This paper develops a dynamic simultaneous-equations model for analyzing and forecasting the account balances in the income statement of a firm. In the model, the income statement accounts play the role of the dependent variables that are jointly determined and explained by three types of exogenous variables: non-controllable, performance, and controllable. The model is estimated by the three-stage least-squares method using annual series of data for six firms during the period from 1936 or 1950 to 1981. The immediate, delayed, and cumulated impacts of an exogenous shock on the income accounts are analyzed and the implications for managerial decisions and strategies discussed. To run as a standard of comparison for the dynamic interdependency model, the Box-Jenkins approach is also used to develop an autoregressive integrated moving average (ARIMA) model for each of the accounts. Assessing the forecasting performance of the dynamic model against a naive model and the ARIMA and Elliott-Uphoff models for the 1982-4 period beyond the estimation period, we conclude that the dynamic model is a better representation of income statement accounts of the firm and increases forecasting accuracy.     

Modular localization and the holistic structure of causal quantum theory,a historical perspective

Recent insights into the conceptual structure of localization in QFT (modular localization) led to clarifications of old unsolved problems. The oldest one is the Einstein–Jordan conundrum which led Jordan in 1925 to the discovery of quantum field theory. This comparison of fluctuations in subsystems of heat bath systems (Einstein) with those resulting from the restriction of the QFT vacuum state to an open subvolume (Jordan) leads to a perfect analogy; the globally pure vacuum state becomes upon local restriction a strongly impure KMS state. This phenomenon of localization-caused thermal behavior as well as the vacuum-polarization clouds at the causal boundary of the localization region places localization in QFT into a sharp contrast with quantum mechanics and justifies the attribute “holstic”. In fact it positions the E–J Gedankenexperiment into the same conceptual category as the cosmological constant problem and the Unruh Gedankenexperiment. The holistic structure of QFT resulting from “modular localization” also leads to a revision of the conceptual origin of the crucial crossing property which entered particle theory at the time of the bootstrap S-matrix approach but suffered from incorrect use in the S-matrix settings of the dual model and string theory.The new holistic point of view, which strengthens the autonomous aspect of QFT, also comes with new messages for gauge theory by exposing the clash between Hilbert space structure and localization and presenting alternative solutions based on the use of stringlocal fields in Hilbert space. Among other things this leads to a reformulation of the Englert–Higgs symmetry breaking mechanism.     

Molecular dialogue between the human gut microbiota and the host: a Lactobacillus and Bifidobacterium perspective

The human gut represents a highly complex ecosystem, which is densely colonized by a myriad of microorganisms that influence the physiology, immune function and health status of the host. Among the many members of the human gut microbiota, there are microorganisms that have co-evolved with their host and that are believed to exert health-promoting or probiotic effects. Probiotic bacteria isolated from the gut and other environments are commercially exploited, and although there is a growing list of health benefits provided by the consumption of such probiotics, their precise mechanisms of action have essentially remained elusive. Genomics approaches have provided exciting new opportunities for the identification of probiotic effector molecules that elicit specific responses to influence the physiology and immune function of their human host. In this review, we describe the current understanding of the intriguing relationships that exist between the human gut and key members of the gut microbiota such as bifidobacteria and lactobacilli, discussed here as prototypical groups of probiotic microorganisms.