Since the 1930s, scientists studying the neurological disease scrapie had assumed that the infectious agent was a virus. By the mid 1960s, however, several unconventional properties had arisen that were difficult to reconcile with the standard viral model. Evidence for nucleic acid within the pathogen was lacking, and some researchers considered the possibility that the infectious agent consisted solely of protein. In 1982, Stanley Prusiner coined the term `prion' to emphasize the agent's proteinaceous nature. This infectious protein hypothesis was denounced (...) by many scientists as `heretical'.This essay asks why the concept of an infectious protein was considered controversial. Some biologists justified their evaluation of this hypothesis on the grounds that an infectious protein contradicted the `central dogma of molecular biology'. Others referred to vague theoretical constraints such as molecular biology's `theoretical structure' or `framework'. Examination of the objections raised by researchers reveals exactly what generalizations were being challenged by a protein model of infection.This two-part survey of scrapie and prion research reaches several conclusions: A theoretical framework is present in molecular biology, exerting its influence in hypothesis formation and evaluation; This framework consists of several related, yet separable, generalizations or `elements', including Francis Crick's Central Dogma and Sequence Hypothesis, plus notions concerning infection, replication, protein synthesis, and protein folding; The term `central dogma' has stretched beyond Crick's original 1958 definition to encompass at least two other `framework elements': replication and protein synthesis; and From the study of scrapie and related diseases, biological information has been delineated into at least two classes: sequential and what I call `conformational'.In Part I of this essay, a brief review of the central dogma, as outlined by both Francis Crick and James Watson, will be given. The developments in scrapie research from 1965 to 1972 will then be traced. This section will summarize many of the puzzling, non-viral-like properties of the scrapie agent. Alternative hypotheses to the viral explanation will also be presented, including early versions of a protein-only hypothesis. Part II of this essay will follow the developments in scrapie and prion research from the mid 1970s through 1991. The growing prominence of a protein-only model of infection will be balanced by continued objections from many researchers to a pathogen devoid of nucleic acid. These objections will help illuminate those generalizations in molecular biology that were indeed challenged by a protein-only model of infection. (shrink)

The developing infant can accomplish all important perceptual tasks that an adult can, albeit with less skill or precision. Through infant perception research, infant responses to experiences enable researchers to reveal perceptual competence, test hypotheses about processes, and infer neural mechanisms, and researchers are able to address age-old questions about perception and the origins of knowledge.In Development of Perception in Infancy: The Cradle of Knowledge Revisited, Martha E. Arterberry and Philip J. Kellman study the methods and data of scientific (...) research on infant perception, introducing and analyzing topics through philosophical, theoretical, and historical contexts. Infant perception research is placed in a philosophical context by addressing the abilities with which humans appear to be born, those that appear to emerge due to experience, and the interaction of the two. The theoretical perspective is informed by the ecological tradition, and from such a perspective the authors focus on the information available for perception, when it is used by the developing infant, the fit between infant capabilities and environmental demands, and the role of perceptual learning. Since the original publication of this book in 1998, Arterberry and Kellman address in addition the mechanisms of change, placing the basic capacities of infants at different ages and exploring what it is that infants do with this information. Significantly, the authors feature the perceptual underpinnings of social and cognitive development, and consider two examples of atypical development - congenital cataracts and Autism Spectrum Disorder. Professionals and students alike will find this book a critical resource to understanding perception, cognitive development, social development, infancy, and developmental cognitive neuroscience, as research on the origins of perception has changed forever our conceptions of how human mental life begins. (shrink)

There is an abundant and growing feminist literature examining the implications of reproductive technologies that separate genetic, physiological, and social motherhood. The literature explains the development of these technologies in terms of the motivations of men, stressing the victimization of women by the medical and legal institutions and the commodification of these technologies. This article examines these technologies from a Marxist-Feminist perspective, locating their sources in the overall development of the forces of production; that is, in structural changes irreducible to (...) their microfoundations. In the process of changing the biological conditions of intergenerational social reproduction, these technologies have established the material basis for the structural separation between the mode of procreation and the mode of social and physical reproduction. These structural changes are generating new identities and forms of consciousness that clash with taken-for-granted ideas about motherhood. These differences are captured in feminist debates about the significance of these technologies. (shrink)

The “Perky effect” is the interference of visual imagery with vision. Studies of this effect show that visual imagery has more than symbolic properties, but these properties differ both spatially (including “pictorially”) and temporally from those of vision. We therefore reject both the literal picture-in-the-head view and the entirely symbolic view.

Developmental research on infants' categorization of living and nonliving objects finds that very young children are equally skilled in grouping such objects. The lack of a specialization for one type of object over another may be due to knowledge of function and the time frame for acquiring such knowledge.

This paper contributes to the foundations of a theory of rational choice for artificial agents in dynamic environments. Our work is developed within a theoretical framework, originally due to Bratman, that models resource-bounded agents as operating against the background of some current set of intentions, which helps to frame their subsequent reasoning. In contrast to the standard theory of rational choice, where options are evaluated in isolation, we therefore provide an analysis of situations in which the options presented to an (...) agent are evaluated against a background context provided by the agent’s current plans—commitments to future activities, which may themselves be only partially specified. The interactions between the new options and the background context can complicate the task of evaluating the option, rendering it either more or less desirable in context than it would have been in isolation.  2001 Elsevier Science B.V. All rights reserved. (shrink)

Meditation is an umbrella term for a number of mental training practices designed to improve the monitoring and regulation of attention and emotion. Some forms of meditation are now being used for clinical intervention. To accompany the increased clinical interest in meditation, research investigating the neural basis of these practices is needed. A central hypothesis of contemplative neuroscience is that meditative states, which are unique on a phenomenological level, differ on a neurophysiological level. To identify the electrophysiological correlates of meditation (...) practice, the electrical brain activity of highly skilled meditators engaging in one of six meditation styles was recorded. A mind-wandering task served as a control. Lempel–Ziv complexity showed differences in nonlinear brain dynamics during meditation compared with mind wandering, suggesting that meditation, regardless of practice, affects neural complexity. In contrast, there were no differences in power spectra at six different frequency bands, likely due to the fact that participants engaged in different meditation practices. Finally, exploratory analyses suggest neurological differences among meditation practices. These findings highlight the importance of studying the electroencephalography correlates of different meditative practices. (shrink)

Muriel Wheldale, a distinguished graduate of Newnham College, Cambridge, was a member of William Bateson's school of genetics at Cambridge University from 1903. Her investigation of flower color inheritance in snapdragons (Antirrhinum), a topic of particular interest to botanists, contributed to establishing Mendelism as a powerful new tool in studying heredity. Her understanding of the genetics of pigment formation led her to do cutting-edge work in biochemistry, culminating in the publication of her landmark work, The Anthocyanin Pigments of Plants (1916). (...) In 1915, she joined Frederick Gowland Hopkin's Department of Biochemistry as assistant and in 1926 became one of the first women to be appointed university lecturer. In 1919 she married the biochemist Huia Onslow, with whom she collaborated until his death in 1922. This paper examines Wheldale's work in genetics and especially focuses on the early linkage of Mendelian methdology with new techniques in biochemistry that eventually led to the founding of biochemical genetics. It highlights significant issues in the early history of women in genetics, including the critical role of mentors, funding opportunities, and career strategies. (shrink)

In 1987, Roy Sorensen coined the term 'parahistory' to denote the study of genuinely anachronistic artefacts delivered by time travel.¹ 'Parahistory' would thus stand to history rather as parapsychology is claimed to stand to psychology, i.e. the parahistorian would study historical data that were obtained through channels that orthodox science does not recognise. How might one establish credentials as a time traveller? What sort of evidence could a time-traveller point to in support of claims that would presumably command a great (...) deal of scepticism? While successful predictions might be one confirmatory tool, supporting evidence needn't take the form of predictions. (Although Sorensen offers an intriguing argument that a Humean about miracle-testimony would be obliged to reject any testimony to the occurrence of time travel.) Perhaps artefacts that time travellers retrieve from other times (past or future) could usefully supplement testimonial or predictive evidence for the parahistorian. However, this paper will argue, any appeal to past-artefactual evidence for parahistorical claims faces a dilemma that threatens to undermine its value: appeals to past-artefact evidence must either collapse into appeals to predictive evidence or see their value diminished by such past artefacts' necessarily exhibiting contradictory indicators of age and period. (shrink)

Around 1998, internet postings began appearing under the alias ‘ Timetravel_0 ’. This alias was later replaced by ‘John Titor’, and it's as such I'll designate the posts' author. Remarkably, Titor claimed to have time-travelled from 2036 on a mission to retrieve an IBM 5100 in 1975. Titor refrained from public appearances and any evidence for his story remains web-bound but before closing shop c. March 24 th 2001, he described various future events, e.g.: Y2K is a disaster. Many people (...) die on the highways when they freeze to death trying to get to warmer weather. Cancellation of the Olympics after 2004 due to world conflict. America will soon be engaged in civil war with itself; a civil war that we'll see the beginnings of during 2004 and 2005, escalating until it is indisputable by 2008. This equivocal civil war fizzles until global nuclear war kills three billion people in 2015. (shrink)

Mr. E. Courtney adopts Ellis's defence of repetitque, argues convincingly as a consequence that sed must be replaced by a verb, and claims: ‘That verb can hardly have been any other than stat.’ He continues : ‘This will mean that Charon's boat, having ferried across the young, does not remain tied up at the quay forgetful of the old, but goes back for them.’ The difficulty of que in the sense of sed in the line as reconstituted is defended by (...) a reference to Housman's note on Manilius, 1. 877. Still, the proposed line, non oblita tamen stat, repetitque senes, does not seem to be clear without a pause after stat, so that the reader will construe non with stat but not with repetit. This gives a very awkward rhythm indeed. (shrink)

The cognitive disorders that follow brain damage are an important source of insights into the neural bases of human thought. This work offers state-of-the-art reviews of the patient-based approach to central issues in cognitive neuroscience by leaders in the field.