Biological Individuals

The impressive variation amongst biological individuals generates many complexities in addressing the simple-sounding question what is a biological individual? A distinction between evolutionary and physiological individuals is useful in thinking about biological individuals, as is attention to the kinds of groups, such as superorganisms and species, that have sometimes been thought of as biological individuals. More fully understanding the conceptual space that biological individuals occupy also involves considering a range of other concepts, such as life, reproduction, and agency. There has been a focus in some recent discussions by both philosophers and biologists on how evolutionary individuals are created and regulated, as well as continuing work on the evolution of individuality

Well-being, Disability, and Choosing Children

The view that it is better for life to be created free of disability is pervasive in both common sense and philosophy. We cast doubt on this view by focusing on an influential line of thinking that manifests it. That thinking begins with a widely-discussed principle, Procreative Beneficence, and draws conclusions about parental choice and disability. After reconstructing two versions of this argument, we critique the first by exploring the relationship between different understandings of well-being and disability, and the second by more briefly focusing on the idea of a significant reason. By placing these results against the broader historical and ongoing contexts in which the lives of those with disabilities have been deemed of inferior quality, we conclude with a call for greater humility about disability and well-being in thought and practice

Cohesion, Gene flow, and the Nature of Species

A far-reaching and influential view in evolutionary biology claims that species are cohesive units held together by gene flow. Biologists have recognized empirical problems facing this view; after sharpening the expression of the view, we present novel conceptual problems for it. At the heart of these problems is a distinction between two importantly different concepts of cohesion, what we call integrative and response cohesion. Acknowledging the distinction problematizes both the explanandum of species cohesion and the explanans of gene flow that are central to the view we discuss. We conclude by tracing four broader implications for the study and conceptualization of species

Developmental sensory experience balances cortical excitation and inhibition.

Early in life, neural circuits are highly susceptible to outside influences. The organization of the primary auditory cortex (A1) in particular is governed by acoustic experience during the critical period, an epoch near the beginning of postnatal development throughout which cortical synapses and networks are especially plastic. This neonatal sensitivity to the pattern of sensory inputs is believed to be essential for constructing stable and adequately adapted representations of the auditory world and for the acquisition of language skills by children. One important principle of synaptic organization in mature brains is the balance between excitation and inhibition, which controls receptive field structure and spatiotemporal flow of neural activity, but it is unknown how and when this excitatory-inhibitory balance is initially established and calibrated. Here we use whole-cell recording to determine the processes underlying the development of synaptic receptive fields in rat A1. We find that, immediately after the onset of hearing, sensory-evoked excitatory and inhibitory responses are equally strong, although inhibition is less stimulus-selective and mismatched with excitation. However, during the third week of postnatal development, excitation and inhibition become highly correlated. Patterned sensory stimulation drives coordinated synaptic changes across receptive fields, rapidly improves excitatory-inhibitory coupling and prevents further exposure-induced modifications. Thus, the pace of cortical synaptic receptive field development is set by progressive, experience-dependent refinement of intracortical inhibition

Reading Instruction for Children who use AAC: Considerations in the Pursuit of Generalizable Results

Our purpose was to review evidence-based literacy instruction for children with severe speech impairment (SSI) who communicate with AAC. This review focuses on three issues important to researchers in this area: participant heterogeneity, assessment and instruction, and research design. We found 8 articles that reported attempts to teach phonological awareness and individual-word reading to a total of 26 children with SSI who used AAC. We evaluated these studies based on reporting of participant characteristics, assessment and instruction modifications, and the strength of research designs. We conclude by highlighting the need for standard assessments that can be used across studies, discussing strategies for facilitating metaanalyses, and suggesting the creation of an online database for researchers to share results on literacy instruction for this population

Immunoregulatory soluble CTLA-4 modifies effector T cell responses in systemic lupus erythematosus

Acknowledgments This work was supported by Arthritis Research UK (Grant no. 19282). We are grateful to Dr. Nick Fluck for his invaluable support in recruiting patients for the study, and Mrs. Vivien Vaughan for her invaluable expertise in recruiting study participants and maintaining ethical documentation.Peer reviewedPublisher PD

Geographical Distributions, Relative Abundance and Coexistence of Drosophila aldrichi and Drosophila buzzatii in Australia

Climatic data and collection records for the cactophilic Drosophila aldrichi and Drosophila buzzatii for 97 localities were used to examine the effects of geographical location, season, host plant species and climatic factors on their range and relative abundance. Temporal variation in relative abundance was assessed from monthly collections over 4 years at one locality. Effects of weather variables over the 28 days before each collection were examined. A generalized linear model of the spatial data showed significant geographical variation in relative abundance, and significant climatic effects, with the proportion of D. aldrichi higher in the warm season, and increasing as temperature variation decreased and moisture indices increased. The temporal data gave generally concordant results, as D. aldrichi proportion was higher in summer and autumn, and increased as maximum and minimum temperatures increased, and as variation in maximum temperature decreased. In a laboratory competition experiment, D. aldrichi eliminated D. buzzatii at 31°C, but was itself eliminated at 18°C and 25°C. The range of D. buzzatii is constrained only by availability of its host plant, Opuntia species, although its relative abundance is reduced in the northern part of its distribution. The range of D. aldrichi, from central Queensland to northern NSW, Australia, is entirely within that of D. buzzatii, and its relative abundance decreases from north to south. Both climate and weather, particularly temperature variability, have direct effects on the relative abundances of the two species, and both likely act indirectly by influencing the outcome of interspecific competition

Mechanical Faraday effect for orbital angular momentum-carrying beams

When linearly polarised light is transmitted through a spinning window, the plane of polarisation is rotated. This rotation arises through a phase change that is applied to the circularly polarised states corresponding to the spin angular momentum (SAM). Here we show an analogous effect for the orbital angular momentum (OAM), where a differential phase between the positive and negative modes (±ℓ) is observed as a rotation of the transmitted image. For normal materials, this rotation is on the order of a micro radian, but by using a slow-light medium, we show a rotation of a few degrees. We also note that, within the bounds of our experimental parameters, this rotation angle does not exceed the scale of the spatial features in the beam profile

Modern Pulsed Power: Charlie Martin and Beyond

International Symposium on New Paradigm VLSI Computing, Sendai, Japan, Dec. 12-14, 2002, pp.31-36.This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. As such, it is in the public domain, and under the provisions of Title 17, United States Code, Section 105, may not be copyrighted.Modern pulsed power has its genesis in the pioneering work of the late John Christopher Martin and his colleagues at the Atomic Weapons Establishment, Aldermaston, U.K., in the 1960s [1]. “Charlie,” as he was known to the community, was a hydrodynamicist who was frustrated by his inability to purchase an adequate X-ray radiography source to image the dynamic phenomena he was interested in. As a result, he pursued a new generation of radiography sources that were based on high-power Marx generators, coupled with low-impedance transmission lines, and cold cathode single-stage accelerating gaps. Thus was the birth of modern pulsed power.U. S. Army Research OfficeSponsor/Monitor's Report Number(s):42713.8-PHDAAD19-01-1-069