753 research outputs found
Renormalization in general theories with inter-generation mixing
We derive general and explicit expressions for the unrenormalized and
renormalized dressed propagators of fermions in parity-nonconserving theories
with inter-generation mixing. The mass eigenvalues, the corresponding mass
counterterms, and the effect of inter-generation mixing on their determination
are discussed. Invoking the Aoki-Hioki-Kawabe-Konuma-Muta renormalization
conditions and employing a number of very useful relations from Matrix Algebra,
we show explicitly that the renormalized dressed propagators satisfy important
physical properties.Comment: 14 pages; to appear in Phys. Rev.
Several types of types in programming languages
Types are an important part of any modern programming language, but we often
forget that the concept of type we understand nowadays is not the same it was
perceived in the sixties. Moreover, we conflate the concept of "type" in
programming languages with the concept of the same name in mathematical logic,
an identification that is only the result of the convergence of two different
paths, which started apart with different aims. The paper will present several
remarks (some historical, some of more conceptual character) on the subject, as
a basis for a further investigation. The thesis we will argue is that there are
three different characters at play in programming languages, all of them now
called types: the technical concept used in language design to guide
implementation; the general abstraction mechanism used as a modelling tool; the
classifying tool inherited from mathematical logic. We will suggest three
possible dates ad quem for their presence in the programming language
literature, suggesting that the emergence of the concept of type in computer
science is relatively independent from the logical tradition, until the
Curry-Howard isomorphism will make an explicit bridge between them.Comment: History and Philosophy of Computing, HAPOC 2015. To appear in LNC
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Label-free, live optical imaging of reprogrammed bipolar disorder patient-derived cells reveals a functional correlate of lithium responsiveness
Development of novel treatments and diagnostic tools for psychiatric illness has been hindered by the absence of cellular models of disease. With the advent of cellular reprogramming, it may be possible to recapitulate the disease biology of psychiatric disorders using patient skin cells transdifferentiated to neurons. However, efficiently identifying and characterizing relevant neuronal phenotypes in the absence of well-defined pathophysiology remains a challenge. In this study, we collected fibroblast samples from patients with bipolar 1 disorder, characterized by their lithium response (n=12), and healthy control subjects (n=6). We identified a cellular phenotype in reprogrammed neurons using a label-free imaging assay based on a nanostructured photonic crystal biosensor and found that an optical measure of cell adhesion was associated with clinical response to lithium treatment. This cellular phenotype may represent a useful biomarker to evaluate drug response and screen for novel therapeutics
Subject preferences of fifth-grade children.
Thesis (Ed.M.)--Boston University
N.B.:Pages 155 and 309 are missing from original thesis
Cognitive behavioral therapy for insomnia comorbid with COPD is feasible with preliminary evidence of positive sleep and fatigue effects
Background: Many people with COPD report difficulties falling asleep or staying asleep, insufficient sleep duration, or nonrestorative sleep. Cognitive behavioral therapy for insomnia (CBT-I) has proved effective not only in people with primary insomnia but also in people with insomnia comorbid with psychiatric and medical illness (eg, depression, cancer, and chronic pain). However, CBT-I has rarely been tested in those with COPD who have disease-related features that interfere with sleep and may lessen the effectiveness of such therapies. The purpose of this study was to determine the feasibility of applying a CBT-I intervention for people with COPD and to assess the impact of CBT-I on insomnia severity and sleep-related outcomes,
fatigue, mood, and daytime functioning.
Methods: The study had two phases. In Phase 1, a 6-weekly session CBT-I intervention protocol in participants with COPD was assessed to examine feasibility and acceptability. Phase 2 was a small trial utilizing a prospective two-group pre- and post-test design with random assignment to the six-session CBT-I or a six-session wellness education (WE) program to determine the effects of each intervention, with both interventions being provided by a nurse behavioral sleep medicine specialist.
Results: Fourteen participants (five in Phase 1 and nine in Phase 2) completed six sessions
of CBT-I and nine participants completed six sessions of WE. Participants indicated that both interventions were acceptable. Significant positive treatment-related effects of the CBT-I intervention were noted for insomnia severity (P = 0.000), global sleep quality (P = 0.002), wake after sleep onset (P = 0.03), sleep efficiency (P = 0.02), fatigue (P = 0.005), and beliefs and attitudes about sleep (P = 0.000). Significant positive effects were noted for depressed mood after WE (P = 0.005).
Conclusion: Results suggest that using CBT-I in COPD is feasible and the outcomes compare
favorably with those obtained in older adults with insomnia in the context of other chronic
illnesses
Towards the clinical implementation of pharmacogenetics in bipolar disorder.
BackgroundBipolar disorder (BD) is a psychiatric illness defined by pathological alterations between the mood states of mania and depression, causing disability, imposing healthcare costs and elevating the risk of suicide. Although effective treatments for BD exist, variability in outcomes leads to a large number of treatment failures, typically followed by a trial and error process of medication switches that can take years. Pharmacogenetic testing (PGT), by tailoring drug choice to an individual, may personalize and expedite treatment so as to identify more rapidly medications well suited to individual BD patients.DiscussionA number of associations have been made in BD between medication response phenotypes and specific genetic markers. However, to date clinical adoption of PGT has been limited, often citing questions that must be answered before it can be widely utilized. These include: What are the requirements of supporting evidence? How large is a clinically relevant effect? What degree of specificity and sensitivity are required? Does a given marker influence decision making and have clinical utility? In many cases, the answers to these questions remain unknown, and ultimately, the question of whether PGT is valid and useful must be determined empirically. Towards this aim, we have reviewed the literature and selected drug-genotype associations with the strongest evidence for utility in BD.SummaryBased upon these findings, we propose a preliminary panel for use in PGT, and a method by which the results of a PGT panel can be integrated for clinical interpretation. Finally, we argue that based on the sufficiency of accumulated evidence, PGT implementation studies are now warranted. We propose and discuss the design for a randomized clinical trial to test the use of PGT in the treatment of BD
Dysregulated protocadherin-pathway activity as an intrinsic defect in induced pluripotent stem cell-derived cortical interneurons from subjects with schizophrenia.
We generated cortical interneurons (cINs) from induced pluripotent stem cells derived from 14 healthy controls and 14 subjects with schizophrenia. Both healthy control cINs and schizophrenia cINs were authentic, fired spontaneously, received functional excitatory inputs from host neurons, and induced GABA-mediated inhibition in host neurons in vivo. However, schizophrenia cINs had dysregulated expression of protocadherin genes, which lie within documented schizophrenia loci. Mice lacking protocadherin-α showed defective arborization and synaptic density of prefrontal cortex cINs and behavioral abnormalities. Schizophrenia cINs similarly showed defects in synaptic density and arborization that were reversed by inhibitors of protein kinase C, a downstream kinase in the protocadherin pathway. These findings reveal an intrinsic abnormality in schizophrenia cINs in the absence of any circuit-driven pathology. They also demonstrate the utility of homogenous and functional populations of a relevant neuronal subtype for probing pathogenesis mechanisms during development
The Functional DRD3 Ser9Gly Polymorphism (rs6280) Is Pleiotropic, Affecting Reward as Well as Movement
Abnormalities of motivation and behavior in the context of reward are a fundamental component of addiction and mood disorders. Here we test the effect of a functional missense mutation in the dopamine 3 receptor (DRD3) gene (ser9gly, rs6280) on reward-associated dopamine (DA) release in the striatum. Twenty-six healthy controls (HCs) and 10 unmedicated subjects with major depressive disorder (MDD) completed two positron emission tomography (PET) scans with [11C]raclopride using the bolus plus constant infusion method. On one occasion subjects completed a sensorimotor task (control condition) and on another occasion subjects completed a gambling task (reward condition). A linear regression analysis controlling for age, sex, diagnosis, and self-reported anhedonia indicated that during receipt of unpredictable monetary reward the glycine allele was associated with a greater reduction in D2/3 receptor binding (i.e., increased reward-related DA release) in the middle (anterior) caudate (p<0.01) and the ventral striatum (p<0.05). The possible functional effect of the ser9gly polymorphism on DA release is consistent with previous work demonstrating that the glycine allele yields D3 autoreceptors that have a higher affinity for DA and display more robust intracellular signaling. Preclinical evidence indicates that chronic stress and aversive stimulation induce activation of the DA system, raising the possibility that the glycine allele, by virtue of its facilitatory effect on striatal DA release, increases susceptibility to hyperdopaminergic responses that have previously been associated with stress, addiction, and psychosis
A Behavioural Foundation for Natural Computing and a Programmability Test
What does it mean to claim that a physical or natural system computes? One
answer, endorsed here, is that computing is about programming a system to
behave in different ways. This paper offers an account of what it means for a
physical system to compute based on this notion. It proposes a behavioural
characterisation of computing in terms of a measure of programmability, which
reflects a system's ability to react to external stimuli. The proposed measure
of programmability is useful for classifying computers in terms of the apparent
algorithmic complexity of their evolution in time. I make some specific
proposals in this connection and discuss this approach in the context of other
behavioural approaches, notably Turing's test of machine intelligence. I also
anticipate possible objections and consider the applicability of these
proposals to the task of relating abstract computation to nature-like
computation.Comment: 37 pages, 4 figures. Based on an invited Talk at the Symposium on
Natural/Unconventional Computing and its Philosophical Significance, Alan
Turing World Congress 2012, Birmingham, UK.
http://link.springer.com/article/10.1007/s13347-012-0095-2 Ref. glitch fixed
in 2nd. version; Philosophy & Technology (special issue on History and
Philosophy of Computing), Springer, 201
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