325 research outputs found
Residual vectors for Alzheimer disease diagnosis and prognostication
Alzheimer disease (AD) is an increasingly prevalent neurodegenerative condition and a looming socioeconomic threat. A biomarker for the disease could make the process of diagnosis easier and more accurate, and accelerate drug discovery. The current work describes a method for scoring brain images that is inspired by fundamental principles from information retrieval (IR), a branch of computer science that includes the development of Internet search engines. For this research, a dataset of 254 baseline 18-F fluorodeoxyglucose positron emission tomography (FDG-PET) scans was obtained from the Alzheimer's Disease Neuroimaging Initiative (ADNI). For a given contrast, a subset of scans (nine of every 10) was used to compute a residual vector that typified the difference, at each voxel, between the two groups being contrasted. Scans that were not used for computing the residual vector (the remaining one of 10 scans) were then compared to the residual vector using a cosine similarity metric. This process was repeated sequentially, each time generating cosine similarity scores on 10% of the FDG-PET scans for each contrast. Statistical analysis revealed that the scores were significant predictors of functional decline as measured by the Functional Activities Questionnaire (FAQ). When logistic regression models that incorporated these scores were evaluated with leave-one-out cross-validation, cognitively normal controls were discerned from AD with sensitivity and specificity of 94.4% and 84.8%, respectively. Patients who converted from mild cognitive impairment (MCI) to AD were discerned from MCI nonconverters with sensitivity and specificity of 89.7% and 62.9%, respectively, when FAQ scores were brought into the model. Residual vectors are easy to compute and provide a simple method for scoring the similarity between an FDG-PET scan and sets of examples from a given diagnostic group. The method is readily generalizable to any imaging modality. Further interdisciplinary work between IR and clinical neuroscience is warranted
Morphology of the Reproductive System of Tetrix arenosa angusta (Hancock) (Orthoptera, Tetrigidae)
The internal reproductive organs of the male include a pair of testes, each composed of about 37 follicles and connected to a short vas efferens; a pair of vasa deferentia; about 12 paired accessory glands; a twice folded ejaculatory duct and a membranous, extensible intromittent organ. The external structures of the male include a chitinous collar, pallial complex and ninth abdominal sternum. The internal reproductive organs of the female include a pair of ovaries, each composed of 11 ovarioles; paired lateral oviducts; a short median oviduct; a terminal genital chamber; a trilobed spermatheca attached to a spermathecal gland, and a pair of median glands. The external structures of the female include the ovipositor and its related sclerites and apodemes
Concepts and Their Dynamics: A Quantum-Theoretic Modeling of Human Thought
We analyze different aspects of our quantum modeling approach of human
concepts, and more specifically focus on the quantum effects of contextuality,
interference, entanglement and emergence, illustrating how each of them makes
its appearance in specific situations of the dynamics of human concepts and
their combinations. We point out the relation of our approach, which is based
on an ontology of a concept as an entity in a state changing under influence of
a context, with the main traditional concept theories, i.e. prototype theory,
exemplar theory and theory theory. We ponder about the question why quantum
theory performs so well in its modeling of human concepts, and shed light on
this question by analyzing the role of complex amplitudes, showing how they
allow to describe interference in the statistics of measurement outcomes, while
in the traditional theories statistics of outcomes originates in classical
probability weights, without the possibility of interference. The relevance of
complex numbers, the appearance of entanglement, and the role of Fock space in
explaining contextual emergence, all as unique features of the quantum
modeling, are explicitly revealed in this paper by analyzing human concepts and
their dynamics.Comment: 31 pages, 5 figure
Quantum Aspects of Semantic Analysis and Symbolic Artificial Intelligence
Modern approaches to semanic analysis if reformulated as Hilbert-space
problems reveal formal structures known from quantum mechanics. Similar
situation is found in distributed representations of cognitive structures
developed for the purposes of neural networks. We take a closer look at
similarites and differences between the above two fields and quantum
information theory.Comment: version accepted in J. Phys. A (Letter to the Editor
Quantum Particles as Conceptual Entities: A Possible Explanatory Framework for Quantum Theory
We put forward a possible new interpretation and explanatory framework for
quantum theory. The basic hypothesis underlying this new framework is that
quantum particles are conceptual entities. More concretely, we propose that
quantum particles interact with ordinary matter, nuclei, atoms, molecules,
macroscopic material entities, measuring apparatuses, ..., in a similar way to
how human concepts interact with memory structures, human minds or artificial
memories. We analyze the most characteristic aspects of quantum theory, i.e.
entanglement and non-locality, interference and superposition, identity and
individuality in the light of this new interpretation, and we put forward a
specific explanation and understanding of these aspects. The basic hypothesis
of our framework gives rise in a natural way to a Heisenberg uncertainty
principle which introduces an understanding of the general situation of 'the
one and the many' in quantum physics. A specific view on macro and micro
different from the common one follows from the basic hypothesis and leads to an
analysis of Schrodinger's Cat paradox and the measurement problem different
from the existing ones. We reflect about the influence of this new quantum
interpretation and explanatory framework on the global nature and evolutionary
aspects of the world and human worldviews, and point out potential explanations
for specific situations, such as the generation problem in particle physics,
the confinement of quarks and the existence of dark matter.Comment: 45 pages, 10 figure
Global Ethics and Nanotechnology: A Comparison of the Nanoethics Environments of the EU and China
The following article offers a brief overview of current nanotechnology policy, regulation and ethics in Europe and The People’s Republic of China with the intent of noting (dis)similarities in approach, before focusing on the involvement of the public in science and technology policy (i.e. participatory Technology Assessment). The conclusions of this article are, that (a) in terms of nanosafety as expressed through policy and regulation, China PR and the EU have similar approaches towards, and concerns about, nanotoxicity—the official debate on benefits and risks is not markedly different in the two regions; (b) that there is a similar economic drive behind both regions’ approach to nanodevelopment, the difference being the degree of public concern admitted; and (c) participation in decision-making is fundamentally different in the two regions. Thus in China PR, the focus is on the responsibility of the scientist; in the EU, it is about government accountability to the public. The formulation of a Code of Conduct for scientists in both regions (China PR’s predicted for 2012) reveals both similarity and difference in approach to nanotechnology development. This may change, since individual responsibility alone cannot guide S&T development, and as public participation is increasingly seen globally as integral to governmental decision-making
“Am I my genes?”: Questions of identity among individuals confronting genetic disease
Purpose: To explore many questions raised by genetics concerning personal identities that have not been fully investigated.
Methods: We interviewed in depth, for 2 hours each, 64 individuals who had or were at risk for Huntington disease, breast cancer, or alpha-1 antitrypsin deficiency.
Results: These individuals struggled with several difficult issues of identity. They drew on a range of genotypes and phenotypes (e.g., family history alone; mutations, but no symptoms; or symptoms). They often felt that their predicament did not fit preexisting categories well (e.g., “sick,” “healthy,” “disabled,” “predisposed”), due in part to uncertainties involved (e.g., unclear prognoses, since mutations may not produce symptoms). Hence, individuals varied in how much genetics affected their identity, in what ways, and how negatively. Factors emerged related to disease, family history, and other sources of identity. These identities may, in turn, shape disclosure, coping, and other health decisions.
Conclusions: Individuals struggle to construct a genetic identity. They view genetic information in highly subjective ways, varying widely in what aspects of genetic information they focus on and how. These data have important implications for education of providers (to assist patients with these issues), patients, and family members; and for research, to understand these issues more fully
Human Embryos and Eggs::From long-term storage to biobanking
Genetic relatedness poses significant challenges to traditional practices of medical ethics as concerns the biobanking of human biological samples. In this paper, we first outline the ethical challenges to informed consent and confidentiality as these apply to human biobanks, irrespective of the type of tissue being stored. We argue that the shared nature of genetic information has clear implications for informed consent, and the identifying nature of biological samples and information has clear implications for promises of confidentiality. Next, with regard to the special case of biobanking human embryos and eggs, we consider issues arising from: first, the type of tissues being stored; second, the use to which these tissues are put; and third, how this plays out given the shared and identifying nature of these tissues. Specifically, we examine the differences between human bodily tissues and human reproductive tissues focusing on the assumed potential of the reproductive tissues and on the possible greater emotional attachment to these tissues because of their real and imagined kinship. For some donors there may be a sense of family connection with embryos and eggs they once thought of as ‘children-in-waiting’. Finally, we conclude by considering the implications for ethical practice
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