765 research outputs found

    Foucault's critical psychiatry and the spirit of the Enlightenment: a historico-philosophical study of psychiatry and its limits

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    My thesis revolves around three axes: the Foucauldian critical-historical method, its relationship with enlightenment critique and the way this critique is implemented in Foucault’s seminal work, History of Madness. Foucault’s exploration of the origins of psychiatry applies his own theories of power, truth and reason and draws on Kant’s philosophy, shedding new light on the way we perceive the birth and development of psychiatric practice. Following Foucault’s adoption of ‘limit attitude’, which investigates the limits of our thinking as points of disruption and renewal of established frames of reference, the thesis aims to dispel the widely accepted belief that psychiatry represents the triumph of rationalism by somehow conquering madness and turning it into an object of neutral, scientific perception. A history of limits examines the birth of psychiatry in its full complexity: in the late eighteenth century, doctors were not simply rationalists but also alienists, philosophers of finitude who recognized madness as an experience at the limits of reason, introducing a discourse which conditioned the formation of psychiatry as a type of medical activity. Since that event, the same type of recognition, the same anthropological confrontation with madness has persisted beneath the calm development of psychiatric rationality, undermining the supposed linearity, absolute authority and steady progress of psychiatric positivism. Foucault’s critique foregrounds this anthropological problematic as indispensable for psychiatry, encouraging psychiatrists to become aware of the epistemological limitations of their practice, and also to review the ethical and political issues which madness introduces into the apparent neutrality of current psychiatric discourse

    Entropic Elasticity of Double-Strand DNA Subject to Simple Spatial Constraints

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    The aim of the present paper is the study of the entropic elasticity of the dsDNA molecule, having a cristallographic length L of the order of 10 to 30 persistence lengths A, when it is subject to spatial obstructions. We have not tried to obtain the single molecule partition function by solving a Schodringer-like equation. We prefer to stay within a discretized version of the WLC model with an added one-monomer potential, simulating the spatial constraints. We derived directly from the discretized Boltzmann formula the transfer matrix connecting the partition functions relative to adjacent "effective monomers". We have plugged adequate Dirac delta-functions in the functional integral to ensure that the monomer coordinate and the tangent vector are independent variables. The partition function is, then, given by an iterative process which is both numerically efficient and physically transparent. As a test of our discretized approach, we have studied two configurations involving a dsDNA molecule confined between a pair of parallel plates.Comment: The most formal developments of Section I have been moved into an appendix and replaced by a direct derivation of the transfer matrix used in the applications. of Section II. Two paragraphs and two figures have been added to clarify the physical interpretation of the result

    Polaron Variational Methods In The Particle Representation Of Field Theory : II. Numerical Results For The Propagator

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    For the scalar Wick-Cutkosky model in the particle representation we perform a similar variational calculation for the 2-point function as was done by Feynman for the polaron problem. We employ a quadratic nonlocal trial action with a retardation function for which several ans\"atze are used. The variational parameters are determined by minimizing the variational function and in the most general case the nonlinear variational equations are solved numerically. We obtain the residue at the pole, study analytically and numerically the instability of the model at larger coupling constants and calculate the width of the dressed particle.Comment: 25 pages standard LaTeX, 9 uuencoded postscript figures embedded with psfig.st

    Derivative expansion of quadratic operators in a general 't Hooft gauge

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    A derivative expansion technique is developed to compute functional determinants of quadratic operators, non diagonal in spacetime indices. This kind of operators arise in general 't Hooft gauge fixed Lagrangians. Elaborate applications of the developed derivative expansion are presented.Comment: 40 pages, to appear in Phys. Rev.

    One Loop Back Reaction On Power Law Inflation

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    We consider quantum mechanical corrections to a homogeneous, isotropic and spatially flat geometry whose scale factor expands classically as a general power of the co-moving time. The effects of both gravitons and the scalar inflaton are computed at one loop using the manifestly causal formalism of Schwinger with the Feynman rules recently developed by Iliopoulos {\it et al.} We find no significant effect, in marked contrast with the result obtained by Mukhanov {\it et al.} for chaotic inflation based on a quadratic potential. By applying the canonical technique of Mukhanov {\it et al.} to the exponential potentials of power law inflation, we show that the two methods produce the same results, within the approximations employed, for these backgrounds. We therefore conclude that the shape of the inflaton potential can have an enormous impact on the one loop back-reaction.Comment: 28 pages, LaTeX 2 epsilo

    Transcriptomic and CRISPR/Cas9 technologies reveal FOXA2 as a tumor suppressor gene in pancreatic cancer

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    Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with low survival rates and limited therapeutic options. Thus elucidation of signaling pathways involved in PDAC pathogenesis is essential for identifying novel potential therapeutic gene targets. Here, we used a systems approach to elucidate those pathways by integrating gene and microRNA profiling analyses together with CRISPR/Cas9 technology to identify novel transcription factors involved in PDAC pathogenesis. FOXA2 transcription factor was found to be significantly downregulated in PDAC relative to control pancreatic tissues. Functional experiments revealed that FOXA2 has a tumor suppressor function through inhibition of pancreatic cancer cell growth, migration, invasion, and colony formation. In situ hybridization analysis revealed miR-199a to be significantly upregulated in pancreatic cancer. Bioinformatics and luciferase analyses showed that miR-199a negatively but directly regulates FOXA2 expression through binding in its 3′-untranslated region (UTR). Evaluation of the functional importance of miR-199a on pancreatic cancer revealed that miR-199a acts as an inhibitor of FOXA2 expression, inducing an increase in pancreatic cancer cell proliferation, migration, and invasion. Additionally, gene ontology and network analyses in PANC-1 cells treated with a small interfering RNA (siRNA) against FOXA2 revealed an enrichment for cell invasion mechanisms through PLAUR and ERK activation. FOXA2 deletion (FOXA2Δ) by using two CRISPR/Cas9 vectors in PANC-1 cells induced tumor growth in vivo resulting in upregulation of PLAUR and ERK pathways in FOXA2Δ xenograft tumors. We have identified FOXA2 as a novel tumor suppressor in pancreatic cancer and it is regulated directly by miR-199a, thereby enhancing our understanding of how microRNAs interplay with the transcription factors to affect pancreatic oncogenesis

    The Robustness of Quintessence

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    Recent observations seem to suggest that our Universe is accelerating implying that it is dominated by a fluid whose equation of state is negative. Quintessence is a possible explanation. In particular, the concept of tracking solutions permits to adress the fine-tuning and coincidence problems. We study this proposal in the simplest case of an inverse power potential and investigate its robustness to corrections. We show that quintessence is not affected by the one-loop quantum corrections. In the supersymmetric case where the quintessential potential is motivated by non-perturbative effects in gauge theories, we consider the curvature effects and the K\"ahler corrections. We find that the curvature effects are negligible while the K\"ahler corrections modify the early evolution of the quintessence field. Finally we study the supergravity corrections and show that they must be taken into account as QmPlQ\approx m_{\rm Pl} at small red-shifts. We discuss simple supergravity models exhibiting the quintessential behaviour. In particular, we propose a model where the scalar potential is given by V(Q)=Λ4+αQαeκ2Q2V(Q)=\frac{\Lambda^{4+\alpha }}{Q^{\alpha}}e^{\frac{\kappa}{2}Q^2}. We argue that the fine-tuning problem can be overcome if α11\alpha \ge 11. This model leads to ωQ0.82\omega_Q\approx -0.82 for Ωm0.3\Omega_{\rm m}\approx 0.3 which is in good agreement with the presently available data.Comment: 16 pages, 7 figure

    One Loop Back Reaction On Chaotic Inflation

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    We extend, for the case of a general scalar potential, the inflaton-graviton Feynman rules recently developed by Iliopoulos {\it et al.} As an application we compute the leading term, for late co-moving times, of the one loop back reaction on the expansion rate for V(ϕ)=12m2ϕ2V(\phi) = \frac12 m^2 \phi^2. This is expressed as the logarithmic time derivative of the scale factor in the coordinate system for which the expectation value of the metric has the form: dxμdxν=dtˉ2+a2(tˉ)dxdx dx^{\mu} dx^{\nu} = - d{\bar t}^2 + a^2({\bar t}) d{\vec x} \cdot d{\vec x}. This quantity should be a gauge independent observable. Our result for it agrees exactly with that inferred from the effect previously computed by Mukhanov {\it et al.} using canonical quantization. It is significant that the two calculations were made with completely different schemes for fixing the gauge, and that our computation was done using the standard formalism of covariant quantization. This should settle some of the issues recently raised by Unruh.Comment: 41 pages, LaTeX 2 epsilo
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