321 research outputs found

    Cytokines as a stressor: Implications for depressive illness

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    Stressful events have been implicated in the provocation of depressive illness. Inasmuch as immunological challenge, and particularly cytokine administration, engender neuroendocrine and central neurochemical changes reminiscent of those provoked by psychogenic stressors, it was suggested that immune activation may also contribute to affective illness. The present report provides a brief overview of the neurochemical sequelae of acute and repeated interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α) and IL-2 treatment, describes some of the synergisms associated with these treatments, as well as their potential interactions with psychogenic stressors. In addition, a discussion is provided concerning the fact that cytokines, like stressors, may have time-dependent proactive effects, so that re-exposure to the treatments provoke greatly augmented neurochemical changes (sensitization). Given that the effects of cytokines are evident within hypothalamic, as well as extrahypothalamic sites, including various limbic regions, it is suggested that cytokines may impact on emotional changes, including depression

    Nature of light correlations in ghost imaging

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    We investigate the nature of correlations in Gaussian light sources used for ghost imaging. We adopt methods from quantum information theory to distinguish genuinely quantum from classical correlations. Combining a microscopic analysis of speckle-speckle correlations with an effective coarse-grained description of the beams, we show that quantum correlations exist even in `classical'-like thermal light sources, and appear relevant for the implementation of ghost imaging in the regime of low illumination. We further demonstrate that the total correlations in the thermal source beams effectively determine the quality of the imaging, as quantified by the signal-to-noise ratio.Comment: 12 pages, 5 figures. To appear in Scientific Reports (NPG

    Free Will in a Quantum World?

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    In this paper, I argue that Conway and Kochen’s Free Will Theorem (1,2) to the conclusion that quantum mechanics and relativity entail freedom for the particles, does not change the situation in favor of a libertarian position as they would like. In fact, the theorem more or less implicitly assumes that people are free, and thus it begs the question. Moreover, it does not prove neither that if people are free, so are particles, nor that the property people possess when they are said to be free is the same as the one particles possess when they are claimed to be free. I then analyze the Free State Theorem (2), which generalizes the Free Will Theorem without the assumption that people are free, and I show that it does not prove anything about free will, since the notion of freedom for particles is either inconsistent, or it does not concern our common understanding of freedom. In both cases, the Free Will Theorem and the Free State Theorem do not provide any enlightenment on the constraints physics can pose on free will

    Chaste: an open source C++ library for computational physiology and biology

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    Chaste - Cancer, Heart And Soft Tissue Environment - is an open source C++ library for the computational simulation of mathematical models developed for physiology and biology. Code development has been driven by two initial applications: cardiac electrophysiology and cancer development. A large number of cardiac electrophysiology studies have been enabled and performed, including high performance computational investigations of defibrillation on realistic human cardiac geometries. New models for the initiation and growth of tumours have been developed. In particular, cell-based simulations have provided novel insight into the role of stem cells in the colorectal crypt. Chaste is constantly evolving and is now being applied to a far wider range of problems. The code provides modules for handling common scientific computing components, such as meshes and solvers for ordinary and partial differential equations (ODEs/PDEs). Re-use of these components avoids the need for researchers to "re-invent the wheel" with each new project, accelerating the rate of progress in new applications. Chaste is developed using industrially-derived techniques, in particular test-driven development, to ensure code quality, re-use and reliability. In this article we provide examples that illustrate the types of problems Chaste can be used to solve, which can be run on a desktop computer. We highlight some scientific studies that have used or are using Chaste, and the insights they have provided. The source code, both for specific releases and the development version, is available to download under an open source Berkeley Software Distribution (BSD) licence at http://www.cs.ox.ac.uk/chaste, together with details of a mailing list and links to documentation and tutorials

    Magnetism, FeS colloids, and Origins of Life

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    A number of features of living systems: reversible interactions and weak bonds underlying motor-dynamics; gel-sol transitions; cellular connected fractal organization; asymmetry in interactions and organization; quantum coherent phenomena; to name some, can have a natural accounting via physicalphysical interactions, which we therefore seek to incorporate by expanding the horizons of `chemistry-only' approaches to the origins of life. It is suggested that the magnetic 'face' of the minerals from the inorganic world, recognized to have played a pivotal role in initiating Life, may throw light on some of these issues. A magnetic environment in the form of rocks in the Hadean Ocean could have enabled the accretion and therefore an ordered confinement of super-paramagnetic colloids within a structured phase. A moderate H-field can help magnetic nano-particles to not only overcome thermal fluctuations but also harness them. Such controlled dynamics brings in the possibility of accessing quantum effects, which together with frustrations in magnetic ordering and hysteresis (a natural mechanism for a primitive memory) could throw light on the birth of biological information which, as Abel argues, requires a combination of order and complexity. This scenario gains strength from observations of scale-free framboidal forms of the greigite mineral, with a magnetic basis of assembly. And greigite's metabolic potential plays a key role in the mound scenario of Russell and coworkers-an expansion of which is suggested for including magnetism.Comment: 42 pages, 5 figures, to be published in A.R. Memorial volume, Ed Krishnaswami Alladi, Springer 201

    Gastrin-Releasing Peptide Signaling Plays a Limited and Subtle Role in Amygdala Physiology and Aversive Memory

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    Links between synaptic plasticity in the lateral amygdala (LA) and Pavlovian fear learning are well established. Neuropeptides including gastrin-releasing peptide (GRP) can modulate LA function. GRP increases inhibition in the LA and mice lacking the GRP receptor (GRPR KO) show more pronounced and persistent fear after single-trial associative learning. Here, we confirmed these initial findings and examined whether they extrapolate to more aspects of amygdala physiology and to other forms of aversive associative learning. GRP application in brain slices from wildtype but not GRPR KO mice increased spontaneous inhibitory activity in LA pyramidal neurons. In amygdala slices from GRPR KO mice, GRP did not increase inhibitory activity. In comparison to wildtype, short- but not long-term plasticity was increased in the cortico-lateral amygdala (LA) pathway of GRPR KO amygdala slices, whereas no changes were detected in the thalamo-LA pathway. In addition, GRPR KO mice showed enhanced fear evoked by single-trial conditioning and reduced spontaneous firing of neurons in the central nucleus of the amygdala (CeA). Altogether, these results are consistent with a potentially important modulatory role of GRP/GRPR signaling in the amygdala. However, administration of GRP or the GRPR antagonist (D-Phe6, Leu-NHEt13, des-Met14)-Bombesin (6–14) did not affect amygdala LTP in brain slices, nor did they affect the expression of conditioned fear following intra-amygdala administration. GRPR KO mice also failed to show differences in fear expression and extinction after multiple-trial fear conditioning, and there were no differences in conditioned taste aversion or gustatory neophobia. Collectively, our data indicate that GRP/GRPR signaling modulates amygdala physiology in a paradigm-specific fashion that likely is insufficient to generate therapeutic effects across amygdala-dependent disorders

    Pluralitas Agama dalam Keluarga Jawa

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    Dalam masyarakat Jawa terdapat pemahaman dan pemaknaan sendiri terhadap agama yaitu â€agami ageming ajiâ€. Artinya apa pun agama yang dipeluk sama saja karena semua agama mengajarkan keselamatan. Oleh sebab itu menjadi sebuah fenomena menarik di kalangan masyarakat Jawa karena mereka cenderung lebih toleran dalam menyikapi perbedaaan dan keragaman beragama. Salah satu contoh masyarakat yang menghargai pluralitas agama adalah masyarakat Desa Getas Kaloran Temanggung. Tujuan penelitian ini adalah untuk menjelaskan tentang sejumlah keluarga yang dapat menerima pluralitas agama dan toleransi terhadap pluralitas agama dalam keluarga Jawa. Tulisan ini merupakan hasil penelitian yang menggunakan pendekatan deskriptif kualitatif. Subyek penelitian adalah masyarakat Desa Getas yang memiliki keragaman agama dalam keluarganya. Berdasarkan hasil penelitian dapat disimpulkan bahwa masyarakat Desa Getas dapat menerima pluralitas agama karena menurut mereka agama adalah urusan pribadi seseorang jadi tidak ada pihak yang dapat memaksakan suatu keyakinan kepada individu lain. Pluralitas agama tersebut tidak menimbulkan masalah berarti karena masyarakat memiliki derajat toleransi yang tinggi antar anggota keluarga, yang ditunjukkan melalui saling menghargai dan mengormati dan tidak mencampuri urusan keagamaan orang lain, serta saling membantu antar anggota keluarga untuk memperlancar kegiatan ibadah masing – masing. In Javanese community there is a specific principle on the meaning of religion, namely â€agami ageming ajiâ€. This pilosophy means whatever religion people believe, it doesn’t matter because they all teach salvation. This is an interesting phenomenon among the Javanese community because they tend to be tolerant in dealing with differences and diversity of religion that happen in one household. The objective of this article is to discuss the practices of religious tolerance found in a rural community of Getas, Kaloran, Temanggung Central Java. Techniques of data collection is done by interviews and observation. The study subjects were villagers of Getas, which has a diversity of religion in families. Based on the research results, it can be concluded that the villagers embrace a tradition of religious pluralism because they think religion is one’s personal affairs so that no party can impose a conviction for another individual. The plurality of religion does not cause significant problems because the public has a high degree of tolerance among family members, which is demonstrated through mutual respect and attitude not to interfere in religious affairs of others, and mutual help among family members to facilitate the worship activities of their relatives

    Critical analysis of the Bennett-Riedel attack on secure cryptographic key distributions via the Kirchhoff-law-Johnson-noise scheme

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    Recently, Bennett and Riedel (BR) (http://arxiv.org/abs/1303.7435v1) argued that thermodynamics is not essential in the Kirchhoff-law–Johnson-noise (KLJN) classical physical cryptographic exchange method in an effort to disprove the security of the KLJN scheme. They attempted to demonstrate this by introducing a dissipation-free deterministic key exchange method with two batteries and two switches. In the present paper, we first show that BR's scheme is unphysical and that some elements of its assumptions violate basic protocols of secure communication. All our analyses are based on a technically unlimited Eve with infinitely accurate and fast measurements limited only by the laws of physics and statistics. For non-ideal situations and at active (invasive) attacks, the uncertainly principle between measurement duration and statistical errors makes it impossible for Eve to extract the key regardless of the accuracy or speed of her measurements. To show that thermodynamics and noise are essential for the security, we crack the BR system with 100% success via passive attacks, in ten different ways, and demonstrate that the same cracking methods do not function for the KLJN scheme that employs Johnson noise to provide security underpinned by the Second Law of Thermodynamics. We also present a critical analysis of some other claims by BR; for example, we prove that their equations for describing zero security do not apply to the KLJN scheme. Finally we give mathematical security proofs for each BR-attack against the KLJN scheme and conclude that the information theoretic (unconditional) security of the KLJN method has not been successfully challenged.Laszlo B. Kish, Derek Abbott, Claes G. Granqvis

    Severe stress switches CRF action in the nucleus accumbens from appetitive to aversive.

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    Stressors motivate an array of adaptive responses ranging from \u27fight or flight\u27 to an internal urgency signal facilitating long-term goals. However, traumatic or chronic uncontrollable stress promotes the onset of major depressive disorder, in which acute stressors lose their motivational properties and are perceived as insurmountable impediments. Consequently, stress-induced depression is a debilitating human condition characterized by an affective shift from engagement of the environment to withdrawal. An emerging neurobiological substrate of depression and associated pathology is the nucleus accumbens, a region with the capacity to mediate a diverse range of stress responses by interfacing limbic, cognitive and motor circuitry. Here we report that corticotropin-releasing factor (CRF), a neuropeptide released in response to acute stressors and other arousing environmental stimuli, acts in the nucleus accumbens of naive mice to increase dopamine release through coactivation of the receptors CRFR1 and CRFR2. Remarkably, severe-stress exposure completely abolished this effect without recovery for at least 90 days. This loss of CRF\u27s capacity to regulate dopamine release in the nucleus accumbens is accompanied by a switch in the reaction to CRF from appetitive to aversive, indicating a diametric change in the emotional response to acute stressors. Thus, the current findings offer a biological substrate for the switch in affect which is central to stress-induced depressive disorders
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