824 research outputs found

    THIRD TIME’S A CHARM? UNIVERSAL DARWINISM AND ITS FASCINATING REACH

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    Why do we like a certain advertisement over another? Is there a fundamental design in the universe thatdictates our lives - the way we talk and walk? The answer is YES. The biological evolution has designed us humans over a period of millions of years through a simple design element called ‘gene’. Similarly, our thoughts, ideas and stories – cultural evolution – explains how we think the way we do – through a simple design element ‘meme’. Universal Darwinism explains how evolutionary processes are constantly working, fighting and competing against one another to make us who we are today. To add to the surprise, all of this works on a simple algorithm. Are we designed by super-intelligence or are we just the products of a mindless evolutionary process that runs on a simple algorithm? Is there a third replicator? All of this can be understood if one can understand a simple algorithm – The Evolutionary Algorithm of Universal Darwinism

    The detection of wound infection by ion mobility chemical analysis

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    Surgical site infection represents a large burden of care in the National Health Service. Current methods for diagnosis include a subjective clinical assessment and wound swab culture that may take several days to return a result. Both techniques are potentially unreliable and result in delays in using targeted antibiotics. Volatile organic compounds (VOCs) are produced by micro-organisms such as those present in an infected wound. This study describes the use of a device to differentiate VOCs produced by an infected wound vs. colonised wound. Malodourous wound dressings were collected from patients, these were a mix of post-operative wounds and vascular leg ulcers. Wound microbiology swabs were taken and antibiotics commenced as clinically appropriate. A control group of soiled, but not malodorous wound dressings were collected from patients who had a split skin graft (SSG) donor site. The analyser used was a G.A.S. GC-IMS. The results from the samples had a sensitivity of 100% and a specificity of 88%, with a positive predictive value of 90%. An area under the curve (AUC) of 91% demonstrates an excellent ability to discriminate those with an infected wound from those without. VOC detection using GC-IMS has the potential to serve as a diagnostic tool for the differentiation of infected and non-infected wounds and facilitate the treatment of wound infections that is cost effective, non-invasive, acceptable to patients, portable, and reliable

    Long-range orbitofrontal and amygdala axons show divergent patterns of maturation in the frontal cortex across adolescence.

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    The adolescent transition from juvenile to adult is marked by anatomical and functional remodeling of brain networks. Currently, the cellular and synaptic level changes underlying the adolescent transition are only coarsely understood. Here, we use two-photon imaging to make time-lapse observations of long-range axons that innervate the frontal cortex in the living brain. We labeled cells in the orbitofrontal cortex (OFC) and basolateral amygdala (BLA) and imaged their axonal afferents to the dorsomedial prefrontal cortex (dmPFC). We also imaged the apical dendrites of dmPFC pyramidal neurons. Images were taken daily in separate cohorts of juvenile (P24-P28) and young adult mice (P64-P68), ages where we have previously discovered differences in dmPFC dependent decision-making. Dendritic spines were pruned across this peri-adolescent period, while BLA and OFC afferents followed alternate developmental trajectories. OFC boutons showed no decrease in density, but did show a decrease in daily bouton gain and loss with age. BLA axons showed an increase in both bouton density and daily bouton gain at the later age, suggesting a delayed window of enhanced plasticity. Our findings reveal projection specific maturation of synaptic structures within a single frontal region and suggest that stabilization is a more general characteristic of maturation than pruning

    Quantification of LPS Eluate from Coated Microelectrode Devices

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    Penetrating microelectrode arrays have a great potential to be used as control and communication interfaces for neuroprosthetics. A persistent obstacle in the clinical implementation of microelectrode arrays is the chronic degradation of these devices, putatively due to the foreign body response. Though researchers have studied the progression of the foreign body response and the effect of anti-inflammatory drugs on the efficacy of the implant, the exact biological mechanisms of implant degradation are not fully understood. To more closely investigate the effect of the foreign body response on device degradation, neuroinflammation can be exacerbated by coating dummy electrodes implanted into mice brains with lipopolysaccharide (LPS) – a cell wall component of bacteria which induces inflammation. Quantifying the amount of LPS released from a coated electrode is crucial in performing such an experiment. Using a Limulus amebocyte lysate (LAL) test – a test based on the extract of the blood from horseshoe crab which reacts with LPS – the concentration of LPS can be accurately quantified, allowing for a more careful characterization of the inflammatory response. In particular, the devices coated in 1 mg/ml concentration of LPS eluted a mean mass of 4.55 EU with a standard deviation of .51, where 1 endotoxin unit (EU) ≈ 1 ng. A linear regression of the standard concentrations resulted in an r2 of .9806, indicating a reliable model for calculating the concentration of LPS present in a sample. These results suggest that LPS elution can be accurately and precisely measured using the LAL assay

    Using Herbicide Programs to Control Weeds in Corn (Zea mays L.) and Cotton (Gossypium hirsutum L.)

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    Field studies were conducted to evaluate control of Amaranthus species and other weeds in corn and cotton. In corn, Palmer amaranth control was at least 90% with preemergence applications of fluthiacet‐methyl plus pyroxasulfone, atrazine plus either acetochlor, alachlor, dimethenamid‐P, S‐metolachlor, or S‐metolachlor plus mesotrione, saflufenacil plus dimethenamid‐P, and S‐metolachlor plus mesotrione. When using postemergence herbicides applied to Palmer amaranth less than 5 cm tall, atrazine, prosulfuron, and topramezone alone or the combinations of atrazine plus S‐metolachlor plus glyphosate, diflufenzopyr plus dicamba, dimethenamid plus glyphosate, halosulfuron‐methyl plus dicamba, mesotrione plus S‐metolachlor plus glyphosate, pyroxasulfone plus glyphosate, and thiencarbazone‐methyl plus tembotrione provided at least 91% control. In cotton, pyrithiobac applied preemergence resulted in no greater than 63% of control of Palmer amaranth and common waterhemp at the early season rating. Pendimethalin applied preemergence provided varied levels of control of common waterhemp. Trifluralin, applied preplant incorporated, consistently provided at least 86% or greater control of both species. A decreased level of control of both Palmer amaranth and common waterhemp was observed with pendimethalin applied preemergence followed by pyrithiobac‐applied early postemergence and followed by glufosinate applied mid‐post. Systems which included an early postemergence and mid‐postemergence application of glyphosate plus 2,4‐d choline provided at least 94% season‐long Palmer amaranth control

    First principles investigation of the electronic structure of La2MnNiO6: A room-temperature insulating ferromagnet

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    Using first principles calculations within DFT based on the full potential APW+lo method, we calculated the electronic and magnetic structures for the ferromagnetic and antiferromagnetic states of La2MnNiO6 and analyzed the site projected density of states and electronic band structures. Our calculations show that the ground state of La2MnNiO6 is ferromagnetic insulating with the magnetization in agreement with Hund's first rule and experimental findings.Comment: 10 pages, 3 figure

    Local moment formation in quantum point contacts

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    Spin-density-functional theory of quantum point contacts (QPCs) reveals the formation of a local moment with a net of one electron spin in the vicinity of the point contact - supporting the recent report of a Kondo effect in a QPC. The hybridization of the local moment to the leads decreases as the QPC becomes longer, while the onsite Coulomb-interaction energy remains almost constant.Comment: 10 pages, 3 figures, accepted for publication in Physical Review Letter

    Histoplasmosis in an immunocompetent host: a rare case report

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    Histoplasmosis, a systemic mycosis caused by Histoplasma capsulatum manifests clinically in immunocompromised patients as acute or chronic pulmonary infection or as a progressive disseminated disease. In immunocompetent hosts, the disease is usually self-limited or presents as flu-like symptoms. It is endemic in North, Central and South America as well as parts of Europe and Africa. We report a case of a 76-year-old diabetic, HIV negative patient who presented with white nodular patches on the tongue and gingiva which were reported as histoplasmosis on histopathology. He also had idiopathic CD4 lymphocytopenia and thrombocytopenia

    Symmetry of the Atomic Electron Density in Hartree, Hartree-Fock, and Density Functional Theory

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    The density of an atom in a state of well-defined angular momentum has a specific finite spherical harmonic content, without and with interactions. Approximate single-particle schemes, such as the Hartree, Hartree-Fock, and Local Density Approximations, generally violate this feature. We analyze, by means of perturbation theory, the degree of this violation and show that it is small. The correct symmetry of the density can be assured by a constrained-search formulation without significantly altering the calculated energies. We compare our procedure to the (different) common practice of spherically averaging the self-consistent potential. Kohn-Sham density functional theory with the exact exchange-correlation potential has the correct finite spherical harmonic content in its density; but the corresponding exact single particle potential and wavefunctions contain an infinite number of spherical harmonics.Comment: 11 pages, 6 figures. Expanded discussion of spherical harmonic expansion of Hartree density. Some typos corrected, references adde
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