119 research outputs found

    Distortion in Perspective Projection

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    The paper presents a unique approach in associating perspective projection with the image beheld by the eye and demonstrates that all graphical and photographic perspective projections must contain distortion when compared to the image beheld by the eye

    Phandango: an interactive viewer for bacterial population genomics.

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    Summary: Fully exploiting the wealth of data in current bacterial population genomics datasets requires synthesising and integrating different types of analysis across millions of base pairs in hundreds or thousands of isolates. Current approaches often use static representations of phylogenetic, epidemiological, statistical and evolutionary analysis results that are difficult to relate to one another. Phandango is an interactive application running in a web browser allowing fast exploration of large-scale population genomics datasets combining the output from multiple genomic analysis methods in an intuitive and interactive manner. Availability: Phandango is a web application freely available for use at www.phandango.net and includes a diverse collection of datasets as examples. Source code together with a detailed wiki page is available on GitHub at https://github.com/jameshadfield/phandango. Contact: [email protected], [email protected]

    The Virtual Teacher (VT) Paradigm: Learning New Patterns of Interpersonal Coordination Using the Human Dynamic Clamp

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    The Virtual Teacher paradigm, a version of the Human Dynamic Clamp (HDC), is introduced into studies of learning patterns of inter-personal coordination. Combining mathematical modeling and experimentation, we investigate how the HDC may be used as a Virtual Teacher (VT) to help humans co-produce and internalize new inter-personal coordination pattern(s). Human learners produced rhythmic finger movements whilst observing a computer-driven avatar, animated by dynamic equations stemming from the well-established Haken-Kelso-Bunz (1985) and Schöner-Kelso (1988) models of coordination. We demonstrate that the VT is successful in shifting the pattern co-produced by the VT-human system toward any value (Experiment 1) and that the VT can help humans learn unstable relative phasing patterns (Experiment 2). Using transfer entropy, we find that information flow from one partner to the other increases when VT-human coordination loses stability. This suggests that variable joint performance may actually facilitate interaction, and in the long run learning. VT appears to be a promising tool for exploring basic learning processes involved in social interaction, unraveling the dynamics of information flow between interacting partners, and providing possible rehabilitation opportunities

    Multiphysics simulation of a microfluidic perfusion chamber for brain slice physiology

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    Understanding and optimizing fluid flows through in vitro microfluidic perfusion systems is essential in mimicking in vivo conditions for biological research. In a previous study a microfluidic brain slice device (μBSD) was developed for microscale electrophysiology investigations. The device consisted of a standard perfusion chamber bonded to a polydimethylsiloxane (PDMS) microchannel substrate. Our objective in this study is to characterize the flows through the μBSD by using multiphysics simulations of injections into a pourous matrix to identify optimal spacing of ports. Three-dimensional computational fluid dynamic (CFD) simulations are performed with CFD-ACE + software to model, simulate, and assess the transport of soluble factors through the perfusion bath, the microchannels, and a material that mimics the porosity, permeability and tortuosity of brain tissue. Additionally, experimental soluble factor transport through a brain slice is predicted by and compared to simulated fluid flow in a volume that represents a porous matrix material. The computational results are validated with fluorescent dye experiments

    The Repertoire of Heterotrimeric G Proteins and RGS Proteins in Ciona intestinalis

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    BACKGROUND:Heterotrimeric G proteins and regulators of G protein signaling (RGS) proteins are key downstream interacting partners in the G protein coupled receptor (GPCR) signaling pathway. The highly versatile GPCR transmembrane signaling system is a consequence of the coupling of a diverse set of receptors to downstream partners that include multiple subforms of G proteins and regulatory proteins including RGS proteins, among others. While the GPCR repertoire of Ciona intestinalis, representing the basal chordate is known, the repertoire of the heterotrimeric G proteins and RGS proteins is unknown. METHODOLOGY/PRINCIPAL FINDINGS:In the present study, we performed an in-silico genome-wide search of C. intestinalis for its complement of G proteins and RGS proteins. The identification of several one-to-one orthologs of human G proteins at the levels of families, subfamilies and types and of homologs of the human RGS proteins suggests an evolutionarily conserved structure function relationship of the GPCR signaling mechanism in the chordates. CONCLUSIONS:The C. intestinalis genome encodes a highly conserved, albeit, limited repertoire of the heterotrimeric G protein complexes with the size of subunit types comparable with that in lower eukaryotes

    The effect of the “rod-and-frame” illusion on grip planning in a sequential object manipulation task

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    We investigated the effect of visual context (i.e., a visual illusion) on the planning of a sequential object manipulation task. Participants (n = 13) had to grasp a rod embedded in a “rod-and-frame” illusion and insert the rod-end into a tight hole in a pre-defined way. The grip type (defined by start posture, either pronated or supinated; and end posture, either comfortable or uncomfortable) used to grasp the rod was registered as a macroscopic variable of motor planning. Different rod orientations forced the participants to switch between grip types. As expected, most participants switched between pronated and supinated start postures, such that they ended the movement with a comfortable end posture. As it has been argued that planning is dependent on visual context information, we hypothesized that the visual illusion would affect the specific rod orientation at which participants would switch into a different grip type. This hypothesis was confirmed. More specifically, the illusion affected the critical spatial information that is used for action planning. Collectively, these findings are the first to show an effect of an illusion on motor planning in a sequential object manipulation task

    Phenomenology of Light Sneutrino Dark Matter in cMSSM/mSUGRA with Inverse Seesaw

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    We study the possibility of a light Dark Matter (DM) within a constrained Minimal Supersymmetric Standard Model (cMSSM) framework augmented by a SM singlet-pair sector to account for the non-zero neutrino masses by inverse seesaw mechanism. Working within a 'hybrid' scenario with the MSSM sector fixed at high scale and the singlet neutrino sector at low scale, we find that, contrary to the case of the usual cMSSM where the neutralino DM cannot be very light, we can have a light sneutrino DM with mass below 100 GeV satisfying all the current experimental constraints from cosmology, collider as well as low-energy experiments. We also note that the supersymmetric inverse seesaw mechanism with sneutrino as the lightest supersymmetric partner can have enhanced same-sign dilepton final states with large missing transverse energy (mET) coming from the gluino- and squark-pair as well as the squark-gluino associated productions and their cascade decay through charginos. We present a collider study for the same-sign dilepton+jets+mET signal in this scenario and propose some distinctions with the usual cMSSM. We also comment on the implications of such a light DM scenario on the invisible decay width of an 125 GeV Higgs boson.Comment: 24 pages, 4 figures, 7 tables; matches published versio

    The anti-vaccination movement and resistance to allergen-immunotherapy: a guide for clinical allergists

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    Despite over a century of clinical use and a well-documented record of efficacy and safety, a growing minority in society questions the validity of vaccination and fear that this common public health intervention is the root-cause of severe health problems. This article questions whether growing public anti-vaccine sentiments might have the potential to spill-over into other therapies distinct from vaccination, namely allergen-immunotherapy. Allergen-immunotherapy shares certain medical vernacular with vaccination (e.g., allergy shots, allergy vaccines), and thus may become "guilty by association" due to these similarities. Indeed, this article demonstrates that anti-vaccine websites have begun unduly discrediting this allergy treatment regimen. Following an explanation of the anti-vaccine movement, the article aims to provide guidance on how clinicians can respond to patient fears towards allergen-immunotherapy in the clinical setting. This guide focuses on the provision of reliable information to patients in order to dispel misconceived associations between vaccination and allergen-immunotherapy, and the discussion of the risks and benefits of both therapies in order to assist patients in making autonomous decisions about their choice of allergy treatment

    Snapshot of the Eukaryotic Gene Expression in Muskoxen Rumen—A Metatranscriptomic Approach

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    BACKGROUND: Herbivores rely on digestive tract lignocellulolytic microorganisms, including bacteria, fungi and protozoa, to derive energy and carbon from plant cell wall polysaccharides. Culture independent metagenomic studies have been used to reveal the genetic content of the bacterial species within gut microbiomes. However, the nature of the genes encoded by eukaryotic protozoa and fungi within these environments has not been explored using metagenomic or metatranscriptomic approaches. METHODOLOGY/PRINCIPAL FINDINGS: In this study, a metatranscriptomic approach was used to investigate the functional diversity of the eukaryotic microorganisms within the rumen of muskoxen (Ovibos moschatus), with a focus on plant cell wall degrading enzymes. Polyadenylated RNA (mRNA) was sequenced on the Illumina Genome Analyzer II system and 2.8 gigabases of sequences were obtained and 59129 contigs assembled. Plant cell wall degrading enzyme modules including glycoside hydrolases, carbohydrate esterases and polysaccharide lyases were identified from over 2500 contigs. These included a number of glycoside hydrolase family 6 (GH6), GH48 and swollenin modules, which have rarely been described in previous gut metagenomic studies. CONCLUSIONS/SIGNIFICANCE: The muskoxen rumen metatranscriptome demonstrates a much higher percentage of cellulase enzyme discovery and an 8.7x higher rate of total carbohydrate active enzyme discovery per gigabase of sequence than previous rumen metagenomes. This study provides a snapshot of eukaryotic gene expression in the muskoxen rumen, and identifies a number of candidate genes coding for potentially valuable lignocellulolytic enzymes

    CART Peptide Is a Potential Endogenous Antioxidant and Preferentially Localized in Mitochondria

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    The multifunctional neuropeptide Cocaine and Amphetamine Regulated Transcript (CART) is secreted from hypothalamus, pituitary, adrenal gland and pancreas. It also can be found in circulatory system. This feature suggests a general role for CART in different cells. In the present study, we demonstrate that CART protects mitochondrial DNA (mtDNA), cellular proteins and lipids against the oxidative action of hydrogen peroxide, a widely used oxidant. Using cis-parinaric acid as a sensitive reporting probe for peroxidation in membranes, and a lipid-soluble azo initiator of peroxyl radicals, 2,2′-Azobis(2,4-dimethylvaleronitrile) we found that CART is an antioxidant. Furthermore, we found that CART localized to mitochondria in cultured cells and mouse brain neuronal cells. More importantly, pretreatment with CART by systemic injection protects against a mouse oxidative stress model, which mimics the main features of Parkinson's disease. Given the unique molecular structure and biological features of CART, we conclude that CART is an antioxidant peptide (or antioxidant hormone). We further propose that it may have strong therapeutic properties for human diseases in which oxidative stress is strongly involved such as Parkinson's disease
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