607 research outputs found

    Simplified amino acid alphabets based on deviation of conditional probability from random background

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    The primitive data for deducing the Miyazawa-Jernigan contact energy or BLOSUM score matrix consists of pair frequency counts. Each amino acid corresponds to a conditional probability distribution. Based on the deviation of such conditional probability from random background, a scheme for reduction of amino acid alphabet is proposed. It is observed that evident discrepancy exists between reduced alphabets obtained from raw data of the Miyazawa-Jernigan's and BLOSUM's residue pair counts. Taking homologous sequence database SCOP40 as a test set, we detect homology with the obtained coarse-grained substitution matrices. It is verified that the reduced alphabets obtained well preserve information contained in the original 20-letter alphabet.Comment: 9 pages,3figure

    Decrease in Incidence of Young-Onset Colorectal Cancer Before Recent Increase

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    The increasing incidence of colorectal cancer in younger adults (aged <50 years) has been widely reported. Using data from the Surveillance, Epidemiology, and End Results Program, we found young-onset colorectal cancer incidence rates decreased from 1975 through about 1990. Decreases were more prominent in the colon, a contrast with more recent increases in rectal cancer. Incidence rates subsequently increased, differing by time period and 5-year age group. This inflection point is consistent with a birth cohort effect and points to early life exposures—accumulated throughout the life course—that may increase cancer risk. Studying early life exposures among persons born after 1960 may advance our understanding of colorectal cancer in younger adults

    Curvature in causal BD-type inflationary cosmology

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    We study a closed model of the universe filled with viscous fluid and quintessence matter components in a Brans-Dicke type cosmological model. The dynamical equations imply that the universe may look like an accelerated flat Friedmann-Robertson-Walker universe at low redshift. We consider here dissipative processes which follow a causal thermodynamics. The theory is applied to viscous fluid inflation, where accepted values for the total entropy in the observable universe is obtained.Comment: 11 pages, revtex 4. For a festschrift honoring Alberto Garcia. To be publishen in Gen. Rel. Gra

    Targeted nasal vaccination provides antibody-independent protection against Staphylococcus aureus.

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    Despite showing promise in preclinical models, anti-Staphylococcus aureus vaccines have failed in clinical trials. To date, approaches have focused on neutralizing/opsonizing antibodies; however, vaccines exclusively inducing cellular immunity have not been studied to formally test whether a cellular-only response can protect against infection. We demonstrate that nasal vaccination with targeted nanoparticles loaded with Staphylococcus aureus antigen protects against acute systemic S. aureus infection in the absence of any antigen-specific antibodies. These findings can help inform future developments in staphylococcal vaccine development and studies into the requirements for protective immunity against S. aureus

    Assessing reproducibility for radiographic measurement of leg length inequality after total hip replacement

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    Leg length inequality (LLI) as a result of total hip replacement can cause considerable morbidity. Although LLI was described when the technique was popularised in the 1960s, it remains a significant challenge to arthroplasty surgeons. This study reviews the established practice for the measurement of LLI on plain antero-posterior radiograph, and compares these techniques to two methods used locally. The radiographs of 35 patients were measured using four techniques. All four methods yielded an interclass correlation co-efficient of ≥0.90 for inter reader reliability. This study shows that the four methods are comparable for reliability, while a composite method, measuring from the centre of femoral rotation to the inferior teardrop and then to the lesser trochanter, has the added advantage of providing extra information on component position as well as an overall measure of LLI

    5-HT<sub>4</sub> Receptor Agonist Effects on Functional Connectivity in the Human Brain:Implications for Procognitive Action

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    Background: Cognitive deficits are often comorbid with mood disorders and can cause significant functional impairment even after resolution of the primary mood symptoms. We do not currently have pharmacological treatments that adequately address these deficits. 5-HT4 receptor agonists show promise as potential procognitive agents in animal and early human translational studies. Optimal cognitive performance in humans is directly associated with appropriate functional connectivity between specific resting-state neural networks. However, so far the effect of 5-HT4 receptor agonism on resting-state functional connectivity (rsFC) in the brain in humans is unknown.Methods: We collected resting-state functional magnetic resonance imaging scans from 50 healthy volunteers, of whom 25 received 6 days × 1 mg prucalopride (a highly selective 5-HT4 receptor agonist) and 25 received placebo in a randomized double-blind design.Results: Network analyses identified that participants in the prucalopride group had enhanced rsFC between the central executive network and the posterior/anterior cingulate cortex. Seed analyses also showed greater rsFC between the left and right rostral anterior cingulate cortex and the left lateral occipital cortex, and reduced rsFC between the hippocampus and other default mode network regions.Conclusions: Similar to other potentially procognitive medications, low-dose prucalopride in healthy volunteers appeared to enhance rsFC between regions involved in cognitive networks and reduce rsFC within the default mode network. This suggests a mechanism for the behavioral cognitive enhancement previously seen with 5-HT4 receptor agonists in humans and supports the potential for 5-HT4 receptor agonists to be used in clinical psychiatric populations

    Can the Pioneer anomaly be of gravitational origin? A phenomenological answer

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    In order to satisfy the equivalence principle, any non-conventional mechanism proposed to gravitationally explain the Pioneer anomaly, in the form in which it is presently known from the so-far analyzed Pioneer 10/11 data, cannot leave out of consideration its impact on the motion of the planets of the Solar System as well, especially those orbiting in the regions in which the anomalous behavior of the Pioneer probes manifested itself. In this paper we, first, discuss the residuals of the right ascension \alpha and declination \delta of Uranus, Neptune and Pluto obtained by processing various data sets with different, well established dynamical theories (JPL DE, IAA EPM, VSOP). Second, we use the latest determinations of the perihelion secular advances of some planets in order to put on the test two gravitational mechanisms recently proposed to accommodate the Pioneer anomaly based on two models of modified gravity. Finally, we adopt the ranging data to Voyager 2 when it encountered Uranus and Neptune to perform a further, independent test of the hypothesis that a Pioneer-like acceleration can also affect the motion of the outer planets of the Solar System. The obtained answers are negative.Comment: Latex2e, 26 pages, 6 tables, 2 figure, 47 references. It is the merging of gr-qc/0608127, gr-qc/0608068, gr-qc/0608101 and gr-qc/0611081. Final version to appear in Foundations of Physic

    Scenario of Accelerating Universe from the Phenomenological \Lambda- Models

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    Dark matter, the major component of the matter content of the Universe, played a significant role at early stages during structure formation. But at present the Universe is dark energy dominated as well as accelerating. Here, the presence of dark energy has been established by including a time-dependent Λ\Lambda term in the Einstein's field equations. This model is compatible with the idea of an accelerating Universe so far as the value of the deceleration parameter is concerned. Possibility of a change in sign of the deceleration parameter is also discussed. The impact of considering the speed of light as variable in the field equations has also been investigated by using a well known time-dependent Λ\Lambda model.Comment: Latex, 9 pages, Major change

    A finite element approach for the acoustic modelling of perforated dissipative mufflers with non-homogeneous properties

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    [EN] In this work, a finite element approach is presented for modeling sound propagation in perforated dissipative mufflers with non-homogeneous properties. The spatial variations of the acoustic properties can arise, for example, from uneven filling processes during manufacture and degradation associated with the flow of soot particles within the absorbent material. First, the finite element method is applied to the wave equation for a propagation medium with variable properties (outer chamber with absorbent material) and a homogeneous medium (central passage). For the case of a dissipative muffler, the characterization of the absorbent material is carried out by means of its equivalent complex density and speed of sound. To account for the spatial variations of these properties, a coordinate-dependent function is proposed for the filling density of the absorbent material. The coupling between the outer chamber and the central passage is achieved by using the acoustic impedance of the perforated central pipe, that relates the acoustic pressure jump and the normal velocity through the perforations. The acoustic impedance of the perforated central duct includes the influence of the absorbent material and therefore a spatial variation of the impedance is also taken into account. A detailed study is then presented to assess the influence of the heterogeneous properties and the perforated duct porosity on the acoustic attenuation performance of the muffler.The authors gratefully acknowledge the financial support of Ministerio de Ciencia e Innovacion and the European Regional Development Fund by means of the projects DPI2007-62635 and DPI2010-15412.Antebas, A.; Denia Guzmán, FD.; Pedrosa Sanchez, AM.; Fuenmayor Fernández, FJ. (2013). A finite element approach for the acoustic modelling of perforated dissipative mufflers with non-homogeneous properties. Mathematical and Computer Modelling. 57(7):1970-1978. https://doi.org/10.1016/j.mcm.2012.01.021S1970197857

    Rip/singularity free cosmology models with bulk viscosity

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    In this paper we present two concrete models of non-perfect fluid with bulk viscosity to interpret the observed cosmic accelerating expansion phenomena, avoiding the introduction of exotic dark energy. The first model we inspect has a viscosity of the form ζ=ζ0+(ζ1ζ2q)H{\zeta} = {\zeta}_0 + ({\zeta}_1-{\zeta}_2q)H by taking into account of the decelerating parameter q, and the other model is of the form ζ=ζ0+ζ1H+ζ2H2{\zeta} = {\zeta}_0 + {\zeta}_1H + {\zeta}_2H^2. We give out the exact solutions of such models and further constrain them with the latest Union2 data as well as the currently observed Hubble-parameter dataset (OHD), then we discuss the fate of universe evolution in these models, which confronts neither future singularity nor little/pseudo rip. From the resulting curves by best fittings we find a much more flexible evolution processing due to the presence of viscosity while being consistent with the observational data in the region of data fitting. With the bulk viscosity considered, a more realistic universe scenario is characterized comparable with the {\Lambda}CDM model but without introducing the mysterious dark energy.Comment: 9 pages, 6 figures, submitted to EPJ-
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