5,889 research outputs found

    Analysing delays between time course gene expression data and biomarkers

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    Associating time course gene expression data to biomarkers can help to understand disease progression or response to therapy. However, detecting associations between these expression profiles is not a trivial task. Often expression changes occur not simultaneously but delayed in time and common used methods to detect correlation will fail to identify these associations. We have developed an efficient approach, DynOmics, based on Fast Fourier Transform to identify coordinated response dynamics between time course 'omics' experiments and specific biomarkers of interest while taking time shift into account. We applied DynOmics to a rat study investigating molecular response dynamics to different dosages of acetaminophen ('paracetamol'). We show how DynOmics can extract relevant molecule expression profiles that enables a better understanding of the molecular pathways related to acetaminophen toxic dosage and renal damage

    Equilibrium states of the pressure function for products of matrices

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    Let {Mi}i=1\{M_i\}_{i=1}^\ell be a non-trivial family of d×dd\times d complex matrices, in the sense that for any nNn\in \N, there exists i1...in{1,...,}ni_1... i_n\in \{1,..., \ell\}^n such that Mi1...Min0M_{i_1}... M_{i_n}\neq {\bf 0}. Let P ⁣:(0,)RP \colon (0,\infty)\to \R be the pressure function of {Mi}i=1\{M_i\}_{i=1}^\ell. We show that for each q>0q>0, there are at most dd ergodic qq-equilibrium states of PP, and each of them satisfies certain Gibbs property.Comment: 12 pages. To appear in DCD

    Tunneling dynamics in exactly-solvable models with triple-well potentials

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    Inspired by new trends in atomtronics, cold atoms devices and Bose-Einstein condensate dynamics, we apply a general technique of N=4 extended Supersymmetric Quantum Mechanics to isospectral Hamiltonians with triple-well potentials, i.e. symmetric and asymmetric. Expressions of quantum-mechanical propagators, which take into account all states of the spectrum, are obtained, within the N = 4 SQM approach, in the closed form. For the initial Hamiltonian of a harmonic oscillator, we obtain the explicit expressions of potentials, wavefunctions and propagators. The obtained results are applied to tunneling dynamics of localized states in triple-well potentials and for studying its features. In particular, we observe a Josephson-type tunneling transition of a wave packet, the effect of its partial trapping and a non-monotonic dependence of tunneling dynamics on the shape of a three-well potential. We investigate, among others, the possibility of controlling tunneling transport by changing parameters of the central well, and we briefly discuss potential applications of this aspect to atomtronic devices.Comment: Latex, 28 pages, 7 Figs, 2 Tables; minor presentation changes, journal versio

    Quantum anti-Zeno effect without wave function reduction

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    We study the measurement-induced enhancement of the spontaneous decay (called quantum anti-Zeno effect) for a two-level subsystem, where measurements are treated as couplings between the excited state and an auxiliary state rather than the von Neumann's wave function reduction. The photon radiated in a fast decay of the atom, from the auxiliary state to the excited state, triggers a quasi-measurement, as opposed to a projection measurement. Our use of the term "quasi-measurement" refers to a "coupling-based measurement". Such frequent quasi-measurements result in an exponential decay of the survival probability of atomic initial state with a photon emission following each quasi-measurement. Our calculations show that the effective decay rate is of the same form as the one based on projection measurements. What is more important, the survival probability of the atomic initial state which is obtained by tracing over all the photon states is equivalent to the survival probability of the atomic initial state with a photon emission following each quasi-measurement to the order under consideration. That is because the contributions from those states with photon number less than the number of quasi-measurements originate from higher-order processes.Comment: 7 pages, 3 figure

    A microstructure model for viscoelastic–thixotropic fluids

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    A microstructure model to describe the viscoelasticity and thixotropy properties of complex fluids is proposed. The model is based on the Lodge–Yamamoto network theory and is an extension of the Phan-Thien–Tanner model, with a kinetic process in which specific forms of creation and destruction rates are assumed. The final equation is simple with a small number of empirical parameters required and can be conveniently employed in engineering simulations. The predictions based on the model in a variety of shear and oscillatory shear flows are given. The stress response obtained from the model prediction agrees well with experiments on both shear and oscillatory flow histories

    Long-lived charged Higgs at LHC as a probe of scalar Dark Matter

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    We study inert charged Higgs boson H±H^\pm production and decays at LHC experiments in the context of constrained scalar dark matter model (CSDMM). In the CSDMM the inert doublet and singlet scalar's mass spectrum is predicted from the GUT scale initial conditions via RGE evolution. We compute the cross sections of processes ppH+H,H±Si0pp\to H^+H^-,\, H^\pm S_i^0 at the LHC and show that for light H±H^\pm the first one is dominated by top quark mediated 1-loop diagram with Higgs boson in s-channel. In a significant fraction of the parameter space H±H^\pm are long-lived because their decays to predominantly singlet scalar dark matter (DM) and next-to-lightest (NL) scalar, H±SDM, NLff,H^\pm\to S_{\text{DM, NL}} ff', are suppressed by the small singlet-doublet mixing angle and by the moderate mass difference ΔM=MH+MDM. \Delta M=M_{H^+}-M_{\text{DM}} . The experimentally measurable displaced vertex in H±H^\pm decays to leptons and/or jets and missing energy allows one to discover the H+HH^+H^- signal over the huge W+WW^+W^- background. We propose benchmark points for studies of this scenario at the LHC. If, however, H±H^\pm are short-lived, the subsequent decays SNLSDMffˉS_{\text{NL}}\to S_{\text{DM}} f\bar f necessarily produce additional displaced vertices that allow to reconstruct the full H±H^\pm decay chain.Comment: 15 pages, 5 figure

    The Maximal U(1)LU(1)_L Inverse Seesaw from d=5d=5 Operator and Oscillating Asymmetric Sneutrino Dark Matter

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    The maximal U(1)LU(1)_L supersymmetric inverse seesaw mechanism (MLLSIS) provides a natural way to relate asymmetric dark matter (ADM) with neutrino physics. In this paper we point out that, MLLSIS is a natural outcome if one dynamically realizes the inverse seesaw mechanism in the next-to minimal supersymmetric standard model (NMSSM) via the dimension-five operator (N)2S2/M(N)^2S^2/M_*, with SS the NMSSM singlet developing TeV scale VEV; it slightly violates lepton number due to the suppression by the fundamental scale MM_*, thus preserving U(1)LU(1)_L maximally. The resulting sneutrino is a distinguishable ADM candidate, oscillating and favored to have weak scale mass. A fairly large annihilating cross section of such a heavy ADM is available due to the presence of singlet.Comment: journal versio

    The STAFF-DWP wave instrument on the DSP equatorial spacecraft: description and first results

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    The STAFF-DWP wave instrument on board the equatorial spacecraft (TC1) of the Double Star Project consists of a combination of 2 instruments which are a heritage of the Cluster mission: the Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment and the Digital Wave-Processing experiment (DWP). On DSP-TC1 STAFF consists of a three-axis search coil magnetometer, used to measure magnetic fluctuations at frequencies up to 4 kHz and a waveform unit, up to 10 Hz, plus snapshots up to 180 Hz. DWP provides several onboard analysis tools: a complex FFT to fully characterise electromagnetic waves in the frequency range 10 Hz-4 kHz, a particle correlator linked to the PEACE electron experiment, and compression of the STAFF waveform data. The complementary Cluster and TC1 orbits, together with the similarity of the instruments, permits new multi-point studies. The first results show the capabilities of the experiment, with examples in the different regions of the magnetosphere-solar wind system that have been encountered by DSP-TC1 at the beginning of its operational phase. An overview of the different kinds of electromagnetic waves observed on the dayside from perigee to apogee is given, including the different whistler mode waves (hiss, chorus, lion roars) and broad-band ULF emissions. The polarisation and propagation characteristics of intense waves in the vicinity of a bow shock crossing are analysed using the dedicated PRASSADCO tool, giving results compatible with previous studies: the broad-band ULF waves consist of a superimposition of different wave modes, whereas the magnetosheath lion roars are right-handed and propagate close to the magnetic field. An example of a combined Cluster DSP-TC1 magnetopause crossing is given. This first case study shows that the ULF wave power intensity is higher at low latitude (DSP) than at high latitude (Cluster). On the nightside in the tail, a first wave event comparison - in a rather quiet time interval - is shown. It opens the doors to future studies, such as event timing during substorms, to possibly determine their onset location

    Evaluation of serum glycoprotein biomarker candidates for detection of esophageal adenocarcinoma and surveillance of Barrett’s esophagus

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    Esophageal adenocarcinoma (EAC) is thought to develop from asymptomatic Barrett’s esophagus (BE) with a low annual rate of conversion. Current endoscopy surveillance for BE patients is probably not cost-effective. Previously, we discovered serum glycoprotein biomarker candidates which could discriminate BE patients from EAC. Here, we aimed to validate candidate serum glycoprotein biomarkers in independent cohorts, and to develop a biomarker candidate panel for BE surveillance. Serum glycoprotein biomarker candidates were measured in 301 serum samples collected from Australia (4 states) and USA (1 clinic) using previously established lectin magnetic bead array (LeMBA) coupled multiple reaction monitoring mass spectrometry (MRM-MS) tier 3 assay. The area under receiver operating characteristic curve (AUROC) was calculated as a measure of discrimination, and multivariate recursive partitioning was used to formulate a multimarker panel for BE surveillance. Complement C9 (C9), gelsolin (GSN), serum paraoxonase/arylesterase 1 (PON1) and serum paraoxonase/lactonase 3 (PON3) were validated as diagnostic glycoprotein biomarkers in lectin pull-down samples for EAC across both cohorts. A panel of 10 serum glycoprotein biomarker candidates discriminated BE patients not requiring intervention [BE+/- low grade dysplasia] from those requiring intervention [BE with high grade dysplasia (BE-HGD) or EAC] with an AUROC value of 0.93. Tissue expression of C9 was found to be induced in BE, dysplastic BE and EAC. In longitudinal samples from subjects that have progressed towards EAC, levels of serum C9 were significantly (P\u3c0.05) increased with disease progression in EPHA (erythroagglutinin from Phaseolus vulgaris) and NPL (Narcissus pseudonarcissus lectin) pull-down samples. The results confirm alteration of complement pathway glycoproteins during BE-EAC pathogenesis. Further prospective clinical validation of the confirmed biomarker candidates in a large cohort is warranted, prior to development of a first-line BE surveillance blood test
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