575 research outputs found

    Comparative Network Analysis of Preterm vs. Full-Term Infant-Mother Interactions

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    Several studies have reported that interactions of mothers with preterm infants show differential characteristics compared to that of mothers with full-term infants. Interaction of preterm dyads is often reported as less harmonious. However, observations and explanations concerning the underlying mechanisms are inconsistent. In this work 30 preterm and 42 full-term mother-infant dyads were observed at one year of age. Free play interactions were videotaped and coded using a micro-analytic coding system. The video records were coded at one second resolution and studied by a novel approach using network analysis tools. The advantage of our approach is that it reveals the patterns of behavioral transitions in the interactions. We found that the most frequent behavioral transitions are the same in the two groups. However, we have identified several high and lower frequency transitions which occur significantly more often in the preterm or full-term group. Our analysis also suggests that the variability of behavioral transitions is significantly higher in the preterm group. This higher variability is mostly resulted from the diversity of transitions involving non-harmonious behaviors. We have identified a maladaptive pattern in the maternal behavior in the preterm group, involving intrusiveness and disengagement. Application of the approach reported in this paper to longitudinal data could elucidate whether these maladaptive maternal behavioral changes place the infant at risk for later emotional, cognitive and behavioral disturbance

    The role of parental achievement goals in predicting autonomy-supportive and controlling parenting

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    Although autonomy-supportive and controlling parenting are linked to numerous positive and negative child outcomes respectively, fewer studies have focused on their determinants. Drawing on achievement goal theory and self-determination theory, we propose that parental achievement goals (i.e., achievement goals that parents have for their children) can be mastery, performance-approach or performance-avoidance oriented and that types of goals predict mothers' tendency to adopt autonomy-supportive and controlling behaviors. A total of 67 mothers (aged 30-53 years) reported their goals for their adolescent (aged 13-16 years; 19.4 % girls), while their adolescent evaluated their mothers' behaviors. Hierarchical regression analyses showed that parental performance-approach goals predict more controlling parenting and prevent acknowledgement of feelings, one autonomy-supportive behavior. In addition, mothers who have mastery goals and who endorse performance-avoidance goals are less likely to use guilt-inducing criticisms. These findings were observed while controlling for the effect of maternal anxiety

    Guillain-Barré syndrome: a century of progress

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    In 1916, Guillain, Barré and Strohl reported on two cases of acute flaccid paralysis with high cerebrospinal fluid protein levels and normal cell counts — novel findings that identified the disease we now know as Guillain–Barré syndrome (GBS). 100 years on, we have made great progress with the clinical and pathological characterization of GBS. Early clinicopathological and animal studies indicated that GBS was an immune-mediated demyelinating disorder, and that severe GBS could result in secondary axonal injury; the current treatments of plasma exchange and intravenous immunoglobulin, which were developed in the 1980s, are based on this premise. Subsequent work has, however, shown that primary axonal injury can be the underlying disease. The association of Campylobacter jejuni strains has led to confirmation that anti-ganglioside antibodies are pathogenic and that axonal GBS involves an antibody and complement-mediated disruption of nodes of Ranvier, neuromuscular junctions and other neuronal and glial membranes. Now, ongoing clinical trials of the complement inhibitor eculizumab are the first targeted immunotherapy in GBS

    Twelve years' detection of respiratory viruses by immunofluorescence in hospitalised children: impact of the introduction of a new respiratory picornavirus assay

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    <p>Abstract</p> <p>Background</p> <p>Direct immunofluorescence assays (DFA) are a rapid and inexpensive method for the detection of respiratory viruses and may therefore be used for surveillance. Few epidemiological studies have been published based solely on DFA and none included respiratory picornaviruses and human metapneumovirus (hMPV). We wished to evaluate the use of DFA for epidemiological studies with a long-term observation of respiratory viruses that includes both respiratory picornaviruses and hMPV.</p> <p>Methods</p> <p>Since 1998 all children hospitalized with respiratory illness at the University Hospital Bern have been screened with DFA for common respiratory viruses including adenovirus, respiratory syncytial virus (RSV), influenza A and B, and parainfluenza virus 1-3. In 2006 assays for respiratory picornaviruses and hMPV were added. Here we describe the epidemiological pattern for these respiratory viruses detected by DFA in 10'629 nasopharyngeal aspirates collected from 8'285 patients during a 12-year period (1998-2010).</p> <p>Results</p> <p>Addition of assays for respiratory picornaviruses and hMPV raised the proportion of positive DFA results from 35% to 58% (p < 0.0001). Respiratory picornaviruses were the most common viruses detected among patients ≥1 year old. The seasonal patterns and age distribution for the studied viruses agreed well with those reported in the literature. In 2010, an hMPV epidemic of unexpected size was observed.</p> <p>Conclusions</p> <p>DFA is a valid, rapid, flexible and inexpensive method. The addition of assays for respiratory picornaviruses and hMPV broadens its range of viral detection. DFA is, even in the "PCR era", a particularly adapted method for the long term surveillance of respiratory viruses in a pediatric population.</p

    Centrality and transverse momentum dependence of elliptic flow of multi-strange hadrons and ϕ\phi meson in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

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    We present high precision measurements of elliptic flow near midrapidity (y<1.0|y|<1.0) for multi-strange hadrons and ϕ\phi meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy sNN=\sqrt{s_{NN}}= 200 GeV. We observe that the transverse momentum dependence of ϕ\phi and Ω\Omega v2v_{2} is similar to that of π\pi and pp, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0-30%\% and 30-80%\% collision centrality. There is an indication of the breakdown of previously observed mass ordering between ϕ\phi and proton v2v_{2} at low transverse momentum in the 0-30%\% centrality range, possibly indicating late hadronic interactions affecting the proton v2v_{2}.Comment: 7 pages and 4 figures, Accepted for publication in Physical Review Letter

    Energy dependence of acceptance-corrected dielectron excess mass spectrum at mid-rapidity in Au+Au collisions at sNN=19.6\sqrt{s_{NN}} = 19.6 and 200 GeV

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    The acceptance-corrected dielectron excess mass spectra, where the known hadronic sources have been subtracted from the inclusive dielectron mass spectra, are reported for the first time at mid-rapidity yee<1|y_{ee}|<1 in minimum-bias Au+Au collisions at sNN\sqrt{s_{NN}} = 19.6 and 200 GeV. The excess mass spectra are consistently described by a model calculation with a broadened ρ\rho spectral function for Mee<1.1M_{ee}<1.1 GeV/c2c^{2}. The integrated dielectron excess yield at sNN\sqrt{s_{NN}} = 19.6 GeV for 0.4<Mee<0.750.4<M_{ee}<0.75 GeV/c2c^2, normalized to the charged particle multiplicity at mid-rapidity, has a value similar to that in In+In collisions at sNN\sqrt{s_{NN}} = 17.3 GeV. For sNN\sqrt{s_{NN}} = 200 GeV, the normalized excess yield in central collisions is higher than that at sNN\sqrt{s_{NN}} = 17.3 GeV and increases from peripheral to central collisions. These measurements indicate that the lifetime of the hot, dense medium created in central Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV is longer than those in peripheral collisions and at lower energies.Comment: 9 pages, 6 figure

    Isolation of Flow and Nonflow Correlations by Two- and Four-Particle Cumulant Measurements of Azimuthal Harmonics in sNN=\sqrt{s_{_{\rm NN}}} = 200 GeV Au+Au Collisions

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    A data-driven method was applied to measurements of Au+Au collisions at sNN=\sqrt{s_{_{\rm NN}}} = 200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance Δη\Delta\eta-dependent and Δη\Delta\eta-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a component of the correlation that is Δη\Delta\eta-independent, which is likely dominated by anisotropic flow and flow fluctuations. It was also found to be independent of η\eta within the measured range of pseudorapidity η<1|\eta|<1. The relative flow fluctuation was found to be 34%±2%(stat.)±3%(sys.)34\% \pm 2\% (stat.) \pm 3\% (sys.) for particles of transverse momentum pTp_{T} less than 22 GeV/cc. The Δη\Delta\eta-dependent part may be attributed to nonflow correlations, and is found to be 5%±2%(sys.)5\% \pm 2\% (sys.) relative to the flow of the measured second harmonic cumulant at Δη>0.7|\Delta\eta| > 0.7

    Elliptic flow of electrons from heavy-flavor hadron decays in Au+Au collisions at sNN=\sqrt{s_{\rm NN}} = 200, 62.4, and 39 GeV

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    We present measurements of elliptic flow (v2v_2) of electrons from the decays of heavy-flavor hadrons (eHFe_{HF}) by the STAR experiment. For Au+Au collisions at sNN=\sqrt{s_{\rm NN}} = 200 GeV we report v2v_2, for transverse momentum (pTp_T) between 0.2 and 7 GeV/c using three methods: the event plane method (v2v_{2}{EP}), two-particle correlations (v2v_2{2}), and four-particle correlations (v2v_2{4}). For Au+Au collisions at sNN\sqrt{s_{\rm NN}} = 62.4 and 39 GeV we report v2v_2{2} for pT<2p_T< 2 GeV/c. v2v_2{2} and v2v_2{4} are non-zero at low and intermediate pTp_T at 200 GeV, and v2v_2{2} is consistent with zero at low pTp_T at other energies. The v2v_2{2} at the two lower beam energies is systematically lower than at sNN=\sqrt{s_{\rm NN}} = 200 GeV for pT<1p_T < 1 GeV/c. This difference may suggest that charm quarks interact less strongly with the surrounding nuclear matter at those two lower energies compared to sNN=200\sqrt{s_{\rm NN}} = 200 GeV.Comment: Version accepted by PR

    Beam energy dependent two-pion interferometry and the freeze-out eccentricity of pions in heavy ion collisions at STAR

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    We present results of analyses of two-pion interferometry in Au+Au collisions at sNN\sqrt{s_{NN}} = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV measured in the STAR detector as part of the RHIC Beam Energy Scan program. The extracted correlation lengths (HBT radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mTm_{T}) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.Comment: 27 pages; 27 figure
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