1,118 research outputs found

    Interventions to Reduce the Effects of NICU Noise in Preterm Neonates

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    Exposure to excessive noise during a neonates stay in the neonatal intensive care unit (NICU) can create both immediate and long term health problems such as, hearing loss, neurological deficits, and sleep pattern disturbances. The use of earmuffs or earplugs to decrease the neonate’s exposure to noise can create a more stable environment to facilitate improved growth and development. The purpose of this research was to examine the use of earmuffs or earplugs to reduce the impact of noise on neonates. A systematic review of literature was conducted using online databases including CINAHL, ERIC, Ebsco Host, Medline, and PsychINFO. The search included a combination of the following terms: ‘preterm’, ‘neonate’, ‘NICU’, ‘noise’, ‘earplugs’, and ‘earmuffs’. Peer reviewed, articles published in the English language were examined that tested noise reduction devices in the NICU setting, hearing screening of neonates, and the effect of noise reduction interventions on physiologic changes in the preterm infant receiving care in the NICU. Results yielded 8 articles between the years of 1995 to 2017 which were synthesized for review. The results indicated that the use of earmuffs or earplugs in the NICU may offer a viable solution to reducing the effects of excessive noise on neonate’s growth and development. The use of earmuffs or earplugs has been shown to positively improve vital signs, increase growth, improve physiological and motor development, and improve sleep efficiency. Further research on larger sample sizes is needed in order to validate the findings and offer substantial evidence for its use in the clinical setting

    Suppression of Grasshopper Population Numbers with Biologically Effective Grazing Management

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    Research comparing intensity of grasshopper infestations on grasslands with traditional grazing and twice over rotational grazing. Increased vegetation cover from rotational grazing reduces grasshopper numbers as improved grassland habitat is unfavorable for these pests

    Renormalization of the elementary excitations in hole- and electron-doped cuprates due to spin fluctuations

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    Extending our previous studies we present results for the doping-, momentum-, frequency-, and temperature- dependence of the kink-like change of the quasiparticle velocity resulting from the coupling to spin fluctuations. In the nodal direction a kink is found in both the normal and superconducting state while in the antinodal direction a kink occurs only below TcT_c due to the opening of the superconducting gap. A pronounced kink is obtained only for hole-doped, but not for electron-doped cuprates and is characteristically different from what is expected due to electron-phonon interaction. We further demonstrate that the kink structure is intimately connected to the resonance peak seen in inelastic neutron scattering. Our results suggest similar effects in other unconventional superconductors like Sr2RuO4{Sr}_2{RuO}_4.Comment: revised version, 12 pages, 19 figures. accepted for publication in PR

    Melt Production and Ejection From Lunar Intermediate-Sized Impact Craters: Where Is the Molten Material Deposited?

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    Differently aged impact melt in lunar samples is key to unveiling the early bombardment history of the Moon. Due to the mixing of melt products ejected from distant craters, the interpretations of the origin of lunar samples are difficult. We use numerical modeling for a better quantitative understanding of the production of impact-induced melt and in particular its distribution in ejecta blankets for lunar craters with sizes ranging from 1.5 to 50 km. We approximate the lunar stratigraphy with a porosity gradient, which represents the gradual transition from upper regolith via megaregolith to the solid crustal material. For this lunar setting, we quantify the melt production relative to crater volume and derive parameters describing its increasing trend with increasing transient crater size. We found that about 30%–40% of the produced melt is ejected from the crater. The melt concentration in the ejecta blanket increases almost linearly with distance from the crater center, while the thickness of the ejecta blanket decreases following a power law. Our study demonstrates that if in lunar samples the concentration of a melt with a certain age is interpreted to be of a nonlocal origin, these melts could be the impact products of a large crater (>10 km) located hundreds of kilometers away

    Dispersion and damping of zone-boundary magnons in the noncentrosymmetric superconductor CePt3Si

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    Inelastic neutron scattering (INS) is employed to study damped spin-wave excitations in the noncentrosymmetric heavy-fermion superconductor CePt3Si along the antiferromagnetic Brillouin-zone boundary in the low-temperature magnetically ordered state. Measurements along the (1/2 1/2 L) and (H H 1/2-H) reciprocal-space directions reveal deviations in the spin-wave dispersion from the previously reported model. Broad asymmetric shape of the peaks in energy signifies strong spin-wave damping by interactions with the particle-hole continuum. Their energy width exhibits no evident anomalies as a function of momentum along the (1/2 1/2 L) direction, which could be attributed to Fermi-surface nesting effects, implying the absence of pronounced commensurate nesting vectors at the magnetic zone boundary. In agreement with a previous study, we find no signatures of the superconducting transition in the magnetic excitation spectrum, such as a magnetic resonant mode or a superconducting spin gap, either at the magnetic ordering wavevector (0 0 1/2) or at the zone boundary. However, the low superconducting transition temperature in this material still leaves the possibility of such features being weak and therefore hidden below the incoherent background at energies ~0.1 meV, precluding their detection by INS

    Electronic and phononic Raman scattering in detwinned YBa2_2Cu3_3O6.95_{6.95} and Y0.85_{0.85}Ca0.15_{0.15}Ba2_2Cu3_3O6.95_{6.95}: s-wave admixture to the dx2y2d_{x^2-y^2}-wave order parameter

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    Inelastic light (Raman) scattering has been used to study electronic excitations and phonon anomalies in detwinned, slightly overdoped YBa2_2Cu3_3O6.95_{6.95} and moderately overdoped Y0.85_{0.85}Ca0.15_{0.15}Ba2_2Cu3_3O6.95_{6.95} single crystals. In both samples modifications of the electronic pair-breaking peaks when interchanging the a- and b-axis were observed. The lineshapes of several phonon modes involving plane and apical oxygen vibrations exhibit pronounced anisotropies with respect to the incident and scattered light field configurations. Based on a theoretical model that takes both electronic and phononic contributions to the Raman spectra into account, we attribute the anisotropy of the superconductivity-induced changes in the phonon lineshapes to a small s-wave admixture to the dx2y2d_{x^2-y^2} pair wave-function. Our theory allows us to disentangle the electronic Raman signal from the phononic part and to identify corresponding interference terms. We argue that the Raman spectra are consistent with an s-wave admixture with an upper limit of 20 percent.Comment: accepted in Phys. Rev. B, 11 page

    The Anomalous Infrared Emission of Abell 58

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    We present a new model to explain the excess in mid and near infrared emission of the central, hydrogen poor dust knot in the planetary nebula (PN) Abell 58. Current models disagree with ISO measurement because they apply an average grain size and equilibrium conditions only. We investigate grain size distributions and temperature fluctuations affecting infrared emission using a new radiative transfer code and discuss in detail the conditions requiring an extension of the classical description. The peculiar infrared emission of V605 Aql, the central dust knot in Abell 58, has been modeled with our code. V605 Aql is of special interest as it is one of only three stars ever observed to move from the evolutionary track of a central PN star back to the post-AGB state.Comment: 17 pages, 4 figures; accepted and to be published in Ap

    Whole genome sequencing of Plasmodium falciparum from dried blood spots using selective whole genome amplification

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    BACKGROUND: Translating genomic technologies into healthcare applications for the malaria parasite Plasmodium falciparum has been limited by the technical and logistical difficulties of obtaining high quality clinical samples from the field. Sampling by dried blood spot (DBS) finger-pricks can be performed safely and efficiently with minimal resource and storage requirements compared with venous blood (VB). Here, the use of selective whole genome amplification (sWGA) to sequence the P. falciparum genome from clinical DBS samples was evaluated, and the results compared with current methods that use leucodepleted VB. METHODS: Parasite DNA with high (>95%) human DNA contamination was selectively amplified by Phi29 polymerase using short oligonucleotide probes of 8-12 mers as primers. These primers were selected on the basis of their differential frequency of binding the desired (P. falciparum DNA) and contaminating (human) genomes. RESULTS: Using sWGA method, clinical samples from 156 malaria patients, including 120 paired samples for head-to-head comparison of DBS and leucodepleted VB were sequenced. Greater than 18-fold enrichment of P. falciparum DNA was achieved from DBS extracts. The parasitaemia threshold to achieve >5× coverage for 50% of the genome was 0.03% (40 parasites per 200 white blood cells). Over 99% SNP concordance between VB and DBS samples was achieved after excluding missing calls. CONCLUSION: The sWGA methods described here provide a reliable and scalable way of generating P. falciparum genome sequence data from DBS samples. The current data indicate that it will be possible to get good quality sequence on most if not all drug resistance loci from the majority of symptomatic malaria patients. This technique overcomes a major limiting factor in P. falciparum genome sequencing from field samples, and paves the way for large-scale epidemiological applications

    New class of T-prime-structure cuprate superconductors

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    High-temperature superconductivity has been discovered in La2-xBaxCuO4 [1], a compound that derives from the undoped La2CuO4 crystallizing in the perovskite T-structure. In this structure oxygen octahedra surround the copper ions. It is common knowledge that charge carriers induced by doping in such an undoped antiferromagnetic Mott-insulator lead to high-temperature superconductivity [2- 4]. The undoped material La2CuO4 is also the basis of the electron-doped cuprate superconductors [5] of the form La2-xCexCuO4+y [6,7] which however crystallize in the so called T-prime-structure, i.e. without apical oxygen above or below the copper ions of the CuO2-plane. It is well known that for La2-xCexCuO4+y the undoped T-prime-structure parent compound cannot be prepared due to the structural phase transition back into the T-structure occuring around x ~ 0.05. Here, we report that if La is substituted by RE = Y, Lu, Sm, Eu, Gd, or Tb, which have smaller ionic radii but have the same valence as La, nominally undoped La2-xRExCuO4 can be synthesized by molecular beam epitaxy in the T-prime-structure. The second important result is that all these new T-prime-compounds are superconductors with fairly high critical temperatures up to 21 K. For this new class of cuprates La2-xRExCuO4, which forms the T-prime-parent compounds of the La-based electron doped cuprates, we have not been able to obtain the Mott-insulating ground state for small x before the structural phase transition into the T-structure takes place.Comment: 17 pages, 7 figure

    Theory for phonon-induced superconductivity in MgB2_2

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    We analyze superonductivity in MgB2_2 observed below Tc=39T_c=39 K resulting from electron-phonon coupling involving a mode at ω1=24\hbar \omega_1 = 24 meV and most importantly the in-plane B-B E2gE_{2g} vibration at ω2=67\hbar \omega_2=67 meV. The quasiparticles originating from π\pi- and σ\sigma-states couple strongly to the low-frequency mode and the E2gE_{2g}-vibrations respectively. Using two-band Eliashberg theory, λπ=1.4\lambda_{\pi} = 1.4 and λσ=0.7\lambda_{\sigma} = 0.7, we calculate the gap functions Δi(ω,0)\Delta^{i}(\omega,0) (i=πi=\pi, σ\sigma). Our results provide an explanation of recent tunneling experiments. We get Hc2ab/Hc2c3.9H^{ab}_{c_2}/H^{c}_{c_2} \approx 3.9.Comment: revised version, accepted for publication in PR
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