214 research outputs found

    Stability of an oscillating tip in Non-Contact Atomic Force Microscopy: theoretical and numerical investigations

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    This paper is a theoretical and a numerical investigation of the stability of a tip-cantilever system used in Non-Contact Atomic Force Microscopy (NC-AFM) when it oscillates close to a surface. No additional dissipative force is considered. The theoretical approach is based on a variationnal method exploiting a coarse grained operation that gives the temporal dependence of the nonlinear coupled equations of motion in amplitude and phase of the oscillator. Stability criterions for the resonance peak are deduced and predict a stable behavior of the oscillator in the vicinity of the resonance. The numerical approach is based on results obtained with a virtual NC-AFM developped in our group. The effect of the size of the stable domain in phase is investigated. These results are in particularly good agreement with the theoretical predictions. Also they show the influence of the phase shifter in the feedback loop and the way it can affect the damping signal

    PP270—Computational modeling of dravet syndrome

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    e102 Volume 35 Number 8S clorazepate (20mg 2× /d), and pregabalin (100 mg 3× /d). Because of resurgence of severe anxio-depressive symptoms, without any change of the treatment, the patient was readmitted 2 months later. Despite increasing the dose of clomipramine up to 225 mg/d, there was no clinical improvement, and the patient finally attempted to her life by abusing drugs. She then improved after 2 weeks on clomipramine IV (50 mg/d). Compliance was estimated good and no pharmacokinetic interactions with the rest of the treatment were found. C and DC plasma levels were measured, and CYP2D6/CYP2C19 genotype analyzed. Results: The plasma levels of C and DC are given in the Table below. Measures were done at the steady state and at trough concentration for IV treatment and 10 hours after the last dose for oral treatment

    Influence of noncontact dissipation in the tapping mode: Attempt to extract quantitative information on the surface properties with the local force probe method

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    In the Tapping mode, a variation of the oscillation amplitude and phase as a function of the tip sample distance is the necessary measurement to access quantitatively to the properties of the surface. In the present work, we give a systematic comparison between experimental data recorded on two surfaces, phase and amplitude, and theoretical curves. With an interaction between the tip and the surface taking into account an attractive and a repulsive term, the analytical approach is unable to properly describe the relationship between the phase variation and the oscillation amplitude variation. When an additional dissipation term is involved, due to the attractive interaction between the tip and the surface, the model gives a good agreement with the recorded data. Particularly, the trends in the phase variations related to the noncontact situations have been found to be amenable to an analysis based upon a simple viscoelastic behavior of the surface

    ALMA-IMF IX: Catalog and Physical Properties of 315 SiO Outflow Candidates in 15 Massive Protoclusters

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    We present a catalog of 315 protostellar outflow candidates detected in SiO J=5-4 in the ALMA-IMF Large Program, observed with ~2000 au spatial resolution, 0.339 km/s velocity resolution, and 2-12 mJy/beam (0.18-0.8 K) sensitivity. We find median outflow masses, momenta, and kinetic energies of ~0.3 M⊙_{\odot}, 4 M⊙_{\odot} km/s, and 1045^{45} erg, respectively. Median outflow lifetimes are 6,000 years, yielding median mass, momentum, and energy rates of M˙\dot{M} = 10−4.4^{-4.4} M⊙_{\odot} yr−1^{-1}, P˙\dot{P} = 10−3.2^{-3.2} M⊙_{\odot} km/s yr−1^{-1}, and E˙\dot{E} = 1 L⊙_{\odot}. We analyze these outflow properties in the aggregate in each field. We find correlations between field-aggregated SiO outflow properties and total mass in cores (~3−-5σ\sigma), and no correlations above 3σ\sigma with clump mass, clump luminosity, or clump luminosity-to-mass ratio. We perform a linear regression analysis and find that the correlation between field-aggregated outflow mass and total clump mass - which has been previously described in the literature - may actually be mediated by the relationship between outflow mass and total mass in cores. We also find that the most massive SiO outflow in each field is typically responsible for only 15-30% of the total outflow mass (60% upper limit). Our data agree well with the established mechanical force-bolometric luminosity relationship in the literature, and our data extend this relationship up to L ≄\geq 106^6 L⊙_{\odot} and P˙\dot{P} ≄\geq 1 M⊙_{\odot} km/s yr−1^{-1}. Our lack of correlation with clump L/M is inconsistent with models of protocluster formation in which all protostars start forming at the same time.Comment: 46 pages, 14 figures, 10 tables. This publication has an associated Zenodo entry, which can be found here: https://zenodo.org/records/835059

    Substitution of adeno-associated virus Rep protein binding and nicking sites with human Chromosome 19 sequences

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    <p>Abstract</p> <p>Background</p> <p>Adeno-associated virus type 2 (AAV2) preferentially integrates its DNA at a ~2 kb region of human chromosome 19, designated <it>AAVS1 </it>(also known as <it>MBS85</it>). Integration at <it>AAVS1 </it>requires the AAV2 replication (Rep) proteins and a DNA sequence within <it>AAVS1 </it>containing a 16 bp Rep recognition sequence (RRS) and closely spaced Rep nicking site (also referred to as a terminal resolution site, or <it>trs</it>). The AAV2 genome is flanked by inverted terminal repeats (ITRs). Each ITR contains an RRS and closely spaced <it>trs</it>, but the sequences differ from those in <it>AAVS1</it>. These ITR sequences are required for replication and packaging.</p> <p>Results</p> <p>In this study we demonstrate that the <it>AAVS1 </it>RRS and <it>trs </it>can function in AAV2 replication, packaging and integration by replacing a 61 bp region of the AAV2 ITR with a 49 bp segment of <it>AAVS1 </it>DNA. Modifying one or both ITRs did not have a large effect on the overall virus titers. These modifications did not detectably affect integration at <it>AAVS1</it>, as measured by semi-quantitative nested PCR assays. Sequencing of integration junctions shows the joining of the modified ITRs to <it>AAVS1 </it>sequences.</p> <p>Conclusions</p> <p>The ability of these <it>AAVS1 </it>sequences to substitute for the AAV2 RRS and <it>trs </it>provides indirect evidence that the stable secondary structure encompassing the <it>trs </it>is part of the AAV2 packaging signal.</p

    The Global Risk Approach Should Be Better Applied in French Hypertensive Patients: A Comparison between Simulation and Observation Studies

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    The prediction of the public health impact of a preventive strategy provides valuable support for decision-making. International guidelines for hypertension management have introduced the level of absolute cardiovascular risk in the definition of the treatment target population. The public health impact of implementing such a recommendation has not been measured.We assessed the efficiency of three treatment scenarios according to historical and current versions of practice guidelines on a Realistic Virtual Population representative of the French population aged from 35 to 64 years: 1) BP≄160/95 mm Hg; 2) BP≄140/90 mm Hg and 3) BP≄140/90 mm Hg plus increased CVD risk. We compared the eligibility following the ESC guidelines with the recently observed proportion of treated amongst hypertensive individuals reported by the Etude Nationale Nutrition SantĂ© survey. Lowering the threshold to define hypertension multiplied by 2.5 the number of eligible individuals. Applying the cardiovascular risk rule reduced this number significantly: less than 1/4 of hypertensive women under 55 years and less than 1/3 of hypertensive men below 45 years of age. This was the most efficient strategy. Compared to the simulated guidelines application, men of all ages were undertreated (between 32 and 60%), as were women over 55 years (70%). By contrast, younger women were over-treated (over 200%).The global CVD risk approach to decide for treatment is more efficient than the simple blood pressure level. However, lack of screening rather than guideline application seems to explain the low prescription rates among hypertensive individuals in France. Multidimensional analyses required to obtain these results are possible only through databases at the individual level: realistic virtual populations should become the gold standard for assessing the impact of public health policies at the national level

    ALMA-IMF. VII. First release of the full spectral line cubes: Core kinematics traced by DCN J=(3-2)

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    ALMA-IMF is an Atacama Large Millimeter/submillimeter Array (ALMA) Large Program designed to measure the core mass function (CMF) of 15 protoclusters chosen to span their early evolutionary stages. It further aims to understand their kinematics, chemistry, and the impact of gas inflow, accretion, and dynamics on the CMF. We present here the first release of the ALMA-IMF line data cubes (DR1), produced from the combination of two ALMA 12m-array configurations. The data include 12 spectral windows, with eight at 1.3mm and four at 3mm. The broad spectral coverage of ALMA-IMF (~6.7 GHz bandwidth coverage per field) hosts a wealth of simple atomic, molecular, ionised, and complex organic molecular lines. We describe the line cube calibration done by ALMA and the subsequent calibration and imaging we performed. We discuss our choice of calibration parameters and optimisation of the cleaning parameters, and we demonstrate the utility and necessity of additional processing compared to the ALMA archive pipeline. As a demonstration of the scientific potential of these data, we present a first analysis of the DCN (3-2) line. We find that DCN traces a diversity of morphologies and complex velocity structures, which tend to be more filamentary and widespread in evolved regions and are more compact in the young and intermediate-stage protoclusters. Furthermore, we used the DCN (3-2) emission as a tracer of the gas associated with 595 continuum cores across the 15 protoclusters, providing the first estimates of the core systemic velocities and linewidths within the sample. We find that DCN (3-2) is detected towards a higher percentage of cores in evolved regions than the young and intermediate-stage protoclusters and is likely a more complete tracer of the core population in more evolved protoclusters. The full ALMA 12m-array cubes for the ALMA-IMF Large Program are provided with this DR1 release.Comment: 75 pages (21 main body; 54 appendix), 37 figures. The ALMA-IMF DR1 line release is hosted at https://dataverse.harvard.edu/dataverse/alma-im

    <i>Herschel</i>-HOBYS study of the earliest phases of high-mass star formation in NGC 6357

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    Aims: To constrain models of high-mass star formation it is important to identify the massive dense cores (MDCs) that are able to form high-mass star(s). This is one of the purposes of the Herschel/HOBYS key programme. Here, we carry out the census and characterise of the properties of the MDCs population of the NGC 6357 H II region. Methods: Our study is based on the Herschel/PACS and SPIRE 70−500 ÎŒm images of NGC 6357 complemented with (sub-)millimetre and mid-infrared data. We followed the procedure established by the Herschel/HOBYS consortium to extract ~0.1 pc massive dense cores using the getsources software. We estimated their physical parameters (temperatures, masses, luminosities) from spectral energy distribution (SED) fitting. Results: We obtain a complete census of 23 massive dense cores, amongst which one is found to be IR-quiet and twelve are starless, representing very early stages of the star-formation process. Focussing on the starless MDCs, we have considered their evolutionary status, and suggest that only five of them are likely to form a high-mass star. Conclusions: We find that, contrarily to the case in NGC 6334, the NGC 6357 region does not exhibit any ridge or hub features that are believed to be crucial to the massive star formation process. This study adds support for an empirical model in which massive dense cores and protostars simultaneously accrete mass from the surrounding filaments. In addition, the massive star formation in NGC 6357 seems to have stopped and the hottest stars in Pismis 24 have disrupted the filaments
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