58,945 research outputs found

    On-line analysis of random vibrations

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    Measuring device, Randomdec, provides continuous on-line signatures representative of system free vibration curve. Selected points on curve are used in control and failure detection systems. Apparatus applied to both linear and nonlinear systems under nonstationary vibratory states

    Perception of Patient Cooperation Among Dentist, Guardian, and Child

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    Purpose: Evaluate behavior assessment and agreement among dentist, guardian, and child. Evaluate child behavior by appointment type. Methods: Patients recruited from the pediatric dental department at Virginia Commonwealth University for this convenience sample. Inclusion criteria: patients presenting for clinical exams and/or restorative treatment without the use of advanced behavior guidance between August 29, 2018, and March 7, 2019; ages 4-12-years-old; and scheduled with a single clinician. Appointments were stratified by difficulty. Behavior was assessed by dentist and caregiver using the Frankl Scale. Patient self-assessed cooperation using an age-appropriate modified Frankl Scale, developed for this study. Agreement assessed among the 3 scores at each appointment using descriptive statistics and Cohen’s Kappa. Behavior trends across appointment type assessed using Kruskal-Wallis test. SAS software (2013, Cary, NC). P-value \u3c 0.05. Results: Forty-one patient-guardian dyads enrolled in the study. Five dyads experienced multiple encounters. Demographics for the patients enrolled: 59% male; 44% Caucasian, 29% African American, 5% Asian, 2% Hispanic, 20% other/multiracial. Average patient age: 7.6 (range: 4- 12). Most patients had 1 encounter (n=36, 88%). Frankl Score agreement for provider/guardian was 79% (k=0.335), provider/child was 70% (k=0.248), and guardian/child was 81% (k=0.314). In disagreements, guardians rated behavior better than provider. Disagreement was split for provider/child and guardian/child, with the child tending to rate themselves higher, and the guardian tending to rate the child higher respectively. Marginal evidence that hard appointments resulted in poorer behaviors. Conclusion: There is fair agreement between child, guardian, and provider. In disagreements, guardians tend to rate the child’s behavior better compared to the provider and child self-assessment. Dental providers tend to be more critical of patient behavior. Marginal evidence to support harder appointments result in poorer behaviors

    Financial Development, Bank Ownership, and Growth. Or, Does Quantity Imply Quality?

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    In 1980, India nationalized its large private banks. This induced different bank ownership patterns across different towns, allowing credible identification of the effects of bank ownership on financial development, lending rates, and the quality of intermediation, as well as employment and investment. Credit markets with nationalized banks experienced faster credit growth during a period of financial repression. Nationalization led to lower interest rates and lower quality intermediation, and may have slowed employment gains in trade and services. Development lending goals were met, but these had no impact on the real economy.

    The star formation history of the Sculptor Dwarf Irregular Galaxy

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    [abridged] We study the resolved stellar populations and derive the SFH of the SDIG, a gas-rich dwarf galaxy member of the NGC7793 subgroup in the Sculptor group. We construct a CMD using archival HST observations and examine its stellar content. We derive its SFH using a maximum-likelihood fit to the CMD. The CMD shows that SDIG contains stars from 10Myr to several Gyr old, as revealed from the MS, BL, luminous AGB, and RGB stars. The young stars with ages less than ~250Myr show a spatial distribution confined to its central regions, and additionally the young MS stars exhibit an off-center density peak. The intermediate-age and older stars are more spatially extended. SDIG is dominated by intermediate-age stars with an average age of 6.4Gyr. The average metallicity inferred is [M/H]\approx -1.5dex. Its SFH is consistent with a constant SFR, except for ages younger than ~200Myr. The lifetime average SFR is 1.3x10^{-3} Mo/yr. More recently than 100Myr, there has been a burst of SF at a rate ~2-3 times higher than the average SFR. The inferred recent SFR from CMD modelling is higher than inferred from the Ha flux of the galaxy; we interpret this to mean that the upper end of the IMF is not being fully sampled due to the low SFR. Additionally, an observed lack of bright blue stars in the CMD could indicate a downturn in SFR on 10^7-yr timescales. A previous SF enhancement appears to have occurred between 600-1100Myr ago, with amplitude similar to the most recent 100Myr. Older bursts of similar peak SFR and duration would not be resolvable with these data. The observed enhancements in SF suggest that SDIG is able to sustain a complex SFH without the effect of interactions with its nearest massive galaxy. Integrating the SFR over the entire history of SDIG yields a total stellar mass 1.77x10^{7}Mo, and a current V-band stellar mass-to-light ratio 3.2Mo/Lo.Comment: A&A accepted; 10 pages, 9 figure

    Red Giants in the Small Magellanic Cloud. II. Metallicity Gradient and Age-Metallicity Relation

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    We present results from the largest CaII triplet line metallicity study of Small Magellanic Cloud (SMC) field red giant stars to date, involving 3037 objects spread across approximately 37.5 sq. deg., centred on this galaxy. We find a median metallicity of [Fe/H]=-0.99+/-0.01, with clear evidence for an abundance gradient of -0.075+/-0.011 dex / deg. over the inner 5 deg. We interpret the abundance gradient to be the result of an increasing fraction of young stars with decreasing galacto-centric radius, coupled with a uniform global age-metallicity relation. We also demonstrate that the age-metallicity relation for an intermediate age population located 10kpc in front of the NE of the Cloud is indistinguishable from that of the main body of the galaxy, supporting a prior conjecture that this is a stellar analogue of the Magellanic Bridge. The metal poor and metal rich quartiles of our RGB star sample (with complementary optical photometry from the Magellanic Clouds Photometric Survey) are predominantly older and younger than approximately 6Gyr, respectively. Consequently, we draw a link between a kinematical signature, tentatively associated by us with a disk-like structure, and the upsurges in stellar genesis imprinted on the star formation history of the central regions of the SMC. We conclude that the increase in the star formation rate around 5-6Gyr ago was most likely triggered by an interaction between the SMC and LMC.Comment: To appear in MNRA

    Red Giants in the Small Magellanic Cloud. I. Disk and Tidal Stream Kinematics

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    We present results from an extensive spectroscopic survey of field stars in the Small Magellanic Cloud (SMC). 3037 sources, predominantly first-ascent red giants, spread across roughly 37.5 sq. deg, are analysed. The line of sight velocity field is dominated by the projection of the orbital motion of the SMC around the LMC/Milky Way. The residuals are inconsistent with both a non-rotating spheroid and a nearly face on disk system. The current sample and previous stellar and HI kinematics can be reconciled by rotating disk models with line of nodes position angle, theta, ~ 120-130 deg., moderate inclination (i ~ 25-70 deg.), and rotation curves rising at 20-40 km/s/kpc. The metal-poor stars exhibit a lower velocity gradient and higher velocity dispersion than the metal-rich stars. If our interpretation of the velocity patterns as bulk rotation is appropriate, then some revision to simulations of the SMC orbit is required since these are generally tuned to the SMC disk line-of-nodes lying in a NE-SW direction. Residuals show strong spatial structure indicative of non-circular motions that increase in importance with increasing distance from the SMC centre. Kinematic substructure in the north-west part of our survey area is associated with the tidal tail or Counter-Bridge predicted by simulations. Lower line-of-sight velocities towards the Wing and the larger velocities just beyond the SW end of the SMC Bar are probably associated with stellar components of the Magellanic Bridge and Counter-Bridge, respectively. Our results reinforce the notion that the intermediate-age stellar population of the SMC is subject to substantial stripping by external forces.Comment: To appear in MNRA
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