1,239 research outputs found

    The Information Of The Milky Way From 2MASS Whole Sky Star Count: The Bimodal Color Distributions

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    The J-Ks color distribution (CD) with a bin size of 0.05 magnitude for the entire Milky Way has been carried out by using the Two Micron All Sky Survey Point Source Catalog (2MASS PSC). The CDs are bimodal, which has a red peak at 0.8 < J-Ks < 0.85 and a blue peak at 0.3 < J-Ks < 0.4. The colors of the red peak are more or less the same for the whole sky, but that of the blue peak depend on Galactic latitude, (J-Ks ~ 0.35 at low Galactic latitudes and 0.35 < J-Ks < 0.4 for other sky areas). The blue peak dominates the bimodal CDs at low Galactic latitudes and becomes comparable with the red peak in other sky regions. In order to explain the bimodal distribution and the global trend shown by the all sky 2MASS CDs, we assemble an empirical HR diagram, which is composed by observational-based near infrared HR diagrams and color magnitude diagrams, and incorporate a Milky Way model. In the empirical HR diagram, the main sequence stars turnoff the thin disk is relatively bluer, (J-Ks)0 = 0.31, when we compare with the thick disk which is (J-Ks)0 = 0.39. The age of the thin/thick disk is roughly estimated to be around 4-5/8-9 Gyr according to the color-age relation of the main sequence turnoff. In general, the 2MASS CDs can be treated as a tool to census the age of stellar population of the Milky Way in a statistical manner and to our knowledge this is a first attempt to measure the age.Comment: Accepted by ApJ on Sept. 11 201

    Do Gender and Gender Role Orientation Make a Difference in the Link between Role Demands and Family Interference with Work for Taiwanese Workers?

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    From MDPI via Jisc Publications RouterHistory: accepted 2021-09-13, pub-electronic 2021-09-17Publication status: PublishedFunder: Ministry of Science and Technology, Taiwan; Grant(s): MOST106-2410-H-262-005-SSS, MOST108-2410-H-002-126-SS3Based on the gender role orientation perspective, this study extends the resource depletion mechanism that links role demands to family interference with work by testing the moderating effects of gender and gender role orientation (egalitarian vs. traditional) on the relationships. Analysis of the data from 251 employees in Taiwan revealed two significant three-way interactive effects. Specifically, for men, the positive relationship between work demands and family-to-work conflict (FWC) was stronger for egalitarian than traditional individuals. For women, the positive relationship between family demands and FWC was stronger for egalitarian than traditional individuals. We also found a significant two-way interactive effect; that is, within the egalitarian group, the positive relationship between work demands and FWC was stronger for women than men. Our findings, thus, suggest both within-gender and between-gender variations in the links between work-to-family demands and conflict, jointly affected by the individual’s gender and gender role orientation. Contextualized within the cultural traditions of a Chinese society, we highlight the precarious position that egalitarian men and women (especially women) find for themselves in fulfilling work duties and family roles. The theoretical and managerial implications are also discussed

    Experimental and Numerical Study of Tsunami Wave Propagation and Run-Up on Sloping Beaches

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    Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

    Asteroid Spin-Rate Study using the Intermediate Palomar Transient Factory

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    Two dedicated asteroid rotation-period surveys have been carried out using data taken on January 6-9 and February 20-23 of 2014 by the Intermediate Palomar Transient Factory (iPTF) in the RR~band with ∼20\sim 20-min cadence. The total survey area covered 174~deg2^2 in the ecliptic plane. Reliable rotation periods for 1,438 asteroids are obtained from a larger data set of 6,551 mostly main-belt asteroids, each with ≥10\geq 10~detections. Analysis of 1751, PTF based, reliable rotation periods clearly shows the "spin barrier" at ∼2\sim 2~hours for "rubble-pile" asteroids. We also found a new large-sized super-fast rotator, 2005 UW163 (Chang et al., 2014), and other five candidates as well. Our spin-rate distributions of asteroids with 3<D<153 < D < 15~km shows number decrease when frequency greater than 5 rev/day, which is consistent to that of the Asteroid Light Curve Database (LCDB, Warner et al., 2009) and the result of (Masiero et al., 2009). We found the discrepancy in the spin-rate distribution between our result and (Pravec et al., 2008, update 2014-04-20) is mainly from asteroids with Δm<0.2\Delta m < 0.2 mag that might be primarily due to different survey strategies. For asteroids with D≤3D \leq 3~km, we found a significant number drop at f=6f = 6 rev/day. The YORP effect timescale for small-sized asteroid is shorter that makes more elongate objets spun up to reach their spin-rate limit and results in break-up. The K-S test suggests a possible difference in the spin-rate distributions of C- and S-type asteroids. We also find that C-type asteroids have a smaller spin-rate limit than the S-type, which agrees with the general sense that the C-type has lower bulk density than the S-type.Comment: Submitted to ApJ (Jan, 2015). Accepted by ApJ (June, 2015). The whole set of the folded lightcurves will be available on the published articl

    Surface scattering mechanisms of tantalum nitride thin film resistor

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    In this letter, we utilize an electrical analysis method to develop a TaN thin film resistor with a stricter spec and near-zero temperature coefficient of resistance (TCR) for car-used electronic applications. Simultaneously, we also propose a physical mechanism mode to explain the origin of near-zero TCR for the TaN thin film resistor (TFR). Through current fitting, the carrier conduction mechanism of the TaN TFR changes from hopping to surface scattering and finally to ohmic conduction for different TaN TFRs with different TaN microstructures. Experimental data of current–voltage measurement under successive increasing temperature confirm the conduction mechanism transition. A model of TaN grain boundary isolation ability is eventually proposed to influence the carrier transport in the TaN thin film resistor, which causes different current conduction mechanisms

    Causal Evidence for the Role of Specific GABAergic Interneuron Types in Entorhinal Recruitment of Dentate Granule Cells

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    The dentate gyrus (DG) is the primary gate of the hippocampus and controls information flow from the cortex to the hippocampus proper. To maintain normal function, granule cells (GCs), the principal neurons in the DG, receive fine- tuned inhibition from local-circuit GABAergic inhibitory interneurons (INs). Abnormalities of GABAergic circuits in the DG are associated with several brain disorders, including epilepsy, autism, schizophrenia, and Alzheimer disease. Therefore, understanding the network mechanisms of inhibitory control of GCs is of functional and pathophysiological importance. GABAergic inhibitory INs are heterogeneous, but it is unclear how individual subtypes contribute to GC activity. Using cell-type-specific optogenetic perturbation, we investigated whether and how two major IN populations defined by parvalbumin (PV) and somatostatin (SST) expression, regulate GC input transformations. We showed that PV-expressing (PV+) INs, and not SST- expressing (SST+) INs, primarily suppress GC responses to single cortical stimulation. In addition, these two IN classes differentially regulate GC responses to θ and γ frequency inputs from the cortex. Notably, PV+ INs specifically control the onset of the spike series, whereas SST+ INs preferentially regulate the later spikes in the series. Together, PV+ and SST+ GABAergic INs engage differentially in GC input-output transformations in response to various activity patterns

    313 new asteroid rotation periods from Palomar Transient Factory observations

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    A new asteroid rotation period survey have been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg2^2 in the ecliptic plane, were observed in RR band with a cadence of ∼\sim20 min during February 15--18, 2013. We detected 2500 known asteroids with a diameter range of 0.5 km ≤D≤\leq D \leq 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the "spin barrier" at ∼2\sim2 hours. In contrast to the flat spin rate distribution of the asteroids with 3 km ≤D≤\leq D \leq 15 km shown by Pravec et al. (2008), our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev/day. One super-fast-rotator candidate and two possible binary asteroids were also found in this work.Comment: 18 pages, 20 figures and 2 very long table

    The Palomar Transient Factory and RR Lyrae: The Metallicity–Light Curve Relation Based on ab-type RR Lyrae in the Kepler Field

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    The wide-field synoptic sky surveys, known as the Palomar Transient Factory (PTF) and the intermediate Palomar Transient Factory (iPTF), will accumulate a large number of known and new RR Lyrae. These RR Lyrae are good tracers to study the substructure of the Galactic halo if their distance, metallicity, and galactocentric velocity can be measured. Candidates of halo RR Lyrae can be identified from their distance and metallicity before requesting spectroscopic observations for confirmation. This is because both quantities can be obtained via their photometric light curves, because the absolute V-band magnitude for RR Lyrae is correlated with metallicity, and the metallicity can be estimated using a metallicity–light curve relation. To fully utilize the PTF and iPTF light-curve data in related future work, it is necessary to derive the metallicity–light curve relation in the native PTF/iPTF R-band photometric system. In this work, we derived such a relation using the known ab-type RR Lyrae located in the Kepler field, and it is found to be [Fe/H]_(PTF) = -4.089-7.346P + 1.280φ_(31) (where P is pulsational period and φ_(31) is one of the Fourier parameters describing the shape of the light curve), with a dispersion of 0.118 dex. We tested our metallicity–light curve relation with new spectroscopic observations of a few RR Lyrae in the Kepler field, as well as several data sets available in the literature. Our tests demonstrated that the derived metallicity–light curve relation could be used to estimate metallicities for the majority of the RR Lyrae, which are in agreement with the published values
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