35,858 research outputs found
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
A microscopic surface-enhanced Raman study of a single adsorbate-covered colloidal silver aggregate
No full textChildhood adversity is associated with adulthood white blood cell count through narcissism
No full textThe immune system's response to threat is to amass protective white blood cells. We investigated (N = 234) individual differences in white blood cell (WBC) through the lens of life history theory by examining individual differences in (self-reported) childhood threats (i.e., unpredictability and harshness), life history speed, and the Dark Triad traits (i.e., Machiavellianism, narcissism, and psychopathy). People with adverse childhood conditions had faster life history strategies and higher Dark Triad traits, and were more prone to be inflamed (i.e., sexually transmitted infections). In addition, men reported more childhood harshness, Machiavellianism, psychopathy, and a faster life history strategy and a higher WBC count than women did. Moreover, we revealed, through structural equation models, that the effects of childhood adversity on adult WBC count were mediated by narcissism especially in women. Results are discussed in terms of the mechanism underlying the association between childhood environments and physiological health
Relations between x-ray timing features and spectral parameters of galactic black hole x-ray binaries
No full textWe present a study of correlations between spectral and timing parameters for a sample of black hole X-ray binary candidates. Data are taken from GX
339-4, H 1743-322, and XTE J1650-500, as the Rossi X-ray Timing Explorer
(RXTE) observed complete outbursts of these sources. In our study we investigate outbursts that happened before the end of 2009 to make use of the high-energy coverage of the HEXTE detector and select observations that
show a certain type of quasi-periodic oscillations (type-C QPOs). The spectral parameters are derived using the empirical convolution model simpl to model the Comptonized component of the emission together with a disc blackbody for the emission of the accretion disc. Additional spectral features, namely a reflection component, a high-energy cut-off, and excess emission at 6.4 keV, are taken into account. Our investigations confirm the known positive
correlation between photon index and centroid frequency of the QPOs and reveal an anti-correlation between the fraction of up-scattered photons and the QPO frequency. We show that both correlations behave as expected in the “sombrero”
geometry. Furthermore, we find that during outburst decay the correlation between photon index and QPO frequency follow a general track, independent of individual outbursts
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Observation of ψ (3686) →p p φ OBSERVATION of ψ (3686) →p p φ M. ABLIKIM et al
No full textUsing a data sample of 4.48 x 10(8) psi(3686) events collected with the BESIII detector, we present a first observation of psi(3686) -> p (p) over bar phi, and we measure its branching fraction to be [6.06 +/- 0.38(stat)+/- 0.48(syst)] x 10(-6). In contrast to the earlier discovery of a threshold enhancement in the p (p) over bar -mass spectrum of the channel j/psi -> gamma p (p) over bar, denoted as X(p (p) over bar), we do not find a similar enhancement in psi(3686) -> p (p) over bar phi. An upper limit of 1.82 x 10(-7) at the 90% confidence level on the branching fraction of psi(3686) -> X(p (p) over bar)phi -> p (p) over bar phi is obtained
Anomaly Detection—Empirical Approach
No full textIn this chapter, the empirical approach to the problem of anomaly detection is presented, which is free from the pre-defined model and user-and problem-specific parameters and is data driven. The well-known Chebyshev inequality has been simplified by using the standardized eccentricity. An autonomous anomaly detection method is proposed, which is composed of two stages. In the first stage, all the potential global anomalies are selected out based on the data density and/or on the typicality, and in the second stage, the local anomalies are identified based on the data clouds formed from the potential global anomalies. In addition, a fully autonomous approach for the problem of fault detection has been outlined, which can also be extended to a fully autonomous fault detection and isolation approach. © 2019, Springer Nature Switzerland AG
Existence of radial solutions for a p(x) -Laplacian Dirichlet problem
No full textIn this paper, using variational methods, we prove the existence of at least one positive radial solution for the generalized p(x) -Laplacian problem − Δ p(x)u+ R(x) up(x)−2u= a(x) | u| q(x)−2u− b(x) | u| r(x)−2u with Dirichlet boundary condition in the unit ball in RN (for N≥ 3), where a, b, R are radial functions. © 2021, The Author(s)
Two-Dimensional Alloying Molybdenum Tin Disulfide Monolayers with Fast Photoresponse
No full textElemental alloying in monolayer, two-dimensional (2D) transition metal dichalcogenides (TMDs) promises unprecedented ability to modulate their electronic structure leading to unique optoelectronic properties. MoS2 monolayer based photodetectors typically exhibit a high photoresponsivity but suffer from a low response time. Here we develop a new approach for Sn alloying in MoS2 monolayers based on the synergy of the customized chemical vapor deposition (CVD) and the effects of common salt (NaCl) to produce high-quality and large-size Mo1-xSnxS2 (x 0.5) present multilayer grains. The Mo1-xSnxS2 (x < 0.5) based photodetectors and phototransistors exhibit a maximum responsitivity of 12 mA/W and a minimum response time of 20 ms, which is faster than most reported MoS2-based photodetectors. This work offers new perspectives for precision 2D alloy engineering to improve the optoelectronic performance of TMD-based photodetectors.No Full Tex
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Observation of ψ (3686) →p p ̄ η′ and improved measurement of J /ψ →p p ̄ η′ OBSERVATION of ... M. ABLIKIM et al
No full textWe observe the process psi(3686) -> p (p) over bar eta' for the first time, with a statistical significance higher than 10 sigma, and measure the branching fraction of J/psi -> p (p) over bar eta' with an improved accuracy compared to earlier studies. The measurements are based on 4.48 x 10(8) psi(3686) and 1.31 x 10(9) J/psi events collected by the BESIII detector operating at the BEPCII. The branching fractions are determined to be B(psi(3686) -> p (p) over bar eta') = (1.10 +/- 0.10 +/- 0.08) x 10(-5) and B(J/psi -> p (p) over bar eta' = (1.26 +/- 0.02 +/- 0.07) x 10(-4), where the first uncertainties are statistical and the second ones systematic. Additionally, the eta - eta' mixing angle is determined to be -24 degrees +/- 11 degrees based on psi(3686) -> p (p) over bar eta', and -24 degrees +/- 9 degrees based on J/psi -> p (p) over bar eta', respectively
On algebraic surfaces of general type with negative c(2)
No full textWe prove that for any prime number p >= 3, there exists a positive number kappa(p) such that x(O-x) >= kappa C-p(1)2 holds true for all algebraic surfaces X of general type in characteristic p. In particular, x(O-x) > 0. This answers a question of Shepherd-Barron when p >= 3.SCI(E)[email protected]
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