We present new constraints on the dark matter-induced annual modulation signal using 1.7 years of COSINE-100 data with a total exposure of 97.7 kg yr. The COSINE-100 experiment, consisting of 106 kg ...of NaI(Tl) target material, is designed to carry out a model-independent test of DAMA/LIBRA's claim of WIMP discovery by searching for the same annual modulation signal using the same NaI(Tl) target. The crystal data show a 2.7 cpd/kg/keV background rate on average in the 2-6 keV energy region of interest. Using a χ-squared minimization method we observe best fit values for modulation amplitude and phase of 0.0092±0.0067 cpd/kg/keV and 127.2±45.9 d, respectively.
Abstract
We report on the host association of FRB 20181030A, a repeating fast radio burst (FRB) with a low dispersion measure (103.5 pc cm
−3
) discovered by the CHIME/FRB Collaboration et al. Using ...baseband voltage data saved for its repeat bursts, we localize the FRB to a sky area of 5.3 arcmin
2
(90% confidence). Within the FRB localization region, we identify NGC 3252 as the most promising host with an estimated chance-coincidence probability <2.5 × 10
−3
. Moreover, we do not find any other galaxy with
M
r
< −15 AB mag within the localization region to the maximum estimated FRB redshift of 0.05. This rules out a dwarf host 5 times less luminous than any FRB host discovered to date. NGC 3252 is a star-forming spiral galaxy and at a distance of ≈20 Mpc, it is one of the closest FRB hosts discovered thus far. From our archival radio data search, we estimate a 3
σ
upper limit on the luminosity of a persistent compact radio source (source size < 0.3 kpc at 20 Mpc) at 3 GHz to be 2 × 10
26
erg s
−1
Hz
−1
, at least 1500 times smaller than that of the FRB 20121102A persistent radio source. We also argue that a population of young millisecond magnetars alone cannot explain the observed volumetric rate of repeating FRBs. Finally, FRB 20181030A is a promising source for constraining FRB emission models due to its proximity and we strongly encourage its multi-wavelength follow-up.
Abstract
We present observations of the high momentum tail in expanding Bose–Einstein condensates of metastable Helium atoms released from a harmonic trap. The far-field density profile exhibits ...features that support identification of the tails of the momentum distribution as originating in the in-situ quantum depletion prior to release. Thus, we corroborate recent observations of slowly-decaying tails in the far-field beyond the thermal component. This observation is in conflict with the hydrodynamic theory, which predicts that the in-situ depletion does not survive when atoms are released from a trap. Indeed, the depleted tails even appear stronger in the far-field than expected before release, and we discuss the challenges of interpreting this in terms of the Tan contact in the trapped gas. In complement to these observations, full quantum simulations of the experiment show that, under the right conditions, the depletion can persist into the far field after expansion. Moreover, the simulations provide mechanisms for survival and for the the large-momentum tails to appear stronger after expansion due to an acceleration of the depleted atoms by the mean-field potential. However, while in qualitative agreement, the final depletion observed in the experiment is much larger than in the simulation.
► Effect of the electrolyte on surface features of titanium oxide layer is significant. ► Titanium oxide layer formed in K3PO4 electrolyte shows high surface roughness. ► Titanium oxide layer formed ...in K3PO4 electrolyte shows good biological response.
The present work demonstrated the influence of phosphate electrolytes on surface characteristics and biological response of the titanium oxide layer formed via micro-arc oxidation coating. For this purpose, the present coatings were carried out on titanium samples using two different electrolytes containing Na3PO4 and K3PO4. The surface roughness of the oxide layer formed in K3PO4 electrolyte was higher than that in the Na3PO4 electrolyte. This was attributed to the higher fraction of the micropores in the oxide layer prepared by the K3PO4 electrolyte than that by the Na3PO4 electrolyte. From the results of simulated body fluid test, the precipitation and growth of amorphous calcium phosphate on the oxide layer formed in the K3PO4 electrolyte was superior to that in the Na3PO4 electrolyte due to the enhanced surface roughness. In addition, in vitro cell adhesion was triggered in case of the oxide layer formed in the K3PO4 electrolyte.
A detailed dielectric spectroscopy study was performed on polyvinylidene fluoride (PVDF) and PVDF/CsHSO
4
composites at temperatures 220 K ≤
T
≤ 340 K and frequencies 10 Hz ≤
ν
≤ 10
5
Hz. The ...observed dielectric spectra were described as a contribution of two relaxation processes and dc conductivity. The obtained relaxation time for each process revealed a saddle-like temperature dependence which could not be fitted to a single Arrhenius or Vogel-Fulcher-Tammann equation. This unusual temperature behavior was successfully analyzed using an empirical model previously proposed to interpret similar nonmonotonic behavior of the relaxation time in confined dielectric systems. A brief discussion is presented about a possibility that some part of the amorphous regions is confined by the surrounding crystalline regions and vice versa in PVDF and the composites.
Decreased oral clopidogrel absorption caused by induction of intestinal permeability glycoprotein (P‐gp) expression after aspirin administration was observed in rats. This study evaluated the effect ...of aspirin coadministration on the pharmacokinetics/pharmacodynamics of clopidogrel in humans. A single 75‐mg dose of clopidogrel was orally administered before and after 2 and 4 weeks of once‐daily 100‐mg aspirin administration in 18 healthy volunteers who were recruited based on CYP2C19 and PON1 genotypes. Plasma concentrations of clopidogrel and its active metabolite, H4, and relative platelet inhibition (RPI) were determined. The P‐gp microRNA miR‐27a increased by up to 7.67‐fold (P = 0.004) and the clopidogrel area under the concentration–time curve (AUC) decreased by 14% (P > 0.05), but the AUC of H4 remained unchanged and RPI increased by up to 15% (P = 0.002) after aspirin administration. These findings indicate low‐dose aspirin coadministration may decrease clopidogrel bioavailability but does not decrease its efficacy.
Clinical Pharmacology & Therapeutics (2014); 95 6, 608–616. doi:10.1038/clpt.2014.49
Magnetospheric compression due to impact of enhanced solar wind dynamic pressure Pdyn has long been considered as one of the generation mechanisms of electromagnetic ion cyclotron (EMIC) waves. With ...the Van Allen Probe‐A observations, we identify three EMIC wave events that are triggered by Pdyn enhancements under prolonged northward interplanetary magnetic field (IMF) quiet time preconditions. They are in contrast to one another in a few aspects. Event 1 occurs in the middle of continuously increasing Pdyn while Van Allen Probe‐A is located outside the plasmapause at postmidnight and near the equator (magnetic latitude (MLAT) ~ −3°). Event 2 occurs by a sharp Pdyn pulse impact while Van Allen Probe‐A is located inside the plasmapause in the dawn sector and rather away from the equator (MLAT ~ 12°). Event 3 is characterized by amplification of a preexisting EMIC wave by a sharp Pdyn pulse impact while Van Allen Probe‐A is located outside the plasmapause at noon and rather away from the equator (MLAT ~ −15°). These three events represent various situations where EMIC waves can be triggered by Pdyn increases. Several common features are also found among the three events. (i) The strongest wave is found just above the He+ gyrofrequency. (ii) The waves are nearly linearly polarized with a rather oblique propagation direction (~28° to ~39° on average). (iii) The proton fluxes increase in immediate response to the Pdyn impact, most significantly in tens of keV energy, corresponding to the proton resonant energy. (iv) The temperature anisotropy with T⊥ > T|| is seen in the resonant energy for all the events, although its increase by the Pdyn impact is not necessarily always significant. The last two points (iii) and (iv) may imply that in addition to the temperature anisotropy, the increase of the resonant protons must have played a critical role in triggering the EMIC waves by the enhanced Pdyn impact.
Key Points
Three EMIC wave events triggered by various dynamic pressure conditions
Exhibit proton flux increases in expected resonant energy
Exhibit temperature anisotropy with T⊥ > T|| in the resonant energy
AC-LGADs, also referred to as resistive silicon detectors, are a recent development of low-gain avalanche detectors (LGADs), based on a sensor design where the multiplication layer and n+ contact are ...continuous, and only the metal layer is patterned. In AC-LGADs, the signal is capacitively coupled from the continuous, resistive n+ layer over a dielectric to the metal electrodes. Therefore, the spatial resolution is not only influenced by the electrode pitch, but also the relative size of the metal electrodes. Signal propagation between the metallized areas and charge sharing between electrodes plays a larger role in these detectors than in conventional silicon sensors read out in DC mode. AC-LGADs from two manufacturers were studied in beam tests and with infrared laser scans. The impact of n+ layer resistivity and metal electrode pitch on the charge sharing and achievable position resolution is shown. For strips with 100 μm pitch, a resolution of ¡ 5 μm can be reached. The charge sharing between neighboring strips is investigated in more detail, indicating the induction of signal charge and subsequent re-sharing over the n+ layer. Furthermore, an approach to identify signal sharing over large distances is presented.
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