[en] Sixteen patients who had a nasopharyngeal carcinoma (NPC) who were treated with radiation therapy were followed up after a median duration of 5.5 years and given a battery of neuropsychological tests. Results were compared with a comparable group of newly diagnosed NPC patients awaiting radiation therapy. The irradiated group was significantly poorer in overall IQ, non-verbal memory recall, and reported a substantially greater number of memory related complaints. These results contrast with the complacent general assumption that radiation therapy has a negligible effect on adult functioning. (author)

[en] We report the crystal growth of NaBaR(BO₃)₂ (R = Dy, Ho, Er and Tm) by the flux method. In the rhombohedral crystal structures, [RO₆] octahedra and planar [BO₃] units connect by bridging O atoms, forming triangular layers in the ab plane that are evenly spaced along c. Two perfectly triangular rare earth layers of identical dimension are found. Anisotropic magnetic susceptibility is observed for all; NaBaEr(BO₃)₂ is nearly isotropic while NaBaTm(BO₃)₂ is the most anisotropic. Heat capacity measurements reveal no long-range magnetic ordering down to 0.35 K for R = Dy or Er, while the Ho material displays a significant entropy loss. All the magnetic entropy appears to be absent in the Tm case by low temperature, suggesting that a singlet ground state may have formed. (paper)

[en] Recently, some studies showed that the GeV gamma-ray excess signal from the central Milky Way can be explained by the annihilation of ∼ 40 GeV dark matter through the bb̄ channel. Based on the morphology of the gamma-ray flux, the best-fit inner slope of the dark matter density profile is γ = 1.26. However, recent analyses of the Milky Way dark matter profile favor γ = 0.6 – 0.8. In this article, we show that the GeV gamma-ray excess can also be explained by the Sommerfeld-enhanced dark matter annihilation through the bb̄ channel with γ = 0.85 – 1.05. We constrain the parameters of the Sommerfeld-enhanced annihilation by using data from Fermi-LAT. We also show that the predicted gamma-ray fluxes emitted from dwarf galaxies generally satisfy recent upper limits on gamma-ray fluxes detected by Fermi-LAT. (paper)

[en] Ba₄NbMn₃O₁₂ is reported, synthesized by a solid state method in air. The crystal structure, determined by performing refinements on room temperature powder x-ray diffraction data by the Rietveld method, consists of Mn₃O₁₂ trimers in the configuration of three face-sharing MnO₆ octahedra, with the trimers arranged in triangular planes. An effective moment of 4.82 μ _B/f.u is observed and competing antiferromagnetic and ferromagnetic interactions between Mn ions are inferred from the Weiss temperature of −4 K and the ferrimagnetic ordering transition of approximately 42 K. Ba₄NbMn₃O₁₂ is a semiconductor with a transport activation energy of 0.37 eV. (paper)

[en] Recently, a very strong correlation between the central surface density of stars and dynamical mass in 135 disk galaxies has been obtained. It has been shown that this central-surface-densities relation agrees very well with Modified Newtonian Dynamics (MOND). In this article, we show that if we assume the baryons have an isothermal distribution and dark matter exists, then it is possible to derive by means of the Jeans equation an analytic central-surface-densities relation connecting dark matter and baryons that agrees with the observed relation. We find that the observed central-surface-densities relation can also be accommodated in the context of dark matter provided the latter is described by an isothermal profile. Therefore, the observed relation is consistent with not only MOND. (paper)

[en] Highlights: • TmMgGaO₄ crystallizes in the R-3m space group with the YbFe₂O₄ structure. • TmMgGaO₄ exhibits geometric magnetic frustration with no ordering down to 1.8 K. • Magnetic properties of TmMgGaO₄ are highly anisotropic. - Abstract: The crystal growth, structure, and basic magnetic properties of TmMgGaO₄ are reported. The Tm ions are located in a planar triangular lattice consisting of distorted TmO₆ octahedra, while the Mg and Ga atoms randomly occupy intermediary bilayers of M-O triangular bipyramids. The Tm ions are positionally disordered. The material displays an antiferromagnetic Curie Weiss theta of ∼−20 −25 K, with no clear ordering visible in the magnetic susceptibility down to 1.8 K; the structure and magnetic properties suggest that ordering of the magnetic moments is frustrated by both structural disorder and the triangular magnetic motif. Single crystal magnetization measurements indicate that the magnetic properties are highly anisotropic, with large moments measured perpendicular to the triangular planes. At 2 K, a broad step-like feature is seen in the field-dependent magnetization perpendicular to the plane on applied field near 2 T.

[en] Highlights: • Use monthly data to estimate Hong Kong energy demands' price responsiveness. • Find retail demands for electricity and town gas to be highly price-inelastic. • Measure the impact of a 40% electricity rate increase on retail energy consumption. • Document a small demand-side impact on Hong Kong's annual CO₂ emissions. • Make policy recommendations for Hong Kong's electricity future. This paper estimates the consumption effects of an electricity rate increase triggered by an electricity decarbonization policy's implementation. Underscoring its real-world relevance is the policy's net impact on CO₂ emissions, the sum of (a) the supply-side impact attributable to using generation resources with low emissions to displace those with high emissions, and (b) the demand-side impact caused by energy consumption changes in response to the electricity rate increase. For Hong Kong, the changes in (b) are decreases in electricity consumption and increases in town gas consumption. Using a sample of monthly data for the period of 1981–2016, we document the low price responsiveness of Hong Kong's electricity and town gas demands by customer class (residential, commercial and industrial). Hence, the 40% projected electricity rate increase due to Hong Kong's adopted electricity decarbonization policy may only have a small demand-side impact on CO₂ emissions. Finally, the electricity demands' low price responsiveness has two important policy implications. First, Hong Kong's demand-side-management should rely more on energy-efficiency improvements than price-induced consumption reductions. Second, restructuring Hong Kong's electricity industry to introduce wholesale competition should consider the potential for large electricity price spikes and market power abuse in connection to price-inelastic electricity demands.

[en] We report measurements of ⁵⁷Fe Mössbauer spectra for RFe₂Zn₂₀ (R = Lu, Yb, Gd) from  ∼4.5 K to room temperature. The obtained isomer shift values are very similar for all three compounds, their temperature dependence was analyzed within the Debye model and resulted in an estimate of the Debye temperatures of 450–500 K. The values of quadrupole splitting at room temperature change with the cubic lattice constant a in a linear fashion. For GdFe₂Zn₂₀, ferromagnetic order is seen as an appearance of a sextet in the spectra. The ⁵⁷Fe site hyperfine field for $T\to <!--\; ???\; -->0$ was evaluated to be  ∼2.4 T. (paper)

[en] We study the evolution of the Kondo effect in heavy fermion compounds, Yb(Fe_1_-_xCo_x)_2Zn_2_0 (0 ≲ x ≲ 1), by means of temperature-dependent electric resistivity and speci c heat. The ground state of YbFe_2Zn_2_0 can be well described by a Kondo model with degeneracy N = 8 and a T_K ~30 K. In the presence of a very similar total CEF splitting with YbFe_2Zn_2_0, the ground state of YbCo_2Zn_2_0 is close to a Kondo state with degeneracy N = 2 and a much lower TK ~ 2 K. Upon Co substitution, the coherence temperature of YbFe_2Zn_2_0 is suppressed, accompanied by an emerging Schottky-like feature in speci c heat associated with the thermal depopulation of CEF levels upon cooling. For 0.4 ≲ x ≲ 0.9, the ground state remains roughly the same which can be qualitatively understood by Kondo effect in the presence of CEF splitting. There is no clear indication of Kondo coherence observable in resistivity within this substitution range down to 500 mK. The coherence re-appears at around x≳ 0.9 and the coherence temperature increases with higher Co concentration levels.

[en] Highlights: • PFRs and BPA were ubiquitous in PM_2.5 and dust in kindergartens and primary schools in Hong Kong. • EDI values of TPHP in dust non-dietary intake fraction were higher than others. • A significant correlation was found between PM_2.5 samples and indoor dust in the levels of TCEP. • TPHP and TCEP in primary schools were obviously lower than those in kindergartens. • TDCP and TCEP were dominant in PM_2.5 samples, while TPHP and TDCP were dominant in indoor dust. Organophosphate flame retardants (PFRs) and bisphenol A (BPA) were measured in indoor dust and PM_2.5 samples from nine kindergartens and two primary schools in Hong Kong. The average levels of PM_2.5 ranged from 4.0E+03 ng/m³ to 1.5E+04 ng/m³. Average levels of PFRs (from 1.5 ng/m³ to 20 ng/m³ in PM_2.5; from 8.0E−02 μg/g dw to 2.4 μg/g dw in dust) and BPA (from 6.4E−01 ng/m³ to 1.0 ng/m³ in PM_2.5; from 1.0E−02 μg/g dw to 2.0E−01 μg/g dw in dust) were detected in most of the sampling sites. Tri-(2-Chloroethyl) phosphate (TCEP), tris(1,3-Dichloro-2-propyl) phosphate (TDCP), tris-(chloroisopropyl) phosphate (TCPP), and triphenyl phosphate (TPHP) were present in low levels in PM_2.5 with medians of 16, 14, 8.7, and 3.2 ng/m³, respectively. In dust, the medians were 1.5E−01, 5.5E−02, 5.9E−01, 8.6E−01, and 8.5E−02 μg/g dw for TCEP, TCPP, TDCPP, TPHP, and 2-ethylhexyl diphenyl phosphate, respectively. The medians of BPA were 6.4E−01 ng/m³ and 7.4E−02 μg/g dw for PM_2.5 and dust, respectively. A positive correlation was found between indoor PM_2.5 and dust in the levels of TCEP (r = 0.85; p = .05). In the individual classroom in this survey, the predominant PFRs were similar, that is, TDCP and TCEP in indoor PM_2.5 while TPHP and TDCP in dust. TPHP and TCEP in primary schools were obviously lower than those in kindergartens. The estimated daily intakes via PM_2.5 and dust for all selected PFRs ranged from 1.3E−4 μg/kg/d to 2.0E−02 μg/kg/d, and the value of less than the detection limit at 3.5E−4 μg/kg/d was found for BPA. The EDI values of TPHP in dust non-dietary intake fraction were higher than those in the others. Calculated hazard indices (EDI/RfD) ranged from 4.8E−06 and 5.5E−03, showing that PFRs and BPA in PM_2.5 and dust presented no health risks to children.