Peculiarities of the abundance of chemical elements in the atmosphere of PMMR23-red supergiant in the Small Magellanic Cloud due to interstellar gas accretion

The chemical composition of the PMMR23 red supergiant located in the Small Magellanic Cloud (SMC) is analyzed. The abundance of 35 chemical elements and the upper limits of abundance for Tl and U are found. The relative abundance of heavy elements is higher by 0.6–1.0 dex with respect to iron peak elements. The spectra of several SMC red supergiants PMMR27, PMMR28, and PMMR144—located in the region where the velocities of stars and interstellar gas are quite high— show the emission components in the wings of the hydrogen line. This emission is not detected for PMMR23. A possibility of interstellar gas accretion on the atmospheres of PMMR23 and other supergiants in Magellanic Clouds is discussed. The analysis is carried out using spectra measured at ESO 3.6 m telescope with the spectral resolving power R = 30000.     

Spitzer IRAC infrared colours of submillimetre-bright galaxies

High-redshift submillimetre-bright galaxies identified by blank field surveys at millimetre and submillimetre wavelengths appear in the region of the Infra Red Array Camera (IRAC) colour–colour diagrams previously identified as the domain of luminous active galactic nuclei (AGNs). Our analysis using a set of empirical and theoretical dusty starburst spectral energy distribution (SED) models shows that power-law continuum sources associated with hot dust heated by young (≲100 Myr old), extreme starbursts at z > 2 also occupy the same general area as AGNs in the IRAC colour–colour plots. A detailed comparison of the IRAC colours and SEDs demonstrates that the two populations are distinct from each other, with submillimetre-bright galaxies having a systematically flatter IRAC spectrum (≳1 mag bluer in the observed [4.5]–[8.0] colour). Only about 20 per cent of the objects overlap in the colour–colour plots, and this low fraction suggests that submillimetre galaxies powered by a dust-obscured AGN are not common. The red infrared colours of the submillimetre galaxies are distinct from those of the ubiquitous foreground IRAC sources, and we propose a set of infrared colour selection criteria for identifying SMG counterparts that can be used even in the absence of radio or Multiband Imaging Photometer for Spitzer (MIPS) 24 μm data.     

朝鲜平南盆地叠加褶皱构造特征

对于朝鲜平南盆地沉积盖层内发育的倒转褶皱,过去一般认为是直立褶皱的次级从属褶皱。通过对平南盆地内倒转褶皱发育区详细的地质调查,结合煤炭开发过程中获得的地质及钻探资料,提出平南盆地内叠加褶皱的主要识别标志为：地质平面图上呈现不同类型的两组褶皱脊线的交叉;倒转褶皱的轴面被直立褶皱改造弯曲;直立褶皱的两翼发育的倒转褶皱表现为两组牵引褶皱。查明了平南盆地存在3个阶段的褶皱构造：第一阶段为东西向的倒转褶皱,形成于印支期;第二阶段褶皱为东西向的直立褶皱,形成于早燕山期;第三阶段褶皱为北北东向的直立褶皱,形成于晚燕山期。     

Role of cold water and beta-effect in the formation of the East Korean Warm Current in the East/Japan Sea: a numerical experiment

The contributions of bottom cold water and planetary β-effect to the formation of the East Korean Warm Current (EKWC), the western boundary current in the East/Japan Sea (EJS), were evaluated using an idealized three-dimensional numerical model. The model results suggest that the bottom cold water and, to a lesser extent, the planetary β-effect both contribute to the formation of the EKWC. The cold water functions as the bottom of the upper layer, to control the EKWC via conservation of potential vorticity. It is known that cold waters, such as the North Korean Cold Water and Korea Strait Bottom Cold Water often observed during summer along the southwestern coast of the EJS, originate from the winter convection in the northern area. Observational studies consistently show that the EKWC strengthens in summer when the cold water extends further south along the western boundary.     

The Keylong Serai rock avalanche, NW Indian Himalaya: geomorphology and palaeoseismic implications

This paper describes the geomorphology of rock avalanche deposits that resulted from a major mountain slope failure at Keylong Serai on the north slope of the Indian High Himalaya, an area of high altitude desert. Cosmogenic ¹⁰Be exposure ages of the widespread deposits indicate their formation 7,510 ± 110 years BP. Proxy records for this region of the Himalaya imply a similar dry climatic regime to the present day at this time, suggesting that precipitation was an unlikely trigger for this rock avalanche. An alternative mechanism associated with rock-wall stress relaxation is also unlikely, given the earlier timing of deglaciation in this area. Given the enormous volume of debris generated by this event, the most likely trigger for this mountain collapse and resultant rock avalanche is high ground acceleration during a great earthquake (M > 8). It is proposed that rock avalanches can be used to extend the limited palaeoseismic record and improve information on the recurrence interval of great earthquakes within the Himalaya arc.     

A modified parallel IWAN model for cyclic hardening behavior of sand

A modified parallel IWAN model, which includes a cyclic hardening function, is proposed and verified. The proposed model consists of elasto-perfect plastic and isotropic hardening elements. The model is able to predict cyclic hardening behavior through the adjustment of the internal slip stresses of its elements beyond the cyclic threshold, and satisfies Bauschinger's effect and the Masing rule with its own behavior characteristics. The cyclic hardening function is developed based on the irrecoverable plastic strain (accumulated shear strain) of dry sand during shearing, which is assumed to be a summation of shear strain beyond the cyclic threshold. Symmetric-limit cyclic loading and irregular loading tests were performed to determine model parameters and to verify the behavior of the proposed model. Finally, a one-dimensional site response analysis program (KODSAP) is developed by using the proposed model. The effects of cyclic hardening behavior on site response are evaluated using KODSAP.     

Modelling the Asian summer monsoon using CCAM

A ten-year mean (1989–1998) climatology of the Asian summer monsoon is studied using the CSIRO Conformal-Cubic Atmospheric Model (CCAM) to downscale NCEP reanalyses. The aim of the current study is to validate the model results against previous work on this topic, in order to identify model strengths and weaknesses in simulating the Asian summer monsoon. The model results are compared with available observations and are presented in two parts. In the first part, the mean summer rainfall, maximum and minimum temperatures and winds are compared with the observations. The second part focuses on validation of the monsoon onset. The model captures the mean characteristics such as the cross-equatorial flow of low-level winds over the Indian Ocean and near the Somali coast, rainfall patterns, onset indices, northward movements, active-break and revival periods.     

Cloud/Fog Water Chemistry at a High Elevation Site in South Korea

Cloud/fog water samples were collected at Daekwanreung (840 m msl), a ridge site, in South Korea, from March 2002 to September 2003, by using a Caltech type, self fabricated active strand cloud water collector. The pH, electrical conductivity and major ion concentrations were analyzed. The cloud water pH ranged from 3.6 to 6.8 with an average of 5.2, which was close to the atmospheric neutral point. However, the pH calculated from average concentrations of H+ was 4.7, indicating the cloud/fog water was weakly acidified. SO₄ ²⁻, NO₃ ⁻ and NH₄ ⁺ are predominant ions of which average concentrations were 203.1, 128.1, and 211.7 μeq⋅L⁻¹, respectively. Samples were categorized into four groups by applying 48-hour back trajectory analysis, using the HYbrid Single-Particle Largrangian Integrated Trajectory (HYSPLIT) model. Chemical compositions for the four cases significantly differed from each other. For air masses transported from the East Sea (group E), sea salt concentrations, including Na⁺, Cl⁻ Mg²⁺, were relatively high. Principal acidifying pollutants, such as NO₃ ⁻ and nss-SO₄ ²⁻, significantly increased in the case of air masses transported from the Northeast Asian continent through North Korea (group N) and air masses from the Seoul metropolitan area (group W). However, the mean pH of group N was the highest while the mean pH of group W was the lowest. This suggests that most NO₃ ⁻ and nss-SO₄ ²⁻ in cloud/fog water was neutralized by ammonia and calcium compounds under the influence of air masses transported from Northeast Asia. N/S ratio for the group W was significantly higher than those for the other three groups, suggesting nitrogen species transported from the Seoul metropolitan area contributed to acidification of cloud/fog water at Daekwanreung. Principle Component analysis (PCA) was applied to the cloud/fog water data for presenting characteristics in the four different categories.     

Excess protactinium in phosphate nodules from a coastal upwelling zone

Measurements of²³¹Pa/²³⁵U and²³⁰Th/²³⁴U activity ratios have been made for a suite of Quaternary age phosphate nodules from the upwelling zone off Peru and Chile. Many of these samples contain more²³¹Pa than would be predicted based on closed-system²³⁰Th/²³⁴U ages unlike samples from non-upwelling environments which have been shown to have concordant²³¹Pa and²³⁰Th ages. Peru/Chile phosphate nodules apparently pick up²³¹Pa preferentially to²³⁰Th. This is most likely a result of prior fractionation of protactinium and thorium in the open ocean. Highly productive coastal upwelling zones may be added to the growing list of localities where fractionation between thorium and protactinium isotopes has been observed in marine sediments.