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We have found a class of circular radio objects in the Evolutionary Map of the Universe Pilot Survey, using the Australian Square Kilometre Array Pathfinder telescope. The objects appear in radio images as circular edge-brightened discs, about one arcmin diameter, that are unlike other objects previously reported in the literature. We explore several possible mechanisms that might cause these objects, but none seems to be a compelling explanation.
Panchromatic modeling is one of the most powerful tools at our disposal to measure reliably the physical properties of galaxies across cosmic times. We present here an entirely new implementation in python of one such tool: CIGALE. Developed along three main design principles: simplicity, modularity, and efficiency, it has proven to be a versatile code that in addition to estimating the physical properties of galaxies (or regions within galaxies), can generate arbitrary sets of theoretical models or be used as a library to build other tools. Among its defining features, it is a truly panchromatic code ranging from the far-ultraviolet to the radio that takes into account numerous physical components (including active nuclei or synchrotron emission), that can fit non-photometric data, handle upper limits, determine photometric redshifts, and even build mock catalogs.
We present ALMA detection of the [O iii] 88 μm line and 850 μm dust continuum emission in a Y-dropout Lyman break galaxy, MACS0416_Y1. The [O iii] detection confirms the object with a spectroscopic redshift to be z = 8.3118±0.0003. The 850 μm continuum intensity (0.14 mJy) implies a large dust mass on the order of 4×106M⊙. The ultraviolet-to-far infrared spectral energy distribution modeling, where the [O iii] emissivity model is incorporated, suggests the presence of a young (τage ≍ 4 Myr), star-forming (SFR ≍ 60M⊙yr−1), and moderately metal-polluted (Z ≍ 0.2Z⊙) stellar component with a stellar mass of 3 × 108M⊙. An analytic dust mass evolution model with a single episode of star formation does not reproduce the metallicity and dust mass in ≍ 4 Myr, suggesting an underlying evolved stellar component as the origin of the dust mass.
We observed the 2 July 2019 total solar eclipse with a variety of imaging and spectroscopic instruments recording from three sites in mainland Chile: on the centerline at La Higuera, from the Cerro Tololo Inter-American Observatory, and from La Serena, as well as from a chartered flight at peak totality in mid-Pacific. Our spectroscopy monitored Fe X, Fe XIV, and Ar X lines, and we imaged Ar X with a Lyot filter adjusted from its original H-alpha bandpass. Our composite imaging has been compared with predictions based on modeling using magnetic-field measurements from the pre-eclipse month. Our time-differenced sites will be used to measure motions in coronal streamers.
The present study, which was carried out on a deep weathering profile of quartz diorite in the San'in district, Japan, along with two lateritic samples from India and Sri Lanka, provides convincing evidence supporting the dissolution and recrystallization mechanism for the halloysite-to-kaolinite transformation during weathering of crystalline rocks. In all the samples studied, tubular halloysite formed prior to kaolinite via the dissolution of feldspars and precipitation from solution. The crystal size distribution of tubular halloysite formed early was characterized by a lognormal curve having a positive asymmetry. When the activity of water decreased in the weathering profile, halloysite as well as goethite began to dehydrate, which acted as a trigger for dissolving halloysite. The heterogeneous nucleation of kaolinite took place on the edges and in the shrinkage pores of dehydrated halloysite tubes. The topotactic relationship of b*halloysite//b*kaolinite was kept between the substrate halloysite and the product kaolinite in the incipient growing stages of kaolinite. As a consequence, early formed halloysite transforms to kaolinite in a cannibalistic manner over a long period of time, owing to the intermittent supply of solution undersaturated with respect to halloysite in natural open systems.
A range of allophane samples (atomic AI/Si bulk ratios 1.1-1.9) from Silica Springs, New Zealand, has been characterized by X-ray photoelectron spectroscopy (XPS). Binding energies of Si 2s, Si 2p, Al 2p, O 1s, C 1s, and N 1s electrons, together with the kinetic energies of Al KL23L23 Auger electrons, at or near the surface of allophane aggregates, have been derived. The values for Al, Si and O electrons are similar to those for kaolinite but also to those for some framework silicates (feldspars) having 4-coordinate Al. Values for N electrons suggest that N occurs in organic structures. Comparison of XPS and bulk Al/Si ratios shows an enrichment of Al at or near the surface of allophane aggregates. The same is true for C and N. Extraction with citrate-dithionite-bicarbonate (CDB) reagent leaves the surfaces depleted in Al. The CDB extracts have higher Al/Si ratios than the bulk allophanes. Similarly, CDB treatment reduces the degree of surface enrichment of C and N. Small increases in the binding energies of Si electrons following CDB treatment suggest partial dissolution of the bulk structure though a concomitant removal of a separate phase or species cannot be ruled out. The results may be accounted for in terms of the structure previously suggested for the primary spherules of Silica Springs allophane (Childs et al., 1990) though the composition of the spherules at or near the surface of the allophane aggregates is different from those of the bulk.
Tabanids are haematophagous flies feeding on livestock and wildlife. In the absence of information on the relationship of tabanid flies and protozoan parasites in South Africa and Zambia, the current study was aimed at characterizing tabanid flies collected in these two countries as well as detecting protozoan parasites they are harbouring. A total of 527 tabanid flies were collected whereby 70·2% were from South Africa and 29·8% were from Zambia. Morphological analysis revealed a total of five different genera collected from the sampled areas namely: Ancala, Atylotus, Haematopota, Philoliche and Tabanus. DNA extracted from South African Tabanus par and Tabanus taeniola tested positive for the presence of Trypanosoma congolense (Savannah) and Trypanosoma theileri whilst one member from T. par was positive for Trypanosoma brucei species. DNA extracted from Zambian tabanid flies tested positive for the presence of Besnoitia species at 1·27% (2/157), Babesia bigemina 5·73% (9/157), Theileria parva 30·11% (30/157) and 9·82% (14/157) for Trypanosoma evansi. This study is the first to report on relationship of Babesia and Theileria parasites with tabanid flies. Further investigations are required to determine the role of tabanids in transmission of the detected protozoan parasites in livestock and wildlife in South Africa and Zambia.
The objectives of this study were to infer phenotypic causal networks involving gestation length (GL) and calving difficulty (CD) for the primiparity of 1850 Japanese Black heifers, and the birth weight (BWT), withers height (WH) and chest girth (CHG) of their full blood calves, and to compare the causal effects among them. The inductive causation (IC) algorithm was employed to search for causal links among these traits; it was applied to the posterior distribution of the residual (co)variance matrix of a multiple-trait sire-maternal grand sire (MGS) model. The IC algorithm implemented with 95% and 90% highest posterior density intervals detected only one structure with links between GL and BWT (WH or CHG) and between BWT (WH or CHG) and CD, although their directions were not resolved. Therefore, a possible causal structure based on the networks obtained from the IC algorithm [GL→BWT (WH or CHG)→CD] was fitted using a structural equation model to infer causal structure coefficients between the traits. The structural coefficients of GL on BWT and of BWT on GL on the observable scale showed that an extra day of GL led to a 270-g gain in BWT, and a 1-kg increase in BWT increased the risk for dystocia by 1.1%, in the causal structure. Similarly, an increase in GL by 1 day resulted in a 2.1 (2.0)-mm growth in WH (CHG), and a 1-cm increase in WH (CHG) increased the risk of dystocia by 1.2% (0.9%). The structural equation model was also fitted to alternative causal structures, which involved the addition of a directed link from GL to CD, or GL→CD to the structures described above. The inferred structural coefficients with the alternative structures were almost the same as the corresponding ones that had GL→BWT (WH or CHG)→CD. However, the direct causal effect of the extra link from GL on CD was similar to the indirect causal effect of GL through the mediating effect of BWT (WH or CHG) on CD and significant (P<0.05). This suggest that maternal genetic effects might not be removed completely from the residual variance components in the sire-MGS model, and the application of the IC algorithm to the variances from the model could detect an incorrect structure. Nonetheless, fitting the structural equation model to the causal structure provided useful information such as the magnitude of the causal effects between the traits.
Lake-level changes inferred from seismic surveying and core sampling of the floor of Lake Baikal near the Selenga River delta can be used to constrain regional climatic history and appear to be correlated to global climate changes represented by marine oxygen isotope stages (MIS). The reflection pattern and correlation to the isotope stages indicate that the topset and progradational foreset sediments of the deltas formed during periods of stable lake levels and warm climatic conditions. During warm stages, the lake level was high, and during cold stages it was low. The drop in the lake level due to cooling from MIS 5 through MIS 4 is estimated to be 33–38 m; from MIS 3 through MIS 2, it fell an additional 11–15 m. Because the lake level is chiefly controlled by evaporation and river input, we infer that more water was supplied to Lake Baikal during warm stages.
Chikungunya virus (CHIKV) and Ross River virus (RRV) of the genus Alphavirus, family Togaviridae are mainly transmitted by Aedes mosquitoes and the symptoms they cause in patients are similar to dengue. A chikungunya (CHIK) outbreak re-emerged in several Asian countries during 2005–2006. This study aimed to clarify the prevalence of CHIKV infection in suspected dengue patients in six countries in South Asia and Southeast Asia. Seven hundred forty-eight serum samples were from dengue-suspected patients in South Asia and Southeast Asia, and 52 were from patients in Fiji. The samples were analysed by CHIKV IgM capture ELISA, CHIKV IgG indirect ELISA and focus reduction neutralization test against CHIKV or RRV. CHIK-confirmed cases in South Asia, particularly Myanmar and Sri Lanka, were 4·6%, and 6·1%, respectively; and in Southeast Asia, particularly Indonesia, the Philippines and Vietnam, were 27·4%, 26·8% and 25·0%, respectively. It suggests that CHIK was widely spread in these five countries in Asia. In Fiji, no CHIK cases were confirmed; however, RRV-confirmed cases represented 53·6% of suspected dengue cases. It suggests that RRV is being maintained or occasionally entering from neighbouring countries and should be considered when determining a causative agent for dengue-like illness in Fiji.
C band backscatter parameters contain information about the upper snowpack/firn in the dry snow zone. The wide incidence angle diversity of the Advanced Scatterometer (ASCAT) gives unprecedented characterisation of backscatter anisotropy, revealing the backscatter response to climatic forcing. The A (isotropic component) and M2 (bi-sinusoidal azimuth anisotropy) parameters are investigated here, in conjunction with data from atmospheric and snowpack models, to identify the backscatter response to surface forcing parameters (wind speed and persistence, precipitation, surface temperature, density and grain size). The long-term mean A parameter is successfully recreated with a regression using these drivers, indicating strong links between the A parameter and precipitation on long timescales. While the ASCAT time series is too short to determine which factors drive observed trends, factors influencing the seasonal and short timescale variability are revealed. On these timescales, A strongly responds to the propagation of surface temperature cycles/anomalies downward through the firn, via direct modulation of the dielectric constant. The influence of precipitation on A is small at shorter timescales. The M2 parameter is controlled by wind speed and persistence, through modification of monodirectionally-aligned surface roughness. This variability indicates that throughout much of coastal Antarctica, a microwave ‘snapshot’ is generally not representative of longer-term conditions.
Here we discuss requirements for high performance and solution processable organic semiconductors, by presenting a systematic investigation of 7-alkyl-2-phenylbenzothieno[3,2-b]benzothiophenes (Ph-BTBT-Cn’s). We found that the solubility and thermal properties of Ph-BTBT-Cn’s depend systematically on the substituted alkyl-chain length n. The observed features are well understood in terms of the change of molecular packing motif with n: The compounds with n ≤ 4 do not form independent alkyl chain layers, whereas those with n ≥ 5 form isolated alkyl chain layers. The latter compounds afford a series of isomorphous bilayer-type crystal structures that form two-dimensional carrier transport layers within the crystals. We also show that the Ph-BTBT-C10 afford high performance single-crystalline field-effect transistors the mobility of which reaches as high as 15.9 cm2/Vs. These results demonstrate a crucial role of the substituted alkyl chain length for obtaining high performance organic semiconductors and field-effect transistors.
Meiotic maturation of oocytes requires a variety of ATP-dependent reactions, such as germinal vesicle breakdown, spindle formation, and rearrangement of plasma membrane structure, which is required for fertilization. Mitochondria are accordingly expected be localized to subcellular sites of energy utilization. Although microtubule-dependent cellular traffic for mitochondria has been studied extensively in cultured neuronal (and some other somatic) cells, the molecular mechanism of their dynamics in mammalian oocytes at different stages of maturation remains obscure. The present work describes dynamic aspects of mitochondria in porcine oocytes at the germinal vesicle stage. After incubation of oocytes with MitoTracker Orange followed by centrifugation, mitochondria-enriched ooplasm was obtained using a glass needle and transferred into a recipient oocyte. The intracellular distribution of the fluorescent mitochondria was then observed over time using a laser scanning confocal microscopy equipped with an incubator. Kinetic analysis revealed that fluorescent mitochondria moved from central to subcortical areas of oocytes and were dispersed along plasma membranes. Such movement of mitochondria was inhibited by either cytochalasin B or cytochalasin D but not by colcemid, suggesting the involvement of microfilaments. This method of visualizing mitochondrial dynamics in live cells permits study of the pathophysiology of cytoskeleton-dependent intracellular traffic of mitochondria and associated energy metabolism during meiotic maturation of oocytes.