Wetlands embedded in agroecosystems provide vital ecosystem services (i.e., freeze protection, water retention, nutrient cycling, biodiversity support). However, they are particularly susceptible to invasion by nonnative species. West Indian marsh grass [Hymenachne amplexicaulis (Rudge) Nees] is a major wetland invader in Florida. Despite the documented consequences of H. amplexicaulis invasions, the landscape factors influencing the spread of this species are poorly understood. In this study, we asked whether landscape factors associated with wetland isolation, connectivity, and land management influence the presence of H. amplexicaulis among wetlands embedded in pastures. We recorded the presence or absence of H. amplexicaulis in 158 seasonal wetlands embedded in different pasture types (semi-natural vs. intensively managed). Wetland area, isolation from neighboring wetlands, isolation from the nearest source ditch, and connectivity were determined using a geographic information system (GIS). We related landscape factors to H. amplexicaulis using generalized linear models and model selection based on the second-order Akaike information criterion. Hymenachne amplexicaulis was first detected at the study site in the early 2000s. By 2018, we observed this species in 66% of the surveyed wetlands. The likelihood of observing H. amplexicaulis was higher in wetlands embedded in semi-natural pastures and higher in less isolated wetlands, especially when connected to a ditch. These results indicate that H. amplexicaulis spreads both overland (during seasonal flooding) and via the ditch network. Future work is needed to understand whether seeds or stolons are the primary invasion propagule and whether the species forms a persistent seed bank that could slow down restoration efforts. Additionally, further research is required to understand the ecological impact of this highly invasive plant in Florida wetlands.

The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.

The Proterozoic Sushina Hill Complex is the only agpaitic complex, reported from India and is characterized by a eudialyte-rinkite-bearing nepheline syenite. The complex is considered a ‘metamorphosed agpaitic complex'. This study describes the mineral assemblages formed during successive stages of evolution from magmatic to hydrothermal stages and low-temperature subsolidus re-equilibration assemblage. The primary-late magmatic assemblage is characterized by albite, orthoclase, unaltered nepheline, zoned diopside-hedenbergite, rinkite, late magmatic eudialyte and magnesio-arfvedsonite formed at ∼700°C with maximum aSiO2 of 0.60. In contrast, a deuteric assemblage (400-348°C) is represented by aegirine-jadeite-rich clinopyroxene, post-magmatic eudialyte, sodalite, analcime and the decomposition assemblages formed after eudialyte with decreasing aSiO2 (0.52-0.48). A further low-temperature subsolidus assemblage (≤250°C) represented by late-forming natrolite could be either related to regressive stages of metamorphism or a continuum of the subsolidus processes. Considering the P/T range of the greenschist - lower-amphibolite facies of metamorphism it is evident that the incorporation of a jadeite component within pyroxene is related to a subsolidus process between ∼400°C and 348°C in a silica deficient environment. We emphasize that the deuteric fluid itself acted as an agent of metamorphism and the decomposition assemblage formed after eudialyte is retained even after metamorphism due to the convergence of subsolidus and metamorphic domains. The formation of jadeite-rich aegirine is not considered to result from metamorphism. Overall it is near-impossible to discern any bona fide metamorphic textures or mineral assemblages in these syenites which appear to preserve a relict mineralogy regardless of their occurrence in country rocks which have experienced greenschist - amphibolite facies metamorphism. The Sushina complex is very similar in this respect to the Norra Kärr complex (Sweden).

Urinary tract infection (UTI) is common in children aged <5 years with diarrhoea, but little is known about risk factors, aetiology and outcome of such children. We aimed to evaluate these knowledge gaps of UTI in children aged <5 years with diarrhoea. We enrolled all children aged <5 years with diarrhoea admitted to Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh, between May 2011 and April 2013, who had history of fever (⩾38 °C) and obtained a urine sample for culture. Diarrhoea with UTI (confirmed by culture) constituted cases (n = 26) and those without UTI constituted controls (n = 78). Threefold controls were randomly selected. The case-fatality rate was comparable in cases and controls (4% vs. 1%, P = 0·439). Escherichia coli (69%) and Klebsiella (15%) were the most commonly isolated pathogens. Persistent diarrhoea, pneumonia and prior antibiotics use were identified as risk factors for UTI in logistic regression analysis (P < 0·05 for all). Thus, children with diarrhoea presenting with persistent diarrhoea, pneumonia, and prior antibiotic use should be investigated for UTI for their prompt management that may reduce morbidity.

Direct numerical simulation was used to study laminar and turbulent flows in circular pipes with smoothly corrugated walls. The corrugation wavelength was kept constant at $0.419D$, where $D$ is the mean diameter of the wavy-wall pipe and the corrugation height was varied from zero to $0.08D$. Flow rates were varied in steps between low values that generate laminar flow and higher values where the flow is in the post-transitional turbulent regime. Simulations in the turbulent regime were also carried out at a constant Reynolds number, $\mathit{Re}_{{\it\tau}}=314$, for all corrugation heights. It was found that even in the laminar regime, larger-amplitude corrugations produce flow separation. This leads to the proportion of pressure drop attributable to pressure drag being approximately 50 %, and rising to approximately 85 % in transitional rough-wall flow. The near-wall structure of turbulent flow is seen to be heavily influenced by the effects of flow separation and reattachment. Farther from the wall, the statistical profiles examined exhibit behaviours characteristic of smooth-wall flows or distributed roughness rough-wall flows. These observations support Townsend’s wall-similarity hypothesis. The organized nature of the present roughness allows the mean pressure drop to be written as a function of the corrugation height. When this is exploited in an analysis of the mean dynamical equation, the scaling problem is explicitly revealed to result from the combined influences of roughness and Reynolds number. The present results support the recent analysis and observations of Mehdi et al. (J. Fluid Mech., vol. 731, 2013, pp. 682–712), indicating that the length scale given by the distance from the wall at which the mean viscous force loses leading order is important to describing these combined influences, as well as providing a dynamically self-consistent connection to the scaling structure of smooth-wall pipe flow.

Residues of methomyl in rape plants and seed were determined after its application for bertha armyworm control. In one experiment application of 3 oz of methomyl per acre left 17 p.p.m. residue on the rape plants immediately after application. This level rapidly declined to 1.5, 1.0, 0.4, and 0.2 p.p.m. 1, 2, 5, and 9 days later, respectively, and no residue was detected (less than 0.02 p.p.m.) in seed harvested 22 days after application of the toxicant. Rape plant samples collected from several farms immediately after the application of 3 to 4 oz of methomyl per acre had 2.5 to 16 p.p.m. residues, indicating inefficient application of the insecticide in some cases. Analysis of rape seed samples collected from 36 farms showed little residue in three samples (0.02 to 0.03 p.p.m.) and none in 33, indicating that the use of methomyl for bertha armyworm control is not likely to contaminate rape seed with undesirable levels of residues.

The plasma parameters for the fast deposition of highly crystallized microcrystalline silicon (µc-Si) films with low defect density are presented using a high-density and low-temperature SiH4-H2 mixture microwave plasma. A very high deposition rate of $\sim $ 65 Å/s was achieved for a SiH4 concentration of 67% diluted in H2 with a high Raman crystallinity I c/I a > 2.5 and a low defect density of 1−2 × 1016 cm−3 by adjusting the plasma conditions. Contrary to the case of a conventional rf plasma, the defect density of the µc-Si films strongly depends on substrate temperature, T s, and increases with increasing T s even if T s is below 300 °C. This indicates that the real temperature at the growing surface is higher than the monitored value. A sufficient supply of deposition precursors such as SiH3 at the growing surface under an appropriate ion bombardment is effective for the fast deposition of highly crystallized µc-Si films as well as for the suppression of the amorphous incubation and transition interface layers at the initial growth stage.

A fast-firing technique for the sintering of lead magnesium niobate relaxor ceramics at relatively low temperature has been described. In this process, the samples containing excess PbO (up to 5 wt. %) are directly introduced into a furnace maintained at a temperature of 950 °C and kept there for 15–80 min, followed by a postsintering annealing treatment at 800 °C for 10 h. The importance of fast heating as well as annealing treatment has been justified. The sintered samples are near-phase-pure perovskite materials showing high bulk densities (>94%), uniform and dense microstructure, and satisfactory dielectric properties (Kmax > 13,000). The technique is simple and economic, does not require any controlled atmosphere, and minimizes hazards from lead volatilization.

In this work we have developed a model for the kinetics of the energy transfer from the host lattice to the core states of rare earth (RE) centers. We have derived a set of kinetics differential equations of RE luminescence in p-type semiconductor. Numerically computed rise and decay time of RE luminescence as a function of excitation power shows good agreement with the experimental data obtained for p-type GaAs:Nd.

Observations with the Wide Field Camera on HST were examined, and 27 Cepheids were discovered. Photometry and period analysis have produced unambiguous light curves free of alias. The observed P-L relation has a slope consistent with seminal calibration studies of Galactic and LMC Cepheids. An apparent distance modulus (in V) of 28.47 ± 0.10 to IC 4182 is derived. This implies that Mv(max) for SNIa 1937C is -19.92 ± 0.2 mag, independent of everything except differential absorption between the Cepheids and the supernova. Using this to calibrate Hubble diagrams for SNIa by several authors, and allowing for a 1-σ uncertainty in the absolute magnitude from the calibration of only one SNIa, we obtain H0 = 45 ± 14kms-1Mpc-1.

After Nichrome, Ni, Cr, and Au/Ta films are deposited onto single crystals of cubic SiC, their reactivities at the metal-semiconductor interface are studied by Auger Electron Spectroscopy. For all metals except Ni, metal carbides are detected at the interfaces. Initially these carbides tend to promote adhesion and limit the reaction with the substrate. Annealing at or above 450°C causes Ni to diffuse into the SiC and the Ta and Cr films to migrate through the capping material and away from the SiC, thereby delaminating. Development of the secondary phases at interface severely complicates the interpretation of the depth profiling data and with the uniformity of the contact film. These phases seem to be initiated at SiC defect sites where the reaction kinetics are considerably different and may be minimized with improved SiC substrates.

Investigation of stellar spectra has been active during the last four years. Without attempting to make a complete survey, some important researches may be mentioned.

The theory of the intensities and contours of absorption lines has been discussed by Eddington, Milne, Pannekoek, Woolley, H. H. Plaskett, and others, and has proved to be difficult. For example, no quantitative theory has yet been developed for the residuai intensity which remains in even the strongest lines, although the physical causes underlying the formation of residual intensities are rather obvious. Study of solar lines with light which has left the surface at different angles shows that the processes which produce the wings and the centre are probably different. The most promising line of attack on this intricate problem appears to be in studies of the solar spectrum, where different regions of the disc may be separately investigated, rather than of integrated starlight. The highest dispersion available, even in solar work, will be none too great.