Optical and mid-infrared neon abundance determinations in star-forming regions

We employed observational spectroscopic data of star-forming regions compiled from the literature and photoionization models to analyse the neon ionic abundances obtained using both optical and mid-infrared emission-lines. Comparing Ne++/H+ ionic abundances from distinct methods, we found that, in average, the abundances obtained via IR emission-lines are higher than those obtained via optical lines by a factor of 4. Photoionization models with abundance variations along the radius of the hypothetical nebula provide a possible explanation for a large part of the difference between ionic abundances via optical and infrared emission-lines. Ionization Correction Factor (ICF) for the neon is obtained from direct determinations of ionic fractions using infrared emission-lines. A constant Ne/O ratio (logNe/O \approx -0.70) for a large range of metallicity, independently of the ICF used to compute the neon total abundance is derived.Comment: 17 pages, 14 figures, accepted by MNRA

Sooty Falcon Falco concolor reproduction and population dynamics on the islands in the Sea of Oman

Knowledge of demographic parameters affecting population dynamics is critical to the formulation of effective conservation strategies. Sooty Falcon Falco concolor is a little-studied, Near-threatened species; estimates of global population size and trend for this species are uncertain. They lay eggs during mid-summer and sometimes nest in colonies. This unusual breeding ecology suggests that demographic parameters driving their population growth rate may differ from those of most other falcons. We studied Sooty Falcon reproduction at breeding aggregations on Fahal Island and the Daymaniyat islands in the Sea of Oman during 2007–2014, modelled population growth and identified important life history parameters using elasticity analysis. The mean (± se) clutch and brood size was 2.83 ± 0.06 and 2.11 ± 0.07, respectively. Overall, 11.7% of nests failed between the egg and nestling stages, and the failure rate differed significantly between Fahal and the Daymaniyats, and across years. The mean proportion of eggs that hatched annually was 0.66 ± 0.02, and broods were significantly smaller on the Daymaniyats than on Fahal. Falcons on Fahal Island had a higher rate of hatching, a higher rate of nests that produced at least one chick, and produced more chicks per nest than on the Daymaniyats. We suggest that Fahal's proximity to the mainland gives breeding Sooty Falcons access to a more plentiful and stable source of food, especially during the period between arrival from the wintering grounds and the onset of the autumn migration of prey birds, resulting in the better reproductive rates for falcons on Fahal Island, relative to those on the Daymaniyat Islands. The annual asymptotic population growth rate (λ) was 0.87 (95% confidence interval (CI) 0.75–0.99), suggesting a declining population, although Sooty Falcons enjoyed a slightly higher population growth rate on Fahal than on the Daymaniyats. Because our study population is on the edge of the breeding range and is isolated from other breeding areas, measures to improve reproductive success of Sooty Falcons breeding on the islands in the Sea of Oman could be important for conservation of Sooty Falcons in Oman

Ecological Studies of the River Krishna near Gadwal, Telangana with Reference to Water Quality

Ecological studies in the river Krishna have been studies for a period of two years (May 2015 to April 2017). Physico-chemical and phycological aspects have been investigated to assess the quality of water. The water was well oxygenated with an alkaline pH, organic matter, chlorides and nutrients were recorded at low concentrations. Diatoms constituted the dominant group of algae. Multiple regression analysis was employed to discover the relative importance of various physico-chemical variables on the abundance and distribution of algae. Mathematical equations were derived involving the physico-chemical variables for better prediction of algal number

Phytotoxic effect of the extracts of Parthenium hysterophorus L. on the germination, seedling growth and biomass of some agricultural crops

This study was conducted to assess the phytotoxic effect of invasive species: Parthenium hysterophorus L. on the germination, seedling length and biomass of Zea mays, Macrotyloma uniflorum and Triticum aestivum, in order to explore its potential as noxious species. In this study, the allelopathic substances were extracted with distilled water and methanol from the aerial and underground part of P. hysterophorus L. in different concentration (1, 100, 150, 400 mg mL–1). The results of the study revealed that the methanol fraction of roots at 400 mg mL-1 concentration had the highest phytotoxic activity as compared to the double distilled water extract. Germination (%) was observed to be maximum (90%) for Z. mays with double distilled water above ground part extract at 1 mg mL-1 and lowest (10%) for M. uniflorum L. in 400 mg mL-1 both aerial and underground plant extracts at the last day of measurement. Mean shoot and root length were observed highest (17.6cm and 6.1cm respectively) in Z. mays with aerial double distilled water extract at 1 mg mL-1 concentration and it was found lowest (3.2cm and 2.8cm) in M. uniflorum with underground part double distilled water extract at 400 mg mL-1. Biomass was recorded highest (1.97 g/100cm2) in Z. mays in aerial part extract and lowest (0.83 g/100 cm2) in horse gram in underground part extract at concentration of 400mg mL–1 with double distilled water extract. In methanol, both aerial and underground part extracts, the germination observed only at 1mg mL-1 concentration

Optical and mid-infrared neon abundance determinations in star-forming regions

We have used observational spectroscopic data of star-forming regions compiled from the literature and photoionization models to analyse the neon ionic abundances obtained using both optical and mid-infrared emission lines. Comparing Ne++/H+ ionic abundances from distinct methods, we have found that, on average, the abundances obtained via infrared emission lines are higher than those obtained via optical lines, by a factor of 4. Photoionization models with abundance variations along the radius of the hypothetical nebula provide a possible explanation for a large part of the difference between ionic abundances via optical and infrared emission lines. The ionization correction factor (ICF) for the neon is obtained from direct determinations of ionic fractions using infrared emission lines. We derive a constant Ne/O ratio (log Ne/O ≈ -0.70) for a large range of metallicities, independently of the ICF used to compute the neon total abundance.Facultad de Ciencias Astronómicas y Geofísica

Strong radiative effect induced by clouds and smoke on forest net ecosystem productivity in central Siberia

Aerosols produced by wildfires are a common phenomenon in boreal regions. For the Siberian taiga, it is still an open question if the effects of aerosols on atmospheric conditions increase net CO2 uptake or photosynthesis. We investigated the factors controlling forest net ecosystem productivity (NEP) and explored how clouds and smoke modulate radiation as a major factor controlling NEP during fire events in the years 2012 and 2013. To characterize the underlying mechanisms of the NEP response to environmental drivers, Artificial Neural Networks (ANNs) were trained by eddy covariance flux measurements nearby the Zotino Tall Tower Observatory (ZOTTO). Total photosynthetically active radiation, vapour pressure deficit, and diffuse fraction explain at about 54-58% of NEP variability. NEP shows a strong negative sensitivity to VPD, and a small positive to f(dlf). A strong diffuse radiation fertilization effect does not exist at ZOTTO forest due to the combined effects of low light intensity, sparse canopy and low leaf area index. Results suggests that light intensity and canopy structure are important factors of the overall diffuse radiation fertilization effect.Peer reviewe