Broadband Optical and Infrared Observations of Seyfert Galaxies

Broadband observations between 0.3 and 3.4 μ are reported for II bright Seyfert galaxies. The ultraviolet and two micron fluxes of NGC 4151 have both increased by ∼ 0.3 mag between 1970 and 1971. 3C 120 was constant to within about ± 0.1 mag in the infrared during a period when it varied in the optical by ∼ 0.8 mag. Comparison with published data suggests NGC 4051 is an optical variable. The spatial distribution of the emitted flux shortward of 2.2 μ suggests that the emission from Seyfert galaxies can be decomposed into a nuclear source showing ultraviolet and infrared excesses and an extended source with normal starlike colours. The U–B and B–V colours fall on the two-colour diagram in positions consistent with a mixture of light from sources with galaxy-like and quasar-like colours and can be used to derive the ratio of the light from the nuclear source to that from the surrounding galaxy. This ratio is used to separate the contributions of nuclear source and galaxy in the infrared. The infrared spectrum of the nuclear source in NGC 1068 is steeper than that in the other Seyfert galaxies and more closely resembles that of non-Seyfert infrared galaxies such as M82 and NGC 253 rather than that of quasars. A wide range exists in the proportion of blue light contributed by the nuclear sources but the (B–[2.2 μ])₀ colours of the combined emission range only by ± 0.3 mag implying large differences exist in the (B–[2.2 μ])₀ of the nuclear source alone, in contrast to the homogeneity of the purely optical colours

Broadband Optical and Infrared Observations of Seyfert Galaxies

Broadband observations between 0.3 and 3.4 μ are reported for II bright Seyfert galaxies. The ultraviolet and two micron fluxes of NGC 4151 have both increased by ∼ 0.3 mag between 1970 and 1971. 3C 120 was constant to within about ± 0.1 mag in the infrared during a period when it varied in the optical by ∼ 0.8 mag. Comparison with published data suggests NGC 4051 is an optical variable. The spatial distribution of the emitted flux shortward of 2.2 μ suggests that the emission from Seyfert galaxies can be decomposed into a nuclear source showing ultraviolet and infrared excesses and an extended source with normal starlike colours. The U–B and B–V colours fall on the two-colour diagram in positions consistent with a mixture of light from sources with galaxy-like and quasar-like colours and can be used to derive the ratio of the light from the nuclear source to that from the surrounding galaxy. This ratio is used to separate the contributions of nuclear source and galaxy in the infrared. The infrared spectrum of the nuclear source in NGC 1068 is steeper than that in the other Seyfert galaxies and more closely resembles that of non-Seyfert infrared galaxies such as M82 and NGC 253 rather than that of quasars. A wide range exists in the proportion of blue light contributed by the nuclear sources but the (B–[2.2 μ])₀ colours of the combined emission range only by ± 0.3 mag implying large differences exist in the (B–[2.2 μ])₀ of the nuclear source alone, in contrast to the homogeneity of the purely optical colours

Optical Monitoring of 3C 390.3 from 1995 to 2004 and Possible Periodicities in the Historical Light Curve

We report V, R, and I band CCD photometry of the radio galaxy 3C 390.3 obtained with the 1.56-m telescope of the Shanghai Astronomical Observatory from March 1995 to August 2004. Combining these data with data from the literature, we have constructed a historical light curve from 1894 to 2004 and searched for periodicities using the CLEANest program. We find possible periods of 8.30+-1.17, 5.37+-0.49, 3.51+-0.21, and 2.13+-0.08 years.Comment: Accepted by AJ, 34 pages, 11 figure

Regional Satellite Algorithms to Estimate Chlorophyll-a and Total Suspended Matter Concentrations in Vembanad Lake

This is the final version. Available on open access from MDPI via the DOI in this recordData Availability Statement: Data available with the corresponding author. Would be shared on request.A growing coastal population is leading to increased anthropogenic pollution that greatly affects coastal and inland water bodies, especially in the tropics. The Sustainable Development Goal-14, ‘Life below water’ emphasises the importance of conservation and sustainable use of the ocean and its resources. Pollution management practices often include monitoring of water quality using in situ observations of chlorophyll-a (chl-a) and total suspended matter (TSM). Satellite technology, including the MultiSpectral Instrument (MSI) sensor onboard Sentinel-2, enables the continuous monitoring of these variables in inland waters at high spatial and temporal resolutions. To improve the monitoring of water quality in the tropical Vembanad-Kol-Wetland (VKW) system, situated on the southwest coast of India, we present two regionally tuned satellite algorithms developed to estimate chl-a and TSM concentrations. The new algorithms estimate the chl-a and TSM concentrations from the simulated reflectance values as a function of the inherent optical properties using a forward modelling approach. The model was parameterised using the National Aeronautics and Space Administration (NASA) bio-Optical Marine Algorithm Dataset (NOMAD) and in situ measurements collected in the VKW system. To assess model performance, results were compared with in situ measurements of chl-a and TSM and other existing satellite-based models of chl-a and TSM. For satellite application, two different atmospheric correction methods (ACOLITE and POLYMER) were tested and satellite matchups were used to validate the new chl-a and TSM algorithms following standard validation procedures. The results demonstrated that the new algorithms were in good agreement with in situ observations and outperform existing chl-a and TSM algorithms. The new regional satellite algorithms can be used to monitor water quality within the VKW system to support the sustainable management under natural (cyclones, floods, rainfall, and tsunami) and anthropogenic pressures (industrial effluents, agricultural practices, recreational activities, construction, and demolishing concrete structures) and help achieve Sustainable Development Goal 14.Natural Environment Research Council (NERC)Department of Science and Technology, IndiaEuropean Space AgencyUKR

Intermediate resolution H-beta spectroscopy and photometric monitoring of 3C 390.3 I. Further evidence of a nuclear accretion disk

We have monitored the AGN 3C390.3 between 1995 and 2000.Two large amplitude outbursts, of different duration, in continuum and H beta light were observed ie.: in October 1994 a brighter flare that lasted about 1000 days and in July 1997 another one that lasted about 700 days were detected. The flux in the H beta wings and line core vary simultaneously, a behavior indicative of predominantly circular motions in the BLR.Important changes of the Hbeta emission profiles were detected: at times, we found profiles with prominent asymmetric wings, as those normaly seen in Sy1s, while at other times, we observe profiles with weak almost symmetrical wings, similar to those seen in Sy1.8s. We found that the radial velocity difference between the red and blue bumps is anticorrelated with the light curves of H beta and continuum radiation.e found that the radial velocity difference between the red and blue bumps is anticorrelated with the light curves of H-beta and continuum radiation. Theoretical H-beta profiles were computed for an accretion disk, the observed profiles are best reproduced by an inclined disk (25 deg) whose region of maximum emission is located roughly at 200 Rg. The mass of the black hole in 3C 390.3, estimated from the reverberation analysis is Mrev = 2.1 x 10^9 Msun, ie. 5 times larger than previous estimatesComment: 18 pages, 13 figures, 4 tables. to appear in Astronomy and Astrophysic

Global variability and controls on the accumulation of fallout radionuclides in cryoconite

The accumulation of fallout radionuclides (FRNs) from nuclear weapons testing and nuclear accidents has been evaluated for over half a century in natural environments; however, until recently their distribution and abundance within glaciers have been poorly understood. Following a series of individual studies of FRNs, specifically 137Cs, 241Am and 210Pb, deposited on the surface of glaciers, we now understand that cryoconite, a material commonly found in the supraglacial environment, is a highly efficient accumulator of FRNs, both artificial and natural. However, the variability of FRN activity concentrations in cryoconite across the global cryosphere has never been assessed. This study thus aims to both synthesize current knowledge on FRNs in cryoconite and assess the controls on variability of activity concentrations. We present a global database of new and previously published data based on gamma spectrometry of cryoconite and proglacial sediments, and assess the extent to which a suite of environmental and physical factors can explain spatial variability in FRN activity concentrations in cryoconite. We show that FRNs are not only found in cryoconite on glaciers within close proximity to specific sources of radioactivity, but across the global cryosphere, and at activity concentrations up to three orders of magnitude higher than those found in soils and sediments in the surrounding environment. We also show that the organic content of cryoconite exerts a strong control on accumulation of FRNs, and that activity concentrations in cryoconite are some of the highest ever described in environmental matrices outside of nuclear exclusion zones, occasionally in excess of 10,000 Bq kg−1. These findings highlight a need for significant improvements in the understanding of the fate of legacy contaminants within glaciated catchments. Future interdisciplinary research is required on the mechanisms governing their accumulation, storage, and mobility, and their potential to create time-dependent impacts on downstream water quality and ecosystem sustainability

Extensive retreat of Greenland tidewater glaciers 2000-2010

Overall mass loss from the Greenland ice sheet nearly doubled during the early 2000s resulting in an increased contribution to sea-level rise, with this step-change being mainly attributed to the widespread frontal retreat and accompanying dynamic thinning of tidewater glaciers. Changes in glacier calving-front positions are easily derived from remotely sensed imagery and provide a record of dynamic change. However, ice-sheet-wide studies of calving fronts have been either spatially or temporally limited. In this study multiple calving-front positions were derived for 199 Greenland marine-terminating outlet glaciers with width greater than 1 km using Landsat imagery for the 11-year period 2000–2010 in order to identify regional seasonal and inter-annual variations. During this period, outlet glaciers were characterized by sustained and substantial retreat summing to more than 267 km, with only 11 glaciers showing overall advance. In general, the pattern of mass loss detected by GRACE (Gravity Recovery and Climate Experiment) and other measurements is reflected in the calving record of Greenland glaciers. Our results suggest several regions in the south and east of the ice sheet likely share controls on their dynamic changes, but no simple single control is apparent

The clinical use of memantine

This review outlines the use of memantine in clinical practice and represents the output of a consensus group who met to consider the use of the drug. The main conclusions were: memantine, a glutamatergic agent, has a different mode of action to the other available agents, for the treatment of Alzheimer's disease, the anticholinesterases; is indicated for the treatment of moderately severe to severe Alzheimer's disease; shows efficacy over placebo in improving cognitive function, activities of daily living and global assessments; is well tolerated with a favourable side effect profile (the main side effects are hallucinations, confusion, dizziness, headache and tiredness) and; can be combined with good efficacy and safety with donepezil. Memantine looks likely to prove a valuable new tool in clinical practice