Physiological observations on a diatom Skeletonema costatum (Greville) Cleve

A chain-forming diatom Skeletonema costatum (Greville) Cleve collected from Yatsushiro Sea, Japan was cultured to determine the optimum level of some physico-chemical factors for their growth under laboratory conditions. Filtered and sterilized aged sea water enriched by adding nutrient solution (Provasoli 1968) was used as the culture medium. The plankton could tolerate a wide range of salinities (3-55 ppt). Optimum growth was observed at salinities of 20-35 ppt, temperatures of 20-25°C, light intensities of 80-120µE mˉ² secˉ¹ and pH between 7.5 and 8.0. Growth did not occur at salinities below 3 ppt and at temperatures above 30°C. From the present study, it is concluded that S. costatum was extremely euryhaline and tolerable to very low salinities

The influence of nitrogen and phosphorus on the growth of a diatom Skeletonema costatum (Greville) Cleve

Nitrogen and phosphorus requirements of a chain-forming diatom, Skeletonema costatum (Greville) Cleve, collected from Yatsushiro Sea, Japan, were investigated in a laboratory culture experiment. Sodium nitrate and sodium glycerophosphate were used as nitrogen and phosphorus sources, respectively. Cultures were grown in modified Provasoli's ASP2NTA medium (Provasoli et al. 1957) at 25±1°C, light intensity 60 µE mˉ² secˉ¹ and photoperiod 12:12-h, L:D cycle. Optimum growth was observed at nitrate concentrations of 3-10 mglˉ¹ and phosphate concentrations of 1.5-15 mglˉ¹. Adequate growth was also found at the nitrate concentration of up to as high as 300 mglˉ¹. Significantly poorer growth was found at lower nitrate (15 mglˉ¹) concentrations. From the present study, it is concluded that S. costatum can grow well at wide ranges of nitrate concentrations but is sensitive to higher phosphate concentrations

The Hyper Suprime-Cam SSP Survey: Overview and Survey Design

Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2m Subaru telescope on the summit of Maunakea in Hawaii. A team of scientists from Japan, Taiwan and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg$^2$ in five broad bands ($grizy$), with a $5\,\sigma$ point-source depth of $r \approx 26$. The Deep layer covers a total of 26~deg$^2$ in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg$^2$). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey.Comment: 14 pages, 7 figures, 5 tables. Corrected for a typo in the coordinates of HSC-Wide spring equatorial field in Table

Role of PACAP and VIP Signalling in Regulation of Chondrogenesis and Osteogenesis

Pituitary adenylate cyclase activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are multifunctional proteins that can regulate diverse physiological processes. These are also regarded as neurotrophic and anti-inflammatory substances in the CNS, and PACAP is reported to prevent harmful effects of oxidative stress. In the last decade more and more data accumulated on the similar function of PACAP in various tissues, but its cartilage- and bone-related presence and functions have not been widely investigated yet. In this summary we plan to verify the presence and function of PACAP and VIP signalling tool kit during cartilage differentiation and bone formation. We give evidence about the protective function of PACAP in cartilage regeneration with oxidative or mechanically stress and also with the modulation of PACAP signalling in vitro in osteogenic cells. Our observations imply the therapeutic perspective that PACAP might be applicable as a natural agent exerting protecting effect during joint inflammation and/or may promote cartilage regeneration during degenerative diseases of articular cartilage

Tip of the iceberg: overmassive black holes at 4<z<7 found by JWST are not inconsistent with the local MBH\mathcal{M}_{\rm BH}-M⋆\mathcal{M}_\star relation

JWST is revealing a new remarkable population of high-redshift ($z\gtrsim4$), low-luminosity Active Galactic Nuclei (AGNs) in deep surveys and detecting the host galaxy stellar light in the most luminous and massive quasars at $z\sim 6$ for the first time. Latest results claim supermassive black holes (SMBHs) in these systems to be significantly more massive than expected from the local BH mass - stellar mass ($\mathcal{M}_{\rm BH} - \mathcal{M}_\star$) relation and that this is not due to sample selection effects. Through detailed statistical modeling, we demonstrate that the coupled effects of selection biases (i.e., finite detection limit and requirements on detecting broad lines) and measurement uncertainties in $\mathcal{M}_{\rm BH}$ and $\mathcal{M}_\star$ can in fact largely account for the reported offset and flattening in the observed $\mathcal{M}_{\rm BH} - \mathcal{M}_\star$ relation toward the upper envelope of the local relation, even for those at $\mathcal{M}_{\rm BH} < 10^8\,M_{\odot}$. We further investigate the possible evolution of the $\mathcal{M}_{\rm BH} - \mathcal{M}_\star$ relation at $z\gtrsim 4$ with careful treatment of observational biases and consideration of the degeneracy between intrinsic evolution and dispersion in this relation. The bias-corrected intrinsic $\mathcal{M}_{\rm BH} - \mathcal{M}_\star$ relation in the low-mass regime suggests that there might be a large population of low-mass BHs (${\rm log}\,\mathcal{M}_{\rm BH} \lesssim 5$), possibly originating from lighter seeds, remaining undetected or unidentified even in the deepest JWST surveys. These results have important consequences for JWST studies of BH seeding and the coevolution between SMBHs and their host galaxies at the earliest cosmic times.Comment: 21 pages, 9 figures, submitted to Ap

XQR-30: Black hole masses and accretion rates of 42 Z 6 quasars

We present bolometric luminosities, black hole masses, and Eddington ratios for 42 luminous quasars at z? 6 using high signal-to-noise ratio VLT/X-shooter spectra, acquired as part of the enlarged ESO Large Programme XQR-30. In particular, we derived the bolometric luminosities from the rest-frame 3000 luminosities using a bolometric correction from the literature, as well as the black hole masses by modeling the spectral regions around the C?IV 1549 and the Mg?II 2798 emission lines, with scaling relations calibrated in the Local Universe. We find that the black hole masses derived from both emission lines are in the same range and the scatter of the measurements agrees with expectations from the scaling relations. The Mg?II-derived masses are between ~(0.8-12) 109 M? and the derived Eddington ratios are within ~0.13-1.73, with a mean (median) of 0.84(0.72). By comparing the total sample of quasars at z&gt; 5.8, from this work and from the literature, to a bolometric luminosity distribution-matched sample at z~ 1.5, we find that quasars at high redshift host slightly less massive black holes, which accrete slightly more rapidly than those at lower z, with a difference in the mean Eddington ratios of the two samples of ~0.27. These findings are in agreement with the results of recent works in the literature

XQR-30: Black Hole Masses and Accretion Rates of 42 z>6 Quasars

We present bolometric luminosities, black hole masses and Eddington ratios for 42 luminous quasars at z>6 using high signal-to-noise ratio VLT/X-Shooter spectra, acquired in the enlarged ESO Large Programme XQR-30. In particular, we derive bolometric luminosities from the rest-frame 3000 A, luminosities using a bolometric correction from the literature, and the black hole masses by modelling the spectral regions around the CIV 1549A and the MgII 2798A emission lines, with scaling relations calibrated in the local universe. We find that the black hole masses derived from both emission lines are in the same range, and the scatter of the measurements agrees with expectations from the scaling relations. The MgII-derived masses are between ~(0.8-12) x 10^9 Msun, and the derived Eddington ratios are within ~0.13-1.73, with a mean (median) of 0.84 (0.72). By comparing the total sample of quasars at z>5.8, from this work and from the literature, to a bolometric luminosity distribution-matched sample at z~1.5, we find that quasars at high redshift host slightly less massive black holes which accrete slightly more rapidly than at lower-z, with a difference in the mean Eddington ratios of the two samples of ~0.27, in agreement with recent literature work.Comment: 9 pages; 5 figures; accepted for publication in A&