The Long-Term Experiment Platform for the Study of Agronomical and Environmental Effects of the Biochar: Methodological Framework

In this communication, a wide overview of historical Long-Term Experimental Platforms (LTEP) regarding changes in soil organic matter is presented for the purpose of networking, data sharing, experience sharing and the coordinated design of experiments in the area of Earth system science. This serves to introduce a specific platform of experiments regarding biochar application to soil (LTEP-BIOCHAR) and its use for agronomic and environmental purposes (e.g., carbon sequestration, soil erosion, soil biodiversity) in real conditions and over a significative timeframe for pedosphere dynamics. The methodological framework, including the goals, geographical scope and eligibility rules of such a new platform, is discussed. Currently, the LTEP-BIOCHAR is the first of its kind, a community-driven resource dedicated to biochar, and displays around 20 long-term experiments from Europe, the Middle East and Africa. The selected field experiments take place under dynamically, meteorologically and biologically different conditions. The purposes of the platform are (1) listing the field experiments that are currently active, (2) uncovering methodological gaps in the current experiments and allowing specific metadata analysis, (3) suggesting the testing of new hypotheses without unnecessary duplications while establishing a minimum standard of analysis and methods to make experiments comparable, (4) creating a network of expert researchers working on the agronomical and environmental effects of biochar, (5) supporting the design of coordinated experiments and (6) promoting the platform at a wider international level

DNA HLA-DRB1 analysis in children of positive mothers and estimated risk of vertical HIV transmission.

RFLP HLA-DRB I analysis was performed on a total of 83 children born from HIV -infected mothers, 35 of whom were shown to be HIV -infected, while 48 reverted from seropositivity to seronegativity, indicating that they were not infected. Moreover, 89 healthy children were used as controls. It has been found that DRBI-14a and DRBI-13a.4 alleles were not present in the HIV-infected children, but were found in the sero-reverted (HIV-uninfected) children (in the proportion of 9·6 per cent and 5·3 per cent, respectively), and in the controls (5·6 per cent and 3·9 per cent, respectively). The possible correlation between DR and risk of HIV transmission from mother to baby was analysed considering every single allele, estimated by the ratio between the number of infected children and the number of all children born from seropositive mothers. There was also introduced a statisticGfor the control of 'statistical validity' of data

Short-Term Bisphosphonate Therapy Could Ameliorate Osteonecrosis: A Complication in Childhood Hematologic Malignancies

Osteonecrosis (ON) is a critical complication in the treatment of childhood leukemia and lymphoma. It particularly affects survivors of acute lymphoblastic leukemia and non-Hodgkin lymphoma reflecting the cumulative exposure to glucocorticosteroid therapy. ON is often multiarticular and bilateral, specially affecting weight-bearing joints. A conventional approach suggests a surgical intervention even if pharmacological options have also recently been investigated. We reported two cases of long time steroid-treated patients who underwent Bone Marrow Transplantation (BMT) for hematological disease. Both patients developed femoral head osteonecrosis (ON) that was diagnosed by magnetic resonance imaging (MRI) and the ON was also accompanied with pain and a limp. Despite of the conventional strategies of therapy, we successfully started a short-term treatment with bisphosphonates in order to decrease the pain and the risk of fracture

A Near-Infrared Stellar Census of the Blue Compact Dwarf Galaxy VII~Zw~403

We present near-infrared single-star photometry for the low-metallicity Blue Compact Dwarf galaxy VII~Zw~403. We achieve limiting magnitudes of F110W~$\approx$~25.5 and F160W~$\approx$~24.5 using one of the NICMOS cameras with the HST equivalents of the ground-based J and H filters. The data have a high photometric precision (0.1 mag) and are $>95$% complete down to magnitudes of about 23, far deeper than previous ground-based studies in the near-IR. The color-magnitude diagram contains about 1000 point sources. We provide a preliminary transformation of the near-IR photometry into the ground system...Comment: Accepted for publication by the AJ, preprint has 49 pages, 2 tables, and 16 figure

The Age of Cluster Galaxies from Continuum Colors

We determine the age of 1,104 early-type galaxies in eight rich clusters ($z = 0.0046$ to $0.175$) using a new continuum color technique. We find that galaxies in clusters divide into two populations, an old population with a mean age similar to the age of the Universe (12 Gyrs) and a younger population with a mean age of 9 Gyrs. The older population follows the expected relations for mass and metallicity that imply a classic monolithic collapse origin. Although total galaxy metallicity is correlated with galaxy mass, it is uncorrelated with age. It is impossible, with the current data, to distinguish between a later epoch of star formation, longer duration of star formation or late bursts of star formation to explain the difference between the old and young populations. However, the global properties of this younger population are correlated with cluster environmental factors, which implies secondary processes, post-formation epoch, operate on the internal stellar population of a significant fraction of cluster galaxies. In addition, the mean age of the oldest galaxies in a cluster are correlated with cluster velocity dispersion implying that galaxy formation in massive clusters begins at earlier epochs than less massive clusters.Comment: 35 pages, 10 figures, accepted by Ap

Iron as a tracer in galaxy clusters and groups

Available X-ray data are collected and organized concerning the iron and gas content of galaxy clusters and groups, together with the optical luminosity, mass and iron abundance of cluster galaxies. Several astrophysical inferences are then drawn, including the evidence for rich clusters having evolved without much baryon exchange with their surrondings, and having experienced very similar star formation histories. Groups are much gas-poor compared to clusters, and appear instead to have shed a major fraction of their original cosmic share of baryons, which indicates that galaxy clusters cannot have formed by assembling groups similar to the present day ones. It is argued that this favors low-$\Omega$ universes, in which the growth of rich clusters is virtually complete at high redshifts. It is also argued that elemental abundance ratios in clusters are nearly solar, which is consistent with a similar proportion of supernovae of Type Ia and Type II having enriched both the solar neghborhood as well clusters as a whole. Much of the iron in clusters appears to reside in the intracluster medium rather than inside galaxies. It appears that the baryon to star conversion in clusters has been nearly as efficient as currently adopted for the universe as a whole. Yet the metallicity of the clusters is $\sim 5$ times higher than the global metallicity adopted for the nearby universe. It is concluded that the intergalactic medium should have a metallicity $\sim 1/3$ solar if stellar nucleosynthesis has proceeded in stars within field galaxies with the same efficiency as in stars within clusters of galaxies.Comment: AASTex Latex, 29 pages, 6 figure

Cluster vs. Field Elliptical Galaxies and Clues on their Formation

Using new observations for a sample of 931 early-type galaxies we investigate whether the \mg2--\so relation shows any dependence on the local environment. The galaxies have been assigned to three different environments depending on the local overdensity: clusters, groups, and field, having used our completeredshift database to guide the assignment of galaxies. It is found that cluster, group and field early-type galaxies follow almost identical \mg2--\so\ relations, with the largest \mg2 zero-point difference (clusters minus field) being only $0.007\pm 0.002$ mag. No correlation of the residuals is found with the morphological type or the bulge to disk ratio. Using stellar population models in a differential fashion, this small zero-point difference implies a luminosity-weighted age difference of only $\sim 1$ Gyr between the corresponding stellar populations, with field galaxies being younger. The mass-weighted age difference could be significantly smaller, if minor events of late star formation took place preferentially in field galaxies. We combine these results with the existing evidence for the bulk of stars in cluster early-type galaxies having formed at very high redshift, and conclude that the bulk of stars in galactic spheroids had to form at high redshifts (z\gsim 3), no matter whether such spheroids now reside in low or high density regions. The cosmological implications of these findings are briefly discussed.Comment: 16 pages, 2 figures, accepted for publication in the ApJ.

Fundamental Strings, Holography, and Nonlinear Superconformal Algebras

We discuss aspects of holography in the AdS_3 \times S^p near string geometry of a collection of straight fundamental heterotic strings. We use anomalies and symmetries to determine general features of the dual CFT. The symmetries suggest the appearance of nonlinear superconformal algebras, and we show how these arise in the framework of holographic renormalization methods. The nonlinear algebras imply intricate formulas for the central charge, and we show that in the bulk these correspond to an infinite series of quantum gravity corrections. We also makes some comments on the worldsheet sigma-model for strings on AdS_3\times S^2, which is the holographic dual geometry of parallel heterotic strings in five dimensions.Comment: 25 page

On the fraction of intermediate-mass close binaries that explode as type-Ia supernovae

Type-Ia supernovae (SNe-Ia) are thought to result from a thermonuclear runaway in white dwarfs (WDs) that approach the Chandrasekhar limit, either through accretion from a companion or a merger with another WD. I compile observational estimates of the fraction eta of intermediate-mass stars that eventually explode as SNe-Ia, supplement them with several new estimates, and compare them self-consistently. The estimates are based on five different methods, each utilising some observable related to the SN-Ia rate, combined with assumptions regarding the IMF: the ratio of SN-Ia to core-collapse rates in star-forming galaxies; the SN-Ia rate per unit star-formation rate; the SN-Ia rate per unit stellar mass; the iron to stellar mass ratio in galaxy clusters; and the abundance ratios in galaxy clusters. The five methods indicate that a fraction in the range eta~2-40% of all stars with initial masses of 3-8 M_sun (the generally assumed SN-Ia progenitors) explode as SNe-Ia. A fraction of eta~15% is consistent with all five methods for a range of plausible IMFs. Considering also the binarity fraction among such stars, the mass ratio distribution, the separation distribution, and duplicity (every binary can produce only one SN-Ia explosion), this implies that nearly every intermediate mass close binary ends up as a SN-Ia, or possibly more SNe-Ia than progenitor systems. Theoretically expected fractions are generally one to two orders of magnitude lower. The problem could be solved: if all the observational estimates are in error; or with a ``middle-heavy'' IMF; or by some mechanism that strongly enhances the efficiency of binary evolution toward SN-Ia explosion; or by a non-binary origin for SNe-Ia.Comment: MNRAS, accepted versio

The epochs of early-type galaxy formation as a function of environment

The aim of this paper is to set constraints of the epochs of early-type galaxy formation through the 'archaeology' of the stellar populations in local galaxies. Using our models of absorption line indices that account for variable abundance ratios, we derive the stellar population parameters of 124 early-type galaxies in high and low density environments. We find that all three parameters age, metallicity, and alpha/Fe ratio are correlated with velocity dispersion. We further find evidence for an influence of the environment on the stellar population properties. Massive early-type galaxies in low-density environments appear on average ~2 Gyrs younger and slightly more metal-rich than their counterparts in high density environments. No offsets in the alpha/Fe ratios, instead, are detected. We translate the derived ages and alpha/Fe ratios into star formation histories. We show that most star formation activity in early-type galaxies is expected to have happened between redshifts 3 and 5 in high density and between redshifts 1 and 2 in low density environments. We conclude that at least 50 per cent of the total stellar mass density must have already formed at z 1, in good agreement with observational estimates of the total stellar mass density as a function of redshift. Our results suggest that significant mass growth in the early-type galaxy population below z 1 must be restricted to less massive objects, and a significant increase of the stellar mass density between redshifts 1 and 2 should be present caused mainly by the field galaxy population. The results of this paper further imply vigorous star formation episodes in massive objects at z 2-5 and the presence of evolved ellipticals around z 1, both observationally identified as SCUBA galaxies and EROs.Comment: 20 pages, 10 figures, plus appendix, accepted by Ap