Relativistic and Newtonian core-shell models: analytical and numerical results

We make a detailed analysis of Newtonian as well as relativistic core-shell models recently proposed to describe a black hole or neutron star surrounded by shells of matter, and in a seminal sense also galaxies, supernovae and star remnants since there are massive shell-like structures surrounding many of them and also evidences for many galactic nuclei hiding black holes. We discuss the unicity of the models in relation to their analyticity at the black hole horizon and also to the full elimination of conical singularities. Secondly, we study the role played by the presence/lack of discrete reflection symmetries about equatorial planes in the chaotic behavior of the orbits, which is to be contrasted with the almost universal acceptance of reflection symmetries as default assumptions in galactic modeling. We also compare the related effects if we change a true central black hole by a Newtonian central mass. The numerical findings are: 1- The breakdown of the reflection symmetry about the equatorial plane in both Newtonian and relativistic core-shell models does i) enhance in a significant way the chaoticity of orbits in reflection symmetric oblate shell models and ii) inhibit significantly also the occurrence of chaos in reflection symmetric prolate shell models. In particular, in the prolate case the lack of the reflection symmetry provides the phase space with a robust family of regular orbits that is otherwise not found at higher energies. 2- The relative extents of the chaotic regions in the relativistic cases (i. e. with a true central black hole) are significantly larger than in the corresponding Newtonian ones (which have just a $-1/r$ central potential).Comment: AASTEX, 22 pages plus 28 postscript figures, to appear in Ap.

Alley coppice: an innovative land use system - options of system design with experimental evidence

Agroforestry and Short Rotation Coppice (SRC), for timber and bioenergy wood production, are recognized as economically viable and sustainable as separate cropping systems under ideal growing conditions. Little is known about agricultural and ecological interactions which might occur combining them in a tree-based intercropping system. This mixed approach, called alley coppice, is currently investigated in an European research Project (www.agrocop.com), and has important advantages: (i) a regular income guaranteed from the SRC component; (ii) light competition between species can often improve the stem form of timber trees; (iii) timber trees can be planted at the final spacing, avoiding expensive thinning; (iv) SRC component protects young timber trees from wind/storm damage; (v) alley coppice is expected to have positive impacts on biodiversity, and reducing soil erosion. Three system designs are currently investigated: Simultaneous planting (SP); Lagged planting (LP) and Border planting (BP). In SP, timber and SRC components are planted in the same year; the key investigated factor is the distance between timber trees and the first SRC row, comparing 1, 2, 3 m in plantations in Ireland, Germany and Italy. A tree row width of three meters guaranteed satisfying growth rates of Sorbus and Pyrus timber trees in a mixture with 2-yr SRC poplar (Populus spp) in Italy, improving timber wood quality. LP, with planting SRC under adult timber trees, is studied in France and Ireland, according to timber tree age, species and inter-row spacings. In France, light and water competition had significant effects on poplar SRC growth and yield according to the distance from the walnut trees. BP involves planting timber trees along the borders of SRC blocks. Experimental plantations were established in Ireland and Germany, with the aim of avoiding asymmetric light competition that might hamper stem form of timber trees. Guidelines for practitioners on alley coppice optimization will be provided at the end of the project

Constraints on the kinematics of the 44Ti ejecta of Cassiopeia A from INTEGRAL/SPI

The medium-lived 44Ti isotope is synthesised by explosive Si-burning in core-collapse supernovae. It is extremely sensitive to the dynamics of the explosion and therefore can be used to indirectly probe the explosion scenario. The young supernova remnant Cassiopeia A is to date the only source of gamma-ray lines from 44Ti decay. The emission flux has been measured by CGRO/COMPTEL, BeppoSAX/PDS and INTEGRAL/IBIS. The high-resolution spectrometer SPI on-board the INTEGRAL satellite can provide spectrometric information about the emission. The line profiles reflect the kinematics of the 44Ti in Cassiopeia A and can thus place constraints on its nucleosynthesis and potentially on the associated explosion process. Using 4 years of data from INTEGRAL/SPI, we have searched for the gamma-ray signatures from the decay of the 44Ti isotope. The overwhelming instrumental background noise required an accurate modelling and a solid assessment of the systematic errors in the analysis. Due to the strong variability of the instrumental background noise, it has not been possible to extract the two lines at 67.9 and 78.4keV. Regarding the high-energy line at 1157.0keV, no significant signal is seen in the 1140-1170keV band, thereby suggesting that the line signal from Cassiopeia A is broadened by the Doppler effect. From our spectrum, we derive a ~ 500km/s lower limit at 2sigma on the expansion velocity of the 44Ti ejecta. Our result does not allow us to constrain the location of 44Ti since the velocities involved throughout the remnant, derived from optical and X-ray studies, are all far above our lower limit.Comment: 7 pages, 8 figures, published in A&

An active vesicle priming machinery suppresses axon regeneration upon adult CNS injury

Axons in the adult mammalian central nervous system fail to regenerate after spinal cord injury. Neurons lose their capacity to regenerate during development, but the intracellular processes underlying this loss are unclear. We found that critical components of the presynaptic active zone prevent axon regeneration in adult mice. Transcriptomic analysis combined with live-cell imaging revealed that adult primary sensory neurons downregulate molecular constituents of the synapse as they acquire the ability to rapidly grow their axons. Pharmacogenetic reduction of neuronal excitability stimulated axon regeneration after adult spinal cord injury. Genetic gain- and loss-of-function experiments uncovered that essential synaptic vesicle priming proteins of the presynaptic active zone, but not clostridial-toxin-sensitive VAMP-family SNARE proteins, inhibit axon regeneration. Systemic administration of Baclofen reduced voltage-dependent Ca2+ influx in primary sensory neurons and promoted their regeneration after spinal cord injury. These findings indicate that functional presynaptic active zones constitute a major barrier to axon regeneration

Tracing the evolution of nearby early-type galaxies in low density environments. The Ultraviolet view from GALEX

We detected recent star formation in nearby early-type galaxies located in low density environments, with GALEX Ultraviolet (UV) imaging. Signatures of star formation may be present in the nucleus and in outer rings/arm like structures. Our study suggests that such star formation may be induced by different triggering mechanisms, such as the inner secular evolution driven by bars, and minor accretion phenomena. We investigate the nature of the (FUV-NUV) color vs. Mg2 correlation, and suggest that it relates to "downsizing" in galaxy formation.Comment: Conference "UV Universe 2010" S. Petersburg 31 May - 3 June, 2010 Accepted for publication in Astrophysics & Space Science . The final publication is available at http://www.springerlink.co

AGFORWARD Project Final Report

Executive summary: The AGFORWARD project (Grant Agreement N° 613520) had the overall goal to promote agroforestry practices in Europe that will advance sustainable rural development. It had four objectives (described below) which address 1) the context and extent of agroforestry in Europe, 2) identifying, developing and field-testing agroforestry innovations through participatory networks, 3) evaluating innovative designs and practices at field-, farm-, and landscape-scales, and promoting agroforestry in Europe through policy development and dissemination. Agroforestry is defined as the practice of deliberately integrating woody vegetation (trees or shrubs) with crop and/or animal systems to benefit from the resulting ecological and economic interactions. Context: European agroforestry has been estimated to cover 10.6 Mha (using a literature review) and 15.4 Mha using the pan-European LUCAS dataset (i.e. 8.8% of the utilised agricultural area). Livestock agroforestry (15.1 Mha) is, by far, the dominant type of agroforestry. The LUCAS analysis provides a uniform method to compare agroforestry areas between countries and over time. Identify, develop and field-test agroforestry innovations: 40 stakeholder groups (involving about 820 stakeholders across 13 European countries) developed and field-tested agroforestry innovations which have been reported in 40 “lesson learnt” reports, and in a user-friendly format in 46 “Agroforestry innovation leaflets”. The innovations for agroforestry systems of high nature and cultural value included cheaper methods of tree protection and guidance for establishing legumes in wood pastures. Innovations for agroforestry with timber plantations, olive groves and apple orchards include the use of medicinal plants and reduction of mowing costs. Innovations for integrating trees on arable farms included assessments of yield benefits by providing wind protection. Innovations for livestock farms included using trees to enhance animal welfare, shade protection, and as a source of fodder. Peer-reviewed journal papers and conference presentations on these and other related topics were developed. Evaluation of agroforestry designs and practices at field- and landscape-scale: a range of publicly available field-scale analysis tools are available on the AGFORWARD website. These include the “CliPick” climate database, and web-applications of the Farm-SAFE and Hi-sAFe model. The results of field- and landscape-scale analysis, written up as peer-reviewed papers, highlight the benefits of agroforestry (relative to agriculture) for biodiversity enhancement and providing regulating ecosystem services, such as for climate and water regulation and purification. Policy development and dissemination: detailed reviews of existing policy and recommendations for future European agroforestry policy have been produced. The support provided is far wider than the single specified agroforestry measures. The recommendations included the collation of existing measures, and that agroforestry systems should not forfeit Pillar I payments. Opportunities for farmlevel and landscape-level measures were also identified. The project results can be found on the project website (www.agforward.eu), a Facebook account (www.facebook.com/AgforwardProject), a Twitter account (https://twitter.com/AGFORWARD_EU), and a quarterly electronic newsletter (http://www.agforward.eu/index.php/en/newsletters-1514.html). The number of national associations in Europe was extended to twelve, and a web-based training resource on agroforestry (http://train.agforward.eu/language/en/agforall/) created. AGFORWARD also supported the Third European Agroforestry Conference in Montpellier in 2016 attracting 287 delegates from 26 countries including many farmers. We also initiated another 21 national conferences or conference sessions on agroforestry, made about 240 oral presentations, 61 poster presentations, produced about 50 news articles, and supported about 87 workshop, training or field-visit activities (in addition to the stakeholder groups)

Prevalence of SARS-CoV-2 in Household Members and Other Close Contacts of COVID-19 Cases: A Serologic Study in Canton of Vaud, Switzerland.

Research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission within households and other close settings using serological testing is scarce. We invited coronavirus disease 2019 (COVID-19) cases diagnosed between February 27 and April 1, 2020, in Canton of Vaud, Switzerland, to participate, along with household members and other close contacts. Anti-SARS-CoV-2 immunoglobulin G antibodies were measured using a Luminex immunoassay. We estimated factors associated with serological status using generalized estimating equations. Overall, 219 cases, 302 household members, and 69 other close contacts participated between May 4 and June 27, 2020. More than half of household members (57.2%; 95% CI, 49.7%-64.3%) had developed a serologic response to SARS-CoV-2, while 19.0% (95% CI, 10.0%-33.2%) of other close contacts were seropositive. After adjusting for individual and household characteristics, infection risk was higher in household members aged ≥65 years than in younger adults (adjusted odds ratio [aOR], 3.63; 95% CI, 1.05-12.60) and in those not strictly adhering to simple hygiene rules like hand washing (aOR, 1.80; 95% CI, 1.02-3.17). The risk was lower when more than 5 people outside home were met during semiconfinement, compared with none (aOR, 0.35; 95% CI, 0.16-0.74). Individual risk of household members to be seropositive was lower in large households (22% less per each additional person). During semiconfinement, household members of a COVID-19 case were at very high risk of getting infected, 3 times more than close contacts outside home. This highlights the need to provide clear messages on protective measures applicable at home. For elderly couples, who were especially at risk, providing external support for daily basic activities is essential

AGFORWARD Third Periodic Report: July 2016 to December 2017

Project context The European Union has targets to improve the competitiveness of European agriculture and forestry, whilst improving the environment and the quality of rural life. At the same time there is a need to improve our resilience to climate change and to enhance biodiversity. During the twentieth century, large productivity advances were made by managing agriculture and forestry as separate practices, but often at a high environmental cost. In order to address landscape-scale issues such as biodiversity and water quality, we argue that farmers and society will benefit from considering landuse as a continuum including both agriculture and trees, and that there are significant opportunities for European farmers and society to benefit from a closer integration of trees with agriculture. Agroforestry is the practice of deliberately integrating woody vegetation (trees or shrubs) with crop and/or animal systems to benefit from the resulting ecological and economic interactions.AGFORWARD (Grant Agreement N° 613520) is co-funded by the European Commission, Directorate General for Research & Innovation, within the 7th Framework Programme of RTD. The views and opinions expressed in this report are purely those of the writers and may not in any circumstances be regarded as stating an official position of the European Commissio

An INTEGRAL/IBIS view of Young Galactic SNRs through the 44Ti gamma-ray lines

We present preliminary results of INTEGRAL/IBIS observations on Cas A, Tycho and Vela Junior Supernova remnants in the line emission of 44Ti. This radioactive nucleus is thought to be exclusively produced in supernovae during the first stages of the explosion. It has a lifetime of about 87 y and is then the best indicator of young SNRs, as exemplified by the detection of 44Ti in the youngest known Galactic SNR Cas A with GRO/COMPTEL and latter with BeppoSAX. In this paper, we will focus on this SNR for which we confirm the detection of 44Ti and point out the importance to know the nature of the hard X-ray continuum, the Tycho SNR, for which no indication of 44Ti was ever reported, and Vela Junior, for which the claimed detection of 44Ti with COMPTEL is still controversial. The INTEGRAL/IBIS observations bring new constraints on the nature of these SNRs and on the nucleosynthesis which took place during the explosions.Comment: Accepted for publication in New Astronomy Reviews ("Astronomy with Radioactivites V" conference, Clemson Univ., Sept. 2005). 6 pages, 2 figure