CN rings in full protoplanetary disks around young stars as probes of disk structure

Bright ring-like structure emission of the CN molecule has been observed in protoplanetary disks. We investigate whether such structures are due to the morphology of the disk itself or if they are instead an intrinsic feature of CN emission. With the intention of using CN as a diagnostic, we also address to which physical and chemical parameters CN is most sensitive. A set of disk models were run for different stellar spectra, masses, and physical structures via the 2D thermochemical code DALI. An updated chemical network that accounts for the most relevant CN reactions was adopted. Ring-shaped emission is found to be a common feature of all adopted models; the highest abundance is found in the upper outer regions of the disk, and the column density peaks at 30-100 AU for T Tauri stars with standard accretion rates. Higher mass disks generally show brighter CN. Higher UV fields, such as those appropriate for T Tauri stars with high accretion rates or for Herbig Ae stars or for higher disk flaring, generally result in brighter and larger rings. These trends are due to the main formation paths of CN, which all start with vibrationally excited H2* molecules, that are produced through far ultraviolet (FUV) pumping of H2. The model results compare well with observed disk-integrated CN fluxes and the observed location of the CN ring for the TW Hya disk. CN rings are produced naturally in protoplanetary disks and do not require a specific underlying disk structure such as a dust cavity or gap. The strong link between FUV flux and CN emission can provide critical information regarding the vertical structure of the disk and the distribution of dust grains which affects the UV penetration, and could help to break some degeneracies in the SED fitting. In contrast with C2H or c-C3H2, the CN flux is not very sensitive to carbon and oxygen depletion.Comment: New version of paper, correcting too high H2 excitation rates and consequently too high CN column densities. Qualitative conclusions of the paper remain unchanged. Quantitatively, the CN column densities are an order of magnitude lower whereas fluxes decrease by a factor of 3-4. Rings are larger by up to a factor of 2. 13 pages, 19 figures, accepted for publication in A&

The Presence of Coups d\u27État within Revolutions: Effects on Population Health

The present study is a comparative approach to revolutions and their effect on population health during the post-conflict period. Specifically, it attempts to determine whether revolutions that are accompanied by a coup d\u27état have a significant negative impact on post-revolution population health. Degree of revolutionary violence, governmental structures, and pre-revolution health systems is of particular interest as relevant variables. The study focuses on the Latin American countries of Nicaragua and Chile due to their similar region and timeframe. The revolutions and accompanying coup d\u27état in both of these countries do not demonstrate different patterns on public health in the post-conflict period; rather, governmental structure and regime type were found to be more influential on a nation s post-revolution health status than the occurrence of a coup d\u27état. It has also been found that the implementation of effective programs, community participation, and population expectation are the primary factors that influence post-revolution health status

Planet formation in the PDS 70 system: Constraining the atmospheric chemistry of PDS 70b and c

Understanding the chemical link between protoplanetary disks and planetary atmospheres is complicated by the fact that the popular targets in the study of disks and planets are widely separated both in space and time. The 5 Myr PDS 70 systems offers a unique opportunity to directly compare the chemistry of a giant planet's atmosphere to the chemistry of its natal disk. To that end, we derive our current best physical and chemical model for the PDS 70 disk through forward modelling of the $^{12}$CO, C$^{18}$O, and C$_2$H emission radial profiles with the thermochemical code DALI and find a volatile C/O ratio above unity in the outer disk. Using what we know of the PDS 70 disk today, we analytically estimate the properties of the disk as it was 4 Myr in the past when we assume that the giant planets started their formation, and compute a chemical model of the disk at that time. We compute the formation of PDS 70b and PDS 70c using the standard core accretion paradigm and account for the accretion of volatile and refractory sources of carbon and oxygen to estimate the resulting atmospheric carbon-to-oxygen number ratio (C/O) for these planets. Our inferred C/O ratio of the gas in the PDS 70 disk indicates that it is marginally carbon rich relative to the stellar C/O = 0.44 which we derive from an empirical relation between stellar metallicity and C/O. Under the assumption that the disk has been carbon rich for most of its lifetime, we find that the planets acquire a super-stellar C/O in their atmospheres. If the carbon-rich disk is a relatively recent phenomenon (i.e. developed after the formation of the planets at $\sim 1$ Myr) then the planets should have close to the stellar C/O in their atmospheres. This work lays the groundwork to better understand the disk in the PDS 70 system as well as the planet formation scenario that produce its planets.Comment: 18 pages, 14 figures, 5 tables, accepted for publication in A&

Characterizing rings in terms of the extent of injectivity and projectivity of their modules

Given a ring R, we define its right i-profile (resp. right p-profile) to be the collection of injectivity domains (resp. projectivity domains) of its right R-modules. We study the lattice theoretic properties of these profiles and consider ways in which properties of the profiles may determine the structure of rings and viceversa. We show that the i-profile is isomorphic to an interval of the lattice of linear filters of right ideals of R, and is therefore modular and coatomic. In particular, we give a practical characterization of the i-profile of a right artinian ring. We show through an example that the p-profile is not necessarily a set, and also characterize the right p-profile of a right perfect ring. The study of rings in terms of their (i- or p-)profile was inspired by the study of rings with no (i- or p-) middle class, initiated in recent papers by Er, L\'opez-Permouth and S\"okmez, and by Holston, L\'opez-Permouth and Orhan-Ertas. In this paper, we obtain further results about these rings and we also use our results to provide a characterization of a special class of QF-rings in which the injectivity and projectivity domains of any module coincide.Comment: 19 pages, examples and propositions added. Title change

Functional group analysis by H NMR/chemical derivatization for the characterization of organic aerosol from the SMOCC field campaign

Water soluble organic compounds (WSOC) in aerosol samples collected in the Amazon Basin in a period encompassing the middle/late dry season and the beginning of the wet season, were investigated by H NMR spectroscopy. HiVol filter samples (PM2.5 and PM>2.5) and size-segregated samples from multistage impactor were subjected to H NMR characterization. The H NMR methodology, recently developed for the analysis of organic aerosol samples, has been improved by exploiting chemical methylation of carboxylic groups with diazomethane, which allows the direct determination of the carboxylic acid content of WSOC. The content of carboxylic carbons for the different periods and sizes ranged from 12% to 20% of total measured carbon depending on the season and aerosol size, with higher contents for the fine particles in the transition and wet periods with respect to the dry period. A comprehensive picture is presented of WSOC functional groups in aerosol samples representative of the biomass burning period, as well as of transition and semi-clean atmospheric conditions. A difference in composition between fine (PM2.5) and coarse (PM>2.5) size fractions emerged from the NMR data, the former showing higher alkylic content, the latter being largely dominated by R-O-H (or R-O-R') functional groups. Very small particles (<0.14 &mu;m), however, present higher alkyl-chain content and less oxygenated carbons than larger fine particles (0.42&ndash;1.2 &mu;m). More limited variations were found between the average compositions in the different periods of the campaign

Human adipose stromal cells (ASC) for the regeneration of injured cartilage display genetic stability after in vitro culture expansion

Mesenchymal stromal cells are emerging as an extremely promising therapeutic agent for tissue regeneration due to their multi-potency, immune-modulation and secretome activities, but safety remains one of the main concerns, particularly when in vitro manipulation, such as cell expansion, is performed before clinical application. Indeed, it is well documented that in vitro expansion reduces replicative potential and some multi-potency and promotes cell senescence. Furthermore, during in vitro aging there is a decrease in DNA synthesis and repair efficiency thus leading to DNA damage accumulation and possibly inducing genomic instability. The European Research Project ADIPOA aims at validating an innovative cell-based therapy where autologous adipose stromal cells (ASCs) are injected in the diseased articulation to activate regeneration of the cartilage. The primary objective of this paper was to assess the safety of cultured ASCs. The maintenance of genetic integrity was evaluated during in vitro culture by karyotype and microsatellite instability analysis. In addition, RT-PCR array-based evaluation of the expression of genes related to DNA damage signaling pathways was performed. Finally, the senescence and replicative potential of cultured cells was evaluated by telomere length and telomerase activity assessment, whereas anchorage-independent clone development was tested in vitro by soft agar growth. We found that cultured ASCs do not show genetic alterations and replicative senescence during the period of observation, nor anchorage-independent growth, supporting an argument for the safety of ASCs for clinical use

Detailed neutronic study of the power evolution for the European Sodium Fast Reactor during a positive insertion of reactivity

Abstract The new reactor concepts proposed in the Generation IV International Forum require the development and validation of new components and new materials. Inside the Collaborative Project on the European Sodium Fast Reactor, several accidental scenario have been studied. Nevertheless, none of them coped with mechanical safety assessment of the fuel cladding under accidental conditions. Among the accidental conditions considered, there is the unprotected transient of overpower (UTOP), due to the insertion, at the end of the first fuel cycle, of a positive reactivity into the reactor core as a consequence of the unexpected runaway of one control rod. The goal of the study was the search for a detailed distribution of the fission power, in the radial and axial directions, within the power peaked fuel pin under the above accidental conditions. Results show that after the control rod ejection an increase from 658 W/cm 3 to 894 W/cm 3 , i.e. of some 36%, is expected for the power peaked fuel pin. This information will represent the base to investigate, in a future work, the fuel cladding safety margin