Climate and atmospheric models of rocky planets: habitability and observational properties

The quest for atmospheric spectral signatures that may witness biological activity in exoplanets is focused on rocky planets. The best targets for future, challenging spectroscopic observations will be selected among potentially habitable planets. Surface habitability can be quantified and explored with climate and atmospheric models according to temperature-based criteria. The conceptual, modellistic, technological and interpretative complexity of the problem requires to develop flexible climate and atmospheric models suited for a comprehensive exploration of observationally unconstrained parameters, and to simulate and interpret definitely non-terrestrial conditions. We present a summary and preliminary results on the work we are performing on multi-parametric explorations of the habitability and observational properties of rocky planets.Comment: to appear on MemSAIt, vol 94. Proceedings of the Hack100 Conference: Past, Present and Future of Astrophysical Spectroscopy, 6-10 June 2022, Trieste, Ital

On the similarity of dust flows in the inner coma of comets

The atmosphere of a comet is formed by the sublimation, due to solar illumination, of its volatile component and the dust particles ejected from its nucleus and entrained by the gas flow. Contemporary dusty-gas coma models take into account numerous physical processes occurring in the coma and a complex geometry of the nucleus. For the description of the dusty-gas flow in the coma, such models introduce a large number of governing parameters characterizing physical properties and processes. The relative role of these processes is not easy to ascribe therefore a relevant inter-comparison of model results becomes difficult. The present work introduces a set of universal, dimensionless parameters, which characterize the dust motion in the inner cometary coma. This approach allows one to: (i) reduce the number of parameters for analysis; (ii) reveal dust flows similarities; (iii) rescale the available numerical solutions. The present work demonstrates application of this approach to a realistic coma model. Description of dust motion with dimensionless parameters allows us to make a parametric study for a broad range of conditions and to find simple analytic approximations (via a polynomial function) of the numerical results suitable for rough estimations of dust density in the coma

A semi-classical over-barrier model for charge exchange between highly charged ions and one-optical electron atoms

Absolute total cross sections for electron capture between slow, highly charged ions and alkali targets have been recently measured. It is found that these cross sections follow a scaling law with the projectile charge which is different from the one previously proposed basing on a classical over-barrier model (OBM) and verified using rare gases and molecules as targets. In this paper we develop a "semi-classical" (i.e. including some quantal features) OBM attempting to recover experimental results. The method is then applied to ion-hydrogen collisions and compared with the result of a sophisticated quantum-mechanical calculation. In the former case the accordance is very good, while in the latter one no so satisfactory results are found. A qualitative explanation for the discrepancies is attempted.Comment: RevTeX, uses epsf; 6 pages text + 3 EPS figures Journal of Physics B (scehduled March 2000). This revision corrects fig.

The dust-to-ices ratio in comets and Kuiper belt objects

Comet 67P/Churyumov-Gerasimenko (67P hereinafter) is characterized by a dust transfer from the southern hemi-nucleus to the night-side northern dust deposits, which constrains the dust-to-ices mass ratio inside the nucleus to values a factor of 2 larger than that provided by the lost mass of gas and non-volatiles. This applies to all comets because the gas density in all night comae cannot prevent the dust fallback. Taking into account Grain Impact Analyser and Dust Accumulator (GIADA) data collected during the entire Rosetta mission, we update the average dust bulk density to ρD=785 +520/−115 $\rho {}{}_{\rm D} = 785_{-115}^{+520}$ kg m$^-3$ that, coupled to the 67P nucleus bulk density, confirms an average dust-to-ices mass ratio δ = 7.5 inside 67P. The improved dust densities are consistent with a mixture of (20 ± 8) per cent of ices, (4 ± 1) per cent of Fe sulphides, (22 ± 2) per cent of silicates and (54 ± 5) per cent of hydrocarbons, on average volume abundances. These values correspond to solar chemical abundances, as suggested by the elemental C/Fe ratio observed in 67P. The ice content in 67P matches that inferred in Kuiper belt objects, (20 ± 12) per cent on average volume abundance and suggests a water content in all trans-Neptunian objects lower than in CI chondrites. The 67P icy pebbles and the dust collected by GIADA have a microporosity of (49 ± 5) and (59 ± 8) per cent, respectively

Immunoblastic morphology as a possible prognostic indicator for the outcome of the patients with diffuse large B cell lymphoma in era of the rituximab based treatment: single centre experience

Recently the results from one large prospective study indicated that immunoblastic morphology and not immunohistohemical features predict the outcome of the Diffuse large B lymphoma (DLBL). In order to investigate the prediction value of the immunoblastic morphology (IB) as a possible prognostic indicator for the outcome of our DLBL patient treated with the Rituximab (R)-CHOP regimen we conducted a retrospective study. Our study enrolled 192 DLBL patients diagnosed and treated at the University Clinic of Hematology in the period between February 2002 and December 2007. They were all treated with R-CHOP regimen and the median follow-up of the patient was 36 months. We analyzed the biopsy samples immunohistochemically for markers of germinal center (BCL6), post-germinal center (MUM1) and apoptosis (BCL2).The patients were categorized as DLBL(132; 68.7%), IB(60; 31.2). The median overall survival time (OS) were 59.3 months in DLBL group and 42.2 months in IB group, and time to treatment (TT) were 56.8 and 30.6 months respectively for the IB group. The DLBL and IB groups were comparable regarding the age, gender distributions and all others already established prognostic parameters as performance status, advanced IPI, albumin level except for the low IPI 0-2 which was statistically associated with the DLBL group (p=.024). Our results did not show any statistical survival advantage and better outcome for the patient classified as DLBL when treated with R-CHOP and indicate that immunohistohemical markers do not really reflect the molecular diversity of the tumor.  Our work shows that IB morphology is a major risk factor in DLBL patients treated with R-CHOP. Therefore this morphology appears to capture some adverse molecular events that a currently hard to detect with routine diagnostic procedures.

Multiple sulfatase deficiency with neonatal manifestation.

Multiple Sulfatase Deficiency (MSD; OMIM 272200) is a rare autosomal recessive inborn error of metabolism caused by mutations in the sulfatase modifying factor 1 gene, encoding the formylglycine-generating enzyme (FGE), and resulting in tissue accumulation of sulfatides, sulphated glycosaminoglycans, sphingolipids and steroid sulfates. Less than 50 cases have been published so far. We report a new case of MSD presenting in the newborn period with hypotonia, apnoea, cyanosis and rolling eyes, hepato-splenomegaly and deafness. This patient was compound heterozygous for two so far undescribed SUMF1 mutations (c.191C > A; p.S64X and c.818A > G; p.D273G)

GIADA performance during Rosetta mission scientific operations at comet 67P

The Grain Impact Analyser and Dust Accumulator (GIADA) instrument onboard Rosetta studied the dust environment of comet 67P/Churyumov–Gerasimenko from 3.7 au inbound, through perihelion, to 3.8 au outbound, measuring the dust flow and the dynamic properties of individual particles. GIADA is composed of three subsystems: 1) Grain Detection System (GDS); 2) Impact Sensor (IS); and 3) Micro-Balances System (MBS). Monitoring the subsystems’ performance during operations is an important element for the correct calibration of scientific measurements. In this paper, we analyse the GIADA inflight calibration data obtained by internal calibration devices for the three subsystems during the period from 1 August 2014 to 31 October 2015. The calibration data testify a nominal behaviour of the instrument during these fifteen months of mission; the only exception is a minor loss of sensitivity for one of the two GDS receivers, attributed to dust contamination

Severe peripheral joint laxity is a distinctive clinical feature of spondylodysplastic-ehlers-danlos syndrome (Eds)-b4galt7 and spondylodysplastic-eds-b3galt6

Variations in genes encoding for the enzymes responsible for synthesizing the linker region of proteoglycans may result in recessive conditions known as “linkeropathies”. The two phenotypes related to mutations in genes B4GALT7 and B3GALT6 (encoding for galactosyltransferase I and II respectively) are similar, characterized by short stature, hypotonia, joint hypermobility, skeletal features and a suggestive face with prominent forehead, thin soft tissue and prominent eyes. The most outstanding feature of these disorders is the combination of severe connective tissue involvement, often manifesting in newborns and infants, and skeletal dysplasia that becomes apparent during childhood. Here, we intend to more accurately define some of the clinical features of B4GALT7 and B3GALT6-related conditions and underline the extreme hypermobility of distal joints and the soft, doughy skin on the hands and feet as features that may be useful as the first clues for a correct diagnosis

Determining the dust environment of an unknown comet for a spacecraft flyby: The case of ESA’s Comet Interceptor mission

Context. An assessment of the dust environment of a comet is needed for data analysis and planning spacecraft missions, such as ESA’s Comet Interceptor (CI) mission. The distinctive feature of CI is that the target object will be defined shortly before (or even after) launch; as a result, the properties of the nucleus and dust environment are poorly constrained, and therefore make the assessment of the dust environment challenging. Aims. The main goal of the work is to provide realistic estimations of a dust environment based on very general parameters of possible target objects. Methods. Contemporary numerical models of a dusty-gas coma were used to obtain spatial distribution of dust for a given set of parameters. By varying parameters within a range of possible values, we obtained an ensemble of possible dust distributions. Then, this ensemble was statistically evaluated in order to define the most probable cases and hence reduce the dispersion. This ensemble can not only be used to estimate the likely dust abundance along a flyby trajectory of a spacecraft, for example, but also to quantify the associated uncertainty. Results. We present a methodology of the dust environment assessment for the case when the target comet is not known beforehand (or when its parameters are known with large uncertainty). We provide an assessment of dust environment for the CI mission. We find that the lack of knowledge of any particular comet results in very large uncertainties (~3 orders of magnitude) for the dust densities within the coma. The most sensitive parameters affecting the dust densities are the dust size distribution, the dust production rate, and coma brightness, often quantified by Afρ. Further, the conversion of a coma’s brightness (Afρ) to a dust production rate is poorly constrained. The dust production rate can only be estimated down to an uncertainty of ~0.5 orders of magnitude if the dust size distribution is known in addition to the Afρ. Conclusions. To accurately predict the dust environment of a poorly known comet, a statistical approach needs to be taken to properly reflect the uncertainties. This can be done by calculating an ensemble of comae covering all possible combinations within parameter space as shown in this work