The evolution of HCO+^{+} in molecular clouds using a novel chemical post-processing algorithm

Modeling the internal chemistry of molecular clouds is critical to accurately simulating their evolution. To reduce computational expense, 3D simulations generally restrict their chemical modeling to species with strong heating and cooling effects. We address this by post-processing tracer particles in the SILCC-Zoom molecular cloud simulations. Using a chemical network of 39 species and 299 reactions (including freeze-out of CO and H$_2$O), and a novel iterative algorithm to reconstruct a filled density grid from sparse tracer particle data, we produce time-dependent density distributions for various species. We focus upon the evolution of HCO$^+$, which is a critical formation reactant of CO but is not typically modeled on-the-fly. We analyse the evolution of the tracer particles to assess the regime in which HCO$^+$ production preferentially takes place. We find that the HCO$^+$ content of the cold molecular gas forms in situ around n_\textrm{HCO^+}\simeq10^3-$10^4$ cm$^{-3}$, over a time-scale of approximately 1 Myr, rather than being distributed to this density regime via turbulent mixing from deeper in the cloud. We further show that the dominant HCO$^+$ formation pathway is dependent on the visual extinction, with the reaction H$_3^+$ + CO contributing 90% of the total HCO$^+$ production flux above $A_\textrm{V,3D}=3$. Using our novel grid reconstruction algorithm, we produce the very first maps of the HCO$^+$ column density, $N$(HCO$^+$), and show that it reaches values as high as $10^{15}$ cm$^{-2}$. We find that 50% of the HCO$^+$ mass is located in an $A_\textrm{V}$-range of $\sim$10-30, and in a density range of $10^{3.5}$-$10^{4.5}$ cm$^{-3}$. Finally, we compare our $N$(HCO$^+$) maps to recent observations of W49A and find good agreement.Comment: 23 pages including appendix, 20 figures, submitted to MNRAS, comments are welcom

Demographic, clinical and antibody characteristics of patients with digital ulcers in systemic sclerosis: data from the DUO Registry

OBJECTIVES: The Digital Ulcers Outcome (DUO) Registry was designed to describe the clinical and antibody characteristics, disease course and outcomes of patients with digital ulcers associated with systemic sclerosis (SSc). METHODS: The DUO Registry is a European, prospective, multicentre, observational, registry of SSc patients with ongoing digital ulcer disease, irrespective of treatment regimen. Data collected included demographics, SSc duration, SSc subset, internal organ manifestations, autoantibodies, previous and ongoing interventions and complications related to digital ulcers. RESULTS: Up to 19 November 2010 a total of 2439 patients had enrolled into the registry. Most were classified as either limited cutaneous SSc (lcSSc; 52.2%) or diffuse cutaneous SSc (dcSSc; 36.9%). Digital ulcers developed earlier in patients with dcSSc compared with lcSSc. Almost all patients (95.7%) tested positive for antinuclear antibodies, 45.2% for anti-scleroderma-70 and 43.6% for anticentromere antibodies (ACA). The first digital ulcer in the anti-scleroderma-70-positive patient cohort occurred approximately 5 years earlier than the ACA-positive patient group. CONCLUSIONS: This study provides data from a large cohort of SSc patients with a history of digital ulcers. The early occurrence and high frequency of digital ulcer complications are especially seen in patients with dcSSc and/or anti-scleroderma-70 antibodies

Maladie de Gaucher : analyse finale de l'étude prospective et multicentrique ELIPRO (ELIglustat Patient Reported Outcomes)

L’étude ELIPRO est une étude nationale observationnelle, qui vise à obtenir lespremières données d’utilisation en vie réelle d’éliglustat, traitement oral de premièreintention dans la maladie de Gaucher de type 1 (MG1), avec un focus particuliersur les mesures auto-rapportées par le patient (Patient Reported Outcomes). Nousprésentons ici l’analyse finale de l’étude.International audienc