Context.
The accretion history of protostars remains widely mysterious, even though it represents one of the best ways to understand the protostellar collapse that leads to the formation of stars.
...Aims.
Molecular outflows, which are easier to detect than the direct accretion onto the prostellar embryo, are here used to characterize the protostellar accretion phase in W43-MM1.
Methods.
The W43-MM1 protocluster hosts a sufficient number of protostars to statistically investigate molecular outflows in a single, homogeneous region. We used the CO(2–1) and SiO(5–4) line datacubes, taken as part of an ALMA mosaic with a 2000 AU resolution, to search for protostellar outflows, evaluate the influence that the environment has on these outflows’ characteristics and put constraints on outflow variability in W43-MM1.
Results.
We discovered a rich cluster of 46 outflow lobes, driven by 27 protostars with masses of 1−100
M
⊙
. The complex environment inside which these outflow lobes develop has a definite influence on their length, limiting the validity of using outflows’ dynamical timescale as a proxy of the ejection timescale in clouds with high dynamics and varying conditions. We performed a detailed study of Position–Velocity diagrams of outflows that revealed clear events of episodic ejection. The time variability of W43-MM1 outflows is a general trend and is more generally observed than in nearby, low- to intermediate-mass star-forming regions. The typical timescale found between two ejecta, ~500 yr, is consistent with that found in nearby protostars.
Conclusions.
If ejection episodicity reflects variability in the accretion process, either protostellar accretion is more variable, or episodicity is easier to detect in high-mass star-forming regions than in nearby clouds. The timescale found between accretion events could result from instabilities associated with bursts of inflowing gas arising from the close dynamical environment of high-mass star-forming cores.
The probability distribution function of column density (N-PDF) serves as a powerful tool to characterise the various physical processes that influence the structure of molecular clouds. Studies that ...use extinction maps or H2 column-density maps (N) that are derived from dust show that star-forming clouds can best be characterised by lognormal PDFs for the lower N range and a power-law tail for higher N, which is commonly attributed to turbulence and self-gravity and/or pressure, respectively. The slopes of the power-law tails of the CS, N2H+, and dust PDFs are -1.6, -1.4, and -2.3, respectively, and are thus consistent with free-fall collapse of filaments and clumps. A quasi static configuration of filaments and clumps can also possibly account for the observed N-PDFs, providing they have a sufficiently condensed density structure and external ram pressure by gas accretion is provided. The somehow flatter slopes of N2H+ and CS can reflect an abundance change and/or subthermal excitation at low column densities.
Aims. We report the first detection of the J = 1−0 (102.6 GHz) rotational lines of CF+ (fluoromethylidynium ion) towards CygX-N63, a young and massive protostar of the Cygnus X region. Methods. This ...detection occurred as part of an unbiased spectral survey of this object in the 0.8−3 mm range, performed with the IRAM 30 m telescope. The data were analyzed using a local thermodynamical equilibrium model (LTE model) and a population diagram in order to derive the column density. Results. The line velocity (–4 km s-1) and line width (1.6 km s-1) indicate an origin from the collapsing envelope of the protostar. We obtain a CF+ column density of 4 × 1011 cm-2. The CF+ ion is thought to be a good tracer for C+ and assuming a ratio of 10-6 for CF+/C+, we derive a total number of C+ of 1.2 × 1053 within the beam. There is no evidence of carbon ionization caused by an exterior source of UV photons suggesting that the protostar itself is the source of ionization. Ionization from the protostellar photosphere is not efficient enough. In contrast, X-ray ionization from the accretion shock(s) and UV ionization from outflow shocks could provide a large enough ionizing power to explain our CF+ detection. Conclusions. Surprisingly, CF+ has been detected towards a cold, massive protostar with no sign of an external photon dissociation region (PDR), which means that the only possibility is the existence of a significant inner source of C+. This is an important result that opens interesting perspectives to study the early development of ionized regions and to approach the issue of the evolution of the inner regions of collapsing envelopes of massive protostars. The existence of high energy radiations early in the evolution of massive protostars also has important implications for chemical evolution of dense collapsing gas and could trigger peculiar chemistry and early formation of a hot core.
We report the first detection of the J = 1-0 (102.6 GHz) rotational lines of CFsup + (fluoromethylidynium ion) towards CygX-N63, a young and massive protostar of the Cygnus X region. This detection ...occurred as part of an unbiased spectral survey of this object in the 0.8-3 mm range, performed with the IRAM 30 m telescope. The data were analyzed using a local thermodynamical equilibrium model (LTE model) and a population diagram in order to derive the column density. Surprisingly, CFsup + has been detected towards a cold, massive protostar with no sign of an external photon dissociation region (PDR), which means that the only possibility is the existence of a significant inner source of Csup +. This is an important result that opens interesting perspectives to study the early development of ionized regions and to approach the issue of the evolution of the inner regions of collapsing envelopes of massive protostars.
The accretion history of protostars remains widely mysterious even though it represents one of the best ways to understand the protostellar collapse that leads to the formation of stars. Molecular ...outflows are here used to characterize the protostellar accretion phase in W43-MM1. The W43-MM1 protocluster host a sufficient number of protostars to statistically investigate molecular outflows in a single, homogeneous region. We used the CO(2-1) and SiO(5-4) line datacubes, taken as part of an ALMA mosaic with a 2000 AU resolution, to search for protostellar outflows, evaluate the influence that the environment has on these outflows' characteristics and put constraints on outflow variability in W43-MM1. We discovered a rich cluster of 46 outflow lobes, driven by 27 protostars with masses of 1-100 Msun. The complex environment inside which these outflow lobes develop has a definite influence on their length, limiting the validity of using outflows' dynamical timescales as a proxy of the ejection timescale in clouds with high dynamics and varying conditions. We performed a detailed study of Position-Velocity (PV) diagrams of outflows that revealed clear events of episodic ejection. The time variability of W43-MM1 outflows is a general trend and is more generally observed than in nearby, low- to intermediate-mass star-forming regions. The typical timescale found between two ejecta, about 500 yr, is consistent with that found in nearby protostars. If ejection episodicity reflects variability in the accretion process, either protostellar accretion is more variable or episodicity is easier to detect in high-mass star-forming regions than in nearby clouds. The timescale found between accretion events could be resulting from disk instabilities, associated with bursts of inflowing gas arising from the dynamical environment of high-mass star-forming cores.
We report the first detection of the J = 1 - 0 (102.6 GHz) rotational lines of CF+ (fluoromethylidynium ion) towards CygX-N63, a young and massive protostar of the Cygnus X region. This detection ...occurred as part of an unbiased spectral survey of this object in the 0.8-3 mm range, performed with the IRAM 30m telescope. The data were analyzed using a local thermodynamical equilibrium model (LTE model) and a population diagram in order to derive the column density. The line velocity (-4 km s-1) and line width (1.6 km s-1) indicate an origin from the collapsing envelope of the protostar. We obtain a CF+ column density of 4.10e11 cm-2. The CF+ ion is thought to be a good tracer for C+ and assuming a ratio of 10e-6 for CF+/C+, we derive a total number of C+ of 1.2x10e53 within the beam. There is no evidence of carbon ionization caused by an exterior source of UV photons suggesting that the protostar itself is the source of ionization. Ionization from the protostellar photosphere is not efficient enough. In contrast, X-ray ionization from the accretion shock(s) and UV ionization from outflow shocks could provide a large enough ionizing power to explain our CF+ detection. Surprisingly, CF+ has been detected towards a cold, massive protostar with no sign of an external photon dissociation region (PDR), which means that the only possibility is the existence of a significant inner source of C+. This is an important result that opens interesting perspectives to study the early development of ionized regions and to approach the issue of the evolution of the inner regions of collapsing envelopes of massive protostars. The existence of high energy radiations early in the evolution of massive protostars also has important implications for chemical evolution of dense collapsing gas and could trigger peculiar chemistry and early formation of a hot core.
Column density (N) PDFs serve as a powerful tool to characterize the physical processes that influence the structure of molecular clouds. Star-forming clouds can best be characterized by lognormal ...PDFs for the lower N range and a power-law tail for higher N, commonly attributed to turbulence and self-gravity and/or pressure, respectively. We report here on PDFs obtained from observations of 12CO, 13CO, C18O, CS, and N2H+ in the Cygnus X North region and compare to a PDF derived from dust observations with the Herschel satellite. The PDF of 12CO is lognormal for Av~1-30, but is cut for higher Av due to optical depth effects. The PDFs of C18O and 13CO are mostly lognormal up for Av~1-15, followed by excess up to Av~40. Above that value, all CO PDFs drop, most likely due to depletion. The high density tracers CS and N2H+ exhibit only a power law distribution between Av~15 and 400, respectively. The PDF from dust is lognormal for Av~3-15 and has a power-law tail up to Av~500. Absolute values for the molecular line column densities are, however, rather uncertain due to abundance and excitation temperature variations. Taken the dust PDF face value, we 'calibrate' the molecular line PDF of CS to the one of the dust and determined an abundance CS/H2 of 10^-9. The slopes of the power-law tails of the CS, N2H+, and dust PDFs are consistent with free-fall collapse of filaments and clumps. A quasi static configuration of filaments and clumps can possibly also account for the observed N-PDFs, as long as they have a sufficiently condensed density structure and external ram pressure by gas accretion is provided. The somehow flatter slopes of N2H+ and CS can reflect an abundance change and/or subthermal excitation at low column densities.
De nouvelles manifestations cliniques et radiologiques de la neuromyélite optique ont été découvertes. On parle désormais de spectre de la neuromyélite optique ou NMOSD.
Évaluer l’impact des nouveaux ...critères diagnostiques de NMOSD. Évaluer les indications et la rentabilité des anticorps anti-aquaporine 4 et décrire la population séronégative.
Nous avons réalisé une étude rétrospective monocentrique incluant les patients du centre hospitalier universitaire de Rouen pour qui a été demandée, entre le 17 janvier 2011 et le 20 juin 2014, une recherche d’anticorps anti-aquaporine 4 adressée à Lyon. Le diagnostic final au terme du suivi et le délai pour l’établir, ainsi que les données cliniques, paracliniques, radiologiques ont été relevées.
Au total, 101 patients ont été inclus. Les critères de NMOSD 2014 ont permis de diagnostiquer 8 patients supplémentaires (42 %) dont 4 patients séropositifs avec atteinte monofocale (21 %). Le délai pour poser le diagnostic à partir de la première consultation est significativement plus court avec les critères de 2014 (18,7 mois) qu’avec les critères 2006 (39,3 mois) (p=0,02). Nous n’avons pas trouvé de différence clinique, paraclinique et radiologique significative entre les populations séronégative et séropositive.
Selon les critères 2014, les anticorps anti-AQP4 ont permis d’établir le diagnostic pour 5 patients supplémentaires. Toutes les myélites transverses ne sont pas extensives. En effet, parmi les patients NMOSD, 1 patient a présenté une myélite partielle et 2 une myélite transverse non extensive. Pour les 3 patients NMOSD séronégatifs, l’atteinte clinicoradiologique de la fosse postérieure a permis de poser le diagnostic.
Les nouveaux critères diagnostiques permettent de diagnostiquer plus de patients NMOSD et plus précocement. Les anticorps anti-AQP4 permettent de faire le diagnostic de NMOSD devant des atteintes monofocales.
Summary
This study aims to compare the sagittal global spinal balance of patients consulting for osteoporosis, aged above 50 years with and without osteoporotic vertebral fractures (VFs). Global ...spinal balance is abnormal even in subjects without VFs. VFs and age are determinants of sagittal global balance; however, pelvic parameters play a role in compensatory mechanisms.
Introduction
This study aims to compare the spine curvatures, pelvic parameters, and the sagittal global spinal balance of patients aged above 50 years with and without osteoporotic vertebral fractures.
Methods
Two hundred patients (95 % women) aged 68.3 ± 9.5 years underwent full skeleton radiographs in the standing position, by EOS®, a low dose biplane X-ray imaging system. VFs were evaluated according to Genant’s classification. Spinal (thoracic and lumbar Cobb’s indices, thoracic and lumbar tilts) and pelvic (pelvic tilt, sacral slope, and pelvic incidence) parameters were measured. Sagittal spinal balance was measured using the C7 plumb line and the spinosacral angle (SSA). We compared these parameters in patients with and without vertebral fracture and assessed the determinants of abnormal sagittal spinal balance.
Results
Sixty-nine patients had at least one VF. The sagittal spinal balance was significantly altered in patients with at least one VF, and there was an effect of the number and severity of VFs on parameters. Discriminative value for identification of patients with at least one VF, assessed by Area Under the Curves (AUCs) was 0.652 and 0.706 for C7 plumbline and SSA, respectively. Using multivariate analysis, parameters significantly associated with abnormal spinal balance (SSA) were the presence of at least one VF (OR = 4.96,
P
< 0.0001), age (OR = 1.07,
P
= 0.0006), and high pelvic incidence as a protective factor (OR = 0.93,
P
< 0.0001).
Conclusions
Global spinal balance is abnormal in subjects consulting for osteoporosis, even in subjects without VFs. VFs and age are determinants of abnormal sagittal global balance; however, pelvic parameters play a role in compensatory mechanisms.
Summary
The effect of lumbar osteoarthritis on bone density and trabecular bone score (TBS) was evaluated cross-sectionally and prospectively in postmenopausal women. Lumbar spine osteoarthritis was ...graded according to Kellgren and Lawrence grades. Lumbar osteoarthritis was found to increase lumbar spine bone density, but not TBS.
Introduction
Lumbar osteoarthritis overestimates lumbar bone density (areal bone mineral density (aBMD)). A new texture parameter, the TBS, has been proposed. Calculation of aBMD uses grey level value, while TBS uses grey level variation. Therefore, our hypothesis was that TBS is not influenced by lumbar spine osteoarthritis.
Methods
Menopausal women participating in osteoporosis and ultrasound (OPUS) study were included. They had an aBMD measurement of the spine and hip at baseline and 6-year visit. TBS was calculated on lumbar spine dual-energy X-ray absorptiometry (DXA) scans in an automated manner. The presence of lumbar osteoarthritis was evaluated on baseline radiographs using Kellgren and Lawrence (K&L) classification. Grades range from 0 to 4. In our study, osteoarthritis was defined by at least K&L grade 2.
Results
This study included 1,254 menopausal women (66.7 ± 7.1 years). Among them, 727 attended the 6-year follow-up visit. Patients with lumbar osteoarthritis had an aBMD higher than those without lumbar osteoarthritis at the lumbar spine, but not at the hip. However, the aBMD significantly increased in all sites with the grade of K&L. In contrast, spine TBS was not different between patients with and without lumbar osteoarthritis (
p
= 0.70), and it was not correlated with K&L grade. Spine TBS and aBMD at all sites were negatively correlated with age (
p
< 0.0001). Body mass index was correlated positively with aBMD and negatively with spine TBS (
p
< 0.0001). The 6-year change of aBMD was significant in the hip and nonsignificant in the lumbar spine. That of TBS was significant, with a 3.3 % decrease (
p
< 0.0001), independent of K&L grade (
p
= 0.28).
Conclusion
In postmenopausal women, lumbar osteoarthritis leads to an increase in lumbar spine aBMD. In contrast, spine TBS is not affected by lumbar osteoarthritis.
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