21 research outputs found

    Near-Infrared Observations of Outflows and YSOs in the Massive Star-Forming Region AFGL 5180

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    Methods: Broad- and narrow-band imaging of AFGL 5180 was made in the NIR with the LBT, in both seeing-limited (\sim0.5\arcsec) and high angular resolution (\sim0.09\arcsec) Adaptive Optics (AO) modes, as well as with HST. Archival ALMA continuum data was also utilized. Results: At least 40 jet knots were identified via NIR emission from H2_2 and [FeII] tracing shocked gas. Bright jet knots outflowing from the central most massive protostar, S4, are detected towards the east of the source and are resolved in fine detail with the AO imaging. Additional knots are distributed throughout the field, likely indicating the presence of multiple driving sources. Sub-millimeter sources detected by ALMA are shown to be grouped in two main complexes, AFGL 5180 M and a small cluster \sim15\arcsec to the south, AFGL 5180 S. From our NIR continuum images we identify YSO candidates down to masses of ∼0.1 M⊙\sim 0.1\:M_\odot. Combined with the sub-mm sources, this yields a surface number density of such YSOs of N∗∼103pc−2N_* \sim 10^3 {\rm pc}^{-2} within a projected radius of about 0.1 pc. Such a value is similar to those predicted by models of both Core Accretion from a turbulent clump environment and Competitive Accretion. The radial profile of N∗N_* is relatively flat on scales out to 0.2~pc, with only modest enhancement around the massive protostar inside 0.05~pc. Conclusions: This study demonstrates the utility of high-resolution NIR imaging, in particular with AO, for detecting outflow activity and YSOs in distant regions. The presented images reveal the complex morphology of outflow-shocked gas within the large-scale bipolar flow of a massive protostar, as well as clear evidence for several other outflow driving sources in the region. Finally, this work presents a novel approach to compare the observed YSO surface number density from our study against different models of massive star formation.Comment: Accepted to Astronomy & Astrophysics (A&A

    Van business case naar value case in de afvalwaterketen : Nieuwe selectiemethode voor toekomstbestendige en duurzame sanitatietechnologieën voor huishoudelijk afvalwater

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    Door het toepassen van systeemdenken en de principes van de circulaire economie is een nieuwe selectiemethode voor toekomstbestendige (duurzame) sanitatietechnologieën voor huishoudelijk afvalwater ontwikkeld. De methode is toepasbaar bij zowel nieuwe projectontwikkeling als bij renovatie van gebouwen en/of riolering en leent zich voor stakeholderparticipatie. Vernieuwend aan deze duurzaamheidscriteria is dat het praktische overwegingen combineert met een duurzaamheidperspectief voor een langere termijn van ten minste 60 jaar. Kwantitatieve en kwalitatieve beoordelingscriteria worden gecombineerd. De resultaten zijn startpunt voor de value case die in aanvulling op een vaak negatieve business case toch tot een positief uitvoeringsbesluit kunnen leiden

    Machian derivation of the Friedmann equation

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    A history of an internet exchange point

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    Treatment of osteochondral defects of the talus in children

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    Osteochondral talar defects are infrequent in children, and little is known about the treatment and clinical outcome of these defects. The purpose of this study was to evaluate the clinical and radiographic outcomes of conservative and primary surgically treated osteochondral talar defects in skeletally immature children. Thirty-six (97%) of 37 eligible patients with a symptomatic primary osteochondral talar defect were evaluated after a median follow-up of 4 years (range 1-12 years). Clinical assessment included the Berndt and Harty outcome question, Ogilvie-Harris score, Visual Analog Scale pain score (at rest, during walking and during running), the American Orthopaedic Foot and Ankle Society (AOFAS) score, and the SF-36. Weight-bearing radiographs were compared with preoperative radiographs with the use of an ankle osteoarthritis classification system. Ninety-two per cent of the initially conservatively treated children [mean age 13 years (SD 2)] were eventually scheduled to undergo surgery. After fixation of the fragment, seven cases (78%) reported a good Berndt and Harty outcome, and two cases (22%) a fair outcome; the median AOFAS score was 95.0 (range 77-100). After debridement and bone marrow stimulation, 13 cases (62%) reported a good Berndt and Harty outcome, three cases (14%) a fair outcome, and five cases (24%) a poor outcome; the median AOFAS score was 95.0 (range 45-100). No signs of degenerative changes were seen in both groups at follow-up. Fixation and debridement and bone marrow stimulation of an osteochondral talar defect are both good surgical options after failed conservative treatment. Retrospective case series, Therapeutic, Level I

    Raptor is critical for increasing the mitochondrial proteome and skeletal muscle force during hypertrophy

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    Loss of skeletal muscle mass and force is of critical importance in numerous pathologies, like age-related sarcopenia or cancer. It has been shown that the Akt-mTORC1 pathway is critical for stimulating adult muscle mass and function, however, it is unknown if mTORC1 is the only mediator downstream of Akt and which intracellular processes are required for functional muscle growth. Here, we show that loss of Raptor reduces muscle hypertrophy after Akt activation and completely prevents increases in muscle force. Interestingly, the residual hypertrophy after Raptor deletion can be completely prevented by administration of the mTORC1 inhibitor rapamycin. Using a quantitative proteomics approach we find that loss of Raptor affects the increases in mitochondrial proteins, while rapamycin mainly affects ribosomal proteins. Taken together, these results suggest that mTORC1 is the key mediator of Akt-dependent muscle growth and its regulation of the mitochondrial proteome is critical for increasing muscle force

    Observations of edge-on protoplanetary disks with ALMA

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    Aims. We aim to study vertical settling and radial drift of dust in protoplanetary disks from a different perspective: an edge-on view. An estimation of the amplitude of settling and drift is highly relevant to understanding planet formation. Methods. We analyze a sample of 12 HST-selected edge-on protoplanetary disks (i.e., seen with high inclinations) for which the vertical extent of the emission layers can be constrained directly. We present ALMA high angular resolution continuum images (~0.1′′) of these disks at two wavelengths, 0.89 and 2.06 mm (respectively ALMA bands 7 and 4), supplemented with archival band 6 data (1.33 mm) where available. Results. Several sources show constant brightness profiles along their major axis with a steep drop at the outer edges. Two disks have central holes with additional compact continuum emission at the location of the central star. For most sources, the millimeter continuum emission is more compact than the scattered light, both in the vertical and radial directions. Six sources are resolved along their minor axis in at least one millimetric band, providing direct information on the vertical distribution of the millimeter grains. For the second largest disk of the sample, Tau 042021, the significant difference in vertical extent between band 7 and band 4 suggests efficient size-selective vertical settling of large grains. Furthermore, the only Class I object in our sample shows evidence of flaring in the millimeter. Along the major axis, all disks are well resolved. Four of them are larger in band 7 than in band 4 in the radial direction, and three have a similar radial extent in all bands. These three disks are also the ones with the sharpest apparent edges (between 80% and 20% of the peak flux, Δr∕r ~ 0.3), and two of them are binaries. For all disks, we also derive the millimeter brightness temperature and spectral index maps. We find that all edge-on disks in our sample are likely optically thick and that the dust emission reveals low brightness temperatures in most cases (brightness temperatures ≤10 K). The integrated spectral indices are similar to those of disks at lower inclination. Conclusions. The comparison of a generic radiative transfer disk model with our data shows that at least three disks are consistent with a small millimeter dust scale height, of a few au (measured at r = 100 au). This is in contrast with the more classical value of hg ~ 10 au derived from scattered light images and from gas line measurements. These results confirm, by direct observations, that large (millimeter) grains are subject to significant vertical settling in protoplanetary disks
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