460 research outputs found

    Herschel observations of embedded protostellar clusters in the Rosette molecular cloud

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    The Herschel OB young stellar objects survey (HOBYS) has observed the Rosette molecular cloud, providing an unprecedented view of its star formation activity. These new far-infrared data reveal a population of compact young stellar objects whose physical properties we aim to characterise. We compiled a sample of protostars and their spectral energy distributions that covers the near-infrared to submillimetre wavelength range. These were used to constrain key properties in the protostellar evolution, bolometric luminosity, and envelope mass and to build an evolutionary diagram. Several clusters are distinguished including the cloud centre, the embedded clusters in the vicinity of luminous infrared sources, and the interaction region. The analysed protostellar population in Rosette ranges from 0.1 to about 15 M_☉ with luminosities between 1 and 150 L_☉, which extends the evolutionary diagram from low-mass protostars into the high-mass regime. Some sources lack counterparts at near- to mid-infrared wavelengths, indicating extreme youth. The central cluster and the Phelps & Lada 7 cluster appear less evolved than the remainder of the analysed protostellar population. For the central cluster, we find indications that about 25% of the protostars classified as Class I from near- to mid-infrared data are actually candidate Class 0 objects. As a showcase for protostellar evolution, we analysed four protostars of low- to intermediate-mass in a single dense core, and they represent different evolutionary stages from Class 0 to Class I. Their mid- to far-infrared spectral slopes flatten towards the Class I stage, and the 160 to 70 μm flux ratio is greatest for the presumed Class 0 source. This shows that the Herschel observations characterise the earliest stages of protostellar evolution in detail

    Kinematic structure of massive star-forming regions - I. Accretion along filaments

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    The mid- and far-infrared view on high-mass star formation, in particular with the results from the Herschel space observatory, has shed light on many aspects of massive star formation. However, these continuum studies lack kinematic information. We study the kinematics of the molecular gas in high-mass star-forming regions. We complemented the PACS and SPIRE far-infrared data of 16 high-mass star-forming regions from the Herschel key project EPoS with N2H+ molecular line data from the MOPRA and Nobeyama 45m telescope. Using the full N2H+ hyperfine structure, we produced column density, velocity, and linewidth maps. These were correlated with PACS 70micron images and PACS point sources. In addition, we searched for velocity gradients. For several regions, the data suggest that the linewidth on the scale of clumps is dominated by outflows or unresolved velocity gradients. IRDC18454 and G11.11 show two velocity components along several lines of sight. We find that all regions with a diameter larger than 1pc show either velocity gradients or fragment into independent structures with distinct velocities. The velocity profiles of three regions with a smooth gradient are consistent with gas flows along the filament, suggesting accretion flows onto the densest regions. We show that the kinematics of several regions have a significant and complex velocity structure. For three filaments, we suggest that gas flows toward the more massive clumps are present.Comment: accepted by A&

    Kinematic and Thermal Structure at the onset of high-mass star formation

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    We want to understand the kinematic and thermal properties of young massive gas clumps prior to and at the earliest evolutionary stages of high-mass star formation. Do we find signatures of gravitational collapse? Do we find temperature gradients in the vicinity or absence of infrared emission sources? Do we find coherent velocity structures toward the center of the dense and cold gas clumps? To determine kinematics and gas temperatures, we used ammonia, because it is known to be a good tracer and thermometer of dense gas. We observed the NH3_3(1,1) and (2,2) lines within seven very young high-mass star-forming regions with the VLA and the Effelsberg 100m telescope. This allows us to study velocity structures, linewidths, and gas temperatures at high spatial resolution of 3-5"", corresponding to ∼\sim0.05 pc. We find on average cold gas clumps with temperatures in the range between 10 K and 30 K. The observations do not reveal a clear correlation between infrared emission peaks and ammonia temperature peaks. We report an upper limit for the linewidth of ∼\sim1.3 km s−1^{-1}, at the spectral resolution limit of our VLA observation. This indicates a relatively low level of turbulence on the scale of the observations. Velocity gradients are present in almost all regions with typical velocity differences of 1 to 2 km s−1^{-1} and gradients of 5 to 10 km s−1^{-1} pc−1^{-1}. These velocity gradients are smooth in most cases, but there is one exceptional source (ISOSS23053), for which we find several velocity components with a steep velocity gradient toward the clump centers that is larger than 30 km s−1^{-1} pc−1^{-1}. This steep velocity gradient is consistent with recent models of cloud collapse. Furthermore, we report a spatial correlation of ammonia and cold dust, but we also find decreasing ammonia emission close to infrared emission sources.Comment: 20 pages, 10 figure

    The Spine Of The Swan: A Herschel Study Of The Dr21 Ridge And Filaments In Cygnus X

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    In order to characterise the cloud structures responsible for the formation of high-mass stars, we present Herschel observations of the DR21 environment. Maps of the column density and dust temperature unveil the structure of the DR21 ridge and several connected filaments. The ridge has column densities higher than 1023 cm-2 over a region of 2.3 pc2. It shows substructured column density profiles and branches into two major filaments in the north. The masses in the filaments range between 130 and 1400 M⊙, whereas the mass in the ridge is 15 000 M⊙. The accretion of these filaments onto the DR21 ridge, suggested by a previous molecular line study, could provide a continuous mass inflow to the ridge. In contrast to the striations seen in, e.g., the Taurus region, these filaments are gravitationally unstable and form cores and protostars. These coresformed in the filaments potentially fall into the ridge. Both inflow and collisions of cores could be important to drive the observed high-mass star formation. The evolutionary gradient of star formation running from DR21 in the south to the northern branching is traced by decreasing dust temperature. This evolution and the ridge structure can be explained by two main filamentary components of the ridge that merged first in the south

    Generation of wheat gluten hydrolysates with dipeptidyl peptidase IV (DPP-IV) inhibitory properties

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    peer-reviewedWheat gluten, a Pro-rich dietary protein, was investigated for its potential to produce dipeptidyl peptidase IV (DPP-IV) inhibitory peptides during enzymatic hydrolysis with Debitrase HYW20. Nine gluten hydrolysates (H1–H9) were generated using a 2 factor × 3 level design of experiments (DOE) including the incubation temperature (40, 50 and 60 °C) and the enzyme: substrate ratio (E:S, 0.5, 1.0 and 1.5% (w/w)). Their DPP-IV half maximal inhibitory concentration (IC50) ranged from 0.24 ± 0.02 (H9) to 0.66 ± 0.06 mg mL−1 (H2A and H7) and their degree of hydrolysis (DH) from 31.7 ± 0.9 (H7) to 62.2 ± 3.0% (H6). Gluten and H9, the most potent DPP-IV inhibitory hydrolysate, were subjected to simulated gastrointestinal digestion (SGID), yielding Gluten_CorPP and H9_CorPP, respectively. H9_CorPP had a higher DPP-IV inhibitory potency than Gluten_CorPP (i.e., DPP-IV IC50 values of 0.33 ± 0.03 vs. 1.45 ± 0.26 mg mL−1, respectively). H9 and H9_CorPP both contained relatively potent DPP-IV inhibitory peptides such as Val-Pro-Leu, Trp-Leu and Trp-Pro which were identified by liquid chromatography tandem mass spectrometry (LC-MS/MS). In addition, several sequences possessing features of DPP-IV inhibitory peptides, mostly consisting of a penultimate or C-terminal Pro, were identified within H9. The presence of Pro-containing peptides within H9 may contribute to its stability to digestive enzymes. Gluten hydrolysates may have antidiabetic potential for human

    The Relationship between Dog Ownership, Psychopathological Symptoms and Health-Benefitting Factors in Occupations at Risk for Traumatization

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    Individuals working in high-risk occupations (e.g., emergency staff) are exposed to high levels of occupational stress including traumatic events. Correspondingly, several studies report high rates of mental health problems among these occupations. Pet ownership has been associated with better mental health. However, to date a study on the association between pet ownership and indicators of mental health in these occupations is missing. The present cross-sectional survey (N = 580) investigated pet ownership, attachment to pets, health-benefitting factors (i.e., sense of coherence, trait-resilience, locus of control) and psychopathological symptoms (i.e., general mental health problems, posttraumatic stress, burnout) in medical staff, police officers, and firefighters. Dog owners and non-dog owners showed comparable levels of psychopathological distress and health-benefitting factors. Compared to cat owners, dog owners demonstrated stronger emotional attachment to their pet. Moreover, a stronger attachment was also linked to higher levels of psychopathological symptoms and lower levels of health-benefitting factors. However, the relationship between attachment to pets and health-benefitting factors could be explained by their overlap with psychopathological symptom levels. Overall, our findings are not in line with the notion that pet ownership generally has a health-benefitting effect. Future studies need to investigate circumstances that modulate positive effects of pet ownership

    The relationship between attachment to pets and mental health : the shared link via attachment to humans

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    Background: Several studies have investigated the relationship between emotional attachment to pets and mental health with the majority of studies fnding a negative relationship between emotional attachment to pets and mental health. Interestingly, attachment to pets difers from attachment to humans with studies showing that humans with an insecure attachment style form a particularly strong emotional attachment to their companion animals. Human attachment style is also related to mental health with secure attachment being associated with superior mental health. Building on those fndings, the current study aimed at exploring the role of attachment to humans in the relationship between emotional attachment to pets and mental health. Methods: In this cross-sectional online survey (N=610) we assessed the strength of emotional attachment to pets and attachment to humans. We further collected pet specifc data as well as mental health burden in a sample of German dog owners (Mage=33.12; 92.79% women). We used a mediation model estimating the indirect link between emotional attachment to pets and mental health burden via human attachment and the direct link between emo‑ tional attachment to pets and mental health burden simultaneously. Results: We found that attachment to humans fully mediated the positive association between emotional attach‑ ment to pets and mental health burden. A stronger emotional attachment to one’s dog was associated with lower comfort with depending on or trusting in others, whereby lower comfort with depending on or trusting in others was related to higher mental health burden. Moreover, a stronger attachment to one’s dog was also related to a greater fear of being rejected and unloved (Anxiety), which was, in turn, associated with a higher mental health burden. Conclusion: Our fndings suggest that the positive link between emotional attachment to pets and mental health burden is fully accounted for by its shared variance with insecure attachment to humans in a sample mostly compris‑ ing self-identifed women. Future studies need to examine whether strong emotional bonds with pets may evolve as a compensatory strategy to bufer difcult childhood bonding experiences

    Pre-rehabilitation sense of coherence as a predictor of symptom change after rehabilitation

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    Sense of coherence (SOC) constitutes the key component of salutogenesis theory. It reflects individuals' confidence that their environment is comprehensible and manageable and that their lives are meaningful. Research demonstrates a strong cross-sectional relationship between SOC and mental health. However, little is known about SOC's temporal stability and its potential to predict changes in psychopathological symptom severity in different settings. The goal of the current study was to address this gap. The sample of the two-wave longitudinal study consists of 294 patients receiving inpatient psychotherapeutic (and psychopharmacological) treatment for various psychological disorders at a German psychosomatic rehabilitation clinic. SOC (Antonovsky, Social Science & Medicine, 1993, 36, 725-733) and outcome measures (i.e., general mental health problems, depression and anxiety symptoms) were assessed within two days of arrival and at the end of rehabilitation (week 5/6). SOC was significantly enhanced after treatment whereas psychopathological symptoms were significantly reduced. Regression analyses revealed that pre-treatment SOC was a significant negative predictor of post-treatment symptom severity for all outcome measures even after controlling for pre-treatment symptoms. The current findings provide first evidence that SOC is a significant unique predictor of symptom change. Future studies need to further investigate longitudinal associations between SOC and mental health outcomes in different settings
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