232 research outputs found
ISPY – NaCo imaging survey for planets around young stars : a young companion candidate embedded in the R CrA cloud
Context
Within the NaCo-ISPY exoplanet imaging program, we aim at detecting and characterizing the population of low-mass companions at wide separations (≳10 AU), focusing in particular on young stars either hosting a known protoplanetary disk or a debris disk.
Aims
R CrA is one of the youngest (1-3 Myr) and most promising objects in our sample because of two previous studies that suggested the presence of a close companion. Our aim is to directly image and characterize the companion for the first time.
Methods
We observed R CrA twice with the NaCo instrument at the Very Large Telescope (VLT) in the L' filter with a one year time baseline in between. The high-contrast imaging data were reduced and analyzed and the companion candidate was detected in both datasets. We used artificial negative signals to determine the position and brightness of the companion and the related uncertainties.
Results
The companion is detected at a separation of 196.8 ± 4.5/196.6 ± 5.9 mas (18.7 ± 1.3/18.7 ± 1.4 AU) and position angle of 134.7 ± 0.5 ° /133.7 ± 0.7° in the first/second epoch observation. We measure a contrast of 7.29 ± 0.18/6.70 ± 0.15 mag with respect to the primary. A study of the stellar proper motion rejects the hypothesis that the signal is a background object. The companion candidate orbits in the clockwise direction and, if on a face-on circular orbit, its period is ˜43 - 47 yr. This value disagrees with the estimated orbital motion and therefore a face-on circular orbit may be excluded. Depending on the assumed age, extinction, and brightness of the primary, the stellar companion has a mass between 0.10 ± 0.02 M⊙ and 1.03-0.18+0.20 M⊙ range, if no contribution from circumsecondary material is taken into account.
Conclusions
As already hypothesized by previous studies, we directly detected a low-mass stellar companion orbiting the young Herbig Ae/Be star R CrA. Depending on the age assumptions, the companion is among the youngest forming companions imaged to date, and its presence needs to be taken into account when analyzing the complex circumstellar environment of R CrA
The Impact of EU Norms and Policies on Consumer Protection Enforcement in Serbia
Pursuant to its 2008 Stabilization and Association Agreement governing the process of EU integration, Serbia is obliged to align its consumer protection standards (including those related to enforcement) with those of the EU. This article considers the overall approach to enforcement of consumer law in Serbia, focussing in particular on the extent to which EU enforcement principles have been successfully exported to Serbia and whether the goals of EU consumer policy have been achieved. It argues that the incorporation of EU norms has brought fundamental changes to Serbian enforcement mechanisms at a formal level, such as in relation to mediation processes as well as the introduction of injunctions for the protection of collective consumer interests. In practice, however, the impact of this incorporation is quite limited. A number of factors that restrict the practical effectiveness of the mediation processes and injunctions required by EU law are explored in the article, including weak sanctions, excessive reliance on poorly resourced consumer organizations, absence of a business culture of compliance or a sophisticated and determined consumer protection enforcement culture sufficiently grounded in expertise, as well as an overarching political, legislative, and institutional instability. These factors also undermine the general aim of EU policy to achieve effective consumer protection enforcement in the Serbian context
The transiting multi-planet system HD3167: a 5.7 MEarth Super-Earth and a 8.3 MEarth mini-Neptune
HD3167 is a bright (V=8.9 mag) K0V star observed by the NASA's K2 space
mission during its Campaign 8. It has been recently found to host two small
transiting planets, namely, HD3167b, an ultra short period (0.96 d)
super-Earth, and HD3167c, a mini-Neptune on a relatively long-period orbit
(29.85 d). Here we present an intensive radial velocity follow-up of HD3167
performed with the FIES@NOT, [email protected], and HARPS-N@TNG spectrographs. We
revise the system parameters and determine radii, masses, and densities of the
two transiting planets by combining the K2 photometry with our spectroscopic
data. With a mass of 5.69+/-0.44 MEarth, radius of 1.574+/-0.054 REarth, and
mean density of 8.00(+1.0)(-0.98) g/cm^3, HD3167b joins the small group of
ultra-short period planets known to have a rocky terrestrial composition.
HD3167c has a mass of 8.33 (+1.79)(-1.85) MEarth and a radius of
2.740(+0.106)(-0.100) REarth, yielding a mean density of 2.21(+0.56)(-0.53)
g/cm^3, indicative of a planet with a composition comprising a solid core
surrounded by a thick atmospheric envelope. The rather large pressure scale
height (about 350 km) and the brightness of the host star make HD3167c an ideal
target for atmospheric characterization via transmission spectroscopy across a
broad range of wavelengths. We found evidence of additional signals in the
radial velocity measurements but the currently available data set does not
allow us to draw any firm conclusion on the origin of the observed variation.Comment: 18 pages, 11 figures, 5 table
Glass groups, glass supply and recycling in late Roman Carthage
Carthage played an important role in maritime exchange networks during the Roman and late antique periods. One hundred ten glass fragments dating to the third to sixth centuries CE from a secondary deposit at the Yasmina Necropolis in Carthage have been analysed by electron microprobe analysis (EPMA) to characterise the supply of glass to the city. Detailed bivariate and multivariate data analysis identified different primary glass groups and revealed evidence of extensive recycling. Roman mixed antimony and manganese glasses with MnO contents in excess of 250 ppm were clearly the product of recycling, while iron, potassium and phosphorus oxides were frequent contaminants. Primary glass sources were discriminated using TiO2 as a proxy for heavy minerals (ilmenite/spinel), Al2O3 for feldspar and SiO2 for quartz in the glassmaking sands. It was thus possible to draw conclusions about the chronological and geographical attributions of the primary glass types. Throughout much of the period covered in this study, glassworkers in Carthage utilised glass from both Egyptian and Levantine sources. Based on their geochemical characteristics, we conclude that Roman antimony and Roman manganese glasses originated from Egypt and the Levant, respectively, and were more or less simultaneously worked at Carthage in the fourth century as attested by their mixed recycling (Roman Sb-Mn). In the later fourth and early fifth centuries, glasses from Egypt (HIMT) and the Levant (two Levantine I groups) continued to be imported to Carthage, although the Egyptian HIMT is less well represented at Yasmina than in many other late antique glass assemblages. In contrast, in the later fifth and sixth centuries, glass seems to have been almost exclusively sourced from Egypt in the form of a manganese-decolourised glass originally described and characterised by Foy and colleagues (2003). Hence, the Yasmina assemblage testifies to significant fluctuations in the supply of glass to Carthage that require further attention
Pathogenesis of vestibular schwannoma in ring chromosome 22
<p>Abstract</p> <p>Background</p> <p>Ring chromosome 22 is a rare human constitutional cytogenetic abnormality. Clinical features of neurofibromatosis type 1 and 2 as well as different tumour types have been reported in patients with ring chromosome 22. The pathogenesis of these tumours is not always clear yet.</p> <p>Methods</p> <p>We report on a female patient with a ring chromosome 22 presenting with severe mental retardation, autistic behaviour, café-au-lait macules and facial dysmorphism. Peripheral blood lymphocytes were karyotyped and array CGH was performed on extracted DNA. At the age of 20 years she was diagnosed with a unilateral vestibular schwannoma. Tumour cells were analyzed by karyotyping, array CGH and <it>NF2 </it>mutation analysis.</p> <p>Results</p> <p>Karyotype on peripheral blood lymphocytes revealed a ring chromosome 22 in all analyzed cells. A 1 Mb array CGH experiment on peripheral blood DNA showed a deletion of 5 terminal clones on the long arm of chromosome 22. Genetic analysis of vestibular schwannoma tissue revealed loss of the ring chromosome 22 and a somatic second hit in the <it>NF2 </it>gene on the remaining chromosome 22.</p> <p>Conclusion</p> <p>We conclude that tumours can arise by the combination of loss of the ring chromosome and a pathogenic <it>NF2 </it>mutation on the remaining chromosome 22 in patients with ring chromosome 22. Our findings indicate that patients with a ring 22 should be monitored for NF2-related tumours starting in adolescence.</p
Knowledge about complementary, alternative and integrative medicine (CAM) among registered health care providers in Swedish surgical care: a national survey among university hospitals
<p>Abstract</p> <p>Background</p> <p>Previous studies show an increased interest and usage of complementary and alternative medicine (CAM) in the general population and among health care workers both internationally and nationally. CAM usage is also reported to be common among surgical patients. Earlier international studies have reported that a large amount of surgical patients use it prior to and after surgery. Recent publications indicate a weak knowledge about CAM among health care workers. However the current situation in Sweden is unknown. The aim of this study was therefore to explore perceived knowledge about CAM among registered healthcare professions in surgical departments at Swedish university hospitals.</p> <p>Method</p> <p>A questionnaire was distributed to 1757 registered physicians, nurses and physiotherapists in surgical wards at the seven university hospitals in Sweden from spring 2010 to spring 2011. The questionnaire included classification of 21 therapies into conventional, complementary, alternative and integrative, and whether patients were recommended these therapies. Questions concerning knowledge, research, and patient communication about CAM were also included.</p> <p>Result</p> <p>A total of 737 (42.0%) questionnaires were returned. Therapies classified as complementary; were massage, manual therapies, yoga and acupuncture. Alternative therapies; were herbal medicine, dietary supplements, homeopathy and healing. Classification to integrative therapy was low, and unfamiliar therapies were Bowen therapy, iridology and Rosen method. Therapies recommended by > 40% off the participants were massage and acupuncture. Knowledge and research about CAM was valued as minor or none at all by 95.7% respectively 99.2%. Importance of possessing knowledge about it was valued as important by 80.9%. It was believed by 61.2% that more research funding should be addressed to CAM research, 72.8% were interested in reading CAM-research results, and 27.8% would consider taking part in such research. Half of the participants (55.8%) were positive to learning such therapy. Communication about CAM between patients and the health care professions was found to be rare.</p> <p>Conclusion</p> <p>There is a lack of knowledge about CAM and research about it among registered health care professions in Swedish surgical care. However, in contrast to previous studies the results revealed that the majority perceived it as important to gain knowledge in this field.</p
Mindful Parenting in Mental Health Care
Mindfulness is a form of meditation based on the Buddhist tradition, which has been used over the last two decades to successfully treat a multitude of mental health problems. Bringing mindfulness into parenting (“mindful parenting”) is one of the applications of mindfulness. Mindful parenting interventions are increasingly being used to help prevent and treat mental disorders in children, parenting problems, and prevent intergenerational transmission of mental disorders from parents to children. However, to date, few studies have examined the hypothesized mechanisms of change brought about by mindful parenting. We discuss six possible mechanisms through which mindful parenting may bring about change in parent–child interactions in the context of child and parent mental health problems. These mechanisms are hypothesized to be mediated by the effects of mindfulness on parental attention by: (1) reducing parental stress and resulting parental reactivity; (2) reducing parental preoccupation resulting from parental and/or child psychopathology; (3) improving parental executive functioning in impulsive parents; (4) breaking the cycle of intergenerational transmission of dysfunctional parenting schemas and habits; (5) increasing self-nourishing attention; and (6) improving marital functioning and co-parenting. We review research that has applied mindful parenting in mental health settings, with a focus on evidence for these six mechanisms. Finally, we discuss directions for future research into mindful parenting and the crucial questions that this research should strive to answer
Inhibition of Protein Aggregation: Supramolecular Assemblies of Arginine Hold the Key
BACKGROUND: Aggregation of unfolded proteins occurs mainly through the exposed hydrophobic surfaces. Any mechanism of inhibition of this aggregation should explain the prevention of these hydrophobic interactions. Though arginine is prevalently used as an aggregation suppressor, its mechanism of action is not clearly understood. We propose a mechanism based on the hydrophobic interactions of arginine. METHODOLOGY: We have analyzed arginine solution for its hydrotropic effect by pyrene solubility and the presence of hydrophobic environment by 1-anilino-8-naphthalene sulfonic acid fluorescence. Mass spectroscopic analyses show that arginine forms molecular clusters in the gas phase and the cluster composition is dependent on the solution conditions. Light scattering studies indicate that arginine exists as clusters in solution. In the presence of arginine, the reverse phase chromatographic elution profile of Alzheimer's amyloid beta 1-42 (Abeta(1-42)) peptide is modified. Changes in the hydrodynamic volume of Abeta(1-42) in the presence of arginine measured by size exclusion chromatography show that arginine binds to Abeta(1-42). Arginine increases the solubility of Abeta(1-42) peptide in aqueous medium. It decreases the aggregation of Abeta(1-42) as observed by atomic force microscopy. CONCLUSIONS: Based on our experimental results we propose that molecular clusters of arginine in aqueous solutions display a hydrophobic surface by the alignment of its three methylene groups. The hydrophobic surfaces present on the proteins interact with the hydrophobic surface presented by the arginine clusters. The masking of hydrophobic surface inhibits protein-protein aggregation. This mechanism is also responsible for the hydrotropic effect of arginine on various compounds. It is also explained why other amino acids fail to inhibit the protein aggregation
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