Mid-Infrared interferometry of dust around massive evolved stars

We report long-baseline interferometric measurements of circumstellar dust around massive evolved stars with the MIDI instrument on the Very Large Telescope Interferometer and provide spectrally dispersed visibilities in the 8-13 micron wavelength band. We also present diffraction-limited observations at 10.7 micron on the Keck Telescope with baselines up to 8.7 m which explore larger scale structure. We have resolved the dust shells around the late type WC stars WR 106 and WR 95, and the enigmatic NaSt1 (formerly WR 122), suspected to have recently evolved from a Luminous Blue Variable (LBV) stage. For AG Car, the protoypical LBV in our sample, we marginally resolve structure close to the star, distinct from the well-studied detached nebula. The dust shells around the two WC stars show fairly constant size in the 8-13 micron MIDI band, with gaussian half-widths of ~ 25 to 40 mas. The compact dust we detect around NaSt1 and AG Car favors recent or ongoing dust formation. Using the measured visibilities, we build spherically symmetric radiative transfer models of the WC dust shells which enable detailed comparison with existing SED-based models. Our results indicate that the inner radii of the shells are within a few tens of AU from the stars. In addition, our models favor grain size distributions with large (~ 1 micron) dust grains. This proximity of the inner dust to the hot central star emphasizes the difficulty faced by current theories in forming dust in the hostile environment around WR stars. Although we detect no direct evidence for binarity for these objects, dust production in a colliding-wind interface in a binary system is a feasible mechanism in WR systems under these conditions.Comment: 21 pages, 4 tables, 13 figures. Accepted for publication in the Astrophysical Journa

Mother's and children's ADHD genetic risk, household chaos and children's ADHD symptoms:A gene–environment correlation study

BACKGROUND: Chaotic home environments may contribute to children's attention‐deficit hyperactivity disorder (ADHD) symptoms. However, ADHD genetic risk may also influence household chaos. This study investigated whether children in chaotic households had more ADHD symptoms, if mothers and children with higher ADHD genetic risk lived in more chaotic households, and the joint association of genetic risk and household chaos on the longitudinal course of ADHD symptoms across childhood. METHODS: Participants were mothers and children from the Environmental Risk (E‐Risk) Longitudinal Twin Study, a UK population‐representative birth cohort of 2,232 twins. Children's ADHD symptoms were assessed at ages 5, 7, 10 and 12 years. Household chaos was rated by research workers at ages 7, 10 and 12, and by mother's and twin's self‐report at age 12. Genome‐wide ADHD polygenic risk scores (PRS) were calculated for mothers (n = 880) and twins (n = 1,999); of these, n = 871 mothers and n = 1,925 children had information on children's ADHD and household chaos. RESULTS: Children in more chaotic households had higher ADHD symptoms. Mothers and children with higher ADHD PRS lived in more chaotic households. Children's ADHD PRS was associated with household chaos over and above mother's PRS, suggesting evocative gene–environment correlation. Children in more chaotic households had higher baseline ADHD symptoms and a slower rate of decline in symptoms. However, sensitivity analyses estimated that gene–environment correlation accounted for a large proportion of the association of household chaos on ADHD symptoms. CONCLUSIONS: Children's ADHD genetic risk was independently associated with higher levels of household chaos, emphasising the active role of children in shaping their home environment. Our findings suggest that household chaos partly reflects children's genetic risk for ADHD, calling into question whether household chaos directly influences children's core ADHD symptoms. Our findings highlight the importance of considering parent and child genetic risk in relation to apparent environmental exposures

Association Between Metabolic Syndrome and Periodontal Disease Measures in Postmenopausal Women: The Buffalo OsteoPerio Study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141377/1/jper1489.pd

Nov sistem za identifikaciju čestica u području 3 − 8 GeV/c

A threshold imaging Cherenkov (TIC) detector, in conjunction with a tracking device, has been developed to allow pion/kaon, proton identification in the 3–8 GeV/c range of momenta. The most important feature of the system is that it allows spatial identification of the photons of particles above the Cherenkov threshold and their correlation to a particular track. The TIC detector uses a MWPC detector with TMAE for photon conversion into electrons. The first results obtained in ultrarelativistic lead–lead collisions at the CERN SPS accelerator are presented. In a recent development use of a solid CsI cathode instead of TMAE has been successfully tested in proton–lead collisions at the CERN SPS.Razvijen je pozicioni detektor fotona Cerenkovljeva zračenja iznad praga emisije (TIC), koji omogućuje (u sklopu sistema za mjerenje tragova čestica) razlikovanje piona od kaona i protona u području između praga emisije za pione i za kaone t.j između 3 i 8 GeV/c. Najbitnija odlika sistema jest mogućnost dvodimenzijske lokalizacije emitiranih fotona i njihovo jednoznačno pridruživanje određenom tragu čestice koji je odreden drugim detektorima. Detektor TIC primjenjuje višezičane proporcionalne komore s TMAE dodanom brojačkom plinu za konverziju fotona u elektrone. Prikazuju se prvi rezultati dobiveni u ultrarelativističkim sudarima iona olova s metom olova u SPS akceleratoru u CERNu. Nedavno je upotreba čvrstih fotokatoda umjesto TMAE bila uspješno iskušana procesima sudara protona s olovom u SPS akceleratoru

Nov sistem za identifikaciju čestica u području 3 − 8 GeV/c

A threshold imaging Cherenkov (TIC) detector, in conjunction with a tracking device, has been developed to allow pion/kaon, proton identification in the 3–8 GeV/c range of momenta. The most important feature of the system is that it allows spatial identification of the photons of particles above the Cherenkov threshold and their correlation to a particular track. The TIC detector uses a MWPC detector with TMAE for photon conversion into electrons. The first results obtained in ultrarelativistic lead–lead collisions at the CERN SPS accelerator are presented. In a recent development use of a solid CsI cathode instead of TMAE has been successfully tested in proton–lead collisions at the CERN SPS.Razvijen je pozicioni detektor fotona Cerenkovljeva zračenja iznad praga emisije (TIC), koji omogućuje (u sklopu sistema za mjerenje tragova čestica) razlikovanje piona od kaona i protona u području između praga emisije za pione i za kaone t.j između 3 i 8 GeV/c. Najbitnija odlika sistema jest mogućnost dvodimenzijske lokalizacije emitiranih fotona i njihovo jednoznačno pridruživanje određenom tragu čestice koji je odreden drugim detektorima. Detektor TIC primjenjuje višezičane proporcionalne komore s TMAE dodanom brojačkom plinu za konverziju fotona u elektrone. Prikazuju se prvi rezultati dobiveni u ultrarelativističkim sudarima iona olova s metom olova u SPS akceleratoru u CERNu. Nedavno je upotreba čvrstih fotokatoda umjesto TMAE bila uspješno iskušana procesima sudara protona s olovom u SPS akceleratoru