The composition of the protosolar disk and the formation conditions for comets

Conditions in the protosolar nebula have left their mark in the composition of cometary volatiles, thought to be some of the most pristine material in the solar system. Cometary compositions represent the end point of processing that began in the parent molecular cloud core and continued through the collapse of that core to form the protosun and the solar nebula, and finally during the evolution of the solar nebula itself as the cometary bodies were accreting. Disentangling the effects of the various epochs on the final composition of a comet is complicated. But comets are not the only source of information about the solar nebula. Protostellar disks around young stars similar to the protosun provide a way of investigating the evolution of disks similar to the solar nebula while they are in the process of evolving to form their own solar systems. In this way we can learn about the physical and chemical conditions under which comets formed, and about the types of dynamical processing that shaped the solar system we see today. This paper summarizes some recent contributions to our understanding of both cometary volatiles and the composition, structure and evolution of protostellar disks.Comment: To appear in Space Science Reviews. The final publication is available at Springer via http://dx.doi.org/10.1007/s11214-015-0167-

International, Collaborative and Online Education of LIS-students – A Step to the Future?

In this paper, we will analyze and discuss the quality of a project course with an international, collaborative and online format, whose content touches all Swiss information literacy standards. The analysis on a micro-level shall illuminate if the course setup can be declared as a more comprehensive teaching method for LIS students, than the simple teacher- or classroom centered education

Near to Mid-infrared Spectroscopy of (65803) Didymos as Observed by JWST: Characterization Observations Supporting the Double Asteroid Redirection Test

The Didymos binary asteroid was the target of the Double Asteroid Redirection Test (DART) mission, which intentionally impacted Dimorphos, the smaller member of the binary system. We used the Near-Infrared Spectrograph and Mid-Infrared Instrument instruments on JWST to measure the 0.6-5 and 5-20 μm spectra of Didymos approximately two months after the DART impact. These observations confirm that Didymos belongs to the S asteroid class and is most consistent with LL chondrite composition, as was previously determined from its 0.6-2.5 μm reflectance spectrum. Measurements at wavelengths >2.5 μm show Didymos to have thermal properties typical for an S-complex asteroid of its size and to be lacking absorptions deeper than ∼2% due to OH or H2O. Didymos’ mid-infrared emissivity spectrum is within the range of what has been measured on S-complex asteroids observed with the Spitzer Space Telescope and is most consistent with emission from small (<25 μm) surface particles. We conclude that the observed reflectance and physical properties make the Didymos system a good proxy for the type of ordinary chondrite asteroids that cross near-Earth space, and a good representative of likely future impactors. © 2023. The Author(s). Published by the American Astronomical Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Posaconazole treatment of refractory eumycetoma and chromoblastomycosis Tratamento com posaconazol de casos de cromoblastomicose e micetoma maduromicótico resistentes a outros antifúngicos

Eumycetoma and chromoblastomycosis are chronic, disfiguring fungal infections of the subcutaneous tissue that rarely resolve spontaneously. Most patients do not achieve sustained long-term benefits from available treatments; therefore, new therapeutic options are needed. We evaluated the efficacy of posaconazole, a new extended-spectrum triazole antifungal agent, in 12 patients with eumycetoma or chromoblastomycosis refractory to existing antifungal therapies. Posaconazole 800 mg/d was given in divided doses for a maximum of 34 months. Complete or partial clinical response was considered a success; stable disease or failure was considered a nonsuccess. All 12 patients had proven infections refractory to standard therapy. Clinical success was reported for five of six patients with eumycetoma and five of six patients with chromoblastomycosis. Two patients were reported to have stable disease. As part of a treatment-use extension protocol, two patients with eumycetoma who initially had successful outcome were successfully retreated with posaconazole after a treatment hiatus of > 10 months. Posaconazole was well tolerated during long-term administration (up to 1015 d). Posaconazole therapy resulted in successful outcome in most patients with eumycetoma or chromoblastomycosis refractory to standard therapies, suggesting that posaconazole may be an important treatment option for these diseases.<br>Eumicetoma e cromoblastomicose são infecções fúngicas crônicas do tecido subcutâneo que evoluem com aspecto desfigurado, raramente involuindo espontaneamente. A maioria dos pacientes não apresenta melhora sustentada por longo tempo com os tratamentos disponíveis, sendo de grande importância as novas opções terapêuticas. A eficácia do posaconazol, um novo agente antifúngico de amplo espectro do grupo dos triazóis, foi estudada em 12 pacientes com eumicetoma ou cromoblastomicose refratária às terapêuticas antifúngicas disponíveis. Os pacientes receberam por no máximo 34 meses, doses divididas de 800 mg/dia de posaconazol. Resposta clínica parcial ou completa foi considerada como sucesso; doença estável ou falha terapêutica foi considerada como insucesso. Todos os 12 pacientes tinham infecções comprovadas ou prováveis, refratárias à terapêutica padrão preconizada. Sucesso clínico foi registrado em cinco de seis pacientes com eumicetoma e cinco de seis pacientes com cromoblastomicose. Em dois pacientes observou-se doença estável. Como parte do protocolo de extensão do tratamento, dois pacientes com eumicetoma que inicialmente tinham tido sucesso terapêutico e que após um intervalo maior de 10 meses apresentaram recidiva da micose, foram retratados com sucesso com posaconazol. Posaconazol foi bem tolerado durante o longo período de administração (até 1015 dias). A terapêutica com posaconazol foi seguida de sucesso na maioria dos pacientes com eumicetoma ou cromoblastomicose refratária à terapêutica padrão, sugerindo que tal droga possa ser uma importante opção no tratamento de tais doenças

Water Reservoirs in Small Planetary Bodies: Meteorites, Asteroids, and Comets

Asteroids and comets are the remnants of the swarm of planetesimals from which the planets ultimately formed, and they retain records of processes that operated prior to and during planet formation. They are also likely the sources of most of the water and other volatiles accreted by Earth. In this review, we discuss the nature and probable origins of asteroids and comets based on data from remote observations, in situ measurements by spacecraft, and laboratory analyses of meteorites derived from asteroids. The asteroidal parent bodies of meteorites formed ≤4 Ma after Solar System formation while there was still a gas disk present. It seems increasingly likely that the parent bodies of meteorites spectroscopically linked with the E-, S-, M- and V-type asteroids formed sunward of Jupiter's orbit, while those associated with C- and, possibly, D-type asteroids formed further out, beyond Jupiter but probably not beyond Saturn's orbit. Comets formed further from the Sun than any of the meteorite parent bodies, and retain much higher abundances of interstellar material. CI and CM group meteorites are probably related to the most common C-type asteroids, and based on isotopic evidence they, rather than comets, are the most likely sources of the H and N accreted by the terrestrial planets. However, comets may have been major sources of the noble gases accreted by Earth and Venus. Possible constraints that these observations can place on models of giant planet formation and migration are explored