42 research outputs found
Submillimeter Emission from Water in the W3 Region
We have mapped the submillimeter emission from the 1(10)-1(01) transition of
ortho-water in the W3 star-forming region. A 5'x5' map of the W3 IRS4 and W3
IRS5 region reveals strong water lines at half the positions in the map. The
relative strength of the Odin lines compared to previous observations by SWAS
suggests that we are seeing water emission from an extended region. Across much
of the map the lines are double-peaked, with an absorption feature at -39 km/s;
however, some positions in the map show a single strong line at -43 km/s. We
interpret the double-peaked lines as arising from optically thick,
self-absorbed water emission near the W3 IRS5, while the narrower blue-shifted
lines originate in emission near W3 IRS4. In this model, the unusual appearance
of the spectral lines across the map results from a coincidental agreement in
velocity between the emission near W3 IRS4 and the blue peak of the more
complex lines near W3 IRS5. The strength of the water lines near W3 IRS4
suggests we may be seeing water emission enhanced in a photon-dominated region.Comment: Accepted to A&A Letters as part of the special Odin issue; 4 page
Structural Disorder Provides Increased Adaptability for Vesicle Trafficking Pathways
Vesicle trafficking systems play essential roles in the communication between the organelles of eukaryotic cells and also
between cells and their environment. Endocytosis and the late secretory route are mediated by clathrin-coated vesicles,
while the COat Protein I and II (COPI and COPII) routes stand for the bidirectional traffic between the ER and the Golgi
apparatus. Despite similar fundamental organizations, the molecular machinery, functions, and evolutionary characteristics
of the three systems are very different. In this work, we compiled the basic functional protein groups of the three main
routes for human and yeast and analyzed them from the structural disorder perspective. We found similar overall disorder
content in yeast and human proteins, confirming the well-conserved nature of these systems. Most functional groups
contain highly disordered proteins, supporting the general importance of structural disorder in these routes, although some
of them seem to heavily rely on disorder, while others do not. Interestingly, the clathrin system is significantly more
disordered (,23%) than the other two, COPI (,9%) and COPII (,8%). We show that this structural phenomenon enhances
the inherent plasticity and increased evolutionary adaptability of the clathrin system, which distinguishes it from the other
two routes. Since multi-functionality (moonlighting) is indicative of both plasticity and adaptability, we studied its
prevalence in vesicle trafficking proteins and correlated it with structural disorder. Clathrin adaptors have the highest
capability for moonlighting while also comprising the most highly disordered members. The ability to acquire tissue specific
functions was also used to approach adaptability: clathrin route genes have the most tissue specific exons encoding for
protein segments enriched in structural disorder and interaction sites. Overall, our results confirm the general importance of
structural disorder in vesicle trafficking and suggest major roles for this structural property in shaping the differences of
evolutionary adaptability in the three routes
Shortening of clavicle after fracture: Incidence and clinical significance, a 5-year follow-up of 85 patients
We evaluated the incidence and clinical significance of postfracture shortening of the clavicle in 85 patients. There were 71 mid-clavicular fractures and 14 of the lateral end of the clavicle. 46 fractures were primarily undisplaced and 39 displaced. All fractures were nonoperatively treated with sling immobilization. All patients were reexamined 5 years after the fracture. 35 clavicles had healed with at least 5 mm shortening. Clavicles with originally displaced fractures were shorter and radiologically more frequently malunited. Mobility, strength and the functional Constant score were similar in the injured and normal shoulders. Our findings suggest that permanent shortening of the clavicle is common after fracture, but has no clinical significance
Polar vortex evolution during the 2002 Antarctic major warming as observed by the Odin satellite
In September 2002 the Antarctic polar vortex split in two under the influence of a sudden warming. During this event, the Odin satellite was able to measure both ozone (O3) and chlorine monoxide (ClO), a key constituent responsible for the so-called “ozone hole”, together with nitrous oxide (N2O), a dynamical tracer, and nitric acid (HNO3) and nitrogen dioxide (NO2), tracers of denitrification. The submillimeter radiometer (SMR) microwave instrument and the Optical Spectrograph and Infrared Imager System (OSIRIS) UV-visible light spectrometer (VIS) and IR instrument on board Odin have sounded the polar vortex during three different periods: before (19–20 September), during (24–25 September), and after (1–2 and 4–5 October) the vortex split. Odin observations coupled with the Reactive Processes Ruling the Ozone Budget in the Stratosphere (REPROBUS) chemical transport model at and above 500 K isentropic surfaces (heights above 18 km) reveal that on 19–20 September the Antarctic vortex was dynamically stable and chemically nominal: denitrified, with a nearly complete chlorine activation, and a 70% O3 loss at 500 K. On 25–26 September the unusual morphology of the vortex is monitored by the N2O observations. The measured ClO decay is consistent with other observations performed in 2002 and in the past. The vortex split episode is followed by a nearly complete deactivation of the ClO radicals on 1–2 October, leading to the end of the chemical O3 loss, while HNO3 and NO2 fields start increasing. This acceleration of the chlorine deactivation results from the warming of the Antarctic vortex in 2002, putting an early end to the polar stratospheric cloud season. The model simulation suggests that the vortex elongation toward regions of strong solar irradiance also favored the rapid reformation of ClONO2. The observed dynamical and chemical evolution of the 2002 polar vortex is qualitatively well reproduced by REPROBUS. Quantitative differences are mainly attributable to the too weak amounts of HNO3 in the model, which do not produce enough NO2 in presence of sunlight to deactivate chlorine as fast as observed by Odin
Low upper limits on the O 2 abundance from the Odin satellite
For the first time, a search has been conducted in our Galaxy for the 119 GHz transition connecting to the ground state of O 2, using the Odin satellite. Equipped with a sensitive 3 mm receiver (T sys(SSB) = 600 K), Odin has reached unprecedented upper limits on the abundance of O 2, especially in cold dark clouds where the excited state levels involved in the 487 GHz transition are not expected to be significantly populated. Here we report upper limits for a dozen sources. In cold dark clouds we improve upon the published SWAS upper limits by more than an order of magnitude, reaching N(O 2)/N(H 2) ≤ 10 -7 in half of the sources. While standard chemical models are definitively ruled out by these new limits, our results are compatible with several recent studies that derive lower O 2 abundances. Goldsmith et al. (2002) recently reported a SWAS tentative detection of the 487 GHz transition of O 2 in an outflow wing towards ρ Oph A in a combination of 7 beams covering approximately 10′ × 14′. In a brief (1.3 hour integration time) and partial covering of the SWAS region ≈65% if we exclude their central position), we did not detect the corresponding 119 GHz line. Our 3 sigma upper limit on the O 2 column density is 7.3 × 10 15 cm -2. We presently cannot exclude the possibility that the SWAS signal lies mostly outside of the 9′ Odin beam and has escaped our sensitive detector.link_to_subscribed_fulltex
Low upper limits on the O2 abundance from the Odin satellite
NRC publication: Ye