Context. The Odin satellite is now into its sixteenth year of operation, much surpassing its design life of two years. One of the sources which Odin has observed in great detail is the Sgr A complex in the centre of the Milky Way. Aims. To study the presence of NH3 in the Galactic centre and spiral arms. Methods. Recently, Odin has made complementary observations of the 572 GHz NH3 line towards the SgrA + 50 km s(-1) cloud and circumnuclear disk (CND). Results. Significant NH3 emission has been observed in both the + 50 km s(-1) cloud and the CND. Clear NH3 absorption has also been detected in many of the spiral arm features along the line of sight from the Sun to the core of our Galaxy. Conclusions. The very large velocity width (80 km s 1) of the NH3 emission associated with the shock region in the southwestern part of the CND may suggest a formation / desorption scenario similar to that of gas-phase H2O in shocks / outflows.

We report observations of the reactive molecular ions OH, H2O, and H3O towards Orion KL with Herschel/HIFI. All three N = 1−0 finestructure transitions of OH at 909, 971, and 1033 GHz and both fine-structure components of the doublet ortho-H2O 111−000 transition at 1115 and 1139 GHz were detected; an upper limit was obtained for H3O. OH and H2O are observed purely in absorption, showing a narrow component at the source velocity of 9 km s−1, and a broad blueshifted absorption similar to that reported recently for HF and para-H 2 O, and attributed to the low velocity outflow of Orion KL. We estimate column densities of OH and H2O for the 9 km s−1 component of 9±3×1012 cm−2 and 7±2×1012 cm−2, and those in the outflow of 1.9±0.7×1013 cm−2 and 1.0±0.3×1013 cm−2. Upper limits of 2.4×1012 cm−2 and 8.7×1012 cm−2 were derived for the column densities of ortho and para-H3O from transitions near 985 and 1657 GHz. The column densities of the three ions are up to an order of magnitude lower than those obtained from recent observations of W31C and W49N. The comparatively low column densities may be explained by a higher gas density despite the assumption of a very high ionization rate.

We present an analysis for point sources of a systematic imaging of the Ophiuchi molecular cloud with the mid-infrared camera ISOCAM at 6.7 m and 14.3 m. This two-wavelength mid-IR survey is invaluable to recognize most of the young stars with IR excesses embedded in the cloud, and therefore provides a more complete census of the young stars in Oph. Most of these ISOCAM-selected sources are also near-IR sources, it is then possible to estimate with a good accuracy their stellar luminosities and to build a new luminosity function of the Oph embedded cluster. The modeling of this luminosity function using time-dependent mass-luminosity relationships from recent PMS tracks shows that the mass function in Oph sharply attens at a characteristic mass. It is possible to t the observed luminosity function with a mass function which attens at 0.5 M like the IMF favorised by Kroupa et al. (1993), only if the Oph embedded cluster is younger than 0.5 Myr. If the cluster is older (more around 1.0 Myr) the t is good with a sharp attening at M ? 1:0 M which is the value favorised by Scalo (1998) for instance. ISO is an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA.

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.

We have developed a Simulator for virtual phacoemulsification Surgery. In the Current study, the performance of one experienced cataract Surgeon was compared to the performance of four Subjects naive to cataract Surgery. They all operated on the same virtual patient and a number of different response variables were measured. It was found that the experienced Subject performed better than the naive Subjects on almost all response variables. This indicates that the simulator developed by LIS is authentic for phaco emulsification Surgery. The lack of negative effects in case of complications during virtual phacoemulsification Surgery makes the phaco simulator that we developed a very attractive tool for learning phacoemulsification surgery.

s of recently accepted papers Two-dimensional Distributions and Column Densities of Gaseous Molecules in Protoplanetary Disks II.—Deuterated Species and UV Shielding by Ambient Clouds Y. Aikawa and E. Herbst 1 Department of Earth and Planetary Sciences, Faculty of Science, Kobe University, Kobe 657-8501, Japan 2 Departments of Physics and Astronomy, The Ohio State University, Columbus, OH 43210, USA E-mail contact: aikawa@jet.planet.sci.kobe-u.ac.jp We have investigated the two-dimensional (R,Z) distribution of deuterated molecular species in circumstellar disks around young stellar objects. The abundance ratios between singly deuterated and normal molecules (“D/H ratios”) in disks evolve in a similar way as in molecular clouds. Fractionation is caused by rapid exchange reactions that are exothermic because of energy differences between deuterated and normal species. In the midplane region, where molecules are heavily depleted onto grain surfaces, the D/H ratios of gaseous molecules are higher than at larger heights. The D/H ratios for the vertical column densities of NH3, H2O, and HCO are sensitive to the temperature, and decrease significantly with decreasing radial distance for R ∼< 300 AU. The analogous D/H ratios for CH4 and H2CO, on the other hand, are not very sensitive to the temperature in the range (T = 10 − 50 K) we are concerned with, and do not decrease with decreasing R at R ≥ 50 AU. The D/H column-density ratios also depend on disk mass. In a disk with a larger mass, the ratios of deuterated species to normal species are higher, because of heavier depletion of molecules onto grains. In the second part of the paper, we report molecular column densities for disks embedded in ambient cloud gas. Our results suggest that CN and HCO can be tracers of gaseous disks, especially if the central object is a strong X-ray source . Our results also suggest that the radial distributions of CN, C2H, HCN, and H2CO may vary among disks depending on the X-ray luminosity of the central star. Accepted by A&A http://nova.planet.sci.kobe-u.ac.jp/∼aikawa/paper list.html The Mass-Velocity and Position-Velocity Relations in Episodic Outflows Héctor G. Arce & Alyssa A. Goodman 1 Harvard–Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA E-mail contact: harce@cfa.harvard.edu, agoodman@cfa.harvard.edu While observational evidence for the episodic nature of young stellar outflows continues to mount, existing numerical and theoretical models of molecular outflows assume they are formed by the interaction of a non-episodic wind from a young stellar object with an ambient cloud. In this Letter we estimate and discuss the effects of episodicity on the mass-velocity and position-velocity relations observed in molecular outflows. We explain how many recent observational results disagree with the predictions of non-episodic outflow models, and we offer simple explanations for the discrepancies. In particular, we discuss how an episodic stellar outflow can steepen the power-law slope of the mass-velocity relation in a molecular outflow. And, we illustrate how an episodic outflow can produce multiple “Hubble-wedges” in the position-velocity distribution of a molecular outflow. With a little more information than we have now, it may be possible to use the “fossil record” embedded in a molecular outflow’s mass-velocity and position-velocity relations to reconstruct the history of a young stellar object’s mass ejection episodes.

The results of a deep mid-IR ISOCAM survey of the L1551 dark molecular cloud are presented. The aim of this survey is a search for new YSO (Young Stellar Object) candidates, using two broad-band filters centred at 6.7 and 14.3 micron. Although two regions close to the centre of L1551 had to be avoided due to saturation problems, 96 sources were detected in total (76 sources at 6.7 micron and 44 sources at 14.3 micron). Using the 24 sources detected in both filters, 14 were found to have intrinsic mid-IR excess at 14.3 micron and were therefore classified as YSO candidates. Using additional observations in B, V, I, J, H and K obtained from the ground, most candidates detected at these wavelengths were confirmed to have mid-IR excess at 6.7 micron as well, and three additional YSO candidates were found. Prior to this survey only three YSOs were known in the observed region (avoiding L1551 IRS5/NE and HL/XZ Tau). This survey reveals 15 new YSO candidates, although several of these are uncertain due to their extended nature either in the mid-IR or in the optical/near-IR observations. Two of the sources with mid-IR excess are previously known YSOs, one is a brown dwarf MHO 5 and the other is the well known T Tauri star HH30, consisting of an outflow and an optically thick disk seen edge on.

We present results from an ISOCAM survey in the two broad band filters LW2 (5−8.5 µm) and LW3 (12−18 µm) of a 0.13 square degree coverage of the Serpens Main Cloud Core. A total of 392 sources were detected in the 6.7 µ mb and and 139 in the 14.3 µm band to a limiting sensitivity of ∼2 mJy. We identified 53 Young Stellar Objects (YSOs) with mid-IR excess from the single colour index (14.3/6.7), and 8 additional YSOs from the H − K/K − m6.7 diagram. Only 32 of these 61 sources were previously known to be YSO candidates. Only about 50% of the mid-IR excess sources show excesses in the near-IR J − H/H − K diagram. In the 48 square arcmin field covering the central Cloud Core the Class I/Class II number ratio is 19/18, i.e. about 10 times larger than in other young embedded clusters such as ρ Ophiuchi or Chamaeleon. The mid-IR fluxes of the Class I and flat-spectrum sources are found to be on the average larger than those of Class II sources. Stellar luminosities are estimated for the Class II sample, and its luminosity function is compatible with a coeval population of about 2 Myr which follows a three segment power-law IMF. For this age about 20% of the Class IIs are found to be young brown dwarf candidates. The YSOs are in general strongly clustered, the Class I sources more than the Class II sources, and there is an indication of sub-clustering. The sub-clustering of the protostar candidates has a spatial scale of 0.12 pc. These sub-clusters are found along the NW−SE oriented ridge and in very good agreement with the location of dense cores traced by millimeter data. The smallest clustering scale for the Class II sources is about 0.25 pc, similar to what was found for ρ Ophiuchi. Our data show evidence that star formation in Serpens has proceeded in several phases, and that a "microburst" of star formation has taken place very recently, probably within the last 105 yrs.

We present profile measurements of key constituents relevant to stratospheric chemistry and dynamics such as ozone (O 3 ), nitrous oxide (N 2 O), and chlorine monoxide (ClO) taken during the 2002–03 northern hemisphere winter by the Odin Sub‐Millimetre Radiometer (SMR), a limb‐sounding satellite sensor launched in February 2001. The observations of the chemically passive tracer N 2 O show a subsidence of lower stratospheric air masses inside the Arctic vortex in the range of 3–5 km, or 60–100 K in terms of potential temperature, for the period November 2002 to March 2003. Activated chlorine in the form of ClO was observed inside the vortex from the beginning of December until mid‐February. The accumulated chemical ozone loss over this period, derived from the correlation of ozone with N 2 O, is estimated to be 28 ± 9% on the 50 ppbv level of N 2 O, i.e., for lower stratospheric air masses subsiding from ∼23 down to 19 km, the lower limit of the Odin/SMR ozone measurement in the 501.8 GHz band.

We present results from an ISOCAM survey in the two broad band filters LW2 (5-8.5 mum) and LW3 (12-18 mum) of a 0.13 square degree coverage of the Serpens Main Cloud Core. A total of 392 sources were detected in the 6.7 mum band and 139 in the 14.3 mum band to a limiting sensitivity of similar to2 mJy. We identified 53 Young Stellar Objects (YSOs) with mid-IR excess from the single colour index [14.3/6.7], and 8 additional YSOs from the H - K/K - m(6,7) diagram. Only 32 of these 61 sources were previously known to be YSO candidates. Only about 50% of the mid-IR excess sources show excesses in the near-IR J - H/H - K diagram. In the 48 square arcmin field covering the central Cloud Core the Class I/Class II number ratio is 19/18, i.e. about 10 times larger than in other young embedded clusters such as rho Ophiuchi or Chamaeleon. The mid-IR fluxes of the Class I and flat-spectrum sources are found to be on the average larger than those of Class II sources. Stellar luminosities are estimated for the Class II sample, and its luminosity function is compatible with a coeval population of about 2 Myr which follows a three segment power-law IMF. For this age about 20% of the Class Its are found to be young brown dwarf candidates. The YSOs are in general strongly clustered, the Class I sources more than the Class 11 sources, and there is an indication of sub-clustering. The sub-clustering of the protostar candidates has a spatial scale of 0.12 pc. These sub-clusters are found along the NW-SE oriented ridge and in very good agreement with the location of dense cores traced by millimeter data. The smallest clustering scale for the Class II sources is about 0.25 pc, similar to what was found for rho Ophiuchi. Our data show evidence that star formation in Serpens has proceeded in several phases, and that a "microburst" of star formation has taken place very recently, probably within the last 10(5) yrs.

A simulator for phacoemulsification cataract extraction is developed. A three dimensional visual interface and foot pedals for phacoemulsification power, x-y positioning, zoom and focus were established. An algorithm that allows real time visual feedback of the surgical field was developed. Cataract surgery is the most common surgical procedure. The operation requires input from both feet and both hands and provides visual feedback through the operation microscope essentially without tactile feedback. Experience demonstrates that the number of complications for an experienced surgeon learning phacoemulsification, decreases exponentially, reaching close to the asymptote after the first 500 procedures despite initial wet lab training on animal eyes. Simulator training is anticipated to decrease training time, decrease complication rate for the beginner and reduce expensive supervision by a high volume surgeon.

The optical spectrograph and infrared imager system (OSIRIS) on board the Odin spacecraft is designed to retrieve altitude profiles of terrestrial atmospheric minor species by observing limb-radiance profiles. The grating optical spectrograph (OS) obtains spectra of scattered sunlight over the range 280–800 nm with a spectral resolution of approximately 1 nm. The Odin spacecraft performs a repetitive vertical limb scan to sweep the OS 1 km vertical field of view over selected altitude ranges from approximately 10 to 100 km. The terrestrial absorption features that are superimposed on the scattered solar spectrum are monitored to derive the minor species altitude profiles. The spectrograph also detects the airglow, which can be used to study the mesosphere and lower thermosphere. The other part of OSIRIS is a three-channel infrared imager (IRI) that uses linear array detectors to image the vertical limb radiance over an altitude range of approximately 100 km. The IRI observes both scattered sunlight and the airglow emissions from the oxygen infrared atmospheric band at 1.27 µm and the OH (3-1) Meinel band at 1.53 µm. A tomographic inversion technique is used with a series of these vertical images to derive the two-dimensional distribution of the emissions within the orbit plane. PACS Nos.: 07.05.Pj, 07.60.Dq, 07.60.Rd, 07.87, 94.10.Dy, 94.10.Fa, 94.10.Gb, 94.10.Rk

We present ISOCAM observations (5-18 mum) of the Horsehead nebula, together with observations of the (J = 1-0) and (J = 2-1) transitions of (CO)-C-12, (CO)-C-13 and (CO)-O-18 taken at the IRAM 30-m telescope.The Horsehead nebula presents a typical photodissociation region illuminated by the O9.5 V system sigma Ori. The ISOCAM emission is due to very small particles transiently heated to high temperature each time they absorb a UV photon. A very sharp filament (width: similar to10" or similar to0.02 pc) is detected by ISOCAM at the illuminated edge of the nebula. This filament is due to a combined effect of steep increase of the column density and extinction of incident radiation, on typical sizes below similar to0.01 pc. Both the three-dimensional shape and the local density of the illuminated interface are strongly constrained. The dense material forming the edge of the Horsehead nebula appears illuminated edge-on by sigma Ori, and the particles located beyond the border should not be affected by the incident radiation field. This structure may be due to dense filaments in the parental cloud which have shielded the material located in their shadow from the photo-dissociating radiations.The measurement of the penetration depth of the incident radiation from the infrared data (similar to0.01 pc) gives a density of a few 10(4) cm(-3) just behind the bright filament. This value is comparable to the estimate of the density beyond the edge and deduced from our molecular observations, and also to the density behind the ionization front calculated in the stationary case. The material behind the illuminated edge could also be non-homogeneous, with clump sizes significantly smaller than the observed penetration depth of similar to0.01 pc. In that case no upper limit on the average density just behind the illuminated edge can be given.