Dense and warm molecular gas in the envelopes and outflows of southern low-mass protostars

Observations of dense molecular gas lie at the basis of our understanding of the density and temperature structure of protostellar envelopes and molecular outflows. We aim to characterize the properties of the protostellar envelope, molecular outflow and surrounding cloud, through observations of high excitation molecular lines within a sample of 16 southern sources presumed to be embedded YSOs. Observations of submillimeter lines of CO, HCO+ and their isotopologues, both single spectra and small maps were taken with the FLASH and APEX-2a instruments mounted on APEX to trace the gas around the sources. The HARP-B instrument on the JCMT was used to map IRAS 15398-3359 in these lines. HCO+ mapping probes the presence of dense centrally condensed gas, a characteristic of protostellar envelopes. The rare isotopologues C18O and H13CO+ are also included to determine the optical depth, column density, and source velocity. The combination of multiple CO transitions, such as 3-2, 4-3 and 7-6, allows to constrain outflow properties, in particular the temperature. Archival submillimeter continuum data are used to determine envelope masses. Eleven of the sixteen sources have associated warm and/or dense quiescent as characteristic of protostellar envelopes, or an associated outflow. Using the strength and degree of concentration of the HCO+ 4-3 and CO 4-3 lines as a diagnostic, five sources classified as Class I based on their spectral energy distributions are found not to be embedded YSOs. The C18O 3-2 lines show that for none of the sources, foreground cloud layers are present. Strong molecular outflows are found around six sources, .. (continued in paper)Comment: Accepted by A&A, 13 figure

Gender-specific changes in quality of life following cardiovascular disease: a prospective study

Gender-specific changes in Quality of Life (QoL) following cardiovascular disease (CVD) were studied in 208 patients to determine whether gender-related differences in postmorbid QoL result from differences in disease severity, premorbid QoL, or different CVD-related recovery. Premorbid data were available from a community-based survey. Follow-ups were done at 6 weeks, 6 months, and 12 months after diagnosis. Results showed that females had worse QoL at all three postmorbid assessments compared to males. However, multivariate analyses adjusting for premorbid gender differences and disease severity showed no significant gender-related differences for physical and psychologic, functioning. Therefore, gender differences in QoL following CVD mainly result from premorbid differences in QoL, age, comorbidity, and disease severity at the time of diagnosis, and do not appear to be the consequence of gender-specific recovery. However, in clinical practice it is important to acknowledge the poorer QoL of females following CVD. (C) 2002 Elsevier Science. All rights reserve

Changes in health-related quality of life in older patients with acute myocardial infarction or congestive heart failure: a prospective study

OBJECTIVES: To study changes in health-related quality of life (HR-QL) following acute myocardial infarction (AMI) or congestive heart failure (CHF) in older people (greater than or equal to 57 yr).DESIGN: Prospective cohort Study.SETTING: Primary healthcare registers.PARTICIPANTS: Patients were enrolled on the basis of primary healthcare records. Eighty-nine AMI patients (mean age = 69.5) and 119 CHF patients (mean age = 74.5) were included for analysis.MEASUREMENTS: HR-QL was conceptualized and measured by means of physical (activities of daily living (ADL), instrumental activities of daily living (IADL)), psychological (depressive symptoms, anxiety), social, and role functioning. Premorbid data (TO) were available from a 1993 community-based survey. Incident AMI and CHF cases, developed after 1993, were prospectively followed for 12 months. Assessments were performed at 6 weeks (T1) and 6 (T2) and 12 months (T3) after diagnosis.RESULTS: At the premorbid assessment, AMI patients did not significantly differ on HR-QL from a reference group of older people, whereas CHF patients were on average older and had worse HR-QL compared to the reference group. Although CHF had not yet been diagnosed at TO, symptoms were already present and resulted in decreased levels of functioning. At T1, all HR-QL measures showed worse functioning compared with TO, except for depressive symptoms that presented later (at T2). In contrast to the delay in depressive symptoms, a significant increase in anxiety was already seen at T1. The effect of the somatic conditions was the largest on physical functioning. Effects on psychological and social functioning were less pronounced but still significant. Effects were maintained during the 12 months of follow-up.CONCLUSION: The negative consequences on HR-QL in both AMI and CHF patients are not temporary. No recovery of function was seen in AMI patients, and functioning and CHF patients continued to decline in the first year after diagnosis

APEX-CHAMP+ high-J CO observations of low-mass young stellar objects: II. Distribution and origin of warm molecular gas

The origin and heating mechanisms of warm (50<T<200 K) molecular gas in low-mass young stellar objects (YSOs) are strongly debated. Both passive heating of the inner collapsing envelope by the protostellar luminosity as well as active heating by shocks and by UV associated with the outflows or accretion have been proposed. We aim to characterize the warm gas within protosteller objects, and disentangle contributions from the (inner) envelope, bipolar outflows and the quiescent cloud. High-J CO maps (12CO J=6--5 and 7--6) of the immediate surroundings (up to 10,000 AU) of eight low-mass YSOs are obtained with the CHAMP+ 650/850 GHz array receiver mounted on the APEX telescope. In addition, isotopologue observations of the 13CO J=6--5 transition and [C I] 3P_2-3P_1 line were taken. Strong quiescent narrow-line 12CO 6--5 and 7--6 emission is seen toward all protostars. In the case of HH~46 and Ced 110 IRS 4, the on-source emission originates in material heated by UV photons scattered in the outflow cavity and not just by passive heating in the inner envelope. Warm quiescent gas is also present along the outflows, heated by UV photons from shocks. Shock-heated warm gas is only detected for Class 0 flows and the more massive Class I sources such as HH~46. Outflow temperatures, estimated from the CO 6--5 and 3--2 line wings, are ~100 K, close to model predictions, with the exception of the L~1551 IRS 5 and IRAS 12496-7650, for which temperatures <50 K are found. APEX-CHAMP+ is uniquely suited to directly probe a protostar's feedback on its accreting envelope gas in terms of heating, photodissociation, and outflow dispersal by mapping 1'x1' regions in high-J CO and [C I] lines.Comment: 18 pages, accepted by A&A, A version with the figures in higher quality can be found on my website: http://www.cfa.harvard.edu/~tvankemp

APEX-CHAMP+ high-J CO observations of low-mass young stellar objects: III. NGC 1333 IRAS 4A/4B envelope, outflow and UV heating

NGC 1333 IRAS 4A and IRAS 4B sources are among the best studied Stage 0 low-mass protostars which are driving prominent bipolar outflows. Most studies have so far concentrated on the colder parts (T<30K) of these regions. The aim is to characterize the warmer parts of the protostellar envelope in order to quantify the feedback of the protostars on their surroundings in terms of shocks, UV heating, photodissociation and outflow dispersal. Fully sampled large scale maps of the region were obtained; APEX-CHAMP+ was used for 12CO 6-5, 13CO 6-5 and [CI] 2-1, and JCMT-HARP-B for 12CO 3-2 emissions. Complementary Herschel-HIFI and ground-based lines of CO and its isotopologs, from 1-0 upto 10-9 (Eu/k 300K), are collected at the source positions. Radiative-transfer models of the dust and lines are used to determine temperatures and masses of the outflowing and UV-heated gas and infer the CO abundance structure. Broad CO emission line profiles trace entrained shocked gas along the outflow walls, with typical temperatures of ~100K. At other positions surrounding the outflow and the protostar, the 6-5 line profiles are narrow indicating UV excitation. The narrow 13CO 6-5 data directly reveal the UV heated gas distribution for the first time. The amount of UV-heated and outflowing gas are found to be comparable from the 12CO and 13CO 6-5 maps, implying that UV photons can affect the gas as much as the outflows. Weak [CI] emission throughout the region indicates a lack of CO dissociating photons. Modeling of the C18O lines indicates the necessity of a "drop" abundance profile throughout the envelope where the CO freezes out and is reloaded back into the gas phase, thus providing quantitative evidence for the CO ice evaporation zone around the protostars. The inner abundances are less than the canonical value of CO/H_2=2.7x10^-4, indicating some processing of CO into other species on the grains.Comment: 20 pages, 22 figures, Accepted by A&

Feshbach Spectroscopy of a Shape Resonance

We present a new spectroscopy technique for studying cold-collision properties. The technique is based on the association and dissociation of ultracold molecules using a magnetically tunable Feshbach resonance. The energy and lifetime of a shape resonance are determined from a measurement of the dissociation rate. Additional spectroscopic information is obtained from the observation of a spatial interference pattern between an outgoing s wave and d wave. The experimental data agree well with the results from a new model, in which the dissociation process is connected to a scattering gedanken experiment, which is analyzed using a coupled-channels calculation.Comment: Introduction rewritte