Behavior of Free Electrons toward Gas Molecules

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The Abundance of Elements in Cool Stars, as Determined from High-Resolution, 1-5 Micron Spectroscopy

We review the field of abundance determinations of elements in cool stars, with special interest paid to determinations based on analyses of high-resolution, 1-5 micron spectra. We discuss the current status, problems, and challenges of exploring high-resolution, near-infrared spectra. In particular, advantages and drawbacks are pointed out. A few examples of current, chemical-abundance determinations are high-lighted and, finally, we discuss the developmentComment: To appear in the proceedings of the ESO Workshop on High Resolution Infrared Spectroscopy in Astronomy held in Garching, Germany, 18-21 November 200

Association between laparoscopic antireflux surgery and recurrence of gastroesophageal reflux

IMPORTANCE: Cohort studies, mainly based on questionnaires and interviews, have reported high rates of reflux recurrence after antireflux surgery, which may have contributed to a decline in its use. Reflux recurrence after laparoscopic antireflux surgery has not been assessed in a long-term population-based study of unselected patients. OBJECTIVES: To determine the risk of reflux recurrence after laparoscopic antireflux surgery and to identify risk factors for recurrence. DESIGN AND SETTING: Nationwide population-based retrospective cohort study in Sweden between January 1, 2005, and December 31, 2014, based on all Swedish health care and including 2655 patients who underwent laparoscopic antireflux surgery according to the Swedish Patient Registry. Their records were linked to the Swedish Causes of Death Registry and Prescribed Drug Registry. EXPOSURES: Primary laparoscopic antireflux surgery due to gastroesophageal reflux disease in adults (>18 years). MAIN OUTCOMES AND MEASURES: The outcomewas recurrence of reflux, defined as use of antireflux medication (proton pump inhibitors or histamine2 receptor antagonists for >6 months) or secondary antireflux surgery. Multivariable Cox regression was used to assess risk factors for reflux recurrence. RESULTS: Among all 2655 patients who underwent antireflux surgery (median age, 51.0 years; interquartile range, 40.0-61.0 years; 1354 men [51.0%]) and were followed up for a median of 5.6 years, 470 patients (17.7%) had reflux recurrence; 393 (83.6%) received long-term antireflux medication and 77 (16.4%) underwent secondary antireflux surgery. Risk factors for reflux recurrence included female sex (hazard ratio [HR], 1.57 [95%CI, 1.29-1.90]; 286 of 1301 women [22.0%] and 184 of 1354 men [13.6%] had recurrence of reflux), older age (HR, 1.41 [95%CI, 1.10-1.81] for age 61 years compared with 45 years; recurrence among 156 of 715 patients and 133 of 989 patients, respectively), and comorbidity (HR, 1.36 [95%CI, 1.13-1.65] for Charlson comorbidity index score 1 compared with 0; recurrence among 180 of 804 patients and 290 of 1851 patients, respectively). Hospital volume of antireflux surgery was not associated with risk of reflux recurrence (HR, 1.09 [95%CI, 0.77-1.53] for hospital volume 24 surgeries compared with 76 surgeries; recurrence among 38 of 266 patients [14.3%] and 271 of 1526 patients [17.8%], respectively). CONCLUSIONS AND RELEVANCE: Among patients who underwent primary laparoscopic antireflux surgery, 17.7%experienced recurrent gastroesophageal reflux requiring long-term medication use or secondary antireflux surgery. Risk factors for recurrence were older age, female sex, and comorbidity. Laparoscopic antireflux surgery was associated with a relatively high rate of recurrent gastroesophageal reflux disease requiring treatment, diminishing some of the benefits of the operation.Swedish Research Council, D0547801Publishe

Effect of an organizational change in a prehospital trauma care protocol and trauma transport directive in a large urban city : a before and after study

Background: Trauma systems and regionalized trauma care have been shown to improve outcome in severely injured trauma patients. The aim of this study was to evaluate the implementation of a prehospital trauma care protocol and transport directive, and to determine its effects on the number of primary admissions and secondary trauma transfers in a large Scandinavian city. Methods: We performed a retrospective observational study based on local trauma registries and hospital and ambulance records in Stockholm County; patients > 15 years of age with an Injury Severity Score (ISS) > 15 transported to any emergency care hospitals in the Stockholm area were included for the years 2006 and 2008. We also included secondary transferred patients to the regional trauma center during 2006, 2008, and 2013. Results: A total of 693 primarily admitted trauma patients were included for the years 2006 and 2008. For the years 2006, 2008 and 2013, we included 114 secondarily transported trauma patients. The number of primary patient transports to the trauma center increased during the years by 20.2 %, (p <0.001); patients primarily transported to the trauma center had a significantly higher Injury Severity Score in 2008 than in 2006, and the number of patients transported secondarily to the trauma center in 2006 was higher compared to 2008 and to 2013 (p <0.001, all 3 years). Discussion: Our data indicate that implementation of a prehospital trauma care protocol may have an effect on transportation of severely injured trauma patients. A decrease in secondarily transported trauma patients to the regional trauma center was noted after 1 year and persisted at 7 years after the organizational change. Patients primarily admitted to the trauma center after the change had more severe injuries than patients transported to other emergency hospitals in the area even if 20 % of patients were not admitted primarily to a trauma center. This does not imply that the transport directives or the criteria were not followed but rather reveals the difficulties and uncertainties of field triage. Conclusions: With the introduction of a prehospital trauma transport directive in a large urban city, an increase in patients transported to the regional trauma center and a decrease in secondary transfers were detected, but a considerable number of severely injured patients were still transported to local hospitals.Peer reviewe

POLLUX : a database of synthetic stellar spectra

Synthetic spectra are needed to determine fundamental stellar and wind parameters of all types of stars. They are also used for the construction of theoretical spectral libraries helpful for stellar population synthesis. Therefore, a database of theoretical spectra is required to allow rapid and quantitative comparisons to spectroscopic data. We provide such a database offering an unprecedented coverage of the entire Hertzsprung-Russell diagram. We present the POLLUX database of synthetic stellar spectra. For objects with Teff < 6 000 K, MARCS atmosphere models are computed and the program TURBOSPECTRUM provides the synthetic spectra. ATLAS12 models are computed for stars with 7 000 K <Teff <15 000 K. SYNSPEC gives the corresponding spectra. Finally, the code CMFGEN provides atmosphere models for the hottest stars (Teff > 25 000 K). Their spectra are computed with CMF_FLUX. Both high resolution (R>150 000) optical spectra in the range 3 000 to 12 000 A and spectral energy distributions extending from the UV to near--IR ranges are presented. These spectra cover the HR diagram at solar metallicity. We propose a wide variety of synthetic spectra for various types of stars in a format that is compliant with the Virtual Observatory standards. A user--friendly web interface allows an easy selection of spectra and data retrieval. Upcoming developments will include an extension to a large range of metallicities and to the near--IR high resolution spectra, as well as a better coverage of the HR diagram, with the inclusion of models for Wolf-Rayet stars and large datasets for cool stars. The POLLUX database is accessible at http://pollux.graal.univ-montp2.fr/ and through the Virtual Observatory.Comment: 9 pages, 5 figures, accepted for publication in Astronomy ans Astrophysic

The Southern Ocean Observing System (SOOS)

[in “State of the Climate in 2014” : Special Supplement to the Bulletin of the American Meteorological Society Vol. 96, No. 7, July 2015

The puzzling dredge-up pattern in NGC 1978

Low-mass stars are element factories that efficiently release their products in the final stages of their evolution by means of stellar winds. Since they are large in number, they contribute significantly to the cosmic matter cycle. To assess this contribution quantitatively, it is crucial to obtain a detailed picture of the stellar interior, particularly with regard to nucleosynthesis and mixing mechanisms. We seek to benchmark stellar evolutionary models of low-mass stars. In particular, we measure the surface abundance of ^{12}C in thermally pulsing AGB stars with well-known mass and metallicity, which can be used to infer information about the onset and efficiency of the third dredge-up. We recorded high-resolution near-infrared spectra of AGB stars in the LMC cluster NGC 1978. The sample comprised both oxygen-rich and carbon-rich stars, and is well-constrained in terms of the stellar mass, metallicity, and age. We derived the C/O and ^{12}C/^{13}C ratio from the target spectra by a comparison to synthetic spectra. Then, we compared the outcomes of stellar evolutionary models with our measurements. The M stars in NGC 1978 show values of C/O and ^{12}C/^{13}C that can best be explained with moderate extra-mixing on the RGB coupled to a moderate oxygen enhancement in the chemical composition. These oxygen-rich stars do not seem to have undergone third dredge-up episodes (yet). The C stars show carbon-to-oxygen and carbon isotopic ratios consistent with the occurrence of the third dredge-up. We did not find S stars in this cluster. None of the theoretical schemes that we considered was able to reproduce the observations appropriately. Instead, we discuss some non-standard scenarios to explain the puzzling abundance pattern in NGC 1978.Comment: 16 pages, 9 figures, 4 tables, accepted for publication in A&A, language revise

Comparing the effect of STan (cardiotocographic electronic fetal monitoring (CTG) plus analysis of the ST segment of the fetal electrocardiogram) with CTG alone on emergency caesarean section rates: study protocol for the STan Australian Randomised controlled Trial (START).

BACKGROUND: Cardiotocography is almost ubiquitous in its use in intrapartum care. Although it has been demonstrated that there is some benefit from continuous intrapartum fetal monitoring using cardiotocography, there is also an increased risk of caesarean section which is accompanied by short-term and long-term risks to the mother and child. There is considerable potential to reduce unnecessary operative delivery with up to a 60% false positive diagnosis of fetal distress using cardiotocography alone. ST analysis of the fetal electrocardiogram is a promising adjunct to cardiotocography alone, and permits detection of metabolic acidosis of the fetus, potentially reducing false positive diagnosis of fetal distress. METHODS: This study will be a single-centre, parallel-group, randomised controlled trial, conducted over 3 years. The primary hypothesis will be that the proportion of women with an emergency caesarean section on ST analysis will not equal that for women on cardiotocography monitoring alone. Participants will be recruited at the Women's and Children's Hospital, a high-risk specialty facility with approximately 5000 deliveries per annum. A total of 1818 women will be randomised to the treatment or conventional arm with an allocation ratio of 1:1, stratified by parity. The primary outcome is emergency caesarean section (yes/no). Statistical analysis will follow standard methods for randomised trials and will be performed on an intention-to-treat basis. Secondary maternal and neonatal outcomes will also be analysed. Additional study outcomes include psychosocial outcomes, patient preferences and cost-effectiveness. DISCUSSION: Approximately 20% of Australian babies are delivered by emergency caesarean section. This will be the first Australian trial to examine ST analysis of the fetal electrocardiogram as an adjunct to cardiotocography as a potential method for reducing this proportion. The trial will be among the first to comprehensively examine ST analysis, taking into account the impact on psychosocial well-being as well as cost-effectiveness. This research will provide Australian evidence for clinical practice and guideline development as well as for policy-makers and consumers to make informed, evidence-based choices about care in labour. TRIAL REGISTRATION: ANZCTR, ACTRN1261800006268 . Registered on 19 January 2018