Mars atmospheric escape and isotopic fractionation: Synthesis of data and models

The present Mars atmosphere is relatively thin and cold. It is not at all like that which is presumed to have been responsible for the formation of valley networks and the heavy erosion of craters during the earliest epochs of martian history. An important goal of Mars exploration is to try to understand the properties of the early atmosphere, the initial inventory of volatiles at the planet's surface, the processes by which the atmosphere and climate have evolved over time, and the current location of volatiles presumed to have been in the atmosphere in the earlier times. The current status of understanding of the escape of volatiles to space over geologic time and the resulting fractionation of isotopes of stable atoms remaining in the atmosphere are described, and a scenario for volatile abundance and evolution that is consistent with the available information on the escape and fractionation of each species is constructed. In particular, the evolution of hydrogen, carbon, oxygen, and nitrogen, as contained in atmospheric (and non-atmospheric) water, carbon dioxide, and molecular nitrogen, is examined

Selection of pasture species for groundcover suited to shade in mature macadamia orchards in subtropical Australia

Soil erosion is a significant problem in subtropical macadamia orchards in Australia, especially when groundcover vegetation is shaded out under older orchards. The aim of this study was to identify suitable low-growing, perennial groundcovers that would persist in the low light conditions under mature macadamias. Twenty-six legume and grass accessions and 1 herb were evaluated in small plots in a 16-year-old commercial orchard near Lismore, NSW. Plant density, groundcover (%), herbage mass, sward canopy height and groundcover spread were determined in high, medium and low light in the interrow for 2 years (1996–97). Groundcover was also measured for 3 years, on 19 of the accessions in a younger orchard at another site. Dactyloctenium australe provided the best groundcover in both high and low light and met most other specifications for an ideal groundcover for macadamias. Other promising grass species included Paspalum mandiocanum, Panicum laxum and Microlaena stipoides cv. Wakefield. However, Paspalum mandiocanum has been cited as having potential weediness in subtropical Australia, and is not recommended as a groundcover for macadamias. The legumes generally did not perform as well in low light as grass species. However, Arachis pintoi cv. Amarillo and a sterile Arachis pintoi × Arachis repens hybrid provided highest percent groundcover in high and medium light. Further assessment of these species in larger plots to determine their establishment and persistence under heavy orchard traffic and suitability for mechanical harvest operations has commenced

Predictors and outcomes of crossover to surgery from physical therapy for meniscal tear and osteoarthritis a randomized trial comparing physical therapy and surgery

BACKGROUND: Arthroscopic partial meniscectomy (APM) combined with physical therapy (PT) have yielded pain relief similar to that provided by PT alone in randomized trials of subjects with a degenerative meniscal tear. However, many patients randomized to PT received APM before assessment of the primary outcome. We sought to identify factors associated with crossing over to APM and to compare pain relief between patients who had crossed over to APM and those who had been randomized to APM. METHODS: We used data from the MeTeOR (Meniscal Tear in Osteoarthritis Research) Trial of APM with PT versus PT alone in subjects ≥45 years old who had mild-to-moderate osteoarthritis and a degenerative meniscal tear. We assessed independent predictors of crossover to APM among those randomized to PT. We also compared pain relief at 6 months among those randomized to PT who crossed over to APM, those who did not cross over, and those originally randomized to APM. RESULTS: One hundred and sixty-four subjects were randomized to and received APM and 177 were randomized to PT, of whom 48 (27%) crossed over to receive APM in the first 140 days after randomization. In multivariate analyses, factors associated with a higher likelihood of crossing over to APM among those who had originally been randomized to PT included a baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain Score of ≥40 (risk ratio [RR] = 1.99; 95% confidence interval [CI] = 1.00, 3.93) and symptom duration of <1 year (RR = 1.74; 95% CI = 0.98, 3.08). Eighty-one percent of subjects who crossed over to APM and 82% of those randomized to APM had an improvement of ≥10 points in their pain score at 6 months, as did 73% of those who were randomized to and received only PT. CONCLUSIONS: Subjects who crossed over to APM had presented with a shorter symptom duration and greater baseline pain than those who did not cross over from PT. Subjects who crossed over had rates of surgical success similar to those of the patients who had been randomized to surgery. Our findings also suggest that an initial course of rigorous PT prior to APM may not compromise surgical outcome. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence

Solar Flare Intermittency and the Earth's Temperature Anomalies

We argue that earth's short-term temperature anomalies and the solar flare intermittency are linked. The analysis is based upon the study of the scaling of both the spreading and the entropy of the diffusion generated by the fluctuations of the temperature time series. The joint use of these two methods evidences the presence of a L\'{e}vy component in the temporal persistence of the temperature data sets that corresponds to the one that would be induced by the solar flare intermittency. The mean monthly temperature datasets cover the period from 1856 to 2002.Comment: 4 pages, 5 figure

Financial Analysis of Dalbavancin for Acute Bacterial Skin and Skin Structure Infections for Self-Pay Patients

© 2020, The Author(s). Introduction: Acute bacterial skin and skin structure infections (ABSSSI) are an increasing cause of admission in the self-pay population. We previously reported that patients with ABSSSI discharged to receive dalbavancin showed a decreased length of stay (LOS) and total direct costs without increasing 30-day readmission rate. For patients who are financially eligible, a dalbavancin vial replacement program can offset costs. The objective of this study was to determine cost differences in treating ABSSSI in self-pay inpatients discharged to receive dalbavancin compared to standard of care (SOC). Methods: This retrospective cohort within a community health system compared self-pay adult inpatients with ABSSSI from February 3, 2016 to August 5, 2019 discharged to receive dalbavancin at an outpatient infusion center with SOC intravenous antibiotics. Patients were included with cellulitis, abscess, or postoperative wound infections diagnoses on the basis of International Classification of Disease, Tenth Revision (ICD-10) codes. Excluded populations were patients without dalbavancin vial replacement performed, pregnant, infections caused exclusively by gram-negative bacteria or fungi, or ICD-10 codes not consistent with ABSSSI. The primary outcome was direct cost of hospital stay. Secondary outcomes included length of stay (LOS), 30-day readmission rates, adverse events (AE), and indirect hospital costs. On the basis of previous studies, a one-sided Student’s t test was performed on financial data. Results: Twelve dalbavancin and 263 SOC patients met inclusion criteria. Direct cost ($2758 vs$4010, p = 0.105) and indirect hospital cost ($2913 vs$3646 , p = 0.162) per patient were less in the dalbavancin group. There was no significant difference between median LOS (4 vs 4, p = 0.888), AE (0% vs 14.8%), and 30-day readmission rates for dalbavancin vs SOC group (8.3% vs 7.2%, p = 0.604). Conclusion: Self-pay patients with ABSSSI discharged to receive dalbavancin with vial replacement resulted in decreased direct and indirect costs per patient with similar 30-day readmission rates, AE, and LOS. More studies targeted toward this population are warranted to determine ultimate benefit

Spectroscopy of Brown Dwarf Candidates in the rho Ophiuchi Molecular Core

We present an analysis of low resolution infrared spectra for 20 brown dwarf candidates in the core of the $\rho$ Ophiuchi molecular cloud. Fifteen of the sources display absorption-line spectra characteristic of late-type stars. By comparing the depths of water vapor absorption bands in our candidate objects with a grid of M dwarf standards, we derive spectral types which are independent of reddening. Optical spectroscopy of one brown dwarf candidate confirms the spectral type derived from the water bands. Combining their spectral types with published near-infrared photometry, effective temperatures and bolometric stellar luminosities are derived enabling us to place our sample on the Hertzsprung-Russell diagram. We compare the positions of the brown dwarf candidates in this diagram with two sets of theoretical models in order to estimate their masses and ages. Considering uncertainties in placing the candidates in the H-R diagram, six objects consistently lie in the brown dwarf regime and another five objects lie in the transition region between stellar and substellar objects. The ages inferred for the sample are consistent with those derived for higher mass association members. Three of the newly identified brown dwarfs display infrared excesses at $\lambda$=2.2 $\mu$m suggesting that young brown dwarfs can have active accretion disks. Comparing our mass estimates of the brown dwarf candidates with those derived from photometric data alone suggests that spectroscopy is an essential component of investigations of the mass functions of young clusters.Comment: Astronomical Journal, in press: 25 pages, latex, 5 tables and 6 figures (separate

3,4-O-Isopropyl­idene-2-C-methyl-d-galactonolactone

X-ray crystallography unequivocally confirmed the stereochemistry of the 2-C-methyl group in the title mol­ecule, C10H16O6, in which the 1,5-lactone ring exists in a boat conformation. The use of d-galactose in the synthesis determined the absolute stereochemistry. The crystal exists as O—H⋯O hydrogen-bonded layers in the ab plane, with each mol­ecule acting as a donor and acceptor for two hydrogen bonds

Experimental and theoretical investigation of the triple differential cross section for electron impact ionization of pyrimidine molecules

Cross-section data for electron impact induced ionization of bio-molecules are important for modelling the deposition of energy within a biological medium and for gaining knowledge of electron driven processes at the molecular level. Triply differential cross sections have been measured for the electron impact ionization of the outer valence 7b2 and 10a1 orbitals of pyrimidine, using the (e, 2e) technique. The measurements have been performed with coplanar asymmetric kinematics, at an incident electron energy of 250 eV and ejected electron energy of 20 eV, for scattered electron angles of −5°, −10°, and −15°. The ejected electron angular range encompasses both the binary and recoil peaks in the triple differential cross section. Corresponding theoretical calculations have been performed using the molecular 3-body distorted wave model and are in reasonably good agreement with the present experiment