r-Process Lanthanide Production and Heating Rates in Kilonovae

r-Process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. (2013, ApJ, 774, 25) and Tanaka & Hotokezaka (2013, ApJ, 775, 113) pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions $Y_e$, initial specific entropies $s$, and expansion timescales $\tau$. We find that the ejecta is lanthanide-free for $Y_e \gtrsim 0.22 - 0.30$, depending on $s$ and $\tau$. The heating rate is insensitive to $s$ and $\tau$, but certain, larger values of $Y_e$ lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing $Y_e$, but the light curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and $100\,\text{days}$, and we provide a simple fit in $Y_e$, $s$, and $\tau$ to estimate whether the ejecta is lanthanide-rich or not.Comment: 19 pages, 9 figure

SkyNet: A modular nuclear reaction network library

Almost all of the elements heavier than hydrogen that are present in our solar system were produced by nuclear burning processes either in the early universe or at some point in the life cycle of stars. In all of these environments, there are dozens to thousands of nuclear species that interact with each other to produce successively heavier elements. In this paper, we present SkyNet, a new general-purpose nuclear reaction network that evolves the abundances of nuclear species under the influence of nuclear reactions. SkyNet can be used to compute the nucleosynthesis evolution in all astrophysical scenarios where nucleosynthesis occurs. SkyNet is free and open-source and aims to be easy to use and flexible. Any list of isotopes can be evolved and SkyNet supports various different types of nuclear reactions. SkyNet is modular so that new or existing physics, like nuclear reactions or equations of state, can easily be added or modified. Here, we present in detail the physics implemented in SkyNet with a focus on a self-consistent transition to and from nuclear statistical equilibrium (NSE) to non-equilibrium nuclear burning, our implementation of electron screening, and coupling of the network to an equation of state. We also present comprehensive code tests and comparisons with existing nuclear reaction networks. We find that SkyNet agrees with published results and other codes to an accuracy of a few percent. Discrepancies, where they exist, can be traced to differences in the physics implementations.Comment: 39 pages, 11 figures, published in ApJ Supplement Serie

Medical treatment of vertebral osteoporosis

Although osteoporosis is a systemic disease, vertebral fractures due to spinal bone loss are a frequent, sometimes early and often neglected complication of the disease, generally associated with considerable disability and pain. As osteoporotic vertebral fractures are an important predictor of future fracture risk, including at the hip, medical management is targeted at reducing fracture risk. A literature search for randomized, double-blind, prospective, controlled clinical studies addressing medical treatment possibilities of vertebral fractures in postmenopausal Caucasian women was performed on the leading medical databases. For each publication, the number of patients with at least one new vertebral fracture and the number of randomized patients by treatment arm was retrieved. The relative risk (RR) and the number needed to treat (NNT, i.e. the number of patients to be treated to avoid one radiological vertebral fracture over the duration of the study), together with the respective 95% confidence intervals (95%CI) were calculated for each study. Treatment of steroid-induced osteoporosis and treatment of osteoporosis in men were reviewed separately, based on the low number of publications available. Forty-five publications matched with the search criteria, allowing for analysis of 15 different substances tested regarding their anti-fracture efficacy at the vertebral level. Bisphosphonates, mainly alendronate and risedronate, were reported to have consistently reduced the risk of a vertebral fracture over up to 50 months of treatment in four (alendronate) and two (risedronate) publications. Raloxifene reduced vertebral fracture risk in one study over 36 months, which was confirmed by 48 months' follow-up data. Parathormone (PTH) showed a drastic reduction in vertebral fracture risk in early studies, while calcitonin may also be a treatment option to reduce fracture risk. For other substances published data are conflicting (calcitriol, fluoride) or insufficient to conclude about efficacy (calcium, clodronate, etidronate, hormone replacement therapy, pamidronate, strontium, tiludronate, vitamin D). The low NNTs for the leading substances (ranges: 15-64 for alendronate, 8-26 for risedronate, 23 for calcitonin and 28-31 for raloxifene) confirm that effective and efficient drug interventions for treatment and prevention of osteoporotic vertebral fractures are available. Bisphosphonates have demonstrated similar efficacy in treatment and prevention of steroid-induced and male osteoporosis as in postmenopausal osteoporosis. The selection of the appropriate drug for treatment of vertebral osteoporosis from among a bisphosphonate (alendronate or risedronate), PTH, calcitonin or raloxifene will mainly depend on the efficacy, tolerability and safety profile, together with the patient's willingness to comply with a long-term treatment. Although reduction of vertebral fracture risk is an important criterion for decision making, drugs with proven additional fracture risk reduction at all clinically relevant sites (especially at the hip) should be the preferred option

EC-GSM-IoT Network Synchronization with Support for Large Frequency Offsets

EDGE-based EC-GSM-IoT is a promising candidate for the billion-device cellular IoT (cIoT), providing similar coverage and battery life as NB-IoT. The goal of 20 dB coverage extension compared to EDGE poses significant challenges for the initial network synchronization, which has to be performed well below the thermal noise floor, down to an SNR of -8.5 dB. We present a low-complexity synchronization algorithm supporting up to 50 kHz initial frequency offset, thus enabling the use of a low-cost +/-25 ppm oscillator. The proposed algorithm does not only fulfill the 3GPP requirements, but surpasses them by 3 dB, enabling communication with an SNR of -11.5 dB or a maximum coupling loss of up to 170.5 dB.Comment: Wireless Communications and Networking Conference (WCNC), 201

Simulation-based cost-utility analysis of population screening-based alendronate use in Switzerland

Summary: A simulation model adopting a health system perspective showed population-based screening with DXA, followed by alendronate treatment of persons with osteoporosis, or with anamnestic fracture and osteopenia, to be cost-effective in Swiss postmenopausal women from age 70, but not in men. Introduction: We assessed the cost-effectiveness of a population-based screen-and-treat strategy for osteoporosis (DXA followed by alendronate treatment if osteoporotic, or osteopenic in the presence of fracture), compared to no intervention, from the perspective of the Swiss health care system. Methods: A published Markov model assessed by first-order Monte Carlo simulation was refined to reflect the diagnostic process and treatment effects. Women and men entered the model at age 50. Main screening ages were 65, 75, and 85years. Age at bone densitometry was flexible for persons fracturing before the main screening age. Realistic assumptions were made with respect to persistence with intended 5years of alendronate treatment. The main outcome was cost per quality-adjusted life year (QALY) gained. Results: In women, costs per QALY were Swiss francs (CHF) 71,000, CHF 35,000, and CHF 28,000 for the main screening ages of 65, 75, and 85years. The threshold of CHF 50,000 per QALY was reached between main screening ages 65 and 75years. Population-based screening was not cost-effective in men. Conclusion: Population-based DXA screening, followed by alendronate treatment in the presence of osteoporosis, or of fracture and osteopenia, is a cost-effective option in Swiss postmenopausal women after age 7

Dynamical Mass Ejection from Binary Neutron Star Mergers

We present fully general-relativistic simulations of binary neutron star mergers with a temperature and composition dependent nuclear equation of state. We study the dynamical mass ejection from both quasi-circular and dynamical-capture eccentric mergers. We systematically vary the level of our treatment of the microphysics to isolate the effects of neutrino cooling and heating and we compute the nucleosynthetic yields of the ejecta. We find that eccentric binaries can eject significantly more material than quasi-circular binaries and generate bright infrared and radio emission. In all our simulations the outflow is composed of a combination of tidally- and shock-driven ejecta, mostly distributed over a broad $\sim 60^\circ$ angle from the orbital plane, and, to a lesser extent, by thermally driven winds at high latitudes. Ejecta from eccentric mergers are typically more neutron rich than those of quasi-circular mergers. We find neutrino cooling and heating to affect, quantitatively and qualitatively, composition, morphology, and total mass of the outflows. This is also reflected in the infrared and radio signatures of the binary. The final nucleosynthetic yields of the ejecta are robust and insensitive to input physics or merger type in the regions of the second and third r-process peaks. The yields for elements on the first peak vary between our simulations, but none of our models is able to explain the Solar abundances of first-peak elements without invoking additional first-peak contributions from either neutrino and viscously-driven winds operating on longer timescales after the mergers, or from core-collapse supernovae.Comment: 19 pages, 10 figures. We corrected a problem in the formulation of the neutrino heating scheme and re-ran all of the affected models. The main conclusions are unchanged. This version also contains one more figure and a number of improvements on the tex

Epidemiology and direct medical costs of osteoporotic fractures in men and women in Switzerland

The aim of this study was to estimate the hospitalization incidence and the total number of hospital days related to all fractures and osteoporotic fractures in the year 2000 in Switzerland and to compare these with data from other frequent disorders in men and women. The official administrative and medical statistics database of the Swiss Federal Office of Statistics (SFOS) from the year 2000 was used. It covered 81.2% of all registered patient admissions and was considered to be representative of the entire population. We included the ICD-10 codes of 84 diagnoses that were compatible with an underlying osteoporosis and applied the best matching age-specific osteoporosis attribution rates published for the ICD-9 diagnosis codes to the individual ICD-10 codes. To preserve comparability with previously published data from 1992, we grouped the data related to the ICD-10 fracture codes into seven diagnosis pools (fractures of the axial skeleton, fractures of the proximal upper limbs, fractures of the distal upper limbs, fractures of the proximal lower limbs, fractures of the distal lower limbs, multiple fractures, and osteoporosis) and analyzed them separately for women and men by age group. Incidences of hospitalization due to fractures were calculated, and the direct medical costs related to hospitalization were estimated. In addition, we compared the results with those from chronic pulmonary obstructive disease (COPD), stroke, acute myocardial infarction, heart failure, diabetes and breast carcinoma from the same database. In Switzerland during 2000, 62,535 hospitalizations for fractures (35,586 women and 26,949 men) were registered. Fifty-one percent of all fractures in women and 24% in men were considered as osteoporotic. The overall incidences of hospitalization due to fractures were 969 and 768 per 100,000 in women and men, respectively. The hospitalization incidences for fractures of the proximal lower limbs and the axial skeleton increased exponentially after the age of 65 years. The direct medical cost of hospitalization of patients with osteoporosis and/or related fractures was 357million CHF. Hip fractures accounted for approximately half of these costs in women and men. Among other common diseases in women and men, osteoporosis ranked number1 in women and number2 (behind COPD) in men. When compared with data from 1992, the average length of stay had shortened by 8.4 days for women and 4.7 days for men, leading to a decrease of almost 40% in direct medical costs related to acute hospitalizations. This apparent decrease in cost might result from a shift into the ambulatory cost segment, for which the assessment and management tools need to be developed. We conclude that, in 2000, osteoporosis continued to be a heavy burden on the Swiss healthcare system. Lack of awareness of the disease and its consequences prevents widespread use of drugs with anti-fracture efficacy. This limits their potential to reduce cost