Low-mass Pop III star formation due to the HD-cooling induced by weak Lyman-Werner radiation

Lyman-Werner (LW) radiation photodissociating molecular hydrogen (H$_2$) influences the thermal and dynamical evolution of the Population III (Pop III) star-forming gas cloud. The effect of powerful LW radiation has been well investigated in the context of supermassive black hole formation in the early universe. However, the average intensity in the early universe is several orders of magnitude lower. For a comprehensive study, we investigate the effects of LW radiation at $18$ different intensities, ranging from $J_{\rm LW}/J_{21}=0$ (no radiation) to $30$ (H-cooling cloud), on the primordial star-forming gas cloud obtained from a three-dimensional cosmological simulation. The overall trend with increasing radiation intensity is a gradual increase in the gas cloud temperature, consistent with previous works. Due to the HD-cooling, on the other hand, the dependence of gas cloud temperature on $J_{\rm LW}$ deviates from the aforementioned increasing trend for a specific range of intensities ($J_{\rm LW}/J_{21}=0.025-0.09$). In HD-cooling clouds, the temperature remained below $200$ K during $10^5$ yr after the first formation of the high-density region, maintaining a low accretion rate. Finally, the HD-cooling clouds have only a low-mass dense core (above $10^8\,{\rm cm^{-3}}$) with about $1-16\, M_{\odot}$, inside which a low-mass Pop III star with $\leq\!0.8\,M_{\odot}$ (so-called "surviving star") could form. The upper limit of star formation efficiency $M_{\rm core}/M_{\rm vir, gas}$ significantly decreases from $10^{-3}$ to $10^{-5}$ as HD-cooling becomes effective. This tendency indicates that, whereas the total gas mass in the host halo increases with the LW radiation intensity, the total Pop III stellar mass does not increase similarly.Comment: 13 pages, 8 figures, submitted to Ap

Formation of first star clusters under the supersonic gas flow -- I. Morphology of the massive metal-free gas cloud

We performed $42$ simulations of the first star formation with initial supersonic gas flows relative to the dark matter at the cosmic recombination era. Increasing the initial streaming velocities led to delayed halo formation and increased halo mass, enhancing the mass of the gravitationally shrinking gas cloud. For more massive gas clouds, the rate of temperature drop during contraction, in other words, the structure asymmetry, becomes more significant. When the maximum and minimum gas temperature ratios before and after contraction exceed about ten, the asymmetric structure of the gas cloud prevails, inducing fragmentation into multiple dense gas clouds. We continued our simulations until $10^5$ years after the first dense core formation to examine the final fate of the massive star-forming gas cloud. Among the $42$ models studied, we find the simultaneous formation of up to four dense gas clouds, with a total mass of about $2254\,M_\odot$. While the gas mass in the host halo increases with increasing the initial streaming velocity, the mass of the dense cores does not change significantly. The star formation efficiency decreases by more than one order of magnitude from $\epsilon_{\rm III} \sim 10^{-2}$ to $10^{-4}$ when the initial streaming velocity, normalised by the root mean square value, increases from 0 to 3.Comment: 15 pages, 16 figures, 1 table, Accepted for publication in MNRA

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Low-mass Population III Star Formation due to the HD Cooling Induced by Weak Lyman–Werner Radiation

Lyman–Werner (LW) radiation photodissociating molecular hydrogen (H _2 ) influences the thermal and dynamical evolution of the Population III (Pop III) star-forming gas cloud. The effect of powerful LW radiation has been well investigated in the context of supermassive black hole formation in the early Universe. However, the average intensity in the early Universe is several orders of magnitude lower. For a comprehensive study, we investigate the effects of LW radiation at 18 different intensities, ranging from J _LW / J _21 = 0 (no radiation) to 30 (H-cooling cloud), on the primordial star-forming gas cloud obtained from a three-dimensional cosmological simulation. The overall trend with increasing radiation intensity is a gradual increase in the gas cloud temperature, consistent with previous works. Due to the HD cooling, however, the dependence of gas cloud temperature on J _LW deviates from the aforementioned increasing trend for a specific range of intensities ( J _LW / J _21 = 0.025–0.09). In HD-cooling clouds, the temperature remained below 200 K during 10 ^5 yr after the first formation of the high-density region, maintaining a low accretion rate. Finally, the HD-cooling clouds have only a low-mass dense core (above 10 ^8 cm ^−3 ) with about 1–16 M _⊙ , inside of which a low-mass Pop III star with ≤0.8 M _⊙ (a so-called “surviving star”) could form. The upper limit of star formation efficiency ${M}_{\mathrm{core}}/{M}_{\mathrm{vir},\mathrm{gas}}$ significantly decreases from 10 ^−3 to 10 ^−5 as HD cooling becomes effective. This tendency indicates that, whereas the total gas mass in the host halo increases with the LW radiation intensity, the total Pop III stellar mass does not increase similarly

Use of machine learning for a helium line intensity ratio method in Magnum-PSI

Optical emission spectroscopy (OES) of helium (He) line intensities has been used to measure the electron density, n e, and temperature, T e, in various plasma devices. In this study, a neural network with five hidden layers is introduced to model the relation between the OES data and n e/T e from laser Thomson scattering in the linear plasma device Magnum-PSI and compared to multiple regression analysis. It is shown that the neural network reduces the residual errors of prediction values (n e and T e) less than half those of the multiple regression analysis in the ranges of 2 × 10 18&lt;n e&lt;8×10 20m−3 and 0.1&lt;T e&lt;4 eV. We checked two different data splitting methods for training and validation data, i.e., with and without considering the unit of discharge. A comparison of the splitting methods suggests that the residual error will decrease to ∼10% even for a new discharge data when accumulating a sufficient data set.</p

Use of machine learning for a helium line intensity ratio method in Magnum-PSI

Optical emission spectroscopy (OES) of helium (He) line intensities has been used to measure the electron density, n e, and temperature, T e, in various plasma devices. In this study, a neural network with five hidden layers is introduced to model the relation between the OES data and n e/T e from laser Thomson scattering in the linear plasma device Magnum-PSI and compared to multiple regression analysis. It is shown that the neural network reduces the residual errors of prediction values (n e and T e) less than half those of the multiple regression analysis in the ranges of 2 × 10 18&amp;lt;n e&amp;lt;8×10 20m−3 and 0.1&amp;lt;T e&amp;lt;4 eV. We checked two different data splitting methods for training and validation data, i.e., with and without considering the unit of discharge. A comparison of the splitting methods suggests that the residual error will decrease to ∼10% even for a new discharge data when accumulating a sufficient data set

Interstitial lung disease with prolonged fever that occurred during long-term administration of olaparib in a 74-year-old ovarian cancer patient: Radiological features and considerations for preventing delayed diagnosis

A 74-year-old woman, who had been receiving olaparib for the treatment of ovarian cancer for more than a year, visited the emergency department complaining of a fever that had lasted for 1 month. She had been taking antipyretics and antibiotics for her fever, but without any effect. Although she had no symptoms other than fever, she had stopped taking olaparib for 1 week before her visit because she had developed anemia caused by myelosuppression from olaparib. After discontinuing olaparib, her maximum body temperature decreased. On admission, chest X-ray revealed no abnormalities, but chest CT showed diffuse ground-glass opacities. Chest CT taken 5 days later showed partial improvement; therefore, we diagnosed her with interstitial lung disease (ILD) associated with olaparib. After short-term steroid treatment, the ground-glass opacities disappeared, and the patient became afebrile. The CT scan taken for tumor evaluation 2 days before the onset of fever showed a few centrilobular nodular opacities and small patchy ground-glass opacities. These findings could indicate early lesions of ILD, but they seemed inconspicuous and nonspecific, and it might have been difficult to diagnose ILD then. To date, few cases of ILD associated with olaparib have been reported. However, based on previous reports, fever is often seen, and CT findings mainly comprise diffuse ground-glass opacities, and in some cases, centrilobular nodular shadows. Thus, in conjunction with the findings of the present case, these characteristics may be representative of olaparib-induced ILD