bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Bright Reverse Shock Emission in the Optical Afterglows of Gamma-Ray Bursts in a Stratified Medium
Authors: Yi Shuang-Xi , Wu Xue-Feng , Zou Yuan-Chuan , Dai Zi-Gao 
Published: June 2020

Abstract
The reverse shock (RS) model is generally introduced to interpret the optical afterglows with the rapid rising and decaying, such as the early optical afterglow of GRB 990123 (which is also called the optical flash). In this paper, we collected 11 gamma-ray burst (GRB) early optical afterglows, which have signatures of dominant RS emission. Since the temporal slopes of the optical flashes are determined by both the medium density distribution index k and the electron spectral index p, we apply the RS model of the thin shell case to the optical flashes and determine the ambient medium of the progenitors. We find that the k value is in the range of 0–1.5. The k value in this paper is consistent with the result in Yi et al., where the forward shock model was applied to some onset bumps. However, the method adopted in this paper is only applicable to GRB afterglows with significant sharp rising and decaying RS emission. Our results indicate that the RS model can also be applied to confirm the circumburst medium, further implying that GRBs may have diverse circumburst media.
Quasar Microlensing Variability Studies Favor Shallow Accretion Disk Temperature Profiles
Authors: Cornachione Matthew A. , Morgan Christopher W. 
Published: June 2020

Abstract
We compare the microlensing-based continuum emission region size measurements in a sample of 15 gravitationally lensed quasars with estimates of luminosity-based thin disk sizes to constrain the temperature profile of the quasar continuum accretion region. If we adopt the standard thin disk model, we find a significant discrepancy between sizes estimated using the luminosity and those measured by microlensing of log(r

L
/r

μ
) = −0.57 ± 0.08 dex. If quasar continuum sources are simple, optically thick accretion disks with a generalized temperature profile

T
(
r
)
∝

r

−
β

, the discrepancy between the microlensing measurements and the luminosity-based size estimates can be resolved by a temperature profile slope 0.37 < β < 0.56 at 1σ confidence. This is shallower than the standard thin disk model (β = 0.75) at 3σ significance. We consider alternate accretion disk models that could produce such a temperature profile and reproduce the empirical continuum size scaling with black hole mass, including disk winds or disks with nonblackbody atmospheres.
Measuring Turbulent Motion in Planet-forming Disks with ALMA: A Detection around DM Tau and Nondetections around MWC 480 and V4046 Sgr
Authors: Flaherty Kevin , Hughes A. Meredith , Simon Jacob B. , Qi Chunhua , Bai Xue-Ning , Bulatek Alyssa , Andrews Sean M. , Wilner David J. , Kóspál Ágnes 
Published: June 2020

Abstract
Turbulence is a crucial factor in many models of planet formation, but it has only been directly constrained among a small number of planet-forming disks. Building on the upper limits on turbulence placed in disks around HD 163296 and TW Hya, we present ALMA CO J = 2–1 line observations at ∼0.″3 (20–50 au) resolution and 80 ms−1 channel spacing of the disks around DM Tau, MWC 480, and V4046 Sgr. Using parametric models of disk structure, we robustly detect nonthermal gas motions around DM Tau of between 0.25c

s
and 0.33c

s
, with the range dominated by systematic effects, making this one of the only systems with directly measured nonzero turbulence. Using the same methodology, we place stringent upper limits on the nonthermal gas motion around MWC 480 (<0.08c

s
) and V4046 Sgr (<0.12c

s
). The preponderance of upper limits in this small sample and the modest turbulence levels consistent with dust studies suggest that weak turbulence (α ≲ 10−3) may be a common, albeit not universal, feature of planet-forming disks. We explore the particular physical conditions around DM Tau that could lead this system to be more turbulent than the others.
Studies in Astronomical Time-series Analysis. VII. An Enquiry Concerning Nonlinearity, the rms–Mean Flux Relation, and Lognormal Flux Distributions
Authors: Scargle Jeffrey D. 
Published: June 2020

Abstract
A broad and widely used class of stationary, linear, additive time-series models can have statistical properties that many authors have asserted imply that the underlying process must be nonlinear, nonstationary, multiplicative, or inconsistent with shot noise. This result is demonstrated with exact and numerical evaluation of the model flux distribution function and dependence of flux standard deviation on mean flux (here and in the literature called the rms–flux relation). These models can (1) exhibit normal, lognormal, or other flux distributions; (2) show linear or slightly nonlinear rms–mean flux dependencies; and (3) match arbitrary second-order statistics of the time-series data. Accordingly, the above assertions cannot be made on the basis of statistical time-series analysis alone. Also discussed are ambiguities in the meaning of terms relevant to this study—linear, stationary, and multiplicative—and functions that can transform observed fluxes to a normal distribution as well as or better than the logarithm.
SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES). IV. Spatial Clustering and Halo Masses of Submillimeter Galaxies
Authors: Lim Chen-Fatt , Chen Chian-Chou , Smail Ian , Wang Wei-Hao , Tee Wei-Leong , Lin Yen-Ting , Scott Douglas , Toba Yoshiki , Chang Yu-Yen , Ao YiPing , Babul Arif , Bunker Andy , Chapman Scott C. , Clements David L. , Conselice Christopher J. , Gao Yu , Greve Thomas R. , Ho Luis C. , Hong Sungwook E. , Hwang Ho Seong , Koprowski Maciej , Michałowski Michał J. , Shim Hyunjin , Shu Xinwen , Simpson James M. 
Published: June 2020

Abstract
We analyze an extremely deep 450 μm image (1σ = 0.56 mJy beam−1) of a ≃300 arcmin2 area in the CANDELS/COSMOS field as part of the Sub-millimeter Common User Bolometric Array-2 Ultra Deep Imaging EAO Survey. We select a robust (signal-to-noise ratio ≥4) and flux-limited (≥4 mJy) sample of 164 submillimeter galaxies (SMGs) at 450 μm that have K-band counterparts in the COSMOS2015 catalog identified from radio or mid-infrared imaging. Utilizing this SMG sample and the 4705 K-band-selected non-SMGs that reside within the noise level ≤1 mJy beam−1 region of the 450 μm image as a training set, we develop a machine-learning classifier using K-band magnitude and color–color pairs based on the 13-band photometry available in this field. We apply the trained machine-learning classifier to the wider COSMOS field (1.6 deg2) using the same COSMOS2015 catalog and identify a sample of 6182 SMG candidates with similar colors. The number density, radio and/or mid-infrared detection rates, redshift and stellar-mass distributions, and the stacked 450 μm fluxes of these SMG candidates, from the S2COSMOS observations of the wide field, agree with the measurements made in the much smaller CANDELS field, supporting the effectiveness of the classifier. Using this SMG candidate sample, we measure the two-point autocorrelation functions from z = 3 down to z = 0.5. We find that the SMG candidates reside in halos with masses of ≃(2.0 ± 0.5) × 1013
h
−1
M
☉ across this redshift range. We do not find evidence of downsizing that has been suggested by other recent observational studies.
The Flare-dominated Accretion Mode of a Radio-bright Candidate Transitional Millisecond Pulsar
Authors: Li Kwan-Lok , Strader Jay , Miller-Jones James C. A. , Heinke Craig O. , Chomiuk Laura 
Published: June 2020

Abstract
We report new simultaneous X-ray and radio continuum observations of 3FGL J0427.9−6704, a candidate member of the enigmatic class of transitional millisecond pulsars. These XMM-Newton and Australia Telescope Compact Array observations of this nearly edge-on, eclipsing low-mass X-ray binary were taken in the sub-luminous disk state at an X-ray luminosity of

erg s−1. Unlike the few well-studied transitional millisecond pulsars, which spend most of their disk state in a characteristic high or low accretion mode with occasional flares, 3FGL J0427.9−6704 stayed in the flare mode for the entire X-ray observation of ∼20 hr, with the brightest flares reaching ∼2 × 1034 erg s−1. The source continuously exhibited flaring activity on timescales of ∼10–100 s in both the X-ray and optical/ultraviolet (UV). No measurable time delay between the X-ray and optical/UV flares is observed, but the optical/UV flares last longer, and the relative amplitudes of the X-ray and optical/UV flares show a large scatter. The X-ray spectrum can be well-fit with a partially absorbed power law (Γ ∼ 1.4–1.5), perhaps due to the edge-on viewing angle. Modestly variable radio continuum emission is present at all epochs, and is not eclipsed by the secondary, consistent with the presence of a steady radio outflow or jet. The simultaneous radio/X-ray luminosity ratio of 3FGL J0427.9−6704 is higher than any known transitional millisecond pulsars and comparable to that of stellar-mass black holes of the same X-ray luminosity, providing additional evidence that some neutron stars can be as radio-loud as black holes.
Gap-type Particle Acceleration in the Magnetospheres of Rotating Supermassive Black Holes
Authors: Katsoulakos Grigorios , Rieger Frank M. 
Published: June 2020

Abstract
The detection of rapidly variable gamma-ray emission in active galactic nuclei has generated renewed interest in magnetospheric particle acceleration and emission scenarios. In order to explore its potential, we study the possibility of steady gap acceleration around the null surface of a rotating black hole magnetosphere. We employ a simplified (1D) description along with the general relativistic expression of Gauss’s law, and we assume that the gap is embedded in the radiation field of a radiatively inefficient accretion flow. The model is used to derive expressions for the radial distribution of the parallel electric field component, the electron and positron charge density, the particle Lorentz factor, and the number density of γ-ray photons. We integrate the set of equations numerically, imposing suitable boundary conditions. The results show that the existence of a steady gap solution for a relative high value of the global current is in principle possible if charge injection of both species is allowed at the boundaries. We present gap solutions for different choices of the global current and the accretion rate. When put in context, our results suggest that the variable very-high-energy γ-ray emission in M87 could be compatible with a magnetospheric origin.
A Deep CFHT Optical Search for a Counterpart to the Possible Neutron Star–Black Hole Merger GW190814
Authors: Vieira Nicholas , Ruan John J. , Haggard Daryl , Drout Maria R. , Nynka Melania C. , Boyce Hope , Spekkens Kristine , Safi-Harb Samar , Carlberg Raymond G. , Fernández Rodrigo , Piro Anthony L. , Afsariardchi Niloufar , Moon Dae-Sik 
Published: June 2020

Abstract
We present a wide-field optical imaging search for electromagnetic counterparts to the likely neutron star–black hole (NS–BH) merger GW190814/S190814bv. This compact binary merger was detected through gravitational waves by the LIGO/Virgo interferometers, with masses suggestive of an NS–BH merger. We imaged the LIGO/Virgo localization region using the MegaCam instrument on the Canada–France–Hawaii Telescope (CFHT). We describe our hybrid observing strategy of both tiling and galaxy-targeted observations, as well as our image differencing and transient detection pipeline. Our observing campaign produced some of the deepest multiband images of the region between 1.7 and 8.7 days post-merger, reaching a 5σ depth of g > 22.8 (AB mag) at 1.7 days and i > 23.1 and i > 23.9 at 3.7 and 8.7 days, respectively. These observations cover a mean total integrated probability of 67.0% of the localization region. We find no compelling candidate transient counterparts to this merger in our images, which suggests that the lighter object was tidally disrupted inside of the BH’s innermost stable circular orbit, the transient lies outside of the observed sky footprint, or the lighter object is a low-mass BH. We use 5σ source detection upper limits from our images in the NS–BH interpretation of this merger to constrain the mass of the kilonova ejecta to be M
ej ≲ 0. 015M
⊙ for a “blue” (

) kilonova and M
ej ≲ 0. 04M
⊙ for a “red” (

) kilonova. Our observations emphasize the key role of large-aperture telescopes and wide-field imagers such as CFHT MegaCam in enabling deep searches for electromagnetic counterparts to gravitational-wave events.
Ecosystem services mapping and assessment for policy- and decision-making: Lessons learned from a comparative analysis of European case studies
Authors: Geneletti Davide , Adem Esmail Blal , Cortinovis Chiara , Arany Ildikó , Balzan Mario , van Beukering Pieter , Bicking Sabine , Borges Paulo , Borisova Bilyana , Broekx Steven , Burkhard Benjamin , Gil Artur , Inghe Ola , Kopperoinen Leena , Kruse Marion , Liekens Inge , Lowicki Damian , Mizgajski Andrzej , Mulder Sara , Nedkov Stoyan , Ostergard Hannah , Picanço Ana , Ruskule Anda , Santos-Martín Fernando , Sieber Ina M. , Svensson Johan , Vačkářů Dava , Veidemane Kristina 
Published: June 2020

This paper analyses and compares a set of case studies on ecosystem services (ES) mapping and assessment with the purpose of formulating lessons learned and recommendations. Fourteen case studies were selected during the EU Horizon 2020 “Coordination and Support Action” ESMERALDA to represent different policy- and decision-making processes throughout the European Union, across a wide range of themes, biomes and scales. The analysis is based on a framework that addresses the key steps of an ES mapping and assessment process, namely policy questions, stakeholder identification and involvement, application of mapping and assessment methods, dissemination and communication and implementation. The analysis revealed that most case studies were policy-orientated or gave explicit suggestions for policy implementation in different contexts, including urban, rural and natural areas. Amongst the findings, the importance of starting stakeholder engagement early in the process was confirmed in order to generate interest and confidence in the project and to increase their willingness to cooperate. Concerning mapping and assessment methods, it was found that the integration of methods and results is essential for providing a comprehensive overview from different perspectives (e.g. social, economic). Finally, lessons learned for effective implementation of ES mapping and assessment results are presented and discussed.
Graphical Abstarcat in Fig. 1.
Decisions Made By Critical Care Nurses During Mechanical Ventilation and Weaning in an Australian Intensive Care Unit
Authors: Rose Louise , Nelson Sioban , Johnston Linda , Presneill Jeffrey J. 
Published: June 2020

Background Responsibilities of critical care nurses for management of mechanical ventilation may differ among countries. Organizational interventions, including weaning protocols, may have a variable impact in settings that differ in nursing autonomy and interdisciplinary collaboration.
Objective To characterize the role of Australian critical care nurses in the management of mechanical ventilation.
Methods A 3-month, prospective cohort study was performed. All clinical decisions related to mechanical ventilation in a 24-bed, combined medical-surgical adult intensive care unit at the Royal Melbourne Hospital, a university-affiliated teaching hospital in Melbourne, Victoria, Australia, were determined.
Results Of 474 patients admitted during the 81-day study period, 319 (67%) received mechanical ventilation. Death occurred in 12.5% (40/319) of patients. Median durations of mechanical ventilation and intensive care stay were 0.9 and 1.9 days, respectively. A total of 3986 ventilation and weaning decisions (defined as any adjustment to ventilator settings, including mode change; rate or pressure support adjustment; and titration of tidal volume, positive end-expiratory pressure, or fraction of inspired oxygen) were made. Of these, 2538 decisions (64%) were made by nurses alone, 693 (17%) by medical staff, and 755 (19%) by nurses and staff in collaboration. Decisions made exclusively by nurses were less common for patients with predominantly respiratory disease or multiple organ dysfunction than for other patients.
Conclusions In this unit, critical care nurses have high levels of responsibility for, and autonomy in, the management of mechanical ventilation and weaning. Revalidation of protocols for ventilation practices in other clinical contexts may be needed.
Skin Integrity in Critically Ill and Injured Children
Authors: Schindler Christine A. , Mikhailov Theresa A. , Fischer Kay , Lukasiewicz Gloria , Kuhn Evelyn M. , Duncan Linda 
Published: June 2020

Background Skin breakdown increases the cost of care, may lead to increased morbidity, and has negative psychosocial implications because of secondary scarring or alopecia. The scope of this problem has not been widely studied in critically ill and injured children.
Objectives To determine the incidence of skin breakdown in critically ill and injured children and to compare the characteristics of patients who experience skin breakdown with those of patients who do not.
Methods Admission and follow-up data for a 15-week period were collected retrospectively on children admitted to a large pediatric intensive care unit. The incidence of skin breakdown was calculated. The risk for skin breakdown associated with potential risk factors (relative risk) and 95% confidence intervals were determined.
Results The sample consisted of 401 distinct stays in the intensive care unit for 373 patients. During the 401 stays, skin breakdown occurred in 34 (8.5%), redness in 25 (6.2%), and breakdown and redness in 13 (3.2%); the overall incidence was 18%. Patients who had skin breakdown or redness were younger, had longer stays, and were more likely to have respiratory illnesses and require mechanical ventilatory support than those who did not. Patients who had skin breakdown or redness had a higher risk of mortality than those who did not.
Conclusions Risk factors for skin breakdown were similar to those previously reported. Compared with children of other ages, children 2 years or younger are at higher risk for skin breakdown.
Evaluation of Delivery of Enteral Nutrition in Critically Ill Patients Receiving Mechanical Ventilation
Authors: O’Meara Debra , Mireles-Cabodevila Eduardo , Frame Fran , Hummell A. Christine , Hammel Jeffrey , Dweik Raed A. , Arroliga Alejandro C. 
Published: June 2020

Background Published reports consistently describe incomplete delivery of prescribed enteral nutrition. Which specific step in the process delays or interferes with the administration of a full dose of nutrients is unclear.Objectives To assess factors associated with interruptions in enteral nutrition in critically ill patients receiving mechanical ventilation.Methods An observational prospective study of 59 consecutive patients who required mechanical ventilation and were receiving enteral nutrition was done in an 18-bed medical intensive care unit of an academic center. Data were collected prospectively on standardized forms. Steps involved in the feeding process from admission to discharge were recorded, each step was timed, and delivery of nutrition was quantified.Results Patients received approximately 50% (mean, 1106.3; SD, 885.9 Cal) of the prescribed caloric needs. Enteral nutrition was interrupted 27.3% of the available time. A mean of 1.13 interruptions occurred per patient per day; enteral nutrition was interrupted a mean of 6 (SD, 0.9) hours per patient each day. Prolonged interruptions were mainly associated with problems related to small-bore feeding tubes (25.5%), increased residual volumes (13.3%), weaning (11.7%), and other reasons (22.8%). Placement and confirmation of placement of the small-bore feeding tube were significant causes of incomplete delivery of nutrients on the day of admission.Conclusions Delivery of enteral nutrition in critically ill patients receiving mechanical ventilation is interrupted by practices embedded in the care of these patients. Evaluation of the process reveals areas to improve the delivery of enteral nutrition.
Petrol ve Doğalgazın Uluslararası Piyasalara Ulaştırılmasında Jeopolitik Konum ve Kimliğin Etkilerinin İncelenmesi: Azerbaycan-Türkiye İlişkileri Örneği
Authors: Salih Emir Mutluer  
Published: June 2020

Jeopolitik, bir devletin yer aldığı ülkeler coğrafyasındaki stratejik önemini vurgulayan önemli bir kavramdır. Ülkelerin coğrafi/fiziki özellikleri (iklim, bitki örtüsü, yeryüzü şekilleri, yer altı ve yer üstü zenginlikleri vb.), komşuları ve ilişki düzeyi, tarihi/kültürel dokusu (geleneksel yapısı, medeniyete ait bilgileri, dil yapısı, değer yapıları vb.), dinsel ve etnik özellikleri (inanç, millet, köken vb), iktisadi yapısı (üretim ve tüketim kapasitesi vb), ulaşım imkânları (deniz, liman, karayolu, havayolu gibi), uluslararası platformlardaki rolü ve askeri gücü gibi daha pek çok özellik jeopolitik önemi belirleyen etmenler arasında sayılabilir. Türkiye, bulunduğu coğrafya bakımından iki kıta arasında köprü konumunda yer alması, uluslararası sulara açılan önemli liman ve boğazlara sahip olması Türkiye’yi jeopolitik anlamda bulunduğu bölgede önemli bir merkez haline getirmektedir. Ayrıca, Türkiye’nin petrol ülkelerine olan coğrafi yakınlığı, İstanbul ve Çanakkale gibi iki önemli boğaza sahip olması ve ülkede bulunan önemli limanları sayesinde sahip olduğu milli ve dini kimliğinin de etkisiyle Hazar Havzası’nda bulunan petroller güvenli bir şekilde uluslararası pazarlara aktarılabilmektedir. Jeopolitiğin bir ülkenin dış siyaseti üzerinde tek başına belirleyici bir faktör mü? Yoksa, jeopolitiğin yanında milli kimlik, kültür gibi faktörlerinde dış siyasette etkisi var mıdır? Sorularına ışık tutmak amacıyla oluşturulmuş bir çalışmadır.
Tuz Stresi Altındaki Biber Bitkisindeki Kalsiyum Uygulamalarının Antioksidatif Enzim Aktivitelerine Etkisinin Araştırılması
Authors: Fikret YAŞAR  , Ömihan YILDIRIM  , Özlem ÜZAL  
Published: June 2020

Demre sivri biber çeşidinin kullanıldığı çalışmada, tuz stresi altındaki biber bitkisine farklı dozlarda uygulanan kalsiyumun (Ca) bitki gelişimi ve antioksidant enzim aktiviteleri üzerine etkileri araştırılmıştır. Çalışma kontrollü şartlardaki 16/8 saatlik aydınlık/ karanlık fotoperiyotta, 25 oC de ve %70 nemli iklim odasında yürütülmüştür. Çalışmada toplam bitki ağırlığı ile bitkilerin tuza dayanım skalaları belirlenmiştir. Stres altındaki bitkilerde meydana gelen biyokimyasal değişiklikleri belirlemek amacıyla bitki yapraklarındaki antioksidant enzim aktiviteleri (Katalaz (CAT), Askorbat peroksidaz (APX), Süperoksit dismutaz (SOD)) belirlenmiştir. Tuz stresi altındaki bitkilere uygulanan kalsiyumun dozu arttıkça bitkilerin toplam ağırlıklarında artış olmuştur. Bu sonuçlara paralel olarak, bitkiler strese girmedikleri için ya da çok az stres oluştuğu için her üç enzim aktivitesinde Ca doz artışına bağlı olarak düşüşler olmuştur. Tuz stresi altındaki biber fidelerine artan dozlarda Ca uygulamalarının tuzun olumsuz etkisini azaltmada kısmen de olsa etkili olduğu yapılan ölçüm ve analizler sonucunda söylenebilir.