bluuebunny/crossref_metadata_2025_split huggingface dataset:
1ES 1927+654: An AGN Caught Changing Look on a Timescale of Months
Authors: Trakhtenbrot Benny , Arcavi Iair , MacLeod Chelsea L. , Ricci Claudio , Kara Erin , Graham Melissa L. , Stern Daniel , Harrison Fiona A. , Burke Jamison , Hiramatsu Daichi , Hosseinzadeh Griffin , Howell D. Andrew , Smartt Stephen J. , Rest Armin , Prieto Jose L. , Shappee Benjamin J. , Holoien Thomas W.-S. , Bersier David , Filippenko Alexei V. , Brink Thomas G. , Zheng WeiKang , Li Ruancun , Remillard Ronald A. , Loewenstein Michael 
Published: September 2019

Abstract
We study the sudden optical and ultraviolet (UV) brightening of 1ES 1927+654, which until now was known as a narrow-line active galactic nucleus (AGN). 1ES 1927+654 was part of the small and peculiar class of “true Type-2” AGNs that lack broad emission lines and line-of-sight obscuration. Our high-cadence spectroscopic monitoring captures the appearance of a blue, featureless continuum, followed several weeks later by the appearance of broad Balmer emission lines. This timescale is generally consistent with the expected light travel time between the central engine and the broadline emission region in (persistent) broadline AGN. Hubble Space Telescope spectroscopy reveals no evidence for broad UV emission lines (e.g., C iv
λ1549, C iii] λ1909, Mg ii
λ2798), probably owing to dust in the broadline emission region. To the best of our knowledge, this is the first case where the lag between the change in continuum and in broadline emission of a “changing look” AGN has been temporally resolved. The nature and timescales of the photometric and spectral evolution disfavor both a change in line-of-sight obscuration and a change of the overall rate of gas inflow as driving the drastic spectral transformations seen in this AGN. Although the peak luminosity and timescales are consistent with those of tidal disruption events seen in inactive galaxies, the spectral properties are not. The X-ray emission displays a markedly different behavior, with frequent flares on timescales of hours to days, and will be presented in a companion publication.
A Radio-to-millimeter Census of Star-forming Galaxies in Protocluster 4C 23.56 at z = 2.5: Global and Local Gas Kinematics
Authors: Lee Minju M. , Tanaka Ichi , Kawabe Ryohei , Aretxaga Itziar , Hatsukade Bunyo , Izumi Takuma , Kajisawa Masaru , Kodama Tadayuki , Kohno Kotaro , Nakanishi Kouichiro , Saito Toshiki , Tadaki Ken-ichi , Tamura Yoichi , Umehata Hideki , Zeballos Milagros 
Published: September 2019

Abstract
We present a study of the gas kinematics of star-forming galaxies associated with protocluster 4C 23.56 at z = 2.49 using 0.″4 resolution CO (4–3) data taken with ALMA. Eleven Hα emitters (HAEs) are detected in CO (4–3), including six HAEs that were previously detected in CO (3–2) at a coarser angular resolution. The detections in both CO lines are broadly consistent in the line widths and the redshifts, confirming both detections. With an increase in the number of spectroscopic redshifts, we confirm that the protocluster is composed of two merging groups with a total halo mass of log (M
cl/M
⊙) = 13.4–13.6, suggesting that the protocluster would evolve into a Virgo-like cluster (>1014
M
⊙). We compare the CO line widths and the CO luminosities with other (proto)clusters (n
gal = 91) and general field (n
gal = 80) galaxies from other studies. The 4C 23.56 protocluster galaxies have CO line widths and luminosities comparable to other protocluster galaxies on average. On the other hand, the CO line widths are on average broader by ≈50% compared to field galaxies, while the median CO luminosities are similar. The broader line widths can be attributed to both effects of unresolved gas-rich mergers and/or compact gas distribution, which is supported by our limited but decent angular resolution observations and the size estimate of three galaxies. Based on these results, we argue that gas-rich mergers may play a role in the retention of the specific angular momentum to a value similar to that of field populations during cluster assembly, though we need to verify this with a larger number of samples.
Exploring the Mass Segregation Effect of X-Ray Sources in Globular Clusters. II. The Case of Terzan 5
Authors: Cheng Zhongqun , Li Zhiyuan , Fang Taotao , Li Xiangdong , Xu Xiaojie 
Published: September 2019

Abstract
Using archival Chandra observations with a total effective exposure of 734 ks, we derive an updated catalog of point sources in the massive globular cluster (GC) Terzan 5. Our catalog covers an area of 58.1 arcmin2 (R ≤ 4.′3) with 489 X-ray sources, and more than 75% of these sources are first detected in this cluster. We find significant dips in the radial distribution profiles of X-ray sources in Terzan 5, with the projected distance and width of the distribution dips for bright (L
X ≳ 9.5 × 1030 erg s−1) X-ray sources larger than those of the faint (L
X ≲ 9.5 × 1030 erg s−1) sources. By fitting the radial distribution of the X-ray sources with a “generalized King model,” we estimated an average mass of 1.48 ± 0.11 and 1.27 ± 0.13 M
⊙ for the bright and faint X-ray sources, respectively. These results are in agreement with that observed in 47 Tuc, which may suggest a universal mass segregation effect for X-ray sources in GCs. Compared with 47 Tuc, we show that the two-body relaxation timescale of Terzan 5 is much smaller, but its dynamical age is significantly younger than 47 Tuc. These features suggest that the evolution of Terzan 5 is not purely driven by two-body relaxation, and the tidal stripping effect also plays an important role in accelerating the dynamical evolution of this cluster.
Awareness of Hygiene and Safety Practices on Raw Milk Produced and Consumed in Kiambu County, Kenya
Authors: Njoroge Stephen K. , Njue Lucy G. 
Published: September 2019

Background: In Kenya Food safety has been a subject of concern in the recent past due to an increase in chronic illnesses. This was triggered by challenges in quality control, unregulated trade of milk by hawkers, and a minimal level of safety awareness among the farmers.
Objective: The study was aimed at finding out awareness of safety practices on raw milk produced and consumed in Kiambu County.
Methods: A cross-section study was carried out, to examine hygiene standards and safety aspects among dairy farmers at Gatundu South Constituency, mainly in three regions namely Kiganjo, Gatei and Gatundu town. Purposive sampling technique was used to select 33 participants in each locality.
Results: The study showed small scale farmers accounted for (98%) who keep 2 to 3 cows. The quality assurance of the products accounted for more than (97%) hence not significant (p>0.05). The record management at the farm level had less than 40% of farmers, hence no significance difference (p>0.05). The milk rejection accounted for 97%, and there was a significant ((p˂0.05)). In contamination with antibiotics and preservatives. Brokers who vend milk in the sub-urban centers in Thika town, Ruiru town, and Nairobi accounted for (14%)... The use of health records was not a priority among the farmers, coupled with irregular withdrawal periods; ranging from 48 hours to 72 hours.
Conclusion: Hygiene standards and safety aspects among dairy farmers in Kiambu County are compromised. Subsequently, there is a need to enforce controls in; informal marketing channels, besides training, infrastructural development, code of practice and inspections to enhance the quality and safety of dairy products along the supply chain.
A longitudinal study of factors predicting students’ intentions to leave upper secondary school in Norway
Authors: Haugan Jan Arvid , Frostad Per , Mjaavatn Per-Egil 
Published: September 2019

AbstractThis article illuminates factors predicting students’ intention to leave upper secondary school. The research is anchored in an ecological theoretical perspective that considers dropout as a multifaceted phenomenon that culminates in the decision to leave school. Based on this, we have used a longitudinal research design to investigate to what extent factors related to students’ experiences predict their intention to leave school early. The sample in this study comprises 1695 students from upper secondary schools in the county of Trøndelag in Norway. We ran descriptive analyses, correlations and hierarchical regression to analyse our data. In the stepwise causal modelling, the independent variables were placed in the same order as the hypotheses were formulated. This enabled us to test each of the independent variables to explain how much variance there was in the dependent variable (intention to leave) beyond those entered in the previous steps. The results show that the students’ grades from elementary school, parental and teacher support and school engagement in upper secondary school are important explanatory factors leading to dropout. Loneliness at secondary school and students’ ability to cope with stressful life events seem to be the two most important predictive factors in relation to the students’ thoughts about leaving.
Ultrasound Image Based Human Gallbladder 3D Modelling along with Volume and Stress Level Assessment
Authors: Li Wen-Guang 
Published: September 2019

AbstractPurposeThree-dimensional (3D) gallbladder (GB) geometrical models are essential to GB motor function evaluation and GB wall biomechanical property identification by employing finite element analysis (FEA) in GB disease diagnosis with ultrasound systems. Methods for establishing such 3D geometrical models based on static two-dimensional (2D) ultrasound images scanned along the long-axis/sagittal and short-axis/transverse cross-sections in routine GB disease diagnosis at the beginning of emptying phase have not been documented in the literature so far.MethodsBased on two custom MATLAB codes composed, two images were segmented manually to secure two sets of the scattered points for the long- and short-axis GB cross-section edges; and the points were best fitted with a piecewise cubic spline function, and the short-axis cross-section edges were lofted along the long-axis to yield a 3D geometrical model, then GB volume of the model was figured out. The model was read into SolidWorks for real surface generation and involved in ABAQUS for FEA.Results3D geometrical models of seven typical GB samples were established. Their GB volumes are with 15.5% and − 4.4% mean errors in comparison with those estimated with the ellipsoid model and sum-of-cylinders method but can be correlated to the latter very well. The maximum first principal in-plane stress in the 3D models is higher than in the ellipsoid model by a factor of 1.76.ConclusionsA numerical method was put forward here to create 3D GB geometrical models and can be applied to GB disease diagnosis and GB shape analysis with principal component method potentially in the future.
The Challenge with Clinical Radiology Electives: Student and Faculty Perspectives Identify Areas for Improvement
Authors: Darras Kathryn E. , Spouge Rebecca , Kang Heejun , Scurfield Kathryn J. , Harper Leonie , Yee Adrian , Chang Silvia D. , Forster Bruce B. , Nicolaou Savvas 
Published: September 2019

Purpose To determine medical students' and radiologists’ attitude toward radiology electives at a distributed medical school and identify specific areas for improvement. Methods During a single academic year, both students and faculty preceptors were surveyed anonymously following a senior radiology elective. The survey was based on an established theoretical framework for studying the educational environment which takes into account domains: (1) goal orientation, (2) organization/regulation, and (3) relationships. Mann-Whitney tests were performed to determine if there was any difference between the overall satisfaction of students and preceptors, responses from the different elective sites and students’ ratings of the domains. Statistical significance was set at P < .05. Thematic analysis was performed on the narrative comments to identify specific challenges. Results The response rate was 82.0% for students (95/116) and 19.5% (31/159) for radiologists. There was no difference in responses based on elective site. Overall, the elective was viewed positively by both groups however students rated their experience as significantly better than their preceptors ( P = .0012). Students viewed the relationships domain more positively than both the other two (goal orientation, P = .0001; organization/regulation, P = .0038). Thematic analysis identified that the student challenges were lack of autonomy, structured teaching, and preceptor continuity and the preceptor challenges were ambiguous learning objectives/expectations and insufficient resources. Conclusions The radiology elective challenges identified in this study provide educators with specific areas to target when updating radiology electives. A better elective experience may improve students' radiology knowledge and attitude towards the specialty as well as radiologists’ interest in teaching.
Do adjuvants reduce the antagonism of quizalofop-p-ethyl when mixed with bispyribac-Na?
Authors: Webster L. Connor , Webster Eric P. , Blouin David C. , McKnight Benjamin M. 
Published: September 2019

AbstractAcetyl co-enzyme A carboxylase (ACCase)-resistant rice allows quizlaofop-p-ethyl to be applied as a POST control of troublesome grass weeds. A field study was conducted in 2017 and 2018 at the H. Rouse Caffey Rice Research Station near Crowley, LA, to evaluate the influence of a crop oil concentrate (COC), a silicon-based surfactant plus a nitrogen source (SNS), or a high-concentrate COC (HCOC) in overcoming the grass weed control antagonism of quizalofop-p-ethyl when mixed with bispyribac-Na. Quizalofop-p-ethyl was applied at 120 g ai ha−1, bispyribac-Na was applied at 34 g ai ha−1, and all adjuvants were applied at 1% vol/vol. Antagonistic interactions were observed at 14 d after treatment (DAT) when quizalofop-p-ethyl was mixed with bispyribac-Na with no adjuvant for control of barnyardgrass, the non–ACCase-tolerant rice cultivars ‘CL-111’ and ‘CLXL-745’, and red rice. At 14 DAT, antagonism of quizalofop-p-ethyl for control of barnyardgrass was observed when mixed with bispyribac-Na plus COC, SNS, or HCOC, with an observed control of 43%, 63%, and 86%, respectively, compared with an expected control of 95% for quizalofop-p-ethyl alone. However, the antagonism of quizalofop-p-ethyl when mixed with bispyribac-Na plus HCOC for barnyardgrass control at 14 DAT was overcome by 28 DAT, with an observed control of 91%, compared with an expected control of 97%. Synergistic or neutral interactions were observed at 14 and 28 DAT when COC, SNS, or HCOC was added to a mixture of quizalofop-p-ethyl plus bispyribac-Na for CL-111, CLXL-745, and red rice control. According to the results of this study, HCOC is the most effective adjuvant for quizalofop-p-ethyl and bispyribac-Na mixtures for control of weedy rice and barnyardgrass.
Non-canonical transcriptional regulation of heme oxygenase in Aedes aegypti
Authors: Bottino-Rojas Vanessa , Pereira Luiza O. R. , Silva Gabriela , Talyuli Octavio A. C. , Dunkov Boris C. , Oliveira Pedro L. , Paiva-Silva Gabriela O. 
Published: September 2019

AbstractHeme oxygenase (HO) is a ubiquitous enzyme responsible for heme breakdown, which yields carbon monoxide (CO), biliverdin (BV) and ferrous ion. Here we show that the Aedes aegypti heme oxygenase gene (AeHO – AAEL008136) is expressed in different developmental stages and tissues. AeHO expression increases after a blood meal in the midgut, and its maximal transcription levels overlaps with the maximal rate of the further modified A. aegypti biglutaminyl-biliverdin (AeBV) pigment production. HO is a classical component of stress response in eukaryotic cells, being activated under oxidative stress or increased heme levels. Indeed, the final product of HO activity in the mosquito midgut, AeBV, exerts a protective antioxidant activity. AeHO, however, does not seem to be under a classical redox-sensitive transcriptional regulation, being unresponsive to heme itself, and even down regulated when insects face a pro-oxidant insult. In contrast, AeHO gene expression responds to nutrient sensing mechanisms, through the target of rapamycin (TOR) pathway. This unusual transcriptional control of AeHO, together with the antioxidant properties of AeBV, suggests that heme degradation by HO, in addition to its important role in protection of Aedes aegypti against heme exposure, also acts as a digestive feature, being an essential adaptation to blood feeding.
Prognostic Modeling and Prevention of Diabetes Using Machine Learning Technique
Authors: Perveen Sajida , Shahbaz Muhammad , Keshavjee Karim , Guergachi Aziz 
Published: September 2019

AbstractStratifying individuals at risk for developing diabetes could enable targeted delivery of interventional programs to those at highest risk, while avoiding the effort and costs of prevention and treatment in those at low risk. The objective of this study was to explore the potential role of a Hidden Markov Model (HMM), a machine learning technique, in validating the performance of the Framingham Diabetes Risk Scoring Model (FDRSM), a well-respected prognostic model. Can HMM predict 8-year risk of developing diabetes in an individual effectively? To our knowledge, no study has attempted use of HMM to validate the performance of FDRSM. We used Electronic Medical Record (EMR) data, of 172,168 primary care patients to derive the 8-year risk of developing diabetes in an individual using HMM. The Area Under Receiver Operating Characteristic Curve (AROC) in our study sample of 911 individuals for whom all risk factors and follow up data were available is 86.9% compared to AROCs of 78.6% and 85% reported in a previously conducted validation study of FDRSM in the same Canadian population and the Framingham study respectively. These results demonstrate that the discrimination capability of our proposed HMM is superior to the validation study conducted using the FDRSM in a Canadian population and in the Framingham population. We conclude that HMM is capable of identifying patients at increased risk of developing diabetes within the next 8-years.
Integrative models explain the relationships between species richness and productivity in plant communities
Authors: Wang Zhenhong , Chiarucci Alessandro , Arratia Juan F. 
Published: September 2019

AbstractThe relationship between plant productivity and species richness is one of the most debated and important issues in ecology. Ecologists have found numerous forms of this relationship and its underlying processes. However, theories and proposed drivers have been insufficient to completely explain the observed variation in the forms of this relationship. Here, we developed and validated integration models capable of combining twenty positive or negative processes affecting the relationship. The integration models generated the classic humped, asymptotic, positive, negative and irregular forms and other intermediate forms of the relationship between plant richness and productivity. These forms were linked to one another and varied according to which was considered the dependent variable. The total strengths of the different positive and negative processes are the determinants of the forms of the relationship. Positive processes, such as resource availability and species pool effects, can offset the negative effects of disturbance and competition and change the relationship. This combination method clarifies the reasons for the diverse forms of the relationship and deepens our understanding of the interactions among processes.
Slow and fast single photons from a quantum dot interacting with the excited state hyperfine structure of the Cesium D1-line
Authors: Kroh Tim , Wolters Janik , Ahlrichs Andreas , Schell Andreas W. , Thoma Alexander , Reitzenstein Stephan , Wildmann Johannes S. , Zallo Eugenio , Trotta Rinaldo , Rastelli Armando , Schmidt Oliver G. , Benson Oliver 
Published: September 2019

AbstractHybrid interfaces between distinct quantum systems play a major role in the implementation of quantum networks. Quantum states have to be stored in memories to synchronize the photon arrival times for entanglement swapping by projective measurements in quantum repeaters or for entanglement purification. Here, we analyze the distortion of a single-photon wave packet propagating through a dispersive and absorptive medium with high spectral resolution. Single photons are generated from a single In(Ga)As quantum dot with its excitonic transition precisely set relative to the Cesium D1 transition. The delay of spectral components of the single-photon wave packet with almost Fourier-limited width is investigated in detail with a 200 MHz narrow-band monolithic Fabry-Pérot resonator. Reflecting the excited state hyperfine structure of Cesium, “slow light” and “fast light” behavior is observed. As a step towards room-temperature alkali vapor memories, quantum dot photons are delayed for 5 ns by strong dispersion between the two 1.17 GHz hyperfine-split excited state transitions. Based on optical pumping on the hyperfine-split ground states, we propose a simple, all-optically controllable delay for synchronization of heralded narrow-band photons in a quantum network.
Male mice, caged in the International Space Station for 35 days, sire healthy offspring
Authors: Matsumura Takafumi , Noda Taichi , Muratani Masafumi , Okada Risa , Yamane Mutsumi , Isotani Ayako , Kudo Takashi , Takahashi Satoru , Ikawa Masahito 
Published: September 2019

AbstractThe effect on the reproductive system and fertility of living in a space environment remains unclear. Here, we caged 12 male mice under artificial gravity (≈1 gravity) (AG) or microgravity (MG) in the International Space Station (ISS) for 35 days, and characterized the male reproductive organs (testes, epididymides, and accessory glands) after their return to earth. Mice caged on earth during the 35 days served as a “ground” control (GC). Only a decrease in accessory gland weight was detected in AG and MG males; however, none of the reproductive organs showed any overt microscopic defects or changes in gene expression as determined by RNA-seq. The cauda epididymal spermatozoa from AG and MG mice could fertilize oocytesin vitroat comparable levels as GC males. When the fertilized eggs were transferred into pseudo-pregnant females, there was no significant difference in pups delivered (pups/transferred eggs) among GC, AG, and MG spermatozoa. In addition, the growth rates and fecundity of the obtained pups were comparable among all groups. We conclude that short-term stays in outer space do not cause overt defects in the physiological function of male reproductive organs, sperm function, and offspring viability.
Chern insulator with a nearly flat band in the metal-organic-framework-based Kagome lattice
Authors: Baidya Santu , Kang Seungjin , Kim Choong H. , Yu Jaejun 
Published: September 2019

AbstractBased on first-principles density-functional theory (DFT) calculations, we report that the transition-metal bis-dithiolene, M3C12S12 (M = Mn and Fe), complexes can be a two-dimensional (2D) ferromagnetic insulator with nontrivial Chern number. Among various synthetic pathways leading to metal bis-dithiolenes, the simplest choice of ligand, Benzene-hexathiol, connecting metal cations to form a Kagome lattice is studied following the experimental report of time-reversal symmetric isostructural compound Ni3C12S12. We show sulfur and carbon-based ligands play the key role in making the complexes topologically nontrivial. An unusual topological quantum phase transition induced by the on-site Coulomb interaction brings a nearly flat band with a nonzero Chern number as the highest occupied band. With this analysis we explain the electronic structure of the class M3C12S12 and predict the existence of nearly flat band with nonzero Chern number and it can be a fractional Chern insulator candidate with carrier doping.