bluuebunny/crossref_metadata_2025 huggingface dataset:
Changing trends of river flows in the Upper Vistula Basin (East-Central Europe)
Authors: Górnik Marek
Published: February 2020

The mean annual, winter half-year and summer half-year flows at 86 water level gauges in the Upper Vistula Basin in the years 1951–2015 were examined. The Ward’s hierarchical cluster analysis was used for grouping sub-catchments in reference to the standardized aforementioned flows. Trends analysis was performed for each cluster of catchments in all combinations of periods not shorter than 20 years. Spatial distribution of clusters of catchments has been analysed according to geographical locations. There are observed different trends in distinguished groups of catchments, wherein the substantial differences concern long-term trends. Changes in trend direction in the years 1951–2015 were revealed, which indicate flow fluctuations. Presumably, physiographical heterogeneity of the Upper Vistula Basin is reflected in no unequivocal trends occurring in clusters of catchments. Some similarities were stated in short-term trends occurring in particular groups of catchments.
Mapping kindergartners’ quantitative competence
Authors: Van den Heuvel-Panhuizen Marja , Elia Iliada
Published: February 2020

In this study we investigated the structure of quantitative competence of kindergartners by testing a hypothesized four-factor model of quantitative competence consisting of the components counting, subitizing, additive reasoning and multiplicative reasoning. Data were collected from kindergartners in the Netherlands (n = 334) and in Cyprus (n = 304). A confirmatory factor analysis showed that the four-factor structure fitted the empirical data from the Netherlands. For the Cyprus data a one-factor structure was found to have a more adequate fit. Regarding the effect of country on performance, a comparison at item level showed that the kindergartners in the Netherlands outperformed those in Cyprus in the majority of quantitative competence items. Analyses of variance revealed for each country a significant effect of kindergarten year on performance, with children in K2 (second kindergarten year) outperforming those in K1 (first kindergarten year). A statistical implicative analysis at item level revealed that in both countries the relevant implicative chain, showing what successful solving of an item implies for correct solving of another item, reflects by and large the sequential steps mostly followed in teaching kindergartners early number. This sequence starts with counting and subitizing, then continues with additive reasoning and finally multiplicative reasoning. These implicative chains also clearly show that the development of early quantitative competence is not linear. There are many parallel processes and cross-connections between the components of quantitative competence.
Development of a novel model to predict HPAM viscosity with the effects of concentration, salinity and divalent content
Authors: Al-Hamairi Abdullah , AlAmeri Waleed
Published: February 2020

Polymer flooding has been established as an effective enhanced oil recovery (EOR) technique and can be utilized in large-scale field expansions. With high success rates and efficiency, polymer flooding operates by increasing the viscosity of water, promoting greater sweep efficiency and resulting in higher oil recovery beyond conventional waterflooding. Predicting viscosity has been established by numerous researchers as an essential tool to study polymers behavior under varying conditions. Previous model has proven a link between polymer viscosity and zero shear rate viscosity, relaxation time, hardness, and many other factors. This research initially reviews different types of polymers that can be applied successfully in EOR, demonstrate conditions that can alter polymer viscosity in porous medium, and analyze models that predict polymer bulk and in situ viscosity. The research then discusses a novel modification of the power law model to predict HPAM (SAV10) viscosity in a wide range of shear rates based on polymer concentration, fluid salinity, and divalent content. A polymer rheology study was carried out on SAV10 at various concentrations (750–5000 ppm) and brine salinities (43–210 k ppm). Results show the effectiveness of the model and the ability to predict viscosity accurately in low to medium shear rates, while in high shear rate, a slight deviation was noticeable.
Mechanical and biocompatible properties of polymer-infiltrated-ceramic-network materials for dental restoration
Authors: Cui Bencang , Zhang Ranran , Sun Fengbo , Ding Qian , Lin Yuanhua , Zhang Lei , Nan Cewen
Published: February 2020

Dental restorative materials with high mechanical properties and biocompatible performances are promising. In this work, polymer-infiltrated-ceramic-network materials (PICNs) were fabricated via infiltrating polymerizable monomers into porous ceramic networks and incorporated with hydroxyapatite nano-powders. Our results revealed that the flexural strength can be enhanced up to 157.32 MPa, and elastic modulus and Vickers hardness can be achieved up to 19.4 and 1.31 GPa, respectively, which are comparable with the commercial computer-aided design and computer-aided manufacturing (CAD/CAM) blocks. Additionally, the adhesion and spreading of rat bone marrow mesenchymal stem cells (rBMSCs) on the surface of such materials can be improved by adding hydroxyapatite, which results in good biocompatibility. Such PICNs are potential applicants for their application in the dental restoration.
Red-emitting YAG: Ce, Mn transparent ceramics for warm WLEDs application
Authors: Ling Junrong , Zhou Youfu , Xu Wentao , Lin He , Lu Shuai , Wang Bin , Wang Kun
Published: February 2020

A series of YAG:Ce,Mn transparent ceramics were prepared via a solid-state reaction-vacuum sintering method. The effects of various Mn2+–Si4+ pair doping levels on the structure, transmittance, and luminescence properties were systematically investigated. These transparent ceramics have average grain sizes of 10–16 μm, clean grain boundaries, and excellent transmittance up to 83.4% at 800 nm. Under the excitation of 460 nm, three obvious emission peaks appear at 533, 590, and 745 nm, which can be assigned to the transition 5d→4f of Ce 3+ and 4T1→6A1 of Mn2+. Thus, the Mn2+–Si4+ pairs can effectively modulate the emission spectrum by compensating broad orange-red and red spectrum component to yield high quality warm white light. After the optimized YAG:Ce,Mn transparent ceramic packaged with blue light-emitting diode (LED) chips, correlated color temperature (CCT) as low as 3723 K and luminous efficiency (LE) as high as 96.54 lm/W were achieved, implying a very promising candidate for application in white light-emitting diodes (WLEDs) industry.
Ubrogepant: First Approval
Authors: Scott Lesley J.
Published: February 2020

Ubrogepant (Ubrelvy™) is an orally administered, small molecule, highly-selective, calcitonin gene-related peptide (CGRP) antagonist that was developed by Allergan under license to Merck & Co. as an acute treatment for migraine. In December 2019, ubrogepant received its first global approval in the USA for the acute treatment of migraine (± aura) in adults. This article summarizes the milestones in the development of ubrogepant leading to its first global approval for the acute treatment of migraine (± aura) in adults.
To Defend or Not to Defend? How Responses to Negative Customer Review Affect Prospective customers’ Distrust and Purchase Intention
Authors: Zhao Haichuan , Jiang Lan , Su Chenting
Published: February 2020

Negative online reviews are a ubiquitous problem that affects every online seller at some point. It can lead to prospective consumers’ distrust and decrease future purchase intention. Therefore, formulating a proper response is essential for minimizing these negative effects. Based on the ability–motivation paradigm and stability attribution, we find that apology works better when the alleged cause is relatively unstable (e.g., competence-based negative review) and when the seller has a high ability to change. However, when the alleged cause is relatively stable (e.g., integrity-based negative review) or when the seller has a low ability to change, we show that it is better for the seller to defend its reputation. In addition, we demonstrate that a remedial action plan in the seller's response can reinforce the motivation to change communicated through apology. Thus, coupled with a remedial action plan, apology works better than defending one's reputation, regardless of the negative online review type.
Fourth graders’ (Re-)Reading, (historical) thinking, and (revised) writing about the black freedom movement
Authors: Bickford John H. , Clabough Jeremiah , Taylor Tim
Published: February 2020

Elementary teachers can integrate social studies into their curriculum through thematic or interdisciplinary units. This study explores fourth-grade students’ responses to a month-long, structured inquiry. For two weeks, fourth-graders engaged in multiple readings of five secondary and fourteen primary sources using closed- and open-ended analysis questions and extemporaneous, text-based writing. For another two weeks, the writing process guided students through concept mapping, skeleton outlining, peer- and teacher-review, and revision. Three researchers examined students’ writings for criticality, complexity, and clarity. Findings yielded positive, statistically significant correlations between secondary source usage and historical significance, secondary source usage and continuity-and-change, and primary source usage and contextualization. Positive, weak correlations appear between primary source usage and sourcing. No relationship appears between corroboration and other variables. Meaning is extrapolated for classroom practice and applied to seminal studies. Limitations include a small sample of largely homogeneous, inexperienced students.
Rural Finance, Capital Constrained Small Farms, and Financial Performance: Findings from a Primary Survey
Authors: Khanal Aditya R. , Omobitan Omobolaji
Published: February 2020

Capital and credit constraints limit the small farm’s ability to adequately use resources for optimum performance. Farmers’ access to capital is constrained in multiple ways, including price factors, risk factors, and transaction factors, as well as access to and ease of rural agricultural financing. Using a primary survey data of small farms in Tennessee, we analyzed factors influencing credit constraint and its impact on farm performance. Farm operators’ gender, off-farm work, land acreage holdings, farm specialization, and the use of smart phone with Internet significantly influenced credit constraint. We found that the financial performance of credit constrained small farmers was significantly lower than that of unconstrained small farmers—an adverse impact of constrained capacity to credit could result in up to $51,000 lower in gross farm sales. Additionally, our reason-specific results within credit constraint suggested that around $32,000 to $39,000 lower performance in gross sales can be attributable to the constrained borrowing with deficit to obtain agricultural loans at required or desired level.
Using Telemedicine in Mass Casualty Disasters
Authors: Gregory Megan E. , Sonesh Shirley C. , Hughes Ashley M. , Marttos Antonio , Schulman Carl I. , Salas Eduardo
Published: February 2020

Objectives:

The goal of this study is to test an implementation and examine users’ perceptions about the usefulness of telemedicine in mass casualty and disaster settings and to provide recommendations for using telemedicine in these settings.

Methods:

Ninety-two US Army Forward Surgical Team (FST) members participated in a high-fidelity mass casualty simulation at the Army Trauma Training Center (ATTC). Telemedicine was implemented into this simulation.

Results:

Only 10.9% of participants chose to use telemedicine. The most common users were surgeons and nurses. Participants believed it somewhat improved patient care, attainment of expert resources, decision-making, and adaptation, but not the timeliness of patient care. Participants reported several barriers to using telemedicine in the mass casualty setting, including (1) confusion around team roles, (2) time constraints, and (3) difficultly using in the mass casualty setting (eg, due to noise and other conditions).

Conclusions:

There appear to be barriers to the use and usefulness of telemedicine in mass casualty and disaster contexts. Recommendations include designating a member to lead the use of telemedicine, providing telemedical resources whose benefits outweigh the perceived cost in lost time, and ensuring telemedicine systems are designed for the conditions inherent to mass casualty and disaster settings.
Development and Validation of the Emotion Regulation Ability Test for Chinese Youth
Authors: Li Yi Ming , Li Jian , Zou Hong , Wei Shengnan
Published: February 2020

A culture- and age-appropriate instrument for measuring emotion regulation ability is needed for the research and practice of Chinese adolescents’ emotion regulation. This study developed and validated a situational judgment test of emotion regulation ability for Chinese youth (STER-CY). Three samples were recruited, and approximately 4380 5th- to 11th-grade students (but no 9th-grade students) participated in the study. Researchers collected emotional situations and responses based on the life of indigenous samples and examined the reliability and validity of the test scores. The results showed that Cronbach’s alpha and test–retest correlations provided evidence for the reliability of the test scores. Exploratory and confirmatory factor analysis supported unidimensionality. Construct validity was further verified by convergent and discriminant validity. Criteria-related validity was confirmed by the correlations between this test and some outcome variables related to emotion regulation. It was also found that girls scored higher on this test than boys did and that emotion regulation ability significantly increased from 5th to 7th grade, but it did not improve from 7th to 11th grade. Considered together, these findings showed that the STER-CY is a psychometrically sound measure of emotion regulation ability and can be used in future research and practice.
DEGREE-ONE MAHLER FUNCTIONS: ASYMPTOTICS, APPLICATIONS AND SPECULATIONS
Authors: COONS MICHAEL
Published: February 2020

We present a complete characterisation of the radial asymptotics of degree-one Mahler functions as $z$ approaches roots of unity of degree $k^{n}$, where $k$ is the base of the Mahler function, as well as some applications concerning transcendence and algebraic independence. For example, we show that the generating function of the Thue–Morse sequence and any Mahler function (to the same base) which has a nonzero Mahler eigenvalue are algebraically independent over $\mathbb{C}(z)$. Finally, we discuss asymptotic bounds towards generic points on the unit circle.
Transmission of Coxiella burnetii by ingestion in mice
Authors: Miller H. K. , Priestley R. A. , Kersh G. J.
Published: February 2020

Coxiella burnetii, the causative agent of Q fever, is widely present in dairy products around the world. It has been isolated from unpasteurised milk and cheese and can survive for extended periods of time under typical storage conditions for these products. Although consumption of contaminated dairy products has been suggested as a potential route for transmission, it remains controversial. Given the high prevalence of C. burnetii in dairy products, we sought to examine the feasibility of transmitting the major sequence types (ST16, ST8 and ST20) of C. burnetii circulating in the United States. We delivered three strains of C. burnetii, comprising each sequence type, directly into the stomachs of immunocompetent BALB/c mice via oral gavage (OG) and assessed them for clinical symptoms, serological response and bacterial dissemination. We found that mice receiving C. burnetii by OG had notable splenomegaly only after infection with ST16. A robust immune response and persistence in the stomach and mesenteric lymph nodes were observed in mice receiving ST16 and ST20 by OG, and dissemination of C. burnetii to peripheral tissues was observed in all OG infected mice. These findings support the oral route as a mode of transmission for C. burnetii.
Q fever seroprevalence in Australia suggests one in twenty people have been exposed
Authors: Gidding H. F. , Peng C. Q. , Graves S. , Massey P. D. , Nguyen C. , Stenos J. , Quinn H. E. , McIntyre P. B. , Durrheim D. N. , Wood N.
Published: February 2020

Q fever (caused by Coxiella burnetii) is thought to have an almost world-wide distribution, but few countries have conducted national serosurveys. We measured Q fever seroprevalence using residual sera from diagnostic laboratories across Australia. Individuals aged 1–79 years in 2012–2013 were sampled to be proportional to the population distribution by region, distance from metropolitan areas and gender. A 1/50 serum dilution was tested for the Phase II IgG antibody against C. burnetii by indirect immunofluorescence. We calculated crude seroprevalence estimates by age group and gender, as well as age standardised national and metropolitan/non-metropolitan seroprevalence estimates. Of 2785 sera, 99 tested positive. Age standardised seroprevalence was 5.6% (95% confidence interval (CI 4.5%–6.8%), and similar in metropolitan (5.5%; 95% CI 4.1%–6.9%) and non-metropolitan regions (6.0%; 95%CI 4.0%–8.0%). More males were seropositive (6.9%; 95% CI 5.2%–8.6%) than females (4.2%; 95% CI 2.9%–5.5%) with peak seroprevalence at 50–59 years (9.2%; 95% CI 5.2%–13.3%). Q fever seroprevalence for Australia was higher than expected (especially in metropolitan regions) and higher than estimates from the Netherlands (2.4%; pre-outbreak) and US (3.1%), but lower than for Northern Ireland (12.8%). Robust country-specific seroprevalence estimates, with detailed exposure data, are required to better understand who is at risk and the need for preventive measures.
Intraoperative echocardiographic coronary artery imaging in congenital and acquired heart disease
Authors: Yim Deane , Mertens Luc , Honjo Osami , Nield Lynne E.
Published: February 2020

Transoesophageal and epicardial echocardiography are indispensible intraoperative imaging modalities to guide paediatric heart disease surgeries and influence surgical decision-making. A less well-described role of intraoperative imaging is its utility in evaluating coronary artery patency and flow. Focused two-dimensional, colour, and spectral Doppler imaging of the coronary arteries should be performed during surgeries involving coronary manipulation or re-implantation, or in cases where there is unexpected ventricular dysfunction or electrographic signs concerning for ischaemia. Intraoperative imaging allows for any anatomical issues to be detected and addressed promptly in the operating room. Imaging of the coronary arteries should identify unobstructed coronary ostia and proximal course without kinking, angulation, narrowing, or significant calibre change to suggest stenosis or extrinsic compression from neighbouring structures. The aim of this review is to highlight the usefulness of transoesophageal and epicardial echocardiography in evaluating coronary artery patency and flow, provide a how-to guide for optimal imaging, and to introduce a practical guideline to achieve best clinical practice.
IDENTIFYING TECHNOLOGY SHOCKS AT THE BUSINESS CYCLE VIA SPECTRAL VARIANCE DECOMPOSITIONS
Authors: Lovcha Yuliya , Perez-Laborda Alejandro
Published: February 2020

In this paper, we identify the technology shock at business cycle frequencies to improve the performance of structural vector autoregression models in small samples. To this end, we propose a new identification method based on the spectral decomposition of the variance, which targets the contributions of the shock in theoretical models. Results from a Monte-Carlo assessment show that the proposed method can deliver a precise estimate of the response of hours in small samples. We illustrate the application of our methodology using US data and a standard Real Business Cycle model. We find a positive response of hours in the short run following a non-significant, near-zero impact. This result is robust to a large set of credible parameterizations of the theoretical model.
COMPUTATION OF ZEROS OF MONOTONE TYPE MAPPINGS: ON CHIDUME’S OPEN PROBLEM
Authors: DJITTE N. , MENDY J. T. , SOW T. M. M.
Published: February 2020

For $p\geq 2$, let $E$ be a 2-uniformly smooth and $p$-uniformly convex real Banach space and let $A:E\rightarrow E^{\ast }$ be a Lipschitz and strongly monotone mapping such that $A^{-1}(0)\neq \emptyset$. For given $x_{1}\in E$, let $\{x_{n}\}$ be generated by the algorithm $x_{n+1}=J^{-1}(Jx_{n}-\unicode[STIX]{x1D706}Ax_{n})$, $n\geq 1$, where $J$ is the normalized duality mapping from $E$ into $E^{\ast }$ and $\unicode[STIX]{x1D706}$ is a positive real number in $(0,1)$ satisfying suitable conditions. Then it is proved that $\{x_{n}\}$ converges strongly to the unique point $x^{\ast }\in A^{-1}(0)$. Furthermore, our theorems provide an affirmative answer to the Chidume et al. open problem [‘Krasnoselskii-type algorithm for zeros of strongly monotone Lipschitz maps in classical Banach spaces’, SpringerPlus4 (2015), 297]. Finally, applications to convex minimization problems are given.
SOME FRESH AIR INTO THE NEOPYTHAGOREAN TRADITION: THE FRAGMENTS FROMON KINGSHIPBY DIOTOGENES
Authors: Roskam Geert
Published: February 2020

The Neopythagorean Diotogenes, author of a lost treatiseOn Kingshipof which some fragments have come down to us in Stobaeus’Anthology, is a largely neglected writer. Scholars either ignore him or briefly discuss him in the context of general overviews of Greek political thinking, usually comparing him to other Neopythagoreans such as Sthenidas and Ecphantus. This article argues that Diotogenes deserves to be read for his own sake, as a creative and subtle thinker who managed to contribute to his own philosophical tradition by benefiting from Homeric exegesis and by taking into account the more concrete demands of daily life.
High dietary acid load score is not associated with the risk of metabolic syndrome in Iranian adults
Authors: Mohammadifard Noushin , Karimi Golgis , Khosravi Alireza , Sarrafzadegan Nizal , Jozan Mahnaz , Zahed Parvaneh , Haghighatdoost Fahimeh
Published: February 2020

Abstract. Background and objective: The association between dietary acid load and metabolic syndrome (MetS) risk is not well-known. Therefore, we aimed to investigate the relationship between dietary acid load and the risk of MetS among Iranian adults. Methods: This cross-sectional study was carried out on 1430 Iranian adults. Dietary intakes were assessed using a validated food frequency questionnaire. Dietary acid load was estimated using potential renal acid load (PRAL) and net endogenous acid production (NEAP). MetS was defined according to the ATP-III criteria. The risk of MetS and its components was explored using logistic regression test. Results: Totally, 205 individuals were identified to have MetS. No significant association for MetS was found across the quartiles of PRAL and NEAP either in the crude model [Q4 PRAL: OR (95% CI): 0.94 (0.67–1.32), and NEAP: OR (95% CI): 0.88 (0.63–1.25)] or fully-adjusted model [Q4 PRAL: OR (95% CI): 0.90 (0.61–1.33), and NEAP: OR (95% CI): 1.05 (0.70–1.57)]. Amongst the components of MetS, higher scores of NEAP was associated with an increased risk of impaired blood sugar after adjustment for potential confounders [OR (95% CI): 1.35 (0.93–1.96)]. No significant association was found for other components either with PRAL or with NEAP. Conclusion: Our findings suggest no association between dietary acid load and MetS risk in Iranian adults. However, higher dietary acid load, measured by NEAP, but not PRAL, was associated with increased risk of impaired fasting blood sugar. Longitudinal studies are warranted to explore whether a diet low in potential acid load could reduce MetS risk.
Rezidivierende urogynäkologische Infektionen
Authors: Betschart Cornelia , Dedes Ioannis , Scheiner David
Published: February 2020

Zusammenfassung. Veränderungen im urogenitalen Mikrobiom der Blase, Urethra, Vagina und Zervix können Ursache für wiederkehrende Infektionen sein. Dabei muss zwischen obligat und fakultativ pathogenen Keimen unterschieden werden. Bei den fakultativ pathogenen Keimen soll nur beim Vorliegen von zuordenbaren Symptomen antibiotisch, antiviral oder antimykotisch behandelt werden. Sexuell übertragbare Erkrankungen manifestieren sich bei Frauen isoliert urogenital oder als aufsteigender Infekt («pelvic inflammatory disease»). Sexuell übertragbare Erkrankungen (z.B. Chlamydieninfektion) können asymptomatisch verlaufen oder mit einer hohen Symptomlast, Lebensqualitätseinschränkung oder Sterilität einhergehen. Dieser Minireview gibt einen Überblick über die Pathogenität und Behandlung der verschiedenen Erreger.
Jeder hat doch Rückenschmerzen: degenerative lumbale Wirbelsäulenerkrankungen und ihre Behandlungsmöglichkeiten
Authors: Fortunati Mathias , Rossi-Mossuti Frédéric , Muroi Carl
Published: February 2020

Zusammenfassung. Rückenschmerzen sind eine der verbreitetsten Volkskrankheiten. Rund 84 % aller Menschen leiden zumindest einmal in ihrem Leben daran. Unspezifische Rückenschmerzen werden konservativ behandelt. Unterstützend können interventionelle schmerztherapeutische Verfahren, i.e. Infiltrationen, angewendet werden. Operationen bei rein lumbalen Schmerzen sollten nur in Ausnahmefällen erfolgen. Häufig zeigen sich aber auch zusätzliche neurologische Symptome, wie z.B. ein Ausstrahlen, i.e. Ischialgie. Typische Ursachen sind Diskushernien oder die – aufgrund der erhöhten Lebenserwartung immer häufiger auftretende – Spinalkanalstenose. Operationen bei Versagen der konservativen Therapiemassnahmen zeigen hier eine bessere Prognose. Bei schweren neurologischen Symptomen ist eine operative Behandlung angezeigt. Osteoporotische Wirbelkörperfrakturen führen zu akuten Rückenchmerzen. Hier muss anhand klarer Richtlinien entschieden werden, ob eine operative Behandlung im Sinne einer Vertebro- oder Kyphoplastie erfolgen soll oder nicht.
Monitoring Intraseasonal Oscillations in the Indian Ocean Using Satellite Observations
Authors: Roman‐Stork Heather L. , Subrahmanyam Bulusu , Trott Corinne B.
Published: February 2020

Intraseasonal oscillations (ISOs) in the Indian Ocean play a significant role in determining the active (wet) and break (dry) cycles of the southwest monsoon rainfall. In this study, we use satellite‐derived precipitation, sea level anomalies (SLAs), sea surface salinity (SSS), sea surface temperature, and surface winds to monitor the 30‐90‐day, 10‐20‐day, and 3‐7‐day ISOs, and how they influence local dynamics. The main focus of this work, however, is showing the importance of using SLA and SSS to monitor ISOs. Mixed Rossby gravity waves were found to induce convection associated with the southern cell of the 10‐20‐day mode, with surface winds from the northern cell modulating coastal Kelvin waves in the Bay of Bengal. The 10‐20‐day SSS response is instead more closely related to wind‐induced upwelling in the central Bay of Bengal and river runoff in the northern Bay. The 3‐7‐day mode was found to have a weak oceanic signal, as the monsoon trough is mainly positioned over land, though SSS captured the structure of the signal most clearly. This study highlights the need for high spatial resolution SLA in order to adequately capture 3‐7‐day oscillations in the monsoon trough.
Seasonal Shift From Biogenic to Geogenic Fluvial Carbon Caused by Changing Water Sources in the Wet‐Dry Tropics
Authors: Duvert Clément , Hutley Lindsay B. , Birkel Christian , Rudge Mitchel , Munksgaard Niels C. , Wynn Jonathan G. , Setterfield Samantha A. , Cendón Dioni I. , Bird Michael I.
Published: February 2020

The riverine export of carbon is expected to be driven by changes in connectivity between source areas and streams. Yet we lack a thorough understanding of the relative contributions of different water sources to the dissolved carbon flux, and of the way these contributions vary with seasonal changes in flow connectivity. Here we assess the temporal variations in water and associated dissolved inorganic carbon (DIC) sources and fluxes in a wet‐dry tropical river of northern Australia over two years. We use linear mixing models integrated into a Bayesian framework to determine the relative contributions of rainfall, seasonal wetlands, shallow groundwater, and a deep carbonate aquifer to riverine DIC fluxes, which we relate to the age of water sources. Our results suggest extreme shifts in water and DIC sources between the wet and dry seasons. Under wet conditions, most DIC was of biogenic origin and transported by relatively young water sources originating from shallow groundwater and wetlands. As rainfall ceased, the wetlands either dried out or became disconnected from the stream network. From this stage, DIC switched to a geogenic origin, nearly entirely conveyed via older water sources from the carbonate formation. Our findings demonstrate the importance of changing patterns of connectivity when evaluating riverine DIC export from catchments. This work also illustrates the need to systematically partition DIC fluxes between biogenic and geogenic sources, if we are to quantify how the riverine export of carbon affects net carbon soil storage.
Subdaily‐Scale Chemical Variability in a Torreites Sanchezi Rudist Shell: Implications for Rudist Paleobiology and the Cretaceous Day‐Night Cycle
Authors: de Winter Niels J. , Goderis Steven , Van Malderen Stijn J.M. , Sinnesael Matthias , Vansteenberge Stef , Snoeck Christophe , Belza Joke , Vanhaecke Frank , Claeys Philippe
Published: February 2020

This study presents subdaily resolved chemical records through fossil mollusk shell calcite. Trace element profiles resolve periodic variability across ~40‐μm‐thin daily growth laminae in a Campanian Torreites sanchezi rudist bivalve. These high‐resolution records are combined with seasonally resolved stable isotope and trace element records that allow shell‐chemical variability to be discussed on both seasonal and daily scale. A combination of layer counting, spectral analysis of chemical cyclicity and chemical layer counting shows that the rudist precipitated 372 daily laminae per year, demonstrating that length of day has increased since the Late Cretaceous, as predicted by astronomical models. This new approach to determine the length of a solar day in geologic history through multiproxy chemical records at subdaily resolution yields considerably more control on the uncertainty of this estimate. Daily chemical variability exceeds seasonal variability in our records, and cannot be explained by diurnal temperature changes. Instead, we postulate that rudist shell chemistry is driven on a daily scale by changes in light intensity. These results together with those of stable isotope analyses provide strong evidence that Torreites rudists had photosymbionts. Bivalve shell calcite generally preserves well. Therefore, this study paves the way for daily‐scale reconstructions of paleoenvironment and sunlight intensity on geologic time scales from bivalve shells, potentially allowing researchers to bridge the gap between climate and weather reconstructions. Such reconstructions improve shell chronologies, document environmental change in warm ecosystems, and widen our understanding of the magnitude of short‐term changes during greenhouse climates.
Raw Signal Simulation of Synthetic Aperture Radar Altimeter Over Complex Terrain Surfaces
Authors: Zhu Zhanyu , Zhang Hai , Xu Feng
Published: February 2020

In comparison with the conventional radar altimeter, synthetic aperture radar altimeter (SRAL) is developed with better along‐track spatial resolution and height precision. When SRAL improves the performance of height measurement, it also complicates the radar system designing, signal processing, data analyzing, and system testing. The SRAL raw signal is the result of the interaction between the transmitted signal and the complex terrain surfaces. Generally, the SRAL is used in ocean applications since the PDF can be derived from different ocean surfaces. However, the actual acquired SRAL waveforms can be from complex and variable surface, which may include mountains, cities, forests, lakes, and other types of terrain surfaces. These waveforms contain information about the surfaces of the Earth although difficult to analyze. This paper focuses on the study of the raw signal simulation of SRAL for complex terrain surfaces including land surfaces. The principle of radar altimeter, the electromagnetic characteristics of land targets, and the SRAL signal processing are analyzed. The geometric models are extracted from digital elevation model, and the scattering characteristics of the terrain surface are established with three scattering models. Finally, three cases of terrain surfaces, namely, ice surface, mountain area, and urban area, are simulated and validated against actual SRAL signals measured by the Sentinel‐3 SRAL sensor.
An UAV Wireless Communication Noise Suppression Method Based on OFDM Modulation and Demodulation
Authors: Jia Yinsen , Tu Xinqi , Yan Wei
Published: February 2020

In view of the problem that the unmanned aerial vehicle (UAV) communication link is vulnerable to strong electromagnetic pulse generated by lightning or high‐voltage transmission lines in the complex electromagnetic environment, the influence of the electromagnetic pulse generated by the high‐voltage transmission line of the EFT electromagnetic pulse and the surge electromagnetic pulse on wireless communication link are analyzed in this paper. When those electromagnetic pulse's noise field strength is 500 V/m, the bit‐error‐rate of the communication link is increased to 45.39%, 45.39%, and 46.10%, respectively, indicating that surge pulse has the strongest influence on the communication link. Therefore, a UAV noise suppression method based on the principle of orthogonal frequency‐division multiplexing (OFDM) modulation and demodulation and dual antenna design has been proposed in this paper. This method is used to filter out electromagnetic impulse noise after wireless signal reception, and then demodulate to achieve the goal of noise suppression. Applying the method to a certain type of UAV based on OFDM modulation and demodulation, and theoretical analysis and simulation results show that the proposed method can effectively suppress the electromagnetic pulse generated by high‐voltage transmission lines, EFT electromagnetic pulse, surge electromagnetic pulse, the bit‐error‐rate dropped to 0.005597%, 0.004531%, 0.005597%, respectively.
Insights into the bioavailability of oceanic dissolved Fe from phytoplankton uptake kinetics
Authors: Shaked Yeala , Buck Kristen N , Mellett Travis , Maldonado Maria T
Published: February 2020

Phytoplankton growth in large parts of the world ocean is limited by low availability of dissolved iron (dFe), restricting oceanic uptake of atmospheric CO2. The bioavailability of dFe in seawater is however difficult to appraise since it is bound by a variety of poorly characterized organic ligands. Here, we propose a new approach for evaluating seawater dFe bioavailability based on its uptake rate constant by Fe-limited cultured phytoplankton. We utilized seven phytoplankton species of diverse classes, sizes, and provenances to probe for dFe bioavailability in 12 seawater samples from several ocean basins and depths. All tested phytoplankton acquired organically bound Fe in any given sample at similar rates (after normalizing to cellular surface area), confirming that multiple, Fe-limited phytoplankton species can be used to probe dFe bioavailability in seawater. These phytoplankton-based uptake rate constants allowed us to compare water types, and obtain a grand average estimate of seawater dFe bioavailability. Among water types, dFe bioavailability varied by approximately four-fold, and did not clearly correlate with Fe concentrations or any of the measured Fe speciation parameters. Compared with well-studied Fe complexes, seawater dFe is more available than model siderophore Fe, but less available than inorganic Fe. Exposure of seawater to sunlight, however, significantly enhanced dFe bioavailability. The rate constants established in this work, not only facilitate comparison between water types, but also allow calculation of Fe uptake rates by phytoplankton in the ocean based on measured dFe concentrations. The approach established and verified in this study, opens a new way for determining dFe bioavailability in samples across the ocean, and enables modeling of in situ Fe uptake rates by phytoplankton using dFe concentrations from GEOTRACES datasets.
TfR1 binding with H-ferritin nanocarrier achieves prognostic diagnosis and enhances the therapeutic efficacy in clinical gastric cancer
Authors: Cheng Xiaojing , Fan Kelong , Wang Lin , Ying Xiangji , Sanders Andrew J. , Guo Ting , Xing Xiaofang , Zhou Meng , Du Hong , Hu Ying , Ding Huirong , Li Ziyu , Wen Xianzi , Jiang Wenguo , Yan Xiyun , Ji Jiafu
Published: February 2020

H-ferritin (HFn) nanocarrier is emerging as a promising theranostic platform for tumor diagnosis and therapy, which can specifically target tumor cells via binding transferrin receptor 1 (TfR1). This led us to investigate the therapeutic function of TfR1 in GC. The clinical significance of TfR1 was assessed in 178 GC tissues by using a magneto-HFn nanoparticle-based immunohistochemistry method. The therapeutic effects of doxorubicin-loaded HFn nanocarriers (HFn-Dox) were evaluated on TfR1-positive GC patient-derived xenograft (GC-PDX) models. The biological function of TfR1 was investigated through in vitro and in vivo assays. TfR1 was upregulated (73.03%) in GC tissues, and reversely correlated with patient outcome. TfR1-negative sorted cells exhibited tumor-initiating features, which enhanced tumor formation and migration/invasion, whereas TfR1-positive sorted cells showed significant proliferation ability. Knockout of TfR1 in GC cells also enhanced cell invasion. TfR1-deficient cells displayed immune escape by upregulating PD-L1, CXCL9, and CXCL10, when disposed with IFN-γ. Western blot results demonstrated that TfR1-knockout GC cells upregulated Akt and STAT3 signaling. Moreover, in TfR1-positive GC-PDX models, the HFn-Dox group significantly inhibited tumor growth, and increased mouse survival, compared with that of free-Dox group. TfR1 could be a potential prognostic and therapeutic biomarker for GC: (i) TfR1 reversely correlated with patient outcome, and its negative cells possessed tumor-aggressive features; (ii) TfR1-positive cells can be killed by HFn drug nanocarrier. Given the heterogeneity of GC, HFn drug nanocarrier combined with other therapies toward TfR1-negative cells (such as small molecules or immunotherapy) will be a new option for GC treatment.
Friendship paradox biases perceptions in directed networks
Authors: Alipourfard Nazanin , Nettasinghe Buddhika , Abeliuk Andrés , Krishnamurthy Vikram , Lerman Kristina
Published: February 2020

Social networks shape perceptions by exposing people to the actions and opinions of their peers. However, the perceived popularity of a trait or an opinion may be very different from its actual popularity. We attribute this perception bias to friendship paradox and identify conditions under which it appears. We validate the findings empirically using Twitter data. Within posts made by users in our sample, we identify topics that appear more often within users’ social feeds than they do globally among all posts. We also present a polling algorithm that leverages the friendship paradox to obtain a statistically efficient estimate of a topic’s global prevalence from biased individual perceptions. We characterize the polling estimate and validate it through synthetic polling experiments on Twitter data. Our paper elucidates the non-intuitive ways in which the structure of directed networks can distort perceptions and presents approaches to mitigate this bias.
Estimating growth patterns and driver effects in tumor evolution from individual samples
Authors: Salichos Leonidas , Meyerson William , Warrell Jonathan , Gerstein Mark
Published: February 2020

Tumors accumulate thousands of mutations, and sequencing them has given rise to methods for finding cancer drivers via mutational recurrence. However, these methods require large cohorts and underperform for low recurrence. Recently, ultra-deep sequencing has enabled accurate measurement of VAFs (variant-allele frequencies) for mutations, allowing the determination of evolutionary trajectories. Here, based solely on the VAF spectrum for an individual sample, we report on a method that identifies drivers and quantifies tumor growth. Drivers introduce perturbations into the spectrum, and our method uses the frequency of hitchhiking mutations preceding a driver to measure this. As validation, we use simulation models and 993 tumors from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium with previously identified drivers. Then we apply our method to an ultra-deep sequenced acute myeloid leukemia (AML) tumor and identify known cancer genes and additional driver candidates. In summary, our framework presents opportunities for personalized driver diagnosis using sequencing data from a single individual.
MTR4 drives liver tumorigenesis by promoting cancer metabolic switch through alternative splicing
Authors: Yu Lili , Kim Jinchul , Jiang Lei , Feng Bingbing , Ying Yue , Ji Kai-yuan , Tang Qingshuang , Chen Wancheng , Mai Taoyi , Dou Wenlong , Zhou Jianlong , Xiang Le-yang , He Yang-fan , Yang Dinghua , Li Qingjiao , Fu Xuemei , Xu Yang
Published: February 2020

The metabolic switch from oxidative phosphorylation to glycolysis is required for tumorigenesis in order to provide cancer cells with energy and substrates of biosynthesis. Therefore, it is important to elucidate mechanisms controlling the cancer metabolic switch. MTR4 is a RNA helicase associated with a nuclear exosome that plays key roles in RNA processing and surveillance. We demonstrate that MTR4 is frequently overexpressed in hepatocellular carcinoma (HCC) and is an independent diagnostic marker predicting the poor prognosis of HCC patients. MTR4 drives cancer metabolism by ensuring correct alternative splicing of pre-mRNAs of critical glycolytic genes such as GLUT1 and PKM2. c-Myc binds to the promoter of the MTR4 gene and is important for MTR4 expression in HCC cells, indicating that MTR4 is a mediator of the functions of c-Myc in cancer metabolism. These findings reveal important roles of MTR4 in the cancer metabolic switch and present MTR4 as a promising therapeutic target for treating HCC.
Initiation of a stable convective hydroclimatic regime in Central America circa 9000 years BP
Authors: Winter Amos , Zanchettin Davide , Lachniet Matthew , Vieten Rolf , Pausata Francesco S. R. , Ljungqvist Fredrik Charpentier , Cheng Hai , Edwards R. Lawrence , Miller Thomas , Rubinetti Sara , Rubino Angelo , Taricco Carla
Published: February 2020

Many Holocene hydroclimate records show rainfall changes that vary with local orbital insolation. However, some tropical regions display rainfall evolution that differs from gradual precessional pacing, suggesting that direct rainfall forcing effects were predominantly driven by sea-surface temperature thresholds or inter-ocean temperature gradients. Here we present a 12,000 yr continuous U/Th-dated precipitation record from a Guatemalan speleothem showing that Central American rainfall increased within a 2000 yr period from a persistently dry state to an active convective regime at 9000 yr BP and has remained strong thereafter. Our data suggest that the Holocene evolution of Central American rainfall was driven by exceeding a temperature threshold in the nearby tropical oceans. The sensitivity of this region to slow changes in radiative forcing is thus strongly mediated by internal dynamics acting on much faster time scales.
Genetic influence is linked to cortical morphology in category-selective areas of visual cortex
Authors: Abbasi Nooshin , Duncan John , Rajimehr Reza
Published: February 2020

Human visual cortex contains discrete areas that respond selectively to specific object categories such as faces, bodies, and places. A long-standing question is whether these areas are shaped by genetic or environmental factors. To address this question, here we analyzed functional MRI data from an unprecedented number (n = 424) of monozygotic (MZ) and dizygotic (DZ) twins. Category-selective maps were more identical in MZ than DZ twins. Within each category-selective area, distinct subregions showed significant genetic influence. Structural MRI analysis revealed that the ‘genetic voxels’ were predominantly located in regions with higher cortical curvature (gyral crowns in face areas and sulcal fundi in place areas). Moreover, we found that cortex was thicker and more myelinated in genetic voxels of face areas, while it was thinner and less myelinated in genetic voxels of place areas. This double dissociation suggests a differential development of face and place areas in cerebral cortex.
Experimental evidence of long-term oceanic circulation reversals without wind influence in the North Ionian Sea
Authors: Rubino Angelo , Gačić Miroslav , Bensi Manuel , Kovačević Vedrana , Malačič Vlado , Menna Milena , Negretti Maria Eletta , Sommeria Joël , Zanchettin Davide , Barreto Ricardo V. , Ursella Laura , Cardin Vanessa , Civitarese Giuseppe , Orlić Mirko , Petelin Boris , Siena Giuseppe
Published: February 2020

Under the emerging features of interannual-to-decadal ocean variability, the periodical reversals of the North Ionian Gyre (NIG), driven mostly by the mechanism named Adriatic-Ionian Bimodal Oscillating System (BiOS), are known as impacting on marine physics and biogeochemistry and potentially influencing short-term regional climate predictability in the Eastern Mediterranean. Whilst it has been suggested that local wind forcing cannot explain such variability, aspects of the alternative hypothesis indicating that NIG reversals mainly arises from an internal ocean feedback mechanism alone remain largely debated. Here we demonstrate, using the results of physical experiments, performed in the world’s largest rotating tank and numerical simulations, that the main observed feature of BiOS, i.e., the switch of polarity of the near-surface circulation in the NIG, can be induced by a mere injection of dense water on a sloping bottom. Hence, BiOS is a truly oceanic mode of variability and abrupt polarity changes in circulation can arise solely from extreme dense water formation events.
Relative Average Look Duration and its Association with Neurophysiological Activity in Young Children with Autism Spectrum Disorder
Authors: Isaev Dmitry Yu. , Major Samantha , Murias Michael , Carpenter Kimberly L. H. , Carlson David , Sapiro Guillermo , Dawson Geraldine
Published: February 2020

Autism Spectrum Disorder (ASD) is characterized by early attentional differences that often precede the hallmark symptoms of social communication impairments. Development of novel measures of attentional behaviors may lead to earlier identification of children at risk for ASD. In this work, we first introduce a behavioral measure, Relative Average Look Duration (RALD), indicating attentional preference to different stimuli, such as social versus nonsocial stimuli; and then study its association with neurophysiological activity. We show that (1) ASD and typically developing (TD) children differ in both (absolute) Average Look Duration (ALD) and RALD to stimuli during an EEG experiment, with the most pronounced differences in looking at social stimuli; and (2) associations between looking behaviors and neurophysiological activity, as measured by EEG, are different for children with ASD versus TD. Even when ASD children show attentional engagement to social content, our results suggest that their underlying brain activity is different than TD children. This study therefore introduces a new measure of social/nonsocial attentional preference in ASD and demonstrates the value of incorporating attentional variables measured simultaneously with EEG into the analysis pipeline.