bluuebunny/crossref_metadata_2025_split huggingface dataset:
A density functional theory (DFT) study of the doping effect on 4-[2-(2-N, N-dihydroxy amino thiophene) vinyl] benzenamine
Authors: Mveme Côme Damien Désiré , Tchangnwa Nya Fridolin , Ejuh Geh Wilson , Ndjaka Jean Marie Bienvenu 
Published: February 2021

AbstractIn the present work, density functional theory was used at the B3LYP, CAM-B3LYP and B3PW91 levels with the 6–311 +  + G (d, p) basis set, in other to study the structural, optoelectronic, nonlinear optical, piezoelectric and thermodynamic properties of 4-[2-(2-N, N-dihydroxy amino thiophene) vinyl] benzenamine (DATVB) molecule doped with chlorine and fluorine respectively. The results obtained show that doping significantly improves the properties of this material. The materials obtained after doping 4-[2-(2-(5-(bis (chlorooxy) amino) thiophene) vinyl] benzenamine (BCATVB) and 4-[2-(2-(5-(bis (fluorooxy) amino) thiophene) vinyl] benzenamine (BFATVB) are good semiconductors because their gap energy is range between 1 and 1.5 eV which is less than 3 ev. Their first order hyperpolarizabilities ($${\beta }_{mol}$$

β

mol

) are very high compared to para-nitroaniline (p-NA) known as reference molecule for nonlinear optical properties. The obtained results predisposes them as good nonlinear optical materials with applications in photonics, optical signal processing devices, dynamic imaging, data storage and computer devices. The piezoelectric and pyroelectric coefficients of the fluorinated molecule are higher than those of the reference organic molecule polyvinylidene fluoride. This led us to the conclusion that, these molecules can also be used for applications in piezoelectricity.
Exponent determination in a poorly gauged basin system in Nigeria based on flow characteristics investigation and regionalization method
Authors: Fasipe O. A. , Izinyon O. C. 
Published: February 2021

AbstractIn this study, a method for estimating the exponent “n” values of the catchment-area equations of four sub-basins within the poorly gauged Benin-Owena River Basin Development Authority (BORBDA) in Nigeria is presented to enable the estimation of flows at ungauged sites within the basin and the determination of small hydropower (SHP) potential at different locations in each sub-basin and the entire basin. Optimal prediction of streamflow characteristics in poorly gauged basin requires developing a methodology for extrapolation of data from gauged to ungauged sites within the basin. Four sub-catchments of BORBDA, a poorly gauged basin in Nigeria, were investigated using Remote Sensing (RS), Geographic Information System (GIS), statistical techniques, and Natural Resources Conservation Service-Curve Number (NRCS-CN) hydrological model. Discharge values at gauged sites (Qg) were obtained from recorded discharge values collected for 12 months at an established gauging station in each sub-basin. RS and GIS techniques were used to develop classification maps and obtain crucial data like curve number (CN), elevation, Hydrologic Soil Group (HSG), rainfall intensity, slope, area of gauged and ungauged required for evaluating spatial discharge (ungauged) utilizing NRCS-CN model. From the established model for each sub-basin, exponent “n” in the relationship between discharge and catchment area was obtained to be 0.23, 0.41, 0.71, and 0.74. Using the lumped modeling approach, which considers a watershed as a single unit for computation, where watershed parameters and variables were to be averaged produced “n” = 0.52 for BORBDA area, which is within the range of 0.5–0.85 suggested by previous researchers. Obtained BORBDA exponent “n” was validated for use in the entire basin through soil homogeneity test by generating BORBDA soil map which confirms the four sub-basins investigated share similar HSG A, B, and D with BORBDA. The exponent “n” value is useful for predicting flows in ungauged parts of the basin. The exponent “n” value obtained for the basin is helpful in the assessment of discharge and determination of SHP potential at different locations within the poorly gauged BORBDA basin, and the dissemination of the research findings will find practical use and guide to practicing hydrologists in Nigeria and locations around the world with similar challenges of poorly gauged basins particularly Africa and other developing countries.
Stochastic optimization and modeling of high-velocity impact tests on high-temperature carbon–carbon composites
Authors: Aktaş Latif Tibet , Aydın Levent 
Published: February 2021

AbstractIn this study, it is intended to optimize a high-velocity impact case of a composite plate. The case selected from literature focused on the failure response of advanced carbon–carbon (C/C) composites under high-velocity impacts. Based on the stochastic optimization method, three unique models are introduced within the present study's scope as dimensionless damage areas of front and back sides and the composite impact energy response. The difference between the equations found in the present study and the base study is the number of variables. Obtained prediction models consist of only the tests' input variables; thus, these models can be considered the essential prediction functions of high-velocity impact response of C/C composites under high temperatures. Multiple nonlinear regression method is used for objective functions of the optimization problem. Since the determination coefficient values have been found quite similar to the ones in the literature, the presented models can be considered successful in predicting the results. By utilizing the novel regression functions presented in this study, the damaged areas are minimized. Without the necessity of experimental research, further predictions can be made by operating the models found in the present study.
Voltage and frequency control in conventional and PV integrated power systems by a particle swarm optimized Ziegler–Nichols based PID controller
Authors: Ghosh Arabinda , Ray Anjan Kumar , Nurujjaman Md. , Jamshidi Mo 
Published: February 2021

AbstractVariations of load demands, expansion of power system by interconnections among different areas and integration of renewable energy sources bring new challenges for stable, reliable and uninterrupted operations of power systems. In this paper, a control technique is proposed to control and optimize the performances of the three models having importance in the present and future energy systems. These are the output variations of an automatic voltage regulation (AVR) system, frequency variations in a load frequency control (LFC) system of a thermal power plant and frequency variations of a PV integrated thermal power plant. The proposed controller is a particle swarm optimized Ziegler–Nichols (ZN) method based proportional-integral-derivative (PID) controller. A particle swarm optimization (PSO) method suffers from the unavailability of prior knowledge of initial values of parameters. Whereas, the classical ZN method leaves the scope for performance improvements of a system. A rejuvenation to the classical ZN method is proposed by integrating PSO. The combined effect optimizes the voltage and the frequency performances, while ensuring system stability. Additionally, different objective functions inspired from energy industry requirements are considered to demonstrate performance improvements of the systems (e.g. maximum overshoot, steady-state error, settling time). The robustness of the proposed method is demonstrated by considering parametric uncertainty in the system. The proposed method is compared with performances of different controllers (e.g. PI, fuzzy PI, fuzzy PID), different iterative soft computing methods (e.g. pattern search, artificial bee colony, different variants of PSO) and classical optimization method (e.g. linear matrix inequality) considering different objective functions and different load disturbances for the aforementioned models. It is also observed that better performances are obtained using a significantly less number of iterations.
Time to Work—Opposing Political Rationality with Young Peoples’ Experiences of Working in a Mandatory Activation Context in Norway
Authors: Gjersøe Heidi Moen , Leseth Anne 
Published: February 2021

AbstractThis paper argues that young people, targeted by activation policies, had several temporal experiences with work that can contribute to broadening our understanding of labour market policy for this group of young people. By drawing on qualitative interviews with young people not in employment, education, or training (NEET) in a Norwegian activation context, and by applying anthropological and sociological concepts on temporality and work time in our analysis, we question how time is constructed and reproduced in the establishment of work relations among this group of people. We argue that political discourses of work inclusion for young adults (NEETs) tend to portray work as a means to an end for inclusion. In doing so, they fail to address the complex temporal dimension of work. We find that young adults have a range of complex experiences where disparity between formal and informal aspects of work becomes visible. The temporal dimension of these experiences and the relativity of speed in getting a job are not experienced in a linear manner but as churning between getting a job, having a job, and losing a job.
The Role of Disgust and Threat in Contamination-Related Obsessive–Compulsive Disorder
Authors: Mulheron Leanne , Jones Mairwen K. 
Published: February 2021

AbstractTheoretical models suggest that the emotion disgust or threat overestimates are important in the aetiology and maintenance of contamination-based obsessive–compulsive disorder. In the current study, both threat and disgust were manipulated and 115 non-clinical participants (mean age 20.46 years, 94 females) were randomly allocated to one of four conditions: high-disgust/low-threat (n = 29), high-disgust/high-threat (n = 29), low-disgust/low-threat (n = 27), and low-disgust/high-threat (n = 30). Participants completed a hierarchical Behavioural Avoidance Task (BAT). Those in the high-threat and high-disgust conditions completed less BAT steps and showed more latency to begin each step than those in the low-threat and low-disgust conditions. A significant interaction effect was observed for the high-disgust/high-threat condition as significantly more task avoidance was found. However, handwashing duration was not significantly different between the high and low-disgust conditions or the high and low-threat conditions. The overall low mean washing duration of 30 s possibly due to the testing conditions and/or the ethnic heterogeneity of the sample may account for these results. There were also no significant differences in the level of anxiety for participants in the high-threat compared with the low-threat conditions. It is possible that anxiety remained relatively low across conditions as a result of the graduated BAT. Future research and theoretical and clinical implications are discussed.
Strategic non-nuclear weapons and the onset of a Third Nuclear Age
Authors: Futter Andrew , Zala Benjamin 
Published: February 2021

AbstractThree decades after what is widely referred to as the transition from a First to a Second Nuclear Age, the world stands on the cusp of a possible Third Nuclear Age where the way that we conceptualise the central dynamics of the nuclear game will change again. This paradigm shift is being driven by the growth and spread of non-nuclear technologies with strategic applications and by a shift in thinking about the sources of nuclear threats and how they should be addressed, primarily, but not solely, in the United States. Recent scholarship has rightly identified a new set of challenges posed by the development of strategic non-nuclear weaponry (SNNW). But the full implications of this transformation in policy, technology and thinking for the global nuclear order as a whole have so far been underexplored. To remedy this, we look further ahead to the ways in which current trends, if taken to their logical conclusion, have the capacity to usher in a new nuclear era. We argue that in the years ahead, SNNW will increasingly shape the nuclear order, particularly in relation to questions of stability and risk. In the Third Nuclear Age, nuclear deployments, postures, balances, arms control, non-proliferation policy, and the prospects for disarmament, will all be shaped as much by developments in SNNW capabilities as by nuclear weapons. Consequently, we advocate for an urgent reassessment of the way nuclear order and nuclear risks are conceptualised as we confront the challenges of a Third Nuclear Age.
Influence of Late Holocene climate on Lake Eggers hydrology, McMurdo Sound
Authors: Chamberlain E.J. , Christ A.J. , Fulweiler R.W. 
Published: February 2021

AbstractIce-covered lakes in Antarctica preserve records of regional hydroclimate and harbour extreme ecosystems that may serve as terrestrial analogues for exobiotic environments. Here, we examine the impacts of hydroclimate and landscape on the formation history of Lake Eggers, a small ice-sealed lake, located in the coastal polar desert of McMurdo Sound, Antarctica (78°S). Using ground penetrating radar surveys and three lake ice cores we characterize the ice morphology and chemistry. Lake ice geochemistry indicates that Lake Eggers is fed primarily from local snowmelt that accreted onto the lake surface during runoff events. Radiocarbon ages of ice-encased algae suggest basal ice formed at least 735 ± 20 calibrated years before present (1215 C.E.). Persisting through the Late Holocene, Lake Eggers alternated between periods of ice accumulation and sublimation driven by regional climate variability in the western Ross Sea. For example, particulate organic matter displayed varying δ15N ratios with depth, corresponding to sea ice fluctuations in the western Ross Sea during the Late Holocene. These results suggest a strong climatic control on the hydrologic regime shifts shaping ice formation at Lake Eggers.
New Type of Short High‐Frequency VLF Patches (“VLF Birds”) Above 4–5 kHz
Authors: Manninen Jyrki , Kleimenova Natalia , Turunen Tauno , Nikitenko Alexander , Gromova Liudmila , Fedorenko Yury 
Published: February 2021

AbstractThe new type of daytime natural very low frequency (VLF) whistler mode emissions of the magnetospheric origin was found in the VLF observations at Kannuslehto station (L ∼ 5.5) in Northern Finland. The events occurred at the frequencies above 4–5 kHz even up to 15 kHz. These emissions have never been observed earlier in the spectrograms because they were hidden by strong impulsive atmospherics (sferics) in the same frequency range originating in lightning discharges. After filtering out the sferics, we surprisingly discovered completely new types of high frequency right‐hand polarized peculiar VLF emissions with various unusual dynamic spectra. These new VLF emissions typically occur as a sequence of a number of short (∼1–3 min) burst‐like structures or single short patches with the total duration up to a few hours. The spectral peculiarities of several long‐lasting VLF events as well as individual short VLF patches are discussed. The dynamic spectra of these new VLF patches raise the question of the temporal and spatial details of the wave‐particle interactions in the magnetospheric plasma. These emissions are observed only under quiet or weakly disturbed space weather conditions, but during small negative values of the Dst index, indicating the presence of a certain excess of the radiation belt electrons. Note, these high frequency VLF patches are observed at the frequencies much higher than the half of the equatorial electron gyrofrequency which is equal to ∼2.7 kHz at L ∼ 5.5. It seems that these emissions are generated deep in the magnetosphere, but the detailed nature, generation region, and propagation behavior of these newly discovered VLF emissions remain unknown. An appearance of high frequency VLF patches could be an indirect indicator of a local enhancement of electron fluxes in the radiation belt that are not directly measured and may occur even in the absence of visible ground‐based geomagnetic disturbances. Further researches may shed new light on wave‐particle interactions occurring in the Earth's radiation belts.
Comparison of Flexible and Rigid Vegetation Induced Shear Layers in Partly Vegetated Channels
Authors: Caroppi Gerardo , Västilä Kaisa , Gualtieri Paola , Järvelä Juha , Giugni Maurizio , Rowiński Paweł M. 
Published: February 2021

AbstractNatural riparian vegetation generally presents a complex hydrodynamic behavior governed by plant morphology and flexibility. By contrast, hydrodynamic processes in partly vegetated channels are conventionally simulated by using simplified model vegetation, such as arrays of rigid cylinders. The aim of this study is to investigate the impacts of embedding natural plant features in the experimental simulation of flow in partly vegetated channels. Unique comparative experiments were carried out with both reconfiguring vegetation made of natural‐like shrubs and grasses, and with rigid cylinders. While the lateral distributions of flow properties presented a high similarity governed by the shear layer differential velocity ratio, the bulk vegetative drag, and the presence of large‐scale vortices, the flexibility‐induced mechanisms of natural‐like vegetation markedly affected the flow at the interface. Differences in plant morphology and spacing, and the dynamic motion of flexible foliated plants induced deeper vortex penetration into the vegetation. The normalized shear penetration was 6–10 times greater than observed for rigid cylinders, resulting in wider zones significantly exchanging momentum with the adjacent open water. The efficiency of lateral momentum transport for flexible foliated vegetation was up to 40% greater than the corresponding rigid cylinder case. Overall, the results indicated that improving the representativeness of model vegetation is a critical step toward the accurate simulation of hydrodynamic and transport processes in natural settings.
The molecular conformation of silk fibroin regulates osteogenic cell behavior by modulating the stability of the adsorbed protein-material interface
Authors: Long Yanlin , Cheng Xian , Jansen John A. , Leeuwenburgh Sander G. C. , Mao Jing , Yang Fang , Chen Lili 
Published: February 2021

AbstractSilk fibroin (SF) can be used to construct various stiff material interfaces to support bone formation. An essential preparatory step is to partially transform SF molecules from random coils to β-sheets to render the material water insoluble. However, the influence of the SF conformation on osteogenic cell behavior at the material interface remains unknown. Herein, three stiff SF substrates were prepared by varying the β-sheet content (high, medium, and low). The substrates had a comparable chemical composition, surface topography, and wettability. When adsorbed fibronectin was used as a model cellular adhesive protein, the stability of the adsorbed protein-material interface, in terms of the surface stability of the SF substrates and the accompanying fibronectin detachment resistance, increased with the increasing β-sheet content of the SF substrates. Furthermore, (i) larger areas of cytoskeleton-associated focal adhesions, (ii) higher orders of cytoskeletal organization and (iii) more elongated cell spreading were observed for bone marrow-derived mesenchymal stromal cells (BMSCs) cultured on SF substrates with high vs. low β-sheet contents, along with enhanced nuclear translocation and activation of YAP/TAZ and RUNX2. Consequently, osteogenic differentiation of BMSCs was stimulated on high β-sheet substrates. These results indicated that the β-sheet content influences osteogenic differentiation of BMSCs on SF materials in vitro by modulating the stability of the adsorbed protein-material interface, which proceeds via protein-focal adhesion-cytoskeleton links and subsequent intracellular mechanotransduction. Our findings emphasize the role of the stability of the adsorbed protein-material interface in cellular mechanotransduction and the perception of stiff SF substrates with different β-sheet contents, which should not be overlooked when engineering stiff biomaterials.
Development and validation for research assessment of Oncotype DX® Breast Recurrence Score, EndoPredict® and Prosigna®
Authors: Buus Richard , Szijgyarto Zsolt , Schuster Eugene F. , Xiao Hui , Haynes Ben P. , Sestak Ivana , Cuzick Jack , Paré Laia , Seguí Elia , Chic Nuria , Prat Aleix , Dowsett Mitch , Cheang Maggie Chon U. 
Published: February 2021

AbstractMulti-gene prognostic signatures including the Oncotype® DX Recurrence Score (RS), EndoPredict® (EP) and Prosigna® (Risk Of Recurrence, ROR) are widely used to predict the likelihood of distant recurrence in patients with oestrogen-receptor-positive (ER+), HER2-negative breast cancer. Here, we describe the development and validation of methods to recapitulate RS, EP and ROR scores from NanoString expression data. RNA was available from 107 tumours from postmenopausal women with early-stage, ER+, HER2− breast cancer from the translational Arimidex, Tamoxifen, Alone or in Combination study (TransATAC) where previously these signatures had been assessed with commercial methodology. Gene expression was measured using NanoString nCounter. For RS and EP, conversion factors to adjust for cross-platform variation were estimated using linear regression. For ROR, the steps to perform subgroup-specific normalisation of the gene expression data and calibration factors to calculate the 46-gene ROR score were assessed and verified. Training with bootstrapping (n = 59) was followed by validation (n = 48) using adjusted, research use only (RUO) NanoString-based algorithms. In the validation set, there was excellent concordance between the RUO scores and their commercial counterparts (rc(RS) = 0.96, 95% CI 0.93–0.97 with level of agreement (LoA) of −7.69 to 8.12; rc(EP) = 0.97, 95% CI 0.96–0.98 with LoA of −0.64 to 1.26 and rc(ROR) = 0.97 (95% CI 0.94–0.98) with LoA of −8.65 to 10.54). There was also a strong agreement in risk stratification: (RS: κ = 0.86, p < 0.0001; EP: κ = 0.87, p < 0.0001; ROR: κ = 0.92, p < 0.001). In conclusion, the calibrated algorithms recapitulate the commercial RS and EP scores on individual biopsies and ROR scores on samples based on subgroup-centreing method using NanoString expression data.