bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlled synthesis of unsubstituted high molecular weight poly(para-phenylene) via Suzuki polycondensation-thermal aromatization methodology
Authors: Pavlović Dražen , Cohen Shmuel
Published: March 2020

Palladium-catalysed Suzuki polycondensation in conjunction with thermal aromatization of cis- and trans-prepolymer precursors (1a and 1b) has been applied in polyphenylene chemistry, giving access to well-defined high-molecular weight PPP.
Synthesis of side-chain regioregular and main-chain alternating poly(bichalcogenophene)s and an ABC-type periodic poly(terchalcogenophene)
Authors: Liu Huai-Hsuan , Liang Wei-Wei , Lai Yu-Ying , Su Yen-Chen , Yang Hau-Ren , Cheng Kuang-Yi , Huang Sheng-Cih , Cheng Yen-Ju
Published: March 2020

Three unsymmetrical diiodobichalcogenophenes SSeI2, STeI2, and SeTeI2 and a diiodoterchalcogenophene SSeTeI2 were prepared to synthesize a new class of polychalcogenophenes with precisely controlled sequences by catalyst-transfer polycondensation.
Two-dimensional metal–organic framework nanosheets: synthetic methodologies and electrocatalytic applications
Authors: Jiang Qinyuan , Zhou Chenhui , Meng Haibing , Han Ying , Shi Xiaofei , Zhan Chenhao , Zhang Rufan
Published: March 2020

This review gives a systematic discussion on the synthetic methodologies of 2D MOF-based materials for electrocatalysis applications.
Ultrasensitive Fe3+ion detection based on carbon quantum dot-functionalized solution-gated graphene transistors
Authors: Fan Qin , Li Jinhua , Wang Jianying , Yang Zilu , Shen Tao , Guo Yizhong , Wang Lihua , Irshad Muhammad Sultan , Mei Tao , Wang Xianbao
Published: March 2020

Carbon quantum dots are successfully integrated into a solution gated graphene transistor-based sensor for ultrasensitive Fe3+ion detection.
Early ageing detection of battery cells in battery management system
Authors: Farjah A. , Ghanbari T.
Published: March 2020

In this Letter, a battery state of health monitoring technique suitable for battery management systems is presented. This method analyses switching and battery transitions in the battery management system topologies to distinguish any early degraded battery cell in the battery strings. The proposed technique processes the voltage of the system, captured by an already employed sensor during the transition of the states. To verify the performance of the proposed technique, some experiments have been carried out on a typical charge balancing circuit.
Observer‐based stability of switched system under jamming attack and random packet loss
Authors: Lian Jie , Huang Xi , Han Yuchen
Published: March 2020

This study investigates the cyber‐security control problem of a networked switched system. Firstly, a joint probabilistic model is utilised to characterise the communication failure caused by the jamming attack and random packet loss. Then the attention is focused on designing an observer based controller that can generate the control input using the last successfully received system output. After that, with the average dwell time scheme, sufficient conditions are derived to ensure the almost sure asymptotical stability of the overall‐system with stable and unstable subsystems. In addition, an approach is developed to obtain the feasible solution of state feedback and observer gains. Finally, a simulation example implies the effectiveness of the authors' methods.
Stabilisation of switched linear systems under denial of service
Authors: Qu Hanqing , Zhao Jun
Published: March 2020

The authors consider the stabilising problem for switched linear systems subject to denial‐of‐service (DoS) attacks that block communications on the network. Using the periodic sampled‐data control, the authors first research the switched systems where no DoS attacks occur, and a class of switching signals satisfying the average dwell time is presented to stabilise the switched systems in which the authors take asynchronous switching into consideration. Then, using the presented switching signals, a sufficient condition with respect to DoS attack duration and frequency is given to keep switched systems stable under DoS attacks. The condition reflects the relation between attack rate and system stability. The authors also analyse the qualitative relation between average dwell time and system robustness against attacks. Compared with non‐switched systems, the analysis of switched systems under DoS attacks is more challenging. They finally give a numerical example to show the validity of the result.
Adaptive tracking control for a class of stochastic non‐linear systems with input saturation constraint using multi‐dimensional Taylor network
Authors: Han Yu‐Qun
Published: March 2020

The randomness and input saturation increase computational complexity and impede the tracking performance of stochastic non‐linear systems, therefore, it is necessary to build a simple but effective controller. Based on this, a multi‐dimensional Taylor network (MTN) is first applied to a class of stochastic non‐linear systems with input saturation constraint in this study. Aiming to solve the tracking control problem, a novel MTN‐based controller is proposed via backstepping, and the proposed control scheme has some advantages such as simple structure, good real‐time performance and easy realisation. With the help of the hyperbolic tangent function approximating the symmetric saturation non‐linearity, an adaptive MTN tracking control scheme is constructively designed via backstepping technique. The simulation results are given to illustrate the validity and accuracy of the model of the proposed approach.
Distributed formation control of the special Euclidean group SE(2) via global orientation control
Authors: Lee Jae‐Gyeong , Trinh Minh Hoang , Ahn Hyo‐Sung , Lee Byung‐Hun
Published: March 2020

The authors propose fully distributed strategies for multi‐agent formation control of the two‐dimensional special Euclidean group. To control the rotated local reference frames, they firstly estimate the orientation angle of each agent with regard to a global reference frame. By using only local measurements, the orientation angle is estimated in a distributed way. The estimated orientation is, then, exploited to control each agent's orientation. Each agent's orientation converges to the prescribed desired orientation. Finally, a distributed formation control strategy based on displacement measurement is proposed to achieve the desired formation shape of the two‐dimensional special Euclidean group. Under the proposed strategy, the authors ensure that the formation shape including position and orientation exponentially converges to the desired formation shape. Moreover, the formation shape is invariant to a translation and a rotation compared with the desired formation shape.
Robust tracking control of quadrotor based on flatness and active disturbance rejection control
Authors: Abadi Amine , Amraoui Adnen El , Mekki Hassen , Ramdani Nacim
Published: March 2020

This study proposes a robust tracking controller for an underactuated quadrotor model based on the flatness theory and active disturbance rejection control (ADRC). Exploiting the differential flatness characteristic, it is demonstrated that a non‐linear quadrotor system can be changed into a linear canonical form, where it is easier to create a state feedback controller that ensures accurate trajectory tracking. In order to improve the tracking performance of the quadrotor, other factors are considered in the conception of the state feedback controller consisting in the estimation of the un‐measurable state variables in a canonical (Brunovsky) form and in the elimination of external perturbations and modelling uncertainties affecting the quadrotor system. To deal with this problem, first, an extended state observer (ESO) is designed to estimate a system state and an extended state known as lumped uncertainties. The latter represents the total effects of uncertain parameters, the neglected part of non‐linearity and the external disturbances. Second, based on the ESO result, an additional term is integrated into the feedback controller to eliminate the lumped disturbance effects and to ensure the stability of the closed loop. Simulation results are introduced to prove the benefits of associating the ADRC approach with flatness control.
Introducing a novel FSPM motor with double rotor and toroidal windings
Authors: Jafarboland Mehrdad , Sargazi Mostafa M.
Published: March 2020

In this study, a new flux‐switching permanent‐magnet (FSPM) motor with two rotors and toroidal coil are introduced. First, the proposed FSPM (PFSPM) motor structure and performance principles are presented. Then, the performance parameters of the PFSPM motor, including flux linkage, back‐electromotive force, air‐gap flux distribution, inductance, eddy current loss, cogging torque and the output electromagnetic torque are compared with a conventional FSPM motor based on finite‐element analysis. Then, the effect of the angle between the two‐rotor poles on the performance parameters of the PFSPM motor is indicated. Finally, the PFSPM motor model is manufactured and the results of the finite‐element test are compared with the results of the experimental test and the accuracy of the finite‐element model is confirmed.
DC‐biased sinusoidal excited switched reluctance motor
Authors: Kuai Songyan , Yang Houqing , Li Xuanxi , Chen FuHao
Published: March 2020

In this study, a DC‐biased sinusoidal excited control method is proposed for a traditional four‐phase switched reluctance motor (SRM). Based on the proposed method, the torque ripple is smaller than that of traditional square excitation. First, the mathematical model of four‐phase SRM with DC‐biased sinusoidal excitation in dq‐axis rotating coordinate system is established and the instantaneous torque is analysed. It is found that the torque is proportional to q‐axis current and does not contain reluctance torque component with DC‐biased sinusoidal excitation for four‐phase SRM. Then the current control methods for torque component and magnetic field component are studied. The torque component is controlled by the sinusoidal pulse‐width modulation (PWM) method, and the magnetic field component is controlled by the current hysteresis tracking method. Finally, the proposed method is verified by finite element simulation and experiment results. Compared with the square wave excitation, the torque ripple is reduced by about 40%.
Segmentation of the pulmonary nodule and the attached vessels in the CT scan of the chest using morphological features and topological skeleton of the nodule
Authors: Tavakoli Mahsa Bank , Orooji Mahdi , Teimouri Mehdi , Shahabifar Ramita
Published: March 2020

Nowadays, the proficiency of Computer‐Aided Diagnosis systems for early diagnosis of malignant nodules in baseline Computed Tomography (CT) scan of chest crucially depends on the authenticity of the segmented nodule. In this study, the authors introduce a new morphological feature called solidity radius (SR). They then employ this feature in the new segmentation framework for the automatic segmentation of nodule and the attached vessels around the seed point on the nodule, delineated by an expert. In the framework, they extract the SR and the curvature features and employ them to determine the candidate pixels of the nodule. They then use the convex‐hull image of the candidate pixels to surround the nodule area. Afterward, using the region growing on the Hessian‐based vesselness enhancement map, the attached vessels are labelled. Finally, they apply the traditional solidity feature of the segmented nodule and the pattern of the related skeleton to prune the false positive pieces. They validate the introduced approach on two datasets, including 56 and 481 CTs (containing 1205 nodules). They show the proficiency of their SR‐based approach compared to the state‐of‐the‐art methods with average Dice Similarity Coefficients of 77.98 and 77.47% for the two datasets, respectively.
Analogue predistortion lineariser control schemes for ultra‐broadband signal transmission in 5G transmitters
Authors: Gumber Karan , Rawat Meenakshi
Published: March 2020

Analogue predistorter (APD) has gained a new significance due to the need for high bandwidth in the fifth generation (5G) communication. As predistorted signal is generated in the analogue domain, it is free from data converter bandwidth limitation and presents an attractive linearisation solution for power amplifier (PA) in the 5G base station. Furthermore, it also finds its application in the multicarrier repeater system for long‐distance communication, where the baseband information is not readily available. However, the performance of the conventional APD is dependent on the appropriate control of gain and phase of the predistorted signal. The state‐of‐the‐art work in analogue linearisation solutions mostly utilises vector multiplier for such a control. This work points out the limitations of such a scheme and proposes a novel control scheme (CS) that is capable of extracting better benefits of the APD. An experimental validation is carried out by linearising 10 W HMC8500 broadband GaN PA, excited by a eight‐component carrier 160 MHz ultra‐broadband long‐term evolution signal. The proposed Type‐II CS delivers an adjacent channel power ratio of −45.05 dBc with an improvement of 18 dB, which is 4 dB better than Type‐I CS.
Dynamic positioning of ships based on robust fuzzy observer
Authors: Ngongi Werneld , Du Jialu , Massami Erick , Chang Wen‐Jer , Kassembe Eliamin
Published: March 2020

In this study, the robust fuzzy observer‐based control scheme for the dynamic positioning of marine vessels is presented. The proposed controller assumes that the environmental disturbances are unknown but bounded with known upper limit. First, the authors apply the Takagi–Sugeno fuzzy model to approximate the ship model. Using formulated fuzzy model, the robust fuzzy observer is developed to approximate the unknown states. Then, by employing optimal disturbance attenuation technique, the effects of the environmental disturbances can be attenuated to least value. Finally, the linear matrix inequality technique is hired for solving the optimal robust problem. Model ship is used for simulation, and results are given to prove the validity of the presented controller.
The effect of the environment-dependent IMF on the formation and metallicities of stars over the cosmic history
Authors: Chruślińska M. , Jeřábková T. , Nelemans G. , Yan Z.
Published: March 2020

Recent observational and theoretical studies indicate that the stellar initial mass function (IMF) varies systematically with the environment (star formation rate – SFR, metallicity). Although the exact dependence of the IMF on those properties is likely to change with improving observational constraints, the reported trend in the shape of the IMF appears robust. We present the first study aiming to evaluate the effect of the IMF variations on the measured cosmic SFR density (SFRD) as a function of metallicity and redshift,fSFR(Z,z). We also study the expected number and metallicity of white dwarf, neutron star, and black hole progenitors under different IMF assumptions. Applying the empirically driven IMF variations described by the integrated galactic IMF (IGIMF) theory, we revisefSFR(Z,z) obtained in our previous study that assumed a universal IMF. We find a lower SFRD at high redshifts and a higher fraction of metal-poor stars being formed than previously determined. In the local Universe, our calculation applying the IGIMF theory suggests more white dwarf and neutron star progenitors in comparison with the universal IMF scenario, while the number of black hole progenitors remains unaffected.
Reproducible Software Environment: a tool enabling computational reproducibility in geospace sciences and facilitating collaboration
Authors: Bhatt Asti , Valentic Todd , Reimer Ashton , Lamarche Leslie , Reyes Pablo , Cosgrove Russell
Published: March 2020

The Reproducible Software Environment (Resen) is an open-source software tool enabling computationally reproducible scientific results in the geospace science community. Resen was developed as part of a larger project called the Integrated Geoscience Observatory (InGeO), which aims to help geospace researchers bring together diverse datasets from disparate instruments and data repositories, with software tools contributed by instrument providers and community members. The main goals of InGeO are to remove barriers in accessing, processing, and visualizing geospatially resolved data from multiple sources using methodologies and tools that are reproducible. The architecture of Resen combines two mainstream open source software tools, Docker and JupyterHub, to produce a software environment that not only facilitates computationally reproducible research results, but also facilitates effective collaboration among researchers. In this technical paper, we discuss some challenges for performing reproducible science and a potential solution via Resen, which is demonstrated using a case study of a geospace event. Finally we discuss how the usage of mainstream, open-source technologies seems to provide a sustainable path towards enabling reproducible science compared to proprietary and closed-source software.
Killer whale presence drives bowhead whale selection for sea ice in Arctic seascapes of fear
Authors: Matthews Cory J. D. , Breed Greg A. , LeBlanc Bernard , Ferguson Steven H.
Published: March 2020

The effects of predator intimidation on habitat use and behavior of prey species are rarely quantified for large marine vertebrates over ecologically relevant scales. Using state space movement models followed by a series of step selection functions, we analyzed movement data of concurrently tracked prey, bowhead whales (
Balaena mysticetus
;
n
= 7), and predator, killer whales (
Orcinus orca; n
= 3), in a large (63,000 km
2
), partially ice-covered gulf in the Canadian Arctic. Our analysis revealed pronounced predator-mediated shifts in prey habitat use and behavior over much larger spatiotemporal scales than previously documented in any marine or terrestrial ecosystem. The striking shift from use of open water (predator-free) to dense sea ice and shorelines (predators present) was exhibited gulf-wide by all tracked bowheads during the entire 3-wk period killer whales were present, constituting a nonconsumptive effect (NCE) with unknown energetic or fitness costs. Sea ice is considered quintessential habitat for bowhead whales, and ice-covered areas have frequently been interpreted as preferred bowhead foraging habitat in analyses that have not assessed predator effects. Given the NCEs of apex predators demonstrated here, however, unbiased assessment of habitat use and distribution of bowhead whales and many marine species may not be possible without explicitly incorporating spatiotemporal distribution of predation risk. The apparent use of sea ice as a predator refuge also has implications for how bowhead whales, and likely other ice-associated Arctic marine mammals, will cope with changes in Arctic sea ice dynamics as historically ice-covered areas become increasingly ice-free during summer.
CD300f immunoreceptor is associated with major depressive disorder and decreased microglial metabolic fitness
Authors: Lago Natalia , Kaufmann Fernanda N. , Negro-Demontel María Luciana , Alí-Ruiz Daniela , Ghisleni Gabriele , Rego Natalia , Arcas-García Andrea , Vitureira Nathalia , Jansen Karen , Souza Luciano M. , Silva Ricardo A. , Lara Diogo R. , Pannunzio Bruno , Abin-Carriquiry Juan Andrés , Amo-Aparicio Jesús , Martin-Otal Celia , Naya Hugo , McGavern Dorian B. , Sayós Joan , López-Vales Rubèn , Kaster Manuella P. , Peluffo Hugo
Published: March 2020

A role for microglia in neuropsychiatric diseases, including major depressive disorder (MDD), has been postulated. Regulation of microglial phenotype by immune receptors has become a central topic in many neurological conditions. We explored preclinical and clinical evidence for the role of the CD300f immune receptor in the fine regulation of microglial phenotype and its contribution to MDD. We found that a prevalent nonsynonymous single-nucleotide polymorphism (C/T, rs2034310) of the human CD300f receptor cytoplasmic tail inhibits the protein kinase C phosphorylation of a threonine and is associated with protection against MDD, mainly in women. Interestingly, CD300f
−/−
mice displayed several characteristic MDD traits such as augmented microglial numbers, increased interleukin 6 and interleukin 1 receptor antagonist messenger RNA, alterations in synaptic strength, and noradrenaline-dependent and persistent depressive-like and anhedonic behaviors in females. This behavioral phenotype could be potentiated inducing the lipopolysaccharide depression model. RNA sequencing and biochemical studies revealed an association with impaired microglial metabolic fitness. In conclusion, we report a clear association that links the function of the CD300f immune receptor with MDD in humans, depressive-like and anhedonic behaviors in female mice, and altered microglial metabolic reprogramming.
Sitting, squatting, and the evolutionary biology of human inactivity
Authors: Raichlen David A. , Pontzer Herman , Zderic Theodore W. , Harris Jacob A. , Mabulla Audax Z. P. , Hamilton Marc T. , Wood Brian M.
Published: March 2020

Significance

Inactivity is a growing public health risk in industrialized societies, leading some to suggest that our bodies did not evolve to be sedentary. Here, we show that, in a group of hunter-gatherers, time spent sedentary is similar to that found in industrialized populations. However, sedentary time in hunter-gatherers is often spent in postures like squatting that lead to higher levels of muscle activity than chair sitting. Thus, we suggest human physiology likely evolved in a context that included substantial inactivity, but increased muscle activity during sedentary time, suggesting an inactivity mismatch with the more common chair-sitting postures found in contemporary urban populations.
Common power laws for cities and spatial fractal structures
Authors: Mori Tomoya , Smith Tony E. , Hsu Wen-Tai
Published: March 2020

Significance

Socioeconomic attributes of cities (e.g., wages, education, industrial diversity, and crime) exhibit strong correlations with city size, as measured by population. It has thus been a major research objective to characterize and explain city-size distributions. Whereas city-size distributions are known to exhibit power laws at the country level, we find that they exhibit strikingly similar power laws when examined along a spatial hierarchy of regions within a country. Such a high degree of similarity could not be obtained if city sizes were generated by a random (growth) process. The fact that this regularity emerges along spatial dimensions in a recursive manner suggests the existence of spatial fractal structures. However, such estimated common power laws differ markedly across countries.
Delayed negative effects of prosocial spending on happiness
Authors: Falk Armin , Graeber Thomas
Published: March 2020

Does prosocial behavior promote happiness? We test this longstanding hypothesis in a behavioral experiment that extends the scope of previous research. In our Saving a Life paradigm, every participant either saved one human life in expectation by triggering a targeted donation of 350 euros or received an amount of 100 euros. Using a choice paradigm between two binary lotteries with different chances of saving a life, we observed subjects’ intentions at the same time as creating random variation in prosocial outcomes. We repeatedly measured happiness at various delays. Our data weakly replicate the positive effect identified in previous research but only for the very short run. One month later, the sign of the effect reversed, and prosocial behavior led to significantly lower happiness than obtaining the money. Notably, even those subjects who chose prosocially were ultimately happier if they ended up getting the money for themselves. Our findings revealed a more nuanced causal relationship than previously suggested, providing an explanation for the apparent absence of universal prosocial behavior.
Potent CRISPR-Cas9 inhibitors fromStaphylococcusgenomes
Authors: Watters Kyle E. , Shivram Haridha , Fellmann Christof , Lew Rachel J. , McMahon Blake , Doudna Jennifer A.
Published: March 2020

Significance

Many mobile genetic elements contain anti-CRISPRs (Acrs) to evade host CRISPR defenses. Acrs have been discovered that inhibit therapeutically relevant CRISPR-Cas gene editors such as Cas12 and Cas9, including many inhibitors forStreptococcus pyogenesCas9 (SpyCas9). However, there are few inhibitors known for the Cas9 fromStaphylococcus aureus(SauCas9), which is both highly active in human cells and easier to deliver than SpyCas9 due to its smaller size. In this work, we search withinStaphylococcusgenomes for Acrs able to inhibit SauCas9. We discover three Acrs (AcrIIA13, AcrIIA14, and AcrIIA15) and demonstrate all three are able to inhibit CRISPR-Cas9 gene editing. Our findings highlight the utility of our Acr search method for finding Acrs against specific Cas nucleases.
The Tol-Pal system is required for peptidoglycan-cleaving enzymes to complete bacterial cell division
Authors: Yakhnina Anastasiya A. , Bernhardt Thomas G.
Published: March 2020

Significance

The outer membrane of gram-negative bacteria presents a formidable barrier for the entry of antibiotics and is a significant contributor to the intrinsic drug resistance of these organisms. The highly conserved Tol-Pal complex has long been known to be required for the proper biogenesis of this surface layer, with its main function commonly believed to be promoting outer membrane constriction during cell division. In this report, we show that the machinery is needed to promote the cleavage of cell wall glycans at the division site to promote daughter cell separation. Thus, the Tol-Pal system may play multiple roles during cell division to ensure that outer membrane invagination and cell wall processing are properly coordinated.
Optofluidic control of rodent learning using cloaked caged glutamate
Authors: Durand-de Cuttoli Romain , Chauhan Pradeep S. , Pétriz Reyes Adriana , Faure Philippe , Mourot Alexandre , Ellis-Davies Graham C. R.
Published: March 2020

Glutamate is the major excitatory neurotransmitter in the brain, and photochemical release of glutamate (or uncaging) is a chemical technique widely used by biologists to interrogate its physiology. A basic prerequisite of these optical probes is bio-inertness before photolysis. However, all caged glutamates are known to have strong antagonism toward receptors of γ-aminobutyric acid, the major inhibitory transmitter. We have developed a caged glutamate probe that is inert toward these receptors at concentrations that are effective for photolysis with violet light. Pharmacological tests in vitro revealed that attachment of a fifth-generation (G5) dendrimer (i.e., cloaking) to the widely used 4-methoxy-7-nitro-indolinyl(MNI)-Glu probe prevented such off-target effects while not changing the photochemical properties of MNI-Glu significantly. G5-MNI-Glu was used with optofluidic delivery to stimulate dopamine neurons of the ventral tegmental area of freely moving mice in a conditioned place-preference protocol so as to mediate Pavlovian conditioning.
Ostrich eggshell bead strontium isotopes reveal persistent macroscale social networking across late Quaternary southern Africa
Authors: Stewart Brian A. , Zhao Yuchao , Mitchell Peter J. , Dewar Genevieve , Gleason James D. , Blum Joel D.
Published: March 2020

Significance

Hunter-gatherers like the Ju/’hoãnsi (!Kung) San use exchange networks to dampen subsistence and reproductive risks, but almost nothing is known of how, when, and why such practices emerged. Strontium isotope analysis of one preferred San exchange item, ostrich eggshell beads, from highland Lesotho shows that since the late Middle Stone Age ∼33 ka, such networks connected ecologically complementary regions over minimal distances of several hundred kilometers. Rapidly changing environmental conditions during Marine Isotope Stage 3 (∼59 to 25 ka) likely placed a premium on developing effective means of mitigating subsistence and demographic risks, with ostrich eggshell beads providing a uniform medium of personal decoration and exchange highly suitable for binding together extended open social networks.
Longitudinal dynamics of the human B cell response to the yellow fever 17D vaccine
Authors: Wec Anna Z. , Haslwanter Denise , Abdiche Yasmina N. , Shehata Laila , Pedreño-Lopez Nuria , Moyer Crystal L. , Bornholdt Zachary A. , Lilov Asparouh , Nett Juergen H. , Jangra Rohit K. , Brown Michael , Watkins David I. , Ahlm Clas , Forsell Mattias N. , Rey Félix A. , Barba-Spaeth Giovanna , Chandran Kartik , Walker Laura M.
Published: March 2020

A comprehensive understanding of the development and evolution of human B cell responses induced by pathogen exposure will facilitate the design of next-generation vaccines. Here, we utilized a high-throughput single B cell cloning technology to longitudinally track the human B cell response to the yellow fever virus 17D (YFV-17D) vaccine. The early memory B cell (MBC) response was mediated by both classical immunoglobulin M (IgM) (IgM
+
CD27
+
) and switched immunoglobulin (swIg
+
) MBC populations; however, classical IgM MBCs waned rapidly, whereas swIg
+
and atypical IgM
+
and IgD
+
MBCs were stable over time. Affinity maturation continued for 6 to 9 mo following vaccination, providing evidence for the persistence of germinal center activity long after the period of active viral replication in peripheral blood. Finally, a substantial fraction of the neutralizing antibody response was mediated by public clones that recognize a fusion loop-proximal antigenic site within domain II of the viral envelope glycoprotein. Overall, our findings provide a framework for understanding the dynamics and complexity of human B cell responses elicited by infection and vaccination.
An MXD1-derived repressor peptide identifies noncoding mediators of MYC-driven cell proliferation
Authors: Raffeiner Philipp , Hart Jonathan R. , García-Caballero Daniel , Bar-Peled Liron , Weinberg Marc S. , Vogt Peter K.
Published: March 2020

MYC controls the transcription of large numbers of long noncoding RNAs (lncRNAs). Since MYC is a ubiquitous oncoprotein, some of these lncRNAs probably play a significant role in cancer. We applied CRISPR interference (CRISPRi) to the identification of MYC-regulated lncRNAs that are required for MYC-driven cell proliferation in the P493-6 and RAMOS human lymphoid cell lines. We identified 320 noncoding loci that play positive roles in cell growth. Transcriptional repression of any one of these lncRNAs reduces the proliferative capacity of the cells. Selected hits were validated by RT-qPCR and in CRISPRi competition assays with individual GFP-expressing sgRNA constructs. We also showed binding of MYC to the promoter of two candidate genes by chromatin immunoprecipitation. In the course of our studies, we discovered that the repressor domain SID (SIN3-interacting domain) derived from the MXD1 protein is highly effective in P493-6 and RAMOS cells in terms of the number of guides depleted in library screening and the extent of the induced transcriptional repression. In the cell lines used, SID is superior to the KRAB repressor domain, which serves routinely as a transcriptional repressor domain in CRISPRi. The SID transcriptional repressor domain is effective as a fusion to the MS2 aptamer binding protein MCP, allowing the construction of a doxycycline-regulatable CRISPRi system that allows controlled repression of targeted genes and will facilitate the functional analysis of growth-promoting lncRNAs.
Syntactic and Semantic Variation in Copular Sentences
Authors: Wilson Daniel J.
Published: March 2020

This book presents a novel account of syntactic and semantic variation in copular and existential sentences in Classical Hebrew. Like many languages, the system of Classical Hebrew copular sentences is quite complex, containing zero, pronominal, and verbal forms as well as eventive and inchoative semantics. Approaching this subject from the framework of Distributed Morphology provides an elegant and comprehensive explanation for both the syntactic and semantic variation in these sentences. This book also presents a theoretical model for analyzing copular sentences in other languages included related phenomena– such as pseudo-copulas. It is also a demonstration of what can be gained by applying modern linguistic analyses to dead languages. Citing and building off previous studies on this topic, this book will be of interest to those interested in the theoretical examination of copular and existential sentences and to those interested in Classical Hebrew more specifically.
On streams and lakes
Authors: Castor Theresa R.
Published: March 2020

This article advances the notion of metaventriloquism by bringing together the concepts of metacommunication and
ventriloquism (Cooren 2010). Metaventriloquism is when one makes claims regarding who or what
another is speaking behalf of. To explore the implications of metaventriloquism, a public hearing related to a community water controversy
is analyzed. The analysis illustrates how metaventriloquism may be used as a form of critique and operates retrospectively in claiming what
motivated another, and prospectively in claiming what another should do. The implications of metaventriloquism for the construction of
technological risks are also explored.
Is dialogue addictive?
Authors: Katambwe Jo M.
Published: March 2020

In this study, we shed some light on the thinking behind Facebook addiction. Since social network system are dialogical
communication tools, we carve out a space for a theoretical and methodological alternative to the research on social media addiction, as it
relates specifically to Facebook addiction. Based on several meta-evaluations and synthesis of extant empirical research, we uncover the two
most prominent functionalist approaches sustaining these empirical researches. Upon pointing to their epistemological, theoretical and
methodological limitations, we delve into dialogic approach and theory with a view to isolate how and what it is in a dialogic communication
that makes it addictive. Finally, we offer some theoretical and methodological alternatives from a dialogical perspective on how to study
Facebook addiction.
Beyond critical education for sustainable consumption
Authors: Chueh Ho-chia
Published: March 2020

This paper empirically supports environmental courses and activities based upon ‘parental altruism’ as an
effective environmental education in developing citizen’s pro-environmental values, attitudes, and behaviors. This is a case study
of the Homemaker’s Union Consumer Cooperation (HUCC), a prominent environmental consumer non-profit organization in Taiwan with
over 70000 members. Re-examining Paulo Freire’s critical dialogical pedagogy, this study uses Paul Stern’s three levels of value
orientation to investigate changes of HUCC members’ consumption behaviors. The courses and activities with parental-care are
efficiently received by members than those of critical knowledge with the environment in terms of developing pro-environmental
behaviors. Parental altruism is the key in changing consumer’s environmental values. This finding contributes to rethinking the
meaning of dialogue in environmental education.
Constructing others and dialoguewith them in the course of publiceducational meetings
Authors: Vasilyeva Alena L.
Published: March 2020

The study explores public educational meetings that aim to promote the Belarusian language and culture. In the
course of the meetings, those who do not have the same values and are not present during meetings are brought up into a
conversation. In other words, the voice of the others who are not part of the community gets involved in the dialogue.
Besides, some of the invited guests do not speak Belarusian and part of the audience is not necessarily interested in
learning Belarusian but rather attends these meetings to meet with those guests. In this respect, the study explores the
interactional resources the hosts and the attendees use to construct the dialogue with the other in their absence and in
their presence. It investigates who is considered to be the other and how the other is discursively constructed.
Phenomenological representation of mechanical spectroscopy of high damping MnCuNiFe alloy
Authors: Jiang Z. C. , Zhang S. B. , Tian Q. C. , Ji P. G. , Yin F. X.
Published: March 2020

MnCuNiFe damping alloy was prepared to characterise the dynamic mechanical behaviour under varied frequency by employing dynamic mechanical analyzer, optical microscopy and X-ray diffraction. The relationship of characteristic temperatures is disentangled by antiferromagnetic transition (AFT), the strain glass transition and reverse martensitic transformation. It is reported that although only f.c.c. (γ) phase exists in the alloy under solution state, twins are induced by AFT. The aged alloy shows an elevated damping capacity while the maximum internal friction decreases from 0.1 to 10 Hz and then increases to 150 Hz, demonstrating the system resonant frequency of about 10 Hz under the vibration mode of double cantilever beam.
Numerical study of the stress concentration factor in geometries of machine elements using Ansys® and Inventor®
Authors: Acevedo Román L F , Ardila J G , Valdes M , Castro A , López Quintero J G
Published: March 2020

In the present study the stress concentration factor by the finite element method in a round bar grooved axially under tension, a stepped flat plate subjected to bending and a stepped round bar subjected to torsion can be found. The stress concentration factor was obtained in the simulation laboratory through the commercial software ANSYS Workbench® version 19 and Autodesk Inventor 2016® and they were compared with the experimental curves enunciated in Peterson book, finding similarities up to 0.02% between simulation and experimental methods; and 0.3% between both pieces of software.
Estimation of the dispersion parameter in a population dynamics model of the coffee berry borer (Hypothenemus hampei)
Authors: Santander L D , Carmona P C , Acosta-Minoli C A
Published: March 2020

The main pest insect in coffee countries is the coffee berry borer(hypothenemus hampei), which impacts the coffee crops negatively. In this work, we estimate the dispersion parameter on a partial differential equation to model the population distribution in space of the coffee berry borer. To estimate the parameter, we use a technique based on the analytical resolution of the partial differential, data collected from a coffee farm to set up initial and boundary conditions, and the Bootstrap method. Results allow us to estimate the dispersion parameter with a coefficient of variation of 13%.
Instrument for selecting and evaluating suppliers in small and medium-sized metalworking enterprises in Cartagena, Colombia
Authors: L Álvarez V , C Gualdrón G , R Padrón C , L Sampayo C
Published: March 2020

The objective of this investigation is the definition of a practical tool that helps to improve the selection process and evaluation of suppliers in small and medium-sized metalworking enterprises in Cartagena city. For this purpose, a mixed approach methodology was used where data from 30 projects in the sector were mixed, together with related literature, to identify the most relevant factors. Once the information was reviewed, the multicriteria decision method known as the analytic hierarchy process was applied, where the experience, organizational structure, project resources, technical capacity, and previous performance were used as decision-making elements for the processes related to the selection and supplier’s evaluation.
Classification of pluviometric networks located in the region of Bogotá, Colombia using artificial neural networks
Authors: Garrido-Arévalo A R , Agudelo L M , Obregon N , Garrido V M
Published: March 2020

This work presents a methodology for the classification of pluviometric networks using artificial neural networks. For this, the network of stations registered in the Corporación Autónoma Regional de Cundinamarca, Colombia, was analyzed. The network studied consists of 182 stations for the measurement of precipitation and it has a historical series that goes, in some cases, from 1931 to the present. For the classification, three scenarios called types were proposed, in which the number of neurons in the output layer was varied. It was significant that when comparing the results of the different types, the permanence of certain features in the classification was found, indicating the validity of the classification.
Control of a charging station for electric vehicles
Authors: Martín Fernández L , Serra F , Angelo C De , Montoya O
Published: March 2020

A weighted average current control applied to a three-phase inductor-capacitor-inductor grid-connected battery charger for electric vehicles is presented in this paper. The proposed controller is based on a combination of the partial currents of the system (inverter and grid currents), which are feedback into the control loop. Therefore, by using this approach a reduction of the system order is achieved. The proposed controller allows a bidirectional control of the converter currents, thus allowing both, a controlled charge of the battery and the injection of the current with low distortion in the grid. Further, the implemented controller does not needs to measure the inverter currents. The control strategy is validated with simulation results.
Increasing driving range for electric vehicles at sub-zero temperatures by optimizing a hybrid storage configuration using supercapacitors
Authors: Dominguez-Jimenez J A , Campillo J
Published: March 2020

One of the main challenges electric vehicles manufacturers face is the perceived limited operational range of cars, commonly referred to as “range anxiety”. Furthermore, effective range in these vehicles is affected by multiple factors, including driving behavior, battery size, operating temperature, among others. Particularly, Lithium-based batteries the most used in the industry today, experience significant electrochemical changes when operating at sub-zero temperatures, which reduces their overall energy capacity. Furthermore, cycling operation under these conditions, could also severely reduce the batteries’ expected lifetime. This work uses a model-based approach to simulate a reduced current rate from lithium-based batteries, operating at sub-zero temperatures, during high-acceleration modes by including super-capacitors. By adding super-capacitors, the power supplied to the motors from the battery pack during short-time acceleration periods, can be reduced. This approach suggests that the effective range in Electric Vehicles increases by using an optimal hybrid energy storage system. Simulations were carried out to estimate the impact of subzero temperatures on the range of the vehicle. Results showed that the overall range increases with the addition of the the storage system. Furthermore, reduced current rates at sub-zero temperatures would also increase the battery pack’s expected lifetime. These results offer great insights for designing more efficient energy storage systems for electric vehicles.
Power flow solution in direct current grids using the linear conjugate gradient approach
Authors: Montoya O D , Escobar A F , Garrido V M
Published: March 2020

The Colombian power system is being modified by the large-scale integration of renewable energy resources and energy storage systems, in conjunction with the microgrid concept that originates the possibility of alternating and direct current grids or hybrid between them. Here, we propose a classical gradient conjugate method to solve linear algebraic equations without matrix inversions, to address the power flow problem in electrical direct current networks with constant power loads, to contribute with the paradigm of microgrids operated in direct current. This methodology can be applied to the power flow equations since the admittance matrix is positive definite and diagonal dominant which guarantees convergence of the power flow problems. Numerical simulations evidence the applicability of the gradient conjugate method to solve power flow problems in direct current networks with radial and mesh topologies. All the simulations are conducted in MATLAB software version 2017a licensed by the Universidad Tecnológica de Bolivar, Colombia.
Electrical transport through two-dimensional DNA nanostructure
Authors: Paez C J , Ospina R , Garcia-Castro A C
Published: March 2020

In this work, we numerically investigate the transport properties of a square lattice built from disordered deoxyribonucleic acid sequence. To do so, we used an effective tight-binding model to describe the electronic structure, while the current is obtained within a Green’s function framework. We show that the self-assembled DNA structures based-on the disordered sequences display currents, which, by increasing the size of the systems, quickly go to undetectable experimental current values.
Genetic algorithms for mathematical optimization
Authors: García J M , Acosta C A , Mesa M J
Published: March 2020

The inability to find the solution in engineering problems has led to a large part of the scientific community developing indirect and alternative techniques to find optimization problem-solving. Genetic algorithms are looking for models based on the natural and genetic selection process, which optimizes a population or set of possible solutions to deliver one that is optimal or at least very close to it in the sense of a fitting function. In this work, we derive and evaluate a method based on genetic algorithms to find the relative maximum of differentiable functions that are difficult to find by analytical methods. We build a library in Python that includes different components from genetic algorithms. The test problems include finding the maximum or minimum of functions in one and two dimensions.
Aerodynamics and flow pattern performance evaluation of off road vehicle for various velocity range and angle of incidence
Authors: Muruga Lal Jeyan JV , Nair Kavya S , Nair Krishna S
Published: March 2020

It is complex to amplify the significance of flow visualization. This is factual whether the methodology is strictly theoretical, primarily experimental, primarily computational or some combination as is always the most effective. The ability to see flow patterns on and around the device under investigation often gives insight into a solution to an aerodynamic problem. The reasonable mental image of a flow about a body is almost necessary for a researcher to have a useful understanding of an aerodynamic or hydrodynamic problem. We researcher and aerodynamicist believe possibilities of some significant difference in results obtained by computation and mental image and the experimental evidences resolve the uncertainty. In our research primitive variables that describe the flow and qualities are found to be use full in flow visualization phenomena. We resolve this with the concept of path line, stream line, streak line and time line approaches. A selective off road vehicle scaled model is tested by considering all the parameters. A low speed wind tunnel test facility with a calibrated test section size of 200 X200mm, low flow angularity providing acceptable laminar level and smoke tunnel facility is used for experimentations. The scale downed model is rationed with an allowable blockage factor not more than 10% is tested to a velocity range of 10m/s–50 m/s. Entire study and experiments on this Off-Road vehicle aerodynamics bounces adequate results. This experimental results and solutions will be useful for future young researchers in the field of off road vehicle design Aerodynamic analysis, more over this results gave a conceptual study for the person who drives the vehicle about the maximum occurrences, maximum possible drag and side slips over the vehicle.