bluuebunny/crossref_metadata_2025 huggingface dataset:
Lasing up to 380 K in a sublimated GaN nanowire
Authors: Sergent S. , Damilano B. , Vézian S. , Chenot S. , Tsuchizawa T. , Notomi M.
Published: June 2020

We report on GaN nanowire lasers fabricated by selective-area sublimation, and we show that sublimated GaN nanowires can exhibit ultraviolet lasing action under optical pumping beyond room temperature, up to 380 K. We study by microphotoluminescence the temperature-dependent behavior of single nanowire lasers between 7 K and 380 K and extract a characteristic temperature of T = 126 K. We finally present a statistical study of the maximum lasing temperature in individual sublimated GaN nanowires and use it to assess the performance of the selective-area sublimation method for nanowire-based lasing applications.
Three-dimensional dusty plasma in a strong magnetic field: Observation of rotating dust tori
Authors: Choudhary Mangilal , Bergert Roman , Mitic Slobodan , Thoma Markus H.
Published: June 2020

This paper reports on the dynamics of a 3-dimensional dusty plasma in a strong magnetic field. An electrostatic potential well created by a conducting or non-conducting ring in the rf discharge confines the charged dust particles. In the absence of the magnetic field, dust grains exhibit a thermal motion about their equilibrium position. As the magnetic field crosses a threshold value (B > 0.02 T), the edge particles start to rotate and form a vortex in the vertical plane. At the same time, the central region particles either exhibit thermal motion or E→×B→ motion in the horizontal plane. At B > 0.15 T, the central region dust grains start to rotate in the opposite direction resulting in a pair of counter-rotating vortices in the vertical plane. The characteristics of the vortex pair change with increasing the strength of the magnetic field (B ∼ 0.8 T). At B > 0.8 T, the dust grains exhibit very complex motion in the rotating torus. The angular frequency variation of rotating particles indicates a differential or sheared dust rotation in a vortex. The angular frequency increases with increasing the magnetic field from 0.05 T to 0.8 T. The ion drag force and dust charge gradient along with the E-field are considered as possible energy sources for driving the edge vortex flow and central region vortex motion, respectively. The directions of rotation also confirm the different energy sources responsible for the vortex motion.
Modeling of spherical dust charging in collisionless magnetized plasmas with DiMPl
Authors: Simons L. , Coppins M.
Published: June 2020

Determining the equilibrium charge of conducting spheres in plasmas is important for interpreting Langmuir probe measurements, plasma surface interactions, and dust particle behavior. The Monte Carlo code Dust in Magnetised Plasmas (DiMPl) has been developed for the purpose of determining the forces and charging behavior of conducting spheroids under a variety of conditions and benchmarked against previous numerical results. The floating potentials of spheres in isothermal, collisionless, hydrogen plasmas as a function of magnetic field strength and size relative to the Debye length are studied using DiMPl and compared with new results from the N-body tree code (pot) and recent particle in cell measurements. The results of all three simulations are similar, identifying a small range at modest ion magnetization parameters over which the electron current is reduced relative to the ion current. The potential as a function of magnetic field strength is found to be relatively insensitive to dust size for dust smaller than the Debye length. The potential of large dust is found to depend less strongly on flow speed for modest magnetic field strengths and to decrease with increasing flow speed in the presence of strong magnetic fields for smaller dust. A semi-empirical model for the potential of small dust in a collisionless plasma as a function of magnetic field strength is developed, which reproduces the expected currents and potentials in the high and low magnetic field limit.
Formation and preferential orientation of Au-free Al/Ti-based ohmic contacts on different hexagonal nitride-based heterostructures
Authors: Geenen F. , Constant A. , Solano E. , Deduytsche D. , Mocuta C. , Coppens P. , Detavernier C.
Published: June 2020

Wide-bandgap nitride semiconductors are currently in development for high-power electronic applications. Compositional layered heterostructures of such nitrides result in a high polarization field at the interface, enabling a higher electron mobility, a higher power density, and a higher conversion efficiency. Further optimization of such GaN-based high-electron-mobility transistors can be achieved by evolving from a top AlxGa1−xN barrier toward AlN or even InyAl1−yN. An ongoing challenge in using such hexagonal nitride semiconductors is the formation of a low-resistive, Au-free, ohmic contact far below 1Ωmm. In this paper, we investigate the formation of ohmic contacts by Ti–Al–TiN-based metalization as a function of different annealing temperatures (up to 950°C), Ti–Al ratios (from 15 up to 35 at. %) and nitride barrier composition (AlxGa1−xN, GaN, AlN, and InyAl1−yN). Contacts processed on AlxGa1–x/GaN, and AlN/GaN heterostructures result in low contact resistance of, respectively, 0.30 and 0.55Ωmm, whereas the same contact stack on InyAl1−yN results in resistance values of 1.7Ωmm. The observed solid-phase reaction of such Ti–Al–TiN stacks were found to be identical for all investigated barrier compositions (e.g., AlxGa1−xN , GaN, AlN, and InyAl1−yN), including the preferential grain alignment to the epitaxial nitride layer. The best performing ohmic contacts are formed when the bottom Ti-layer is totally consumed and when an epitaxially-aligned metal layer is present, either epitaxial Al (for a contact which is relatively Al-rich and annealed to a temperature below 660°C) or ternary Ti2AlN (for a relatively Ti-rich contact annealed up to 850°C). The observation that the solid-phase reaction is identical on all investigated nitrides suggests that a further decrease of the contact resistance will be largely dependent on an optimization of the nitride barriers themselves.
A low-current atmospheric pressure discharge generating atomic magnesium fluxes
Authors: Savkin Konstantin P. , Oks Efim , Yushkov Georgy , Ivanov Yurii
Published: June 2020

In the present work, we studied the stable operation of an atmospheric pressure discharge with magnesium electrodes in air and argon flows. We employed a plasma generator consisting of a central cathode and a coaxial anode. At a direct discharge current up to 200 mA, spontaneous transitions to a low-voltage (30–40 V) burning regime were observed when the current was slightly raised by several milliamperes. This phenomenon is reflected in the optical spectrum by the appearance of corresponding lines of singly charged and exited magnesium atoms. It has been found that for a discharge fed by a pulsed power supply, at a unipolar pulse repetition rate of 100 kHz, with the working gas of argon, the aerosol emission becomes stabilized. The aerosol consists of magnesium particles suspended in the argon flow that eventually mixes up with the surrounding air. Based on our estimates, we have made an assumption that the physical nature of the discharge maintenance lies in the ion–electron emission due to the interaction of argon ions with the magnesium cathode surface.
Optical spectroscopy for sputtering process characterization
Authors: Britun Nikolay , Hnilica Jaroslav
Published: June 2020

In this Tutorial, various methods of optical spectroscopy representing certain interest for magnetron discharge characterization are overviewed. The main principles, the implementation examples, and the selected results are given for each technique, accompanied by short discussions and suggestions for further reading. Both passive and active optical methods are covered, including optical absorption and laser-based techniques. The advantages and drawbacks of each diagnostic approach are critically analyzed. Special attention is devoted to the techniques extensively used by the authors in their own work, such as line ratio methods, absorption spectroscopy, interferometry, and laser-induced fluorescence.
The performance limits of epigraphene Hall sensors doped across the Dirac point
Authors: He H. , Shetty N. , Bauch T. , Kubatkin S. , Kaufmann T. , Cornils M. , Yakimova R. , Lara-Avila S.
Published: June 2020

Epitaxial graphene on silicon carbide, or epigraphene, provides an excellent platform for Hall sensing devices in terms of both high electrical quality and scalability. However, the challenge in controlling its carrier density has thus far prevented systematic studies of epigraphene Hall sensor performance. In this work, we investigate epigraphene Hall sensors where epigraphene is doped across the Dirac point using molecular doping. Depending on the carrier density, molecular-doped epigraphene Hall sensors reach room temperature sensitivities of SV = 0.23 V/(VT) and SI = 1440 V/(AT), with magnetic field detection limits down to BMIN = 27 nT/√Hz at 20 kHz. Thermally stabilized devices demonstrate operation up to 150 °C with SV = 0.12 V/(VT), SI = 300 V/(AT), and BMIN ∼100 nT/√Hz at 20 kHz. Our work demonstrates that epigraphene doped close to the Dirac point could potentially outperform III–V Hall elements in the extended and military temperature ranges.
Numerical analysis of the effect of surface recombination on N-atom in discharge and post-discharge region
Authors: Li Sen , Wang Xiaobing , Liu Yang , Cheng Qinglin , Bian Bin , Pu Hui , Ma Tingting , Tang Bo
Published: June 2020

In this paper, the effect of surface recombination on N-atom production is discussed through a one-dimensional simulation of Townsend dielectric barrier discharge in pure N2 based on a fluid model. By comparison of the experimental results, the recommended value of the sticking coefficient of N–N surface recombination is 0.5–1. The spatial-temporal distribution of N-atom of simulation results in discharge and post-discharge agree with experimental results. When the sticking coefficient is 0.5, the primary active species include N, N2(A), and N2(a′). N4+ is the densest positive ion, which can reach 4.77 × 109 cm−3. N-atom can reach the saturation level within about 30 ms. The highest number density is 3.14 × 1014 cm−3 at the position 0.25 mm away from the surface. The numerical simulation results are very consistent with the experimental results. The contribution of surface recombination and three-body recombination for the decay of N-atom are roughly equal in the post-discharge region.
In situ growth of Fe2WO6 on WO3 nanosheets to fabricate heterojunction arrays for boosting solar water splitting
Authors: Lin He , Long Xia , An Yiming , Yang Shihe
Published: June 2020

We demonstrate the construction of heterojunction arrays for boosting solar water splitting by combining in situ guided growth of heterointerfaces and energy band tuning. By directly growing an ultrathin Fe2WO6 layer on a preformed WO3 nanosheet array in full coverage, a uniform and dense array of intimately contacted WO3/Fe2WO6 heterojunction was created. The heterojunction array shows not only a largely broadened visible light absorption range but also a built-in interface polarization to accelerate hole transfer from WO3 to Fe2WO6. Meanwhile, fine-tuning to match energy levels at the heterojunction was achieved by doping WO3 with Fe (Fe-WO3), leading to improved electrical conductivity and reduced charge recombination. Photoanodes based on such heterojunction arrays have shown significantly enhanced photoelectrochemical (PEC) water splitting performance, clearly arising from the above-mentioned efforts. Furthermore, by decorating FeOOH/NiOOH cocatalysts on the heterojunction arrays in tandem, the surface water oxidation kinetics was considerably accelerated, and the resulting Fe-WO3/Fe2WO6/FeOOH/NiOOH photoanode achieved a photocurrent density of 2.78 mA/cm2 at 1.23 V vs reversible hydrogen electrode. This work highlights the benefits of in situ construction of heterojunction arrays for enhancing the PEC performance.
Effect of Pb(Zr0.52Ti0.48)O3 thin films on electron transport at the LaAlO3/SrTiO3 interface by surface acoustic waves
Authors: Uzun Y. , Doller D. , Smink A. E. M. , Nguyen M. D. , de Jong M. P. , van der Wiel W. G.
Published: June 2020

Surface acoustic waves (SAWs) are capable tools for providing mechanical control over the electronic properties of functional materials. Coupling SAWs with the LaAlO3/SrTiO3 (LAO/STO) conducting interface is particularly interesting as this interface exhibits extraordinary features, such as high mobility at low temperature, ferromagnetism, and superconductivity below 200 mK. For SAW generation, piezoelectricity is indispensable, and due to lack of that in the LAO/STO system, a 200 nm thick Pb(Zr0.52Ti0.48)O3 (PZT) film was grown on top of LAO. SAW excitation and propagation was demonstrated on a PZT/LAO/STO multilayer structure. We further employed SAWs in order to transport free electrons confined to the LAO/STO interface, detected as an acoustoelectric voltage at room temperature. Electrical characterization of the interface was carried out by Van der Pauw measurements. We found that having a PZT layer on top of LAO/STO considerably degraded the interfacial conductivity. The degradation became more pronounced at low temperatures. We attribute these effects to the filling of oxygen vacancies due to interlayer oxygen migration, combined with carrier freeze-out at low temperatures.
The elongation-criterion for fracture toughness of hydrogels based on percolation model
Authors: Li Ziqian , Liu Zishun
Published: June 2020

The fracture behavior of hydrogels is a difficult problem. Almost all theories widely used at present are based on comparisons between the energy release rate and the intrinsic fracture energy plus the extra dissipative energy. However, this methodology based on the concept of fracture energy also has its drawbacks, such as inconvenience in measurements, disregarding the complex network configurations, as well as other uncertainties in engineering. In this paper, a framework based on another perspective is proposed to reconsider the fracture behavior of hydrogels. A carefully designed network generating algorithm is used to simulate the growth process of a hydrogel network. Then, the simulated hydrogel network is transformed into a corresponding logical network to express the interaction between chains. In our theory, the elongation ratio of a hydrogel is used to build a new fracture criterion. The percolation theory is then introduced to find out the critical fracture elongation ratio. Finally, considering the uncertainties in hydrogel samples, the probability distribution of the experimental results and the theoretical predictions are compared to validate our theoretical framework.
Soft-wired long-term memory in a natural recurrent neuronal network
Authors: Casal Miguel A. , Galella Santiago , Vilarroya Oscar , Garcia-Ojalvo Jordi
Published: June 2020

Recurrent neuronal networks are known to be endowed with fading (short-term) memory, whereas long-term memory is usually considered to be hard-wired in the network connectivity via Hebbian learning, for instance. Here, we use the neuronal network of the roundworm C. elegans to show that recurrent architectures in living organisms can exhibit long-term memory without relying on specific hard-wired modules. We applied a genetic algorithm, using a binary genome that encodes for inhibitory-excitatory connectivity, to solve the unconstrained optimization problem of fitting the experimentally observed dynamics of the worm’s neuronal network. Our results show that the network operates in a complex chaotic regime, as measured by the permutation entropy. In that complex regime, the response of the system to repeated presentations of a time-varying stimulus reveals a consistent behavior that can be interpreted as long-term memory. This memory is soft-wired, since it does not require structural changes in the network connectivity, but relies only on the system dynamics for encoding.
New directions in assisted breeding techniques for fish conservation
Authors: Rivers Nicola , Daly Jonathan , Temple-Smith Peter
Published: June 2020

Fish populations continue to decline globally, signalling the need for new initiatives to conserve endangered species. Over the past two decades, with advances in our understanding of fish germ line biology, new exsitu management strategies for fish genetics and reproduction have focused on the use of germ line cells. The development of germ cell transplantation techniques for the purposes of propagating fish species, most commonly farmed species such as salmonids, has been gaining interest among conservation scientists as a means of regenerating endangered species. Previously, exsitu conservation methods in fish have been restricted to the cryopreservation of gametes or maintaining captive breeding colonies, both of which face significant challenges that have restricted their widespread implementation. However, advances in germ cell transplantation techniques have made its application in endangered species tangible. Using this approach, it is possible to preserve the genetics of fish species at any stage in their reproductive cycle regardless of sexual maturity or the limitations of brief annual spawning periods. Combining cryopreservation and germ cell transplantation will greatly expand our ability to preserve functional genetic samples from threatened species, to secure fish biodiversity and to produce new individuals to enhance or restore native populations.
COP1 destabilizes DELLA proteins in
Arabidopsis
Authors: Blanco-Touriñán Noel , Legris Martina , Minguet Eugenio G. , Costigliolo-Rojas Cecilia , Nohales María A. , Iniesto Elisa , García-León Marta , Pacín Manuel , Heucken Nicole , Blomeier Tim , Locascio Antonella , Černý Martin , Esteve-Bruna David , Díez-Díaz Mónica , Brzobohatý Břetislav , Frerigmann Henning , Zurbriggen Matías D. , Kay Steve A. , Rubio Vicente , Blázquez Miguel A. , Casal Jorge J. , Alabadí David
Published: May 2020

Significance

DELLA proteins are plant-specific transcriptional regulators that act as signaling hubs at the interface between the environment and the transcriptional networks that control growth. The growth-promoting hormone gibberellin destabilizes DELLAs. Here we describe an alternative pathway to destabilize these proteins. We show that DELLAs are substrate of COP1, an E3 ubiquitin ligase that increases its activity to promote growth in response to shade or warmth. Our results show that COP1, and not changes in gibberellin levels, mediates the rapid destabilization of DELLAs in response to environmental cues.
Redox controls metabolic robustness in the gas-fermenting acetogenClostridium autoethanogenum
Authors: Mahamkali Vishnuvardhan , Valgepea Kaspar , de Souza Pinto Lemgruber Renato , Plan Manuel , Tappel Ryan , Köpke Michael , Simpson Séan Dennis , Nielsen Lars Keld , Marcellin Esteban
Published: May 2020

Living biological systems display a fascinating ability to self-organize their metabolism. This ability ultimately determines the metabolic robustness that is fundamental to controlling cellular behavior. However, fluctuations in metabolism can affect cellular homeostasis through transient oscillations. For example, yeast cultures exhibit rhythmic oscillatory behavior in high cell-density continuous cultures. Oscillatory behavior provides a unique opportunity for quantitating the robustness of metabolism, as cells respond to changes by inherently compromising metabolic efficiency. Here, we quantify the limits of metabolic robustness in self-oscillating autotrophic continuous cultures of the gas-fermenting acetogenClostridium autoethanogenum. Online gas analysis and high-resolution temporal metabolomics showed oscillations in gas uptake rates and extracellular byproducts synchronized with biomass levels. The data show initial growth on CO, followed by growth on CO and H2. Growth on CO and H2results in an accelerated growth phase, after which a downcycle is observed in synchrony with a loss in H2uptake. Intriguingly, oscillations are not linked to translational control, as no differences were observed in protein expression during oscillations. Intracellular metabolomics analysis revealed decreasing levels of redox ratios in synchrony with the cycles. We then developed a thermodynamic metabolic flux analysis model to investigate whether regulation in acetogens is controlled at the thermodynamic level. We used endo- and exo-metabolomics data to show that the thermodynamic driving force of critical reactions collapsed as H2uptake is lost. The oscillations are coordinated with redox. The data indicate that metabolic oscillations in acetogen gas fermentation are controlled at the thermodynamic level.
Recycling a genre for news automation
Authors: Haapanen Lauri , Leppänen Leo
Published: May 2020

The amount of available digital data is increasing at a tremendous rate. These data, however, are of limited use
unless converted into a user-friendly form. We took on this task and built a natural language generation (NLG) driven system that
generates journalistic news stories about elections without human intervention. In this paper, after presenting an overview of
state-of-the-art technologies in NLG, we explain systematically how we identified and then recontextualized the determinant
aspects of the genre of an online news story in the algorithm of our NLG software. In the discussion, we introduce the key results
of a user test we carried out and some improvements that these results suggest. Then, after relating the news items that our NLG
system generates to general aspects of genres and their evolution, we conclude by questioning the idea that journalistic NLG
systems should mimic journalism written by humans. Instead, we suggest that developmental work in the field of news automation
should aim to create a new genre based on the inherent strengths of NLG. Finally, we present a few suggestions as to what this
genre could include.
Quoting to persuade
Authors: Cope Jen
Published: May 2020

This paper examines how quotations are linguistically constructed by expert contributors in US, UK, and Australian opinion texts, vis-à-vis their form, function, and processes. Cope’s (2016) study found that authoritative expert contributors integrated a considerable number of quotations on blame and responsibility for the global financial crisis in single-authored US, UK, and Australian opinion texts. By examining the form, function, and processes of quoting in this paper, she found evidence that quoting is an intertextual form of positioning. Empirically grounded linguistic analyses investigate the language of quoting frames – how the quoted source is specified, the quoting verb used, e.g., strong meanings (demanded, thundered, promised) or neutral (said, told) – and evaluate the language of propositional content in quotations. Such analyses reveal authorial positions taken in quoting. A greater number of quotations incorporated by general newspaper opinion authors, than by specialized financial newspaper opinion authors, furthermore implies that quoting increases a writer’s authority in non-specialized media sources. The specially created integrated linguistic framework draws on Martin & White’s (2005) Appraisal system from systemic-functional linguistics, White’s (2012, 2015) attribution and endorsement, and Bazerman’s (2004) intertextuality techniques. Contextual factors in language use and quoting are evaluated throughout. This paper thus provides evidence of, and implications for, quoting in cross-cultural opinion texts, and contributes to knowledge on the increasingly mediatized practice of language recycling and to media literacy.
Bidirectional transfers of the ditransitive construction in Chinese
Authors: Shi Yuzhi
Published: June 2020

The Chinese ditransitive construction expresses the ‘bidirectional’ transfers: the movement of the patient either (a) from the subject to indirect object or (b) from the indirect object to subject, a feature that has not been identified in other languages. This construction is thus different from the ditransitive construction in English and other languages whose ditransitive constructions can express only a ‘single-direction’ transfer: the movement of the patient from the subject to indirect object only. This article addresses the reason for the unusual functions of the ditransitive construction in Chinese. A parallel difference between these two languages is found in the semantic structures of those ditransitive verbs: Chinese coins a single verb to express the same type of ‘transfer’ action with opposite directions, but English usually invents two distinct verbs to denote the two antonymous meanings whose directions are opposite; e.g., the Chinese verbjièsubsumes the meanings of bothborrowandlendin English. This article argues that the different meanings of the ditransitive constructions of Chinese and English result from the different conceptualizations of their ditransitive verbs. In construction grammar, the following question remains unanswered: where does the meaning of the construction come from? The present analysis provides evidence that the meanings of the verbs within the construction are capable of determining the meaning/function of the whole construction.
The overt pronoun penalty for plural anaphors in Spanish
Authors: Gelormini-Lezama Carlos
Published: June 2020

In null-subject languages, sentences with singular overt pronouns are read more slowly than sentences with singular null pronouns when the referent is prominent (Gelormini-Lezama & Almor, 2011). In a self-paced reading task, we tested 20 Spanish speakers to examine whether this processing delay extends to plural pronouns. Each item consisted of two sentences. The first sentence introduced two arguments with the same or different thematic roles. The second sentence contained a plural (null or overt) pronoun. Results showed that sentences with overt pronouns were read significantly more slowly than sentences with null pronouns, only when the two arguments had the same thematic role. This plural overt pronoun penalty heavily depends on semantic rather than on purely syntactic factors.
On the origins of Portuguese para form variation
Authors: Gradoville Michael
Published: June 2020

This study explores the origins of Brazilian Portuguese para ‘to, for’ form variation using sociophonetic analytic techniques to test various properties of the unreduced para variant. While the pra variant was suggested to have originated from an intertonic syncope process, the finding in this study that unreduced para is produced with lexical stress calls such an origin into question. Since unreduced para o tends to be produced lacking the second /a/, para + Article’s low reduction rate to pra in previous studies may be a consequence of its participation in a word-boundary reduction process. Reduction of para to pra therefore appears to be a case of special reduction that emerged for para to reduce a syllable in other contexts.
Narrative affordances
Authors: Noy Chaim
Published: June 2020

Museums offer rich material environments for studying narration as jointly accomplished by institutions and audiences. Following the narrative and participatory turns museums have taken, the research explores the narrative actions audiences’ texts perform vis-à-vis museums’ narrations. It examines audience participation in two history museums, as elicited by response vehicles – onsite media that serve to invite and capture audience written responses. The research argues that museum response vehicles offer narrative affordances and entitlements, which shape how audiences negotiate participation as publicly documented and displayed. Comparative findings indicate that participation is shaped by response vehicles’ spatio-material affordances, including how brief textual segments function as audience-based contributions in and to the historical narration. A range of audience-generated narrative actions, entitlements, and speech acts are discerned and discussed, which typically conform with, but sometimes ‘override’, museums’ affordances. These narrative actions shed light on the mechanics, politics and policies of public narration and agency.
The role of interdialectal forms in the formation of koinai
Authors: Almeida Suarez Manuel
Published: June 2020

The study of the changes that are taking place in European dialects reveals the existence of opposing tendencies: convergent, leading to homogenisation, and divergent, promoting diversity. This paper aims to analyse a case of dialect divergence in a speech community in the Canary Islands through the study of a series of linguistic and social factors that constrain the alternation between two phonetic forms: the lax and tense variants of the plosive palatal /c/, lax /c/ being the traditional form and tense /c/ being the innovative variant. The new form, [cʃ], can be considered as an interdialectal or hybrid variant, since it contains features from the corresponding standard form, /tʃ/, and the vernacular one, /c/. The analysis of sociolinguistic factors enables a more precise understanding of the way in which the hybrid variant contributes to delaying the language homogenisation observed in other levels of the dialect.
Towards a better understanding of breeding objectives and production performance of dairy cattle in sub-Saharan Africa: a systematic review and meta-analysis
Authors: Chawala A.R. , Mwai A.O , Peters A. , Banos G. , Chagunda M.G.G.
Published: May 2020

The aim of this study was to examine breeding objectives and the impact of production systems and breed types on dairy cattle performance in sub-Saharan Africa (SSA). A total of 64 research studies published between 1980 and 2018 were used for qualitative analysis (qualitative synthesis) of farmers’, scientists’ and institutional dairy trait preferences. Meta-analysis was conducted to examine the production and reproduction performance of dairy cattle in smallholder and large-scale dairy production systems. Most data used were from smallholder farmers (60%), with the remainder from large-scale farms. Linear mixed-effect models were used to estimate marginal means of production and reproduction traits for different breed types in both production systems. Overall, the results showed that there was a higher emphasis on breeding for improved fertility, increased milk yield and disease resistance. Milk content (fat and protein percentages), temperament, body conformation and total milk cell count (a mastitis indicator) were rarely mentioned in published literature, mainly because of milk pricing policies being volume based. Frequency and multivariate analyses (cluster data analysis) for desirable animal traits suggested that multiple breeding objectives are needed, based on the perceived goals of different farmers and institutions towards genetic improvement for production, reproduction, disease resistance and functional and animal welfare traits. Regardless of the breed type, commercial large-scale farms had a higher milk yield (2857.0 ± 233.3) compared with smallholder dairy farms (2419.8 ± 617.39). Estimated marginal means for lactation milk yield of the three breed types Holstein-Friesian, non-Holstein-Friesian dairy breeds (Jersey, Guernsey, Red Dane, Brown Swiss and Ayrshire) and cross-breds (
Bos taurus x Bos indicus
) were 3148.5 ± 433.00, 2995.6 ± 456.36 and 1771.1 ± 328.52, respectively. Significantly shorter age at first calving and shorter calving intervals were observed in large-scale farms in comparison to smallholder farms (
p
 < 0.05). No significant differences were noted for age at first calving, calving interval, days open and number of services per conception between the breed types. In conclusion, the present study suggests that (i) improvement of dairy cattle has focused on reproduction, production and disease resistance traits, reflecting the breeding objectives of farmers, scientists and institutions involved in dairy production; (ii) genetics plays a large role in increased dairy productivity in SSA and (iii) future dairy research should emphasise on the interactions between improved feeding, disease control and genetics at a production level to inform profitable combinations of dairy traits.
The broiler chicken production value chain in Nigeria between needs and policy: situation analysis, action plan for development, and lessons for other developing countries
Authors: Oloso Nurudeen Olalekan , Smith Peter William , Adeyemo Ismail Adewuyi , Odeokun Ismail Ayoade , Isola Tajudeen Opeyemi , Fasanmi Olubunmi Gabriel , Fasina Folorunso Oludayo
Published: May 2020

Poultry production is important in Nigeria and other developing economies, mainly because it provides much-needed employment and is crucial for food security. The Nigerian broiler production system is relatively disorganized and its structures are relatively undefined due to a dearth of information. Broiler industry’s development depends on some factors including input–output systems, stable policies, focused development plans, competitive marketing, and cutting-edge technologies. To understand these factors, the industry’s policy review, field survey, and market analysis were carried out. Findings confirmed that policy was inconsistent and inadequate, prices of local products were higher than those of smuggled (illegal imports) comparative products and local producers were under pressure internally because the input–output system put additional stress on the system with attendant high risks of food safety and security. While the Nigerian broiler industry has tremendous potential for expansion, stakeholders’ engagement in policy formulation and implementation, a systematic national development plan, updates of redundant laws and regulations, and an overall improvement in biosecurity including the determination of critical control points are necessary. Similarly, cross-national and trans-border synergistic activities should be engaged by regulators, and it is important to engage comparative adaptive research to draw benefits from other developing countries with functional and developed broiler industries, which should benefit the Nigeria broiler industry.
Orphan crops in Burkina Faso and Niger: a systematic review
Authors: Bilali Hamid El
Published: May 2020

Humanity faces unprecedented, interlinked challenges to achieve sustainable development (e.g., climate change, food and nutrition insecurity, livelihoods vulnerability and poverty, biodiversity loss, and ecosystem degradation). Orphan crops (i.e., neglected and underutilized species) are put forward by many scholars and practitioners to address these challenges, especially in developing countries of the Global South. However, the development of orphan crops requires investments in research and innovation. Therefore, this paper analyses the landscape of research dealing with orphan crops in Burkina Faso and Niger. The systematic review—drawing upon a search carried out on Scopus in November 2019—provides an overview on both the bibliographical metrics (journals, subject areas, authors, institutions, countries, and funding) and the topics addressed (species, food chain stages, climate change, food security and nutrition, and livelihoods). Available scholarly literature focuses on the production stage and on biological sciences; social sciences and economics are underserved. The review shows that although orphan crops are resilient, nutritious, and adapted to marginal agro-ecosystems, research dealing with them is still marginal and at an early stage of development in both countries. Therefore, the paper highlights the urgent need to strengthen research on orphan crops within the Agricultural Knowledge and Innovation Systems (AKIS) of both countries. For that, both domestic funding and international support are needed to implement a long-term agenda for research and development on these crops.
CD142 plays an important role in the mobility of colorectal cancer cells
Authors: Gao Qin , Chen Zhongbiao , He Yang , Hou Zhibin , Ye Ruifeng , Xue Wanlin , Lin Jiahui , Tu Xiaohuang
Published: May 2020

CD142 promotes cell mobility, which contributes to carcinogenesis. However, the role of CD142 on colorectal cancer (CRC) mobility is unclear. This study showed that CD142 expression increased in CRC tissues, especially in those with invasion or metastasis. The positive sorting or overexpression of CD142 promoted the invasion and migration of CRC cells. Overall, CD142 may be responsible for CRC mobility.
A rapid and high-accuracy rotation alignment method based on bidirectional process for dual-axis rotational inertial navigation system
Authors: Xu Changshen , Miao Lingjuan , Zhou Zhiqiang , Lin Yusen
Published: May 2020

For the alignment in rotational inertial navigation system (RINS), which takes velocity errors of the navigation calculation as the filter measurements, the velocity error term caused by the coupling of the accelerometer’s inner lever arms (ILAs) and the gimbals’ angular motion will lead to a decline in the alignment accuracy. In view of that, a simplified model of the ILAs is proposed firstly in combination with the specific dual-axis rotation scheme, and then the ILAs are extended into state variables for filtering estimation, thereby improving the alignment accuracy. On this basis, in order to further improve the alignment rapidity, the bidirectional process-based rotation alignment method for dual-axis RINS is proposed in this paper. The bidirectional process, which combines the backward-forward RINS calculation and the backward-forward Kalman filtering, makes the best use of the stored IMU data repeatedly and is able to quickly obtain the IMU attitude matrix for RINS. The simulations and experiments show that the proposed bidirectional process-based rotation alignment method is able to accomplish the rapid and accurate alignment for the dual-axis RINS.
Control of mobile chaotic agents with jump-based connection adaption strategy
Authors: Zhou Jie , Zhou Yinzuo , Xiao Gaoxi , Stanley H Eugene
Published: June 2020

The connection adaption strategy (CAS) has been proposed for the synchronization of networked mobile chaotic agents, which is considered to be a simpler scheme compared to commonly used coupling adaption strategies. However, this strategy only provides a limited range of feasible coupling strength allowing a success control. In this paper, we develop the CAS by introducing a jump process to resolve this problem. We show that the proposed approach systematically outperforms the original CAS in the whole range of the mobility and the range of feasible coupling strength is extensively expanded. In addition, we show that motion of the agents could be classified into three different regimes. The dynamical features of these motion regimes are analyzed and relevant measures are provided to characterize the controllability of the network in each regime.
Comparative Investigations onthe Main Elements of Carbon Fiber Based Composites Using Computational Structural Simulations
Authors: Raj Kumar G , Vijayanandh R , Venkatesan K , Ramesh M , Senthil Kumar M , Balaji S
Published: May 2020

A numerical investigation on main elements of composite material could provide the clear view on the selection of main elements for the construction of composites. The lifetime of composite material is basically depends upon the chemistry between reinforcement and matrix. Also, the improvements of properties in composite are based on the main elements. Therefore the comparative studies on main elements of composite could provide suitable components for composite, which have the high capability to provide high mechanical properties. In this work, a dog-bone shape test specimen is selected as fundamental component, which is modeled with the help of Design Modeller 16.2. Utterly, 25 test specimens are constructed depends on the fiber directional angle of the reinforcements for structural analysis. The numerical simulations on 40 specimens are executed completely and then comparative analyses are carried out. Finally, after the comparison, both reinforcement and matrix are optimized for tensile loading conditions.
Estimation of Loading-Driven Fluid-Flow Pattern in Lacunar-Canalicular Space Using Fluid Structure Interaction
Authors: Kumar Rakesh , Khana Salil , Tiwari Abhishek Kumar , Tripathi Dharmendra , Sharma Niti Nipun
Published: May 2020

Bone cells namely osteoblasts and osteocytes are assumed responsible for loading-induced osteogenesis. Osteocytes lie within the bone and connect to each other via cell process passing through canalicular spaces which forms a canalicular network. Fluid motion across this network acts as a medium of communication with neighbouring cells. Mechanical loading-induced pressure gradients in lacunar canalicular space (LCS) causes canalicular fluid to flow. However, it remains unclear how canalicular fluid motion and solid structure interact with each other under loading derived strain environment. In the present study, a two-way fluid structure interaction model is developed to estimate canalicular fluid flow behaviour. Flow streamlines and wall shear stress are computed. Results indicates that wall shear due to fluid flow on the pores wall is also in the same pattern as the velocity streams and velocity is maximum at those regions where the wall shear is also maximum. The outcomes provide a better understanding for developing strategies to enhance the fluid flow in bone, which may ultimately be useful in the development of effective countermeasure for the reversal of bone loss.
Mhd flow of nanofluids in the presence of porous media, radiation and heat generation through a vertical channel
Authors: Mehta R , Chouhan V S , Mehta T
Published: May 2020

Aim of present study is to identify the effects of radiation and heat generation in unsteady MHD mixed convective flow of nanofluids along a upstanding channel through porous medium. Four types of nanofluids were studied (i) Water based – Ag (ii) Water based – Al2O3. Water is taken as convectional base fluid and Ag and Al2O3 particles are incorporated in this base fluid. Keeping in mind the congregating and random motion of nanoparticles, “Koo and Kleinstreuer model” is used. The main characteristics of the nanofluids have finer thermo physical properties such as high thermal conductivity, minimal bloking in flow passage, long term solidity and uniformity. The governing boundary layer equations are formulated and reduced to a set of ordinary differential equations using perturbation technique. Solutions are obtained for motion and temperature, discussed and pertinent results are shown through graphs.
VI Congress on Innovation and Appropriation of the Technologies of Information and Communications
Authors: Bayona-Ibáñez E , Sandoval-Amador A , V-Niño E D
Published: May 2020

The International Congress on Innovation and Appropriation of the Technologies of Information and Communications (CIATIC) is an initiative of the Network of Computer Engineering and Related Programs of North-Eastern Colombia. Accordingly, the CIATIC is a space for promoting and developing innovation and appropriation of information and communication technologies by facilitating the exchange and transfer of knowledge through the presentation of research advances in technological trends, as well as allowing the creation of collaborative networks to generate research and innovation in the field.

The sixth version of the International Congress on Innovation and Appropriation of the Technologies of Information and Communications (VI CIATIC) was held in the municipality of Ocaña, in the department of Norte de Santander, Colombia, on 25-27 September 2019. The “Universidad Francisco de Paula Santander, Seccional Ocaña”, Colombia, hosted the event. The universities that participated in 2019 as co-organizers of the Congress and are part of the Northeast region were: Universidad Pontificia Bolivariana (UPB), headquarter Bucaramanga, Universidad Autónoma de Bucaramanga (UNAB), Universidad Popular del Cesar (UPC), headquarter Aguachica, Fundación Universitaria de San Gil (UNISANGIL), and the Universidad Francisco de Paula Santander (UFPS), headquarters San José de Cúcuta and Ocaña. The participation of the universities, contributed to the internationalization, with the participation of professors and researchers from different countries of the American and European continent, such as, Mexico, United States, Ecuador, Sweden, Venezuela, Chile, and of course, Colombia, which allowed strengthening the research processes and know the different current trends on information and communication technologies.

List of Organizing Committee, International Scientific Committee, National Scientific Committee and Sponsors are available in this pdf.
Development of a monitoring module for physical and virtual servers: Advanced computing center case of the Universidad Pontificia Bolivariana, Bucaramanga, Colombia
Authors: Mantilla K I , Flórez A
Published: May 2020

The management and administration of physical and virtual servers requires a series of periodic activities that allow to show the optimal operation and the fulfillment of its objective of providing computational services. The work of monitoring servers allows the allocation and use of adequate resources, as well as assertive decision making in strategies for projection and scalability of resources. This article presents the results found in the process of development and implementation of the monitoring module of physical and virtual servers of the Advanced Computing Center of the Universidad Pontificia Bolivariana, Bucaramanga, Colombia, in which through the generation and display of reports in real time offer the coordinator of the center information of the current state of resources leading to the right decisions to improve the service provided at the level of efficiency, performance, among others. The results of the project were the design of the graphical interface, the development of the information system which was programmed with PHP language, the connection in real time with physical and virtual server made via SSH; the scripts programmed in platforms such as XenServer, Windows Server and Linux for CentOS, Debian and Ubuntu distributions.
Information and communications technologies in androgynous learning
Authors: Cárdenas García F M , Cárdenas García M , de J Cañizares Arévalo J
Published: May 2020

The globalization of the economy, information and communications has allowed the social dynamics to be competitive, leading to social transformations, to respond to these demands they require new educational approaches as an alternative in the transformation of environments in line with the globalized world. The information and communication technologies used as an educational resource play an important role, facilitating the interaction, transport and dissemination of knowledge to remote places, where androgynous learning is required, a fundamental option for the formation and training of society, which leads us to reflect about the actions of teaching in adult education. The methodology used was based on the qualitative paradigm supported by phenomenological research methods, hermeneutics and ethnomethodology allowing close relationship with key informants, triangulation was used as a strategy to correct distortions. As results, the theoretical, epistemological foundation framed in significant elements that are derived from ontological, gnoseological, philosophical, pedagogical and andragogical postulates is established, establishing pedagogical conceptualization. In conclusion, it is considered that teaching models constitute the path for the transmission of knowledge, it is there that the technological tools of information and communications become facilitating means in the teacher-student interaction, allowing the efficient development of curricular activities.