bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Relative Age Effect on Mathematics Achievement
Authors: Ünal Ali
Published: May 2019

The timing of children’s start to school is the interest of researchers, policy-makers and especially parents. Researches on this issue have recently pointed to the concept of relative age effect (RAE). The purpose of this study is to determine the impact of RAE on mathematics achievement in Turkey. In order to accomplish this purpose, the question was sought: Does RAE have an impact on TIMSS 2015 the fourth and eighth grades mathematics scores of Turkey? The research was conducted in survey model. In the present study, the data obtained from the TIMSS 2015 results of Turkey was used. Totally 6456 students were sampled for TIMSS 2015 the fourth grade in 242 schools. Also, totally 6079 students (2943 girls and 3136 boys) were sampled for TIMSS 2015 the eighth grade in 218 schools. Hierarchical multiple regression analysis was used to analyze the data. In conclusion, it has been reached that RAE has an impact on TIMSS 2015 the fourth and eighth grades mathematics scores of Turkey and the youngest children born just before the cut-off date has the worst performance. The recommendations based on the results have been submitted as making the enrollment dates more flexible, especially for children in rural areas, not applying honors classes in schools, raising awareness about RAE in pre-service and in-service training programs for teachers, no pressure on children at home and at school for their lagging in competition.
Investigating Primary School Teachers’ Knowledge Towards Meanings of Fractions
Authors: Doğan Adem , Tertemiz Neşe Işık
Published: May 2019

The concept of fraction and the concepts related to the fraction have an important place in primary and secondary school education programs. In this respect, primary school teachers need to be careful about the concept and sub-meaning of the fraction. In this study, general survey model was used to determine the level of knowledge of the primary school teachers about the meaning of fractions. A total of 266 primary school teachers (149 female and 117 male) participated in the study in Turkey. For collecting data, a success test was developed by the researchers about the meaning of the fraction. The data were analyzed by using SPSS 21 package program. The general success average of the teachers was found to be 60.2%. The most successful sub-meaning of the fraction is the operator meaning with 80% and the least successful meaning is ratio meaning with 48%. Furthermore, it was concluded that there is a positive correlation with each other in all sub-meanings fractions.
Graduation Profiles of Pedagogy Programmes According to the Current Educational Policies
Authors: Medina Jessica C. , González José A.
Published: May 2019

The research analyzes the graduate profiles of pedagogical careers belonging to the universities of the Valparaíso region, Chile. For this purpose, a metrically consistent instrument has been proposed and created, according to the main Education Policies of the country that is called as an integral profile, which includes aspects with which Chilean teachers are evaluated, plus indicators of inclusion and citizen education. These Policies are not always measured, that’s why universities give such importance to these three educational policies. For these reasons, the objective of this article is to analyze, based on quantitative techniques, the relation of similarity between graduation profiles and educational policies, contributing to empower the descended aspects and to visualize the importance that the universities grant to train students with an integral profile. The results of this research invite to promote the Educational Policies related to the exit profiles of the pedagogical careers, since having integral profiles contributes to form a model of teacher training for the country, especially in those with emerging economies, such as those of Latin America.
Physico-chemical Characteristics of Selected Jackfruit (Artocarpus Heterophyllus Lam) Varieties
Authors: Balamaze J. , Muyonga J. H. , Byaruhanga Y. B.
Published: May 2019

This study was aimed at establishing the variation in physico-chemical properties between and within different jackfruit varieties.

Mature jackfruits from trees known to produce orange, yellow and white flakes were harvested and ripened at 28oC and 90% relative humidity. The weight, length and circumference of ripe fruits were measured. The fruits were cut into three equal sections: top, middle and bottom. Each section was separated into flakes, rind, abortive perigones, consolidated perigones, seeds and core. The percent weight of different fruit parts, and flake physico-chemical characteristics were determined.

The average weight, length, circumference and maturation period for jackfruit varieties studied were 12 kg, 47 cm, 76 cm and 104 days, respectively. The mean proportions of flakes, rind, abortive perigones, consolidated perigones, seeds and core were 24.7, 20.0, 14.5 14.3, 13.1 and 11.3%, respectively. Ascorbic acid (AA), carotenoids, total soluble solids (TSS), TSS: acid ratio, color and texture varied significantly among jackfruit sections. Color did not vary among sections of yellow and white flaked varieties. Flake texture (hardness) was 12.1, 10.5 and 6.6 N/mm for the white, yellow and orange flaked varieties, respectively. Flake textural resilience was in the order: white > yellow > orange flakes. Principle component analysis showed white flakes correlated positively with flake resilience, hardness and color lightness. Orange flakes were associated with high carotenoids and TSS content. Yellow flakes exhibited intermediate properties between those of white and orange flakes. Jackfruit flake color and section can be used as flake quality predictor.
The Level of Applying Ergonomic Factors in Work Environment at the World Islamic Sciences University and Its Influence on Decreasing Management Problems from the Perspective of Staff Members
Authors: Khawaldeh Mohammed Falah Ali
Published: May 2019

This study aims to unravel the level of applying ergonomics, and its influence on decreasing management problems in work environments at the World Islamic Sciences University, henceforth (WISE U.), from the perspective of staff members. To achieve the goals of the study, the descriptive method was adopted. Sample of the study consisted of (94) staff members.

Two questionnaires were designed: the first is on ergonomics which consisted of four dimensions: the human, the structural and the technical and technological. The second questionnaire was on decreasing management problems. The results revealed that staff members assessment for ergonomics with all its dimensions was medium, while their assessment for decreasing management problems was high.

It was also found, from the perspective of staff members, that applying ergonomics with the purpose of decreasing management problems in the university was high, excluding the application of technical dimension.
PRECONCEITO DE GÊNERO NO AMBIENTE ESCOLAR: A FORMAÇÃO DOCENTE E A DISCIPLINA DE GEOGRAFIA COMO PROMOTORAS DE UMA EDUCAÇÃO CIDADÃ
Authors: Almeida Jacqueline Praxedes , Calazans Denis Rocha , Bomfim Jaqueline Silva , Oliveira Jeremias Ferreira
Published: May 2019

O Brasil ocupa o 7º lugar no mundo em casos de feminicídios e o estado de Alagoas ocupa o 3º lugar no ranking nacional. Nessa perspectiva, o presente trabalho, enfoca a necessidade da importância de uma formação profissional do professor, em especial o de Geografia, para promover uma educação voltada para o respeito às diferenças, contribuindo para a efetivação de uma educação para todos. Nesse estudo de natureza qualitativa optou-se pelo questionário como instrumento de recolha de dados. A investigação realizada com os alunos do Ensino Médio de uma escola pública de Maceió/AL, revelou, que um percentual significativo dos discentes inquiridos banalizam ações machistas e que desvalorizam a mulher.
REPENSAR O PAPEL DA EDUCAÇÃO AMBIENTAL DIANTE DE UM PROJETO DE FUTURO: UMA PROPOSTA A PARTIR DA MANDALA DA ECOPEDAGOGIA
Authors: Figueiró Adriano Severo , Silva Greice Perske
Published: May 2019

A humanidade vive um momento histórico marcado por profundas mudanças e transformações na relação sociedade/natureza. E nessa era de transformações sociais, políticas e econômicas em que se encontra o mundo, a Educação Ambiental tem sido muito focada em função da crise que a sociedade moderna encara. Essa crise se agrava na medida em que o homem aumenta seu poder de intervenção no meio natural, aumentando, consequentemente, as tensões na sua relação com a natureza. As desigualdades sociais e a degradação dos recursos naturais acrescem com o processo de globalização, consequência do modo de produção dominante, o qual induz à competitividade, ao individualismo e ao consumo, diante de um quadro em que a própria Educação Ambiental tradicional tem capitulado diante das armadilhas de um “capitalismo verde”. Para reverter este quadro, torna-se cada vez mais imprescindível a refundação de um viés crítico da Educação Ambiental, capaz de conduzir à construção de um processo de tomada de consciência acerca da necessidade de modificarmos as atitudes perante a natureza e à sociedade. Neste artigo nós propomos o uso de uma mandala da ecopedagogia como um instrumento para a reflexão e a organização das atividades de educação ambiental dentro da escola, construída com base em seis princípios, campos temáticos e eixos de ação, levando em conta o potencial transformador da educação ambiental.
Character strengths, sociodemographic characteristics, and life satisfaction in Mexican students
Authors: Ruvalcaba-Romero Norma Alicia , Gallegos-Guajardo Julia , Alfaro-Beracoechea Laura N. , Orozco-Solís Gabriela
Published: May 2019

The main purpose of this study was to identify the existing relationship between character strengths and life satisfaction, as well as some sociodemographic aspects related to gender differences. Both the Virtue and Strength Inventory (IVYF; Cosentino & Castro, 2008) and the Satisfaction with Life Scale (SWLS; Diener, Emmons, Larsen & Griffin, 1985) were administered to 343 undergraduate students whose primary major of study pertained to health professions. Results indicated that for women, love and gratitude are the strengths that explained 21.3 % of the variance regarding satisfaction with life, while love and social intelligence predicted 44.5 % of life satisfaction for men. Results are discussed under the light of cultural differences.
Revisión de la autocaracterización: una técnica narrativa constructivista
Authors: González Encinas Javier , Saúl Gutiérrez Luis Ángel , García Martínez Jesús
Published: May 2019

ResumenLa autocaracterización es una técnica narrativa enmarcada dentro de la Teoría de los Constructos Personales (Kelly, 1955). Se diferencia de otras técnicas narrativas por la estructura de sus instrucciones, donde se solicita a la persona describirse a sí misma en tercera persona de una forma íntima; y por el formato de corrección, que trata de desenfocar al lector de su visión y asumir el punto de vista del autor como propio, así como por explorar el proceso y el sistema de construcción personal. Pese a ser destacada por su utilidad clínica (G. J. Neimeyer, 1996), no se han encontrado trabajos que reúnan los principales resultados que ha cosechado esta técnica. El objetivo de la presente investigación es analizar las similitudes y las diferencias encontradas en los trabajos que hacen uso de ella. Para dar respuesta, se lleva a cabo una revisión de literatura que reúne las principales contribuciones sobre la autocaracterización. Se ha tenido en cuenta la metodología empleada en los estudios, el formato de instrucción y de corrección y las etapas de análisis. La investigación muestra que el acercamiento crédulo, la flexibilidad de las instrucciones y la exploración de los constructos personales son los puntos recurrentes en los distintos trabajos recopilados. Se concluye que el formato de corrección, escasamente sistematizado, está influyendo negativamente en su uso y en su difusión a nivel empírico. Adicionalmente, se indica la necesidad de generar un protocolo de análisis que integre las principales etapas de análisis y actitudes del terapeuta que más atención han cosechado.AbstractSelf-characterization is a narrative technique framed in Personal Construct Theory (PCT; Kelly, 1955). It is differentiated from others narrative techniques by its elicited instructions, where is request a third person selfdescription in a sympathetic and intimate way, and by analysis protocol, that try to blur the reader from his own vision and assume the author’s point of view as his own, like so explore the process and the system of personal construct. Despite being highlighted for therapeutic useful (G. J. Neimeyer, 1996), no works founds that gather the self-characterizations finds. The objective is analyzing the differences and similarities founded between research which use self-characterization. For give an answer, it is made a literature review that group the main contributions about this technique. It has been taken in consideration the methodology, instructions and analysis format, and analysis phases. This paper sample that credulous approach, instruction flexibility and personal construct exploration are the recurrent point in compiled works. It is been concluded that analysis format, poorly systematized, supposes a negative influence in its use and diffusion at empiric level. Additionally, it is indicated the need to generate a new protocol to analysis that integrated the principal phases and therapeutic attitude that have garnered more attention.
A recolocação do idoso no mercado de trabalho: percepção dos graduandos em administração da Faculdade Maurício de Nassau
Authors: Santos Keila Oliveira dos , BÃ¶hmer Tatiane Heinemann
Published: May 2019

A pesquisa trata-se de um assunto que diz respeito a todos e aborda uma nova inclusão social, onde a sociedade brasileira, diante de um mundo globalizado e economicamente capitalista, estabelece padrões, como a faixa etária na inserção do profissional no mercado de trabalho. Por ser um problema atual, onde muitos idosos necessitam trabalhar, e, ao tentarem se recolocar no mercado de trabalho, acabam tendo bastante dificuldade, assim optou-se por verificar qual a visão de futuros administradores diante dessa questão, além de buscar a verificação se estes “jovens” estão preparados para o cenário que se apresenta em relação ao mercado de trabalho e a terceira idade. Para isso, realizou-se uma pesquisa junto aos alunos do curso de Administração da Faculdade Maurício de Nassau na Unidade Aracaju/SE. Utilizou-se como ferramenta um questionário estruturado contendo 15 perguntas abertas e fechadas a fim de analisar quantitativa e qualitativamente as respostas fornecidas. Como forma de análise, foi realizada estatística descritiva, bem como análise de discurso.
Controle de estoque alimentício em um restaurante de culinária oriental
Authors: Santos Jane Clesia Paiva dos , BÃ¶hmer Tatiane Heinemann
Published: May 2019

A fim de superarem momentos de crise e se manterem ativas e gerando resultados positivos, empresas buscam fazer adaptações que minimizem os gastos e gerem lucros. Dentre estas medidas adotadas, o controle de estoque se destaca como medida eficaz na redução de perdas e desperdícios, mantendo a qualidade dos produtos e gerando economia. O objetivo principal desta pesquisa é expor a importância do controle de estoque alimentício em um restaurante de comida chinesa, situado em um dos shoppings da capital sergipana, bem como definir as características e os impactos da ausência do controle de estoque, além de verificar como é realizado esse controle no estabelecimento em estudo. Para tanto, a metodologia da pesquisa utilizada foi a coleta de dados realizada por meio de questionário semiestruturado, contendo 11 perguntas. O questionário foi aplicado no próprio estabelecimento ao responsável pela administração do restaurante e aos funcionários que têm ligação direta com o estoque, totalizando 6 entrevistados, seguido de observação direta do local e da pesquisa bibliográfica para compor o referencial teórico deste trabalho. Os resultados apontaram que o estabelecimento precisa dar uma maior atenção ao controle de estoque, uma vez que os controles, que vinham sendo utilizados, não eram suficientes para trazer o retorno desejado do negócio.
Potentialets politik
Authors: Mikkelsen Henrik Hvenegaard
Published: May 2019

Denne artikel er baseret på et etnografisk studie blandt ældre borgere og sundhedspersonale på Møn og Sydsjælland. I de seneste år er social isolation og ensomhed blandt ældre blevet et kerneområde inden for diskussionen af folkesundhed i Danmark. Med udgangspunkt i denne observation, undersøger jeg, hvorfor netop ensomhed er blevet et centralt fokusområde for de danske sundhedsmyndigheder. Spørgsmålet er, hvordan ensomhed bliver opfattet i en tid, hvor ældres sundhed er genstand for stadig større opmærksomhed. Jeg knytter indsatserne over for ensomhed til en mere generel ’potentialets politik’, dvs. en fremherskende fortælling om sundhed i Danmark, som siger, at vi alle har potentialet for—samt en forpligtigelse til—ikke blot at opretholde vores sundhed, men også at engagere os socialt livet igennem.
Cambiar para renacer, renacer para volver a ser
Authors: Romà i Monfà Rosa
Published: May 2019

Rosa Romà, recientemente reelegida Decana del Col·legi de Publicitaris i Relacions Públiques de Catalunya, comparte su visión del sector de la comunicación y el marketing, y apunta una nueva etapa de la asociación profesional que preside, apostando por la innovación y la creatividad como elementos clave para diferenciar el sector dentro del panorama internacional.
Angiosperm phylogeny poster (APP) – Flowering plant systematics, 2019
Authors: Cole Theodor C H , Hilger Hartmut H , Stevens Peter
Published: May 2019

The Angiosperm Phylogeny Poster – Flowering Plant Systematics is an educational poster presenting an overview of the evolutionary relationships among flowering plants, based on APG IV/APweb and in this update chiefly following the topology of PPA ("Plastid Phylogenomic Angiosperm" see Li HT et al. 2019). The phylogenetic tree depicts the 64 orders and the majority of the 416 families, listing the main apo- and plesiomorphies as well as diagnostic and nondiagnostic anatomical, morphological, and phytochemical features for orders and higher ranks within the tree along with the number of families, genera, and species for each order. The intuitive color-coding facilitates memorization and teaching. The poster is now available in 25 languages (all downloadable from ResearchGate).
Lead isotope trends and sources in the atmosphere at an artificial wetland
Authors: Cong Ling , Zhai Jiexiu , Yan Guoxin , Liu Jiakai , Wu Yanan , Wang Yu , Zhang Zhenming , Zhang Mingxiang
Published: May 2019

With the rapid development of industry, studies on lead pollution in total suspended particulate matter (TSP) have received extensive attention. This paper analyzed the concentration and pollution sources of lead in the Cuihu Wetland in Beijing during the period of 2016–2017. The results show that the lead contents in TSP in the Cuihu Wetland were approximately equal in summer and spring, greater in winter, and greatest in autumn. The corresponding lead concentrations were 0.052 ng/m3, 0.053 ng/m3, 0.101 ng/m3, and 0.115 ng/m3, respectively. We compared the 206Pb/207Pb data with other materials to further understand the potential sources of atmospheric lead. The mean values of 206Pb/207Pb from spring to winter were 1.082, 1.098, 1.092, and 1.078, respectively. We found that the lead sources may be associated with coal burning, brake and tire wear, and vehicle exhaust emissions. We also calculated the enrichment factor values for the four seasons, and the values were all much greater than 10, indicating that the lead pollution is closely related to human activities.
Soil bacterial and fungal communities of six bahiagrass cultivars
Authors: Beule Lukas , Chen Ko-Hsuan , Hsu Chih-Ming , Mackowiak Cheryl , Dubeux Jr. Jose C.B. , Blount Ann , Liao Hui-Ling
Published: May 2019

Background

Cultivars of bahiagrass (Paspalum notatumFlüggé) are widely used for pasture in the Southeastern USA. Soil microbial communities are unexplored in bahiagrass and they may be cultivar-dependent, as previously proven for other grass species. Understanding the influence of cultivar selection on soil microbial communities is crucial as microbiome taxa have repeatedly been shown to be directly linked to plant performance.

Objectives

This study aimed to determine whether different bahiagrass cultivars interactively influence soil bacterial and fungal communities.

Methods

Six bahiagrass cultivars (‘Argentine’, ‘Pensacola’, ‘Sand Mountain’, ‘Tifton 9’, ‘TifQuik’, and ‘UF-Riata’) were grown in a randomized complete block design with four replicate plots of 4.6 × 1.8 m per cultivar in a Rhodic Kandiudults soil in Northwest Florida, USA. Three soil subsamples per replicate plot were randomly collected. Soil DNA was extracted and bacterial 16S ribosomal RNA and fungal ribosomal internal transcribed spacer 1 genes were amplified and sequenced with one Illumina Miseq Nano.

Results

The soil bacterial and fungal community across bahiagrass cultivars showed similarities with communities recovered from other grassland ecosystems. Few differences in community composition and diversity of soil bacteria among cultivars were detected; none were detected for soil fungi. The relative abundance of sequences assigned to nitrite-oxidizingNitrospirawas greater under ‘Sand Mountain’ than ‘UF-Riata’. Indicator species analysis revealed that several bacterial and fungal indicators associated with either a single cultivar or a combination of cultivars are likely to be plant pathogens or antagonists.

Conclusions

Our results suggest a low impact of plant cultivar choice on the soil bacterial community composition, whereas the soil fungal community was unaffected. Shifts in the relative abundance ofNitrospiramembers in response to cultivar choice may have implications for soil N dynamics. The cultivars associated with presumptive plant pathogens or antagonists indicates that the ability of bahiagrass to control plant pathogens may be cultivar-dependent, however, physiological studies on plant-microbe interactions are required to confirm this presumption. We therefore suggest that future studies should explore the potential of different bahiagrass cultivars on plant pathogen control, particularly in sod-based crop rotation.
Evaluation of Grain Yield of Two Varieties of Cowpea (Vigna unguiculata) Subjected to Four Agricultural Practices in Gùrué District, Mozambique
Authors: António Germias Horácio , Bofana José , Gimo Francisco , Cipriano Sueco Albino
Published: May 2019

To evaluate the effect of four agricultural practices on grain yield, two varieties (IT-16 and IT-18) of cowpeas were tested in the agricultural year 2016/2017 an experimental field where the following agricultural practices were tested: tillage, tillage + mulch, zero tillage and zero tillage + mulch. The randomized complete blocks design, a scheme consisting of two factors: agronomic practices and varieties was used. The plant height, number of pods per plant, weight of 100 seeds and grain yield in kg ha-1 were considered as parameters for analysis. From the results, it was concluded that for the yield of grain of different varieties under study, the variety IT-18 subjected to zero tillage + mulch and the variety IT-16 subjected to tillage had better performance achieving 2600.00 kg ha-1 and 1725.00 kg ha-1 respectively; therefore, recommended to the farmers.
California’s Visionary Tobacco Bill—Will the FDA Follow?
Authors: Jordt Sven E. , Jabba Sairam V.
Published: December 2024

This Viewpoint discusses California’s new law that will further strengthen tobacco control and whether the FDA and other states will follow California’s example.
Characterizing Services Advertised on Crisis Pregnancy Center Websites
Authors: Desai Karan S. , Keene Hollie , Dredze Mark , Smith Davey M. , Ayers John W.
Published: December 2024

This cross-sectional study assesses crisis pregnancy center websites to characterize the US states where they operate and the services that they advertise.
Dementia Incidence in Quebec Over 20 Years
Authors: Godard-Sebillotte Claire , Navani Sanjna , Rochette Louis , Massamba Victoria , Pelletier Éric , Kröger Edeltraut , Vedel Isabelle
Published: December 2024

This cross-sectional study examines the incidence of dementia from 2003 to 2023 in Quebec, Canada.
β-Blocker Use and Delayed Onset and Progression of Huntington Disease
Authors: Schultz Jordan L. , Ogilvie Amy C. , Harshman Lyndsay A. , Nopoulos Peg C.
Published: December 2024

Importance

Huntington disease (HD) is characterized by motor, cognitive, and psychiatric decline. β-Blockers may play a therapeutic role by decreasing enhanced sympathetic tone in HD.

Objective

To evaluate the impact of β-blockers on the timing of motor diagnosis onset and progression of HD symptoms.

Design, Setting, and Participants

This observational, longitudinal multicenter study used the Enroll-HD platform database (initiated September 2011 to present), including propensity score–matched cohorts of patients with premanifest HD (preHD) and early motor-manifest HD (mmHD) who were either users or nonusers of β-blockers. Participants included patients with genetically confirmed preHD (n = 4683 eligible participants) or mmHD (n = 3024 eligible participants) who were taking a β-blocker and were matched to similar non–β-blocker users.

Exposure

Uninterrupted use of a β-blocker for more than 1 year.

Main Outcomes and Measures

For PreHD: risk of receiving a motor diagnosis of HD over time. For mmHD: progression rate of total motor score, total functional capacity score, and the symbol digit modalities test. Post hoc analyses were performed to test additional clarifying hypotheses after the primary analyses were completed.

Results

This study included 174 preHD β-blocker users (59 males; 115 females) with a mean age of 46.4 (SD, 13.1) years and a mean cytosine-adenine guanine repeat length of 41.1 (SD, 2.4) who were well matched to 174 preHD non–β-blocker users. The preHD β-blocker users showed a statistically significant reduction in the annualized hazard of receiving a motor diagnosis compared with nonusers (n = 174) (hazard ratio, 0.66; 95% CI, 0.46-0.94; P = .02). There were 149 mmHD β-blocker users (86 males; 60 females) with a mean age of 58.9 (SD, 11.3) years and a mean cytosine-adenine guanine repeat length of 42.0 (SD, 2.3) matched to 149 mmHD non–β-blocker users. The β-blocker users had a slower mean annualized worsening in total motor score (mean difference [MD], −0.45; 95% CI, −0.85 to −0.06; q = 0.025), total functional capacity score (MD, 0.10; 95% CI, 0.02-0.18; q = 0.025), and symbol digit modalities test (MD, 0.33; 95% CI, 0.10-0.56; q = 0.017) compared with matched nonusers.

Conclusions and Relevance

In this study, β-blocker use was associated with delayed motor onset in preHD and reduced the rate of worsening of symptoms in mmHD. These findings demonstrated that β-blockers may have a therapeutic role in HD but further studies are required.
Lens Antennas
Authors: Malherbe Johannes A. G.
Published: December 2024

Lenses can be employed to act as high‐gain scannable antennas. The optical principles that apply to lens antennas are discussed, as well as the materials used in the construction of lenses. The basic lens function is discussed, and examples given of simple planoconvex and planoconcave lenses, together with the equations that describe the lens surfaces. In order to reduce the lens size, lenses are zoned, and equations for lens zoning are given. Other lens parameters such as gain, sidelobe level, reflections, loss, and bandwidth are treated. Lens systems for scannable or multibeam antennas are described, and design and analysis procedures for Rotman lenses given. Other lenses discussed include Luneburg,R‐2R, integrated dielectric, and Fresnel zone lenses. Physical construction methods for Rotman, Luneburg, and Fresnel zone plate lenses are discussed. This includes three‐dimensional (3D) printing and use of metamaterials.
Radar Antennas
Authors: Li Long , Xu Peng , Han Jiaqi , Feng Qiang , Cui Tie J.
Published: December 2024

The radar antenna plays an important role in the radar system, and the requirement of radar antenna performances and functions is varied with different radar types. The radar antenna forms a highly directive beam in both transmit and receive modes, which achieve accurate angular targets and resolve closely located targets, and this important feature of the radar antennas can be quantitatively expressed in terms of the beamwidth, gain, and sidelobes. Besides, the functions of radar antennas can be classified into beam scanning (search or surveillance target) and target tracking. In the increasingly complex electromagnetic (EM) world, digital coding and programmable metamaterials and metasurfaces have been enabling commercial opportunities with a broad impact on radars and wireless communications. Because the subject of radar antennas is very extensive, in this chapter, only selected types and performances of radar antennas are discussed and then four different antennas (reflector antennas, phased‐array antennas, space‐fed arrays, and metamaterial antennas) are summarized.
RADIO RECEPTION
Authors: Zvonar Zoran
Published: December 2024

Multiple factors influence the radio system performance, including radio propagation, radio link design, radio receiver design, and radio network design. The focus of this section is on the key elements of the radio reception that are starting point for the radio system design.

Radio propagation addresses fundamentals of path loss prediction models, outdoor and indoor prediction models, and effects of environment and small‐scale variations resulting in multipath fading. The emphasis is on channel characterization and statistical propagation models. Radio link design part covers link budget and frequency planning. Section on man‐made noise and interference completes the list of external factors that influence radio performance. The aspects of radio receiver design include introduction to radio front‐end parameters, diversity techniques, modulation and coding, and interference suppression techniques.
WIRELESS COMMUNICATION SYSTEMS
Authors: Armada Ana G. , Gil Jiménez Víctor P. , Morales Céspedes Máximo , Chen Hu Kun
Published: December 2024

This chapter introduces wireless communications systems and explains the different products and standards related to wireless communications. The chapter is divided into five main sections.

A brief introduction offers a perspective on the evolution of wireless communications systems and introduces a useful classification. After this introduction, an explanation of basic concepts and fundamentals of the different wireless products, followed by a presentation of the related technology the related technology.

The introduction and the basic concepts showed make it easy to understand the presentation of the most important wireless products and related standards are detailed: cellular, cordless, trunking, paging, wireless local‐area network (WLAN), wireless metropolitan‐area network (WMAN), and wireless personal‐area network (WPAN) systems.

Finally, a brief vision of the future evolution of wireless is disclosed, introducing advanced technologies and applications such as massive multiple input–multiple output (MIMO), light‐fidelity (LiFi), drones, and Internet of Things (IoT), and of actual research toward the next generation of mobile communications.
GYROTRONS
Authors: Ives Robert L.
Published: December 2024

The gyrotron is a vacuum tube capable of delivering high levels of radio‐frequency (RF) power at frequencies from several gigahertz to more than 500 GHz, which covers the microwave and millimeter‐wave band. Because of the structure of the RF fields in the cavity, the magnitude of the electric fields and the RF losses in the cavity walls are much lower in gyrotrons than in most microwave and millimeter‐wave vacuum tubes. As the RF frequency increases, it is not necessary to reduce the size of the cavity and output waveguide. For these reasons, the gyrotron is the principal RF device for delivering high levels of RF power at frequencies between 30 and 500 GHz.
STABILITY OF NONLINEAR SYSTEMS
Authors: Chen Guanrong
Published: December 2024

This chapter briefly presents the notion of stability of nonlinear systems in both continuous‐time and discrete‐time settings. Basic concepts and fundamental theorems of various system stabilities are introduced. These mainly include the important Lyapunov stability theory, along with some others particularly the orbital stability and the structural stability. The bounded‐input bounded‐output stability of maps is also discussed.
MONOPULSE TRACKING SYSTEMS
Authors: Sierra‐Pérez Manuel
Published: December 2024

Since its first conception at the end of World War II, the monopulse principle has become the most extended way to get accurate information about the target angular position in radar systems. Both tracking radars and scan radars use this principle in the accurate determination of the angular deviation with respect to the antenna axis (OBA, off‐boresight angle). Now, not only radar but any radio communication systems that need to orientate a narrow beam antenna to the transmitter use monopulse tracking systems. Satellite or deep space sound communications use this kind of system to secure links with very narrow beam antennas. Identification friend and foe (IFF) military systems use this principle to get narrow beam information links.

In this paper, the main characteristics of a monopulse tracking system are presented. First, a comparison to other angular detection tracking system is done to give the advantages of the monopulse. A brief description of the monopulse principle is introduced and a more extended description of antennas to obtain the main diagrams and monopulse processors to get the error signals are presented in the third and fourth sections.
VARIABLE‐FREQUENCY OSCILLATORS
Authors: Gutierrez Germán
Published: December 2024

Oscillators are abundant around us. Most oscillators are of two basic kinds: sinusoidal and relaxation. This chapter covers the main topologies for all popular oscillators and the ways to make their frequency of oscillation variable. The description is independent of frequency and can be applied from very‐low‐frequency to microwave oscillators. Mechanical examples give a very simple explanation for the mechanism of oscillators and the concept of resonance.

An
oscillator
is defined as anything that swings back and forth like a pendulum (vibrates) or travels back and forth between two points. An
electronic oscillator
is a device used for producing alternating current (e.g., a radio frequency or audio frequency generator).
Frequency
is the number of times that a periodic function repeats the same sequence of values during a unit of time or the number of complete oscillations of a wave per second.

Oscillators are abundant all around us: light, sound, the rotation of the Earth, electric AC power, heartbeats, musical instruments, motors, microprocessor clocks, etc. Some of these oscillatory systems have variable frequencies, and some have fixed frequency. We will first describe all the different types of electronic oscillators to appreciate what determines their operating frequency and how it can be varied.
SILICON MILLIMETER‐WAVE PHASED ARRAYS
Authors: Lee Wooram , Sadhu Bodhisatwa
Published: December 2024

Millimeter‐wave technology, with its large available bandwidth, promises many new wireless applications, from cellular communications to automotive radar for self‐driving vehicles. The silicon integration of mmWave and phased array technology has opened the door for large‐scale deployment of such systems. This chapter provides an overview tutorial of silicon‐based millimeter‐wave phased arrays and key building blocks.
Efficient and Stable Perovskite Solar Cells with a Multifunctional Spiro‐Based Hole Transport Material
Authors: Liu Xuepeng , Zhang Xianfu , Zhou Ying , Dai Weiqing , Chen Jianlin , Syzgantseva Olga A. , Syzgantseva Maria A. , Li Botong , Ghadari Rahim , Han Mingyuan , Du Weilun , Shao Zhipeng , Wang Qian , Dai Songyuan , Nazeeruddin Mohammad Khaja , Ding Yong
Published: December 2024

The widely used spiro‐OMeTAD exhibits moderate interaction with the perovskite layer, which does not decrease the defect on the perovskite surface, thus limiting the photoelectric performance of perovskite solar cells. In this work, the spiro‐OMeTAD structure is functionalized with chlorine (Cl), resulting in a new material labeled spiro‐mCl, which interacts more effectively with the perovskite and passivating interface defects. In addition, the strong electronegativity of Cl lowers the Highest Occupied Molecular Orbitals (HOMO) energy level of spiro‐mCl, resulting in a better match with the valence band of perovskite. Additionally, the asymmetry introduced by Cl enhances the hole mobility and increases the glass transition temperature of spiro‐mCl. As a result, the device incorporating spiro‐mCl achieved an open‐circuit voltage of 1.16 V and a remarkable power conversion efficiency of 25.26% (certified at 24.88%), marking it as one of the highest‐performing spirobifluorene‐based HTMs in PSCs. Importantly, this device also demonstrated significantly improved operational stability compared to the one utilizing spiro‐OMeTAD.
High‐Performance and Scalable Organosilicon Membranes for Energy‐Efficient Alcohol Purification
Authors: Zhu Tengyang , Shen Dongchen , Dong Jiayu , Liu Huan , Xia Qing , Li Song , Shao Lu , Wang Yan
Published: December 2024

The production of bio‐alcohol is increasingly gaining international attention due to its potential as a viable alternative to fossil fuels and its ability to mitigate carbon dioxide emissions. However, the cost of bio‐alcohol production is almost double that of fossil fuels, primarily because of the low yield of the purification process. Herein, a high‐performance and scalable organosilicon membrane with high chain flexibility and controllable crosslinking density is developed for energy‐efficient alcohol purification. The synthesized organosilicon membrane achieves an ultrahigh total flux (5.8 kg·m−2·h−1) with a comparable separation factor (8.7) for ethanol/water separation, outperforming most state‐of‐the‐art polymer‐based membranes. Integrated experiments and molecular dynamics simulations confirm that the ultrafast alcohol permeation of the membrane originates from its high chain flexibility, large fractional free volume, and weak interactions between feed molecules and membranes. The universal applicability of the low‐crosslinking mechanism for the formation of high‐performance organosilicon membranes is also validated. Moreover, its high efficiency and scalability in membrane production, along with the stability of the casting solution, offer promising prospects for industrial applications.
A Mechanoluminescence‐Based Stress Sensing Hydrogel for Intelligent Artificial Ligament
Authors: Yan Chunmei , He Xiao , Yu Bo , Zhou Bo , Fang Shaofan , Xu Jia , Liu Bin , Wang Zhaofeng
Published: December 2024

Robust and biocompatible hydrogels are recognized as promising biomimetic soft materials to improve human life quality. To ensure their stable, reliable, and safe service, the hydrogels are further required to have non‐contact and wireless stress sensing ability. Herein, a mechanoluminescence (ML) based micellar hydrogel is developed, in which the surface‐modified BaSi2O2N2: Eu2+ (M‐BSON) particles are chemically incorporated into the cross‐linked polyacrylamide/polymethyl acrylate (PAM/PMA) network structure. Because of the interactions between the M‐BSON particles and the PMA micelles, the as‐fabricated composite hydrogel exhibits enhanced mechanical properties with a mechanical strength of 2.73 MPa and a toughness of 3.40 MJ m−3, respectively. The chemical wrapping of the M‐BSON particles by the hydrophobic PMA micelles further protects the ML properties from water quenching, leading to remarkable stress‐induced luminescence under the water environment of hydrogel. Because of its desirable mechanical performance, attractive stress‐light responsiveness, and good biocompatibility, the M‐BSON incorporated hydrogel has the potential to be applied as an intelligent artificial ligament for stress self‐monitoring and failure warning. This work addresses the inhomogeneous dispersion and water quenching issues of the ML particles in hydrogel structure, which significantly promote ML applications in bionic engineering.
3D Printing of Proteins Via Temperature‐Dependent Amyloid Aggregation
Authors: Fu Chengyu , Pang Yanyun , Zhang Jinrui , Zhou Xingyu , Liu Yongchun , Li Min , Song Jinhua , Gao Yingtao , Wang Zhengge , Hu Bowen , Ji Wenrui , Hui Ziling , Wang Jinglin , Ma Jianing , Huang Zhaofang , Zhang Xu , Zhao Jian , Yang Peng
Published: December 2024

3D printing of protein materials for creating bioactive scaffolds has attracted significant interest. However, achieving controllable and stable printing while replicating the ordered structure found in natural protein materials remains a key challenge. Herein, a universally applicable temperature‐dependent protein aggregation (TPA) strategy is reported to manipulate the unfolding, relaxation, and reorganization of protein chains to enable the 3D printing of amyloid‐like proteins. The disruption of internal disulfide bonds induces the unfolding and relaxation of protein, leading to the formation of an amorphous protein sol through chain entanglement as primary cross‐linking points. These relaxed protein chains further aggregate through conformational transition to initiate amyloid‐like protein aggregation rich in β‐sheet structures at high temperature, resulting in a protein gel with β‐sheet nanocrystals serving as secondary cross‐linking points. This gel facilitates the stable and precise extrusion‐based 3D printing of proteinaceous scaffolds with a hierarchically ordered structure. The biomedical potential of this 3D‐printed protein scaffold is preliminarily validated through its biomineralization capability and following application in bone tissue regeneration using rat skull defect models. This strategy demonstrates a facile approach for the controllable structural aggregation of proteins in vitro and holds great potential in the field of protein‐based scaffolds.
Green Engineering of Silicon and Titanium Dioxide Architectures and Realizing Downstream Applications
Authors: Dirkzwager Adriaan , Mallee Lloyd , Groeneveld Tim , Quayson Essi B. , Qumber Mohammed Al , van Dongen Teresa , McMillan Duncan G. G.
Published: December 2024

Biomineralization has long been a source of inspiration and frustration for researchers in a wide variety of disciplines from ecologists and dental practitioners to materials scientists. An amazing variety of organisms have the capacity to produce inorganic mineral complexes through biomineralization. In this context, different organisms use proteins, peptides, and polysaccharides as templates to control the nucleation, growth, and morphology of structures containing minerals and metals. Due to lack of clarity in the field, distinctions are provided between the various biomineralization processes as Type I, II, and III biomineralization. Synthetic biomineralization is an emerging field in which these processes are applied to unnatural substrates to create useful inorganic materials with applications in a variety of fields. A comprehensive overview of silica and titanium oxide biomineralization is given, covering the major achievements this sub‐field has attained since its emergence. The ground‐breaking discoveries are focused based on the templating agent used and the mechanisms that are proposed in the field are discussed. Synthetic biomineralization are led, which are more recently demonstrated to have feasible applications in energy, electronics, construction, and biotechnology. These possibilities are discussed alongside prospects based on the current trend of research in the field.
Insight into Hydrovoltaic Technology: from Mechanism to Applications
Authors: Gu Chen , Luo Yixiang , Ji Huachao , Wang Shiyan , Huang BaoYu , Zhu Xianjun , Wang Longlu
Published: December 2024

Water encompasses vast quantities of energy in diverse forms, yet this energy is rarely exploited. Hydrovoltaic technology, as an emergent clean energy generation technology, has garnered extensive attention in recent years. Distinct from conventional hydroelectric power generation, hydrovoltaic technology ingeniously employs the interaction between functional materials and water, and achieves the direct conversion of water energy into electrical energy. This review initially delineates the mechanism of hydrovoltaic technology and deliberate on the various materials currently employed for hydroelectric power generation. Subsequently, experimental advancements in power generation from water droplets, water evaporation, and moisture are summarized to demonstrate the relevance of their fundamental mechanisms and their potential for harvesting energy from the water cycle. This work further expounds on the potential device applications of hydrovoltaic technology and proposes prospects for the development of emerging technologies.
A New Strategy for Photo‐Electrochemical Reduction of Carbon Dioxide Using a Carbazole‐BODIPY Based Metal‐Free Catalyst
Authors: Özdemir Mücahit , Uluçay Sude , Altınışık Sinem , Köksoy Baybars , Yalçın Bahattin , Koyuncu Sermet
Published: December 2024

In this study, a cross‐linked boron dipyrromethene (BODIPY) photocatalyst containing a carbazole donor group designed for photoelectrocatalytic carbon dioxide (CO2) reduction is synthesized and characterized. The BODIPY‐based system, coated onto a platinum surface, is evaluated for its electrochemical and photocatalytic performance under light illumination. Cyclic voltammetry (CV) and chronoamperometry measurements reveals enhanced photocurrent responses, confirming the catalyst's ability to effectively drive CO2 reduction. Gas chromatography/mass spectrometry (GC‐MS) analysis identifies the formation of ethanol (C2H5OH) as a major reaction product, showing that its yield increased with extended reaction times. Additionally, the photocatalyst demonstrates remarkable performance with significantly increasing turnover numbers (TON) and turnover frequencies (TOF) over time, indicating stable and sustained catalytic activity. With a Faradaic efficiency of 34.79% at a potential of ‐1.15 V, this BODIPY system exhibits both high activity and long‐term stability. The combination of efficient electron transfer and visible light absorption by the carbazole‐BODIPY donor‐acceptor structure positions this system as a highly promising candidate for sustainable CO2 conversion applications.
Switchable Radical Polymerization of α‐Olefins via Remote Hydrogen Atom or Group Transfer for Enhanced Battery Performance
Authors: Song Silin , Wang Shuo , Wang Ziqiang , Sun Hao , Wang Xianjin , Zhu Chen
Published: December 2024

Introducing polar groups into non‐polar polyolefins can significantly enhance the important properties of materials. However, producing polyolefin backbones consisting of polar blocks remains elusive, due to the substantial difference of reactivity ratios between polar and non‐polar olefin monomers in radical polymerization or the poisoning of transition‐metal catalysts by polar groups in coordination polymerization. Herein we present a practical way for the preparation of polyethylene‐based polymers with distinct polar groups by radical polymerization of α‐olefins. A strategy of switchable remote hydrogen atom or group transfer is devised, leading to a diverse range of AAB or ABC sequence‐defined carbon‐chain polyolefins. The utility of these polymers is demonstrated by using poly(ethyl 2‐cyanohept‐6‐enoate) (P2) as an interphase layer material in anode‐free Li metal battery, which effectively improves the cycling stability of the battery and indicates its potential in energy storage applications.