bluuebunny/crossref_metadata_2025 huggingface dataset:
Usages du vélo et rapports aux espaces publics des enfants : permanence de la division par sexe dans un dispositif d’apprentissage dans un quartier populaire à Strasbourg
Authors: Vieille Marchiset Gilles , Knobé Sandrine , Edzard Enno , Piombini Arnaud , Enaux Christophe
Published: May 2019

Cadre de la recherche : Dans les quartiers prioritaires de la Politique de la Ville en France, les activités physiques, qu’elles soient effectuées dans un cadre de déplacement ou de loisirs, restent en retrait par rapport au territoire français dans son ensemble. Si de multiples travaux analysent les activités physiques et sportives chez les jeunes, voire les adultes, les pratiques des enfants demeurent un point aveugle. Les enfances pauvres méritent pourtant un regard spécifique, particulièrement leurs rapports à l’espace public. Dans cette optique, la littérature scientifique insiste sur les mobilités indépendantes et sur les contraintes familiales, notamment chez les filles.

Objectifs : Il s’agit d’interroger les rapports sexués aux espaces publics dans les quartiers populaires à partir des usages du vélo d’enfants de 9 et 10 ans.

Méthodologie : Une équipe de sociologues et de géographes a suivi six classes de CM1 dans trois écoles primaires d’un quartier prioritaire de la Politique de la Ville à Strasbourg. Ces enfants ont bénéficié, pour deux d’entre elles, d’une formation spécifique, d’une part, par des éducateurs sportifs municipaux, et, d’autre part, par des formateurs en sécurité routière. La troisième école fait office de groupe témoin. Des questionnaires ad hoc ont été transmis dans chaque école, avant et après les cycles d’apprentissage du vélo, pour étudier l’évolution de leur niveau technique, de leurs usages du vélo dans le quartier et dans la ville, de leurs relations familiales et amicales nouées autour du vélo.

Résultats : Les résultats mettent en avant une différenciation sexuée, nette et persistante, en termes de contrôle du vélo, d’aisance technique dans et hors du quartier et surtout de poids de socialisations distinctes au risque et des contraintes familiales liées à la division par sexe.

Conclusion : Dès lors persistent, pour les enfants de ce quartier, des usages singuliers de l’espace public à vélo, liés principalement aux configurations relationnelles sexuées dans les familles populaires.

Contribution : Cette étude amène à questionner les méthodes d’apprentissage du vélo pour identifier les précautions à prendre pour favoriser les usages du vélo des garçons et des filles dans l’espace public. Il est alors conseiller de mobiliser les familles pour favoriser le vélo pour tous, particulièrement dans les quartiers socialement défavorisés.
Sur le chemin de l’école : perceptions de parents et d’enfants du primaire face au risque routier lors de la mise en place d’un Trottibus au Québec
Authors: Godillon Sylvanie , Cloutier Marie-Soleil
Published: May 2019

Cadre de la recherche : Dans les pays occidentaux, la marche pour se rendre à l’école est en forte diminution depuis la fin des années 1990. Cette diminution des déplacements à pied modifie le rapport des enfants aux espaces publics. Pour enrayer la diminution de la marche vers l’école, les Pédibus sont un programme d’incitation à la marche vers l’école sous la forme de l’organisation d’un ramassage scolaire pédestre sous la supervision d’un adulte.

Objectifs : Ces programmes ont fait l’objet d’évaluations, mais peu de recherches ont ciblé les différenciations des perceptions des parents et des enfants. L’objectif de cet article est d’analyser les différences de perceptions entre les parents et les enfants sur le risque routier lors de la mise en place d’un Pédibus afin d’interroger l’apprentissage de l’autonomie et le rapport aux espaces publics.

Méthodologie : Pour répondre à ces questionnements, nous nous appuyons sur une recherche concernant la mise en place de projets Trottibus, programme de Pédibus au Québec financé par la Société Canadienne du Cancer (SCC-Québec). Une enquête a été autoadministrée par Internet auprès de 189 parents et d’un de leurs enfants âgés de 5 à 11 ans avant ou au tout début de leur participation à un Trottibus.

Résultats : Les résultats montrent un plus grand sentiment de sécurité de la part des enfants lorsqu’ils marchent sur un espace sécurisé pour les piétons et une plus forte confiance dans les autres usagers quant au respect des piétons. Pour les parents, le Trottibus a des bienfaits éducatifs quant à l’apprentissage de la mobilité piétonne. Les enfants et les parents mettent en avant les dimensions de sociabilité de ce programme.

Conclusions : Les résultats permettent de mieux comprendre la familiarisation du trajet scolaire par les enfants et leurs perceptions de la sécurité routière sous divers scénarios (marcher sur le trottoir, traverser, jouer dans la rue, etc.) ainsi que de documenter les différences entre les attentes des parents et des enfants.

Contribution : L’accompagnement par les adultes interroge le rapport à la ville et l’acquisition de l’autonomie. Si les parents craignent de laisser leur enfant marcher seul pour un trajet connu entre le domicile et l’école à l’âge où s’expérimente la mobilité autonome, les enfants risquent d’acquérir plus tardivement les compétences pour se déplacer en sécurité et expérimenter les espaces publics des villes.
La reconquête de Beyrouth pour les enfants et les adolescents au prisme des infrastructures scolaires
Authors: Azzam Cynthia
Published: May 2019

Cadre de la recherche : Bien qu’elle connaisse le Bois des Pins (récemment rouvert au public), la ville de Beyrouth manque cruellement d’espaces publics. Les quelques rares places sont, pour la plupart, dégradées ; les petits espaces récréatifs dédiés aux enfants, bien peu nombreux. Cette ville, qui peu à peu se vide des jeunes couples (surtout avec l’élévation du prix foncier), ne s’intéresse guère aux enfants ou aux adolescents, mais cherche avant tout à attirer le jeune public dans ses quartiers branchés ou à séduire les touristes par la reconstruction du centre-ville.

Objectifs : Le présent article n’a pas comme objectif de s’épancher sur les maux de cette société dont les origines remontent à des siècles, mais plutôt d’analyser « la ville comme le lieu où s’inventent les solutions ». Nous nous demandons alors : pourquoi ne pas réinventer l’usage des écoles (qui ne servent que quelques heures durant la journée) pour en faire des espaces récréatifs l’après-midi et durant les vacances estivales ?

Méthodologie : En nous fondant sur les résultats d’une recherche doctorale portant sur l’architecture scolaire au Liban, nous avons identifié les attentes des usagers en matière d’espaces urbains. Nous privilégions dans ce travail une méthode mixte : qualitative (à travers des entretiens semi-directifs réalisés avec les acteurs du secteur éducatif) et quantitative (portant sur un modèle de cas multiples).

Résultats : Les avis recueillis des directeurs, des parents et des élèves, bien que ces derniers fussent parfois réticents, paraissent s’accorder avec la volonté de faire place aux jeunes dans la ville de demain. Mais le partage des espaces scolaires avec la ville pose la question de la sécurité, de la détérioration et du maintien de la propreté de ces infrastructures.

Conclusions : Rendre la ville aux enfants et aux adolescents impliquera donc non seulement des modifications physiques dans la ville mais aussi un changement des habitudes et des mentalités des habitants et des décideurs locaux.

Contribution : Cet article cherche à penser « autrement » le milieu scolaire urbain afin de rendre aux jeunes des espaces qui leur reviennent de droit.
Des sculptures récréatives des années 1970 aux aires de jeux contemporaines à la Grande Borne : jouer n’est pas joué
Authors: Fanny Delaunay
Published: May 2019

Cadre de la recherche : La question des pratiques des espaces ludiques au sein des espaces publics est souvent posée depuis un angle de la sociologie ou de la psychologie environnementale mais assez peu par une entrée urbaine ou architecturale.

Objectifs : Cet article s’interroge sur le processus de normalisation des espaces publics pour enfants dédiés aux pratiques ludiques. L’enquête prend comme cas d’étude les espaces historiques de jeux et les nouvelles aires de jeux de la Grande Borne. La conception de ce grand ensemble emblématique des opérations d’habitat social réalisées en France dans les années 1970 parie sur les rapports électifs de l’enfant aux espaces urbains, réalisant ainsi une cité où il en serait le prince (Aillaud, 1972).

Méthodologie : Vingt-et-un entretiens ont été réalisés avec des enfants dans le cadre d’une observation participante au sein de structures péri-scolaires et onze avec les acteurs porteurs des projets d’aménagement. Les propos recueillis ont été confrontés à une enquête archivistique et d’observation.

Résultats : Aujourd’hui en rénovation, les espaces historiques de jeux font l’objet d’une normalisation. Les processus à l’œuvre mettent en évidence la transformation des représentations de l’enfant dans les espaces de jeux et de ses usages depuis le point de vue des concepteurs et des gestionnaires des lieux. L’industrialisation des espaces publics ludiques sous-tend une politique normative aussi bien des pratiques que des formes de l’espace dans l’optique de minimiser tous les dangers possibles.

Conclusions : Les conclusions de recherche pointent que le rôle du concepteur n’est plus d’accompagner les enfants dans leur processus d’apprentissage en vue de favoriser leur émancipation, comme l’ambitionnait Émile Aillaud, mais de l’inscrire dans une démarche de socialisation qui vise à minimiser les aléas encourus aussi bien par les enfants que par les concepteurs ou les gestionnaires, interrogeant alors le potentiel de jeu des opérations et leurs rôles socio-urbains « cachés ».

Contribution : Le questionnement sur le sens socio-urbain des espaces ludiques dédiés aux enfants s’inscrit dans le sillage des travaux des new social studies of childhood (Holloway et Valentine, 2000) visant à rendre compte des nouvelles visibilités de l’enfance dans l’espace public.
A Socio-technical Systems Approach to Design and Support Systems Thinking in Cybersecurity and Risk Management Education
Authors: Zoto Erjon , Kianpour Mazaher , Kowalski Stewart , Lopez-Rojas Edgar
Published: May 2019

Cybersecurity decisions are made across a range of social, technical, economic, regulatory and political domains. There is a gap between what companies and institutions plan to do while developing their internal IS-related policies and what should be done according to a multi-stakeholder system perspective in this area. Our task as researchers is to bridge this gap by offering potential solutions. The aim of our work is to promote the usage of the socio-technical systems (STS) approach to support the emerging role of systems thinking in cybersecurity education, using simulation as a supporting tool for learning. Meanwhile, new trends in cybersecurity curricula suggest an important shift toward new thinking approaches such as adversarial and systems thinking. We explored individuals’ adversarial and systems thinking skills in an open agent-based simulated environment and subsequently assessed the impact based on a participant survey. We discuss these results and point to directions for further investigation. The second contribution of the article is the provision of a tool for developing target users’ skills in making quantitative risk decisions and giving them a deeper understanding of the importance and use of key indices in the cyber risk management process.
МЕРЕЊЕ И УНАПРЕЂЕЊЕ ИНДИКАТОРА КЉУЧНИХ ПЕРФОРМАНСИ У САВРЕМЕНИМ КОМПАНИЈАМА
Authors: Дајић Милан , Тодић Марко
Published: May 2019

У турбулентним условима пословања савремени системи мерењаперформанси пружају квалитетније информације менаџменту у процесуодлучивања. Преко кључних индикатора перформанси мери се остварењевизије, стратегије и циљева предузећа. Када компанија бира кључне индикатореперформанси треба да води рачуна да ти показатељи обезбеде информације којеће бити мерљиве, поуздане, реалне и употребљиве за примену одговарајућихкорективних мера када перформансе нису усаглашене са циљевимаорганизације. Неопходно је адекватну пажњу посветити унапређењу кључнихиндикатора перформанси, а све са циљем прилагођавања и постизања бољихрезултата у савременим променљивим условима пословања. Постоји одређениброј приступа за развој кључних индикатора перформанси, а предузећа треба да,у складу са послом којим се баве, идентификују приступе који би билинајрелевантнији за њих. Основна тежња савремених организација јеусклађивање кључних индикатора перформанси са модификованим условимапословања, што је и основа за унапређење истих.
OSNOVNI PRINCIPI TERAPIJE MASTITISA KRAVA
Authors: RADINOVIĆ Miodrag , DAVIDOV Ivana , KOVAČEVIĆ Zorana , STOJANOVIĆ Dragica , GALFI Annamaria , ERDELJAN Mihajlo
Published: May 2019

Mastitisi predstavljaju, u savremenom govedarstvu, jedan od najvažnijihzdravstvenih problema kod muznih krava. Pored zdravstvenog aspekta i očiglednog uticaja nadobrobit životinja mastitisi se ubrajaju u najveće finansijske troškove na farmi krava zbog troškovasame terapije i odbačenog mleka zbog karence kao i trajno smanjene proizvodnje mleka ili potpunogprekida laktacije kod teških formi mastisa. Ovome treba dodati i trošak nastao zbog mogućihuginuća ili preranog izlučenja krava iz proizvodnje. Postupak terapije mastitisa i ishod lečenja zaviseod forme zapaljenja vimena, stepena alteracije tkiva i na kraju od vremena početka terapije i primeneadekvatnog preparata ili adekvatnog postupka. Ishod terapije može biti potpuna restitucijaparenhima, oporavak funkcije ili propadanje žlezdanog parenhima i popunjavanje vezivnim tkivom.U današnje vreme, u uslovima intenzivne proizvodnje mleka terapija mastitisa je samo deo programakontrole mastitisa koji u prvi plan stavljaju prevenciju mastitisa. U slučaju pak pojave kliničke formemastitisa neophodno je pristupiti terapiji u laktaciji.
MICROBIOLOGICAL PURITY TESTING IN FOOD PRODUCTION AND MARKETING
Authors: GOLIĆ Bojan , ILIĆ Tanja , KALABA Vesna , GOLIĆ Milijana , DELIĆ Slobodanka
Published: May 2019

The Rulebook on microbiological purity criteria prescribes the criteria of microbiologicalpurity and the frequency of control of equipment, devices, utensils, work surfaces, work clothes andworkers' hands in food production and marketing as well as in facilities and means of transport thatcome in contact with food in which there is a risk of occurrence and the spread of infectious diseases.Food facilities, means of transport, items, accessories and equipment that come in contact with foodmust be regularly cleaned and disinfected to avoid any risk of contamination, and food and staffmust be under regular supervision. Food handling staff must maintain a high level of personalhygiene and be trained in terms of food hygiene requirements. The aim of the study was to determinethe state of microbiological purity in food production and marketing in facilities and means oftransport that come into contact with food. As the test material we used swab samples from thesurfaces of equipment, devices, utensils, work surfaces, work clothes and workers' hands originatingfrom facilities for the production and marketing of food, restaurants and other catering facilitiesserving food, facilities in the field of education and social protection (facilities for accommodatingpersons) and means of transport that come into contact with food. A total of 3393 samples wereexamined in the course of self-control and official control during 2017. For microbiologicalexamination of swab samples, standard BAS ISO methods were used. The percent of swab samplesthat did not satisfy the Rulebook on the criteria of microbiological purity in 2017 was 5.20%. Inrelation to the total number of samples tested, 4.70% of the samples were unsatisfactory due to anincreased number of microorganisms, and 1.40% due to an increased number of enterobacteriaceae.Pathogenic microorganisms Salmonella spp. and Listeria monocytogenes are not detected in anyswab sample. The largest percent of unsatisfactory samples was in the category "hands of foodhandlers" and amounted to 7.30%
GIPC proteins negatively modulate Plexind1 signaling during vascular development
Authors: Carretero-Ortega Jorge , Chhangawala Zinal , Hunt Shane , Narvaez Carlos , Menéndez-González Javier , Gay Carl M , Zygmunt Tomasz , Li Xiaochun , Torres-Vázquez Jesús
Published: May 2019

Semaphorins (SEMAs) and their Plexin (PLXN) receptors are central regulators of metazoan cellular communication. SEMA-PLXND1 signaling plays important roles in cardiovascular, nervous, and immune system development, and cancer biology. However, little is known about the molecular mechanisms that modulate SEMA-PLXND1 signaling. As PLXND1 associates with GIPC family endocytic adaptors, we evaluated the requirement for the molecular determinants of their association and PLXND1’s vascular role. Zebrafish that endogenously express a Plxnd1 receptor with a predicted impairment in GIPC binding exhibit low penetrance angiogenesis deficits and antiangiogenic drug hypersensitivity. Moreover, gipc mutant fish show angiogenic impairments that are ameliorated by reducing Plxnd1 signaling. Finally, GIPC depletion potentiates SEMA-PLXND1 signaling in cultured endothelial cells. These findings expand the vascular roles of GIPCs beyond those of the Vascular Endothelial Growth Factor (VEGF)-dependent, proangiogenic GIPC1-Neuropilin 1 complex, recasting GIPCs as negative modulators of antiangiogenic PLXND1 signaling and suggest that PLXND1 trafficking shapes vascular development.
Cerebellar Purkinje cells control eye movements with a rapid rate code that is invariant to spike irregularity
Authors: Payne Hannah L , French Ranran L , Guo Christine C , Nguyen-Vu TD Barbara , Manninen Tiina , Raymond Jennifer L
Published: May 2019

The rate and temporal pattern of neural spiking each have the potential to influence computation. In the cerebellum, it has been hypothesized that the irregularity of interspike intervals in Purkinje cells affects their ability to transmit information to downstream neurons. Accordingly, during oculomotor behavior in mice and rhesus monkeys, mean irregularity of Purkinje cell spiking varied with mean eye velocity. However, moment-to-moment variations revealed a tight correlation between eye velocity and spike rate, with no additional information conveyed by spike irregularity. Moreover, when spike rate and irregularity were independently controlled using optogenetic stimulation, the eye movements elicited were well-described by a linear population rate code with 3–5 ms temporal precision. Biophysical and random-walk models identified biologically realistic parameter ranges that determine whether spike irregularity influences responses downstream. The results demonstrate cerebellar control of movements through a remarkably rapid rate code, with no evidence for an additional contribution of spike irregularity.
Multi-phosphorylation reaction and clustering tune Pom1 gradient mid-cell levels according to cell size
Authors: Gerganova Veneta , Floderer Charlotte , Archetti Anna , Michon Laetitia , Carlini Lina , Reichler Thais , Manley Suliana , Martin Sophie G
Published: May 2019

Protein concentration gradients pattern developing organisms and single cells. In Schizosaccharomyces pombe rod-shaped cells, Pom1 kinase forms gradients with maxima at cell poles. Pom1 controls the timing of mitotic entry by inhibiting Cdr2, which forms stable membrane-associated nodes at mid-cell. Pom1 gradients rely on membrane association regulated by a phosphorylation-dephosphorylation cycle and lateral diffusion modulated by clustering. Using quantitative PALM imaging, we find individual Pom1 molecules bind the membrane too transiently to diffuse from pole to mid-cell. Instead, we propose they exchange within longer lived clusters forming the functional gradient unit. An allelic series blocking auto-phosphorylation shows that multi-phosphorylation shapes and buffers the gradient to control mid-cell levels, which represent the critical Cdr2-regulating pool. TIRF imaging of this cortical pool demonstrates more Pom1 overlaps with Cdr2 in short than long cells, consistent with Pom1 inhibition of Cdr2 decreasing with cell growth. Thus, the gradients modulate Pom1 mid-cell levels according to cell size.
Examining the assumptions of heterogeneity-based management for promoting plant diversity in a disturbance-prone ecosystem
Authors: McGlinn Daniel J. , Palmer Michael W.
Published: May 2019

Background

Patch-burn management approaches attempt to increase overall landscape biodiversity by creating a mosaic of habitats using a patchy application of fire and grazing. We tested two assumptions of the patch-burn approach, namely that: (1) fire and grazing drive spatial patch differentiation in community structure and (2) species composition of patches change through time in response to disturbance.

Methods

We analyzed species cover data on 100 m2square quadrats from 128 sites located on a 1 × 1 km UTM grid in the grassland habitats of the Tallgrass Prairie Preserve. A total of 20 of these sites were annually sampled for 12 years. We examined how strongly changes in species richness and species composition correlated with changes in management variables relative to independent spatial and temporal drivers using multiple regression and direct ordination, respectively.

Results

Site effects, probably due to edaphic differences, explained the majority of variation in richness and composition. Interannual variation in fire and grazing management was relatively unimportant relative to inherent site and year drivers with respect to both richness and composition; however, the effects of fire and grazing variables were statistically significant and interpretable, and bison management was positively correlated with plant richness.

Conclusions

There was some support for the two assumptions of patch-burn management we examined; however, in situ spatial and temporal environmental heterogeneity played a much larger role than management in shaping both plant richness and composition. Our results suggest that fine-tuning the application of fire and grazing may not be critical for maintaining landscape scale plant diversity in disturbance-prone ecosystems.
Characterization of introgression from the teosinte Zea mays ssp. mexicana to Mexican highland maize
Authors: Gonzalez-Segovia Eric , Pérez-Limon Sergio , Cíntora-Martínez G. Carolina , Guerrero-Zavala Alejandro , Janzen Garrett M. , Hufford Matthew B. , Ross-Ibarra Jeffrey , Sawers Ruairidh J. H.
Published: May 2019

Background

The spread of maize cultivation to the highlands of central Mexico was accompanied by substantial introgression from the endemic wild teosinte Zea mays ssp. mexicana, prompting the hypothesis that the transfer of beneficial variation facilitated local adaptation.

Methods

We used whole-genome sequence data to map regions of Zea mays ssp. mexicana introgression in three Mexican highland maize individuals. We generated a genetic linkage map and performed Quantitative Trait Locus mapping in an F2 population derived from a cross between lowland and highland maize individuals.

Results

Introgression regions ranged in size from several hundred base pairs to Megabase-scale events. Gene density within introgression regions was comparable to the genome as a whole, and over 1,000 annotated genes were located within introgression events. Quantitative Trait Locus mapping identified a small number of loci linked to traits characteristic of Mexican highland maize.

Discussion

Although there was no strong evidence to associate quantitative trait loci with regions of introgression, we nonetheless identified many Mexican highland alleles of introgressed origin that carry potentially functional sequence variants. The impact of introgression on stress tolerance and yield in the highland environment remains to be fully characterized.
Prefrontal cortical activation measured by fNIRS during walking: effects of age, disease and secondary task
Authors: Pelicioni Paulo H.S. , Tijsma Mylou , Lord Stephen R. , Menant Jasmine
Published: May 2019

Background

Cognitive processes are required during walking to appropriately respond to environmental and task demands. There are now many studies that have used functional Near-Infrared Spectroscopy (fNIRS) to record brain activation to investigate neural bases of cognitive contributions in gait. The aim of this systematic review was to summarize the published research regarding Prefrontal cortical (PFC) activation patterns during simple and complex walking tasks in young adults, older adults and clinical groups with balance disorders using fNIRS. Our secondary aim was to evaluate each included study based on methodological reporting criteria important for good data quality.

Methods

We conducted searches in June 2018 using four databases: Embase, PubMed, Scopus and PsycINFO. The strategy search used was: (((((near infrared spectroscopy) OR functional near infrared spectroscopy) OR nirs) OR fnirs) AND (((gait) OR walking) OR locomotion) AND (((((young) OR adult) OR older) OR elderly) NOT children)) AND (((Brain) OR cortex) OR cortical) for our search. The papers included met the specific review criteria: (i) used fNIRS to measure PFC activation patterns; (ii) included walking tasks (simple and complex) and; (iii) assessed young people, older people and/or clinical groups with balance disorders.

Results

Thirty five (describing 75 brain activation comparisons) of the 308 studies retrieved through our search met the inclusion criteria. Based on 6 methodological reporting considerations, 20 were of high quality, 10 were of medium quality and 5 were of low quality. Eleven/20 comparisons in young people, 23/37 comparisons in older people and 15/18 comparisons in clinical groups reported increased PFC activation with increased walking task complexity. The majority of comparisons that used verbal fluency, counting backwards or secondary motor tasks reported increases in PFC activation (83%, 64% and 58% of these studies, respectively). In contrast, no studies found secondary visual tasks increased PFC activation.

Conclusion

Increased PFC activation was most common in studies that involved walks comprising secondary verbal fluency and arithmetic tasks. Clinical groups generally showed increased PFC activation irrespective of type of secondary task performed during walking which suggests these groups require more attentional resources for safe walking. Systematic review registration number: PROSPERO 2017 - CRD42017059501.
Phylogenomic analysis and revised classification of atypoid mygalomorph spiders (Araneae, Mygalomorphae), with notes on arachnid ultraconserved element loci
Authors: Hedin Marshal , Derkarabetian Shahan , Alfaro Adan , Ramírez Martín J. , Bond Jason E.
Published: May 2019

The atypoid mygalomorphs include spiders from three described families that build a diverse array of entrance web constructs, including funnel-and-sheet webs, purse webs, trapdoors, turrets and silken collars. Molecular phylogenetic analyses have generally supported the monophyly of Atypoidea, but prior studies have not sampled all relevant taxa. Here we generated a dataset of ultraconserved element loci for all described atypoid genera, including taxa (MecicobothriumandHexurella)key to understanding familial monophyly, divergence times, and patterns of entrance web evolution. We show that the conserved regions of the arachnid UCE probe set target exons, such that it should be possible to combine UCE and transcriptome datasets in arachnids. We also show that different UCE probes sometimes target the same protein, and under the matching parameters used here show that UCE alignments sometimes include non-orthologs. Using multiple curated phylogenomic matrices we recover a monophyletic Atypoidea, and reveal that the family Mecicobothriidae comprises four separate and divergent lineages. Fossil-calibrated divergence time analyses suggest ancient Triassic (or older) origins for several relictual atypoid lineages, with late Cretaceous/early Tertiary divergences within some genera indicating a high potential for cryptic species diversity. The ancestral entrance web construct for atypoids, and all mygalomorphs, is reconstructed as a funnel-and-sheet web.
Study the Space –Time Variations of Indus River Flow Propagation
Authors: Hassan Syed Ahmad , Ansari Muhammad Rashid Kamal
Published: May 2019

River flow is the most important geophysical process of the earth and its ecosystem. Being very unpredictable in nature, at several times its ensemble flow propagation along the network becomes hazardous flood, that causes enormous damage and loss. Pakistan is an agricultural country with one of the world’s largest Indus River system. The system undergoes great climatic, strong seasonal and inter-annual variability dominated by both monsoon and snow-glacier dynamics of the Himalayan and Karakoram regions. A better understanding of the variability may provide insight into the problems associated with unpredictable variations in river flow and their propagation. This paper is an attempt to enhance the current knowledge of the Indus River flow dynamics along the network. For this purpose linear and nonlinear methods of propagation analysis of the mean 10 daily river flow (TDF) are utilised. The linear and nonlinear schemes employ cross-correlation and the normalized average of cross-mutual information (MI) method respectively. The overall dominant mechanism of the system shows a linear behaviour, however, some stations demonstrate nonlinear propagation in the network. The results of these analyses may also provide the viability to study the behaviour of regional and global climatic parameters related to the type of information propagated.
Evaluation of Operational Performance and Economic Analysis of a Gas Turbine Power Plant: A Case Study of Ibom Power Station
Authors: Ubani N. O. , Ikebudu K. O.
Published: May 2019

This work evaluates the performance indicator of Ibom Power Plant as one of the Independent Power Producers (IPPs) in Nigeria. The operational performance and the economic analysis of the three gas turbines present there-GTG 1 (Model PG 6551B), GTG 2 (Model PG 6561B), and GTG3 (Model PG 9171E) with combined installed capacity of 190MW were investigated. The study showed that the average station load factor, average capacity utilization index and the average generation utilization index were about 42%, 51% and 46% respectively, which were low when compared with 70% as recommended by the Nigerian Electricity Regulatory Commission (NERC); while the average plant heat rate was found to be 12,659.60MJ/MWh which also tends to be higher than the 10,000MJ/MWh allowed by NERC. The average thermal efficiency and the average capacity factor gave a result of 28.44% and 19% respectively. The NERC’s Multi Year Tariff Order (MYTO) of N10.70 per KWh for generation companies’ was used in evaluating the company’s revenue with reference to the application of Net present value (NPV) and internal rate of return (IRR). Obviously, the cost of power generation can be reduced by improving capacity factor; running the power station at high load factor; increasing the efficiency of the power plant and proper maintenance plan to avoid breakdowns. An upward review of MYTO tariff to ensure economic viability of Nigerian Electricity Supply Industry was recommended.
Pharmacy Students’ Perception and Evaluation of Objective Structured Clinical Examination: Near East University Experience
Authors: Basgut Bilgen , Abdi Abdikarim Mohamed
Published: May 2019

Background: Pharmacy educators have always been desirous of the best methods for formative and summative evaluation of trainees. The Objective Structured Clinical Examination (OSCE) is an approach for student assessment in which aspects of clinical competence are evaluated in a comprehensive, consistent, and structured manner. Though recently become popular in pharmacy schools globally, its use in North Cyprus and Turkey pharmacy schools appears limited.

Objectives: To assess pharmacy students’ evaluation and overall perception of OSCE.

Methods: A cross-sectional survey was conducted on pharmacy students, who participated in the final OSCE examination in 2015-2016.The study sample consisted of fifth-year Pharmacy students who took the OSCE assessment during their studies. A24-item self-administered structured questionnaire was employed to obtain relevant data on OSCE evaluation in terms of content reliability and structure of the examination. Students’ responses were based on a 4-point Likert scales ranging from disagree to no comment. The data were analyzed using SPSS, version 22.

Results: Of 81 eligible students, 74 completed self- administered questionnaire representing 91.35% response rate. A total of 68(90.7%) students agreed that wide knowledge area and clinical skills were covered in the exam. Over 80% of the students saw that OSCE besides it provided them with an opportunity to learn real life scenario, it was well administered and run in the faculty and better organized compared to a previous pilot OSCE (68%). Around 77% of the students saw that 7 minutes time allocated per station was adequate, while a close percentage also agreed that standardized patients were competent in their role playing. Majority of students though they identify that OSCEs highlighted areas of weakness in their skills and knowledge but still disagree with incorporating OSCEs marks into final marks and thus prefer it as an formative assessment.

Conclusions: Students highly perceived the exam feeling that it is more resembles actual practice providing them with self-confidence, and more clearly their defects and what they need to improve regarding both skills and knowledge. They saw OSCEs as being a beneficial formative assessment that should not be included as marks into finals.
Gratings and Grating Antennas
Authors: Rodenbeck Christopher T. , Chang Kai
Published: November 2024

Agratingis an array of parallel obstructions separated from one another at a distance comparable to a wavelength. When an electromagnetic wave is incident up on a grating, it scatters to one or more specific angles determined by the spacing of the grating and the frequency of the wave. Since this effect is a diffraction phenomenon, gratings are often also referred to asdiffraction gratings.

One of the most important uses of the diffraction grating is as an antenna for millimeter‐wave through optical frequencies. This type of diffraction grating is the primary focus of this article. In integrated optics, grating antennas are used to couple power into and out of dielectric waveguides. For millimeter‐wave systems, grating antennas have received attention for several key advantages that they have in comparison with other conventional microwave antennas. They have low radiation losses, they are inexpensive and easy to fabricate, and they are planar. There is also considerable interest in using grating antennas to implement low‐cost beam steering at millimeter‐wave frequencies.

This article examines gratings and grating antennas in a series of five sections. Each of these sections is presented in such a way that it may be read independently from the others. An overview of the historical development of diffraction gratings is presented. The fundamental principles behind grating diffraction are explained in a manner suitable for those with an RF/microwave background. A clear design procedure for grating antennas is offered, along with an extensive reference list for those interested in further study. Some of the latest and most impressive applications of millimeter‐wave gratings are described. The article then concludes with a brief discussion of the future of this field.
Microstrip Antenna Arrays
Authors: Hall Peter S.
Published: November 2024

Microstrip antenna arrays offer low‐profile solutions to many antenna applications with potentially low cost. Their low profile comes about from the use of microstrip patch radiators fed by microstrip circuit‐based feed networks, or by using the naturally occurring radiation from the feed networks to form a beam. Both patches and microstrip feeds consist of metallic strips or shapes photoetched on one side of a grounded substrate and can be made using conventional photolithographic processes. The use of the microstrip transmission‐line medium, widely used in both hybrid and monolithic radiofrequency circuits, also gives rise to a unique potential for integration with active devices and radio front ends.

This article gives an overview of microstrip array architectures. These include parallel‐ and series‐fed arrays and also arrays formed by discontinuities in a microstrip line, such as the serpent and rampart lines. Other forms such as ultrawideband arrays, leaky‐wave arrays, multilayer arrays, sequentially rotated arrays, multibeam arrays, reflect arrays, and active integrated arrays are also described. The article concludes by describing the impact on array design of important factors such as accuracy in pattern synthesis, feed loss and radiation, and mutual coupling.
Notch Antennas
Authors: Lee Richard Q.
Published: November 2024

Notch antennas, also known as the tapered slot antennas (TSA), have been the topics of research for decades. TSA has demonstrated multioctave bandwidth, moderate gain (7–10 dB), and symmetricE‐ andH‐plane beam patterns and can be used for many different applications. This article summarizes the research activities on notch antennas over the since the early 1990s with emphasis on their most recent advances and applications. The article begins with some discussions on the design of single TSA, then follows with detailed discussions of issues associated with TSA designs and performance characteristics. To conclude the article, some recent developments in TSA arrays and their applications are highlighted.
Wavelet Transforms
Authors: Deans Stanley R. , Heine John J. , Gangadharan Deepak , Qian Wei , Kallergi Maria , Clarke Laurence P.
Published: November 2024

Functions that oscillate over time are often called waves. If the function is such that it oscillates only in a localized region and goes to zero outside the region it may be called a wavelet. Thus we say wavelets are localized waves.

The fundamental role of the wavelet transform is to facilitate the analysis of signals or images according to scale. Wavelets are functions with some special mathematical properties that serve as a tool for efficiently dividing data into a sequence of frequency components without losing all information about position.
High‐Temperature Superconductors
Authors: Mansour Raafat R.
Published: November 2024

This article provides an overview of the microwave applications of high‐temperature superconductor (HTS) technology. The main characteristics of HTS materials are outlined, highlighting the differences between superconductors and normal conductors. The article also presents the most recent progress in the development of HTS filters, multiplexers, cryogenic receivers, delay lines, and antennas. A brief summary of cryocooler technology and cryopackaging requirements is presented. The benefits of using HTS technology in wireless and satellite systems are also discussed. Newcomers to the field are encouraged to continue reading about the subject to understand more about the potential challenges and limitations of this revolutionary technology.
Superconducting Filters and Passive Components
Authors: O’Callaghan Juan M. , Collado Carlos , Talisa Salvador H. , Mateu Jordi
Published: November 2024

This article gives an overview of the applications of high‐temperature superconductors for passive microwave devices, with an emphasis on planar filters. It includes a description of the basic characteristics of these superconducting materials and relates these characteristics to device performance. In the case of filters, the low loss of superconducting films allows the development of small, planar filters with superior performance. One important application of these filters is preselector filters for receiver front‐ends, because they combine high‐frequency selectivity with low insertion loss and low noise figure because of the low temperatures of operation.

The article also gives a short overview of applications of high‐temperature superconducting materials in planar delay lines, cryocoolers, and cryogenic packaging.
Frequency Synthesizers
Authors: Goldberg Bar-Giora
Published: November 2024

Traditionally, frequency synthesis (FS) generated a single tone with variable frequency or amplitude. There are new applications, especially for testing and simulation, that require multitone generation and even arbitrary wave generation, which relate to digital frequency synthesis. Since the late 1970s, FS has evolved from mainly analog to a mix of analog, radiofrequency (RF), digital, and digital signal processing (DSP) technologies.
Dielectric Permittivity and Loss
Authors: Das-Gupta D. K.
Published: November 2024

The present article briefly reviews the electrostatic concepts that lead to time‐ and frequency‐dependent dielectric phenomena together with the models of dielectric relaxation behavior in various materials. It also includes some explanations for the dielectric aging of insulating materials under high fields in humid environments.
Multiresolution Techniques
Authors: Chen Yinchao , Cao Qunsheng , Mittra Raj
Published: November 2024

We begin by reviewing the foundation of the MRTD scheme—the multiresolution analysis (MRA ), and then exploring the properties of the scaling functions and wavelets. Also, we demonstrate the applications of the MRTD technique by analyzing a transverse electromagnetic (TEM ) wave propagation in a dielectric layered stratified space and an integrated microwave circuit, which can be extended to solve electromagnetic engineering problems of a general nature.
Klystron
Authors: Tallerico Paul J.
Published: November 2024

The klystron is a vacuum electron device for transforming DC energy into RF energy, and it may be either an oscillator or an amplifier. In the past, small reflex klystron oscillators were used as local oscillators in microwave receivers, but these oscillators are not used in modern equipment. Therefore the amplifier klystron is emphasized in this article.
Microwave Resonance Plasma Source
Authors: Taube Alexander L. , Demyashev Gregory M.
Published: November 2024

This article summarizes important aspects of a microwave resonance plasma source (MRPS ) based on the resonance phenomenon and running at atmospheric pressure. The novel MRPS using the high‐efficiency tunable cylindrical resonant cavity of TM013mode and operating at 2.45 GHz, was designed and manufactured. The MRPS was successfully approved with different carrier gases (N2, Ar, He) and precursor (gases, liquids, and powders) for creation of thermal plasma torch.

Some examples of technological applications are highlighted. The feasibility of using the MRPS for nitriding/oxinitriding of Ti, 304 and 316 stainless steel, and 5140 steel by pure N2and with air (the mixture of N278 vol% +O221 vol%) was confirmed. For the purpose of plasma chemistry applications, two gaseous systems were chosen. The first one is CO2–H2O–N2, which imitates exhaust/flue gases. The second one is CO2–N2, which is of interest for deposition of superhard nanocrystalline carbon nitride (C3N4), the hardness of which is comparable to that of diamond. The MRPS commercially applicable in industry is practical for plasma chemistry, materials processing, coating deposition, surface treatment, and other applications.
Tunnel Devices
Authors: Sargent Edward H. , Xu J. M.
Published: November 2024

Tunnel devices take advantage of the wave‐like properties of charge carriers in implementing a desired function. The term tunneling refers to the movement of matter from one side of an energetic barrier to the other even though it does not possess sufficient energy to overcome the potential barrier according to the laws of classical mechanics. Instead, the quantum‐mechanical wave function of the particle penetrates inside the barrier and extends into the medium on the far side. Tunnel devices typically possess nonlinear, nonmonotonic current‐voltage characteristics and are characterized by very rapid fundamental propagation times. They find application in such diverse areas as microwave oscillators; multiple‐level logic, switches, memory elements; and lasers.
Electromagnetic Subsurface Remote Sensing
Authors: Chen S. Y. , Chew W. C.
Published: November 2024

Subsurface electromagnetic (EM) methods are applied to obtain underground information that is not available from surface observations. Subsurface EM methods include a variety of techniques depending on the application, surveying method, system, and interpretation procedure, and thus a “best” method simply does not exist. One of the most challenging parts of subsurface EM methods is interpretation of the data. Data interpretation is also a critical factor in evaluating the effectiveness of the system. In the following sections, we will use several typical applications to outline the basic principles of subsurface EM methods. Physical insight is emphasized rather than rigorous mathematical analysis.
Antenna Reverberation Chamber
Authors: Kouveliotis N.K. , Trakadas P.T. , Heretakis I.I. , Capsalis C.N.
Published: November 2024

The use of the reverberation chamber for performing electromagnetic compatibility (EMC) tests and antenna measurements is examined in this article. This kind of chamber exhibits a significant number of advantages compared to the other commonly used test sites. Its low cost, compact, and easily built structure simultaneously appears to host a very “convenient” electromagnetic environment inside the enclosure, with regard to the requirements that are posted by the standard that is followed during the EMC or any other type of test such as antenna measurements. More specifically, antenna radiation efficiency measurements prove to be satisfactorily performed through the use of a reverberating enclosure, as well as other antenna parameters (e.g., input impedance) tests. The basic characteristics of such a structure are presented with regard to the recently introduced IEC 61000‐4‐21 specification and studies available in the literature. The field uniformity requirements are being extensively described, as well as ways of improving the achieved uniformity. The field inside a reverberating enclosure is statistically characterized with the use of the models proposed in the literature, which are experimentally verified. The use of the reverberation chamber at relatively low frequencies is presented, together with its ability to store large amounts of energy. Finally, the different ways of operating a reverberation chamber are described with regard to which of its features is (are) needed for each instance. The whole presentation marks out the usefulness of the reverberation chamber for performing electromagnetic compatibility tests as well as antenna measurements.
Ferrite Phase Shifters
Authors: Hord William E.
Published: November 2024

Phase shifters are used extensively in the microwave and millimeter‐wave region primarily as array elements in phased‐array antennas.

The article describes the evolution of ferrite phase shifters that have made the transition from the research laboratory to the production floor. Wherever possible, the author has identified the systems that use a specific type device.
Microstrip Circuits
Authors: Edwards Terry C.
Published: November 2024

The general geometry of microstrip materials and techniques for its manufacture are discussed in the article, where the basic advantages are also described in comparison with other types of MIC and MMIC transmission lines.