bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating X-Ray Sources during the Epoch of Reionization with the 21 cm Signal
Authors: Ma Qing-Bo , Ciardi Benedetta , Eide Marius B. , Busch Philipp , Mao Yi , Zhi Qi-Jun
Published: May 2021

Heating of neutral gas by energetic sources is crucial for the prediction of the 21 cm signal during the epoch of reionization. To investigate differences induced on the statistics of the 21 cm signal by various source types, we use five radiative transfer simulations that have the same stellar UV emission model and varying combinations of more energetic sources, such as X-ray binaries (XRBs), accreting nuclear black holes (BHs), and hot interstellar medium emission (ISM). We find that the efficient heating from the ISM increases the average global 21 cm signal while reducing its fluctuations and thus power spectrum. A clear impact is also observed in the bispectrum in terms of scale and timing of the transition between a positive and a negative value. The impact of XRBs is similar to that of the ISM, although it is delayed in time and reduced in intensity because of the less efficient heating. Due to the paucity of nuclear BHs, the behavior of the 21 cm statistics in their presence is very similar to that of a case when only stars are considered, with the exception of the latest stages of reionization, when the effect of BHs is clearly visible. We find that differences between the source scenarios investigated here are larger than the instrumental noise of SKA1-low at z ≳ 7–8, suggesting that in the future it might be possible to constrain the spectral energy distribution of the sources contributing to the reionization process.
Evidence for a Cosmic-Ray Gradient in the IM Lup Protoplanetary Disk
Authors: Seifert Richard A. , Cleeves L. Ilsedore , Adams Fred C. , Li Zhi-Yun
Published: May 2021

Protoplanetary disk evolution is strongly impacted by ionization from the central star and local environment, which collectively have been shown to drive chemical complexity and are expected to impact the transport of disk material. Nonetheless, ionization remains a poorly constrained input to many detailed modeling efforts. We use new and archival ALMA observations of N2H+ 3–2 and H13CO+ 3–2 to derive the first observationally motivated ionization model for the IM Lup protoplanetary disk. Incorporating ionization from multiple internal and external sources, we model N2H+ and H13CO+ abundances under varying ionization environments and compare these directly to the imaged ALMA observations by performing non-LTE radiative transfer, visibility sampling, and imaging. We find that the observations are best reproduced using a radially increasing cosmic-ray (CR) gradient, with low CR ionization in the inner disk, high CR ionization in the outer disk, and a transition at ∼80–100 au. This location is approximately coincident with the edge of spiral structure identified in millimeter emission. We also find that IM Lup shows evidence for enhanced UV-driven formation of HCO+, which we attribute to the disk’s high flaring angle. In summary, IM Lup represents the first protoplanetary disk with observational evidence for a CR gradient, which may have important implications for IM Lup’s ongoing evolution, especially given the disk’s young age and large size.
FRBs Lensed by Point Masses I. Lens Mass Estimation for Doubly Imaged FRBs
Authors: Chen Xuechun , Shu Yiping , Zheng Wenwen , Li Guoliang
Published: May 2021

Fast radio bursts (FRBs) are bright radio transient events with durations on the order of milliseconds. The majority of FRB sources discovered so far have a single peak, with the exception of a few showing multiple-peaked profiles, the origin of which is unknown. In this work, we show that the strong lensing effect of a point mass or a point mass + external shear on a single-peak FRB can produce double peaks (i.e., lensed images). In particular, the leading peak will always be more magnified and hence brighter than the trailing peak for a point-mass lens model, while the point-mass + external shear lens model can produce a less magnified leading peak. We find that, for a point-mass lens model, the combination of lens mass M and redshift z

l
in the form of M(1 + z

l
) can be directly computed from two observables—the delayed time Δt and the flux ratio of the leading peak to the trailing peak R. For a point-mass + external shear lens model, upper and lower limits in M(1 + z

l
) can also be obtained from Δt and R for a given external shear strength. In particular, tighter lens mass constraints can be achieved when the observed R is larger. Lastly, we show the process of constraining lens mass using the observed values of Δt and R of two double-peaked FRB sources, i.e., FRB 121002 and FRB 130729, as references, although the double-peaked profiles are not necessarily caused by strong lensing.
First-principles Prediction of X-Ray Polarization from Magnetic Reconnection in High-frequency BL Lacertae Objects
Authors: Zhang Haocheng , Li Xiaocan , Giannios Dimitrios , Guo Fan
Published: May 2021

Relativistic magnetic reconnection is a potential particle acceleration mechanism for high-frequency BL Lac objects (HBLs). The Imaging X-ray Polarimetry Explorer (IXPE) scheduled to launch in 2021 has the capability to probe the evolution of magnetic field in HBLs, examining the magnetic reconnection scenario for the HBL flares. In this paper, we make the first attempt to self-consistently predict HBL X-ray polarization signatures arising from relativistic magnetic reconnection via combined particle-in-cell and polarized radiation transfer simulations. We find that although the intrinsic optical and X-ray polarization degrees are similar on average, the X-ray polarization is much more variable in both the polarization degree and angle (PD and PA). Given the sensitivity of the IXPE, it may obtain one to a few polarization data points for one flaring event of nearby bright HBLs Mrk 421 and 501. However, it may not fully resolve the highly variable X-ray polarization. Due to temporal depolarization, where the integration of photons with variable polarization states over a finite period of time can lower the detected PD, the measured X-ray PD can be considerably lower than the optical counterpart or even undetectable. The lower X-ray PD than the optical thus can be a characteristic signature of relativistic magnetic reconnection. For very bright flares where the X-ray polarization is well resolved, relativistic magnetic reconnection predicts smooth X-ray PA swings, which originate from large plasmoid mergers in the reconnection region.
The Old Moving Groups in the Field of Taurus
Authors: Liu Jiaming , Fang Min , Tian Hao , Liu Chao , Yang Chengqun , Xue XiangXiang
Published: May 2021

In this work, we present a systematic search for stellar groups in the Taurus field by applying the DBSCAN algorithm to the data from Gaia DR2. We find 22 groups, consisting of 8 young groups (Groups 1–8) at ages of 2–4 Myr and distances of ∼130–170 pc, and 14 old groups (Groups 9–22) at ages of 8–49 Myr and distances of ∼110–210 pc. We characterize the disk properties of group members and find 19 new disk-bearing stars, 8 of which are in the young groups with 11 others belonging to the comparatively old groups at the ages of 8–11 Myr. We characterize the accretion properties of the group members with Hα emission lines in their Large Sky Area Multi-Object Fibre Spectroscopic Telescope spectra, and discover one source in Group 10 at an age of 10 Myr which still shows accretion activity. We investigate the kinematic relations among the old groups, find that Group 9 is kinematically related to the known Taurus members, and exclude any kinematic relations between Groups 10–22 and the known Taurus members.
Radial Velocities in the Fields of RR Lyr Variables NO Cas, NR Lyr, and V1176 Sgr
Authors: Barnes Thomas G. , Jeffery Elizabeth , Skillen Ian , Montemayor Thomas J.
Published: May 2021

We report 14 radial velocities for three field stars located near the RR Lyrae variables NO Cas, NR Lyr, and V1176 Sgr. We identified the three field stars using Gaia Early Data Release 3. Two of these stars confirm the Gaia radial velocities. The third has no previously published radial velocity.
Phylogenetic placement of the enigmatic longhorned beetle Vesperoctenus flohri Bates (Vesperidae) and a first description of its female internal structures
Authors: Haddad Stephanie , Gutiérrez Nayeli , Noguera Felipe A. , Shin Seunggwan , Svacha Petr , McKenna Duane D.
Published: May 2021

Taxonomic placement of the enigmatic monotypic Mexican longhorned beetle genusVesperoctenusBates is examined through inclusion in and reanalysis of the dataset of Haddad et al. (2018,Systematic Entomology43: 68–89). We describe and discuss the phylogenetic significance of the internal structures of a recently collectedV. flohrifemale from the Sierra de la Laguna mountain range in Mexico, the same specimen from which phylogenomic data was generated. Our phylogenomic analyses (469 genes) recoveredVesperoctenuswith maximal statistical support within the cerambyciform family Vesperidae, sister toVesperusDejean (Vesperinae).Vesperus+Vesperoctenuswere recovered sister to Philinae, and collectively form a clade sister to Anoplodermatinae. Thus, we placeV. flohriwithin Vesperidae: Vesperinae: Vesperoctenini based on analyses of large-scale phylogenomic data. Finally, we propose that the conservation status ofV. flohrimerits assessment.
Three new species of the primitively segmented spider genus Songthela (Araneae, Mesothelae) from Guizhou Province, China
Authors: Chen Zhaoyang , Li Dengqing , Li Daiqin , Xu Xin
Published: May 2021

We diagnose and describe three new species of the primitively segmented spider genus Songthela from Guizhou Province, China, based on morphological characters and molecular data: S. liuisp. nov. (♂♀), S. tianzhusp. nov. (♂♀), and S. yupingsp. nov. (♂♀). We provide the genetic distances within and among the three new species based on the DNA barcode gene, cytochrome c oxidase subunit I (COI) to support our descriptions. We also provide the COI GenBank accession codes for the three new species for future identification.
Pologne : Kaczyński tient bon
Authors: Potel Jean-Yves
Published: May 2021

La politique menée en Pologne par Jaroslaw Kaczynski fait face à un mécontentement croissant de la part de la population, comme en témoignent les manifestations, qui ont suivi l’interdiction de l’IVG dans le pays. Toutefois, le pouvoir tient bon, et l’opposition n’est pas en mesure de proposer une alternative convaincante.
Les impasses de la loi sur l’aide au développement
Authors: Giovalucchi François , Vircoulon Thierry
Published: May 2021

La loi de programmation relative au développement solidaire et à la lutte contre les inégalités mondiales masque les ambigüités de la position française sur le sujet, qui se résume à une série de bonnes intentions sans remédier aux problèmes identifiés de longue date dans les politiques de développement, comme le manque d’efficacité, l’asymétrie des relations ou la lourdeur des procédures.
L’idée libérale en question
Authors: Bujon Anne-Lorraine
Published: May 2021

Alors que le libéralisme est une force structurante de notre modernité, l’hostilité contemporaine à l’idée libérale repose sur des contresens qu’il convient de corriger. Le libéralisme est en effet une tradition plurielle, capable de se renouveler et de se combiner avec d’autres courants de pensée politique. Timothy Garton Ash le définit comme « une quête interminable pour déterminer le meilleur moyen de bien vivre ensemble dans les conditions de la liberté » . N’est-il pas temps de le rénover, pour ainsi mieux le défendre ?
L’avenir du libéralisme
Authors: Ash Timothy Garton , Chalier Jonathan
Published: May 2021

Confrontés aux tendances à l’autoritarisme, les libéraux doivent élaborer un nouveau projet politique qui conserve l’attachement à la liberté, mais qui défende aussi l’égalité et la solidarité, ainsi que l’identité et la communauté.
Des enseignants qui res(is)tent : dynamiques identitaires et investissement du champ de l’enseignement professionnel au Québec
Authors: Grossmann Sophie
Published: May 2021

Le phénomène d’abandon de la profession enseignante interroge chercheurs et décideurs nord-américains régulièrement depuis plusieurs décennies. En écho à la déscolarisation qui affecte le métier d’élève, la question du décrochage des enseignants au cours des premières années de leur carrière mobilise par ailleurs les acteurs universitaires et scolaires chargés de la formation et de l’accompagnement des enseignants dans leur intégration professionnelle. Outre les problématiques globales qui affectent l’entrée dans la profession enseignante au Québec (complexité et charge de travail, précarité, etc.), des facteurs spécifiques à la formation professionnelle au secondaire complexifient le processus de transition professionnelle dans ce secteur d’enseignement (notamment la rapidité avec laquelle s’effectue le passage du métier à l’enseignement et la rupture que constituerait le saut d’un champ professionnel à un autre). Partant d’une inversion de la perspective sur le décrochage, la présentation s’attardera à des enseignants qui, échappant aux déterminismes, persévèrent en formation professionnelle au-delà des cinq ans fatidiques. Comment apprécier la transition qu’ont opérée ces enseignants entre un avant dans leur métier et un après dans l’enseignement ? Partant d’entrevues approfondies recueillies auprès d’une vingtaine d’enseignants de la formation professionnelle au secondaire, l’analyse porte sur les processus de transition professionnelle au regard des itinéraires des enseignants dans leur(s) métier(s) et en enseignement.
Développement professionnel et paliers de professionnalité : le cas de la formation des professeurs stagiaires en Education Physique et Sportive
Authors: Ouitre Florian
Published: May 2021

Le présent article souhaite rendre compte des résultats d’un travail de recherche visant à mesurer et à comprendre les effets d’un projet de formation sur le développement des compétences professionnelles d’enseignants stagiaires en formation professionnelle (Professeurs de Lycée et de Collège en deuxième année d’I.U.F.M. dans la discipline Education Physique et Sportive). Ce projet de formation s’appuie sur une conception du fonctionnement du système didactique qui est envisagée de façon problématique. Il s’en dégage trois grandes classes de problèmes professionnels que les stagiaires, au cours de leur formation, vont avoir à identifier, à reconstruire pour progressivement envisager des pistes de solutions pour mieux prendre en charge ces problèmes. Ce travail s’inscrit dans une optique de compréhension des pratiques professionnelles des stagiaires observés. Les données de cette étude s’appuient sur des comptes-rendus de visites réalisées au cours de l’année de formation et sur les éléments de préparation fournis à ces occasions. Elles reposent aussi sur des entretiens menés à l’issue de la formation et visant à recueillir le point de vue des acteurs. Au-delà des formes que peuvent prendre ces pratiques (variété des activités enseignées et des contextes d’enseignement), nous nous sommes attachés à en dégager les logiques. Celles que nous avons mises à jour présentent au cours de l’année de formation une certaine permanence d’un stagiaire à l’autre. Cette permanence se concrétise à travers la structure des pratiques observées. Elle se traduit aussi du point de vue de leur occurrence d’apparition dans l’année de formation. Ces logiques s’apparentent à de véritables modes de fonctionnement auxquels nous attribuons le statut de paliers de professionnalité. Quatre paliers de professionnalité correspondant à quatre modalités de gestion du système didactique ont pu êtres inférés. Nous les présentons ici et dégageons quelques pistes pour élargir la portée du concept de palier de professionnalité.
Peut-on modéliser les activités physiques en éducation physique et sportive en termes de problématisation ? L’exemple de la course de haies
Authors: Bas Alain Le
Published: May 2021

Dans cet article, nous questionnerons les résultats d’une recherche antérieure en didactique de la course de haies (INRP, 1995)2 en mobilisant la théorie de la problématisation et essaierons de tester les hypothèses théoriques que constituent les cinq caractéristiques de la problématisation telles que les définit Michel Fabre : - un processus multidimensionnel, impliquant position, construction et résolution de problèmes, - une recherche de l’inconnu à partir du connu, - une dialectique de faits, d’idées, d’expériences et de théories, - une pensée contrôlée par des normes (intellectuelles, techniques, programmatiques), - une schématisation fonctionnelle du réel qui renonce à tout embrasser et à reproduire la réalité. Nous considérerons que le processus multidimensionnel représente la caractéristique de l’activité de problématisation dans la mesure où il en précise les différentes opérations, que « les normes prédéfinies » apparaissent comme des contraintes balisant le champ de la problématisation et que les autres items de la proposition originelle sont les conditions de la fonctionnalité du processus. L’adaptabilité des comportements moteurs s’exprime dans la capacité à identifier, à caractériser, à résoudre un problème, à stabiliser des réponses adaptées, à reconnaître un problème pour lequel on a une solution. Nous essaierons de voir comment en éducation physique, et précisément en course de haies, la prise en compte de la problématisation permet de repenser l’apprentissage et de l’opérationnaliser.
Situations et savoirs dans la pratique de classe
Authors: Rey Bernard
Published: May 2021

Une idée très répandue dans le monde éducatif affirme que c’est en s’affrontant à des situations que les élèves apprennent. Le présent texte tente de saisir quelles caractéristiques il faut attribuer à la notion de situation pour donner cohérence à cette idée. Comment concevoir les situations pour que du rapport des élèves à elles, des savoirs puissent émerger ? Il analyse les difficultés ainsi rencontrées et fait apparaître la nature des relations entre les notions de situation, de compétence et de savoir. Il débouche sur l’importante distinction qu’il convient d’établir entre contexte et situation.
Du concept de situation dans les didactiques de l’histoire, de la géographie et de l’éducation à la citoyenneté
Authors: Audigier François
Published: May 2021

Après avoir connu une fortune certaine dans son association avec le terme de problème, le concept de situation se voit à nouveau remis au premier rang des préoccupations didactiques avec l’arrivée des curriculums par compétences. Ces dernières appellent nécessairement une réflexion renouvelée sur les situations. En effet, les compétences sont construites et mises en œuvre en situation. Elles portent aussi sur des objets spécifiques. Ainsi, l’histoire, la géographie et l’éducation à la citoyenneté, principales disciplines de sciences sociales présentes à l’école obligatoire, étudient les actions humaines dans les sociétés présentes et passées. Le terme de situation renvoie donc à deux réalités différentes : la situation d’enseignement telle qu’elle est organisée et mise en œuvre par l’enseignant et la réalité sociale présente ou passée qui est étudiée. Dans ce texte, l’auteur dessine un parcours qui, depuis l’examen de quelques aspects des relations entre compétences et situations, le conduit à proposer deux fois deux distinctions pour décrire, comprendre et analyser les situations d’enseignement-apprentissage. Pour ce dernier moment, il s’appuie sur une recherche menée par une équipe de Suisse romande sur l’Education en vue du développement durable.
Manhunt : Unabomber : conversation avec une cabane, une boîte aux lettres et un feu tricolore
Authors: Espinosa Laurence
Published: May 2021

Les séries TV peuvent devenir des « terrains » au sens anthropologique, dans un dialogue avec la philosophie de Stanley Cavell. Et ces terrains engagent la subjectivité du chercheur comme les autres terrains anthropologiques. Ainsi la série Manhunt : Unabomber dit Cavell dans ses mots, ses images et ses sons. La cabane, la boite aux lettres et le feu tricolore, personnages – objets, disent Henry David Thoreau, le scepticisme, le langage ordinaire, la voix ou le perfectionnisme moral. L’écran nous rapproche et nous perd au rythme de la conversation qui affleure.
Le quotidien des Girls et la morale de l’ordinaire
Authors: Valkauskas Elodie , Leveratto Jean-Marc
Published: May 2021

La série télévisée américaine Girls (HBO, 2012-17), produite par Judd Apatow, écrite par Lena Dunham (qui en est également l’actrice principale, la réalisatrice et la co-productrice) met en scène « l’entrée dans la vie » de quatre jeunes femmes installées à New York et leur recherche, tout à la fois, d’un emploi et de leur identité sexuelle. La valorisation de l’expérience féminine, comprise en tant que vécu et en tant qu’agency, particularise la série. Elle se prête particulièrement bien à une étude, dans l’esprit de Stanley Cavell, de ce que nous pouvons apprendre de l’expérience que nous faisons d’un film.Les échanges écrits et oraux organisés dans le cadre d’un cours universitaire servent de dispositif d’observation de l’appropriation, par des étudiants français (21-26 ans), des situations mises en scène dans la première saison de la série.
Using Action Research to Promote Meaningful E-Service-Learning Experience for Preservice Teachers
Authors: Chesser Svetlana , Durham Kate , Aydarova Elena
Published: May 2021

Research on service-learning has documented the importance of relationships and meaningful community connections for preservice teachers' development. What remains less explored is the opportunities and challenges provided by e-service learning integrated into teacher preparation coursework. In this study, the authors utilize action research methodology to explore how preservice teachers engaged in e-service learning during the move towards remote instruction in the summer of 2020. Drawing on the analysis of students' weekly journals, final reflections, and the survey of stakeholders, they examine how e-service-learning created opportunities for students to feel connected to the community during the time of social isolation and be motivated by their ability to make an impact on children's interest in learning STEM content. The challenges emerged out of a disconnect between course content and some of the e-service learning assignments. This study's implications include better integration of e-service learning into teacher education courses.
The Challenges and Benefits of Online Instruction
Authors: Tanase Madalina F. , Hammack Shae
Published: May 2021

Because of the COVID-19 pandemic, educators everywhere transitioned to an online environment. This abrupt transition brought about some challenges: educators shifted their content and activities online, while their students attended classes and completed assignments online. This action research study analyzed the challenges experienced by an educator and her students during the summer and Fall 2020 semesters at a mid-size university. The researchers collected student surveys about their experiences with online learning. Results highlight the educator's struggle to make learning more interactive, as well as students' challenges with navigating the online platform and maintaining focus in class. Conversely, the online experience provided the following benefits: flexibility (logging in from different locations), comfort (joining class from home), and convenience (recorded class sessions). In alignment with the action research, the educator will continue to reflect on her practice in an attempt to make changes to the instruction and content of her classes.
Reflecting on Self-Reflection
Authors: Bell Andreea Roxana , Banu Diana Elena , Bordea Constanța , Bularca Elena Corina , Lazăr Elena Diana , Spuderca Lorena Mirela
Published: May 2021

This chapter discusses the challenges of online teaching faced by six English teachers in a state school in Romania in the context of the COVID-19 pandemic. As first-time action researchers, these teachers self-reflected on their challenges to make sense of their experiences as they transitioned from face-to-face to online teaching in a collaborative research self-study. Reflective practice is the conceptual framework within which the complexities and tensions of online teaching will be explored, as well as the process by which the authors have responded to the social and technological changes caused by the pandemic. Excerpts from the authors' voices highlight their personal views and experiences as online teachers. It is hoped that not only will this self-study reflection-in-action research provide some useful lessons regarding online teaching, but it will also showcase the benefits of collaboration and reflective practice and the action it led to.
Exploring the Nature of Business Strategy Change for Mental Health Practices in the Age of COVID-19
Authors: Judge De Andra , Burrell Darrell Norman
Published: May 2021

The Convergence Lab (TCL), a mental health medical group practice that provides group and individual therapy for its adult clients. TCL is a 5-year old organization with five (5) clinicians inclusive of and one (1) full-time office manager and 5 clinicians are full time staff. As a result of COVID-19, TCL has experienced an 75% decrease in revenue since patients are unable to complete their appointments in person. The paper examines how one mental health medical group practice used a management consultant to help the practice change its business strategy to respond to COVID-induced business challenges using automation and technology driven strategic approaches. This inquiry uses organizational development action research intervention and a content analysis of the literature to create real-world solutions that will have value to scholar practitioners that are doing applied research to help similar organizations that are challenged to respond to the global pandemic.
Smartphone-Based Virtual Reality as an Immersive Tool for Teaching Marketing Concepts
Authors: Zourrig Haithem
Published: May 2021

With the advent of Virtual Reality (VR) technology and the ubiquity of mobile devices, smartphone-based VR has become more affordable and accessible to business educators and millennial students. While millennials expect learning to be fun and prefer working with current technology, educators are constantly challenged to integrate new technology into the curriculum and evaluate the learning outcomes. This study examines the gain in learning effectiveness and students' intrinsic motivations that would result from the use of VR as compared to the use of traditional learning activity, namely think-pair and share. The results show that students who took part in the VR simulation demonstrated a better understanding of concepts and reported a better learning experience as compared to those who participated in the think-pair-share activity. In particular, the findings show evidence of higher intrinsic motivation and better learning outcomes.
Influence of Vertical Diffusion Cell Set-Up on In Vitro Silver Sulfadiazine Drug Release from Thermo-Responsive Cellulose Hydrogel
Authors: Al-Rajabi Maha Mohammad , Haan Teow Yeit
Published: May 2021

In-vitro drug release is used to measure the release of the silver sulfadiazine (SSD) from thermo-responsive cellulose hydrogel using a vertical diffusion cell (VDC). However, selected VDC set-up used by researchers are random, and the studies are lacking in information on the challenging sink conditions during in-vitro drug release study. The objective of this study is to examine the influence of VDC set-up on the in-vitro SSD drug release from thermo-responsive cellulose hydrogel. VDC set-up including receptor medium composition, membrane type, and stirring speed were studied. The results depicted that SSD release rate increased with increasing ammonia percentage in phosphate buffer solution. On the other hand, membrane type do not influence SSD release rate. While, increasing stirring speed results in forming vortex or air bubble entrapment underneath the membrane. 0.25 v/v% ammonia receptor medium, cellulose membrane or polysulfone membrane, and 600 rpm stirring speed are the optimum VDC set-up, confirming sink condition and discriminating ability of this optimum VDC set-up. This work has successfully studied the influence of VDC set-up on in-vitro SSD drug release from thermo-responsive cellulose hydrogel, and the optimum VDC set-up was selected.
Weibull Strength Analysis of Pineapple Leaf Fiber
Authors: Sia C.V. , Wong J.S.Y. , Thangavelu S.K. , Chong K.H. , Joseph A.
Published: May 2021

Pineapple leave fiber (PALF) can be considered as one of the green materials to the industries, which is the potential to replace the non-renewable synthetic fiber. However, the high disparity in the mechanical properties of PALF becomes an issue in structural composite design. Hence, improved Weibull distribution is utilised to quantify the tensile strength variation of PALF in various gauge lengths. The single fiber tensile test was performed after the fiber surface treatment and fiber diameter scanning. The predicted PALF strength by applying the improved Weibull distribution incorporating with conical frustum model is well compromised with experimental data compared to the traditional Weibull model.
Strength of Concrete with Recycled Manganese Slag
Authors: Ng Adeline Ling Ying , Liew Hock Rui , Wong Yew Ching
Published: May 2021

This paper studies the effect of replacing coarse aggregates with manganese slag on the mechanical properties of concrete. Air-cooled granulated manganese slag was used. The control sample was designed to achieve concrete strength of 30 MPa at 28 days. Tests were conducted on five different compositions of concrete having manganese slag to coarse aggregates ratios of 0, 0.2, 0.3, 0.4, and 1. The specimens were tested at 7, 14, and 28 days for their compressive and flexural strength. Test results revealed that all manganese slag concrete specimens had improved compressive and flexural strength. The maximum compressive strength achieved was 43.54 MPa, increased by 16% of the control specimen and the maximum flexural strength achieved was 4.50 MPa, increased by 22% of the control specimen. Both results were obtained in concrete with 0.4 manganese slag to coarse aggregate ratio. Besides, the study also showed that it might be possible to substitute all coarse aggregates in concrete with manganese slag without any loss in strength. However, it was observed that the concrete workability decreased when manganese slag was added. Nonetheless, this could be corrected using superplasticizer.
Acral pityriasis rosea: A rare variant of pityriasis rosea
Authors: Tantanasrigul Pimpa , Wichaidit Mingkwan , Kullavanijaya Preya
Published: May 2021

Pityriasis rosea (PR) is a common, selflimited inflammatory skin condition, usually affects the trunk and proximal extremities. A variety of atypical manifestations of PR have been recognized ranging from the difference in the morphology, distribution, and course. Herein, the rare form of acral PR in an adult has been illustrated as the 29- year-old Thai female who presented with generalized erythematous papules and plaques with peripheral collarette scales on the trunk and extremities, prominently on the hands and feet.[...]
Telemedicine platform COVIDREHAB for remote rehabilitation of patients after COVID-19
Authors: Gilmutdinova Ilmira R. , Kolyshenkov Vasiliy A. , Lapickaya Kristina A. , Trepova Anastasiya S. , Vasileva Valeriia A. , Prosvirnin Andrei N. , Marchenkova Larisa A. , Terentev Kirill V. , Yakovlev Maxim Y. , Rachin Andrey P. , Fesyun Anatoliy D. , Reverchuk Igor V.
Published: May 2021

The world's practice has shown the importance of medical rehabilitation, which allows increasing the effectiveness of treatment of patients with COVID-19, and also significantly reduce the risks of developing complications after COVID-19. Moreover, timely medical rehabilitation reduces the frequency of disability retirement. We developed and investigated the effectiveness of the telemedicine platform “COVIDREHAB” in order to enhance the effectiveness of the recovery period during self-isolation, as well as to provide access to rehabilitation for patients residing in remote areas or unable to undergo in-person medical rehabilitation. This pilot open clinical study includes 178 patients (108 women and 70 men) aged 32 to 82 years [mean age 50 (33-56) years] who had a moderate disease of COVID-19. We used the specialised platform COVIDREHAB for remote monitoring of the rehabilitation efficiency of patients who suffered from COVID-19. During the study, the supervising doctor assigned the patient a set of specialised questionnaires, which were filled in online. The questionnaires distributed to the patient included questions specifically designed for the COVIDREHAB remote platform as well as the mMRC (Modified Medical Research Council) questionnaire. Patients who completed the remote rehabilitation programme were found to have positive dynamics of indicators of the respiratory system functional state, and complaints.Pulmonary rehabilitation is an important part of case management for patients with respiratory diseases and plays an active role in improving lung function and general well-being of patients. Patients who completed the comprehensive medical rehabilitation program using the information and analytical system COVIDREHAB, were found to have positive dynamics of indicators of the respiratory system functional state, and complaints. Hence, at the end of the course the shortness of breath severity decreased (from 34.8% to 12.4%, as well as the feeling of lack of oxygen from 32% to 17.4%, p <0.05). We anticipate the online approach to rehabilitation will improve the functioning of the respiratory and cardiovascular systems, restore physical function, reduce anxiety and depression, and restore quality of life. An essential benefit of this program is the prevention of secondary complications and reduction of serious adverse effects of COVID-19 treatment."
COMUNICARE LA SCIENZA MEDICA NEL SETTECENTO EUROPEO: UNO SGUARDO ALLE PROSPETTIVE DI RICERCA
Authors: Agazzi Elena , Iamartino Giovanni , Mazzarello Paolo
Published: May 2021

Non disponibile.
SEMIOTICA DEGLI AFFETTI E MANIFESTAZIONI FISICHE NEI TESTI MEDICO-FILOSOFICI DI HALLE
Authors: La Manna Federica
Published: May 2021

In the mid-eighteenth century in Halle the so-called doctors-philosophers tried to develop a scientifically-based map of emotions, which included their causes and their manifestations on the body. Thanks to their scientific rigour, to the literary quality of those studies and to the growing circulation of the journals of the time – above all Unzer’s famous Der Arzt – the subject was so popular that it became central in the debate on physiognomy and pathognomics which was so vivid in the second half of the century. These theories had a powerful import on literature, contributing to the birth of the new ‘character’ in novels as different from the traditional and stereotypical sense of the term as ‘temper’ or ‘nature’. In the field of aesthetics, the effect of these studies had important repercussions on Winckelmann’s revolutionary theories related to the representation and interpretation of emotions in art.
GIOVAN BATTISTA MORGAGNI E IL DIBATTITO FRA MEDICINA RAZIONALE E MEDICINA EMPIRICA
Authors: Zampieri Fabio
Published: May 2021

Giovanni Battista Morgagni is considered the father of pathological anatomy. His contribution can be contextualized in the extraordinary development of anatomy between the seventeenth and the eighteenth centuries, because along this period anatomy became the most important among the natural sciences. A new pathology based on anatomy was possible thanks to the mechanistic perspective which characterized this science during the seventeenth century, in particular through the work of Marcello Malpighi, whom Morgagni considered as his master. The approach of Malpighi and other ‘iatromechanists’ was widely debated: supporters of mechanisms and empiricism, as well as supporters of the Ancients, or Hippocratic-Galenic medicine, and of the Moderns, or ‘Neoteric’ medicine, were opposed and interlaced. The anatomo-clinical method of Morgagni can be fully understood only by being contextualized within this debate.
Detection of Antibodies Against Prevotella Intermedia in Patients with Chronic Periodontitis and Periodontally Healthy Individuals
Authors: Dixitraj P. T. , Nayak Aarati , Bansal Shruti , Bhat Kishore
Published: May 2021

Background:

Periodontitis, an inflammatory disease of multifactorial etiology, has bacteria playing an essential role in its pathogenesis. Prevotella intermedia plays an important role in disease initiation and progression.

Objectives:

The objective was to detect immunoglobulin G (IgG) antibodies against P. intermedia in blood of periodontally healthy individuals and patients with chronic periodontitis and compare their levels.

Materials and Methodology:

A total of 72 subjects were included, 36 subjects in the healthy group and 36 subjects in the chronic periodontitis group. Subgingival plaque sample and blood sample were obtained from each study subject. Samples were processed in the Department of Microbiology and Immunology. P. intermedia were confirmed using the culture method and serum IgG levels were assessed using ELISA (enzyme-linked immunosorbent assay) technique. Comparison between healthy and chronic periodontitis groups was done using independent t-test.

Results:

IgG levels against P. intermedia were more in the chronic periodontitis group compared to the healthy group, and the difference was statistically significant.

Interpretations and Conclusions:

Increased levels of IgG antibodies against P. intermedia are associated with periodontal disease. This elevated antibody activity might help to neutralize the effects of the bacterium. IgG antibody level against P. intermedia is a promising indicator in the serological diagnosis of periodontal disease. In chronic periodontitis, the antibody titer in the patient's serum against P. intermedia is raised and could be used as a diagnostic aid.
Short Screening for Diabetic Foot Disease in an Omani Population at Al-Dahira, Sultanate of Oman
Authors: Marshoudi Sabria AL , Ahmed Fatma , Peeran Syed Wali , AlBurji Amru , Al-Kalbani Khalid , Yousf Sabri M.
Published: May 2021

Objective:

This study aims to implement a short primary health-care screening program for diabetic foot disease (DFD) in diabetic patients and to detect the prevalence and predictors of the DFD, to determine their positive risk factors for DFD by identifying patients who have neuropathy or vascular disease, and to examine whether the predictors (neuropathy and vasculopathy) have a significant effect on DFD.

Subjects and Methods:

This study is a cross-sectional study conducted in different diabetic clinics located in health centers across Al-Dahira, Oman. A single, trained clinician from each health center was selected to complete the questionnaire. The sample was randomly selected among subjects already diagnosed as diabetic patients. The study was carried from July 2017 to September 2017. Diabetes mellitus (DM) patients (Type-1 and Type-2) can be affected by DFD. In Al-Dahira, Oman, both Type-I and Type-II DM visited the same clinics. The screening carried out consisted of sections dealing with information of the subjects including their smoking status, number of visits, and details about their diabetic status. A detailed examination of DF was carried over if present in the subjects. The areas that were screened for DF included skin assessment, structural examination of the DF, vascular assessment, neuropathy assessment, as well as DF ulcer assessment.

Results:

Out of 216 patients, the mean age was 60.56 years (standard deviation 12.74) with a range of 25 years to 97 years. Out of the total patients, there were (164 patients) 75.9% of cases are DFD. However, the prevalence of foot ulcer, gangrene, and amputations were 4.2%. Among the studied subjects, 65.9% had poor glycemic profile value. Most of the patients had a history of diabetes for more than 5 years. The results showed that the age (P = 0.038 < 0.05), physical activity (P = 0.034 < 0.05), and neuropathy (P = 0.33 < 0.05) had an association with DFD.

Conclusions:

A short primary health-care screening program for DFD in diabetic patients is considered a useful tool and a helpful method to increase the awareness of DFD at the community level. Further, it helps to evaluate the level of the patient's risk for prevention and further management.
Performance Evaluation of Ultrasonic Imaging System (Part I)
Authors: Oglat Ammar A. , Dheyab Mohammed Ali
Published: May 2021

Background:

Diagnostic ultrasound or sonography is an image which can provide valuable information for diagnosing and treating a variety of diseases and conditions. This experiment was done to check the performance and evaluate the ultrasonic imaging system. There were three tests performed in this experiment: dead zone (transducer ring-down), vertical measurement calibration, and horizontal measurement calibration.

Methods:

The evaluation was made by performed all the tests with different depth on two different multipurpose phantom model #539. The tests were also performed by two different probes which were curved and flat (linear probe). The images were taken, and the measurements were made by electronic calipers on the ultrasound machine system. Observations and evaluations were done via all images and measurements taken.

Results:

The images formed by two various probes were different. The penetration settings were different since the depths were different. The depth influenced the penetrations to the formed image. From the comparison of all results and measurements recorded were all under the accepted value of the standard that was given by the manufacture of the phantom.

Conclusion:

Therefore, it can be concluded that the measurements were all not exceeding 2% of the standard value given based on the result that we get.
Pancytopenia with hemophagocytic lymphohistiocytosis in Plasmodium falciparum
Authors: Chaudhry Shewta , Arya Aditi , Matlani Monika , Singh Vineeta , Meena Shyam Sundar
Published: May 2021

Hematological manifestations such as anemia and thrombocytopenia are known complications in malaria. Here, we report two cases presented as pancytopenia with hepatosplenomegaly and initial diagnosis kept as hematological malignancy like leukemia but later on its diagnosed as malaria-associated hemophagocytic lymphohistiocytosis which is a rare entity. The aim of this report is to draw the attention of physicians, especially in tropical countries such as India and Sub-Saharan nations to keep in mind this uncommon presentation of malaria, though the exact pathophysiological mechanism still remains obscure.
Pulmonary cryptosporidiosis in a case of adenocarcinoma of stomach
Authors: Chaudhari Kavita , Gurushankari B. , Rajkumari Nonika , Joseph Noyal Mariya , Amaranathan Anandhi , Sathasivam Sureshkumar , Barathi Deepak , Kate Vikram
Published: May 2021

Cryptosporidium species are commonly known to cause chronic intractable diarrhea in patients suffering from human immunodeficiency virus (HIV)-acquired immunodeficiency syndrome, however extra-intestinal presentations have been rarely reported. Hereby, we report a rare case of isolated pulmonary cryptosporidiosis in a 75-year-old HIV-negative patient with metastatic carcinoma of the stomach who was managed conservatively with hemostatic radiotherapy for palliative care. The patient had presented with cough with expectoration for 2 months. Sputum microscopic examination was suggestive of pulmonary cryptosporidiosis. There was no evidence of intestinal cryptosporidiosis. Therapy for pulmonary cryptosporidiosis was started with tablet nitazoxanide. The patient succumbed to the disease few days later following discharge. Although rare, patients with disseminated gastrointestinal malignancy can potentially have isolated pulmonary cryptosporidiosis.
In vitro antiplasmodial activity of Phyllanthus amarus against Plasmodium falciparum and evaluation of its acute toxicity effect in mouse model
Authors: Aliyu Karimatu , Mohammed Yusuf , Abdullahi Idris Nasir , Umar Amina Abdullahi , Bashir Fatima , Sani Mujahid Nura , Kabuga Auwal Idris , Adamu Al-Mukhtar Yahuza , Akande Azeez Oyebanji
Published: May 2021

Background:

The emergence of widespread resistance of Plasmodium species to most antimalarial drugs has led to a more vigorous and concerted research on traditional medicinal plants for the treatment of malaria.

Objective of Study:

The study was aimed to investigate the in vitro antiplasmodial activity of crude ethanolic and aqueous extracts of Phyllanthus amarus against clinical isolates of Plasmodium falciparum in Northwestern Nigeria.

Materials and Methods:

The plant was extracted using two solvents, water and ethanol, where a high yield was obtained from the aqueous extracts (11.9%) as compared to the ethanolic extract (9.64%). The extracts were evaluated in vitro at concentrations of 6.25, 12.5, 25, 50, and 100 μg/ml, and the level of potency in each case was expressed as the concentration of the extract that exhibited a 50% reduction of the parasites relative to control (100%) parasitemia. Artemether-lumefantrine was used as a positive standard in the assay.

Results:

All extracts showed a significant reduction in parasite growth relative to control (P ≤ 0.05). Ethanolic extract exhibited a higher antiplasmodial activity of 76.8%, half-maximal inhibitory concentration (IC50) of 5.80 μg/ml, and aqueous extract had an activity of 75.3%, IC50 of 7.94 μg/ml. Both extracts exhibited very active antiplasmodial activity. Oral acute toxicity test in the doses of 500, 1000, and 1500 mg/kg showed no sign of toxicity on albino mice after 48 h.

Conclusion:

Although there was an increase in appetite after 24 and 48 h, the findings from this study show that P. amarus possesses a promising antimalarial activity which can be exploited for malaria therapy and justifies the traditional use of the plant in malaria treatment.