bluuebunny/crossref_metadata_2025 huggingface dataset:
Caltech-NRAO Stripe 82 Survey (CNSS). IV. The Birth of Radio-loud Quasar 013815+00
Authors: Kunert-Bajraszewska Magdalena , Wołowska Aleksandra , Mooley Kunal , Kharb Preeti , Hallinan Gregg
Published: July 2020

It is believed that the gas accretion onto supermassive black holes is the main process of powering this quasar’s luminous emission, which occurs in optical, UV, and X-ray regimes and less frequently in radio waves. The observational fact that only a few percent of quasars are radio-loud is still an unresolved issue concerning the understanding of the active galactic nucleus (AGN) population. Here we present a detection of a rapid transition from the radio-quiet to the radio-loud mode in quasar 013815+00 (z = 0.94) which coincides with changes of its UV–optical continuum and the low ionization Mg ii broadline. We interpret this as an enhancement of accretion onto a central black hole of about 109 solar masses. As a consequence a new radio-loud AGN was born. Its spectral and morphological properties indicate that it went through the short gigahertz-peaked spectrum phase at the beginning of its activity and has now stabilized its flux density at the level of a few millijansky. The radio morphology of 013815+00 is very compact and we predict that with such short-term jet activity its development will be very slow. The observed luminosity changes of the accretion disk are shorter than the lifetime of the new radio phase in 013815+00.
Cosmology-independent Estimate of the Hubble Constant and Spatial Curvature using Time-delay Lenses and Quasars
Authors: Wei Jun-Jie , Melia Fulvio
Published: July 2020

With the distance sum rule in the Friedmann–Lemaître–Robertson–Walker metric, model-independent constraints on both the Hubble constant H
0 and spatial curvature

can be obtained using strong lensing time-delay data and Type Ia supernovae (SNe Ia) luminosity distances. This method is limited by the relatively low redshifts of SNe Ia, however. Here, we propose using quasars as distance indicators, extending the coverage to encompass the redshift range of strong lensing systems. We provide a novel and improved method of determining H
0 and

simultaneously. By applying this technique to the time-delay measurements of seven strong lensing systems and the known ultraviolet versus X-ray luminosity correlation of quasars, we constrain the possible values of both H
0 and

, and find that

km

and

. The measured

is consistent with zero spatial curvature, indicating that there is no significant deviation from a flat universe. If we use flatness as a prior, we infer that

km

, representing a precision of 2.5%. If we further combine these data with the 1048 current Pantheon SNe Ia, our model-independent constraints can be further improved to

km

and

. In every case, we find that the Hubble constant measured with this technique is strongly consistent with the value (∼74 km

) measured using the local distance ladder, as opposed to the value optimized by Planck.
Multiwavelength Observations of 2HWC J1928+177: Dark Accelerator or New TeV Gamma-Ray Binary?
Authors: Mori Kaya , An Hongjun , Feng Qi , Malone Kelly , Prado Raul R. , Schutt Theo , Dingus Brenda L. , Gotthelf E. V. , Hailey Charles J. , Hare Jeremy , Kargaltsev Oleg , Mukherjee Reshmi
Published: July 2020

2HWC J1928+177 is a Galactic TeV gamma-ray source detected by the High Altitude Water Cherenkov (HAWC) Observatory up to ∼56 TeV. The HAWC source, later confirmed by the High Energy Stereoscopic System, still remains unidentified as a dark accelerator since there is no apparent supernova remnant or pulsar wind nebula detected in the lower-energy bands. The radio pulsar PSR J1928+1746, coinciding with the HAWC source position, has no X-ray counterpart. Our SED modeling shows that inverse Compton scattering in the putative pulsar wind nebula can account for the TeV emission only if the unseen nebula is extended beyond

r
∼
4
′

. Alternatively, TeV gamma-rays may be produced by hadronic interactions between relativistic protons from an undetected supernova remnant associated with the radio pulsar and a nearby molecular cloud G52.9+0.1. NuSTAR and Chandra observations detected a variable X-ray point source within the HAWC error circle, potentially associated with a bright infrared (IR) source. The X-ray spectra can be fitted with an absorbed power-law model with N
H = (9 ± 3) × 1022 cm−2 and ΓX = 1.6 ± 0.3 and exhibit long-term X-ray flux variability over the last decade. If the X-ray source, possibly associated with the IR source (likely an O star), is the counterpart of the HAWC source, it may be a new TeV gamma-ray binary powered by collisions between the pulsar wind and stellar wind. Follow-up X-ray observations are warranted to search for diffuse X-ray emission and determine the nature of the HAWC source.
Electron Density Structure of the Local Galactic Disk
Authors: Ocker Stella Koch , Cordes James M. , Chatterjee Shami
Published: July 2020

Pulsar dispersion measures (DMs) have been used to model the electron density of the interstellar medium (ISM) in the Galactic disk as a plane-parallel medium, despite significant scatter in the DM-distance distribution and strong evidence for inhomogeneities in the ISM. We use a sample of pulsars with independent distance measurements to evaluate a model of the local ISM in the thick disk of the Galaxy that incorporates turbulent fluctuations, clumps, and voids in the electron density. The latter two components are required because about one-third of the lines of sight are discrepant from a strictly plane-parallel model. A likelihood analysis for smooth components of the model yields a scale height

kpc and a mid-plane density n
0 = 0.015 ± 0.001 cm−3. The scatter in the DM-distance distribution is dominated by clumps and voids but receives significant contributions from a broad spectrum of density fluctuations, such as a Kolmogorov spectrum. The model is used to identify lines of sight with outlier values of DM. Three of these pulsars, J1614−2230, J1623−0908, and J1643−1224, lie behind known H ii regions, and the electron density model is combined with Hα intensity data to constrain the filling factors and other substructure properties of the H ii regions (Sh 2–7 and Sh 2–27). Several pulsars also exhibit enhanced DM fluctuations that are likely caused by an intersection of their lines of sight with the superbubble GSH 238+00+09.
Checklist and distribution of Collembola from Greater Puerto Rico
Authors: Ospina-Sánchez Claudia , Soto-Adames Felipe , González Grizelle
Published: July 2020

Springtails (Arthropoda, Hexapoda, Collembola) are small arthropods commonly found in soil, litter and other habitats all around the Globe. More than 9,000 species have been described worldwide, but knowledge about their diversity and distribution remains far from complete. Reports of springtail diversity in the Antilles are uneven, some islands are relatively well known, whereas others have not been explored at all. The fauna of Puerto Rico is reasonably well known, but many recent reports are scattered in published literature and unpublished theses.

Here, we present a summary of all springtail species identified from the Bank of Puerto Rico, including unpublished records. As a result, we list 146 species including 43 unnamed, included in 65 genera and 17 families. Most species, 33, belong to Entomobryidae, but this possibly reflects the taxonomic expertise of specialists working in Puerto Rico rather than a real bias in the distribution of higher taxa in the islands. In addition to the new records, the database provides information on the world and local distribution of species listed. The dataset, presented here, is work in progress and will be updated as ongoing taxonomic inventories are completed.
Vers une allocation unique ?
Authors: Lignon Vincent
Published: July 2020

Cet article estime l’impact d’une réforme d’allocation unique familialisée visant à fusionner les aides à destination des ménages modestes sur la pauvreté et l’incitation à l’activité. Les résultats montrent qu’il est possible de simplifier ces aides sans surcoût pour les finances publiques tout en diminuant de manière significative la pauvreté et les inégalités. La décomposition de ces indicateurs montre cependant que certaines catégories fragiles de la population sont défavorisées par ce type de dispositif, notamment les familles monoparentales, les bénéficiaires de l’AAH et de l’ASPA. Par ailleurs, en termes d’incitations à l’activité, les scénarios étudiés ne permettent pas de lisser et d’homogénéiser les taux marginaux d’imposition. Classification JEL : D31, H31, I32, C63.
L’adaptation de la politique d’assurance vieillesse au vieillissement (1961-2015)
Authors: Laroque Michel
Published: July 2020

La politique d’assurance vieillesse s’est profondément adaptée au vieillissement de la population. Construite dans les années 1910, 1930 et 1945, l’assurance vieillesse a été marquée d’abord par le rapport Laroque de 1961, qui renouvelle ses principes. La prise de conscience du vieillissement, issu du baby-boom et de l’augmentation constante de l’espérance de vie qui traduit le « rajeunissement » de personnes âgées en bonne santé, n’intervient qu’à partir des années 1980. Elle génère, pour assurer la pérennité du système de retraite, qui dépend de « prélèvements sur la production de biens ou la création de service des actifs », la réforme de 1993 et les réformes successives du XXI e  siècle qui ne sont pas terminées.
Dialectique ramiste et conscience puritaine : le cas de William Ames (1576-1633)
Authors: Adrián Lara Laura
Published: July 2020

William Ames (1576-1633) a incarné une autorité fondamentale pour les puritains qui ont émigré en Nouvelle-Angleterre. Dans son œuvre, il a la singularité d’allier ses convictions religieuses à une mentalité ramiste. Ames considère la méthode de Ramus comme une manière adéquate de comprendre l’acquisition et la transmission des savoirs. Le système ramiste s’applique aussi au domaine de la théologie et à certaines questions liées au gouvernement de l’individu. Cet article vise à mettre en lumière cette combinaison entre le puritanisme et le ramisme qui caractériserait une façon bien particulière de concevoir le gouvernement de l’individu : un modèle qui renforce la volonté de l’individu et sa capacité de contrôle, en tant qu’instruments essentiels de gouvernement, et qui renferme un objectif émancipateur et égalitaire.
La réception de Petrus Ramus dans la pensée catholique
Authors: Ramis-Barceló Rafael
Published: July 2020

Un itinéraire est proposé pour comprendre la réception de Petrus Ramus dans la pensée catholique, puisqu’il s’agit d’un sujet totalement inexploré : 1) 1545-1585 (stade de compréhension et d’absorption des idées de Ramus), 2) 1585-1640 (époque du combat apologétique, confrontation et éclectisme), 3) 1640-1670 (période d’étude et de discussion détaillée des auteurs scolastiques et des rationalistes), et 4) après 1670 (époque de suspension et de dissolution progressive de l’intérêt pour les œuvres de Ramus). La réception de Ramus dans les œuvres de Lalemandet, Mersenne, Sorel, Gassendi et Caramuel est particulièrement étudiée, ainsi que l’influence de Ramus sur les jésuites. On conclut à une réception très différente. Les auteurs les plus aristotéliciens (Mas, Raynaud...) étaient absolument contre La Ramée, alors que d’autres avaient une position plus éclectique (Lalemandet, Caramuel), d’autres estimaient son travail (Mersenne, Gassendi) et certains ont formulé un jugement très élogieux (Sorel).
Optical Performance of a Trifocal IOL and a Novel Extended Depth of Focus IOL Combined With Different Corneal Profiles
Authors: Ruiz-Alcocer Javier , Lorente-Velázquez Amalia , Hernández-Verdejo José Luis , De Gracia Pablo , Madrid-Costa David
Published: July 2020

PURPOSE:

To assess the effect of prior myopic ablations on the optical performance of a trifocal diffractive intraocular lens (IOL) and a novel extended depth of focus (EDOF) diffractive design.

METHODS:

The novel XACT Mono-EDOF ME4 diffractive IOL (Santen Pharmaceutical) and the trifocal diffractive FineVision IOL (PhysIOL) were analyzed standing alone and combined with a simulated myopic corneal ablation. The optical quality of the IOLs in both situations was evaluated with the PMTF optical bench (LAMBDA-X). The through-focus modulation transfer function (MTF) curves and the MTF at three different focal points (+0.50, 0.00, and −0.50 diopters [D]) were recorded.

RESULTS:

The through-focus MTF curves showed three differentiated peaks for the trifocal IOL and two overlapped peaks for the EDOF IOL. The presence of simulated myopic corneal ablations induces a −0.50 D shift on the overall through-focus curves and softens the multifocal properties of both lenses by decreasing the variations through focus of the MTF. For the analysis of the lenses standing alone, the highest MTF values were obtained for an object vergence of 0.00 D. For a simulated myopic corneal ablation, both IOLs showed better optical quality results at −0.50 D.

CONCLUSIONS:

The trifocal IOL provides better optical quality at far and near distances when analyzed alone. The EDOF IOL optical properties are more stable when a myopic ablation is introduced. Preoperative calculations of both lenses should consider that prior myopic corneal ablations induce a −0.50 D shift on their far peak quality.

[
J Refract Surg
. 2020;36(7):435–441.]
« Alter remus aquas, alter mihi radat arenas » : composition des liens et « souci de soi » chez Montaigne
Authors: Guerrier Olivier
Published: July 2020

En s’appuyant sur un passage essentiel du chapitre « De la vanité » (III, 9) des Essais de Montaigne et sur une citation de Properce, on tentera dans cet article de reprendre à nouveaux frais la question de la gestion des liens, publics et privés, chez Montaigne, en la rapportant à l’éthique de la modération, à l’équilibre pyrrhonien, au « rolle » et à sa logique, et surtout, en dernière instance, à certains aspects de la tradition du « souci de soi » telle que Michel Foucault l’avait envisagée dans certains de ses cours du Collège de France.
Active Learning Strategies for Online College Classrooms
Authors: Kamenetskiy Marina
Published: July 2020

The term active learning is also known as “learning by doing”; it is where students are presented with a variety of learning activities that encourages thinking and reflection. Educational leaders recognize the value of promoting active learning in the educational setting and encourage their faculty to apply active learning techniques in their online classrooms to increase learner interest and motivation. This chapter identifies various active learning strategies that can be applied to any discipline in any online course, as well as presents different examples of active learning activities. Active learning strategies can include group work, simulations (role play), and games, in order to build learners' critical thinking, problem-solving, and collaboration skills.
Beyond Onboarding
Authors: Espinet Tamara , Vuong Phuong M. , Filback Robert A.
Published: July 2020

The rise of online programs has led to growing awareness that effective online teaching requires specialized instructional knowledge and skills. However, most online programs emphasize technology onboarding in lieu of ongoing professional development designed to support faculty in improving their online instruction. This chapter reinforces the need for comprehensive professional development efforts focused on improving online teaching and highlights the latest practices based on studies by the authors of leading online graduate programs. Evidence-based recommendations for providing ongoing professional development to support faculty's online teaching success are also outlined and fall into four overarching categories: (1) align organizational goals to create a culture of continuous instructional improvement, (2) model online learning principles in professional development efforts, (3) distinguish technology training from instructional development, and (4) employ multiple strategies to create ongoing, sustainable professional development efforts to support online instruction.
Flujos comerciales agroalimentarios en una región transfronteriza dominico/haitiana: Elías Piña/Departamento Central
Authors: Dilla Alfonso Haroldo , Contreras Vera Camila
Published: July 2020

Un factor clave para el estudio de las regiones transfronterizas lo constituyen las cadenas de valor que organizan los intercambios económicos. Este artículo explora este tema en una región de la frontera dominico-haitiana (Elías Piña-Departamento central) centrando su análisis en las cadenas agroalimentarias. A efectos de lo anterior, se estudiaron seis productos agrícolas que cruzan el borde en una u otra dirección, para lo cual se realizaron observaciones, recopilaciones estadísticas y entrevistas a actores clave de estos procesos. Las cadenas muestran rasgos típicos de los intercambios desiguales en las fronteras, pero también la manera como la región –y en particular sus productores– participa marginalmente en las utilidades de esta actividad económica transfronteriza.
Incertidumbre ante los nuevos escenarios migratorios. Transformaciones recientes en la migración en tránsito en Costa Rica
Authors: Chaves Groh María José
Published: July 2020

Costa Rica se ha identificado históricamente como el principal receptor de migración en la región centroamericana. Sin embargo, a partir del año 2009 se empiezan a identificar importantes transformaciones en el escenario de tránsito que desembocan en dos importantes emergencias: la primera en noviembre de 2015 con la llegada masiva de personas cubanas y la segunda en abril de 2016 con la llegada de personas originarias de diferentes países del Caribe, África y Asia. A partir del análisis de notas de prensa, de la revisión de informes de situación de instituciones vinculadas con la atención de estas emergencias y de entrevistas a actores clave, se han identificado los principales desafíos que enfrentó el Estado costarricense en la atención de estas emergencias y se analizan las transformaciones registradas en el escenario migratorio de tránsito. Como resultado de este proceso investigativo se concluye que el país debe repensar su política migratoria desde un enfoque prospectivo y versátil, trascendiendo su especialización en la inmigración y asumiendo de forma integral el papel que le corresponde en el entramado migratorio regional.
Élites tarapaqueñas y migrantes chilenos: criminalización, delitos y rebeldías en el Iquique peruano: 1870-1879
Authors: Lo Chávez Damián
Published: July 2020

Este trabajo explora una etapa temprana de la historia social de Iquique: los años previos a la Guerra del Pacífico y la última etapa de la soberanía peruana, período caracterizado por el crecimiento acelerado de la industria salitrera y del puerto de Iquique. En los años estudiados, la provincia recibió una gran cantidad de inmigrantes chilenos, principalmente peones de la zona central del país, quienes experimentaban una temprana fase de transición al trabajo asalariado. En la ciudad desplegaron múltiples formas de rebeldías contra el orden urbano de las élites tarapaqueñas. Estas últimas pretendían convertir a Iquique en una ciudad moderna, funcional a la acumulación de capital, para lo cual intentaron incrementar el control social sobre el espacio urbano y sus habitantes. Este artículo reivindica el conflicto social entre los sectores populares urbanos y las élites citadinas como un importante factor de desarrollo urbano. A través del estudio de fuentes primarias se hace una aproximación a la sociedad del período en cuestión, analizando las diversas variables que se articulan en torno al conflicto social y evaluando su impacto en la configuración de la ciudad.
¿Una peregrinación extranjera? Espacialidad y estrategias identitarias del colectivo boliviano en Argentina
Authors: Dawidiuk Carlos Luciano , Vogel Carolina
Published: July 2020

La colectividad boliviana en Argentina celebra a la Virgen de Copacabana movilizándose hacia la ciudad de Luján, el centro de peregrinación más grande del país, cada primer fin de semana del mes de agosto desde hace más de sesenta años. La circulación de múltiples símbolos de reivindicación y reafirmación identitarias de este colectivo, como así también sus músicas y danzas, que manifiestan mediante diversas prácticas corporales esta pertenencia, imprimen a esta celebración un carácter distintivo respecto a otras manifestaciones que históricamente han tenido como epicentro a esta ciudad. Pero su denominación como “peregrinación boliviana” entraña una representación identitaria y del ritual religioso que no da cuenta de la hibridez de este fenómeno, en el que tanto los símbolos, las prácticas y los participantes exceden la caracterización de esta manifestación como extranjera. Así, nos proponemos indagar y analizar las estrategias identitarias transculturales y transmediales en el escenario móvil de la peregrinación, los modos en que se articulan y despliegan esos discursos –símbolos y prácticas desterritorializados y reterritorializados en un espacio-movimiento heterotópico– que interpelan los límites entre los espacios sagrados y profanos reactualizando en el ritual aspectos de la memoria histórica que permiten resignificar los vínculos entre la identidad y el territorio.
El rol de los gobiernos locales en las investigaciones migratorias en Argentina
Authors: Nicolao Julieta
Published: July 2020

Este artículo se propone realizar una revisión bibliográfica sobre la evolución del campo de los estudios migratorios en Argentina, reconociendo la necesidad de avanzar en investigaciones sobre el papel que desempeñan los gobiernos locales en materia de formulación e implementación de políticas migratorias. Se argumenta que, si bien los municipios no siempre cuentan con los soportes normativos, las competencias suficientes o los recursos necesarios, en la práctica deben dar respuesta a distintos temas asociados a la inserción social de los migrantes y al reconocimiento efectivo de derechos. Esta situación, que los convierte en actores cada vez más importantes en la gestión migratoria contemporánea, reclama una comprensión más acabada del sector académico especializado. Además de identificar este vacío de conocimiento, el trabajo propone algunas directrices para abordar la temática en futuras publicaciones, y destaca la necesaria incorporación de disciplinas sociales como la ciencia política y otras afines al estudio del Estado y las políticas públicas, entendiendo que están llamadas a realizar importantes contribuciones en este campo de estudios.
Formación interdisciplinaria, colaboración y mirada comparada en el estudio de la convivencia y el multiculturalismo cotidiano: una entrevista a Amanda Wise y Selvaraj Velayutham
Authors: Chan Carol , Ramírez Carolina
Published: July 2020

En la última década los estudios acerca de la convivencia y la multiculturalidad cotidiana han cobrado renovada importancia en los estudios étnicos, migratorios y urbanos. Esta entrevista recoge las voces de la investigadora australiana Amanda Wise, y su par singapurense Selvaraj Velayutham, quienes en solitario y en colaboración han generado notables aportes para el estudio de la experiencia de vivir juntos a través de la diferencia cultural en contextos urbanos diversos. En esta conversación, junto con discutir su marco conceptual, se recogen aspectos relativos a su formación, aproximación interdisciplinaria, y su trabajo colaborativo y comparado. Además, ambos esbozan reflexiones iniciales en torno a las particularidades de los procesos de diversidad y convivencia en la ciudad de Santiago; reflexiones basadas en observaciones y discusiones llevadas a cabo durante una estadía académica en Chile.
Lithological, sedimentological, ichnological, and palynological analysis of 37 conventional core intervals from 15 wells, offshore Labrador (Newfoundland and Labrador) and southeast Baffin Island (Nunavut)
Authors: Dafoe L T , Williams G L
Published: July 2020

The Labrador Sea began forming during rifting between Greenland and North America in the Early Cretaceous, resulting in grabens and half grabens infilled with syn-rift sediments. These strata were later draped during a sag-basin phase in the Late Cretaceous.
Seafloor spreading was initiated in the Maastrichtian, but was regionally taking place by the Paleocene, and the Labrador margin was subsequently overlain by a thick Cenozoic sedimentary wedge. To refine the understanding of this stratigraphic succession, conventional core intervals from exploration
wells were analyzed to reassess the biostratigraphy and depositional paleoenvironments. Findings are based on lithological, sedimentological, ichnological, and palynological studies of 37 core intervals from 15 wells along the Labrador margin and southeast Baffin Shelf. Five cores consist of
gneissic to granitic Precambrian basement rocks and three are from the Early Cretaceous Alexis Formation basalts, for which general descriptions are provided. The 14 cores from the Bjarni Formation are Barremian to Albian-Cenomanian and represent mostly marginal marine settings. Eight cores from the
Upper Cretaceous Markland Formation are early Campanian to Maastrichtian and represent shoreline (Freydis Member), shelf, and slope settings. Three cored intervals from unnamed Paleocene basalt flows from the northern part of Saglek Basin are also evaluated. The youngest four core intervals are from
the Gudrid and Cartwright formations of Selandian to earliest Ypresian age and represent tidal channel, deltaic, and shoreface settings. Overall results form the basis for future work, delineating the nature and age of stratigraphic horizons and packages along the Labrador
margin.
Preparation and sorption property study of Fe3O4/Al2O3/ZrO2 composite for the removal of cadmium, lead and chromium ions from aqueous solutions
Authors: Tsegaye Fekadu , Taddesse Abi M. , Teju Endale , Aschalew Minbale
Published: July 2020

Fe-Al-Zr ternary mixed oxides composite was synthesized via co-precipitation method for the removal Pb(II), Cd(II) and Cr(VI) ions from aqueous solutions. The as-synthesized materials were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscope hyphenated with energy dispersive X-ray diffraction (SEM-EDX) and Fourier transform infrared (FTIR) techniques. The pH at the point of zero charge (pHpzc) of the sorbent and effect of ionic strength on sorption were also determined. The batch tests were conducted to optimize the various sorption parameters such as pH, adsorbent dose, contact time, speed of agitation and initial metal concentration. The experimental results showed that the adsorbed amounts of Pb(II), Cd(II) and Cr(VI) tend to decrease with increase in pH. Freundlich isotherm model fits better the equilibrium data for the adsorbent. Kinetic data correlated better with both pseudo first order and pseudo second order kinetic models. The spontaneous nature of the adsorption process was also confirmed from thermodynamic grounds. The nanosized adsorbent exhibited an adsorption efficiency of 96.65%, 96.55% and 97.2% for Cd(II), Cr(VI) and Pb(II), respectively, at optimum condition. Experimental results showed that the nanocomposite was effective for the removal of the title heavy metals from aqueous solution.

 

Bull. Chem. Soc. Ethiop. 2020, 34(1), 105-121.

DOI: https://dx.doi.org/10.4314/bcse.v34i1.10
Synthesis of Ag-Fe3O4 nanoparticles for degradation of methylene blue in aqueous medium
Authors: Saeed Muhammad , Usman Muhammad , Muneer Majid , Akram Nadia , Haq Atta ul , Tariq Muhammad , Akram Fiza
Published: July 2020

Fe3O4 known as magnetite is one of the oxides of iron which plays a major role in various fields of sciences. Fe3O4 was synthesized by precipitation method using NH3.H2O, FeCl2.4H2O and FeCl3.6H2O as precursor materials. For synthesis of 5% Ag-Fe3O4, the green synthetic method was used for immobilization of Ag nanoparticles on Fe3O4 using leaves extract of Calotropis gigantea plant. The synthesized Fe3O4 and 5% Ag-Fe3O4 were employed as catalyst in degradation of methylene blue. The photo catalytic activity of Fe3O4 was remarkably enhanced by doping of Fe3O4 with Ag nanoparticles. Advanced instrumental techniques including XRD, EDX, TGA and SEM were used for characterization of synthesized particles. The immobilization of Ag on Fe3O4 enhanced the photo degradation of methylene blue from 40 to 72% at 40 °C which confirms that 5% Ag-Fe3O4 is an active catalyst for treatment of dye contaminated water. Ag-Fe3O4 exhibited almost same catalytic activity in two successive cycles.

 

Bull. Chem. Soc. Ethiop. 2020, 34(1), 123-134. 

DOI: https://dx.doi.org/10.4314/bcse.v34i1.11
Hexavalent chromium reduction from real electroplating wastewater by chemical precipitation
Authors: Verma Bharti , Balomajumder Chandrajit
Published: July 2020

The immense use of chromium in the electroplating process leads to the discharge of hexavalent chromium in its effluent. Since Cr(VI) is highly toxic, its exposure poses an acute risk of health. On the contrary, Cr(III) which is naturally occurring, is much less toxic than Cr(VI). Therefore the easiest way to deal with Cr(VI) is to reduce it into its trivalent form. Exhaustive chemical analysis was done to reduce Cr(VI) to Cr(III) by using sodium metabisulfite (Na2S2O5) and ferrous sulfate (FeSO4). And after the reduction process, precipitating agents such as (Ca(OH)2), (NaOH) and a combination of the two were used to precipitate Cr(III) as hydroxides. Various parameters were varied and optimized. It was observed that the % Cr(VI) reduction increased from 88% to 99.97% when the dosage of sodium metabisulfite increased from 40 mg/L to 100 mg/L at a pH of 2. The maximum removal of 98.2% was achieved by using the combination of Ca(OH)2 + NaOH at a pH of 9.

 

Bull. Chem. Soc. Ethiop. 2020, 34(1), 67-74.

DOI: https://dx.doi.org/10.4314/bcse.v34i1.6
Selective transportation of molybdenum from model and ore through poly inclusion membrane
Authors: Ali Nauman , Naz Nasiha , Shah Ziarat , Ali shah Anwar ul Haq , Khan Adnan , Nawaz Rubila
Published: July 2020

The extraction of molybdenum from the aqueous solution through poly inclusion membrane (PIM) containing tri-caprylylmethylammonium chloride (Aliquat-336) as a carrier has been investigated. A solution of molybdenum in phosphoric acid was used as a feed side while sodium hydroxide was used as stripping reagent. The results indicate that maximum flux value was obtained at 0.16 M Aliquat-336. Increase in H3PO4 concentration from 0.05 to 1.5 M results into an increase in molybdenum ions. The maximum flux of 3.00×10−6 mol/m2s through PIM was found at 1.5 M H3PO4. The optimized conditions were applied for removal of Mo(VI) from ore and more than 97 % Mo(VI) was extracted.

 

Bull. Chem. Soc. Ethiop. 2020, 34(1), 93-104.

DOI: https://dx.doi.org/10.4314/bcse.v34i1.9
Physicochemical properties and sensory attributes of local snacks fortified with powdered fish processing by-products and an underutilised fish species
Authors: Abbey L. , Glover-Amengor M. , Hagan L. , Mboom F. P.
Published: July 2020

Fish processing by-products and small pelagic fish could provide minerals and protein in diets of vulnerable populations as these could be more affordable than seafood. The study objectives were to determine the proximate nutrient content of tuna processing by-products and burrito fish and also assess the acceptability of fish powder-fortified local carbohydrate snacks. Tuna trimmings, gills, frames and burrito were dried at 55oC for eight hours to moisture levels of 4.8% (trimmings), 8.9% (frames), 6.8% (gills) and 6.9% (burrito). The products were milled and incorporated at varying levels into four local snacks namely: mpotompoto, yakayake, abolo and yam balls. Proximate nutrient levels of both fortified and non-fortified snacks were determined by Official Methods of Analysis (AOAC). Protein contents of mpotompoto-fortified fish products ranged from 3.75% to 8.5%. Ash also ranged from 1.12% to 5.54%. The control contained 1.17%. Acceptability tests were conducted on the fortified snacks using a 5-point hedonic scale. On the whole, fortified products showed significantly higher levels of protein and ash over the non-fortified snacks. Acceptance of the snacks by pupils (11-12) years was high enough to warrant incorporation of the fish powders into a school lunch menu.
Prevalence and correlates of prehypertension and hypertension among adults in Delta State, Nigeria: a cross-sectional community-based study
Authors: Umuerri Ejiroghene M. , Aiwuyo Henry O.
Published: July 2020

Background: There are indications that prehypertension precedes hypertension. Like hypertension, it is associated with increased cardiovascular risk.Objective: To determine the prevalence, awareness and correlates of prehypertension and hypertension among adults in Delta State, Nigeria.

Methods: This was a cross-sectional study. We recruited adults aged ≥18 years from two communities in Delta State, Nigeria, using the multi-stage sampling technique. The study instrument was a modified WHO-STEPS questionnaire.Prehypertension and hypertension were defined using the JNC-7 criteria. Ethical approval was obtained before the recruitment of participants.

Results: Of the 852 adults studied, the mean (±SD) age was 42.64 (±16.07) years, females (55.9%) and urban dwellers (55.8%). The prevalence of prehypertension and hypertension were 42.5% and 29.3%, respectively; both were higheramong urban dwellers. The peak age-group for prehypertension and hypertension were 25-34 and 35-44 years, respectively. Awareness of hypertension was low; 12.0% (102/852). Blood pressure category significantly correlatedwith age, body mass index, place of residence, level of education, employment status and fruit intake.

Conclusion: The prevalence of prehypertension and hypertension in this study were high. Based on the premise that prehypertension is a precursor of hypertension and occurred more among youths, the higher prevalence of prehypertensiongives an inkling to rising prevalence of hypertension.

Keywords: Prehypertension, hypertension, adults, Nigeria, WHO STEPS

Funding: Nil
Self-reported adherence to highly active antiretroviral therapy in a tertiary hospital in Nigeria
Authors: Eribo Ekiuwa V. , Adeleye Omokhoa A.
Published: July 2020

Background: Non-adherence to highly active antiretroviral therapy (HAART) favours drug resistance and wastes resources. These have negative implications for personal and public health.

Objective: To assess adherence levels, the associated factors and its association with increase in CD4 cell count in people living with HIV (PLHIVs).

Methods: In a cross-sectional survey, systematically selected adult PLHIVs attending a tertiary hospital in Nigeria self-reported their 28-day adherence to HAART and reasons for missing doses using an interviewer-administered questionnaire. Their 6-month difference in CD4 cell count was also assessed.

Results: The participants totalled 425. Their mean age was 38.6 (SD, 10.1) years and 309 (72.7%) had secondary or tertiary education. The 28-day mean adherence level was 96.8% (SD, 7.9%) and 354 (83.3%) participants had optimaladherence (≥ 95%). Socio-demographic characteristics, side effects and having human reminders were not associated with adherence level, but 100% adherence level since placement on HAART was positively associated with a 6-monthincrease in CD4 cell count (p < 0.01; OR = 1.87, 95%CI = 1.21 – 2.89). Reasons given by 156 respondents for missing doses included being too busy, 100 (64.1%), forgetting, 85 (54.5%) and sleeping off, 42 (26.9%).

Conclusion: Mean adherence was high and the majority of participants had optimal adherence. “Never missing a dose” was associated with improved CD4 cell counts, indicating better prognosis. Socio-demographic factors, side effects and human reminders were not associated with an increase in adherence. However, as there is no evidence that adherence improvement measures are detrimental, their use is still recommended.

Keywords: Medication adherence, HAART, HIV, drug resistance, Nigeria,

Funding: None declared
Midwives’ and Medical professionals’ perspectives of collaborative practice at Queen Elizabeth Central Hospital Maternity Unit, Malawi: The discovery phase of an appreciative inquiry project
Authors: Chodzaza Elizabeth
Published: July 2020

BackgroundThis paper reports on part of a larger study, the aim of which was to develop an intervention to collaboratively develop innovative strategies to promote effective collaborative practices among midwives and medical professionals working in intrapartum care unit. Collaborative practice is a critical marker for success in improving quality of maternity care. To date, there has been limited exploration of collaborative practices between midwives and medical professionals working in intrapartum care from the African perspective. Aim This paper reports findings of the discovery phase of appreciative inquiry (AI) set out tounderstand the perspectives of midwives and medical professionals on collaborative practices at Queen Elizabeth Central Hospital labour and delivery ward in Malawi. MethodsThe study used an exploratory qualitative approach framed in an Appreciative Inquiry theoretical perspective. Appreciative Inquiry consists of four phases :(discovery, dream, design and destiny).The discovery phase consisted of 16 in-depth interviews and 2 focus group discussions among purposively selected midwives (4 nurse midwives, 2 midwifery unit matrons) and medical professionals (2 obstetricians, 4 registrars, 2 intern doctors, 2 clinical officers) working in the labour ward. All interviews and discussions were audiotaped and transcribed verbatim. Data were analysed using thematic analysis. ResultsFive dominant themes emerged: collaborative breakdown, benefits of collaboration, the importance of positive and respectful attitude, barriers to effective collaborative practices and strategies to improve collaborative practice. Conclusion/RecommendationsAligning the perspectives of the members of the two disciplines is significant to effective implementation of collaborative intrapartum care. Participants demonstrated that there is increased parallel working of midwives and doctors at QECH. This is not professionally healthy. Therefore, putting together the viewpoints of the professions to create a mutually agreeable professional framework of collaborative intrapartum practice is significant. Additionally, there is an obvious need to address the professional concerns of both disciplines.
Emergency and critical care services in Malawi: Findings from a nationwide survey of health facilities
Authors: Kayambankadzanja Raphael
Published: July 2020

BackgroundGlobally, critical illness causes up to 45 million deaths every year. The burden is highest in low-income countries such as Malawi. Critically ill patients require good quality, essential care in emergency departments and in hospital wards to avoid negative outcomes such as death. Little is known about the quality of care or the availability of necessary resources for emergency and critical care in Malawi. The aim of this study was to assess the availability of resources for emergency and critical care in Malawi using data from the Service Provision Assessment (SPA).MethodsWe conducted a secondary data analysis of the SPA – a nationwide survey of all health facilities. We assessed the availability of resources for emergency and critical care using previously developed standards for hospitals in low-income countries. Each health facility received an availability score, calculated as the proportion of resources that were present. Resource availability was sub-divided into the seven a-priori defined categories of drugs, equipment, support services, emergency guidelines, infrastructure, training and routines.ResultsOf the 254 indicators in the standards necessary for assessing the quality of emergency and critical care, SPA collected data for 102 (40.6%). Hospitals had a median resource availability score of 51.6% IQR (42.2-67.2) and smaller health facilities had a median of 37.5% (IQR 28.1-45.3). For the category of drugs, the hospitals’ median score was 62.0% IQR (52.4-81.0), for equipment 51.9% IQR (40.7-66.7), support services 33.3% IQR (22.2-77.8) and emergency guidelines 33.3% IQR (0-66.7). SPA did not collect any data for resources in the categories of infrastructure, training or routines. ConclusionHospitals in Malawi lack resources for providing emergency and critical care. Increasing data about the availability of resources for emergency and critical care and improving the hospital systems for the care of critically ill patients in Malawi should be prioritized.
Knowledge and attitude towards mental disorders among adults in an urban community in south-west Nigeria
Authors: Mojiminiyi Iyanuoluwa
Published: July 2020

BackgroundMental disorders are one of the most ignored public health issues worldwide. However, the burden associated with mental disorders is ever increasing and poses a major threat to health, social interactions and the economy of both developed and developing countries.Aim To assess the knowledge of adults residing in an urban local government area in Lagos, south-west Nigeria, with regards to mental health and investigate their attitudes towards this condition.Methods This was a descriptive cross-sectional study. Multi-stage sampling was used to select 242 adults who were subsequently interviewed with a structured questionnaire. Data was collected and analysed using Epi Info statistical software version 7. Associations between socio-demographic variables and the knowledge and attitudes of subjects with regards to mental disorders were assessed using chi-square tests at a significance level of 0.05. ResultsAlmost all respondents (95.5%) in this study were aware of mental disorders while 31.0% were related to someone with a mental disorder. Approximately half of the respondents (51.2%) had poor knowledge of mental disorders while the majority (90.0%) had positive attitudes. There was a significant and positive association between having a relative with a mental disorder and the level of knowledge (P=0.010).ConclusionAnalyses identified knowledge gaps in the community in terms of mental disorders in the community. We recommend that health workers should develop ways to educate the community with regards to the causes, symptoms, effects and treatment options for mental disorders.
Autoeficacia en estudiantes universitarios: el rol del empoderamiento académico
Authors: Tumino Marisa Cecilia , Quinde Josué Mauricio , Lilian Noemí Casali  , Melissa Raquel Valega
Published: July 2020

La autoeficacia académica constituye un factor importante para el desempeño óptimo en la universidad. En el actual modelo de enseñanza- aprendizaje, el empoderamiento académico aparece como un proceso que facilita la adquisición de herramientas necesarias para desarrollar la autoeficacia. El empoderamiento del estudiante puede potenciar su accionar para mejorar sus habilidades, adaptarse y transformar su entorno.

El objetivo del estudio fue analizar la relación entre el empoderamiento académico y la autoeficacia de los estudiantes universitarios. Para ello se analizaron los datos de 440 estudiantes de diferentes años y carreras, mediante tres escalas tipo Likert adaptadas al ámbito académico. Se aplicaron correlaciones de Pearson y ecuaciones estructurales (SEM) a las variables estudiadas. Los resultados han mostrado que el Empoderamiento Psicológico desempeña un papel mediador entre el Empoderamiento Estructural y la Autoeficacia. Estos resultados destacan el papel trascendente de las condiciones estructurales que deben sostener el proceso de aprendizaje.
Control empresarial del uso de dispositivos digitales en el ámbito laboral desde la perspectiva del derecho a la protección de datos y a la intimidad
Authors: López Balaguer Mercedes , Ramos Moragues Francisco
Published: July 2020

Los avances tecnológicos no sólo han permitido una evolución en los procesos productivos o en la forma organizativa y de trabajar de las empresas, sino que también han posibilitado que éstas escojan nuevas formas y métodos de supervisión de la actividad laboral más invasivos, que, en ocasiones, entran en colisión con los derechos fundamentales de los trabajadores, entre ellos, el derecho a la protección de datos y el derecho a la intimidad. La vigente Ley de Protección de Datos destina algunos preceptos a regular el control y acceso por parte de la empresa a los dispositivos digitales facilitados al trabajador. El presente trabajo analiza estos preceptos y los rasgos más destacados de su régimen jurídico.
The Effect of 'Fish Diversity' Book in Kampar District on the Learning Motivation and Obstacles of Kampar High School Students through Online Learning during the COVID-19 Period
Authors: Yustina Yustina , Halim Lilia , Mahadi Imam
Published: July 2020

The study aims to analyze the effect of the fish diversity book in Kampar District on the learning motivation and obstacles of Kampar High School students through online learning during the COVID-19 period. This type of research is a quasi-experimental study with research subjects in class XI SMA Kampar (Kampar High School). In its implementation, students were given a motivational questionnaire in the beginning, after that they were given the task of studying the types of fish in Kampar through the book files of fish diversity in Kampar District through online learning. After online learning, the post-test was given using a questionnaire evaluation of the motivation and online learning obstacles questionnaire. Parameters: learning motivation with five indicators, ten indicators of online obstacles. Motivation data collection using pre-test and post-test. Data is presented and analyzed descriptively. The results obtained an average score of post-test student learning motivation (77.7) increased compared to before studying diversity book (65.9) with an N-gain index of 0.34, 74% of respondents said online learning was more effective, 50% of respondents stated the ordinary school is better than online learning. The implementation of fish species diversity books through online learning is effective in increasing student learning motivation, but it is less effective in motivating desires, appreciation, and not being attractive enough. The obstacles of online learning at Kampar High School include internet network facilities and field practicum during the COVID-19 period.Â
Global successful experiences of the health tourism brand and presentation of a native model
Authors: Afsharifar Amin
Published: July 2020

The current study aims to benchmark the global successful experiences of health tourism branding and presenting its native pattern. This study is analytical-descriptive in nature and practical approach in terms of the target sought. The questionnaire was designed to measure the effective variables on health tourism branding. A researcher-made questionnaire, whose dimensions and indicators were based on the literature and research background, was used to measure the dependent variable of the research. Acer brand value questionnaire was used for assessing the dependent variable of the research. The statistical population of this research is the professors of the medical sciences universities and tourism and marketing management group and the directors and assistants of the Cultural Heritage, Handicrafts and Tourism Organization of Fars and Bushehr provinces that regarding the lack of access to all members of the research community, sampling was done by available sampling. Finally, 87 valid questionnaires were obtained. After examining the research model using the path analysis method, the findings showed that all paths between the research variables were confirmed at 95% confidence level and were significant. This means that policy making, infrastructure, marketing, communication and information, medicine and health have a positive and significant impact on health tourism branding. However, the findings indicated that the highest path coefficient for the relationship between the infrastructure and branding of health tourism is 0.365.