What grounded theory is ... a critically reflective conversation among scholars

Grounded theory (GT) is taught in many doctoral schools across the world and exemplified in most methodological books and publications in top-tier journals as a qualitative research method. This limited view of GT does not allow full use of possible resources and restrains researchers’ creativity and capabilities. Thus, it blocks some innovative possibilities and the emergence of valuable theories, which are badly needed. Therefore, understanding the full reach and scope of GT is becoming urgent, and we brought together a panel of established grounded theory scholars to help us in this endeavor through a reflective conversation

Comparative Sorption of Methylene Blue onto Hydrophobic Clays

Chemical modifications of clay to remove methylene blue (MB) from aqueous solutions at room temperature were compared. Natural bentonite (NC) was modified by cation exchange with hexadecyltrimethylammonium chloride (HC), bencyltriethylammonium chloride (BC), and tetramethylammonium chloride (TC) to reverse the surface polarity of the hydrophilic bentonite. The adsorption of MB was studied and fitted by the adsorption theories of Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin. Equilibrium parameters were calculated, indicating that chemical modification did not improve the adsorption, due to the electrostatic adsorption mechanism. Specific surface area was determined, reporting the following trend: NC \u3e TC \u3e BC \u3e HC. Isotherms show that TC is the best modified clay for the adsorption of MB with a capacity of 217 mg/g. Adsorbents were characterized by SEM and the determination of their point zero charge, indicating a charge reversal at pH 9.5 and a heterogeneous surface that is optimum for the adsorption of molecules and ions onto their surfaces

Room-temperature Operation of Low-voltage, Non-volatile, Compound-semiconductor Memory Cells

Whilst the different forms of conventional (charge-based) memories are well suited to their individual roles in computers and other electronic devices, flaws in their properties mean that intensive research into alternative, or emerging, memories continues. In particular, the goal of simultaneously achieving the contradictory requirements of non-volatility and fast, low-voltage (low-energy) switching has proved challenging. Here, we report an oxide-free, floating-gate memory cell based on III-V semiconductor heterostructures with a junctionless channel and non-destructive read of the stored data. Non-volatile data retention of at least 104 s in combination with switching at ≤2.6 V is achieved by use of the extraordinary 2.1 eV conduction band offsets of InAs/AlSb and a triple-barrier resonant tunnelling structure. The combination of low-voltage operation and small capacitance implies intrinsic switching energy per unit area that is 100 and 1000 times smaller than dynamic random access memory and Flash respectively. The device may thus be considered as a new emerging memory with considerable potential

Rebar corrosion in mortars with high limestone filler content

Purpose – This research aims to study the influence of limestone filler on rebar corrosion. Design/methodology/approach – Mortar samples containing 35% calcareous filler and with a rebar inserted in the axis, were cast. Specimens were cured at the open air and during 28 days in lime water. After curing, they were submerged in two electrolytes (tap water and 3% NaCl) and corrosion parameters (corrosion potential and corrosion current) were monitored over time by d.c. techniques. Simultaneously, electrochemical noise measurements were carried out. After corrosion tests, rebars were pulled out by lateral compression, and their surface observed by scanning electron microscopy. Findings – In general, carbonate additions impaired mortar protective properties, especially in the presence of chloride and changed the nature of the protective layer on rebars. The curing process did not introduce significant differences except for mortars with a high water cement ratio cured in lime water for which the beneficial effects of the simultaneous presence of carbonate and lime in the pore solution could be appreciated. The role of carbonate additions is to provide carbonate anions to passivate rebars. This passivation process caused corrosion rates not to be so high. Carbonate anions also deposited on oxide spots which were rendered passive but this process was not uniform. Certain areas on the rebar underwent intense carbonation while others showed increased corrosion rates. Originality/value – There are not many corrosion studies about the influence of limestone filler on rebars corrosion. Particularly, this paper deals with mortars containing high percentages of carbonate additions. Results showed that the presence of this type of admixture changes the structure of the passive layer and, sometimes, may increase corrosion rates.Centro de Investigación y Desarrollo en Tecnología de Pintura

Libres de humo: efectividad de un programa de cesación tabáquica en un Centro de Salud Comunitario de la Ciudad Autónoma de Buenos Aires

Introducción. El consumo de tabaco representa un importante desafío para la salud pública debido a su alta incidencia y mortalidad, y es el principal factor de riesgo modificable para desarrollar enfermedades crónicas no transmisibles. La Residencia de Medicina General y Familiar del Hospital General de Agudos Dr. Teodoro Álvarez desarrolló un programa de cesación tabáquica en el Centro de Salud y Acción Comunitaria N°34, que forma parte desde 2012 del Programa de Prevención y Control del Tabaquismo del Ministerio de Salud del Gobierno de la Ciudad de Buenos Aires, Argentina. Objetivo. Documentar los resultados de la eficacia de este programa y explorar las variables relacionadas con la probabilidad de éxito y recaída. Materiales y métodos. Estudio cuantitativo, de corte transversal analítico, con datos obtenidos de historias clínicas electrónicas entre 2017 y 2020. Fueron incluidos los pacientes que consultaron al menos en dos ocasiones al programa de cesación tabáquica y establecieron un día D al menos 30 días antes del abandono del consumo de tabaco. La eficacia terapéutica fue definida como haber permanecido al menos seis meses sin fumar, y la recaída, como el reinicio de consumo del tabaco luego de haber logrado 24 horas de abstinencia con fecha posterior al día D. Resultados. De 59 pacientes, 24 (40,7%) lograron la eficacia terapéutica, de los cuales 5 (20,8 %) presentaron recaídas. De los 35 pacientes que no lograron alcanzar la etapa de mantenimiento, 30 (85,7%) recayeron durante las primeras ocho semanas. El sexo masculino y el consumo de tabaco superior a 20 paquetes-año mostraron una mayor correlación con las recaídas. Conclusiones. El programa presentó una eficacia terapéutica del 40,7% en el periodo evaluado. Se encontraron asociaciones entre una mayor eficacia terapéutica y ciertas características de los pacientes, pero se requieren más estudios para confirmar esta hipótesis

Examining associations Between School-Level Determinants and the Implementation of Physical activity Opportunities

School-based physical activity (PA) opportunities can help students engage in greater amounts of daily PA, meet PA guidelines, and lead to improved health and educational outcomes. However, we do not completely understand the organizational challenges to implementing these opportunities successfully. This exploratory study examined associations between school-level determinants and the implementation of school-based PA opportunities. We analyzed cross-sectional survey data from schools (n = 46) participating in the Healthy Zone School Program (HZSP) (Dallas, Texas, USA) during 2019-2020. Respondents completed an electronic survey that included measures of school-level determinants (e.g. culture, leadership, priority) and the implementation of school-based PA opportunities. We used linear regression models to examine associations between determinants and implementation outcomes (number of PA opportunities delivered, perceived overall success of each PA program/activity used). After adjusting for campus type (i.e. elementary, middle, high, K-12), student race/ethnicity, and percentage of economically disadvantaged students, no constructs were associated with the number of PA opportunities implemented. Linear regression models suggest access to knowledge and information (β = 0.39, P = .012, 95% CI = 0.24-1.44) and implementation climate (β = 0.34, P = .045, 95% CI = 0.02-1.59) were positively associated with the success of school-based PA opportunities. Our findings provide suggestive evidence that access to knowledge and information and a supportive school climate may improve the overall success of PA opportunities provided to students. Future research should examine additional school-level determinants to understand their importance to implementation and inform the development of strategies to improve schools\u27 capacity for implementing PA opportunities successfully

Dispersal limitations and historical factors determine the biogeography of specialized terrestrial protists

Recent studies show that soil eukaryotic diversity is immense and dominated by micro-organisms. However, it is unclear to what extent the processes that shape the distribution of diversity in plants and animals also apply to micro-organisms. Major diversification events in multicellular organisms have often been attributed to long-term climatic and geological processes, but the impact of such processes on protist diversity has received much less attention as their distribution has often been believed to be largely cosmopolitan. Here, we quantified phylogeographical patterns in Hyalosphenia papilio, a large testate amoeba restricted to Holarctic Sphagnum-dominated peatlands, to test if the current distribution of its genetic diversity can be explained by historical factors or by the current distribution of suitable habitats. Phylogenetic diversity was higher in Western North America, corresponding to the inferred geographical origin of the H. papilio complex, and was lower in Eurasia despite extensive suitable habitats. These results suggest that patterns of phylogenetic diversity and distribution can be explained by the history of Holarctic Sphagnum peatland range expansions and contractions in response to Quaternary glaciations that promoted cladogenetic range evolution, rather than the contemporary distribution of suitable habitats. Species distributions were positively correlated with climatic niche breadth, suggesting that climatic tolerance is key to dispersal ability in H. papilio. This implies that, at least for large and specialized terrestrial micro-organisms, propagule dispersal is slow enough that historical processes may contribute to their diversification and phylogeographical patterns and may partly explain their very high overall diversity

Visión general de las percepciones regionales sobre el rol de la educación superior para el desarrollo humano y social

Nuestro informe ha estudiado en su Parte I temas globales seleccionados acerca del rol de la educación superior para el desarrollo humano y social. Este trabajo es una síntesis de las perspectivas regionales -África Subsahariana, Estados Árabes, Asia y el Pacífico, Europa, América del Norte y América Latina y el Caribe- acerca del rol de la educación superior para el desarrollo humano y social basado en la contribución de los autores en cinco áreas claves: una de ellas es el estado de la educacion superior en cada región desde la celebración de la Conferencia Mundial sobre Educación Superior (CMES, 1998); y otra de las cuatro áreas clave se refiere a los posibles roles futuros, estrategias y acciones de la educación superior para promover el desarrollo humano y social.Peer Reviewe