bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the Slope Angle and Its Classification on Landslide
Authors: Çellek Seda
Published: May 2020

Abstract. The phase after the determination of the landslide area in landslide susceptibility studies is the selection of methods and parameters to be used. Approximately 1500 randomly selected publications show that it is necessary to select a parameter based on the area. Research has shown that the parameter of slope is greatly preferred. There is nearly consensus of opinion among researchers regarding the use of the parameter. The research included the definition of slope made by different researchers, the advantages and disadvantages of the use of the parameter, different classifications that are used, the formation intervals of landslides, their use together with other parameters, and its effect on the formation of landslides. Classifications were studied based on the slope values at which landslides. Generally, automatic slope classifications are used in the preparation of landslide maps. There isn’t standard in parameter maps. Therefore, there isn’t class range that is referenced when preparing slope maps. In this study, preferred class ranges and slope values where landslides occur were determined in the literature. 40 landslides area has been selected in Turkey. These were evaluated in the slope classes determined according to the literature. The results compared with the literature were found to be compatible.
Potential Effects Immunomodulators on Probiotics in COVID-19 Preventing Infection in the Future. A Narrative Review
Authors: Adnan Muhammad Luthfi , Dewi Miranti D.
Published: May 2020

After the outbreak in December 2019, Coronavirus Disease (COVID-19) has become a global health problem because of its rapid spread throughout the world. To date, there are no effective therapies to treat or prevent COVID-19 infection. Probiotic bacteria are widely used to prevent gastrointestinal infections by modulating intestinal microbiota. Therefore, this literature review focuses on the potential possessed by probiotic bacteria for the prevention of future COVID-19 infections. Information was extracted from PubMed and Google Scholar using the keywords: "COVID-19", "immunomodulator", "inflammation", and "probiotic" and synthesize in a narrative review. The results showed that probiotic bacteria have immunomodulatory activity that can increase immunity against pathogens by regulating the immune system through modulation of intestinal microbiota and interactions with the lymphatic system in the digestive tract. The ability of the immune system regulation by probiotic bacteria has the effect of increasing the body's defense mechanisms against pathogens that infect the respiratory tract. However, further evidence is still needed regarding the effect of probiotic immunomodulators in combating future COVID-19 infections.
La eventualidad como norma básica del empleo agrícola en un territorio del sur de Europa
Authors: Ramírez Melgarejo Antonio J.
Published: May 2020

El objetivo principal de investigación fue analizar como las clases populares se adaptan a la eventualidad como norma laboral básica en el sector agrícola. A partir de tres estudios de caso inducimos como lo/as trabajadore/as viven la temporalidad inherente al trabajo agrícola. La investigación se realizó en la Vega Alta del Río Segura (Murcia), un territorio prototípico del sur de Europa cuyo modelo productivo ofrece empleos en sectores de baja productividad. Debido a sus particulares características diseñé una metodología de investigación cualitativa para adentrarnos en los intersticios del mercado de trabajo local. Se realizaron 42 entrevistas guionizadas en profundidad, inmersiones etnográficas y observación participante en numerosas ocasiones, combinadas con fuentes estadísticas secundarias. La principal conclusión fue que el trabajo agrícola en el sureste está caracterizado por la eventualidad, la incertidumbre y la disponibilidad, lo que condiciona las estrategias de adaptación de las clases populares a la relación salarial discontinua.
El análisis de clase marxista en la era de la precariedad y la flexibilidad
Authors: Aja Valle Jaime , Sánchez Iglesias Eduardo
Published: May 2020

Las transformaciones del trabajo de las últimas décadas, caracterizadas por la precariedad y la flexibilización, suponen un desafío para el análisis de clase y para el análisis de raíz marxista. El objetivo de este artículo es construir, en debate con Marx, una propuesta de análisis que permita abordar estos cambios sociales. Para ello se revisan el concepto de clase de Marx, complejizándolo, y aproximaciones contemporáneas que hacen uso de esa concepción en el análisis de la sociedad actual. Marx ofrece una concepción de clase interesante y útil pues enmarca el proceso de construcción de la clase social en un marco relacional de lucha política, económica y cultural. Consideramos que los procesos de transformación del trabajo hacen que cobren un mayor interés los análisis de clase centrados en las relaciones sociales de dominación y explotación.
Online Personal Learning Networks for Older Adults: Impacts on Social and Mental Well-Being
Authors: Morrison Dirk
Published: May 2020

This study investigated retired older adults (age 55+) who use the Internet to facilitate their informal, self-directed learning by creating and maintaining their online personal learning networks (oPLNs), and how such use impacts their personal, social, and mental well-being.  Guiding this examination were particular research questions that specifically queried the perceived value of their oPLNs to activate and self-direct their informal learning. The web-conferencing tool WebEx was used to conduct four synchronous online focus groups allowing a total of 15 voluntary, geographically dispersed participants from across Canada to share their experiences and insights. A thematic analysis of the focus group transcripts revealed themes informing how oPLNs facilitated their informal learning goals and influenced participants’ personal valuing of their online activity.  As a component of results from the larger research study (Morrison, Litchenwald, & Krystkowiak, 2020; Morrison, Litchewald, & Tang, 2020; Morrison & McCutcheon, 2019)  , the findings presented, drawn from the online focus group qualitative data, indicated positive perceived valuing of their informal learning via their oPLNs as well as indications of favorable social and mental well-being outcomes. Interpretive speculation is provided regarding how these informal online learning experiences and oPLNs in particular, may point to a favorable impact on similar retired older adults’ personal, social, and mental well-being.
Barns erfaringer rundt mening og sammenheng i barnehagehverdagen. En analyse av tematisk innhold i samspillet mellom barn og barnehagelærer
Authors: Bergem Helen
Published: May 2020

Artikkelen bygger på en studie som har undersøkt hva barn i alderen 1– 3 år og barnehagelærere samspiller om i det daglige, og som har betydning for barns muligheter til å erfare sammenheng i hverdagen. Observasjonssekvenser av samspill er analysert over et tidskontinuum for å kunne identifisere hvordan det som kan fremstå som situert og av mer trivielt tematisk innhold i samspill er koblet til andre og mer abstrakte dimensjoner av barns institusjonskulturelle læring. Fire områder frem som representerer mer grunnleggende interesser i samspillet er analysert. Disse er: 1) Tidsperspektiver, 2) natur som grunnlag for handling, 3) relasjoner og følelser, og 4) kulturelle koder og regler. I artikkelen presenteres eksempler på disse tematiske områdene for å synliggjøre hvordan konkrete initiativ i samspillet, som ofte handler om materielle ting (klær, leker), er koblet til mer abstrakte fenomener. Diskusjonen handler om hvordan slike samspill representerer erfaringer av forutsigbarhet, belastningsbalanse og innflytelse, som er viktige betingelser for å oppleve sammenheng i tilværelsen, slik Aron Antonovsky beskriver det. Studien bidrar til å nyansere forståelsen av begrepet livsmestring i lys av det ansvaret som ligger hos ansatte som jobber med de yngste barna i barnehage.
Contabilidad de Costos I, base fundamental en el área disciplinar de Contaduría Pública y Finanzas
Authors: Benavides Fuentes Juan Carlos
Published: May 2020

El perfil de Contaduría Pública y Finanzas, abarca cuatro áreas disciplinares: Contabilidad, Finanzas, Costos y Auditoría. Por lo tanto, es necesario poseer una base teórica y práctica en la Contabilidad de Costos I como base fundamental para las asignaturas subsecuentes del área disciplinar de Costos. En las dos primeras unidades de esta asignatura, se establecen los cimientos necesarios para comprender como funciona la contabilidad de costos y posteriormente, estos conocimientos se deben adaptar a los sistemas de costos abordados en las asignaturas subsecuentes. Para lograr este propósito, se implementaron estrategias de enseñanza y aprendizaje tales como: fabricar productos, analizar el flujo de la contabilidad de costos, utilizar un catálogo de cuentas y reflexionar con los estudiantes sobre la importancia de la asignatura, a fin de obtener el éxito académico en las siguientes asignaturas de costos, lográndose a partir de esto un mayor interés por alcanzar un aprendizaje significativo y aplicable.
Importancia de los ingresos públicos en la economía nicaragüense
Authors: Mayrena Bellorín Milton Ulises
Published: May 2020

Todos los países del mundo se ven en la necesidad de tener una organización administrativa bien definida para la administración de los ingresos públicos. Esta organización, es la encargada de planificar, organizar, dirigir y ejecutar todas las acciones encomendadas a cada nación desde las diferentes instituciones. Para lograrlo, se debe de contar con ingresos para que todo lo planificado se pueda ejecutar. En el presente escrito, se hace un análisis sobre los ingresos públicos, su importancia, y su implicancia en el desarrollo económico del país. Los tributos representan los principales ingresos para el estado, entre ellos se cuentan los impuestos, tasas y contribuciones especiales que todos los ciudadanos nicaragüenses de forma directa o indirecta contribuyen a dichos recaudos. Todos los ingresos recaudados son administrados el Ministerio de Hacienda y Crédito Público, siendo el responsable de distribuir las partidas presupuestarias a cada institución pública para la ejecución de sus planes anuales.
¿Qué es el Fondo para Proyectos de Investigación (FPI) en la UNAN-Managua?
Authors: Sánchez Merlos Dalia
Published: May 2020

Las instituciones nicaragüenses de educación superior tienen como uno de sus objetivos esenciales desarrollar y fomentar la investigación científica como una estrategia fundamental para contribuir a la transformación de la sociedad. Este artículo describe el papel que ha desempeñado el Fondo para Proyectos de Investigación (FPI) de la Universidad Nacional Autónoma de Nicaragua, Managua (UNAN-Managua) para promover e incrementar la investigación en la Universidad. La población objeto de estudio estuvo compuesta por los proyectos que aplicaron y los adjudicados en las cuatro convocatorias del FPI (2015-2017, 2016-2018, 2017-2019, 2018-2020). De 233 proyectos recibidos se financiaron 127, de los cuales 66 proyectos se inscriben en el área investigativa de cambio climático, gestión ambiental y manejo de los recursos naturales. La modalidad con el mayor número de proyectos financiados fue la de Docentes-Investigadores. Las principales limitaciones han sido la tardanza de las rendiciones financieras, adquisición de insumos y la demora para la entrega de productos, sin embargo, el FPI se ha convertido en un instrumento importante para el fortalecimiento de la investigación en la UNAN-Managua, en correspondencia con los compromisos adquiridos en el Plan Nacional de Desarrollo Humano (PNDH) y los Objetivos de Desarrollo Sostenible (ODS).
Evaluación de metodologías de extracción de ADN de plantas recalcitrantes
Authors: Suazo Ubieta Taryn , Miranda Calero Samantha , Rivers Carcache Ena , Lacayo Romero Martha , Tenorio Juárez Daniel
Published: May 2020

La obtención ácido desoxirribonucleico (ADN) purificado es un punto clave para el desarrollo de técnicas moleculares que permiten caracterizar una especie en estudio. Las matrices vegetales constituyen una de las muestras de mayor complejidad debido a los compuestos químicos que la forman y que muchas veces difieren su concentración en dependencia de la variedad en estudio; este es el caso de muestras recalcitrantes de variedades de cacao (Theobroma cacao) y café (Coffea arabica) donde la pérdida de ADN puede incluso ocurrir en la maceración de las muestras por fenolización del material. En el presente estudio se evaluaron tres kits comerciales disponibles mediante los cuales se obtienen excelentes recobros para variedades no recalcitrantes, así como también modificaciones realizadas a los protocolos tradicionales de Doyle & Doyle (1987) y Doyle & Doyle (1990). Los resultados obtenidos confirmaron el efecto de la variedad y la especie sobre el método de extracción, y de igual manera, que los métodos modificados pueden presentar mayor recobro y pureza que los kits comerciales para algunas especies vegetales.
Auditoría ambiental del manejo de residuos sólidos de la ciudad de Granada, Nicaragua
Authors: Vega Aguirre Izamara Carolina
Published: May 2020

El estudio se enfoca en la realización de una auditoría ambiental que contribuirá al mejoramiento de  las prácticas ambientales en el servicio de recolección de residuos sólidos que ofrece la Alcaldía de  la ciudad de Granada,  diagnosticando todo el proceso de recolección, tratamiento y disposición final de los residuos sólidos no peligrosos generados, lo que permitirá  implementar un plan de acción y fortalecer el manejo de los residuos sólidos, a través de una guía de seguimiento de las acciones a cumplir al mejoramiento ambiental y una evaluación objetiva de los elementos del sistema de recolección, tratamiento y disposición final de los mismos, de esta manera se minimizarán o se pretende minimizar los riesgos de contaminación ambiental por la realización de actividades que por su naturaleza constituyen un riesgo potencial para el ambiente.
Low Level of 25(OH)D Aggravates Target Organ Damage of Elderly Type 2 Diabetes
Authors: Jiang Hongfeng , Peng Shaorong , Guo Zhangqiang , Huang Caihua , Zhang Jie
Published: May 2020

BACKGROUND: It is unclear about the association between vitamin D level and target organ damage in elderly patients with type 2 diabetes in China. Aim of this study was to investigate the relationship between vitamin D level and target organ damage in elderly patients with type 2 diabetes of Chinese population.

METHODS: A retrospective study was performed on 254 elderly patients with type 2 diabetes (148 males and 106 females). According to assay of 25-hydroxy vitamin D [25(OH)D], the participants were divided into a deficiency group (n=129), an insufficiency group (n=77) and a sufficiency group (n=48). The clinical indicators of target organ damages among these groups were analyzed, and multivariate logistic regression analysis was performed to predict the target organ damage.

RESULTS: Approximately 81.1% of patients were the low level of 25(OH)D with mean 25(OH)D below 30ng/ml. When compared with those in the sufficiency group, the level of left ventricular absolute mass index (LVMI), the morning urine albumin/uric creatinine ratio (ACR) and carotid intimal medial thickness (cIMT) increased significantly and creatinine clearance rate (CcR) decreased significantly in the deficiency group (P<0.05). The level of ACR and cIMT in the insufficiency group also increased significantly (P<0.05). There was a higher proportion in kidney, brain, artery and total target organ damage in the deficiency group or insufficiency group than those in the sufficiency group (P<0.05). Logistic regression analysis showed that low-level 25(OH)D  (< 30ng/ml) was independently associated with total target organ damage in patients with elderly type 2 diabetes (OR = 3.58; 95%CI: 1.60-8.02,P =0.002)

CONCLUSIONS: A condition of hypovitaminosis D is commonly present in Chinese patients with elderly type 2 diabetes. The low level of 25(OH)D may contribute to aggravate target organ damage of elderly type 2 diabetes.
Impact of Tax Revenue on Economic Development in Nigeria
Authors: Ewa Uket E. , Adesola Wasiu A. , Essien Etim N.
Published: May 2020

There has been conflicting preposition as to the extent of tax contribution to the development of Nigerian economy. This study is to determine the impact of taxation proceeds on the development of Nigerian economy. The study explored the impact of three tax income streams – Income tax from companies’ profits, income tax from petroleum companies profits  and Value Added Tax on economic development represented by Gross Domestic Product (at current basic prices) growth for the period 1994 to 2018. The study applied Ordinary Least Square statistical tool with the help of SPSS 20.0. The study revealed a positive relationship with a coefficient of determination of 99.2% of the variation in economic development attributable to the tax income streams studied. Also although the study revealed the existence of significant effect of taxes from companies’ profits and Value Added Tax on Gross Domestic Product Growth, there is little or no significant impact of taxes on profits of Petroleum companies on Gross Domestic Product growth in Nigeria due to restriction by Organization of Petroleum Exporting Countries production ceiling on Nigeria’s production/sales and the global price shocks of crude oil over the decade. Also the study revealed tax payers apathy to tax payment and presence of tax leakages due to corruption and administrative inefficiencies by the tax authorities.
An Unusual Cause of High Density Radiological Opacities
Authors: Chary Ravindra , Sneha Leo , Vishnukanth Govindaraj , Manju Rajaram
Published: May 2020

Introduction: Metallic mercury poisoning through intravenous injection is rare, especially as part of a suicide attempt. Diagnosis and treatment of the disease are challenging as clinical features are not specific. Material and metods: A 41-year-old male presented with dyspnea, fatigue, loss of weight, and loss of appetite over two months. Routine radiological examination by chest X-ray and CT showed randomly distributed high density opacities with Hounsfield units (HU) around 500 HU all over the body. The diagnosis was then confirmed with a urinary mercury concentration of > 1000 mcg/24 h. Results: The patient’s clinical condition was getting worse in spite of chelation therapy and hemodialysis. The patient eventually died because of respiratory failure. Conclusion: Early diagnosis and appropriate treatment are critical for intravenous mercury poisoning especially because there are no specific signs or symptoms. There should be a high level of suspicion in drug abusers. Treatment should involve the combined use of chelating agents and other treatments such as hemodialysis and plasma exchange in advanced clinical settings.
Curative Lobectomy in a Patient with Pulmonary Arteriovenous Fistula
Authors: Karuga Filip , Żychowicz Zuzanna , Rogut Magdalena , Gabryelska Agata , Białasiewicz Piotr
Published: May 2020

A 26-year-old Caucasian male was referred to the Sleep and Respiratory Disorders Centre with a past medical history of polycythemia and hypoxemia with chronic respiratory alkalosis [...]
Caecal Volvulus
Authors: K. Okeny Paul
Published: May 2020

Colonic volvulus is the third leading cause of large bowel obstruction. About 35% of these are located in the caecum. Though, relatively, a rare cause of obstruction, the incidence of caecal volvulus is steadily increasing at a rate of about 5% per year. Mortality due to caecal volvulus may be as high as 40% especially in the presence of gangrene and sepsis. Clinical presentation may be acute and fulminant or as a mobile caecum syndrome with intermittent abdominal pain. “Whirl,” “Coffee bean,” and “bird beak” signs seen on computed tomography are pathognomonic. Colectomy is the preferred treatment as it obviates any chance of recurrence. A conservative approach to colectomy such as limited ileocaecal resection and ileostomy formation in critically ill patients or in those with poor physiological reserve may be associated with better postoperative outcomes.
Multifetal Gestations
Authors: Kayar Ilkan
Published: May 2020

In recent years, multiple pregnancy rates have increased significantly. Twin pregnancy rate increased by 76% between 1980 and 2009, from 18.9 to 33.3 in 1000 births. Triplets and high-order multiple pregnancies have increased by 400% in the 1980s and 1990s. Two main reasons of this increase in the incidence of multiple pregnancies are: (1) maternal age at the time of conception, shifting to advanced ages where multiple pregnancies are more common and (2) a more common use of assisted reproductive techniques. The main problem in multiple pregnancies is spontaneous preterm delivery and associated neonatal morbidity and mortality. Although numerous attempts have been made to prolong the gestation period and improve outcomes, none of them have been effective. In this article, the complications encountered in multiple pregnancies will be summarized and evidence-based approaches that can be used in their management will be reported.
Blended learning i de praktisk-musiske fag set gennem et systematisk litteratur-review
Authors: Nortvig Anne-Mette , Gundersen Peter , Gynther Karsten , Akselsen Käte
Published: May 2020

Blended learning er i dansk sammenhæng et veletableret begreb, som betegner koblingen af fysiske undervisnings- og læringsrum med læringsrum online – en forståelse som i særlig grad er en udfordring for udvikling af blendede forløb til praktisk-musiske fag.  Med afsæt i en kritisk diskussion af traditionelle forståelser af blended learning undersøges andre forståelser og formater blandt andet udfoldet i et innovationsteoretisk perspektiv. I form af et litteraturreview af international forskning diskuteres følgende spørgsmål:  Hvordan kan undervisning i praktiske færdigheder i et blended learning format uden F2F kollaboration og delte sansemotorisk erfaringer udfoldes på nye måder med udgangspunkt i Systematisk Innovativ Tænkning?  Artiklen formidler resultaterne fra første del af et flerårigt empirisk forskningsprojekt, som følger udvikling, test og redesign af et nyt blended format for uddannelse og efteruddannelse af folkeskolelærere i de praktisk-musiske fag.
Festivales de cine y crisis sanitaria: pronósticos imposibles
Authors: Sánchez-Navarro Jordi
Published: May 2020

Pocas horas antes de la redacción de estas líneas, el Festival de Cannes, el encuentro cinematográfico más importante del mundo, emitía un comunicado oficial en el que anunciaba de que el aplazamiento inicialmente anunciado (de mayo a finales de junio) resultaba imposible de llevar a cabo. Además, en su nota dirigida a la prensa, la dirección afirmaba que, «en estos momentos, se hace difícil pensar que el Festival de Cannes pueda organizarse este año en su formato original».
The estimation of an anthropogenic depth boundary using the magnetic susceptibility method in Kogi State, North-Central Nigeria
Authors: Jatto Solomon Sunday , Musa Kizito O , Mojisola Usikalu R.
Published: May 2020

Magnetic susceptibility measurements remain one of the most reliable methods used to investigate the pollution of both surface and subsurface soil from metallic anthropogenic sources. Most of the geological rocks within the study area increase the susceptibility of the soil; however, knowing the natural background susceptibility of the parent rocks will give an idea of the anthropogenic influence on the susceptibility of the soil. This study was carried out in Kogi State, North Central Nigeria, with the aim of determining the depth of the boundary between the anthropogenic influences on soil magnetic susceptibility from those of a lithogenic origin. Magnetic susceptibility measurements were carried out on 1,760 soil samples, collected from 220 soil profiles at a depth of 80.0 cm and at intervals of 10.0 cm. From the spatial distribution of magnetic susceptibility maps at different depths, the boundary between the basement complex and the sedimentary basin was clearly demarcated. The result further shows the highest magnetic susceptibility values of 350–650 × 10−5 SI, which dominates the surface soil to a depth of 40.0 cm. At the depth of 40–50 cm, the result indicates the combination of a natural anthropogenic influence on soil magnetic susceptibility with an average of 250 × 10−5 SI. Furthermore, no evidence of layering along the depth sections was observed, suggesting that the soil profiles indicate areas mainly covered by anthropogenically influenced susceptibility, which were localized and restricted to commercial places within the state. This study reveals that the average depth of soil affected by anthropogenic pollutants is between 40–50 cm in commercial places and 20–30 cm in other places with less commercial activities.
Characteristics of the soil microbial community in the forestland ofCamellia oleifera
Authors: Zhang Peng , Cui Zhiyi , Guo Mengqing , Xi Ruchun
Published: May 2020

Characterizing soil microbial community is important for forest ecosystem management and microbial utilization. The microbial community in the soil beneathCamellia oleifera, an important woody edible oil tree in China, has not been reported before. Here, we used Illumina sequencing of 16S and ITS rRNA genes to study the species diversity of microorganisms inC. oleiferaforest land in South China. The results showed that the rhizosphere soil had higher physicochemical properties, enzyme activities and microbial biomass than did the non-rhizosphere soil. The rhizosphere soil microorganisms had a higher carbon source utilization capacity than the non-rhizosphere soil microorganisms, and attained the highest utilization capacity in summer. The soil microbial community ofC. oleiferawas characterized by rich ester and amino acid carbon sources that played major roles in the principal functional components of the community. In summer, soil microbes were abundant in species richness and very active in community function. Rhizosphere microorganisms were more diverse than non-root systems in species diversity, which was associated with soil pH, Available phosphorous (AP) and Urease (URE). These results indicated that microbial resources were rich in rhizosphere soil. A priority should be given to the rhizosphere microorganisms in the growing season in developing and utilizing soil microorganisms inC. oleiferaplantation. It is possible to promote the growth ofC. oleiferaby changing soil microbial community, including carbon source species, pH, AP, and URE. Our findings provide valuable information to guide microbial isolation and culturing to manageC. oleiferaland.
Effect of Seed Position in the Pod on the Germination and Development of Telfairia occidentalis
Authors: Ekwealor K. U. , Iroka C. F. , Okezue V. C. , Anyanele W. C. , Eze H. N.
Published: May 2020

This study was aimede effect of seed location in the pod on the germination and development of Telfairia occidentalis and to identify the portion of the seed pod that contain more female plants. This study was conducted at the Department of Botany experimental garden, Nnamdi Azikiwe University, Awka during the 2019 planting season. There was five different seed location in the pod, the far-head (FH), near-head (NH), middle (M), far-tail (FT) and near-tail (NT) regions which were treated with poultry manure. The results of this study revealed that the location of seed in the seed pod of fluted pumpkin affects germination and vegetative growth. The growth parameter data results showed that the seeds located in the middle section of a pod of fluted pumpkin are far much better than those seeds collected from the head section in terms of length of vine, stem girth, a number of nodes number of leaves, leaf area, percentage of germination, fresh weight and dry weight. The results provide an important tool for the improvement of the yield of fluted pumpkin and also a foundation for numerous researches yet to come.
Ion Exchange: The Most Important Chemical Reaction on Earth after Photosynthesis
Authors: Meetei Thounaojam Thomas , Devi Yumnam Bijilaxmi , Chanu Thounaojam Thorny
Published: May 2020

Ion exchange is the interchange of equivalent amount of ions from the solution with ions which are swarming in a boundary of charged surface in equilibrium. It is developed due to the presence of charge in the soil colloids or layer lattice clay minerals. The source of charge developed in the colloidal surface site of soil is mainly from two processes viz. isomorphous substitution and pH dependent charge. The charge can be positive or negative due to the exchange reaction in the layer lattice. The ion exchange capacity is the sum of cation exchange capacity (CEC) and anion exchange capacity (AEC). It depends on the types of soil and the amount of charge present in the layer lattice colloidal structure. With high negative charge in the lattice surface the CEC increases and with positive charge the AEC. Ions with higher charge have larger affinity to adsorbed more strongly than lower. Ion exchange capacity in soil has the ability to retained more nutrients in the form of cations or anions making available to plant for a long time which improved the fertility of soil. Leaching loss of different nutrients from the soil is reduced by holding different ions. Ion exchange processes have been widely used for heavy metal removal for waste water treatment and water purification because of its high remedial capacity, high removal efficiency and fast kinetic. Due to its applications in agriculture, environmental management, industries, waste water treatment in mining industries,  laboratory, nanotechnology, geotechnical and other soil reclamation processes it is considered as the second most important reaction in the globe after photosynthesis.
Role of Clinical Electives on Academic Career: A Cross Sectional Study
Authors: Ali Sajjad , Devi Anjuli , Humera Raja Azhar , Sohail Muhammad Taha , Saher Fizza , Qureshi Jabbar Ahmed
Published: May 2020

Introduction: Clinical Health Electives are an important part of academic curriculum in medical universities throughout the world. Electives are useful in developing personal and professional growth among students. Hence understanding the importance of electives among medical undergraduates on their academic life is important.

Materials and Methods: A cross-sectional based study was conducted among medical undergraduates in Karachi, Pakistan. A total number of 300 students from 3rd, 4th and 5th year of MBBS were taken as a sample. Consent was taken from the participants and questionnaire was filled from everyone. Study population was selected who did at least one clinical elective in their whole academic period.

Results: According to our analysed results, undergraduate students from both private and public sector medical institutes perceived clinical electives as an advantage to themselves. Majority of the students saw their clinical and academic performances to be on a higher level. This shows that opting for electives regardless of its type (local or international) have proven to be fruitful for the undergraduates’ personal growth and academic career, allowing more scope for understudies to practice and enhance their skills they have only done a limited number of times, which inevitably leads to a steep learning curve.

Conclusion: There was a positive influence of clinical electives observed among the students. Overall the academic and clinical performance of the undergraduates enhanced by opting clinical electives and has positive impact on them.
An Empirical Comparative Analysis of Airport Security Screeners' Perception of Employment Systems and Cooperation within an Airport Authority for Effective Disaster Response
Authors: So Daeseop , Park Sungsik
Published: May 2020

This study analyzed and compared airport security screeners' perception of the employment system and cooperation within a company working at both Incheon and Gimpo international airports. Based on empirical research, suggestions for changes to policy were made to improve the disaster response of an airport authority. It was proven that, if the current transition policy of aviation security screeners' employment systems were implemented as planned, the efficiency of security screening would improve and the number of aviation security breaches would significantly decrease. Additionally, it was found that surveyed employees from both airports perceived that the employment transition to establish a government-owned company must be expedited to improve aviation security for effective disaster response of an airport authority.
High-Energy Impact Behaviors of Concrete Structures Strengthened with Multi-Walled Carbon Nanotube Composites
Authors: Choi Hyung-Bae , Lee Sang-Youl
Published: May 2020

This study analyzed high-energy impact behaviors of concrete structures strengthened with multi-walled carbon nanotube (MWCNT) composites. The proposed multi-walled carbon nanotubes demonstrated excellent mechanical properties such as high stiffness, high strength, and improved elongation. These distinctive properties allow the use of the product in several high-performance applications. Using a multi-scale analysis, we investigated the impact mechanism of an MWCNT-reinforced concrete structure using various parameters. The parametric studies focused on the various impact effects on structural performance. In addition, a three-dimensional simulation was carried out for the verification of our experimental results.
Novel Theoretical Self‐Consistent Mean‐Field Approach to Describe the Conductivity of Carbon Fiber‐Filled Thermoplastics: Part III—Application of the Concept to Mechanical Properties of Composites and Polymer Solutions
Authors: Schubert Dirk W.
Published: May 2020

A novel theoretical approach, which yields a nonlinear differential equation for the mechanical properties of fiber‐filled composites as a function of the volume fraction of the filler and the fiber orientation, is shown. Furthermore, the transfer to polymer solutions is shown and gives a physical explanation for various well‐known empirical relations and numerical values including the Huggins constant and the exponent of power–law molar mass dependence of the polymer melt viscosity.
The Progress and Prospect of Zeolitic Imidazolate Frameworks in Cancer Therapy, Antibacterial Activity, and Biomineralization
Authors: Maleki Aziz , Shahbazi Mohammad‐Ali , Alinezhad Vajiheh , Santos Hélder A.
Published: May 2020

The progressive development of zeolitic imidazolate frameworks (ZIFs), as a subfamily of metal‐organic frameworks (MOFs), and their unique features, including tunable pore size, large surface area, high thermal stability, and biodegradability/biocompatibility, have made them attractive in the field of biomedicine, especially for drug delivery and biomineralization applications. The high porosity of ZIFs gives them the opportunity for encapsulating a high amount of therapeutic drugs, proteins, imaging cargos, or a combination of them to construct advanced multifunctional drug delivery systems (DDSs) with combined therapeutic and imaging capabilities. This review summarizes recent strategies on the design and fabrication of ZIF‐based nansystems and their exploration in the biomedical field. First, recent developments for the adjustment of particle size, functionality, and morphology of ZIFs are discussed, which are important for achieving optimized therapeutic/theranostic nanosystems. Second, recent trends on the application of ZIF nanocarriers for the loading of diverse cargos, including anticancer medicines, antibiotic drugs, enzymes, proteins, photosensitizers, as well as imaging and photothermal agents, are investigated in order to understand how multifunctional DDSs can be designed based on the ZIF nanoparticles to treat different diseases, such as cancer and infection. Finally, prospects on the future research direction and applications of ZIF‐based nanomedicines are discussed.
Can Reconstructed Se‐Deficient Line Defects in Monolayer VSe2 Induce Magnetism?
Authors: Chua Rebekah , Yang Jing , He Xiaoyue , Yu Xiaojiang , Yu Wei , Bussolotti Fabio , Wong Ping Kwan Johnny , Loh Kian Ping , Breese Mark B. H. , Goh Kuan Eng Johnson , Huang Yu Li , Wee Andrew T. S.
Published: May 2020

There have been several recent conflicting reports on the ferromagnetism of clean monolayer VSe2. Herein, the controllable formation of 1D defect line patterns in vanadium diselenide (VSe2) monolayers initiated by thermal annealing is presented. Using scanning tunneling microscopy and q‐plus atomic force microscopy techniques, the 1D line features are determined to be 8‐member‐ring arrays, formed via a Se deficient reconstruction process. The reconstructed VSe2 monolayer with Se‐deficient line defects displays room‐temperature ferromagnetism under X‐ray magnetic circular dichroism and magnetic force microscopy, consistent with the density functional theory calculations. This study possibly resolves the controversy on whether ferromagnetism is intrinsic in monolayer VSe2, and highlights the importance of controlling and understanding the atomic structures of surface defects in 2D crystals, which could play key roles in the material properties and hence potential device applications.
Anode‐Free Full Cells: A Pathway to High‐Energy Density Lithium‐Metal Batteries
Authors: Nanda Sanjay , Gupta Abhay , Manthiram Arumugam
Published: May 2020

The development of high‐energy density batteries is critical to the decarbonization of the transportation and power generation sectors. For any given lithium‐containing cathode system, the anode‐free full cell configuration, which eliminates excess lithium and pairs the fully lithiated cathode with a bare current collector, can deliver the maximum possible energy density. The absence of free lithium metal during cell assembly confers significant practical advantages as well. It is also the ideal framework for developing a thorough understanding of lithium deposition in conjunction with various cathode systems. However, the poor efficiencies of lithium plating and stripping lead to rapid lithium inventory loss and poor cycle life. In the last few years, multiple studies have demonstrated the application of advanced electrolytes, modified current collectors, and optimized formation and cycling parameters to stabilize lithium deposition and improve cycle life (80% capacity retention) to 100 cycles and beyond. This review provides an overview of the various strategies toward sustaining lithium inventory in anode‐free full cells and summarizes the work undertaken in this nascent field. It is expected that further improvement upon these strategies and a combinatorial approach can enable cycle lives far in excess of what has been achieved so far.
A pore network model for calculating pressure drop in packed beds of arbitrary‐shaped particles
Authors: Liu Xinlei , Peng Chong , Bai Hongxin , Zhang Qunfeng , Ye Guanghua , Zhou Xinggui , Yuan Weikang
Published: May 2020

A pore network model is built to predict pressure drop in packed beds of arbitrary‐shaped particles, using a method that consists of particle packing by the rigid body technique, pore network construction by the maximal sphere algorithm, and numerical calculation of fluid flow. The pore network model is firstly validated by comparing with experiments, Ergun‐type equations, and particle‐resolved computational fluid dynamics (CFD). The pore network model is as accurate as the particle‐resolved CFD, and is remarkably two to three orders of magnitude less computationally intensive. Then, the pore network model is used to calculate the pressure drops in the beds packed with particles of different shapes and sizes, as well as using different flow media. These calculation results prove the versatility of the pore network model. This work provides an accurate yet efficient pore network model for predicting pressure drop, which should be a powerful tool for designing packed beds.
Metal‐Free N‐Annulation of 3‐Formylchromones with α‐Amino Ketones for the Construction of Diverse N‐Functionalized Pyrroles
Authors: Shrestha Rajeev , Khanal Hari Datta , Yang Won‐Guen , Kim Sung Hong , Shim Jae‐Jin , Lee Yong Rok
Published: May 2020

A novel and efficient one‐pot approach for the synthesis of diverse and polyfunctionalized pyrroles by the mild organic base‐promoted N‐annulation of 3‐formylchromones with N‐(2‐oxo‐2‐arylethyl)sulfonamides, N‐(2‐oxo‐2‐phenylethyl)methanesulfonamide, or 1‐phenyl‐2‐(phenylamino)ethan‐1‐ones is described. The reaction proceeds via cascade Knoevenagel condensation/intramolecular Michael addition/ring opening. This protocol provides rapid access to biologically interesting polysubstituted pyrroles bearing N‐arylsulfonyl/N‐methylsulfonyl/N‐aryl moieties or a free N−H group.
Effects of Thermally Induced Roton‐Like Excitation on the Superfluid Density of a Quasi‐2D Dipolar Bose Condensed Gas
Authors: Yavari Heshmatollah , Forouharmanesh Forouzan
Published: May 2020

Using the Green's function approach, the density–density correlation function and the dielectric function in the random‐phase approximation for a quasi‐two‐dimensional (quasi‐2D) dipolar Bose gas are derived. From the pole of the density correlation function, by considering thermally induced roton‐like excitations, the excitation spectrum of the system is calculated. It is shown that the position and depth of the roton minimum of the excitation spectrum are tunable by changing the temperature. To show how the position of the roton minimum influences the phenomenon of superfluidity, the superfluid density of the system is obtained and it is shown that the interplay of the thermal rotonization, contact and dipole–dipole interaction (DDI) can affect the superfluid fraction of a quasi‐2D Bose gas. It is found that contact, DDI interactions, and thermally induced rotons enhance the fluctuations and reduce the superfluid density. In the absence of DDI and thermally induced rotons, the usual T3 dependence of superfluid density in 2D is obtained and the correction T4 term arises from DDI. It is shown that if the roton minimum is close to zero, the thermally induced rotons change the linear temperature dependence of the superfluid fraction, leading to a transition to nontrivial supersolid phase.
Reversible Circular Dichroism Induced by Energy Losses without Changing Chirality of Structure
Authors: Deng Junchen , Wang Tiankun , Ng Sha Shiong , Liu Guangqiao
Published: May 2020

Tunable circular dichroism (CD) is widely used in biology signal detection and chemical analysis. Researchers usually tune CD by changing the chirality and symmetry of nanostructures either directly or indirectly. Changes to a planar nanostructure's chirality are resisted by its structural reciprocity, which also constrains its CD tuning. However, the distribution of finite non‐radiative (ohmic) losses on a planar nanostructure will not be constrained by the reciprocity of structure. Here, a nanostructure is designed to tune the intensity of energy losses rather than change the chirality and symmetry of the whole structure. The results show that not only are the position and intensity of CD affected, but also the sign of the CD signal changes. These methods and results can help in utilizing the new approach to tune the modes and sign of a CD signal.
Huisgen's 1,3‐Dipolar Cycloadditions to Fulvenes Proceed via Ambimodal [6+4]/[4+2] Transition States
Authors: Liu Fang , Chen Yu , Houk K. N.
Published: May 2020

Huisgen's 1960 announcement of the concept of 1,3‐dipolar cycloadditions was published the year before Alder's study of the reaction of diazomethane and dimethylfulvene. The diazomethane reaction was studied again in 1970 by Houk et al. and shown to give a [6+4] adduct. Padwa's nitrile ylide cycloaddition to dimethylfulvene (1978) gave [6+4] and [4+2] adducts. We performed computational studies of these reactions with density functional theory (DFT) and show that they involve ambimodal [6+4]/[4+2] transition states that can lead to either type of cycloadduct from one transition state. We dedicate this paper to the extraordinary life and humanity of Rolf Huisgen, and to the undying influence of his discoveries on chemistry.
A novel DOPO‐containing HTBN endowing waterborne polyurethane with excellent flame retardance and mechanical properties
Authors: Wang Hui , Wang Shuang , Du Xiaosheng , Du Zongliang , Wang Haibo , Cheng Xu
Published: May 2020

A novel flame‐retardant DHTBN (hydroxyl‐terminated polybutadiene acrylonitrile modified with DOPO) with phosphorus‐containing pendant groups is synthesized based on addition reaction between the hydroxyl‐terminated polybutadiene acrylonitrile and DOPO, which is followed to prepare flame‐retarded WPU (FR‐WPU). The chemical structures of DHTBN and FR‐WPU are confirmed via 31P NMR, XPS, and FT‐IR. The mechanical properties, thermal stability, and flame retardancy of FR‐WPU are conducted a series of tests. The tensile strength and elongation at break for the FR‐WPU films first increased and then decreased with increasing of DOPO contents. The results show that the incorporation of DHTBN into the WPU backbone slightly reduces the thermal stability of FR‐WPU. However, the incorporation of DHTBN into WPU improves the flame retardancy. The TGA‐FIR and Py‐GC‐MS results indicate the gas phase flame‐retardant effect of DHTBN. Furthermore, the morphology, elemental composition, and content of residual char from the FR‐WPU exhibited condensed‐phase flame‐retardant effects on the WPU films.
Management effectiveness in marine protected areas for conservation of Antillean manatees on the eastern coast of the Yucatan Peninsula, Mexico
Authors: Robles Herrejón Juan Carlos , Morales‐Vela Benjamín , Ortega‐Argueta Alejandro , Pozo Carmen , Olivera‐Gómez León David
Published: May 2020

This study evaluated management effectiveness in three marine protected areas (MPAs) for conservation of the Antillean manatee (Trichechus manatus manatus Linnaeus 1758), located on the eastern coast of the Yucatan Peninsula, Mexico. The MPAs evaluated were the Yum‐Balam Flora and Fauna Reserve, Sian Ka'an Biosphere Reserve, and Chetumal Bay Manatee Sanctuary. The extent of the traditional, popular, and scientific manatee knowledge and research were assessed, as well as the prescribed conservation management actions, relevant stakeholders, and the degree of inclusion of manatee species in the management schemes of these MPAs.

Four general criteria, 12 specific criteria, and 62 indicators were developed. In total, 199 interviews were completed in seven communities of the MPAs in order to determine the perception of the social, economic, and conservation impacts of the manatee and its management.

Although the evaluated MPAs were not wholly comparable among themselves due to their different management categories and schemes, administration, socio‐economic context, and the dynamics and conflicts encountered, a comparison was conducted using standardized criteria and a categorical scale in order to evaluate the level of effectiveness of each MPA.

The MPA with the highest management effectiveness in manatee conservation was found to be the Chetumal Bay, with an effectiveness classed as good (71%), followed by Sian Ka'an with intermediate effectiveness (53%) and Yum‐Balam, also with intermediate effectiveness (43%).

The relationships between the key stakeholders of the three MPAs and economic activities such as fishing and tourism are the factors that most influence the effectiveness of management for manatee conservation.