bluuebunny/crossref_metadata_2025 huggingface dataset:
[C ii] and CO Emission along the Bar and Counter-arms of NGC 7479*
Authors: Fadda Dario , Laine Seppo , Appleton Philip N.
Published: March 2021

We present new SOFIA [C ii] and ALMA CO
J=1→0 observations of the nearby asymmetric barred spiral galaxy NGC 7479. The data, which cover the whole bar of the galaxy and the counter-arms visible in the radio continuum, are analyzed in conjunction with a wealth of existing visible, infrared, radio, and X-ray data. As in most normal galaxies, the [C ii] emission is generally consistent with emission from cooling gas excited by photoelectric heating in photodissociation regions. However, anomalously high [C ii]/CO ratios are seen at the two ends of the counter-arms. Both ends show shell-like structures, possibly bubbles, in Hα emission. In addition, the southern end has [C ii]-to-infrared emission ratios inconsistent with normal star formation. Because there is little H i emission at this location, the [C ii] emission probably originates in warm shocked molecular gas heated by the interaction of the radio jet forming the counter-arms with the interstellar medium in the galaxy. At two other locations, the high [C ii]/CO ratios provide evidence for the existence of patches of CO-dark molecular gas. The [C ii] and CO observations also reveal resolved velocity components along the bar. In particular, the CO emission can be separated into two components associated with gas along the leading edge of the bar and gas trailing the bar. The trailing gas component that amounts to approximately 40% of the gas around the bar region may be related to a minor merger.
Dust Growth in Molecular Cloud Envelopes: A Numerical Approach
Authors: Beitia-Antero Leire , Gómez de Castro Ana I.
Published: March 2021

Variations in the grain size distribution are to be expected in the interstellar medium (ISM) owing to grain growth and destruction. In this work, we present a dust collision model to be implemented inside a magnetohydrodynamic (MHD) code that takes into account grain growth and shattering of charged dust grains of a given composition (silicate or graphite). We integrate this model in the MHD code Athena and build on a previous implementation of the dynamics of charged dust grains in the same code. To demonstrate the performance of this coagulation model, we study the variations in the grain size distribution of a single-sized population of dust with radius 0.05 μm inside several dust filaments formed during a 2D MHD simulation. We also consider a realistic dust distribution with sizes ranging from 50 Å to 0.25 μm and analyze the variations in both the size distribution for graphite and silicates and the far-ultraviolet extinction curve. From the obtained results, we conclude that the methodology here presented, based on the MHD evolution of the equation of motion for a charged particle, is optimal for studying the coagulation of charged dust grains in a diffuse regime such as a molecular cloud envelope. Observationally, these variations in the dust size distribution are translated into variations in the far-ultraviolet extinction curve, and they are mainly caused by small graphite dust grains.
Presolar Silicate and Oxide Grains Found in Lithic Clasts from Isheyevo and the Fine-grained Matrix of Northwest Africa 801
Authors: Sanghani Manish N. , Marhas Kuljeet Kaur , Hsiao Silver Sung-Yun , Peeters Zan , Shang Hsien , Lee Der-Chuen , Bizzarro Martin
Published: March 2021

We report on the discovery of 33 oxygen-anomalous grains from the CH3/CBb3 chondrite Isheyevo and the CR2 chondrite Northwest Africa (NWA) 801. Oxygen isotopic compositions indicate the origin of the majority grains in stellar outflows of low-mass (∼1.2 to ∼2.2 M
⊙), solar-metallicity red giant or asymptotic giant branch stars, while highly 17O-enriched grains probably have nova origins. Isotopic compositions of the eight 18O-rich grains, including an extremely 18O-rich grain (∼16 times solar 18O/16O ratio), are reproduced by zone mixing of SNe II ejecta. Close-to-normal silicon, magnesium, and calcium isotopic compositions of grains are consistent with the isotope exchange in the interstellar medium or the meteorite parent body, while two grains with Si isotopic anomalies and one grain with Mg isotopic anomalies reflect the Galactic chemical evolution. An Isheyevo clast showed several hot spots with moderate to high 15N enrichments, including a hot spot with an extreme 15N excess of (7225 ± 316)‰. However, no correlation between 15N enrichment and presolar oxygen-rich grain abundance is found. Grains with elliptical shapes probably indicate primary condensation feature. Two complex grains possibly display decoupling of the isotopic and elemental compositions in the grain formation environments. The low silicate-to-oxide abundance ratio for the fine-grained chondrule rims in NWA 801 likely reflects the preferential destruction of silicates due to terrestrial weathering. In NWA 801, the presolar O-rich grain abundance in fine-grained chondrule rims is higher than in the interchondrule matrix, similar to the trend observed for some aqueously altered chondrites of petrologic type 2.
Spectroscopy of the 2015 Outburst of AG Pegasi
Authors: Mistry Dharmesh , Steele Iain A.
Published: March 2021

Between 2015 September and 2016 January, we obtained 18 spectra of the 2015 classical outburst of AG Pegasi—a symbiotic star consisting of a white dwarf (WD), red giant, and surrounding nebula. Modelling the flux contributions of these components reveals that nebular emission, from the reprocessing of high energy WD photons, dominates the 3200–6300 Å range. Nebular emission rises and falls in line with changes seen in the WD, whose properties have been derived using Hβ and He ii (4686 A) line flux, and emission measure calculations. WD parameters follow changes seen in visual band light curves. During the second peak of the outburst, WD temperatures reach 166,000 ± 6000 K, with a luminosity and radius of 14,000 ± 2000 L
⊙ and 0.149 ± 0.014 R
⊙ respectively. These features are consistent with an expansion of the WD pseudo-photosphere due to an accretion rate exceeding that required for stable hydrogen burning.
Biofertlizer Lumbrical improves the growth and ex vitro acclimatization of micropropagated pear plants
Authors: Dimitrova Nataliya , Nacheva Lilyana , Berova Małgorzata , Kulpa Danuta
Published: March 2021

In vitro micropropagation of plants is highly useful for obtaining large quantities of planting material with valuable economic qualities. However, plantlets grow in vitro in a specific environment and the adaptation after the transfer to ex vitro conditions is difficult. Therefore, the acclimatization is a key step, which mostly determines the success of micropropagation. The aim of this investigation was to study the effect of the biofertlizer Lumbrical on ex vitro acclimatization of micropropagated pear rootstock OHF 333 (Pyrus communis L.). Micropropagated and rooted plantlets were potted in peat and perlite (2:1) mixture with or without Lumbrical. They were grown in a growth chamber at a temperature of 22±2 °C and photoperiod of 16/8 hours supplied by cool-white fluorescent lamps (150 µmol m-2 s-1 Photosynthetic Photon Flux Density, PPFD). The plants were covered with transparent foil to maintain the high humidity, and ten days later, the humidity was gradually decreased. Biometric parameters, anatomic-morphological analyses, net photosynthetic rate and chlorophyll a fluorescence (JIP test) were measured 21 days after transplanting the plants to ex vitro conditions. The obtained results showed that the plants, acclimatized ex vitro in the substrate with Lumbrical, presented better growth (stem length, number of leaves, leaf area and fresh mass) and photosynthetic characteristics as compared to the control plants. This biostimulator could also be used to improve acclimatization in other woody species
Comparison of tree diameter distributions in managed and unmanaged Kazdağı fir forests
Authors: Kara Ferhat
Published: March 2021

Forest structural complexity affects tree growth, species diversity, understory seedling density, wildlife habitat and fire behaviour. Thus, defining the structural complexity of forest ecosystems would play a crucial role in their management. The vertical structure in stands of shade-tolerant tree species can be described by using the distribution of tree diameters. In this study, the main objective was to determine and compare the diameter distribution patterns of managed and unmanaged Kazdağı fir (Abies nordmanniana subsp. equi-trojani) forests in northern Turkey. Hierarchical clustering analysis was used to define the diameter distribution patterns. Three main diameter distribution patterns were examined in both managed and unmanaged forests. Two of the patterns in the managed forest did not possess the expected diameter structure of selection silviculture (i.e. reverse J-shape). The observed patterns in the unmanaged forest were mostly representative of the diameter structure of old-growth forests. Given the initial findings, it is likely that the small-scale disturbances created by selection methods may not be adequate to establish and recruit sufficient number of trees into small- diameter sizes in Kazdağı fir forests. The assessment of patterns of tree diameter distribution in these forests would create a basis for future research, aiming to enhance the structural complexity.
Towards Understanding the Students’ Acceptance of MOOCs: A Unified Theory of Acceptance and Use of Technology (UTAUT)
Authors: Muti Altalhi Maryam
Published: March 2021

Massive Open student’s courses (MOOC) have stimulated the efforts made for improving the learning techniques and enhancing it the spectrum for students learning. Unfortunately, the acceptance of MOOC as a learning instrument re-mained low, which is perceived as an entertainment tool rather than an academic tool, particularly in developing countries. The study evaluated the student’s adap-tation of MOOC as an academic tool. It developed an understanding of the asso-ciated factors which impact the students’ decision towards utilizing MOOC as a learning instrument. It initially investigated the constructs of the native UTAUT, subsequent to which is derived theory from the literature, amplifying the UTAUT theory scope by instigating e-learning factors associated with MOOC, such as at-titude and self-efficacy. Based on the established framework, a survey was con-ducted where 150 MOOCs’ students were recruited. The collected data were sta-tistically analyzed using SPSS. The results showed that acceptance of the MOOCs was substantially affected by its performance expectancy, effort expec-tancy, social influence, self-efficiency, attitude, and facilitating conditions. It also suggested that efforts should be introduced to promote the use of MOOCs among the academic institutes in Saudi Arabia.
An Analysis of Thai Student Teacher Appropriate Internet Use Behaviour
Authors: Leekitchwatana Punnee , Pimdee Paitoon
Published: March 2021

The goals of this research were to analyse and develop a Hierarchical Linear Model (HLM) of appropriate Internet use behaviour of Thai student teachers. The sample group consisted of 1,800 student teachers studying for their bachelor’s degree at 30 Thai government educational institutions. The research tool used was a questionnaire with content validity and reliability at 0.83 – 0.92. Mean (¯(x )), standard deviation (S.D.), and HLM were used to analyse the data. The findings revealed that appropriate Internet use behaviour in Thai student teachers was at a high level. Additionally, the HLM for appropriate Internet use behaviour for Thai student teachers consisted of two levels of predictor variables. The first level was the student teacher level, in which six of the hypothesized nine predictor variables had statistical significance. Five had a positive effect, which included ability, affect, family situation, gender, and GPA, while one variable had a negative effect, which was income. The second level was the institutional level, which contained two predictor variables with statistical significance, friends and educational institution situation, with both having positive effects. Friends had a direct effect on behaviour at the educational institution level, while educational institution situation had an effect through ability.
Flipped Classroom in Programming Course: A Systematic Literature Review
Authors: Hendrik Hendrik , Hamzah Almed
Published: March 2021

The emerging trend technologies imply the increase in the new role of the future of jobs. Most of them required Computer Science-related skills a lot, especially programming. However, there is a skill gap for it. Some previous studies showed that many students feel difficulties in learning programming. In the last decades, there are many approaches to improve student’s learning achievement through active learning methods. One of those approaches is the Flipped Classroom (FC) method. This study presents a systematic literature review of the FC approach in the programming course. The aim of this study is to explore the strategy of FC implementation in the programming class. A total of 32 papers from ACM Digital Library and IEEE Xplore Digital Library are selected for this review. We found four types of implementation of FC in programming, with the variations of the in-class or out-class activities.
University Support, Teaching Competencies and Entrepreneurial Competencies in Software Engineering and Graphic Design Students
Authors: Madrid Moreno Oswaldo Alberto , Nuñez Ramírez Marco Alberto
Published: March 2021

The objective of this research was to evaluate how university support and teaching entrepreneurial competencies affect students' entrepreneurial com-petencies. As an empirical test, a sample of 201 software engineering and graphic design students from a university in Northwest Mexico was taken, where it was possible to corroborate three hypotheses. The results suggest that entrepreneurial competencies are influenced by external aspects, where the university can be understood as an open system, but also, as a part of a wider system within the triple helix. This shows that the joint work between the contextual and individual part can benefit the generation of innovation and development for society, especially in a country where there is a lack of R&D, although the practice of entrepreneurship is high. As a result, the uni-versity can play a relevant role when developing entrepreneurial competen-cies to train students to become entrepreneurs through innovation and tech-nology.
Research on Innovative Teaching Mode of Art Education in the Age of Convergence of Media
Authors: Ma Zhiyuan , Guan Jingjing , Li Rita Yi Man
Published: March 2021

ssemination and development of information has occurred, and this has had a positive impact on audiences. Research on the integration and develop-ment of traditional media with new media is recent, and has been focused, across the world, on the educational context. This study most specifically looks at art education. Or art teachers in further and higher education, the use of electronic media may not only lead to better work, creatively, but al-so more efficient real-time interaction, and the more effective collection of student feedback. Modern students’ lifestyles and the teaching environment they are subject to, have created the basis for convergence media; within such an environment, cultural knowledge can be more quickly and conven-iently accessed. Based on an analysis of innovative art education teaching methods within this era of convergent media, this paper proposes a design framework for the sharing of such high-quality teaching resources and the design of a shared teaching platform; these proposals are informed by the use of the ‘extreme value’ method to optimize the allocation of high-quality teaching resources in the framework design during the sharing process. The identification of an objective function can be effective in this context. The participation of an objective function within resource allocation can better guarantee that the best teachers can arrange the teaching programs that are most effective for particular courses --- so that high-quality teaching pro-grams can be better spread across the media available and so that the stu-dents can better accept and absorb this new teaching mode.
A Multi-Attribute Fuzzy Evaluation Model for the Teaching Quality of Physical Education in Colleges and Its Implementation Strategies
Authors: Wang Yao , Sun Chunyan , Guo Ying
Published: March 2021

There are two major problems with teaching quality evaluation of physical education (PE) in colleges: the excessive number of evaluation factors, and the incomplete evaluation system. To solve the problems, this paper puts forward a multi-attribute fuzzy evaluation model of college PE teaching quality, and provides the strategies to implement the model. Firstly, the problems of college PE teaching were analyzed, and a novel multi-dimensional evaluation system was developed for college PE teaching quality. To quantify college PE teaching quality, an evaluation model of college PE teaching quality was established based on the Grey Relational Analysis (GRA). In addition, several strategies were presented to improve college PE teaching quality. The proposed model and strategies provide a good reference for solving similar complex system problems.
An Evaluation Model for the Innovation and Entrepreneurship Thinking Ability of College Students Based on Neural Network
Authors: Zhang Feng , Xi Limin
Published: March 2021

Mass innovation and entrepreneurship (I&E) is a national campaign in China. In this context, it is important to encourage college students to engage in I&E activities, and this calls for accurate and comprehensive evaluation of their I&E thinking ability. Therefore, this paper proposes an evaluation model for the I&E thinking ability of college students based on neural network (NN). Firstly, a reasonable evaluation index system was created for the I&E thinking ability of college students, and the evaluation indices were preprocessed through fuzzy analytic hierarchy process (AHP). Then, a fuzzy neural network (FNN) was constructed based on GA rule optimization and the specific steps of the algorithm were given. Moreover, a few representative rules were selected by GA based on uncertain fuzzy knowledge rules, a 4-layer NN model with fuzzy inputs and outputs was established, and the evaluation flow of the I&E thinking ability of college students was proposed. Finally, the effectiveness of the proposed model was verified through experiments. The research results of this paper provide a reference for the application of NN in the field of ability evaluation.
Codependency, Psychological Problems and Time of Exposure to Parents with a History of Psychoactive Substance Dependence: Appointments
Authors: Costa Cintia Maria Rosa Faria da , Oliveira-Monteiro Nancy Ramacciotti de
Published: March 2021

O conceito de codependência é controverso, reportando-se a dificuldades psicológicas de familiares de dependentes de substâncias psicoativas, bem como abrangendo contextos de desestruturação familiar não associados à dependência dessas substâncias. A pesquisa teve por objetivo avaliar codependência e problemas internalizantes e externalizantes em adolescentes, filhos de pais com histórico de dependência a substância psicoativa, segundo sexo, e possível correlação entre codependência e tempo de exposição a esse membro da família, também segundo sexo. O estudo avaliou 30 adolescentes, de 13 a 18 anos, em um município do Estado de São Paulo, Brasil. Com o uso da Escala Spann-Fischer de Codependência e do Youth Self Report, foi verificada forte correlação entre a codependência e problemas psicológicos nas meninas. Ademais, foi encontrada forte correlação positive entre codependência e exposição intermitente ao familiar dependente de substâncias psicoativas, para meninos da amostra. Para meninos e meninas, não houve correlação entre codependência e exposição contínua ao familiar dependente, o que sugere que a codependência transcende a mera presença da pessoa com histórico de dependência de substâncias psicoativas.
Reconquistando o coração democrático da educação
Authors: Biesta Gert
Published: March 2021

No presente ensaio, o filósofo Gert Biesta aprofunda-se na análise das relações entre educação, aprendizagem e democracia. Sua abordagem teórica tem contribuído significativamente para as teorizações pedagógicas contemporâneas, tanto no Brasil, quanto no cenário internacional.
Reconceptualizando as práticas pedagógicas numa visão pós-humana: um caso em estudo
Authors: Silva Patrícia , Feitoza Rayan De Brito
Published: March 2021

Nosso ponto de partida inicia-se com o Pós-Humano e a relação humanos e não-humanos nas práticas pedagógicas. Porque entendemos que é essencial perceber que todas as práticas emergem de enredos entre pessoas e objetos/coisas. Analisamos as aulas de uma disciplina, em ambiente virtual. Metodologicamente, dialogamos com a Etnografia das Redes Sociotécnicas como alternativa a partir da pesquisa pós-qualitativa. Práticas pedagógicas numa visão pós-humana, são atividades com as quais os agentes humanos e não-humanos atuam em conjunto, interagindo e formando alianças e vínculos. Analisar práticas pedagógicas é fundamental para se entender o protagonismo humano-não-humano, nos mostrando redes de interações sociotécnicas, com o objetivo de (des)individualizar e superar o humano em tais práticas.
An Affordable, Virtual Reality Based Training Application for Cardiopulmonary Resuscitation
Authors: Kegalle H. N. , Liyanage H. S. U. , Jayaratne K. L. , Wickramasinghe M. I. E.
Published: March 2021

In Medical science, proficiency in Cardiopulmonary Resuscitation (CPR) is considered as a vital skill for physicians. For training CPR, medical professionals use mechanical manikin which has some drawbacks when it comes to the realism of the simulation and the feedback of performance. This paper presents a Virtual Reality (VR) based solution to address some of these shortcomings. The approach here is augmenting the mechanical manikin with VR using HTC Vive, Leap Motion Controller, and a glove. To test the acceptance of this solution, a user-based evaluation was carried out. 85.7% of the users who have participated in the evaluation have expressed their preference upon using VR in CPR training. Even though the overall evaluation depicts a neutral output, this study opens avenues for future research in combining VR into medical training processes.
The association between activity levels and skin moisturising function in adults
Authors: Oizumi Ryosuke , Sugimoto Yoshie , Aibara Hiromi
Published: March 2021

Factors associated with skin moisture retention include age and lifestyle, such as diet and sleep efficiency. However, the impact of exercise habits on skin moisturising function is unclear. We surveyed 86 participants from a Japanese university about their activity levels using the International Physical Activity Questionnaire. We also examined their skin moisturising function, measuring stratum corneum (SC) hydration levels and transepidermal water loss (TEWL). Comparisons of participants’ activity levels, SC hydration, and TEWL, accounting for their gender and age differences, revealed activity levels significantly related to differences in SC hydration levels. Results of multiple comparisons showed increased activity relates to significantly higher SC hydration − the higher the activity levels, the higher the hydration. No difference was found in TEWL. The results suggest exercise habits can prevent dry skin. The findings may be useful for the prevention and treatment of dry skin and promoting the benefits of exercise.
Transformation of a myelodysplastic syndrome to acute myeloid leukemia and concurrent necrotizing sweet syndrome
Authors: Vera-Lastra Olga , Olvera-Acevedo Arturo , Pulido-Díaz Nancy , Quintal-Ramírez Marissa de Jesús , Ordoñez-González Irvin , Cimé-Aké Erik , Cruz-Domínguez María Pilar , Medina Gabriela
Published: March 2021

The Sweet’s syndrome, is an inflammatory skin disorder characterized by extensive infiltration of neutrophils in the dermis with extension to the subcutis, known as acute febrile neutrophilic dermatosis. It may occur as a paraneoplastic syndrome. To our knowledge, there are currently few reports about transformation of a myelodysplastic syndrome to acute myeloid leukemia and concurrent necrotizing Sweet syndrome in the literature. Herein we describe an unusual case in a young patient with these characteristics that evolved to a fatal outcome.
Diffuse cutaneous mastocytosis masquerading as linear IgA bullous dermatosis of childhood
Authors: Rayinda Tuntas , Oktarina Dyah Ayu Mira , Danarti Retno
Published: March 2021

Diffuse cutaneous mastocytosis is a rare form of cutaneous mastocytosis that can appear in heterogeneous clinical presentations, including eruption of papules, erythematous plaques, blisters, and erythroderma. We report a 1.5- year-old boy who presented with itchy wheals and blisters spreading on his body. The patient was initially managed as a linear IgA bullous dermatosis of childhood because of the similarity of clinical symptoms and the presenting of linear IgA deposits at the basement membrane. Due to the development of urticarial plaque after the resolution of the blisters, the diagnosis of diffuse cutaneous mastocytosis was made based on clinical, histopathological (hematoxylin-eosin, Giemsa, and toluidine blue staining), and direct immunofluorescent examinations (IgA, IgG, IgM, C3). The symptoms were improved following antihistamines and oral corticosteroid treatment.
Clinical heterogeneity of a population of patients admitted to the Emergency Department with a diagnosis of COPD-exacerbation: Relevance of cardiovascular comorbidities
Authors: Groff Paolo , Petrelli Giuseppina , Giorgini Paolo , Pilotti Roberto , Parato Vito Maurizio , Fabbri Andrea
Published: March 2021

FEV1-based Chronic Obstructive Pulmonary Disease (COPD) severity does not account for the complexity of the disease. Recent studies point to the high frequency of comorbidities responsible for unfavorable outcomes. There is a lack of data on this concerning the patient evaluated in the emergency setting. Aim of the study was to prospectively evaluate patients admitted to the ED for “exacerbated COPD” to describe their clinical heterogeneity and the influence that it may have on outcomes: death, length of hospitalization, exacerbation recurrence. The following data were recorded: history, symptoms, blood gas analysis, laboratory and radiological findings and comorbidities. Each patient underwent electrocardiography, echocardiography and spirometry. In order to identify a correlation between these variables and the selected outcomes, a multivariate linear logistic regression analysis was carried out. This study was conducted on 41 eligible patients consecutively admitted to the emergency room for exacerbated COPD. A consistent proportion showed ECG, Echocardiographic and laboratory abnormalities. At spirometry a FEV1 <30% of predicted was detected in 37% of patients. Cardiovascular comorbidities came out to be very frequent (hypertension, heart failure and coronary artery disease in particular). The history of heart failure was related to the risk of re-hospitalization within three months, while pneumonia, a low pH and a low FEV1 predicted a hospital stay >7 days. Our study shows that the term “exacerbated COPD” underscores a heterogeneous population, with a high prevalence of cardiovascular comorbidities, which significantly influence outcomes. Multicenter studies are needed to better investigate the clinical relevance of these findings.
Effects of degree of oil palm frond mulching using tractor mounted mulcher blades
Authors: Gambo Jahun Bala , Bin Ahmad Desa , Razif Mahadi Muhammad , Sulaiman Shamsuddin , Iya Shehu Adamu
Published: March 2021

This study investigates the influence of blade lifting angles, tractor forward speed, and tractor power take off (PTO) speed on the degree of mulching. Four blades with different lifting angles, two tractor PTO speeds, and three tractor forward speeds were assessed using the parametric test at the Universiti Putra Malaysia oil palm plantation. The result shows that the best-fit regression equation was a quadratic regression with a high coefficient of determination. It indicates that any change in this three-factor interaction has a significant effect using Tukey’s Studentized mean comparison and can predict the degree of mulching. Seventy-four percent of the degree of mulching variance is explained by blade lifting angles, tractor forward speed, and tractor PTO speed. Since the blade lifting angle was a major predictor of the degree of mulching, this result implies that any change in the blade lifting angle can provide a significant prediction of the degree of mulching in an oil palm plantation. Additionally, the predicted model can further be used to predict the degree of mulching during field operations, replanting, and access for mulching of oil palm fronds. A detailed field evaluation of the performance of a tractor-mounted mulcher with different blade lifting angles in other parts of Malaysia is highly recommended to cater for the differences in soil moisture content and bulk density.
Computational fluid dynamic simulation of a pulse-width modulated spray nozzle
Authors: Chapman Zachary , Doom Jeffrey
Published: March 2021

Computational fluid dynamics (CFD) is a useful tool used by engineers in many industries to study fluid flow. A relatively new industry to adopt the use of CFD is the agricultural industry. A spray nozzle commonly used in agricultural spraying, the Teejet 110-degree nozzle (TeeJet Technologies, 2020), was simulated. A method was developed to pulse the spray. A user-defined function was used to define the velocity at the inlet of the nozzle to pulse the spray. The domain was then extended to allow the examination of a slice 20 inches below the nozzle. The simulation results were compared to experimental results collected from a sprayer testbed. The effect of frequency was then investigated by changing the frequency of the pulses. Results from these studies show that a userdefined function can be used to pulse the spray. CFD can be used to model spray nozzles, but the validity of the results are strongly related to the computational resources available, and increasing the frequency of the pulses results in a higher concentrated spray toward the center of the spray plume. The simulations were carried out using a commercial code (CD-Adapco, 2019).
UAV-SfM 4D mapping of landslides activated in a steep terraced agricultural area
Authors: Mauri Luca , Straffelini Eugenio , Cucchiaro Sara , Tarolli Paolo
Published: March 2021

The presence of roads is closely linked with the activation of land degradative phenomena such as landslides. Factors such as ineffective road management and design, local rainfall regimes, and specific geomorphological elements actively influence landslide occurrence. In this context, recent developments in digital photogrammetry (e.g., Structure from Motion; SfM) paired with Uncrewed Aerial Vehicles (UAV) systems increase our possibilities to realize low-cost and recurrent topographic surveys. This can lead to the development of multi-temporal (hereafter: 4D) and high-resolution Digital Elevation Models (DEMs), which are fundamental to analyse geomorphological features and quantify processes at the fine spatial and temporal resolutions at which they occur. This research proposes a multi-temporal comparison of the main geomorphometric indicators describing a landslide-prone terraced vineyard to assess the observed high-steep slope failures. The possibility to investigate the evolution of landslide geomorphic features in steep agricultural systems through a high-resolution and 4D comparison of such indicators is still a challenge to be explored. In this article, we considered a case study located in the central Italian Alps, where two landslides were activated below a rural road within a terraced agricultural system. The dynamics of the landslides were monitored by comparing repeated DEMs (DEM of difference), which reported erosion values of above 20 m3 and 10 m3 for the two landslide zones and deposition values of more than 15 m3 and 9 m3, respectively. The road network’s role in the alteration of superficial water flows was proved by the elaboration of the relative path impact index. Altered water flows were expressed by values between 2σ and 4σ close to the collapsed surfaces. The increase in profile curvature and roughness index described the landslides evolution over time. Finally, the multi-temporal comparison of feature extraction underlined the geomorphological changes affecting the study area. The accuracy of features extraction was analysed through the quality index computation, expressed in a range between 0 (low accuracy) and 1 (high accuracy), and proved to be equal to 0.22 m (L1-pre), 0.63 m (L1-post), and 0.69 m (L2). Results confirmed the usefulness of high-resolution and 4D UAV-based SfM surveys to investigate landslides triggering due to the presence of roads at hillslope scale in agricultural systems. This work could be a useful starting point for further studies of landslide- susceptible zones on a wider scale to preserve the quality and the productivity of affected agricultural areas.
Effects of adding dexmedetomidine, fentanyl, and verapamil to 0.5% ropivacaine on onset and duration of sensory and motor block in forearm surgeries
Authors: Hashemi Nazanin , Modir Hesameddin , Moshiri Esmail , Moradi Amir Hossein , Almasi-Hashiani Amir
Published: March 2021

This study was aimed to compare the onset and duration of axillary block with ropivacaine 0.5% plus either dexmedetomidine, fentanyl, or verapamil in forearm surgeries. This double-blind clinical trial enrolled three equal-sized block-randomized groups of patients (n = 105) scheduled for hand and forearm surgery at Arak, Iran in 2019, who received: (i) ropivacaine (40 mL/0.5%) + dexmedetomidine (1 μg/kg), (ii) ropivacaine (40 mL/0.5%) + fentanyl (1 μg/kg), and (iii) ropivacaine (40 mL/0.5%) + verapamil (2.5 mg), respectively. We recorded some vital signs such as mean arterial pressure, heart rate and oxygen saturation, onset of complete sensory and motor block, duration of the block, opioid use, as well as pain score at recovery and certain time points (2, 4, 6, 12, and 24 hours post-operation). Adding dexmedetomidine to ropivacaine (40 mL/0.5%) prolonged the duration of sensory (P = 0.001) and motor block (P = 0.001) in compared to adding fentanyl and verapamil and it also shortens the time to onset of sensory (P = 0.001) and motor block (P = 0.001). There is a significant difference between three groups in terms of visual analog scale mean and the lowest pain score was obtained in the dexmedetomidine group (P = 0.001), significant time trend (P = 0.001), as well as the time and groups interaction (P = 0.001). Dexmedetomidine was concluded to be associated with alleviated pain; reduced opioid use; short onset of sensory block; and prolonged duration of sensory and motor block. It hence is recommended to lengthen the duration of axillary block and to help relieve postoperative pain and ultimately to move to cut down the postoperative opioid use in forearm surgery. The study was approved by the Ethical Committee of Arak University of Medical Sciences (approval No. IR.ARAKMU. REC.1397.266), and registered on Iranian Registry of Clinical Trials (registration No. IRCT20141209020258N111) on May 9, 2019.
Vitamin D Correlation with Echocardiographic Function in Patients of Congestive Heart Failure
Authors: Mohanty Vivek , Pathania Monika , Bhasi Ankith
Published: March 2021

Background:

The association between vitamin D and heart failure, especially left ventricular (LV) function, is still not clear.

Objectives:

We aimed to study the correlation between 25-hydroxy vitamin D levels and parameters of cardiac systolic and diastolic functions in patients with LV systolic heart failure.

Materials and Methods:

Ninety patients of heart failure coming to our hospital with systolic heart failure (LV ejection fraction <40%) were included. Venous sample were taken for measurement of 25-hyrdoxy vitamin D levels. Transthoracic echocardiography was done for all patients, and parameters of LV systolic and diastolic functions were taken.

Results:

Compared to patients having vitamin D <20 ng/ml, patients having vitamin D levels ≥20 ng/ml had higher early diastolic mitral annular velocity (e'), significantly lower ratio of early diastolic mitral inflow velocity (E) to e' (E/e'), significantly shorter isovolumetric relaxation time (IVRT) suggestive of better diastolic function. Furthermore, patients having vitamin D <20 ng/ml had higher LV end-systolic volume, LV end-systolic diameter, larger LV end-diastolic diameter, higher interventricular septum thickness, higher LV wall thickness, and higher LV mass.

Conclusion:

Reduced vitamin D (<20 ng/ml) was associated with worse systolic function in terms of systolic volume and diameter, diastolic function in terms of lower e′, higher E/e′, and longer IVRT.
Diesel Fuel Injection Pump - Validation of Calibrating Nozzle Holder Assemblies
Authors:   Diesel Fuel Injection Equipment Standards Committee
Published: March 2021

The fuel injection pump is intended to validate the accuracy of calibrating nozzle and holder assemblies for applications using 0.4 - 0.8 mm diameter orifice plates and to assist in identifying problems in fuel injection pump test stands.

This SAE Recommended Practice is divided into two parts:

Part I—Design, Description and Specifications of the Fuel Injection Pump; and

Part II—Test Procedures for Using the Fuel Injection Pump.
Diversity of siderophore-producing bacterial cultures from Carlsbad Caverns National Park caves, Carlsbad, New Mexico
Authors: Duncan Tammi , Werner-Washburne Margaret , Northup Diana
Published: March 2021

Siderophores are microbially-produced ferric iron chelators. They are essential for microbial survival, but their presence and function for cave microorganisms have not been extensively studied. Siderophores are classified based on the common functional groups (catechols, hydroxamates, carboxylates, and mixed) that coordinate to ferric (Fe3+) iron. Cave environments are nutrient-limited and previous evidence suggests siderophore usage in carbonate caves. We hypothesize that siderophores are likely used as a mechanism in caves to obtain critical ferric iron. Cave bacteria were collected from long-term parent cultures (LT PC) or short-term parent cultures (ST PC) inoculated with ferromanganese deposits (FMD) and carbonate secondary minerals from Lechuguilla and Spider caves in Carlsbad Caverns National Park, NM. LT PC were incubated for 10−11 years to identify potential chemolithoheterotrophic cultures able to survive in nutrient-limited conditions. ST PC were incubated for 1−3 days to identify a broader diversity of cave isolates. A total of 170 LT and ST cultures, 18 pure and 152 mixed, were collected and used to classify siderophore production and type and to identify siderophore producers. Siderophore production was slow to develop (>10 days) in LT cultures with a greater number of weak siderophore producers in comparison to the ST cultures that produced siderophores in <10 days, with a majority of strong siderophore producers. Overall, 64% of the total cultures were siderophore producers, with the majority producing hydroxamate siderophores. Siderophore producers were classified into Proteobacteria (Alpha-, Beta-, or Gamma-), Actinobacteria, Bacteroidetes, and Firmicutes phyla using 16S rRNA gene sequencing. Our study supports our hypothesis that cave bacteria have the capability to produce siderophores in the subsurface to obtain critical ferric iron.
Differentiation of Two Pleurotus Species Based on the Restrictive Digestion Profile of the Internal Transcribed Spacer Region
Authors: Wiafe-Kwagyan M. , Odamtten G. T. , Obodai M.
Published: March 2021

Two oyster mushrooms (Pleurotus eous P-31 and P. ostreatus EM-1) are under either cottage industry or semi-commercial cultivation in Ghana. The latter (P. ostreatus) is already well known to the public and on the shelf of some leading supermarkets. There is morphological resemblance between the two species making it difficult for the untrained eye to distinguish between them except for the colour difference. In this study, molecular methods were em­ployed to differentiate among the two species. The Internal Transcribed Spacer ITS 1 and ITS 4 regions of the rDNA of the two oyster species were amplified by the conventional PCR using the universal primer pair, ITS 1 and ITS 4 followed by restrictive digestion with enzymes, (Hh I, Hinf I, Rsa I and Hae III). The two species could not be separated based on the ampli­fied bands only, as both produced a characteristic band size of 650 bp. Gel profiling showing restrictive patterns generated by the four enzymes indicated that only the Hae III restrictive enzyme was effective in separating P. eous P-31 and P. ostreatus EM-1. This is the first record of the separation of the Ghanaian Pleurotus species by molecular methods indicating their genetic differences.
Pedo-Transfer Functions for Predicting Total Soil Nitrogen in Different Land Use Types under Some Tropical Environments
Authors: Mesele S. A. , Ajiboye G. A.
Published: March 2021

Nitrogen pedo-transfer functions were developed for different land use types, soil depths and agro-ecologies across eight states in Nigeria. The results showed that total nitrogen had a good relationship with the soil organic carbon; therefore, the functions developed were based on the relationship between organic carbon and total nitrogen as other soil parameters (pH, and particle size distribution) had little contribution and no significant correlation (p>0.05) with total nitrogen. Correlation and forward stepwise regression and Kendall’s Coefficient Concordance were used to fit and validate the developed model with datasets other than those used for the model formulation. The R2 of the best fitted regression models varied from 0.77 to 0.85. We obtained a generalized fitted model (TN = 0.0736*OC, R2 = 0.83) which is independent of the agroecology and the land use types. Significant fitted models were also obtained for the arable farms (TN = 0.08*OC, R2 = 0.85) and the plantation farms (TN = 0.0698*OC, R2 = 0.83). It was discovered that variations in agro-ecology, land use, and soil depth did not significantly affect the model performance.
Biosorption of lead by bacteria isolated from abattoir wastewater
Authors: Abioye O. P , Nnadozie H.O , Aransiola S.A , Musa O. I.
Published: March 2021

Six bacteria were isolated from abattoir wastewater collected from Minna central abattoir. Lead tolerant bacteria were isolated from the wastewater. The isolates were then characterized on the basis of their colonial appearance and reaction to various biochemical tests. The lead tolerance profile of the isolates was carried out using agar diffusion method, with concentrations of Lead nitrate ranging from 50-250 mg/L. Two resistant isolates identified as species of Bacillus and Neisseria were selected for biosorption studies. Lead concentration was determined using Atomic Absorption Spectrophotometry. The lead biosorption capacity of the two isolates was studied by inoculating 2 mL of 24 hours old bacteria suspension in 50mL Nutrient broth, containing varying concentrations of lead (500 and 1000 mg/L) at varying pH (7 and 8), with representative samples being withdrawn at day 4, 8 and 12. The results showed that highest biosorption rate was recorded on day 10, at pH 7, in solution containing 500 mg/L of lead with 75.3% and 66% by Bacillus sp. and Neisseria sp. respectively. These results show that Bacillus sp. had better sorption capacity than Neisseria sp. Both organisms can be used for the removal of lead.

Keywords: Wastewater, Biosorption, Abattoir, heavy metal, Bacteria
Brittle material strength and fracture toughness estimation from four-point bending test
Authors: Doitrand Aurélien , Henry Ronan , Meille Sylvain
Published: March 2021

The failure stress under four-point bending cannot be considered as an intrinsic material property because of the well-known size effect of increasing maximum flexural stress with decreasing specimen size. In this work, four-point bending tests are analyzed with the coupled criterion for different sample sizes. The maximum flexural stress only tends towards the material tensile strength provided the specimen height is large enough as compared to the material characteristic length. In that case, failure is mainly driven by a stress criterion. Failure of smaller specimens is driven both by energy and stress conditions, thus depending on the material tensile strength and fracture toughness. Regardless of the material mechanical properties, we show that the variation of the ratio of maximum flexural stress to strength as a function of the ratio of specimen height to material characteristic length follows a master curve, for which we propose an analytical expression. Based on this relation, we propose a procedure for the post-processing of four-point bending tests that allows determining both the material tensile strength and fracture toughness. The procedure is illustrated based on four-point bending experiments on three gypsum at different porosity fractions.
An Analysis of the Views of Parents with Preschool Children in Relation to Science and Preschool Science Activities
Authors: Simsar Ahmet
Published: March 2021

Although much is known about children and teachers' attitudes towards science and science activities, considerably less is known about what parents believe about them. Parents' attitudes towards science and science activities are as important as teachers' role in influencing children’s achievement in science. In this study, parents’ views towards science and preschool science activities were investigated as to different variables. In this regard, descriptive research method was used in the study, which was conducted with 442 mothers (383) and fathers (59) with children aged between 3 and 6 years and attending preschool. ‘The Parents' Views about Science and Preschool Science Activities Scale (PaVSPeSAS)’ developed by Sahin, Uludağ, Gedikli, and Karakaya (2018) demographic information form developed by the researcher was used as the data collection tools in the study. Since the data were collected during the COVID-19 pandemic process, they were obtained by sharing with parents the scale link prepared on the online platform. The results showed that parents’ gender, age, educational background, the amount of time spent with children for kitchen activities have impacts on parents’ different views regarding science content.