Search in Publications
Found 6319 publications
Comparison of monocultures and a mixed culture of three Chlorellaceae strains to optimize biomass production and biochemical content in microalgae grown in a greenhouse
Publication Name: Journal of Applied Phycology
Publication Date: 2021-10-01
Volume: 33
Issue: 5
Page Range: 2755-2766
Description:
Light and temperature are important environmental conditions affecting microalgal growth in outdoor culture. It is essential to evaluate microalgae strains growing under outdoor conditions where they are subjected to variable environmental parameters. The present study investigated three Chlorellaceae strains (Micractinium sp. MACC-728, Chlorella sorokiniana MACC-438, and C. sorokiniana MACC-452) and a mixed culture combining these three strains. Cultures were grown in 2-L bioreactors in a greenhouse over 3 months to assess the effects of high temperature and light on their growth, macromolecule content, and antioxidant and plant-stimulating bioactivities. The most influential environmental parameters on growth were average air temperature and the sum of photosynthetically active radiation, followed by maximum air temperature. The most affected growth parameter was daily change in cell number. Chlorella sorokiniana MACC-438 produced the lowest biomass and was most affected by the high temperature and light conditions. Micractinium sp. produced the highest biomass and was least affected, suggesting it was the most suitable strain for outdoor cultivation. The mixed Chlorellaceae culture performed well in biomass production, exceeding C. sorokiniana monocultures but significantly underyielding in lipid content. Antioxidant activity and the root-stimulating activity varied with strain and culture age. Micractinium sp. had the highest but most variable antioxidant and plant-stimulating activity. Bioactivity in the mixed culture was more consistent, remaining high regardless of culture age and environmental conditions. Thus, mixed cultures of productive strains could be a useful strategy to ensure stable and high-quality biomass production in outdoor cultivation with fluctuating environmental conditions.
Open Access: Yes
Rise and fall of Stachys annua (L.) L. in the Carpathian Basin: a historical review and prospects for its revival
Publication Name: Genetic Resources and Crop Evolution
Publication Date: 2021-10-01
Volume: 68
Issue: 7
Page Range: 3039-3053
Description:
Stachys annua (L.) L., a melliferous archaeophyte plant became a dominant weed of the cereal stubbles of the Carpathian Basin in the medieval three-field system. By the middle of the nineteenth century, this plant provided more than two-thirds of the Hungarian honey production, and its high quality monofloral honey turned into a characteristic brand of the Hungarian apiculture. Recognizing its importance, S. annua also briefly became a minor crop cultivated in “bee gardens” and arable fields in the late nineteenth century, possibly also in response to the first signs of its upcoming decline. Starting with the advent of the steam plough, the twentieth century has brought a drastic decline for S. annua due to a combination of deeper and earlier tillage operations, agrochemicals, and new competing weed species (in particular the common ragweed, Ambrosia artemisiifolia). The last remnant stands of this previously dominant weed species are of considerable ecological and historical value as farmland biodiversity hotspots. These sites are important refuge for rare weeds, wild pollinators (including bumblebees), and declining farmland birds, which could be targeted by eco-schemes under the European Union’s (EU’s) greening Common Agricultural Policy. The rediscovery of the cropping potential of S. annua and the development of an appropriate technology would also allow its cultivation as a valuable bee forage, catch crop, green cover, or oilseed plant in the future.
Open Access: Yes
Online Communication of Local Governments During COVID-19 Pandemic in Hungary
Publication Name: Frontiers in Political Science
Publication Date: 2021-09-29
Volume: 3
Issue: Unknown
Page Range: Unknown
Description:
Local governments had key and prominent roles in tackling the COVID-19 pandemic. Their task was to take short-term measures quickly and to organize protection and care for those in need. The main objective of our paper is to present how local governments communicated with their inhabitants on various online interfaces in this crisis situation. Our analysis covers 54 settlements representing all the different levels of the settlement network from large cities to small villages. We examined the webpages and Facebook pages of local governments and mayors, first during the first wave and then during the second and third waves of the pandemic. Recognizing their responsibility, local governments clearly tried to provide information to the inhabitants as quickly as possible. They considered the online interfaces the most effective, but the online communication had typically been complemented by information published on more traditional channels as well. There were no significant differences in terms of the way and characteristics of communication among the different types of settlements, although local governments of different sizes obviously had to face different challenges in terms of the amount of tasks they had to tackle. The communication process was a very difficult task because of the lack of information and the not-transparent data provision. Even on the Facebook pages especially suitable for this purpose, interactivity rumbled, and in many cases the questions and suggestions of the inhabitants remained unanswered. It is instructive that, with few exceptions, settlements do not place emphasis on surveying local needs and opinions.
Open Access: Yes
An Analysis of Personalized Learning Opportunities in 3D VR
Publication Name: Frontiers in Computer Science
Publication Date: 2021-09-20
Volume: 3
Issue: Unknown
Page Range: Unknown
Description:
Due to its constantly developing technological background, VR and AR technology has been gaining increasing popularity not just in industry or business but in education as well. Research in the field of Cognitive Infocommunications (CogInfoCom) shows that using existing digital technologies, online collaboration and cooperation technologies in 3D VR supports cognitive processes, including the finding, processing, memorization and recalling of information. 3D VR environments are also capable of providing users with a much higher level of comprehension when it comes to sharing and interpreting digital workflows. The paper presents a study carried out with the participation of 90 students. The aim of this study is to investigate how the application of 3D VR platforms as personalized educational environments can also increase VR learning efficiency. Besides considering participants’ test performance, metrics such as results on visual, auditory and reading-based learning tests for information acquisition, as well as responses on Kolb’s learning styles questionnaires are taken into consideration. The participants’ learning styles, information acquisition habits were also observed, allowing us to create and offer a variety of learning pathways based on a variety of content types in the 3D VR environment. The students within the study were divided into two groups: a test group receiving personalized training in the MaxWhere 3D VR classroom, and a control group that studied in a general MaxWhere 3D VR space. This research applies both quantitative and qualitative methods to report findings. The goal was to create adaptive learning environments capable of deriving models of learners and providing personalized learning experiences. We studied the correlation between effectiveness of the tasks and Kolb’s learning styles. The study shows the major importance of choosing the optimal task type regarding each Kolb learning style and personalized learning environment. The MaxWhere 3D spaces show a high potential for personalizing VR education. The non-intrusive guiding capabilities of VR environments and of the educational content integrated in the 3D VR spaces were very successful, because the students were able to score 20 percent higher on the tests after studying in VR than after using traditional educational tools. Students also performed the same tasks with 8-10 percent faster response times.
Open Access: Yes
On classical and fuzzy Hough transform in colonoscopy image processing
Publication Name: IEEE AFRICON Conference
Publication Date: 2021-09-13
Volume: 2021-September
Issue: Unknown
Page Range: Unknown
Description:
Hough transform is used to find lines on edge-filtered images that are given in parametric form. As the fuzzy extension of the Hough transform has been proven to be more robust in environments where the lines to be found by them are not strictly following the formula given by the parametric equation of the Hough transform due to noise and weak and blurred contours, in the following considerations, we study the applicability of the circular fuzzy Hough transform for analyzing colonoscopy pictures and detecting colorectal polyps.
Open Access: Yes
Genetic parameters of gestation length trait in dromedary camels (Camelus dromedarius)
Publication Name: Acta Veterinaria Hungarica
Publication Date: 2021-09-03
Volume: 69
Issue: 3
Page Range: 249-255
Description:
Gestation length (GL) data of dromedary camels were analysed for the period from 2007 to 2018. The database of the largest dairy camel herds (Dubai, United Arab Emirates) was used in this study. The data of 4,084 camels included in the assessment were classified into six ecotypes (Emirati, Emirati cross, Black, Pakistani, Saudi-Sudanese and Saudi cross). The aim of the study was to describe the heritability of GL of camels and the breeding value (BV) of sires for this trait. The genetic parameters of GL were estimated by the General Linear Model method and two Best Linear Unbiased Prediction (BLUP) animal models as well. The mean (±SE) of GL of camels was 384.3 ± 0.2 days. The direct heritability of GL (0.26 ± 0.06-0.36 ± 0.08) was higher than the maternal heritability (0.00 ± 0.05-0.13 ± 0.06) obtained. The maternal permanent environmental effect (0.15 ± 0.05) was similar to the results estimated previously in dromedary camel, but higher than the data reported by relevant sources in other species. Based on the results of this study it can be concluded that the GL of dromedary camels is a species-specific value similar to that in cattle, which is less affected by the maternal influence. Considerable differences (16 days) exist among male dromedaries in their BV for the GL trait.
Open Access: Yes
Utilization of Waste Marble Dust in Poly(Lactic Acid)-Based Biocomposites: Mechanical, Thermal and Wear Properties
Publication Name: Journal of Polymers and the Environment
Publication Date: 2021-09-01
Volume: 29
Issue: 9
Page Range: 2952-2963
Description:
The aim of this present work was to study the applicability of waste marble dust (MD) in poly(lactic acid) (PLA)-based composites. Samples containing up to 20 wt% waste MD were prepared via melt blending. The attention was focused on the investigation of mechanical, morphological, thermal properties and the wear resistance of the PLA/MD composites. Regarding the mechanical properties, both the tensile and the flexural modulus improved remarkably, however, a slight loss was observed in strength and deformability. The impact toughness showed an increasing tendency up to 10 wt% MD loading, which was followed by a marginal decrease at higher concentration. With respect to the sliding wear rate, the composite with the highest MD content showed the best wear resistance. According to the DSC measurements, the MD hampered the chain mobility of PLA, thereby reducing the crystalline ratio. Overall, composites with improved properties were developed, while the reuse of waste MD is expected to reduce the production costs as well.
Open Access: Yes
Physical, mechanical, and thermal properties of Dalbergia sissoo wood waste-filled poly(lactic acid) composites
Publication Name: Polymer Composites
Publication Date: 2021-09-01
Volume: 42
Issue: 9
Page Range: 4380-4389
Description:
The present work intended to investigate the effect of Dalbergia sissoo wood waste on physical, mechanical, and thermal properties of poly(lactic acid) (PLA)-based composites. The composite specimens, containing wood waste (2.5%, 5%, 7.5%, and 10% by weight) mixed with PLA granules, were prepared by melt compounding. It was found that increased wood waste content resulted in higher modulus, porosity, and water absorption with decreased density, tensile strength, impact strength, and stress at break. Nevertheless, the flexural strength values of the composites were similar to unfilled PLA and they remained almost constant irrespective of the wood waste content. Differential scanning calorimetry analysis revealed that the presence of wood waste content increased the glass transition and cold crystallization temperature of the PLA composites. Moreover, the fractured surfaces of the composites were examined with a scanning electron microscope to study the possible failure mechanisms. The conducted investigations demonstrated that low-cost wood waste-based composites can be used as an environmentally and economically attractive substitute for lightweight applications.
Open Access: Yes
DOI: 10.1002/pc.26155
Analysis of socio-economic spatial structure of urban agglomeration in China based on spatial gradient and clustering
Publication Name: Oeconomia Copernicana
Publication Date: 2021-09-01
Volume: 12
Issue: 3
Page Range: 789-819
Description:
Research background: Previous studies on the economic and social development of urban agglomerations mostly focus on a single primacy comparative analysis and efficiency evaluation. Spatial structure differentiation is an important feature of urban agglomeration. The lack of economic and social analysis on the spatial structure makes it impossible to determine the development positioning of each city in the urban agglomeration, which affects the sustainable economic devel-opment ability of these areas. Purpose of the article: The objective of the article is to analyze the spatial development law and experience of urban agglomeration, this study explores the practice of economic and population spatial structure of city areas in China. For this purpose, CPUA and its central city Zhengzhou was taken as an example, the spatial gradient structure of example was analyzed. Methods: Using economic and population data of 32 cities in this region, growth pole theory, and pole-axis theory, the economic and population spatial structure of urban agglomeration, the spatial gradient structure of central cities in urban agglomerations were analyzed with the method of cluster about radiation index. Findings & value added: (1) In the process of the formation of CPUA, the geo-graphical spatial pattern plays a decisive role in economic and social development. This is an experience from developing countries. (2) CPUA presents a gradient development pattern with Zhengzhou as the center, and economic and social development gradually radiates to the metropolitan area, the core development area, and the character development demonstration area. (3) The economic and social gradients of Zhengzhou, the central city, present the hierarchy rules and characteristics which are driven by the Beijing-Guangzhou-Railway axis and the Longhai-Railway axis. (4) The central city of Zhengzhou still presents insufficient primacy in regional development, which shows that Zhengzhou accounts for 6% of the population of the Central Plains Economic Zone and 14% of GDP, and insufficient agglomeration. Different countries at different stages of economic development have different urban agglomeration development models. The conclusions from China provide new decision-making ideas and methods for spatial structure research and development strategy analysis of urban agglomerations.
Open Access: Yes
DOI: 10.24136/OC.2021.026
