Search results for: seed yield

Authors: Jerome E. Abiemo, Takeshi Mizunoya

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The Aveyime community in the Volta region of Ghana is one of the major hubs for rice production. In the past, rice farmers applied organic pesticides to control pests, and compost as a soil amendment to improve fertility and productivity. However, the introduction of chemical pesticides and fertilizers have led many farmers to convert to inorganic system of rice production, without considering the social costs (e.g. groundwater contamination and health costs) related to the use of pesticides. The study estimates and compares the private and social BCRs of organic and inorganic systems of rice production. Both stratified and simple random sampling techniques were employed to select 300 organic and inorganic rice farmers and 50 pesticide applicators. The respondents were interviewed with pre-tested questionnaires. The Contingent Valuation Method (CVM) which elucidates organic farmers` Willingness-to-Pay (WTP) was employed to estimate the cost of groundwater contamination. The Cost of Illness (COI) analysis was used to estimate the health cost of pesticide-induced poisoning of applicators. The data collated, was analyzed with the aid of Microsoft excel. The study found that high private benefit (e.g. increase in farm yield and income) was the most influential factor for the rapid adoption of pesticides among rice farmers. The study also shows that the social costs of inorganic rice production were high. As such the social BCR of inorganic farming (0.2) was low as compared to organic farming (0.7). Based on the results, it was recommended that government should impose pesticide environmental tax, review current agricultural policies to favour organic farming and promote extension education to farmers on pesticide risk, to ensure agricultural and environmental sustainability.

Keywords: benefit-cost-ratio (BCR), inorganic farming, pesticides, social cost

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Authors: Paula Buldres, Jorge Toledo

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Objectives: This study aimed to characterize potential probiotic strains isolated from canine breast milk for use in dogs with enteropathies. Methodology: Six canine breast milk strains, one canine colostrum strain, and one control porcine breast milk strain were characterized. According to its functional properties of resistance to acids, different concentrations of bile salts, and pancreatin, its presumptive properties of safety and inhibitory effect on pathogens, non-cytotoxic characteristics, and adhesion to the intestine. The immunomodulatory effect of formulations with better probiotic characterization in vitro and in vivo was also analyzed. Results: Two strains characterized as potential probiotics were obtained, which corresponded to the canine strains (TUCO-16 and TUCO-17), presenting resistance to acidic pH, bile salts, and pancreatin, as well as an inhibitory effect on pathogenic Escherichia coli, Salmonella sp., and Clostridium perfringens. Strains TUCO-16 and TUCO-17 induced a significant increase in the expression of TNF-α and IL-8 in canine macrophages, respectively. Expression analyses of pattern recognition receptors in DH82 cells suggest that TUCO-16 and TUCO-17 might increase the TLR2 expression marker, and porcine strain (TUCO-4) increases the NOD2 expression marker. Based on the count obtained and the encapsulation yield, the best formulations correspond to FOS-Inulin for the TUCO-17 and TUCO-4 strains; Maltodextrin-Inulin for TUCO-16. All the strains are non-cytotoxic. The strain that showed the highest adhesion to intestinal epithelial cells was TUCO-17 with the FOS-Inulin formulation. On the other hand, the probiotics decreased the expression of pro-inflammatory markers in vivo, both in the intestine and in the spleen of mice. Conclusion: The combination of these three strains under study (TUCO-16, TUCO-17, and TUCO-4) would cover the probiotic properties in formulation and immunomodulation of all the markers under study.

Keywords: probiotics, gastrointestinal infec, dog, probiotic formulation, immunomodulatory probiotics

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Authors: Julia Brudzinski, Ashley Croswell, Jade Mardin, Hannah Shilling, Jennifer Berg-Carnegie

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Adults with brain injuries and mental illnesses commonly experience cognitive impairments that interfere with their participation in activities of daily living (ADLs). Prior research states that electronic reminder systems can support adults with cognitive impairments; however, previous studies focus primarily on one-way reminder systems. Research on adults with chronic diseases reported that two-way reminder systems yield better health outcomes and disease self-management compared to one-way reminder systems. Literature was identified through systematically searching 7 databases and hand-searching relevant reference lists. Retrieved studies were independently screened and reviewed by at least two members of the research team. Data was extracted on study design, participant characteristics, intervention details, study objectives, outcome measures, and important results. 574 articles were screened and reviewed. Nine articles met all inclusion criteria and were included. The literature focused on three main areas: system feasibility (n=8), stakeholder satisfaction (n=6), and efficacy of the two-way reminder systems (n=6). Participants in eight of the studies had brain injuries, with participants in only one study having a mental illness (i.e., schizophrenia). Two-way reminder systems were used to support participation in a wide range of ADLs. The current literature on two-way reminder systems to support ADLs for adults with cognitive impairments focuses on feasibility, stakeholder satisfaction, and system efficacy. Future research should focus on addressing the barriers to accessing and implementing two-way reminder systems and identifying specific client characteristics that would benefit most from using these systems.

Keywords: brain injury, digital health, occupational therapy, activities of daily living, two-way reminder systems

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Authors: Mireille Vonlanthen, Pasquale Porcu, Ernesto Rivera

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Dendritic macromolecules are presenting unique physical and chemical properties. One of them is the faculty of transferring energy from a donor moiety introduced at the periphery to an acceptor moiety at the core, mimicking the antenna effect of the process of photosynthesis. The mechanism of energy transfer is based on the Förster resonance energy exchange and requires some overlap between the emission spectrum of the donor and the absorption spectrum of the acceptor. Since it requires a coupling of transition dipole but no overlap of the physical wavefunctions, the energy transfer by Förster mechanism can occur over quite long distances from 1 to a maximum of 10 nm. However, the efficiency of the transfer depends strongly on distance. The Förster radius is the distance at which 50% of the donor’s emission is deactivated by FRET. In this work, we synthesized and characterized a novel series of dendrimers bearing pyrene moieties at the periphery and a Ru (II) complex at the core. The optical and photophysical properties of these compounds were studied by absorption and fluorescence spectroscopy. Pyrene is a well-studied chromophore that has the particularity to present monomer as well as excimer fluorescence emission. The coordination compounds of Ru (II) are red emitters with low quantum yield and long excited lifetime. We observed an efficient singulet to singulet energy transfer in such constructs. Moreover, it is known that the energy of the MLCT emitting state of Ru (II) can be tuned to become almost isoenegetic with respect to the triplet state of pyrene, leading to an extended phosphorescence lifetime. Using dendrimers bearing pyrene moieties as ligands for Ru (II), we could combine the antenna effect of dendrimers as well as its protection effect to the quenching by dioxygen with lifetime increase due to triplet-triplet equilibrium.

Keywords: dendritic molecules, energy transfer, pyrene, ru-trisbipyridine complex

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Authors: Dharmendra Pratap

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Large Cardamom (Amomum subulatum), family Zingiberaceae is an aromatic spice crop and has rich medicinal value. Large Cardamom is as synonymous to Sikkim as Tea is to Darjeeling. Since Sikkim alone contributes up to 88% of India's large cardamom production which is the world leader by producing over 50% of the global yield. However, the production of large cardamom has declined almost to half since last two decade. The economic losses have been attributed to two viral diseases namely, chirke and Foorkey. Chirke disease is characterized by light and dark green streaks on leaves. The affected leaves exhibit streak mosaic, which gradually coalesce, turn brown and eventually dry up. Excessive sprouting and formation of bushy dwarf clumps at the base of mother plants that gradually die characterize the foorkey disease. In our surveys in Sikkim–Darjeeling hill area during 2012-14, 40-45% of plants were found to be affected with foorkey disease and 10-15% with chirke. Mechanical and aphid transmission study showed banana as an alternate host for both the disease. For molecular identification, total genomic DNA and RNA was isolated from the infected leaf tissues and subjected to Rolling circle amplification (RCA) and RT-PCR respectively. The DNA concatamers produced in the RCA reaction were monomerized by different restriction enzymes and the bands corresponding to ~1 kb genomes were purified and cloned in the respective sites. The nucleotide sequencing results revealed the association of Nanovirus with the foorkey disease of large cardamom. DNA1 showed 74% identity with Replicase gene of FBNYV, DNA2 showed 77% identity with the NSP gene of BBTV and DNA3 showed 74% identity with CP gene of BBTV. The finding suggests the presence of a new species of nanovirus associated with foorkey disease of large cardamom in Sikkim and Darjeeling hills. The details of their epidemiology and other factors would be discussed.

Keywords: RCA, nanovirus, large cardamom, molecular virology and microbiology

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Authors: Daniel Afolayan, Christina Olawepo, Francis Olowookanga, Nguhemen Tingir, Olawale Fadare, John Oko

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In Nigeria, traditional birth attendants (TBAs) can play an important role in the prevention of mother-to-child transmission of HIV. However, their role in improving access to antiretroviral therapy (ART) is unclear. Catholic Caritas Foundation of Nigeria (Caritas Nigeria) is an implementing agency supporting increased access to HIV testing and treatment services in Lagos state through health facilities including Mother Theresa Hospital. Despite intra-facility testing and community outreaches, ART uptake at Mother Theresa Hospital, Lagos was low with 6 individuals on antiretroviral drugs 3 months post-activation. This study explored improving access to ART through linkages with TBAs for ART uptake at the facility. Plan-Do-Study-Act model was used. The goal was to improve uptake of ART from 6 to 80 in 5 months (end of project year). Scanning revealed a network of 15 TBAs with potential as satellites for HIV testing. Caritas Nigeria linked the facility with 15 TBAs who were provided with HIV test kits and trained on HIV testing services for provider-initiated testing and outreaches. Weekly reports and referrals of positives were received, tracked and feedback given on testing yield. These TBAs serve individuals of various age and gender at their trado-medical centres. At the end of 5 months, HIV testing increased by 10,575 (78% from TBAs) and HIV positives obtained improved by 77 (44.2% from TBAs). 55 new individuals were enrolled and commenced on ART (61.8% from TBAs). There was a successful linkage of all clients with escort services due to incentives. Total uptake of ART was 61 (76.3% of target). Structured partnerships between TBAs and HIV care and treatment centers should be strengthened to improve access to ART.

Keywords: access improvement, antiretroviral therapy, traditional birth attendants, uptake

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Authors: Jeff Chak-Fu Wong, Tony Chun Yin Yip

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The transition from secondary school to university seems exciting for many first-year students but can be more challenging than expected. Enabling instructors to know students’ learning habits and styles enhances their understanding of the students’ learning backgrounds, allows teachers to provide better support for their students, and has therefore high potential to improve teaching quality and learning, especially in any mathematics-related courses. The aim of this research is to collect students’ data using online surveys, to analyze students’ factors using learning analytics and educational data mining and to discover the characteristics of the students at risk of falling behind in their studies based on students’ previous academic backgrounds and collected data. In this paper, we use correlation-based distance methods and mutual information for measuring student factor relationships. We then develop a factor network using the Minimum Spanning Tree method and consider further study for analyzing the topological properties of these networks using social network analysis tools. Under the framework of mutual information, two graph-based feature filtering methods, i.e., unsupervised and supervised infinite feature selection algorithms, are used to analyze the results for students’ data to rank and select the appropriate subsets of features and yield effective results in identifying the factors affecting students at risk of failing. This discovered knowledge may help students as well as instructors enhance educational quality by finding out possible under-performers at the beginning of the first semester and applying more special attention to them in order to help in their learning process and improve their learning outcomes.

Keywords: students' academic performance, correlation-based distance method, social network analysis, feature selection, graph-based feature filtering method

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Authors: Pius Borona, Cheikh Mbow, Issa Ouedraogo

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In the Sahel, climate variability has been associated with a complex web of direct and indirect impacts. This natural phenomenon has been an impediment to agro-pastoral communities who experience uncertainty while involving in farming activities which is also their key source of livelihood. In this scenario, the role of climate variability in influencing the performance, quantity and quality of staple cereals yields, vital for food and nutrition security has been a topic of importance. This response of crops and subsequent yield variability is also a subject of immense debate due to the complexity of crop development at different stages. This complexity is further compounded by influence of slowly changing non-climatic factors. With these challenges in mind, the present paper initially explores the occurrence of climate variability at an inter annual and inter decadal level in South Burkina Faso. This is evidenced by variation of the total annual rainfall and the number of rainy days among other climatic descriptors. Further, it is shown how district-scale cereal yields in the study area including maize, sorghum and millet casually associate variably to the inter-annual variation of selected climate variables. Statistical models show that the three cereals widely depict sensitivity to the length of the growing period and total dry days in the growing season. Maize yields on the other hand relate strongly to the rainfall amount variation (R2=51.8%) showing high moisture dependence during critical growth stages. Our conclusions emphasize on adoption of efficient water utilization platforms especially those that have evidently increased yields and strengthening of forecasts dissemination.

Keywords: climate variability, cereal yields, seasonality, rain fed farming, Burkina Faso, rainfall

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Authors: András Farkas, István Molnár, Jan Vrána, Veronika Burešová, Petr Cápal, András Cseh, Márta Molnár-Láng, Jaroslav Doležel

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Species of Aegilops played a central role in the evolution of wheat and are sources of traits related to yield quality and tolerance against biotic and abiotic stresses. These wild genes and alleles are desirable to use in crop improvement programs via introgressive hybridization. However, the success of chromosome mediated gene transfer to wheat are hampered by the pour knowledge on the genome structure of Aegilops relative to wheat and by the low number of cost-effective molecular markers specific for Aegilops chromosomes. The COS markers specific for genes conserved throughout evolution in both sequence and copy number between Triticeae/Aegilops taxa and define orthologous regions, thus enabling the comparison of regions on the chromosomes of related species. The present study compared individual chromosomes of Aegilops umbellulata (UU), Ae. comosa (MM), Ae. speltoides (SS) and Ae. caudata (CC) purified by flourescent labelling with oligonucleotid SSR repeats and biparametric flow cytometry with wheat by identifying orthologous chromosomal regions by COS markers. The linear order of bin-mapped COS markers along the wheat D chromosomes was identified by the use of chromosome-specific sequence data and virtual gene order. Syntenic regions of wheat identifying genome rearrangements differentiating the U, M, S or C genomes from the D genome of wheat were detected. The conserved orthologous set markers assigned to Aegilops chromosomes promise to accelerate gene introgression by facilitating the identification of alien chromatin. The syntenic relationships between the Aegilops species and wheat will facilitate the targeted development of new markers specific for U, M, S and C genomic regions and will contribute to the understanding of molecular processes related to the evolution of Aegilops.

Keywords: Aegilops, cos-markers, flow-sorting, wheat

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Authors: Smriti, Ajeet Kumar

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We present a variant of the Irving-Kirkwood procedure to obtain the microscopic expressions of the cross-section averaged continuum fields such as internal force and moment in one-dimensional nanostructures in the non-equilibrium setting. In one-dimensional continuum theories for slender bodies, we deal with quantities such as mass, linear momentum, angular momentum, and strain energy densities, all defined per unit length. These quantities are obtained by integrating the corresponding pointwise (per unit volume) quantities over the cross-section of the slender body. However, no well-defined cross-section exists for these nanostructures at finite temperature. We thus define the cross-section of a nanorod to be an infinite plane which is fixed in space even when time progresses and defines the above continuum quantities by integrating the pointwise microscopic quantities over this infinite plane. The method yields explicit expressions of both the potential and kinetic parts of the above quantities. We further specialize in these expressions for helically repeating one-dimensional nanostructures in order to use them in molecular dynamics study of extension, torsion, and bending of such nanostructures. As, the Irving-Kirkwood procedure does not yield expressions of stiffnesses, we resort to a thermodynamic equilibrium approach to obtain the expressions of axial force, twisting moment, bending moment, and the associated stiffnesses by taking the first and second derivatives of the Helmholtz free energy with respect to conjugate strain measures. The equilibrium approach yields expressions independent of kinetic terms. We then establish the equivalence of the expressions obtained using the two approaches. The derived expressions are used to understand the extension, torsion, and bending of single-walled carbon nanotubes at non-zero temperatures.

Keywords: thermoelasticity, molecular dynamics, one dimensional nanostructures, nanotube buckling

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Authors: Wencong Lu, Abdul Latif, Raza Ullah, Subhan Ullah

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Agricultural production is subject to risk and the attitudes of producers toward risk, in turn, may be affected by certain socioeconomic characteristics of producers. Although, it is important to assess the risk attitude of farmers and their perception towards different calamitous risk sources for better understanding of their risk management adoption decisions, to the best of our knowledge no studies have been carried out to analyze the risk attitude and risk perceptions in the context of tobacco production in Pakistan. Therefore the study in hand is conducted with an attempt to overcome the gap in existing literature by analyzing different catastrophic risk sources faced by tobacco growers, their attitude towards risk and the effect of socioeconomic and demographic characteristics, farmers’ participation in contract farming and off-farm diversification on their risk attitude and risk perception. Around 78% of Pakistan’s entire tobacco crop and nearly all of the country’s Flue-Cured Virginia (FCV) tobacco is produced in Khyber Pakhtunkhwa (KPK) province alone. The yield/hectare of tobacco produced in KPK province is 14% higher than the global average and 22 % higher than national average. Khyber Pakhtunkhwa province was selected as main study area as nearly all of the country’s Flue-Cured Virginia (FCV) tobacco is produced in Khyber Pakhtunkhwa (KPK) province alone. Six districts were purposely selected based on their contribution in overall production for the last five years which accounts for more than 94.84% of the tobacco production in KPK province. Specific objectives taken into considerations for this study are the risk attitude of the farmers for growing FCV tobacco crop, farmers’ risk perception for different risk sources related to tobacco production (as far as the incidence and severity of each risk source is concerned) and the effect of socioeconomic characteristics, contract farming participation and off-farm diversification (income) on the risk attitude and risk perception of FCV tobacco growers.

Keywords: risk attitude, risk perception, contract farming, off-farm diversification, probit model

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Authors: Azadeh Yasari, Michael Ganzle, Stephen Strelkov, Nuanyi Liang, Jonathan Curtis, Nat N. V. Kav

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Pathogenic fungi cause significant yield losses and quality reductions to major crops including wheat, canola, and barley. Toxic metabolites produced by phytopathogenic fungi also pose significant risks to animal and human health. Extensive application of synthetic fungicides is not a sustainable solution since it poses risks to human, animal and environmental health. Unsaturated fatty acids may provide an environmentally friendly alternative because of their direct antifungal activity against phytopathogens as well as through the stimulation of plant defense pathways. The present study assessed the in vitro and in vivo efficacy of two hydroxy fatty acids, coriolic acid and ricinoleic acid, against the phytopathogens Fusarium graminearum, Pyrenophora tritici-repentis, Pyrenophora teres f. teres, Sclerotinia sclerotiorum, and Leptosphaeria maculans. Antifungal activity of coriolic acid and ricinoleic acid was evaluated using broth micro-dilution method to determine the minimum inhibitory concentration (MIC). Results indicated that both ricinoleic acid and coriolic acid showed antifungal activity against phytopathogens, with the strongest inhibitory activity against L. maculans, but the MIC varied greatly between species. An antifungal effect was observed for coriolic acid in vivo against pathogenic fungi of wheat and barley. This effect was not correlated to the in vitro activity because ricinoleic acid with equivalent in vitro antifungal activity showed no protective effect in vivo. Moreover, neither coriolic acid nor ricinoleic acid controlled fungal pathogens of canola. In conclusion, coriolic acid inhibits some phytopathogens in vivo and may have the potential to be an effective crop protection agent.

Keywords: coriolic acid, minimum inhibitory concentration, pathogenic fungi, ricinoleic acid

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Authors: Irshad Ali Khan, Jian-Ping Lu, Xiao-Hong Liu, Fu-Cheng Lin

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This study reports the functional analysis of a gene MoNUC1 in M. oryzae, which is homologous to the Saccharomyces cerevisiae NUC1 encoding a mitochondrial nuclease protein. The MoNUC1 having a gene locus MGG_05324 is 1002-bp in length and encodes an identical protein of 333 amino acids. We disrupted the gene through gene disruption strategy and isolated two mutants confirmed by southern blotting. The deleted mutants were then used for phenotypic studies and their phenotypes were compared to those of the Guy-11 strain. The mutants were first grown on CM medium to find the effect of MoNUC1 gene disruption on colony growth and the mutants were found to show normal culture colony growth similar to that of the Guy-11 strain. Conidial germination and appressorial formation were also similar in both the mutants and Guy-11 strains showing that this gene plays no significant role in these phenotypes. For pathogenicity, the mutants and Guy-11 mycelium blocks were inoculated on blast susceptible barley seedlings and it was found that both the strains exhibited full pathogenicity showing coalesced and necrotic blast lesions suggesting that this gene is not involved in pathogenicity. Mating of the mutants with 2539 strain formed numerous perithecia showing that MoNUC1 is not essential for sexual reproduction in M. oryzae. However, the mutants were found to form reduced conidia (1.06±8.03B and 1.08±9.80B) than those of the Guy-11 strain (1.46±10.61A) and we conclude that this protein is not required for the blast fungus to cause pathogenicity but plays significant role in conidiation. Proteins of signal transduction pathways that could be disrupted/ intervened genetically or chemically could lead to antifungal products of important fungal cereal diseases and reduce rice yield losses. Tipping the balance toward understanding the whole of pathogenesis, rather than simply conidiation will take some time, but clearly presents the most exciting challenge of all.

Keywords: appressorium formation, conidiation, NUC1, Magnaporthe oryzae, pathogenicity

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Authors: Yihunie Hibstie Asres, Manny Mathuthu

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Farmers may not be conscious for their farmland’s nutrients, soil organic matter, water and air because they simply concerned only for their labor availability and soil fertility losses. The composition and proportion of these components greatly influence soil physical properties, including texture, structure, and porosity, the fraction of pore space in a soil. The soil of this farmland must be able to supply adequate amount of plant nutrients, in forms which can be absorbed by the crop, within its lifespan. Deficiencies or imbalances in the supply of any of essential elements can compromise growth, affecting root development, cell division, crop quality, crop yield and resistance to disease and drought. This study was conducted to fill this knowledge gap in order to develop economically vital and environmentally accepted nutrient management strategies for the use of soils in agricultural lands. The objective of this study is to assess the elemental contents and concentration of soil samples collected from farmlands of ‘Yebrage’ using Neutron Activation Analysis (NAA) techniques regardless of oxidation state, chemical form or physical locations. NAA is used to determine the elemental composition and concentrations present in a soil. The macro/micronutrient and organic matter deficiencies have been verified in agricultural soils through increased use of soil testing and plant analysis. The challenge for agriculture over the coming decades will meet the world’s increasing demands for food in a sustainable way. Current issues and future challenges point out that as long as agriculture remains a soil-based industry, major decreases in productivity likely to be attained ensuring that plants do not have adequate and balanced supply of nutrients.

Keywords: NAA, Yebrage, Chemoga, macro/micronutrient

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Authors: Othmane Essahili, Mohamed Ilsouk, Carine Duhayon, Omar Moudam

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Due to their excellent and promising properties, a great deal of attention has recently been devoted to luminescent materials, particularly those utilizing rare earth elements. These materials play an essential role in low-cost energy conversion technology applications, such as luminescent solar concentrators (LSCs). They also have potential applications in Agri-PV systems and smart building windows. Luminescent materials based on europium (III) complexes are known for their high luminescence efficiency, long fluorescence lifetimes, and sharp emission bands. However, they present certain drawbacks related to their limited absorption capacity due to the forbidden 4f-4f electronic transitions. To address these drawbacks, using β-diketonate ligands as sensitizers appears as a promising solution to enhance luminescence intensity through the antenna effect, where the ligand's excited energy is transferred to the europium ions. In this study, we synthesized β-diketonate-based europium complexes with phenanthroline derivatives, modified with various methyl groups, to examine their effects on the complexes' stability in poly(methyl methacrylate) (PMMA) films. Our findings reveal that these complexes exhibit remarkable red emission and high photoluminescence quantum yield. Stability tests under different conditions for 1200 hours showed that complexes with a higher number of methyl substitutions offer improved photoluminescent stability and resistance to degradation, particularly in outdoor settings. This research underscores the potential of chemically tuned phenanthroline ligands in developing stable, efficient luminescent materials for future optoelectronic devices, including efficient and durable LSCs.

Keywords: luminescent materials, photochemistry, luminescent solar concentrators, β-diketonate-based europium complexes

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Authors: Ariungerel Jargal

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: Cave mining is a bulk underground mining method, which allows large low-grade deposits to be mined underground. This method involves undermining the orebody to make it collapse under its own weight into a series of chambers from which the ore extracted. It is a useful technique to extend the life of large deposits previously mined by open pits, and it is a method increasingly proposed for new mines around the world. We plan to conduct a feasibility study using Electrical impedance tomography (EIT) technology to show how much subsidence there is at the intersection with the cave mining surface. EIT is an imaging technique which uses electrical measurements at electrodes attached on the body surface to yield a cross-sectional image of conductivity changes within the object. EIT has been developed in several different applications areas as a simpler, cheaper alternative to many other imaging methods. A low frequency current is injected between pairs of electrodes while voltage measurements are collected at all other electrode pairs. In the difference EIT, images are reconstructed of the change in conductivity distribution (σ) between the acquisition of the two sets of measurements. Image reconstruction in EIT requires the solution of an ill-conditioned nonlinear inverse problem on noisy data, typically requiring make simpler assumptions or regularization. It is noted that the ratio of current to voltage represents a complex value according to Ohm’s law, and that it is theoretically possible to re-express EIT. The results of the experiment were presented on the simulation, and it was concluded that it is possible to conduct further real experiments. Drill a certain number of holes in the top wall of the cave to attach the electrodes, flow a current through them, and measure and acquire the potential through these electrodes. Appropriate values should be selected depending on the distance between the holes, the frequency and duration of the measurements, the surface characteristics and the size of the study area using an EIT device.

Keywords: impedance tomography, cave mining, soil, EIT device

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Authors: Shu-Yu Chung, Ying-Fang Wang, Shih-Min Wang

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To conduct long-term exposure assessments are important for workers exposed to chemicals with chronic effects. However, it usually encounters with several constrains, including cost, workers' willingness, and interference to work practice, etc., leading to inadequate long-term exposure data in the real world. In this study, an integrated approach was developed for conducting long-term exposure assessment for welding workers in a shipbuilding factory. A laboratory study was conducted to yield the fume generation rates under various operating conditions. The results and the measured environmental conditions were applied to the near field/far field (NF/FF) model for predicting long term fume exposures via the Monte Carlo simulation. Then, the predicted long-term concentrations were used to determine the prior distribution in Bayesian decision analysis (BDA). Finally, the resultant posterior distributions were used to assess the long-term exposure and serve as basis for initiating control strategies for shipbuilding workers. Results show that the NF/FF model was a suitable for predicting the exposures of metal contents containing in welding fume. The resultant posterior distributions could effectively assess the long-term exposures of shipbuilding welders. Welders' long-term Fe, Mn and Pb exposures were found with high possibilities to exceed the action level indicating preventive measures should be taken for reducing welders' exposures immediately. Though the resultant posterior distribution can only be regarded as the best solution based on the currently available predicting and monitoring data, the proposed integrated approach can be regarded as a possible solution for conducting long term exposure assessment in the field.

Keywords: Bayesian decision analysis, exposure assessment, near field and far field model, shipbuilding industry, welding fume

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Authors: Ayalkibet Mekonnen, Adane Abebe

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In hydrological cycle there are many water-related human interventions that modify the natural systems. Rainwater harvesting is one such intervention that involves harnessing of water in the upstream. Water harvesting used in upstream prevents water runoff on downstream mainly disturbance on biodiversity and ecosystems. The main objectives of the study are to assess the effects of water harvesting technologies on downstream water availability in the Woreda. To address the above problem, SWAT model, cost-benefit ratio and optimal control approach was used to analyse the hydrological and socioeconomic impact and tradeoffs on water availability of the community, respectively. The downstream impacts of increasing water consumption in the upstream rain-fed areas of the Bilate and Shala Catchment are simulated using the semi-distributed SWAT model. The two land use scenarios tested at sub basin levels (1) conventional land use represents the current land use practice (Agri-CON) and (2) in-field rainwater harvesting (IRWH), improving soil water availability through rainwater harvesting land use scenario. The simulated water balance results showed that the highest peak mean monthly direct flow obtained from Agri-CON land use (127.1 m3/ha), followed by Agri-IRWH land use (11.5 mm) and LULC 2005 (90.1 m3/ha). The Agri-IRWH scenario reduced direct flow by 10% compared to Agri-CON and more groundwater flow contributed by Agri-IRWH (190 m3/ha) than Agri-CON (125 m3/ha). The overall result suggests that the water yield of the Woreda may not be negatively affected by the Agri-IRWH land use scenario. The technology in the Woreda benefited positively having an average benefit cost ratio of 4.2. Water harvesting for domestic use was not optimal that the value of the water per demand harvested was less than the amount of water needed. Storage tanks, series of check dams, gravel filled dams are an alternative solutions for water harvesting.

Keywords: water harvesting, SWAT model, land use scenario, Agri-CON, Agri-IRWH, trade off, benefit cost ratio

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Authors: Grzegorz Szaciłowski, Marta Konop, Małgorzata Dymecka, Jakub Ośko

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In 1996, the European Council Directive 96/29/EURATOM pointed phosphate fertilizers to have a potentially negative influence on the environment from the radiation protection point of view. Fertilizers along with irrigation and crop rotation were the milestones that allowed to increase agricultural productivity. Firstly based on natural materials such as compost, manure, fish processing waste, etc., and since the 19th century created synthetically, fertilizers caused a boom in crop yield and helped to propel global food production, especially after World War II. In this work the concentrations of ²¹⁰Po, ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs in selected fertilizers and soil samples were determined. The results were used to calculate the annual addition of natural radionuclides and increment of the external radiation exposure caused by the use of studied fertilizers. Soils intended for different types of crops were sampled in early spring when no vegetation had occurred yet. Analysed fertilizers were those with which the soil was previously fertilized. For gamma radionuclides, a high purity germanium detector GX3520 from Canberra was used. The polonium concentration was determined by radiochemical separation followed by measurement by means of alpha spectrometry. The spectrometer used in this study was equipped with 450 cm² PIPS detector from Canberra. Obtained results showed significant differences in radionuclide composition between phosphate and nitrogenous fertilizers (e.g. the radium equivalent activity for phosphate fertilizer was 207.7 Bq/kg in comparison to <5.6 Bq/kg for nitrogenous fertilizer). The calculated increase of external radiation exposure due to use of phosphate fertilizer ranged between 3.4 and 5.4 nG/h, which represents up to 10% of the polish average outdoor exposure due to terrestrial gamma radiation (45 nGy/h).

Keywords: ²¹⁰Po, alpha spectrometry, exposure, gamma spectrometry, phosphate fertilizer, soil

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Authors: Todor Nickolov Stoyanov

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Cooperatives are present in all countries and in almost all sectors, including agriculture, forestry, food, finance, health, marketing, insurance and credit. Strong cooperatives are able to overcome many of the difficulties faced by private owners. Cooperatives use seven principles, including the 'Community Concern" principle, which enables cooperatives to work for the sustainable development of the community. The members of cooperatives may use different systems for generating year-round employment and for receiving sustainable income through performing different forestry activities. Various methods are used during the preparation of the report. These include literature reviews, statistics, secondary data and expert interviews. The members of the cooperatives are benefits exclusively from increasing the efficiency of the various products and from the overall yield of the harvest, and ultimately from achieving better profit through cooperative efforts. Cooperatives also use other types of activities that are an additional opportunity for cooperative income. There are many heterogeneous activities in the production and service sectors of the forest cooperatives under consideration. Some cooperatives serve dairies, distilleries, woodworking enterprises, tourist homes, hotels and motels, shops, ski slopes, sheep breeding, etc. Through the revenue generated by the activity, cooperatives have the opportunity to carry out various environmental and protective activities - recreation, water protection, protection of endangered and endemic species, etc., which in the case of small-scale forests cannot be achieved and the management is not sustainable. The conclusions indicate the results received in the analysis. Cooperative management of forests and forest lands gives higher incomes to individual owners. The management of forests and forest lands through cooperatives helps to carry out different environmental and protective activities. Cooperative forest management provides additional means of subsistence to the owners of poor forest lands. Cooperative management of forests and forest lands support owners to implement the forest management plans and to apply sustainable management of these territories.

Keywords: cooperative, forestry, forest owners, principles of cooperation

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Authors: Zhanara Suleimenova, Raushan Blieva, Aigerim Zhakipbekova, Inkar Tapenbayeva, Zhanar Narmuratova

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Green processes are based on innovative technologies that do not negatively affect the environment. Industrial enzymes originated from biological systems can effectively contribute to sustainable development through being isolated from microorganisms which are fermented using primarily renewable resources. Many widespread microorganisms secrete a significant amount of biocatalysts into the environment, which greatly facilitates the task of their isolation and purification. The ability to control the enzyme production through the regulation of their biosynthesis and the selection of nutrient media and cultivation conditions allows not only to increase the yield of enzymes but also to obtain enzymes with certain properties. In this regard, large potentialities are embedded in immobilized cells. Enzyme production technology in a secreted active form enabling industrial application on an economically feasible scale has been developed. This method is based on the immobilization of enzyme producers on a solid career. Immobilizing has a range of advantages: decreasing the price of the final product, absence of foreign substances, controlled process of enzyme-genesis, the ability of various enzymes' simultaneous production, etc. Design of proposed equipment gives the opportunity to increase the activity of immobilized cell culture filtrate comparing to free cells, growing in periodic culture conditions. Such technology allows giving a 10-times raise in culture productivity, to prolong the process of fungi cultivation and periods of active culture liquid generation. Also, it gives the way to improve the quality of filtrates (to make them more clear) and exclude time-consuming processes of recharging fermentative vials, that require manual removing of mycelium.

Keywords: industrial enzymes, immobilization, submerged fermentation, microscopic fungi

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Authors: María del Carmen Recio-Ruiz, Ramiro Ruiz-Rosas, Juana María Rosas, José Rodríguez-Mirasol, Tomás Cordero

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Nowadays, fossil resources are main precursors for fuel production. Due to their contribution to the greenhouse effect and their future depletion, there is a constant search for environmentally friendly feedstock alternatives. Biomass residues constitute an interesting replacement for fossil resources because of their zero net CO₂ emissions. One of the main routes to convert biomass into energy and chemicals is pyrolysis. In this work, conventional pyrolysis of different biomass residues highly available such as almond shells, hemp hurds, olive stones, and Kraft lignin, was studied. In a typical experiment, the biomass was crushed and loaded into a fixed bed reactor under continuous nitrogen flow. The influence of temperature (400-800 ºC) and heating rate (10 and 20 ºC/min) on the pyrolysis yield and composition of the different fractions has been studied. In every case, the mass yields revealed that the solid fraction decreased with temperature, while liquid and gas fractions increased due to depolymerization and cracking reactions at high temperatures. The composition of every pyrolysis fraction was studied in detail. The results showed that the composition of the gas fraction was mainly CO, CO₂ when working at low temperatures, and mostly CH₄ and H₂at high temperatures. The solid fraction developed an incipient microporosity, with narrow micropore volume of 0.21 cm³/g. Regarding the liquid fraction, pyrolysis of almond shell, hemp hurds, and olive stones led mainly to a high content in aliphatic acids and furans, due to the high volatile matter content of these biomass (>74 %wt.), and phenols to a lesser degree, which were formed due to the degradation of lignin at higher temperatures. However, when Kraft lignin was used as bio-oil precursor, the presence of phenols was very prominent, and aliphatic compounds were also detected in a lesser extent.

Keywords: Bio-oil, biomass, conventional pyrolysis, lignocellulosic

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Authors: Kayode Fatokun, Nozipho N. Motsa

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Field experiments were carried out during the summer/autumn (first trial) and winter/spring (second trial) seasons of 2019 and 2021 inDlangubo, Ngwelezane, and Mtubatubaareas of KwaZulu-Natal Province of South Africa to study the drought amelioration effects and impact of 2 locally available organic wastes [filter cake (FC) and macadamia husk compost (MHC)] on the productivity, and physiological responses of 4 orange-fleshed sweet potato cultivars (Buregard cv., Impilo, W-119 and 199062.1). The effects of FC and MHC were compared with that of inorganic fertilizer (IF) [2:3:2 (30)], FC+IF, MHC+IF, and control. The soil amendments were applied in the first trials only. Climatic data such as humidity, temperature, and rainfall were taken via remote sensing. The results of the first trial indicated that filter cake and IF significantly performed better than MHC. While the strength of filter cake may be attributable to its rich array of mineral nutrients such as calcium, magnesium, potassium, sodium, zinc, copper, manganese, iron, and phosphorus. The little performance from MHC may be attributable to its water holding capacity. Also, a positive correction occurred between the yield of the test OFSP cultivars and climatic factors such as rainfall, NDVI, and NDWI values. Whereas the inorganic fertilizer did not have any significant effect on the growth and productivity of any of the tested sweet potato cultivars in the second trial; FC, and MHC largely maintained their significant performances. In conclusion, the use of FC is highly recommended in the production of the test orange-fleshed sweet potato cultivars. Also, the study indicated that both FC and MHC may not only supply the needed plant nutrients but has the capacity to reduce the impact of drought on the growth of the test cultivars. These findings are of great value to farmers, especially the resource-poorones.

Keywords: amendments, drought, filter cake, macadamia husk compost, sweet potato

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Authors: Nahia H. Sassine, Frédéric-Victor Donzé, Arnaud Bruch, Barthélemy Harthong

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Thermal Energy Storage (TES) systems are central elements of various types of power plants operated using renewable energy sources. Packed bed TES can be considered as a cost–effective solution in concentrated solar power plants (CSP). Such a device is made up of a tank filled with a granular bed through which heat-transfer fluid circulates. However, in such devices, the tank might be subjected to catastrophic failure induced by a mechanical phenomenon known as thermal ratcheting. Thermal stresses are accumulated during cycles of loading and unloading until the failure happens. For instance, when rocks are used as storage material, the tank wall expands more than the solid medium during charge process, a gap is created between the rocks and tank walls and the filler material settles down to fill it. During discharge, the tank contracts against the bed, resulting in thermal stresses that may exceed the wall tank yield stress and generate plastic deformation. This phenomenon is repeated over the cycles and the tank will be slowly ratcheted outward until it fails. This paper aims at studying the evolution of tank wall stresses over granular bed thermal cycles, taking into account both thermal and mechanical loads, with a numerical model based on the discrete element method (DEM). Simulations were performed to study two different thermal configurations: (i) the tank is heated homogeneously along its height or (ii) with a vertical gradient of temperature. Then, the resulting loading stresses applied on the tank are compared as well the response of the internal granular material. Besides the study of the influence of different thermal configurations on the storage tank response, other parameters are varied, such as the internal angle of friction of the granular material, the dispersion of particles diameters as well as the tank’s dimensions. Then, their influences on the kinematics of the granular bed submitted to thermal cycles are highlighted.

Keywords: discrete element method (DEM), thermal cycles, thermal energy storage, thermocline

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Authors: Chinwe Juliana Abara, Dayo Keshi

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Through cultural heritage materials, nations witness significant boom in the world of art and tourism as well as attract foreign investors and tourists to the benefit of the regions and countries where they are located. There are notable heritage sites which record visits by tourists in their thousands annually. According to UNESCO the cultural heritage reflects the life of the community, its history and its identity. Its preservation helps to rebuild broken communities, re-establish their identities, and link their past with their present and future. During any form of conflict or war, a lot happen. People die, houses destroyed and every other thing in the society suffers. Wars and conflicts in various countries have claimed antiquities, heritage materials, contemporary Arts, Galleries, Museums, Archives and very important Monuments and Heritage sites. My Paper deals with the effects of insurgencies and conflicts on cultural heritage and tourism industries in Nigeria and how they can be protected and restored so as to yield the desirable economic gains. Preceding from the premise that conflict of any type puts our cultural heritage at risk; this paper also explores the practical challenges and opportunities available to us in the face of incessant ethnic and Boko Haram (western education is abomination) insurgents and their wanton destruction of lives and properties. There will be a review of relevant literature and documents on the effects of violence on heritage materials and tourism industries in Nigeria particularly and other parts of the world in generally .My paper also highlights the activities the National Council for Arts and Culture as well as other Cultural Agencies in Nigeria have employed to sensitize the stakeholders, the youth, the elderly, and the community at large on the need for peaceful co-existence so as to collectively strive to safeguard and secure our cultural heritage in the face of all these challenges for posterity and desirable economic gains.

Keywords: cultural heritage, conflict, tourism, insurgency, challenges

Procedia PDF Downloads 367

Authors: Roopchand Tandon, Zaheer Khan Yusufzai, R. Manna, R. K. Mandal

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Present work describes microstructures, mechanical properties, and texture characteristics of the friction stir processed AA7075T7352 aluminum alloy. Phases were analyzed with the help of x-ray diffractometre (XRD), transmission electron microscope (TEM) along with the differential scanning calorimeter (DSC). Depth-wise microstructures and dislocation characteristics from the nugget-zone of the friction stir processed specimens were studied using the bright field (BF) and weak beam dark-field (WBDF) TEM micrographs, and variation in the microstructures as well as dislocation characteristics were the noteworthy features found. XRD analysis display changes in the chemistry as well as size of the phases in the nugget and heat affected zones (Nugget and HAZ). Whereas the base metal (BM) microstructures remain un-affected. High density dislocations were noticed in the nugget regions of the processed specimen, along with the formation of dislocation contours and tangles. .The ɳ’ and ɳ phases, along with the GP-Zones were completely dissolved and trapped by the dislocations. Such an observations got corroborated to the improved mechanical as well as stress corrosion cracking (SCC) performances. Bulk texture and residual stress measurements were done by the Panalytical Empyrean MRD system with Co- kα radiation. Nugget zone (NZ) display compressive residual stress as compared to thermo-mechanically(TM) and heat affected zones (HAZ). Typical f.c.c. deformation texture components (e.g. Copper, Brass, and Goss) were seen. Such a phenomenon is attributed to the enhanced hardening as well as other mechanical performance of the alloy. Mechanical characterizations were done using the tensile test and Anton Paar Instrumented Micro Hardness tester. Enhancement in the yield strength value is reported from the 89MPa to the 170MPa; on the other hand, highest hardness value was reported in the nugget-zone of the processed specimens.

Keywords: aluminum alloy, mechanical characterization, texture characterstics, friction stir processing

Procedia PDF Downloads 71

Authors: S. Mamoucha, N. Tsafantakis, Α. Ioannidis, S. Chatzipanagiotou, C. Nikolaou, L. Skaltsounis, N. Fokialakis, N. Christodoulakis

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Introduction: Plant secondary metabolites (SM) can be grouped into three chemically distinct groups: terpenes, phenolics, and nitrogen-containing compounds. For many years the adaptive significance of SM was unknown. They were thought to be functionless end-products. Currently it is accepted that many secondary metabolites (also known as natural products) have important ecological roles in plants. For instance, they serve as attractants (odor, color, taste) for pollinators and seed-dispersing animals. Moreover, they protect plants from herbivores, microbial pathogens and from environmental stress (high and low temperatures, drought, alkalinity, salinity, radiation etc). It is well known that both biotic and abiotic stress often increase the accumulation of SM. The local climatic conditions, seasonal changes, external factors such as light, temperature, humidity affect the biosynthesis and composition of secondary metabolites. A well known dioecious evergreen plant, Pistacia lentiscus L. (mastic tree), was selected in order to study the metabolic variations occur in response to the different climate conditions, due to the seasonal variation and its effect on the biosynthesis of bioactive compounds. Materials-methods: Young and mature leaves were collected in January and July 2014, dried and extracted by accelerated solvent extraction (Dionex ASE™ 350) using solvents of increased polarity (DCM, MeOH, and H2O). GC-MS and UHPLC-HRMS analysis were carried out in order to define the nature and the relative abundance of SM. The antibacterial activity was evaluated by using the Agar Disc Diffusion Assay against ATCC and clinical isolates strains: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Streptococcus mutans and Klebsiella pneumoniae. All tests were carried out in duplicate and the average radii of the inhibition zones were calculated for each extract. Results: According to the phytochemical profile obtained from each extract, the biosynthesis of SM varied both qualitatively and quantitatively under the two different types of seasonal stress. With exception of the biologically inactive nonpolar DCM extract of July, all extracts inhibited the growth of most of the investigated microorganisms. A clear positive correlation has been observed between the relative abundance of SM and the bioactivity of the DCM extracts of January and July. Observed changes during phytochemical analysis were mainly focused on the triterpenoid content. On the other hand, the bioactivity of the polar extracts (MeOH and H2O) of January and July resulted practically invariable against most of the microorganisms, besides the significant variation of the SM content due to the seasonal variation. Conclusion: Our results clearly confirmed the hypothesis of abiotic stress as an important regulating factor that significantly affects the biosynthesis of secondary metabolites and thus the presence of bioactive compounds. Acknowledgment: This work was supported by IKY - State Scholarship Foundation, Athens, Greece.

Keywords: antibacterial screening, phytochemical profile, Pistacia lentiscus, abiotic stress

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Authors: Francesca Radice

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Domestic and sexual violence provokes, on average in Australia, one female death per week due to intimate violence behaviours. 83% of couples meet online, and intercepting domestic and sexual violence at this level would be beneficial. It has been observed that violent or coercive behaviour has been apparent from initial conversations on dating apps like Tinder. Child pornography, stalking, and coercive control are some criminal offences from dating apps, including women murdered after finding partners through Tinder. Police databases and predictive policing are novel approaches taken to prevent crime before harm is done. This research will investigate how police databases can be used in a privacy-preserving way to characterise users in terms of their potential for violent crime. Using the COPS database of NSW Police, we will explore how the past criminal record can be interpreted to yield a category of potential danger for each dating app user. It is up to the judgement of each subscriber on what degree of the potential danger they are prepared to enter into. Sentiment analysis is an area where research into natural language processing has made great progress over the last decade. This research will investigate how sentiment analysis can be used to interpret interchanges between dating app users to detect manipulative or coercive sentiments. These can be used to alert law enforcement if continued for a defined number of communications. One of the potential problems of this approach is the potential prejudice a categorisation can cause. Another drawback is the possibility of misinterpreting communications and involving law enforcement without reason. The approach will be thoroughly tested with cross-checks by human readers who verify both the level of danger predicted by the interpretation of the criminal record and the sentiment detected from personal messages. Even if only a few violent crimes can be prevented, the approach will have a tangible value for real people.

Keywords: sentiment analysis, data mining, predictive policing, virtual manipulation

Procedia PDF Downloads 53

Authors: Dwi Arisandi Wijaya, Ernawati Arifin Giri-Rachman, Neni Nurainy

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Typhoid fever disease can be prevented by using a polysaccharide-based vaccine Vi which is a virulence factor of S.typhi. To produce high yield Vi polysaccharide from bacteria, it is important to know the biosynthesis of Vi polysaccharide and the regulators involved. In the In vivo condition, S. typhi faces different osmolarity, and the bacterial two-component system OmpR-EnvZ, regulate by up and down Capsular Vi polysaccharide biosynthesis. A high yielded Vi Polysaccharide strain, S. typhi strain C6524 used to study the effect of media osmolarity on Vi polysaccharide biosynthesis and the osmoregulation pattern of S. typhi strain C6524. The methods were performed by grown S. typhi strain C6524 grown on medium with 50 mM, 100 mM, and 150 mM osmolarity with the batch system. Vi polysaccharide concentration was measured by ELISA method. For further investigation of the osmoregulation pattern of strain C6524, the osmoregulator gene, OmpR, has been isolated and sequenced using the specific primer of the OmpR gene. Nucleotide sequence analysis is done with BLAST and Lallign. Amino Acid sequence analysis is done with Prosite and Multiple Sequence Alignment. The results of cultivation showed the average content of polysaccharide Vi for 50 mM, 100 mM, and 150 mM osmolarities 11.49 μg/mL, 12.06 μg/mL, and 14.53 μg/mL respectively. Analysis using Anova stated that the osmolarity treatment of 150 mM significantly affects Vi content. Analysis of nucleotide sequences shows 100% identity between S. typhi strain C6524 and Ty2. Analysis of amino acid sequences shows that the OmpR response regulator protein of the C6524 strain also has a α4-β5-α5 motif which is important for the regulatory activation system when phosphorylation occurs by domain kinase. This indicates that the regulator osmolarity response of S. typhi strain C6524 has no difference with the response regulator owned by S. typhi strain Ty2. A high Vi response rate in the 150 mM osmolarity treatment requires further research for RcsB-RcsC, another two-component system involved in Vi Biosynthesis.

Keywords: osmoregulator, OmpR, Salmonella, Vi polysaccharide

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Authors: Velasco-Rendón María Del Carmen, Cuéllar-Bermúdez Sara Paulina, Parra-Saldívar Roberto

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Phycocyanin is a blue pigment protein with fluorescent activity produced by cyanobacteria. It has been recently studied to determine its anticancer, antioxidant and antiinflamatory potential. Since 2014 it was approved as a Generally Recognized As Safe (GRAS) proteic pigment for the food industry. Therefore, phycocyanin shows potential for the food, nutraceutical, pharmaceutical and diagnostics industry. Conventional phycocyanin extraction includes buffer solutions and ammonium sulphate followed by chromatography or ATPS for protein separation. Therefore, further purification steps are time-requiring, energy intensive and not suitable for scale-up processing. This work presents an alternative to conventional methods that also allows large scale application with commercially available equipment. The extraction was performed by exposing the dry biomass to mechanical cavitation and salting out with NaCl to use an edible reagent. Also, isoelectric point precipitation was used by addition of HCl and neutralization with NaOH. The results were measured and compared in phycocyanin concentration, purity and extraction yield. Results showed that the best extraction condition was the extraction by salting out with 0.20 M NaCl after 30 minutes cavitation, with a concentration in the supernatant of 2.22 mg/ml, a purity of 3.28 and recovery from crude extract of 81.27%. Mechanical cavitation presumably increased the solvent-biomass contact, making the crude extract visibly dark blue after centrifugation. Compared to other systems, our process has less purification steps, similar concentrations in the phycocyanin-rich fraction and higher purity. The contaminants present in our process edible NaCl or low pHs that can be neutralized. It also can be adapted to a semi-continuous process with commercially available equipment. This characteristics make this process an appealing alternative for phycocyanin extraction as a pigment for the food industry.

Keywords: extraction, phycocyanin, precipitation, scale-up

Procedia PDF Downloads 409