13 research outputs found

    The Impact of Different Cultivation Practices on Surface Runoff, Soil and Nutrient Losses in a Rotational System of Legume–Cereal and Sunflower

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    Soil erosion is among the biggest problems in the agricultural sector that can affect ecosystems and human societies. A field of 5° slope was selected to study the runoff, soil and nutrient loss as well as crop productivity in different treatments—conventional tillage (CT) vs. no-tillage (NT), plant vs. no plant cover, contour cultivation (CC) vs. perpendicular to the contour cultivation, (PC) under natural rainfall. The experiment was conducted in central Greece in two cultivation periods. In autumn, the field was cultivated with intercropping Triticosecale and Pisum sativum and in spring with sunflower. The total rainfall was 141.4 mm in the 1st year and 311 mm in the 2nd. We found that runoff in the treatment of no tillage with contour cultivation was 85% lower in both years compared to the no tillage-no plant control. Therefore, the contour cultivation-no tillage treatment had a positive effect by decreasing phosphorus and potassium loss from soil: indeed, there was a decrease in P and K by 55% and 62%, respectively, in the NT compared to the CC treatments. We conclude that the NT-CC treatment with plant cover was the most effective in reducing water runoff and soil nutrient loss and increasing yield

    The Impact of Different Cultivation Practices on Surface Runoff, Soil and Nutrient Losses in a Rotational System of Legume–Cereal and Sunflower

    No full text
    Soil erosion is among the biggest problems in the agricultural sector that can affect ecosystems and human societies. A field of 5° slope was selected to study the runoff, soil and nutrient loss as well as crop productivity in different treatments—conventional tillage (CT) vs. no-tillage (NT), plant vs. no plant cover, contour cultivation (CC) vs. perpendicular to the contour cultivation, (PC) under natural rainfall. The experiment was conducted in central Greece in two cultivation periods. In autumn, the field was cultivated with intercropping Triticosecale and Pisum sativum and in spring with sunflower. The total rainfall was 141.4 mm in the 1st year and 311 mm in the 2nd. We found that runoff in the treatment of no tillage with contour cultivation was 85% lower in both years compared to the no tillage-no plant control. Therefore, the contour cultivation-no tillage treatment had a positive effect by decreasing phosphorus and potassium loss from soil: indeed, there was a decrease in P and K by 55% and 62%, respectively, in the NT compared to the CC treatments. We conclude that the NT-CC treatment with plant cover was the most effective in reducing water runoff and soil nutrient loss and increasing yield

    Design and implementation of a hybrid model based on two-layer decomposition method coupled with extreme learning machines to support real-time environmental monitoring of water quality parameters

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    Accurate prediction of water quality parameters plays a crucial and decisive role in environmental monitoring, ecological systems sustainability, human health, aquaculture and improved agricultural practices. In this study a new hybrid two-layer decomposition model based on the complete ensemble empirical mode decomposition algorithm with adaptive noise (CEEMDAN) and the variational mode decomposition (VMD) algorithm coupled with extreme learning machines (ELM) and also least square support vector machine (LSSVM) was designed to support real-time environmental monitoring of water quality parameters, i.e. chlorophyll-a (Chl-a) and dissolved oxygen (DO) in a Lake reservoir. Daily measurements of Chl-a and DO for June 2012–May 2013 were employed where the partial autocorrelation function was applied to screen the relevant inputs for the model construction. The variables were then split into training, validation and testing subsets where the first stage of the model testing captured the superiority of the ELM over the LSSVM algorithm. To improve these standalone predictive models, a second stage implemented a two-layer decomposition with the model inputs decomposed in the form of high and low frequency oscillations, represented by the intrinsic mode function (IMF) through the CEEMDAN algorithm. The highest frequency component, IMF1 was further decomposed with the VMD algorithm to segregate key model input features, leading to a two-layer hybrid VMD-CEEMDAN model. The VMD-CEEMDAN-ELM model was able to reduce the root mean square and the mean absolute error by about 14.04% and 7.12% for the Chl-a estimation and about 5.33% and 4.30% for the DO estimation, respectively, compared with the standalone counterparts. Overall, the developed methodology demonstrates the robustness of the two-phase VMD-CEEMDAN-ELM model in identifying and analyzing critical water quality parameters with a limited set of model construction data over daily horizons, and thus, to actively support environmental monitoring tasks, especially in case of high-frequency, and relatively complex, real-time datasets

    Predictive factors of the exceptionally high number of industrial accidents at work in Greece: A statistical analysis of Sample Survey Results

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    The strong commitment of the management of a company to the maintenance of a safe work environment is an important stimulus for its workers to be loyal to the company and to make every effort to keep the company profitable.In this paper we investigate by a sample survey in a sample of 763 workers who work in heavy industries in Greece the factors which contribute to the occurrence of accidence at work. An exploratory factor analysis ,Reliability Analysis and Multinomial Logistic Regression revealed the following factors which increase the frequency of occurrence of accidents at work: 2 Exposure of the workers to physical or technical dangerous conditions at work, lack of inspections by the Government’s Safety Inspectors , lack of training programs designed by the company in order to protect the workers from harmful machinery and to show to them the proper use of tools, lack of proper maintenance of machinery and negligence in the part of the company in following the recommendations of safety inspectors. Cronbach”s Alpha for the variables of the questionnaire referring to the factors contributing to the occurrence of accidents is 0,81.A Multinomial Logistic Regression with dependent variable the question: did you have in the past an accident at work ,was carried out and revealed that the independent variables: lack of inspection of the machinery of the company, lack of proper training procedures for the workers of the company, inadequate work experience of the workers, lack of proper supervision and nature of work ,were statistically significant.The sample survey was carried out in January of 2013 and it shows that the Safety Inspectors, which were public employees, should make every effort to keep, with their efficient inspection visits, the industrial base of this country functioning properly in order to decrease the unemployment level in times of deep financial , social and political crisis in Greece

    Speak with signs: Active learning platform for Greek Sign Language, English Sign Language, and their translation

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    Sign Language is used to facilitate the communication between Deaf and non-Deaf people. It uses signs-words with basic structural elements such as handshape, parts of face, body or space, and the orientation of the fingers-palm. Sign Languages vary from people to people and from country to country and evolve as spoken languages. In the current study, an application which aims at Greek Sign Language and English Sign Language learning by hard of hearing people and talking people, has been developed. The application includes grouped signs in alphabetical order. The user can find Greek Sign Language signs, English sign language signs and translate from Greek sign language to English sign language. The written word of each sign, and the corresponding meaning are displayed. In addition, the sound is activated in order to enable users with partial hearing loss to hear the pronunciation of each word. The user is also provided with various tasks in order to enable an interaction of the knowledge acquired by the user. This interaction is offered mainly by multiple-choice tasks, incorporating text or video. The current application is not a simple sign language dictionary as it provides the interactive participation of users. It is a platform for Greek and English sign language active learning

    Psychometric validation of two versions of the adolescent Depression Self-Rating Scale (DSRS-A and DSRS-A Screener).

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    AIM: Examination of psychometric properties and diagnostic accuracy of the Depression Self-Rating Scale for Adolescents (DSRS-A) as well as development and evaluations of a shorter version, DSRS-A-Screener. METHODS: Analyses of component structure and internal consistency were performed in a community-based sample of adolescents N = 4,506 and among consecutive outpatients from three child psychiatric settings in Sweden (n = 137). Concurrent validity was measured as a correlation between a summation index of the scale items and the total major depressive disorder (MDD) symptom severity score from the Kiddie Schedule of Affective Disorders and Schizophrenia (K-SADS). Diagnostic accuracy was examined in the clinical sample, with the K-SADS interview as the reference test, by receiver operating characteristic analysis (ROC), calculations of sensitivity, specificity among other measures. With the purpose to select items for a shorter scale, associations between scale items and MDD were examined with binary logistic regression. This shorter scale was thereafter examined similarly. RESULTS: Based on association with MDD, five items were selected for the brief DSRS-A Screener that showed one component structure, internal consistency Cronbach's alpha .80 and.82, respectively. In the clinical population concurrent validity was Spearman's rho .63 and ROC analysis showed AUC .84 (95% CI .78-.91; p < .001). The optimal cut-off for screening was 2 with sensitivity .85 and specificity of .64. CONCLUSION: The DSRS-A Screener compared to the original scale, maintained or improved reliability, validity, and showed moderate diagnostic accuracy

    Estimating remobilization of potentially toxic elements in soil and road dust of an industrialized urban environment

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    The mobility of potentially toxic elements (PTEs) is of paramount concern in urban settings, particularly those affected by industrial activities. Here, contaminated soils and road dusts of the medium-size, industrialized city of Volos, Central Greece, were subjected to single-step extractions (0.43 M HNO3 and 0.5 M HCl) and the modified BCR sequential extraction procedure. This approach will allow for a better understanding of the geochemical phase partitioning of PTEs and associated risks in urban environmental matrices. Based on single extraction procedures, Pb and Zn exhibited the highest remobilization potential. Of the non-residual phases, the reducible was the most important for Pb, and the oxidizable for Cu and Zn in both media. On the other hand, mobility of Ni, Cr, and Fe was low, as inferred by their dominance into the residual fraction. Interestingly, we found a significant increase of the residual fraction in the road dust samples compared to soils. Carbonate content and organic matter controlled the extractabilities of PTEs in the soil samples. By contrast, for the road dust, magnetic susceptibility exerted the main control on the geochemical partitioning of PTEs. We suggest that anthropogenic particles emitted by heavy industries reside in the residual fraction of the SEP, raising concerns about the assessment of this fraction in terms of origin of PTEs and potential environmental risks. Conclusively, the application of sequential extraction procedures should be complemented with source identification of PTEs with the aim to better estimate the remobilization of PHEs in soil and road dust influenced by industrial emissions

    Major and trace element contents in apples from a cultivated area of central Greece

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    Forty-two soil and apple samples from central Greece were collected and analyzed with regards to the content in major (Ca, Fe, K, Mg, Na, P, and S) and trace elements (As, B, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sr, Ti, and Zn). Soil samples were analyzed by inductively coupled plasma atomic emission spectrometry, while for the apples inductively coupled plasma mass spectrometry was implemented. Several elements such as As, B, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, Ti, and Zn, represent high concentrations in apples from the study area. These relatively high concentrations may be a consequence of the local geology, along with the excessive application of agricultural products such as fertilizers and agrochemicals
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