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Number of results: 6
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Abstract

Soybean [Glycine max (L.)], one of the most important crops in Argentina, is commonly infected by Colletotrichum truncatum, the causal agent of anthracnose. Tagetes filifolia essential oil (EO) is presented as a natural approach to minimize the dose of chemical fungicides applied to the crop. The fungus Trichoderma harzianum is used as a biocontrol agent because of its ability to produce secondary metabolites that destroy cell walls of phytopathogenic fungi. However, its performance can be affected when it is exposed to chemical fungicides. The objective of this work was to evaluate the antifungal activity of T. filifolia EO both individually and combined with chemical fungicides against C. truncatum, and its effect on T. harzianum. Fungi were isolated from soybean crops. The following pesticides were assessed: carbendazim (F1), difenoconazole (F2) and trifloxystrobin + cyproconazole (F3). The EO was obtained from native plants and its chemical composition was analyzed by gas chromatography–mass spectrometry (GC–MS). The minimum fungicide concentration (MFC) was determined for each compound. Fungicides were combined with the EO to look for combinations that allowed a reduction of pesticide doses. Among fungicides, F1 showed the strongest antifungal activity against C. truncatum (MFC = 0.25 μl ⋅ l–1) and T. harzianum (MFC = 1.5 μl ⋅ l–1). The sensitivity of both fungi to the EO was lower than to fungicides. The EO presented MFCs of 6,000 and 9,000 μl ⋅ l–1 against C. truncatum and T. harzianum. The EO and F1 affected the growth of T. harzianum at concentrations that controlled C. truncatum (31 and 10%). Eight combinations of fungicides and the EO allowed fungicide concentration reductions of up to 80%, although the growth of the biocontrol strain was also affected. The results demonstrated that T. filifolia EO can be used to control anthracnose and reduce doses of chemical fungicides applied to soybean crops. Its effect on T. harzianum should be considered in the design of integrated pest management strategies.

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Authors and Affiliations

Laura Carolina Gadban
Boris Xavier Camiletti
Ezequiel Darío Bigatton
Silvia Graciela Distéfano
Enrique Iván Lucini Lucini
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Abstract

Annual losses of cocoa in Ghana to insect pests are significant. The use of integrated pest management (IPM) tools is critical for effective pest management. Previous studies on the subject have considered how farmers perceive the economic impact of insect pests on cocoa. These studies however did not investigate farmers’ ability to identify pests, associated damage symptoms and their implications for pest management. The current study, therefore, assessed farmers’ ability to correctly associate insect damage with the pest species that caused it. A total of 600 farmers were interviewed in the Eastern, Ashanti, Western, Brong Ahafo and Central Regions of Ghana with a structured open and closedended questionnaire. Most farmers (>85%) were unable to correctly identify and associate pests to their damage. The majority (>80%) of farmers also could not link the immature stages of insect pests to their adult stages. Wrong identification of the major pests (>85%) led to a wide variation in the timing of insecticide application amongst farmers. The majority of the farmers (60%) interviewed had not received training in insect pest identification. The study shows that 90% of the farmers, who had received some training, got it from the Cocoa Health and Extension Division (CHED) of the Ghana Cocoa Board (COCOBOD). Almost all respondents (98%) agreed that correct pest identification is critical for effective pest control. The importance of pest identification and monitoring as a component of IPM is discussed.
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Authors and Affiliations

Godfred Kweku Awudzi
1
Richard Adu-Acheampong
1
Silas Wintuma Avicor
1
Yahaya Bukari
2
Millicent Adomaa Yeboah
3
Edmond Kwadwo Oti Boateng
4
Stephen Kwame Ahadzi
1

  1. Entomology, Cocoa Research Institute of Ghana (CRIG), Ghana
  2. Plant Pathology, Cocoa Research Institute of Ghana (CRIG), Ghana
  3. Extension, Cocoa Health and Extension Division (CHED), Ghana
  4. Social Science and Statistics Unit (SSU), Cocoa Research Institute of Ghana (CRIG), Ghana
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Abstract

Development and demography of Adalia decempunctata L. were studied under laboratory conditions at seven constant temperatures (12, 16, 20, 24, 28, 32 and 36°C). First instar larvae failed to develop to second instar at 12°С and no development occurred at 36°C. The total developmental time varied from 47.92 days at 16°C to 15.94 days at 28°C and increased at 32°C. The lower temperature thresholds of 11.05 and 9.90°C, and thermal constants of 290.84 day-degree and 326.34 day-degree were estimated by traditional and Ikemoto-Takai linear models, respectively. The lower temperature threshold (Tmin) values estimated by Analytis, Briere-1, Briere-2 and Lactin-2 for total immature stages were 11.99, 12.24, 10.30 and 10.8°C, respectively. The estimated fastest developmental temperatures (Tfast) by the Analytis, Briere-1, Briere-2 and Lactin-2 for overall immature stages development of A. decempunctata were 31.5, 31.1, 30.7 and 31.7°C, respectively. Analytis, Briere-1, Briere-2 and Lactin-2 measured the upper temperature threshold (Tmax) at 33.14, 36.65, 32.75 and 32.61°C. The age-stage specific survival rate (sxj) curves clearly depicted the highest and lowest survival rates at 16 and 32°C for males and females. The age-specific fecundity (mx) curves revealed higher fecundity rate when fed A. gossypii at 24 and 28°C. The highest and lowest values of intrinsic rate of increase (r) were observed at 28 and 16°C (0.1945 d–1 and 0.0592 d–1, respectively). Also, the trend of changes in the finite rate of increase (λ) was analogous with intrinsic rate of increase. The longest and shortest mean generation time (T) was observed at 16 and 28°C, respectively and the highest net reproductive rates (R0) was estimated at 24 and 28°C. According to the results, the most suitable temperature seems to be 28°C due to the shortest developmental time, highest survival rate, and highest intrinsic rate of increase.

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Authors and Affiliations

Zahra Mojib-Haghghadam
Jalal Jalali Sendi
Arash Zibaee
Jafar Mohaghegh
Azadeh Karimi-Malati
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Abstract

The Integrated Psychosocial Model of Criminal Social Identity (IPM-CSI) explains the underlying reasons, i.e. risk factors, for the development of criminal social identity (CSI). Empirical research surrounding these risk factors is inconsistent in the measures and procedures used and the risk factors were mostly considered in isolation from one another. The main purpose of the paper was to review existing empirical studies elucidating correlates of CSI incorporated in the IPM-CSI and indicate further direction for research. A search in PubMed, PsychInfo, ERIC, Google Scholar, and the journal Child Development and Adolescent Studies was performed. Eleven studies exploring the correlates of CSI were identified and discussed herein. Studies indicated that there is potential for further expansion of the IPM-CSI to consider the consequences of CSI. Based on the present study results, a set of recommendations are provided for future research.

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Authors and Affiliations

Alisa Victoria Spink
Russell Woodfield
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Abstract

This paper presents the resolution of the optimal reactive power dispatch (ORPD) problem and the control of voltages in an electrical energy system by using a hybrid algorithm based on the particle swarmoptimization (PSO) method and interior point method (IPM). The IPM is based on the logarithmic barrier (LB-IPM) technique while respecting the non-linear equality and inequality constraints. The particle swarmoptimization-logarithmic barrier-interior point method (PSO-LB-IPM) is used to adjust the control variables, namely the reactive powers, the generator voltages and the load controllers of the transformers, in order to ensure convergence towards a better solution with the probability of reaching the global optimum. The proposed method was first tested and validated on a two-variable mathematical function using MATLAB as a calculation and execution tool, and then it is applied to the ORPD problem to minimize the total active losses in an electrical energy network. To validate the method a testwas carried out on the IEEE electrical energy network of 57 buses.

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Authors and Affiliations

Aissa Benchabira
Mounir Khiat
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Abstract

This paper presents a review of the electromagnetic field and a performance analysis of a radial flux interior permanent magnet (IPM) machine designed to achieve 80 kW and 125 Nmfor an electric and hybrid traction vehicle. The motor consists of a 12-slot stator with a three-phase concentrated winding as well as an 8-pole rotor with V-shaped magnets. Selected motor parameters obtained from an IPM prototype were compared with the design requirements. Based on the electromagnetic field analysis, the authors have indicated the parts of the motor that should be redesigned, including the structure of the rotor core, aimed at enhancing the motor’s performance and adjusting segmentation for magnet eddy current loss reduction. In addition, iron and PM eddy current losses were investigated. Moreover, transient analysis of current peak value showed that the current may increase significantly compared to steady-state values.Amap of transient peak current load vs. torque load plotted against rotor speed was provided. Based on the numeric and analytical results of physical machine parameters, the authors indicate that collapse load during the motor’s operation may significantly increase the risk of permanent magnet (PM) demagnetization. It was also found that collapse load increases the transient torque, which may reduce the lifetime of windings.

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Authors and Affiliations

Adrian Młot
ORCID: ORCID
Marcin Kowol
Janusz Kołodziej
Andrzej Lechowicz
Piotr Skrobotowicz

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