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Sample records for halotydeus destructor tucker

  1. Challenges in devising economic spray thresholds for a major pest of Australian canola, the redlegged earth mite (Halotydeus destructor).

    Science.gov (United States)

    Arthur, Aston L; Hoffmann, Ary A; Umina, Paul A

    2015-10-01

    A key component for spray decision-making in IPM programmes is the establishment of economic injury levels (EILs) and economic thresholds (ETs). We aimed to establish an EIL for the redlegged earth mite (Halotydeus destructor Tucker) on canola. Complex interactions between mite numbers, feeding damage and plant recovery were found, highlighting the challenges in linking H. destructor numbers to yield. A guide of 10 mites plant(-1) was established at the first-true-leaf stage; however, simple relationships were not evident at other crop development stages, making it difficult to establish reliable EILs based on mite number. Yield was, however, strongly associated with plant damage and plant densities, reflecting the impact of mite feeding damage and indicating a plant-based alternative for establishing thresholds for H. destructor. Drawing on data from multiple field trials, we show that plant densities below 30-40 plants m(-2) could be used as a proxy for mite damage when reliable estimates of mite densities are not possible. This plant-based threshold provides a practical tool that avoids the difficulties of accurately estimating mite densities. The approach may be applicable to other situations where production conditions are unpredictable and interactions between pests and plant hosts are complex. © 2015 Society of Chemical Industry.

  2. Pyrethroid resistance discovered in a major agricultural pest in southern Australia: the redlegged earth mite Halotydeus destructor (Acari: Penthaleidae).

    Science.gov (United States)

    Umina, Paul A

    2007-12-01

    The redlegged earth mite (Halotydeus destructor Tucker) is an important pest of field crops and pastures. Control of this pest relies heavily on chemicals, with few genuine alternatives presently available. Pesticide responses of H. destructor from the field with reported chemical control failures were compared with mites from susceptible 'control' populations. Toxicology bioassays were conducted on adult mites across multiple generations. Very high levels of resistance to two synthetic pyrethroids, bifenthrin and alpha-cypermethrin, were detected in this species for the first time. For bifenthrin, LC(50) estimates showed a difference in resistance of greater than 240 000-fold. Resistance to alpha-cypermethrin was almost 60 000-fold. This resistance was shown to be heritable, persisting after several generations of culturing. There was no evidence that resistance to organophosphorus chemicals had evolved, which is likely to be a direct consequence of the history of chemical applications these mites have experienced. These results highlight the need for more judicious management decisions in order to control pest species in a sustainable manner. The implications of these findings in regard to the management and future research of the redlegged earth mite are discussed. Copyright (c) 2007 Society of Chemical Industry.

  3. Tucker Wireline Open Hole Wireline Logging; FINAL

    International Nuclear Information System (INIS)

    Milliken, M.

    2002-01-01

    The Tucker Wireline unit ran a suite of open hole logs right behind the RMOTC logging contractor for comparison purposes. The tools included Dual Laterolog, Phased Induction, BHC Sonic, and Density-Porosity

  4. Tucker tensor analysis of Matern functions in spatial statistics

    KAUST Repository

    Litvinenko, Alexander

    2018-04-20

    Low-rank Tucker tensor methods in spatial statistics 1. Motivation: improve statistical models 2. Motivation: disadvantages of matrices 3. Tools: Tucker tensor format 4. Tensor approximation of Matern covariance function via FFT 5. Typical statistical operations in Tucker tensor format 6. Numerical experiments

  5. Tucker Tensor analysis of Matern functions in spatial statistics

    KAUST Repository

    Litvinenko, Alexander; Keyes, David E.; Khoromskaia, Venera; Khoromskij, Boris N.; Matthies, Hermann G.

    2018-01-01

    in a low-rank tensor format. We apply the Tucker and canonical tensor decompositions to a family of Matern- and Slater-type functions with varying parameters and demonstrate numerically that their approximations exhibit exponentially fast convergence

  6. Van Varroa jacobsoni naar Varroa destructor

    NARCIS (Netherlands)

    Calis, Johan

    2002-01-01

    Resultaten van onderzoek naar de verschillende voortplantingsstrategieën van Varroa jacobsoni en Varroa destructor in respectievelijk de Oosterse honigbij (Apis cerana) en de Westerse honingbij (Apis mellifera). Het hygiënisch gedrag van de Oosterse honingbij (leegruimen van aangetaste

  7. Tucker Tensor analysis of Matern functions in spatial statistics

    KAUST Repository

    Litvinenko, Alexander

    2018-03-09

    In this work, we describe advanced numerical tools for working with multivariate functions and for the analysis of large data sets. These tools will drastically reduce the required computing time and the storage cost, and, therefore, will allow us to consider much larger data sets or finer meshes. Covariance matrices are crucial in spatio-temporal statistical tasks, but are often very expensive to compute and store, especially in 3D. Therefore, we approximate covariance functions by cheap surrogates in a low-rank tensor format. We apply the Tucker and canonical tensor decompositions to a family of Matern- and Slater-type functions with varying parameters and demonstrate numerically that their approximations exhibit exponentially fast convergence. We prove the exponential convergence of the Tucker and canonical approximations in tensor rank parameters. Several statistical operations are performed in this low-rank tensor format, including evaluating the conditional covariance matrix, spatially averaged estimation variance, computing a quadratic form, determinant, trace, loglikelihood, inverse, and Cholesky decomposition of a large covariance matrix. Low-rank tensor approximations reduce the computing and storage costs essentially. For example, the storage cost is reduced from an exponential O(n^d) to a linear scaling O(drn), where d is the spatial dimension, n is the number of mesh points in one direction, and r is the tensor rank. Prerequisites for applicability of the proposed techniques are the assumptions that the data, locations, and measurements lie on a tensor (axes-parallel) grid and that the covariance function depends on a distance, ||x-y||.

  8. Field efficacy of acaricides against Varroa destructor.

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    María Jesús Gracia

    Full Text Available Field trials were conducted in Northeast Spain (Aragón to evaluate the effectiveness of two acaricides against Varroa destructor. These experiments took into account the season of the year, apiary, colony, and developmental state and strength of the colony. The acaricides used were a synthetic (amitraz, Apivar® and a natural (formulated from Api Life Var®, thymol oil and thymol alcohol product. The treatments used in the present study reduce high infestations of V. destructor, although they do not eliminate the infestation. Similar efficacies between treatments were found. Nevertheless, the efficacy of a treatment depends on the apiary where applied. Moreover, the detected variability in the apiary and hive poses a challenge to the identification of the significant factors. Therefore, more field studies to assess efficacies in several apiaries are needed to obtain a better understanding of the effects of the applied treatments.

  9. Diagenesis and sedimentology of the Clearwater Formation at Tucker Lake

    Energy Technology Data Exchange (ETDEWEB)

    Hutcheon, I; Abercrombie, H J; Putnam, P; Gardner, R; Krouse, H R

    1989-03-01

    The Clearwater Formation at Tucker Lake Alberta, contains heavy oil and is the site of a steam simulation pilot. The best developed reservoir intervals are north-south oriented distributary channel fill and rivermouth bar sand-stones. Oil bearing sands are underlain by a water zone and calcite cements are more abundant in the transition zone. Mineralogy and petrography were studied by x-ray diffraction analysis and scanning electron microscopy, and carbon and oxygen isotope ratios were measured for calcite in the samples studied. The diagenetic history is complex. Early diagenetic minerals include pyrite, quarts, K-feldspar and albite overgrowths, isopachous calcite, iron-rich chlorite, siderite and smectite. Further burial and modification of fluid composition resulted in dissolution of framework mineral grains and precipitation of clinoptilolite and opal. The emplacement of oil retarded mineral diageneses, and was accompanied by a change in aqeous fluid composition. Kaolinite was deposited during and after oil deposition as relativley fresh water entered the Clearwater Formation. The degradation and fermentation of oil and introduction of meteoric water resulted in the production of a late, isotopically distinct, post-bitumen calite cement. 29 refs., 12 figs.

  10. [Morphological observation on hypopus of Lepidoglyphus destructor by optical microscope].

    Science.gov (United States)

    Yong, H; Ning, T; Qiang, C; Chao-Pin, L I

    2017-07-03

    Objective To observe the external morphology of Lepidoglyphus destructor hypopus under an optical microscope. Methods The samples were collected in a store of Chinese medicinal herbs in Huainan City in September, 2016, the L. destructor and the hypopus were isolated, and then made of slide specimens. The slide samples were prepared and observed under an optical microscope. Results The L. destructor hypopus and protonymph were found. The inactive hypopus was oval in shape, the feet were not welldeveloped, there was a distinct transverse seam on its back, and there were 2 pairs of genital sensory organs. Conclusion The optical microscopy shows the morphological characteristics of L. destructor hypopus, which can provide the basis for the biological classification and the prevention.

  11. Immunotherapy with the storage mite lepidoglyphus destructor.

    Science.gov (United States)

    Armentia-Medina, A; Tapias, J A; Martín, J F; Ventas, P; Fernández, A

    1995-01-01

    We carried out a double-blind clinical trial of immunotherapy on 35 patients sensitized to the storage mite Lepidoglyphus destructor (Ld). Before and after 12 months of specific hyposensitization (Abelló Lab., Spain) we performed in vivo (skin tests with Ld, methacholine and challenge tests), and in vitro tests (specific IgE, IgG, IgG1 and IgG4 to Ld and specific IgE, IgG, IgG1 and IgG4 to their major allergen Lep dI). We also monitored the efficacy and safety of the immunotherapy with clinical and analytical controls (symptoms and medication score, detection of immune complexes). After therapy we found a significant decrease in specific skin reactivity, dose of positive challenge tests, and hyperresponsiveness to methacholine. Sputum eosinophilia decreased. Specific IgE to Ld was increased and we also observed an increase in specific IgG1 and IgG4 to Ld and Lep DI. The placebo group showed no changes in these variables. There were no severe secondary reactions after treatment with the extract. Patients-self-evaluation was favourable and their labour absence decreased. No development of circulating immune complexes was associated with this immunotherapy.

  12. Biology and control of Varroa destructor.

    Science.gov (United States)

    Rosenkranz, Peter; Aumeier, Pia; Ziegelmann, Bettina

    2010-01-01

    The ectoparasitic honey bee mite Varroa destructor was originally confined to the Eastern honey bee Apis cerana. After a shift to the new host Apis mellifera during the first half of the last century, the parasite dispersed world wide and is currently considered the major threat for apiculture. The damage caused by Varroosis is thought to be a crucial driver for the periodical colony losses in Europe and the USA and regular Varroa treatments are essential in these countries. Therefore, Varroa research not only deals with a fascinating host-parasite relationship but also has a responsibility to find sustainable solutions for the beekeeping. This review provides a survey of the current knowledge in the main fields of Varroa research including the biology of the mite, damage to the host, host tolerance, tolerance breeding and Varroa treatment. We first present a general view on the functional morphology and on the biology of the Varroa mite with special emphasis on host-parasite interactions during reproduction of the female mite. The pathology section describes host damage at the individual and colony level including the problem of transmission of secondary infections by the mite. Knowledge of both the biology and the pathology of Varroa mites is essential for understanding possible tolerance mechanisms in the honey bee host. We comment on the few examples of natural tolerance in A. mellifera and evaluate recent approaches to the selection of Varroa tolerant honey bees. Finally, an extensive listing and critical evaluation of chemical and biological methods of Varroa treatments is given. This compilation of present-day knowledge on Varroa honey bee interactions emphasizes that we are still far from a solution for Varroa infestation and that, therefore, further research on mite biology, tolerance breeding, and Varroa treatment is urgently needed. Copyright 2009 Elsevier Inc. All rights reserved.

  13. Challenges for developing biopesticides against Varroa destructor (Mesostigamata: Varroidae)

    Science.gov (United States)

    Control of the major pest of apiculture, the ectoparasitic mite Varroa destructor, using biopesticides would resolve many of the problems experienced with other forms of control, such as chemical control, hive manipulation or selection of resistant strains. Several research groups have developed and...

  14. APLIKASI METODE KHUN-TUCKER DALAM PENJUALAN OLI MOBIL (Studi Kasus : PT. Anugrah Mitra Dewata

    Directory of Open Access Journals (Sweden)

    Ni Made Asih

    2012-11-01

    Full Text Available Aplikasikan Metode Khun-Tucker dalam kasus penjualan oli mobil padaPT. Anugrah Mitra Dewata merupakan salah satu kasus optimasi bersyarat, untukmengetahui oli apa yang harus diproduksi oleh perusahaan, agar mencapai keuntunganmaksimal dan nilai-nilai ekstrim yang akan diperoleh, yang nantinya berperandalam menentukan tingkat keuntungan yang diperoleh perusahaan. Metode Khun-Tucker ini dapat dipergunakan untuk mencari solusi optimal dari suatu fungsi tanpamemandang sifat apakah linier atau nonlinier. Dalam proses pengerjaannya MetodeKhun-Tucker secara esensial melibatkan langkah-langkah yang sama seperti halnyaMerode Lagrange, yaitu: Membentuk Lagrangian untuk dapat menghitungtitik-titik kritisnya, mencari semua solusi (x; , dan menghitung nilai f(x. Dalamproses pencarian semua solusi x dan nya dibantu dengan menggunakan programMATLAB. Hasil penelitian menunjukkan pada caturwulan I dengan memproduksioli SMO HP sebanyak 587 liter diperoleh keuntungan maksimal perusahaansebesar Rp 19.837.000 . Untuk caturwulan II dengan memproduksi oli SMO HPPLUS sebanyak 776 liter diperoleh keuntungan maksimal perusahaan sebesar Rp20.112.000. Untuk caturwulan III dengan memproduksi oli SMO HP sebanyak 470liter diperoleh keuntungan maksimal perusahaan sebesar Rp 20.029.000.

  15. Lepidoglyphus destructor acarus in the urban house environment.

    Science.gov (United States)

    Juliá, J C; Martorell, A; Ventas, P; Cerdá, J C; Torró, I; Carreira, J; Guinot, E; Sanz, J; Alvarez, V

    1995-01-01

    To assess the presence of Lepidoglyphus destructor in the household environment of sensitized children living in an urban environment, samples of house dust were collected at the homes where two groups of patients were living, as well as in two bakeries in the city of Valencia, which were taken as a reference. Patients were divided into two groups. Group A included atopic children suffering from rhinitis and/or asthma, who were sensitized to L. destructor, as proven by prick test and specific IgE (CAP). Group B included children with the same features as those included in Group A, who were sensitized to Dermatophagoides pteronyssinus, with prick and CAP tests showing no significant sensitization to L. destructor. The samples of dust were analyzed, and the amounts of Der p I, Der f I, Der II and Lep d I per gram of dust were assessed through a solid-phase ELISA with monoclonal antibodies. In Group A, all patients but two showed a sensitization to D. pteronyssinus by prick test and serum IgE. At the homes of the patients from both groups, significant levels of Dermatophagoides were found. In Group A, only three houses showed levels of L. destructor which were comparable to those found in bakeries. Lep d I was not found in the houses of Group B patients. This means that a sensitization to L. destructor, as assessed with full extracts, is not always an indicator of its presence at the patient's house environment; it may rather refer to cross-reactivity to Dermatophagoides. Thus, availability of the main antigen Lep d I seems necessary to increase the specificity of the allergologic study.

  16. Isolation of oxalotrophic bacteria associated with Varroa destructor mites.

    Science.gov (United States)

    Maddaloni, M; Pascual, D W

    2015-11-01

    Bacteria associated with varroa mites were cultivated and genotyped by 16S RNA. Under our experimental conditions, the cultivable bacteria were few in number, and most of them proved to be fastidious to grow. Cultivation with seven different media under O2 /CO2 conditions and selection for colony morphology yielded a panel of species belonging to 13 different genera grouped in two different phyla, proteobacteria and actinobacteria. This study identified one species of actinobacteria that is a known commensal of the honey bee. Some isolates are oxalotrophic, a finding that may carry ramifications into the use of oxalic acid to control the number of phoretic mites in the managed colonies of honey bees. Oxalic acid, legally or brevi manu, is widely used to control phoretic Varroa destructor mites, a major drive of current honey bees' colony losses. Unsubstantiated by sanctioned research are rumours that in certain instances oxalic acid is losing efficacy, forcing beekeepers to increase the frequency of treatments. This investigation fathoms the hypothesis that V. destructor associates with bacteria capable of degrading oxalic acid. The data show that indeed oxalotrophy, a rare trait among bacteria, is common in bacteria that we isolated from V. destructor mites. This finding may have ramifications in the use of oxalic acid as a control agent. © 2015 The Society for Applied Microbiology.

  17. OPTIMALISASI PENJUALAN KAIN ENDEK DENGAN METODE KARUSH-KUHN-TUCKER (KKT

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    I GEDE ARIS JANOVA PUTRA

    2015-11-01

    Full Text Available This study is conducted to determine the optimal sales value of endek mastuli, endek rangrang, endek saraswati, endek gradasi, and endek alam in Novala Busana Shop and Trans Collection Shop in order to reache maximum advantage by using Karush-Kuhn-Tucker (KKT method. Karush-Khun-Tucker method can be used to find the optimum solution of the function regardless of whether linear or nonlinear. In the workmanship is KKT method essentially involves the same steps as Lagrange method, from a Lagrangean to be able to calculate the critical points, finding all solutions , and calculate of the value . In this study, most of quarterly show that which must be sold are kind of endek mastuli in reaching the maximum benefit. For other kinds of endek is constantly provided but it is not as much as before. Suggested to the next research could involve more variated variable with more interesting cases

  18. MR-NTD: Manifold Regularization Nonnegative Tucker Decomposition for Tensor Data Dimension Reduction and Representation.

    Science.gov (United States)

    Li, Xutao; Ng, Michael K; Cong, Gao; Ye, Yunming; Wu, Qingyao

    2017-08-01

    With the advancement of data acquisition techniques, tensor (multidimensional data) objects are increasingly accumulated and generated, for example, multichannel electroencephalographies, multiview images, and videos. In these applications, the tensor objects are usually nonnegative, since the physical signals are recorded. As the dimensionality of tensor objects is often very high, a dimension reduction technique becomes an important research topic of tensor data. From the perspective of geometry, high-dimensional objects often reside in a low-dimensional submanifold of the ambient space. In this paper, we propose a new approach to perform the dimension reduction for nonnegative tensor objects. Our idea is to use nonnegative Tucker decomposition (NTD) to obtain a set of core tensors of smaller sizes by finding a common set of projection matrices for tensor objects. To preserve geometric information in tensor data, we employ a manifold regularization term for the core tensors constructed in the Tucker decomposition. An algorithm called manifold regularization NTD (MR-NTD) is developed to solve the common projection matrices and core tensors in an alternating least squares manner. The convergence of the proposed algorithm is shown, and the computational complexity of the proposed method scales linearly with respect to the number of tensor objects and the size of the tensor objects, respectively. These theoretical results show that the proposed algorithm can be efficient. Extensive experimental results have been provided to further demonstrate the effectiveness and efficiency of the proposed MR-NTD algorithm.

  19. Las condiciones de Kuhn y Tucker en el cálculo de fronteras eficientes

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    Liern, Vicente

    2009-01-01

    Full Text Available Presentamos un algoritmo que combina el uso de las condiciones de Kuhn y Tucker con procedimientos heurísticos para calcular la frontera eficiente del problema de selección de cartera con variables semicontinuas y cualquier conjunto adicional de restricciones lineales. También permite incorporar otras clases de restricciones, como las de cardinalidad. Para instancias pequeñas se convierte en un algoritmo exacto. De este modo se pueden detectar muchas irregularidades de la frontera eficiente que pueden ser útiles al inversor para determinar su nivel de rentabilidad deseado. ABSTRACT We present an algorithm that combines the use of the Kuhn-Tucker conditions with heuristical procedures to calculate the efficient frontier of the semicontinuous variable constrained portfolio selection problem with any additional set of linear constraints. Other kinds of constraints can also be added, such as cardinality constraints. For small instances, it becomes an exact algoritm. In this way, many irregularities of the efficient frontier are detected that can be useful to the investor to select a desired return level.

  20. DMOs and Rural Tourism: A Stakeholder Analysis the Case of Tucker County, West Virginia

    Directory of Open Access Journals (Sweden)

    Doug Arbogast

    2017-10-01

    Full Text Available Rural destination management organizations (DMOs are faced with considerable challenges as they attempt to promote economic prosperity through tourism. This study sought to identify rural destination management challenges in Tucker County, West Virginia; identify the roles and activities of the destinations DMOs in addressing these challenges; and develop a perceived destination management framework. DMO challenges include maintaining authenticity and sense of place; economic diversification; seasonality, low wage jobs, and lack of employees; connecting resorts to small businesses and communities; and establishing a common vision, identity, and coordination of activities. While the majority of tourism literature calls for DMOs to play a dual marketing and management role, this paper makes an important contribution by identifying the need for a Convention and Visitors Bureau and a separate organization with a specific mission to sustainably develop and manage tourism and coordinate activities of the stakeholder network.

  1. Analysis of Cine-Psychometric Visual Memory Data by the Tucker Generalized Learning Curve Method: Final Report.

    Science.gov (United States)

    Reid, J. C.; Seibert, Warren F.

    The analysis of previously obtained data concerning short-term visual memory and cognition by a method suggested by Tucker is proposed. Although interesting individual differences undoubtedly exist in people's ability and capacity to process short-term visual information, studies have not generally examined these differences. In fact, conventional…

  2. Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut.

    Science.gov (United States)

    De Waele, D; Jordaan, E M; Basson, S

    1990-07-01

    The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed species; population densities increased in peanut hulls and caused severe damage to seeds of peanut grown after weeds. Roots of purple nutsedge left in the soil suppressed populations of D. destructor and root and pod development in peanut grown after the weed. However, nematode populations in peanut hulls and seeds were not suppressed. Some weed species, especially purple nutsedge which is common in peanut fields, can be used to indicate the presence of D. destructor in the absence of peanut.

  3. Viral epidemiology of the adult Apis Mellifera infested by the Varroa destructor mite

    OpenAIRE

    Bernardi, Sara; Venturino, Ezio

    2016-01-01

    The ectoparasitic mite Varroa destructor has become one of the major worldwide threats for apiculture. Varroa destructor attacks the honey bee Apis mellifera weakening its host by sucking hemolymph. However, the damage to bee colonies is not strictly related to the parasitic action of the mite but it derives, above all, from its action as vector increasing the transmission of many viral diseases such as acute paralysis (ABPV) and deformed wing viruses (DWV), that are considered among the main...

  4. Host Status of Seven Weed Species and Their Effects on Ditylenchus destructor Infestation of Peanut

    OpenAIRE

    De Waele, D.; Jordaan, Elizabeth M.; Basson, Selmaré

    1990-01-01

    The host suitability to Ditylenchus destructor of seven common weed species in peanut (Arachis hypogaea) fields in South Africa was determined. Based on the number of nematodes per root unit, white goosefoot (Chenopodium album), feathertop chloris (Chloris virgata), purple nutsedge (Cyperus rotundus), jimson weed (Datura stramonium), goose grass (Eleusine indica), khaki weed (Tagetes minuta), and cocklebur (Xanthium strumarium) were poor hosts. Ditylenchus destructor survived on all weed spec...

  5. Purification and characterization of Lep d I, a major allergen from the mite Lepidoglyphus destructor.

    Science.gov (United States)

    Ventas, P; Carreira, J; Polo, F

    1992-04-01

    A major allergen of the storage mite Lepidoglyphus destructor (Lep d I) has been purified by affinity chromatography using an anti-Lep d I monoclonal antibody. The purity of the protein obtained by this procedure was assessed by reverse-phase HPLC. Lep d I displayed a molecular weight of 14 kD on SDS-PAGE under non-reducing conditions, and 16 kD in the presence of a reducing agent. Analytical IEF revealed a little charge microheterogeneity, showing three bands with pIs 7.6-7.8. Purified Lep d I retained IgE-binding ability, as proved by immunoblotting experiments after SDS-PAGE and RAST with individual sera from L. destructor-sensitive patients. Results from the latter technique demonstrated that 87% of L. destructor-allergic patients had specific IgE to Lep d I, and a good correlation between IgE reactivity with L. destructor extract and Lep d I was found. In addition, RAST inhibition experiments showed that IgE-binding sites on Lep d I are major L. destructor-allergenic determinants, since Lep d I could inhibit up to 75% the binding of specific IgE to L. destructor extract; on the other hand, Lep d I did not cross-react with D. pteronyssinus allergens.

  6. Compression of Multispectral Images with Comparatively Few Bands Using Posttransform Tucker Decomposition

    Directory of Open Access Journals (Sweden)

    Jin Li

    2014-01-01

    Full Text Available Up to now, data compression for the multispectral charge-coupled device (CCD images with comparatively few bands (MSCFBs is done independently on each multispectral channel. This compression codec is called a “monospectral compressor.” The monospectral compressor does not have a removing spectral redundancy stage. To fill this gap, we propose an efficient compression approach for MSCFBs. In our approach, the one dimensional discrete cosine transform (1D-DCT is performed on spectral dimension to exploit the spectral information, and the posttransform (PT in 2D-DWT domain is performed on each spectral band to exploit the spatial information. A deep coupling approach between the PT and Tucker decomposition (TD is proposed to remove residual spectral redundancy between bands and residual spatial redundancy of each band. Experimental results on multispectral CCD camera data set show that the proposed compression algorithm can obtain a better compression performance and significantly outperforms the traditional compression algorithm-based TD in 2D-DWT and 3D-DCT domain.

  7. Group search optimiser-based optimal bidding strategies with no Karush-Kuhn-Tucker optimality conditions

    Science.gov (United States)

    Yadav, Naresh Kumar; Kumar, Mukesh; Gupta, S. K.

    2017-03-01

    General strategic bidding procedure has been formulated in the literature as a bi-level searching problem, in which the offer curve tends to minimise the market clearing function and to maximise the profit. Computationally, this is complex and hence, the researchers have adopted Karush-Kuhn-Tucker (KKT) optimality conditions to transform the model into a single-level maximisation problem. However, the profit maximisation problem with KKT optimality conditions poses great challenge to the classical optimisation algorithms. The problem has become more complex after the inclusion of transmission constraints. This paper simplifies the profit maximisation problem as a minimisation function, in which the transmission constraints, the operating limits and the ISO market clearing functions are considered with no KKT optimality conditions. The derived function is solved using group search optimiser (GSO), a robust population-based optimisation algorithm. Experimental investigation is carried out on IEEE 14 as well as IEEE 30 bus systems and the performance is compared against differential evolution-based strategic bidding, genetic algorithm-based strategic bidding and particle swarm optimisation-based strategic bidding methods. The simulation results demonstrate that the obtained profit maximisation through GSO-based bidding strategies is higher than the other three methods.

  8. Fluorescent fingerprints of edible oils and biodiesel by means total synchronous fluorescence and Tucker3 modeling

    Science.gov (United States)

    Insausti, Matías; de Araújo Gomes, Adriano; Camiña, José Manuel; de Araújo, Mario Cesar Ugulino; Band, Beatriz Susana Fernández

    2017-03-01

    The present work proposes the use of total synchronous fluorescence spectroscopy (TSFS) as a discrimination methodology for fluorescent compounds in edible oils, which are preserved after the transesterification processes in the biodiesel production. In the same way, a similar study is presented to identify fluorophores that do not change in expired vegetal oils, to associate physicochemical parameters to fluorescent measures, as contribution to a fingerprint for increasing the chemical knowledge of these products. The fluorescent fingerprints were obtained by Tucker3 decomposition of a three-way array of the total synchronous fluorescence matrices. This chemometric method presents the ability for modeling non-bilinear data, as Total Synchronous Fluorescence Spectra data, and consists in the decomposition of the three way data arrays (samples × Δλ × λ excitation), into four new data matrices: A (scores), B (profile in Δλ mode), C (profile in spectra mode) and G (relationships between A, B and C). In this study, 50 samples of oil from soybean, corn and sunflower seeds before and after its expiration time, as well as 50 biodiesel samples obtained by transesterification of the same oils were measured by TSFS. This study represents an immediate application of chemical fingerprint for the discrimination of non-expired and expired edible oils and biodiesel. This method does not require the use of reagents or laborious procedures for the chemical characterization of samples.

  9. A fiber orientation-adapted integration scheme for computing the hyperelastic Tucker average for short fiber reinforced composites

    Science.gov (United States)

    Goldberg, Niels; Ospald, Felix; Schneider, Matti

    2017-10-01

    In this article we introduce a fiber orientation-adapted integration scheme for Tucker's orientation averaging procedure applied to non-linear material laws, based on angular central Gaussian fiber orientation distributions. This method is stable w.r.t. fiber orientations degenerating into planar states and enables the construction of orthotropic hyperelastic energies for truly orthotropic fiber orientation states. We establish a reference scenario for fitting the Tucker average of a transversely isotropic hyperelastic energy, corresponding to a uni-directional fiber orientation, to microstructural simulations, obtained by FFT-based computational homogenization of neo-Hookean constituents. We carefully discuss ideas for accelerating the identification process, leading to a tremendous speed-up compared to a naive approach. The resulting hyperelastic material map turns out to be surprisingly accurate, simple to integrate in commercial finite element codes and fast in its execution. We demonstrate the capabilities of the extracted model by a finite element analysis of a fiber reinforced chain link.

  10. VALUING BENEFITS FROM WATER QUALITY IMPROVEMENTS USING KUHN TUCKER MODEL - A COMPARATIVE ANALYSIS ON UTILITY FUNCTIONAL FORMS-

    Science.gov (United States)

    Okuyama, Tadahiro

    Kuhn-Tucker model, which has studied in recent years, is a benefit valuation technique using the revealed-preference data, and the feature is to treatvarious patterns of corner solutions flexibly. It is widely known for the benefit calculation using the revealed-preference data that a value of a benefit changes depending on a functional form. However, there are little studies which examine relationship between utility functions and values of benefits in Kuhn-Tucker model. The purpose of this study is to analysis an influence of the functional form to the value of a benefit. Six types of utility functions are employed for benefit calculations. The data of the recreational activity of 26 beaches of Miyagi Prefecture were employed. Calculation results indicated that Phaneuf and Siderelis (2003) and Whitehead et al.(2010)'s functional forms are useful for benefit calculations.

  11. Winter Survival of Individual Honey Bees and Honey Bee Colonies Depends on Level of Varroa destructor Infestation

    NARCIS (Netherlands)

    Dooremalen, van C.; Gerritsen, L.J.M.; Cornelissen, B.; Steen, van der J.J.M.; Langevelde, van F.; Blacquiere, T.

    2012-01-01

    Background: Recent elevated winter loss of honey bee colonies is a major concern. The presence of the mite Varroa destructor in colonies places an important pressure on bee health. V. destructor shortens the lifespan of individual bees, while long lifespan during winter is a primary requirement to

  12. Palaeomagnetism of the Early Permian Mount Leyshon Intrusive Complex and Tuckers Igneous Complex, North Queensland, Australia

    Science.gov (United States)

    Clark, D. A.; Lackie, M. A.

    2003-06-01

    This study provides reliable, precisely defined and well-dated Early Permian (286 +/- 6 Ma) palaeomagnetic poles for Australia from the Mount Leyshon Intrusive Complex (MLIC) and the Tuckers Igneous Complex (TIC). Both complexes are associated with prominent negative magnetic anomalies, indicating the presence of rocks carrying stable remanence of reverse polarity, with a Koenigsberger ratio greater than unity. The characteristic remanence carried by the intrusive phases and by locally remagnetized, contact-metamorphosed host rocks is always of reverse polarity, consistent with acquisition during the Permo-Carboniferous (Kiaman) Reverse Superchron. The corresponding palaeopoles confirm that Australia occupied high latitudes in the Early Permian. The pole positions are: MLIC: lat. = 43.2 °S, long. = 137.3 °E dp = 6.0°, dm = 6.4° Q= 6; TIC: lat. = 47.5 °S, long. = 143.0 °E, dp = 6.0°, dm = 6.6° Q= 6. Permian palaeomagnetic overprinting is detectable at considerable distances from the MLIC (2-3 km), well beyond the zone of visible alteration. The primary nature of the Early Permian palaeomagnetic signature is established by full baked contact/aureole tests at both localities. Other new data from Australia are consistent with the poles reported here. Comparison of the Australian, African and South American Apparent Polar Wander Paths (APWP) suggests that mean Permian and Triassic poles from West Gondwana, particularly from South America, are biased by remagnetization in the Jurassic-Cretaceous and that the Late Palaeozoic-Mesozoic APWP for Gondwana is best defined by Australian data. The Australian APWP exhibits substantial movement through the Mesozoic. Provided only that the time-averaged palaeofield was zonal, the Early Triassic palaeomagnetic data from Australia provide an important palaeogeographic constraint that the south geographic pole was within, or very close to, SE Australia around 240 Ma. The new Early Permian poles are apparently more consistent

  13. Simultaneous measurement of two enzyme activities using infrared spectroscopy: A comparative evaluation of PARAFAC, TUCKER and N-PLS modeling.

    Science.gov (United States)

    Baum, Andreas; Hansen, Per Waaben; Meyer, Anne S; Mikkelsen, Jørn Dalgaard

    2013-08-06

    Enzymes are used in many processes to release fermentable sugars for green production of biofuel, or the refinery of biomass for extraction of functional food ingredients such as pectin or prebiotic oligosaccharides. The complex biomasses may, however, require a multitude of specific enzymes which are active on specific substrates generating a multitude of products. In this paper we use the plant polymer, pectin, to present a method to quantify enzyme activity of two pectolytic enzymes by monitoring their superimposed spectral evolutions simultaneously. The data is analyzed by three chemometric multiway methods, namely PARAFAC, TUCKER3 and N-PLS, to establish simultaneous enzyme activity assays for pectin lyase and pectin methyl esterase. Correlation coefficients Rpred(2) for prediction test sets are 0.48, 0.96 and 0.96 for pectin lyase and 0.70, 0.89 and 0.89 for pectin methyl esterase, respectively. The retrieved models are compared and prediction test sets show that especially TUCKER3 performs well, even in comparison to the supervised regression method N-PLS. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Comparative testing of different methods for evaluation of Varroa destructor infestation of honey bee colonies

    Directory of Open Access Journals (Sweden)

    Nikolay D. Dobrynin

    2011-09-01

    Full Text Available Different methods for evaluation of the degree of Varroa destructor infestation of honey bee colonies were tested. The methods using in vivo evaluation were the most sparing for the bees but less precise. The methods using evaluation with the killing of the bees or brood were the most precise but less sparing for bees.

  15. Brain metabolomic profiling of eastern honey bee (Apis cerana infested with the mite Varroa destructor.

    Directory of Open Access Journals (Sweden)

    Jiang-Li Wu

    Full Text Available The mite Varroa destructor is currently the greatest threat to apiculture as it is causing a global decrease in honey bee colonies. However, it rarely causes serious damage to its native hosts, the eastern honey bees Apis cerana. To better understand the mechanism of resistance of A. cerana against the V. destructor mite, we profiled the metabolic changes that occur in the honey bee brain during V. destructor infestation. Brain samples were collected from infested and control honey bees and then measured using an untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS-based global metabolomics method, in which 7918 and 7462 ions in ESI+ and ESI- mode, respectively, were successfully identified. Multivariate statistical analyses were applied, and 64 dysregulated metabolites, including fatty acids, amino acids, carboxylic acid, and phospholipids, amongst others, were identified. Pathway analysis further revealed that linoleic acid metabolism; propanoate metabolism; and glycine, serine, and threonine metabolism were acutely perturbed. The data obtained in this study offer insight into the defense mechanisms of A. cerana against V. destructor mites and provide a better method for understanding the synergistic effects of parasitism on honey bee colonies.

  16. Naturally selected honey bee (Apis mellifera) colonies resistant to Varroa destructor do not groom more intensively

    NARCIS (Netherlands)

    Kruitwagen, Astrid; Langevelde, van Frank; Dooremalen, van Coby; Blacquière, Tjeerd

    2017-01-01

    The ectoparasitic mite Varroa destructor is an important cause of high colony losses of the honey bee Apis mellifera. In The Netherlands, two resistant A. mellifera populations developed naturally after ceasing varroa control. As a result, mite infestation levels of the colonies of these populations

  17. Honey bee Apis mellifera parasites in the absence of Nosema ceranae fungi and Varroa destructor mites.

    Science.gov (United States)

    Shutler, Dave; Head, Krista; Burgher-MacLellan, Karen L; Colwell, Megan J; Levitt, Abby L; Ostiguy, Nancy; Williams, Geoffrey R

    2014-01-01

    Few areas of the world have western honey bee (Apis mellifera) colonies that are free of invasive parasites Nosema ceranae (fungi) and Varroa destructor (mites). Particularly detrimental is V. destructor; in addition to feeding on host haemolymph, these mites are important vectors of several viruses that are further implicated as contributors to honey bee mortality around the world. Thus, the biogeography and attendant consequences of viral communities in the absence of V. destructor are of significant interest. The island of Newfoundland, Province of Newfoundland and Labrador, Canada, is free of V. destructor; the absence of N. ceranae has not been confirmed. Of 55 Newfoundland colonies inspected visually for their strength and six signs of disease, only K-wing had prevalence above 5% (40/55 colonies = 72.7%). Similar to an earlier study, screenings again confirmed the absence of V. destructor, small hive beetles Aethina tumida (Murray), tracheal mites Acarapis woodi (Rennie), and Tropilaelaps spp. ectoparasitic mites. Of a subset of 23 colonies screened molecularly for viruses, none had Israeli acute paralysis virus, Kashmir bee virus, or sacbrood virus. Sixteen of 23 colonies (70.0%) were positive for black queen cell virus, and 21 (91.3%) had some evidence for deformed wing virus. No N. ceranae was detected in molecular screens of 55 colonies, although it is possible extremely low intensity infections exist; the more familiar N. apis was found in 53 colonies (96.4%). Under these conditions, K-wing was associated (positively) with colony strength; however, viruses and N. apis were not. Furthermore, black queen cell virus was positively and negatively associated with K-wing and deformed wing virus, respectively. Newfoundland honey bee colonies are thus free of several invasive parasites that plague operations in other parts of the world, and they provide a unique research arena to study independent pathology of the parasites that are present.

  18. Evidence for passive chemical camouflage in the parasitic mite Varroa destructor.

    Science.gov (United States)

    Kather, Ricarda; Drijfhout, Falko P; Shemilt, Sue; Martin, Stephen J

    2015-02-01

    Social insect colonies provide a stable and safe environment for their members. Despite colonies being heavily guarded, parasites have evolved numerous strategies to invade and inhabit these hostile places. Two such strategies are (true) chemical mimicry via biosynthesis of host odor, and chemical camouflage, in which compounds are acquired from the host. The ectoparasitic mite Varroa destructor feeds on hemolymph of its honey bee host, Apis mellifera. The mite's odor closely resembles that of its host, which allows V. destructor to remain undetected as it lives on the adult host during its phoretic phase and while reproducing on the honeybee brood. During the mite life cycle, it switches between host adults and brood, which requires it to adjust its profile to mimic the very different odors of honey bee brood and adults. In a series of transfer experiments, using bee adults and pupae, we tested whether V. destructor changes its profile by synthesizing compounds or by using chemical camouflage. We show that V. destructor required direct access to host cuticle to mimic its odor, and that it was unable to synthesize host-specific compounds itself. The mite was able to mimic host odor, even when dead, indicating a passive physico-chemical mechanism of the parasite cuticle. The chemical profile of V. destructor was adjusted within 3 to 9 h after switching hosts, demonstrating that passive camouflage is a highly efficient, fast and flexible way for the mite to adapt to a new host profile when moving between different host life stages or colonies.

  19. Simultaneous measurement of two enzyme activities using infrared spectroscopy: A comparative evaluation of PARAFAC, TUCKER and N-PLS modeling

    DEFF Research Database (Denmark)

    Baum, Andreas; Hansen, Per Waaben; Meyer, Anne S.

    2013-01-01

    multiway methods, namely PARAFAC, TUCKER3 and N-PLS, to establish simultaneous enzyme activity assays for pectin lyase and pectin methyl esterase. Correlation coefficients Rpred2 for prediction test sets are 0.48, 0.96 and 0.96 for pectin lyase and 0.70, 0.89 and 0.89 for pectin methyl esterase......Enzymes are used in many processes to release fermentable sugars for green production of biofuel, or the refinery of biomass for extraction of functional food ingredients such as pectin or prebiotic oligosaccharides. The complex biomasses may, however, require a multitude of specific enzymes which...... are active on specific substrates generating a multitude of products. In this paper we use the plant polymer, pectin, to present a method to quantify enzyme activity of two pectolytic enzymes by monitoring their superimposed spectral evolutions simultaneously. The data is analyzed by three chemometric...

  20. The Karush–Kuhn–Tucker optimality conditions in minimum weight design of elastic rotating disks with variable thickness and density

    Directory of Open Access Journals (Sweden)

    Sanaz Jafari

    2011-10-01

    Full Text Available Rotating discs work mostly at high angular velocity. High speed results in large centrifugal forces in discs and induces large stresses and deformations. Minimizing weight of such disks yields various benefits such as low dead weights and lower costs. In order to attain a certain and reliable analysis, disk with variable thickness and density is considered. Semi-analytical solutions for the elastic stress distribution in rotating annular disks with uniform and variable thicknesses and densities are obtained under plane stress assumption by authors in previous works. The optimum disk profile for minimum weight design is achieved by the Karush–Kuhn–Tucker (KKT optimality conditions. Inequality constrain equation is used in optimization to make sure that maximum von Mises stress is always less than yielding strength of the material of the disk.

  1. Varroa destructor virus 1: a new picorna-like virus in Varroa mites as well as honey bees

    OpenAIRE

    Ongus, J.R.

    2006-01-01

    Varroa destructor mite is an ectoparasite of the honey bee Apis mellifera. This species was recently differentiated from Varroa jacobsoni species which infests the Asian bee Apis cerana. Varroa mites feed entirely on the bee's haemolymph and have been associated with the spread of a number of viruses. Since the mites were first observed in Java, Indonesia in 1904, they have been reported in most regions of the world except Australia and the equatorial regions of Africa. V. destructor severely...

  2. Selection of Entomopathogenic Fungi to Control Varroa destructor (Acari: Varroidae Selección de Hongos Entomopatógenos para el Control de Varroa destructor (Acari: Varroidae

    Directory of Open Access Journals (Sweden)

    Marta Rodríguez

    2009-12-01

    Full Text Available The aim of this work was select entomopathogenic fungi tolerant to temperatures inside the brood area of honey bees (Apis mellifera for to control Varroa destructor. For this purpose, 50 Beauveria bassiana (Balsamo Vuillemin and 48 Metarhizium anisopliae (Metschn. Sorokin isolates were evaluated at 30 and 35 ºC. For each isolate, colony discs of 5 mm with mycelium were placed in the center of a Petri dish with Sabouraud dextrose agar (SDA medium. The dishes were incubated at 30 and 35 °C, without light. Radial growth of each colony was measured daily. All the B. bassiana and M. anisopliae isolates presented a lineal growth rate at a temperature of 30 ºC. However, at 35 ºC, most of the isolates did not grow, except three B. bassiana and 14 M. anisopliae isolates (P El objetivo de este trabajo fue seleccionar hongos entomopatógenos tolerantes a las temperaturas del nido de cría de las abejas (Apis mellifera, para ser utilizados en el control de Varroa destructor. Se evaluaron 50 aislamientos de Beauveria bassiana (Balsamo Vuillemin y 48 de Metarhizium anisopliae (Metschn. Sorokin a temperaturas de 30 y 35 ºC. Discos de agar de 5 mm de diámetro con micelio de colonias de cada aislamiento, se depositaron en el centro de placas Petri con medio agar Sabouraud dextrosa (ASD. Las placas fueron incubadas a 30 y 35 °C y oscuridad y diariamente se midió el radio de cada colonia. Todos los aislamientos de B. bassiana y M. anisopliae var. anisopliae presentaron una tendencia lineal a través del tiempo a temperaturas de incubación de 30 °C. A 35 °C la mayoría de los aislamientos no crecieron, excepto tres aislamientos de B. bassiana y 14 de M. anisopliae (p < 0,001. Estos aislamientos fueron seleccionados para realizar pruebas de patogenicidad sobre V. destructor, aplicando una suspensión de 10(7 conidias mL-1. El aislamiento más efectivo fue Qu-M845 de M. anisopliae (p = 0,0033, produjo una mortalidad de 85%. La capacidad patogénica de este

  3. Varroa destructor Mites Can Nimbly Climb from Flowers onto Foraging Honey Bees.

    Directory of Open Access Journals (Sweden)

    David T Peck

    Full Text Available Varroa destructor, the introduced parasite of European honey bees associated with massive colony deaths, spreads readily through populations of honey bee colonies, both managed colonies living crowded together in apiaries and wild colonies living widely dispersed in natural settings. Mites are hypothesized to spread between most managed colonies via phoretically riding forager bees when they engage in robbing colonies or they drift between hives. However, widely spaced wild colonies show Varroa infestation despite limited opportunities for robbing and little or no drifting of bees between colonies. Both wild and managed colonies may also exchange mites via another mechanism that has received remarkably little attention or study: floral transmission. The present study tested the ability of mites to infest foragers at feeders or flowers. We show that Varroa destructor mites are highly capable of phoretically infesting foraging honey bees, detail the mechanisms and maneuvers by which they do so, and describe mite behaviors post-infestation.

  4. Varroa destructor Mites Can Nimbly Climb from Flowers onto Foraging Honey Bees

    Science.gov (United States)

    Smith, Michael L.; Seeley, Thomas D.

    2016-01-01

    Varroa destructor, the introduced parasite of European honey bees associated with massive colony deaths, spreads readily through populations of honey bee colonies, both managed colonies living crowded together in apiaries and wild colonies living widely dispersed in natural settings. Mites are hypothesized to spread between most managed colonies via phoretically riding forager bees when they engage in robbing colonies or they drift between hives. However, widely spaced wild colonies show Varroa infestation despite limited opportunities for robbing and little or no drifting of bees between colonies. Both wild and managed colonies may also exchange mites via another mechanism that has received remarkably little attention or study: floral transmission. The present study tested the ability of mites to infest foragers at feeders or flowers. We show that Varroa destructor mites are highly capable of phoretically infesting foraging honey bees, detail the mechanisms and maneuvers by which they do so, and describe mite behaviors post-infestation. PMID:27942015

  5. Varroa destructor Mites Can Nimbly Climb from Flowers onto Foraging Honey Bees.

    Science.gov (United States)

    Peck, David T; Smith, Michael L; Seeley, Thomas D

    2016-01-01

    Varroa destructor, the introduced parasite of European honey bees associated with massive colony deaths, spreads readily through populations of honey bee colonies, both managed colonies living crowded together in apiaries and wild colonies living widely dispersed in natural settings. Mites are hypothesized to spread between most managed colonies via phoretically riding forager bees when they engage in robbing colonies or they drift between hives. However, widely spaced wild colonies show Varroa infestation despite limited opportunities for robbing and little or no drifting of bees between colonies. Both wild and managed colonies may also exchange mites via another mechanism that has received remarkably little attention or study: floral transmission. The present study tested the ability of mites to infest foragers at feeders or flowers. We show that Varroa destructor mites are highly capable of phoretically infesting foraging honey bees, detail the mechanisms and maneuvers by which they do so, and describe mite behaviors post-infestation.

  6. Particularité du traitement à l'acide formique de varroa destructor ...

    African Journals Online (AJOL)

    Varroa destructor est un acarien parasite de l'abeille responsable d'un affaiblissement de la colonie et suspecté d'être impliqué dans les processus de mortalités hivernales. Pour contrôler ce parasite, plusieurs scientifiques et apiculteurs ont eu recours aux produits chimiques. En dépit de leur efficacité, la répétition de ces ...

  7. Regular dorsal dimples and damaged mites of Varroa destructor in some Iranian honey bees (Apis mellifera)

    OpenAIRE

    Ardestani, Masoud M.; Ebadi, Rahim; Tahmasbi, Gholamhossein

    2011-01-01

    The frequency of damaged Varroa destructor Anderson and Trueman (Mesostigmata: Varroidae) found on the bottom board of hives of the honey bee, Apis mellifera L. (Hymenoptera: Apidae) has been used as an indicator of the degree of tolerance or resistance of honey bee colonies against mites. However, it is not clear that this measure is adequate. These injuries should be separated from regular dorsal dimples that have a developmental origin. To investigate damage to Varroa mites and regular dor...

  8. Norwegian honey bees surviving Varroa destructor mite infestations by means of natural selection

    OpenAIRE

    Oddie, Melissa AY; Dahle, Bjørn Steinar; Neumann, Peter

    2017-01-01

    Background Managed, feral and wild populations of European honey bee subspecies, Apis mellifera, are currently facing severe colony losses globally. There is consensus that the ectoparasitic mite Varroa destructor, that switched hosts from the Eastern honey bee Apis cerana to the Western honey bee A. mellifera, is a key factor driving these losses. For >20 years, breeding efforts have not produced European honey bee colonies that can survive infestations without the need for mite control....

  9. Expression and Activity of Lysozyme in Apis Mellifera Carnica Brood Infested with Varroa Destructor

    OpenAIRE

    Zaobidna Ewa A.; Żółtowska Krystyna; Łopieńska-Biernat Elżbieta

    2017-01-01

    Varroa destructor is a parasitic mite that attacks the honey bee, and previous studies have suggested that parasitosis caused by this mite is accompanied by immunosuppresion in the host. In this study, the effect of mite infestation on the expression of the lysozyme-1 (lys-1) gene and lysozyme activity in Apis mellifera carnica was determined. The experiment was carried out on the five developmental stages of honey bee workers and drones. Developmental and gender-related differences in gene e...

  10. Inside Honeybee Hives: Impact of Natural Propolis on the Ectoparasitic Mite Varroa destructor and Viruses.

    Science.gov (United States)

    Drescher, Nora; Klein, Alexandra-Maria; Neumann, Peter; Yañez, Orlando; Leonhardt, Sara D

    2017-02-06

    Social immunity is a key factor for honeybee health, including behavioral defense strategies such as the collective use of antimicrobial plant resins (propolis). While laboratory data repeatedly show significant propolis effects, field data are scarce, especially at the colony level. Here, we investigated whether propolis, as naturally deposited in the nests, can protect honeybees against ectoparasitic mites Varroa destructor and associated viruses, which are currently considered the most serious biological threat to European honeybee subspecies, Apis mellifera , globally. Propolis intake of 10 field colonies was manipulated by either reducing or adding freshly collected propolis. Mite infestations, titers of deformed wing virus (DWV) and sacbrood virus (SBV), resin intake, as well as colony strength were recorded monthly from July to September 2013. We additionally examined the effect of raw propolis volatiles on mite survival in laboratory assays. Our results showed no significant effects of adding or removing propolis on mite survival and infestation levels. However, in relation to V. destructor , DWV titers increased significantly less in colonies with added propolis than in propolis-removed colonies, whereas SBV titers were similar. Colonies with added propolis were also significantly stronger than propolis-removed colonies. These findings indicate that propolis may interfere with the dynamics of V. destructor -transmitted viruses, thereby further emphasizing the importance of propolis for honeybee health.

  11. Inside Honeybee Hives: Impact of Natural Propolis on the Ectoparasitic Mite Varroa destructor and Viruses

    Science.gov (United States)

    Drescher, Nora; Klein, Alexandra-Maria; Neumann, Peter; Yañez, Orlando; Leonhardt, Sara D.

    2017-01-01

    Social immunity is a key factor for honeybee health, including behavioral defense strategies such as the collective use of antimicrobial plant resins (propolis). While laboratory data repeatedly show significant propolis effects, field data are scarce, especially at the colony level. Here, we investigated whether propolis, as naturally deposited in the nests, can protect honeybees against ectoparasitic mites Varroa destructor and associated viruses, which are currently considered the most serious biological threat to European honeybee subspecies, Apis mellifera, globally. Propolis intake of 10 field colonies was manipulated by either reducing or adding freshly collected propolis. Mite infestations, titers of deformed wing virus (DWV) and sacbrood virus (SBV), resin intake, as well as colony strength were recorded monthly from July to September 2013. We additionally examined the effect of raw propolis volatiles on mite survival in laboratory assays. Our results showed no significant effects of adding or removing propolis on mite survival and infestation levels. However, in relation to V. destructor, DWV titers increased significantly less in colonies with added propolis than in propolis-removed colonies, whereas SBV titers were similar. Colonies with added propolis were also significantly stronger than propolis-removed colonies. These findings indicate that propolis may interfere with the dynamics of V. destructor-transmitted viruses, thereby further emphasizing the importance of propolis for honeybee health. PMID:28178181

  12. Interaction between Varroa destructor and imidacloprid reduces flight capacity of honeybees

    Science.gov (United States)

    Blanken, Lisa J.; van Dooremalen, Coby

    2015-01-01

    Current high losses of honeybees seriously threaten crop pollination. Whereas parasite exposure is acknowledged as an important cause of these losses, the role of insecticides is controversial. Parasites and neonicotinoid insecticides reduce homing success of foragers (e.g. by reduced orientation), but it is unknown whether they negatively affect flight capacity. We investigated how exposing colonies to the parasitic mite Varroa destructor and the neonicotinoid insecticide imidacloprid affect flight capacity of foragers. Flight distance, time and speed of foragers were measured in flight mills to assess the relative and interactive effects of high V. destructor load and a field-realistic, chronic sub-lethal dose of imidacloprid. Foragers from colonies exposed to high levels of V. destructor flew shorter distances, with a larger effect when also exposed to imidacloprid. Bee body mass partly explained our results as bees were heavier when exposed to these stressors, possibly due to an earlier onset of foraging. Our findings contribute to understanding of interacting stressors that can explain colony losses. Reduced flight capacity decreases the food-collecting ability of honeybees and may hamper the use of precocious foraging as a coping mechanism during colony (nutritional) stress. Ineffective coping mechanisms may lead to destructive cascading effects and subsequent colony collapse. PMID:26631559

  13. Expression and Activity of Lysozyme in Apis Mellifera Carnica Brood Infested with Varroa Destructor

    Directory of Open Access Journals (Sweden)

    Zaobidna Ewa A.

    2017-12-01

    Full Text Available Varroa destructor is a parasitic mite that attacks the honey bee, and previous studies have suggested that parasitosis caused by this mite is accompanied by immunosuppresion in the host. In this study, the effect of mite infestation on the expression of the lysozyme-1 (lys-1 gene and lysozyme activity in Apis mellifera carnica was determined. The experiment was carried out on the five developmental stages of honey bee workers and drones. Developmental and gender-related differences in gene expression and lysozyme activity were observed in a Varroa destructor-infested brood. The relative expression of the lys-1 gene increased in a infested worker brood and decreased in a drone brood except for P3 pupae. In the final stage of development, the lys-1 gene expression was significantly lower in infested newly emerged workers and drones. Changes in the relative expression of the lys-1 gene in infested individuals was poorly manifested at the level of enzyme activity, whereas at the two final stages of development (P5 and I there was a positive correlation between relative lys-1 expression and lysozyme activity in infested bees of both genders (r=0.988, r=0.999, respectively. The results of this study indicate that V. destructor influences the lysozyme-linked immune response in bees.

  14. The Ditylenchus destructor genome provides new insights into the evolution of plant parasitic nematodes.

    Science.gov (United States)

    Zheng, Jinshui; Peng, Donghai; Chen, Ling; Liu, Hualin; Chen, Feng; Xu, Mengci; Ju, Shouyong; Ruan, Lifang; Sun, Ming

    2016-07-27

    Plant-parasitic nematodes were found in 4 of the 12 clades of phylum Nematoda. These nematodes in different clades may have originated independently from their free-living fungivorous ancestors. However, the exact evolutionary process of these parasites is unclear. Here, we sequenced the genome sequence of a migratory plant nematode, Ditylenchus destructor We performed comparative genomics among the free-living nematode, Caenorhabditis elegans and all the plant nematodes with genome sequences available. We found that, compared with C. elegans, the core developmental control processes underwent heavy reduction, though most signal transduction pathways were conserved. We also found D. destructor contained more homologies of the key genes in the above processes than the other plant nematodes. We suggest that Ditylenchus spp. may be an intermediate evolutionary history stage from free-living nematodes that feed on fungi to obligate plant-parasitic nematodes. Based on the facts that D. destructor can feed on fungi and has a relatively short life cycle, and that it has similar features to both C. elegans and sedentary plant-parasitic nematodes from clade 12, we propose it as a new model to study the biology, biocontrol of plant nematodes and the interaction between nematodes and plants. © 2016 The Author(s).

  15. Second-order capillary electrophoresis diode array detector data modeled with the Tucker3 algorithm: A novel strategy for Argentinean white wine discrimination respect to grape variety.

    Science.gov (United States)

    Azcarate, Silvana M; de Araújo Gomes, Adriano; Vera-Candioti, Luciana; Cesar Ugulino de Araújo, Mário; Camiña, José M; Goicoechea, Héctor C

    2016-07-01

    Data obtained by capillary electrophoresis with diode array detection (CE-DAD) were modeled with the purpose to discriminate Argentinean white wines samples produced from three grape varieties (Torrontés, Chardonnay, and Sauvignon blanc). Thirty-eight samples of commercial white wine from four wine-producing provinces of Argentina (Mendoza, San Juan, Salta, and Rio Negro) were analyzed. CE-DAD matrices with dimensions of 421 elution times (from 1.17 to 7.39 minutes) × 71 wavelengths (from 227 to 367 nm) were joined in a three way data array and decomposed by Tucker3 method under non-negativity constraint, employing 18, 18 and six factors in the modes 1, 2 and 3, respectively. Using the scores of Tucker model, it was possible to discriminate samples of Argentinean white wine by linear discriminant analysis and Kernel linear discriminant analysis. Core element analysis of the Tucker3 model allows identifying the loading profiles in spectral mode related to Argentinean white wine samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. EFFICIENCY OF FORMING NUCLEUS COLONIES IN ORDER TO DECREASE POPULATION OF Varroa destructor (ANDRESON AND TRUEMAN, 2000 IN BEEHIVES

    Directory of Open Access Journals (Sweden)

    Zlatko Puškadija

    2003-12-01

    Full Text Available Forming of nucleus colonies is efficient method in growth control of Varroa destructor population. Its goal is to decrease parasite’s pressure on bee colony. The advantage of this bio-technical measurement lays in its implement during vegetation season which delays use of the chemical resources for Varroa destructor control population in beehives for the post major honey harvest period. Nucleus colonies were formed from approx. half of sealed brood (35.5 ± 5.8 dm² and average of 5915 ± 912 bees. Results showed that there were 37.2 ± 5.6% mites removed from parental colonies. Minimum was 30.8%, and maximum was 45.5%. Due to such relatively small efficiency, this method cannot be recommended as unique, but it can be effective if it is applied in the post spring's honey harvest period as a part of growth reduction strategy of Varroa destructor population in beehive.

  17. The effects of clove oil on the enzyme activity of Varroa destructor Anderson and Trueman (Arachnida: Acari: Varroidae

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    Li Li

    2017-07-01

    Full Text Available Varroa destructor, a key biotic threat to the Western honey bee, has played a major role in colony losses over the past few years worldwide. Overuse of traditional acaricides, such as tau-fluvalinate and flumethrin, on V. destructor has only increased its tolerance to them. Therefore, the application of essential oils in place of traditional pesticides is an attractive alternative, as demonstrated by its high efficiency, lack of residue and tolerance resistance. To study the acaricidal activity of essential oils, we used clove oil (Syzygium aromaticum L., a typical essential oil with a wide range of field applications, and examined its effects on the enzyme activities of Ca2+-Mg2+-ATPase, glutathione-S-transferase (GST and superoxide dismutase (SOD and its effects on the water-soluble protein content of V. destructor body extracts after exposure to 0.1 μl and 1.0 μl of clove oil for 30 min. Our results showed that the water-soluble protein content significantly decreased after the treatments, indicating that the metabolism of the mites was adversely affected. The bioactivity of GSTs increased significantly after a low dosage (0.1 μl exposure but decreased at a higher dosage (1.0 μl, while the activities of SOD and Ca2+-Mg2+-ATPase were significantly elevated after treatments. These results suggest that the protective enzyme SOD and detoxifying enzymes Ca2+-Mg2+-ATPase and GST contributed to the stress reaction of V. destructor to the essential oils and that the detoxification ability of V. destructor via GST was inhibited at higher dosages. Our findings are conducive to understanding the physiological reactions of V. destructor to treatment with essential oils and the underlying mechanisms behind the acaricidal activities of these natural products.

  18. Winter Survival of Individual Honey Bees and Honey Bee Colonies Depends on Level of Varroa destructor Infestation

    Science.gov (United States)

    van Dooremalen, Coby; Gerritsen, Lonne; Cornelissen, Bram; van der Steen, Jozef J. M.; van Langevelde, Frank; Blacquière, Tjeerd

    2012-01-01

    Background Recent elevated winter loss of honey bee colonies is a major concern. The presence of the mite Varroa destructor in colonies places an important pressure on bee health. V. destructor shortens the lifespan of individual bees, while long lifespan during winter is a primary requirement to survive until the next spring. We investigated in two subsequent years the effects of different levels of V. destructor infestation during the transition from short-lived summer bees to long-lived winter bees on the lifespan of individual bees and the survival of bee colonies during winter. Colonies treated earlier in the season to reduce V. destructor infestation during the development of winter bees were expected to have longer bee lifespan and higher colony survival after winter. Methodology/Principal Findings Mite infestation was reduced using acaricide treatments during different months (July, August, September, or not treated). We found that the number of capped brood cells decreased drastically between August and November, while at the same time, the lifespan of the bees (marked cohorts) increased indicating the transition to winter bees. Low V. destructor infestation levels before and during the transition to winter bees resulted in an increase in lifespan of bees and higher colony survival compared to colonies that were not treated and that had higher infestation levels. A variety of stress-related factors could have contributed to the variation in longevity and winter survival that we found between years. Conclusions/Significance This study contributes to theory about the multiple causes for the recent elevated colony losses in honey bees. Our study shows the correlation between long lifespan of winter bees and colony loss in spring. Moreover, we show that colonies treated earlier in the season had reduced V. destructor infestation during the development of winter bees resulting in longer bee lifespan and higher colony survival after winter. PMID:22558421

  19. Norwegian honey bees surviving Varroa destructor mite infestations by means of natural selection

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    Melissa A.Y. Oddie

    2017-10-01

    Full Text Available Background Managed, feral and wild populations of European honey bee subspecies, Apis mellifera, are currently facing severe colony losses globally. There is consensus that the ectoparasitic mite Varroa destructor, that switched hosts from the Eastern honey bee Apis cerana to the Western honey bee A. mellifera, is a key factor driving these losses. For >20 years, breeding efforts have not produced European honey bee colonies that can survive infestations without the need for mite control. However, at least three populations of European honey bees have developed this ability by means of natural selection and have been surviving for >10 years without mite treatments. Reduced mite reproductive success has been suggested as a key factor explaining this natural survival. Here, we report a managed A. mellifera population in Norway, that has been naturally surviving consistent V. destructor infestations for >17 years. Methods Surviving colonies and local susceptible controls were evaluated for mite infestation levels, mite reproductive success and two potential mechanisms explaining colony survival: grooming of adult worker bees and Varroa Sensitive Hygiene (VSH: adult workers specifically detecting and removing mite-infested brood. Results Mite infestation levels were significantly lower in surviving colonies and mite reproductive success was reduced by 30% when compared to the controls. No significant differences were found between surviving and control colonies for either grooming or VSH. Discussion Our data confirm that reduced mite reproductive success seems to be a key factor for natural survival of infested A. mellifera colonies. However, neither grooming nor VSH seem to explain colony survival. Instead, other behaviors of the adult bees seem to be sufficient to hinder mite reproductive success, because brood for this experiment was taken from susceptible donor colonies only. To mitigate the global impact of V. destructor, we suggest learning

  20. Norwegian honey bees surviving Varroa destructor mite infestations by means of natural selection.

    Science.gov (United States)

    Oddie, Melissa A Y; Dahle, Bjørn; Neumann, Peter

    2017-01-01

    Managed, feral and wild populations of European honey bee subspecies, Apis mellifera , are currently facing severe colony losses globally. There is consensus that the ectoparasitic mite Varroa destructor , that switched hosts from the Eastern honey bee Apis cerana to the Western honey bee A. mellifera , is a key factor driving these losses. For >20 years, breeding efforts have not produced European honey bee colonies that can survive infestations without the need for mite control. However, at least three populations of European honey bees have developed this ability by means of natural selection and have been surviving for >10 years without mite treatments. Reduced mite reproductive success has been suggested as a key factor explaining this natural survival. Here, we report a managed A. mellifera population in Norway, that has been naturally surviving consistent V. destructor infestations for >17 years. Surviving colonies and local susceptible controls were evaluated for mite infestation levels, mite reproductive success and two potential mechanisms explaining colony survival: grooming of adult worker bees and Varroa Sensitive Hygiene (VSH): adult workers specifically detecting and removing mite-infested brood. Mite infestation levels were significantly lower in surviving colonies and mite reproductive success was reduced by 30% when compared to the controls. No significant differences were found between surviving and control colonies for either grooming or VSH. Our data confirm that reduced mite reproductive success seems to be a key factor for natural survival of infested A. mellifera colonies. However, neither grooming nor VSH seem to explain colony survival. Instead, other behaviors of the adult bees seem to be sufficient to hinder mite reproductive success, because brood for this experiment was taken from susceptible donor colonies only. To mitigate the global impact of V. destructor , we suggest learning more from nature, i.e., identifying the obviously

  1. Varroa destructor resistance of honey bees in Hawaii, USA, that express various levels of Varroa sensitive hygiene (VSH)

    Science.gov (United States)

    The Big Island of Hawaii, USA, supports an important honey bee (Apis mellifera) queen rearing industry that has been threatened by Varroa destructor since 2008. Miticides widely used to manage mites are known to interfere with queen rearing and sperm production. We investigated whether bees bred for...

  2. Immunogene and viral transcript dynamics during parasitic Varroa destructor mite infection of developing honey bee (Apis mellifera) pupae.

    Science.gov (United States)

    Kuster, Ryan D; Boncristiani, Humberto F; Rueppell, Olav

    2014-05-15

    The ectoparasitic Varroa destructor mite is a major contributor to the ongoing honey bee health crisis. Varroa interacts with honey bee viruses, exacerbating their pathogenicity. In addition to vectoring viruses, immunosuppression of the developing honey bee hosts by Varroa has been proposed to explain the synergy between viruses and mites. However, the evidence for honey bee immune suppression by V. destructor is contentious. We systematically studied the quantitative effects of experimentally introduced V. destructor mites on immune gene expression at five specific time points during the development of the honey bee hosts. Mites reproduced normally and were associated with increased titers of deformed wing virus in the developing bees. Our data on different immune genes show little evidence for immunosuppression of honey bees by V. destructor. Experimental wounding of developing bees increases relative immune gene expression and deformed wing virus titers. Combined, these results suggest that mite feeding activity itself and not immunosuppression may contribute to the synergy between viruses and mites. However, our results also suggest that increased expression of honey bee immune genes decreases mite reproductive success, which may be explored to enhance mite control strategies. Finally, our expression data for multiple immune genes across developmental time and different experimental treatments indicates co-regulation of several of these genes and thus improves our understanding of the understudied honey bee immune system. © 2014. Published by The Company of Biologists Ltd.

  3. Interactive effect of reduced pollen availability and Varroa destructor infestation limits growth and protein content of young honey bees

    NARCIS (Netherlands)

    Dooremalen, van C.; Stam, E.; Gerritsen, L.J.M.; Cornelissen, B.; Steen, van der J.J.M.; Langevelde, van F.; Blacquiere, T.

    2013-01-01

    Varroa destructor in combination with one or more stressors, such as low food availability or chemical exposure, is considered to be one of the main causes for honey bee colony losses. We examined the inter-active effect of pollen availability on the protein content and body weight of young bees

  4. Varroa destructor virus 1: a new picorna-like virus in Varroa mites as well as honey bees

    NARCIS (Netherlands)

    Ongus, J.R.

    2006-01-01

    Varroa destructor mite is an ectoparasite of the honey bee Apis mellifera. This species was recently differentiated from Varroa jacobsoni species which infests the Asian bee Apis cerana. Varroa mites feed entirely on the bee's haemolymph and have been associated with the spread of a number of

  5. Queen survival and oxalic acid residues in sugar stores after summer application against Varroa destructor in honey bees (Apis mellifera)

    NARCIS (Netherlands)

    Cornelissen, B.; Donders, J.N.L.C.; Stratum, van P.; Blacquière, T.; Dooremalen, van C.

    2012-01-01

    Methods using oxalic acid (OA) to control Varroa destructor in honey bee (Apis mellifera) colonies are widely applied. In this study, the effects of an OA spray application in early summer on the survival of young and old queens, and on OA residues in sugar stores were investigated. A questionnaire

  6. LD50 and repellent effects of essential oils from Argentinian wild plant species on Varroa destructor.

    Science.gov (United States)

    Ruffinengo, Sergio; Eguaras, Martin; Floris, Ignazio; Faverin, Claudia; Bailac, Pedro; Ponzi, Marta

    2005-06-01

    The repellent and acaricidal effects of some essential oils from the most typical wild plant species of northern Patagonia, Argentina, on Varroa destructor Anderson & Trueman were evaluated using a complete exposure test. Honey bees, Apis mellifera L., and mites (five specimens of each per dish) were introduced in petri dishes having different oil concentrations (from 0.1 to 25 micro per cage). Survival of bees and mites was registered after 24, 48, and 72 h. An attraction/repellence test was performed using a wax tube impregnated with essential oil and another tube containing wax only. The lowest LD50 values for mites were registered for Acantholippia seriphioides (A. Gray) Mold. (1.27 microl per cage) and Schinus molle L. (2.65 microl per cage) after 24 h, and for Wedelia glauca (Ortega) O. Hoffm. ex Hicken (0.59 microl per cage) and A. seriphioides (1.09 microl per cage) after 72 h of treatment. The oil with the highest selectivity ratio (A. mellifera LD50/V. destructor LD50) was the one extracted from S. molle (>16). Oils of Lippia junelliana (Mold.) Troncoso, Minthostachys mollis (HBK) Grieseb., and Lippia turbinata Grieseb. mixed with wax had repellent properties. None of the oils tested had attractive effects on Varroa mites.

  7. Effects of Bacillus thuringiensis strains virulent to Varroa destructor on larvae and adults of Apis mellifera.

    Science.gov (United States)

    Alquisira-Ramírez, Eva Vianey; Peña-Chora, Guadalupe; Hernández-Velázquez, Víctor Manuel; Alvear-García, Andrés; Arenas-Sosa, Iván; Suarez-Rodríguez, Ramón

    2017-08-01

    The sublethal effects of two strains of Bacillus thuringiensis, which were virulent in vitro to Varroa destructor, were measured on Apis mellifera. The effects of five concentrations of total protein (1, 5, 25, 50 and 100μg/mL) from the EA3 and EA26.1 strains on larval and adult honey bees were evaluated for two and seven days under laboratory conditions. Based on the concentrations evaluated, total protein from the two strains did not affect the development of larvae, the syrup consumption, locomotor activity or proboscis extension response of adults. These same parameters were also tested for the effects of three concentrations (1, 10 and 15μg/kg) of cypermethrin as a positive control. Although no significant differences were observed after two days of treatment with cypermethrin, a dose-response relationship in syrup consumption and locomotor activity was observed. A significant reduction in the proboscis extension response of the bees treated with cypermethrin was also observed. Therefore, in contrast to cypermethrin, our results indicate that the EA3 and EA26.1 strains of B. thuringiensis can be used in beehives to control V. destructor and reduce the negative effects of this mite on colonies without adverse effects on the larvae and adults of A. mellifera. Additionally, the overuse of synthetic miticides, which produce both lethal and sublethal effects on bees, can be reduced. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. An amino acid substitution (L925V associated with resistance to pyrethroids in Varroa destructor.

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    Joel González-Cabrera

    Full Text Available The Varroa mite, Varroa destructor, is an important pest of honeybees and has played a prominent role in the decline in bee colony numbers over recent years. Although pyrethroids such as tau-fluvalinate and flumethrin can be highly effective in removing the mites from hives, their intensive use has led to many reports of resistance. To investigate the mechanism of resistance in UK Varroa samples, the transmembrane domain regions of the V. destructor voltage-gated sodium channel (the main target site for pyrethroids were PCR amplified and sequenced from pyrethroid treated/untreated mites collected at several locations in Central/Southern England. A novel amino acid substitution, L925V, was identified that maps to a known hot spot for resistance within the domain IIS5 helix of the channel protein; a region that has also been proposed to form part of the pyrethroid binding site. Using a high throughput diagnostic assay capable of detecting the mutation in individual mites, the L925V substitution was found to correlate well with resistance, being present in all mites that had survived tau-fluvalinate treatment but in only 8 % of control, untreated samples. The potential for using this assay to detect and manage resistance in Varroa-infected hives is discussed.

  9. Behavioral Modulation of Infestation by Varroa destructor in Bee Colonies. Implications for Colony Stability.

    Science.gov (United States)

    de Figueiró Santos, Joyce; Coelho, Flávio Codeço; Bliman, Pierre-Alexandre

    2016-01-01

    Colony Collapse Disorder (CCD) has become a global problem for beekeepers and for the crops that depend on bee pollination. While many factors are known to increase the risk of colony collapse, the ectoparasitic mite Varroa destructor is considered to be the most serious one. Although this mite is unlikely to cause the collapse of hives itself, it is the vector for many viral diseases which are among the likely causes for Colony Collapse Disorder. The effects of V. destructor infestation differ from one part of the world to another, with greater morbidity and higher colony losses in European honey bees (EHB) in Europe, Asia and North America. Although this mite has been present in Brazil for many years, there have been no reports of colony losses amongst Africanized Honey Bees (AHB). Studies carried out in Mexico have highlighted different behavioral responses by the AHB to the presence of the mite, notably as far as grooming and hygienic behavior are concerned. Could these explain why the AHB are less susceptible to Colony Collapse Disorder? In order to answer this question, we have developed a mathematical model of the infestation dynamics to analyze the role of resistance behavior by bees in the overall health of the colony, and as a consequence, its ability to face epidemiological challenges.

  10. Behavioral Modulation of Infestation by Varroa destructor in Bee Colonies. Implications for Colony Stability.

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    Joyce de Figueiró Santos

    Full Text Available Colony Collapse Disorder (CCD has become a global problem for beekeepers and for the crops that depend on bee pollination. While many factors are known to increase the risk of colony collapse, the ectoparasitic mite Varroa destructor is considered to be the most serious one. Although this mite is unlikely to cause the collapse of hives itself, it is the vector for many viral diseases which are among the likely causes for Colony Collapse Disorder. The effects of V. destructor infestation differ from one part of the world to another, with greater morbidity and higher colony losses in European honey bees (EHB in Europe, Asia and North America. Although this mite has been present in Brazil for many years, there have been no reports of colony losses amongst Africanized Honey Bees (AHB. Studies carried out in Mexico have highlighted different behavioral responses by the AHB to the presence of the mite, notably as far as grooming and hygienic behavior are concerned. Could these explain why the AHB are less susceptible to Colony Collapse Disorder? In order to answer this question, we have developed a mathematical model of the infestation dynamics to analyze the role of resistance behavior by bees in the overall health of the colony, and as a consequence, its ability to face epidemiological challenges.

  11. Éster de sacarose no controle do Varroa destructor em abelhas africanizadas = Sucrose ester in the control of Varroa destructor in Africanized honeybees

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    Guido Laércio Castagnino

    2009-07-01

    Full Text Available O presente trabalho teve como objetivo verificar o efeito do éster de sacarose no controle da infestação do ácaro Varroa destructor em abelhas africanizadas. Nos testes “in vitro”, testou-se o produto em abelhas e ácaros com cinco concentrações diluídas em água (T0: 100% de água destilada; T1: 0,5%; T2: 1%; T3: 2,0%; T4: 5% e T5: 10% de éster de sacarose. Nos testes de campo, o delineamento experimental utilizado foi inteiramente casualizado, com quatro tratamentos e sete repetições, totalizando 28 colônias, sendo sete delas como controle, sete com 0,1% de éster de sacarose, sete com 0,2% de éster de sacarosee sete colmeias com 0,5% éster de sacarose, diluídas em água. Nos testes “in vitro” com concentração de 0,5%, o éster de sacarose promoveu a mortalidade dos ácaros e das abelhas. Os testes em campo demonstraram que o produto reduziu a infestação do Varroa destructorem abelhas na concentração de 0,2% e pode ser uma ferramenta no controle dessa praga. Nas concentrações de 0,1; 0,2 e 0,5%, não prejudicou o desenvolvimento de área de cria aberta, operculada e de alimento estocado na colmeia, sugerindo que não é tóxico para as abelhas.This study aimed to determine the effect of sucrose ester on the control of Varroa destructor mite infestation in Africanized honeybees. For the in vitro experiments, the product was tested in bees and mites at five concentrations obtained through dilution in water (T0: 100% distilled water; T1: 0.5%; T2: 1%; T3: 2%; T4: 5%; and T5: 10% sucrose ester. For the field studies, the experimental design was completely randomized, with four treatments and seven replicates, totaling 28 colonies, from which seven were the controls,seven were treated with 0.1% sucrose ester, seven with 0.2% sucrose ester, and seven hives with 0.5% sucrose ester diluted in water. In the in vitro study, the sucrose ester at 0.5% concentration caused mite and bee mortality. In the field tests, the

  12. Varroa destructor mite in Africanized honeybee colonies Apis mellifera L. under royal jelly or honey production

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    Pedro da Rosa Santos

    2015-08-01

    Full Text Available This study evaluated the level of invasion of Varroa mite into worker brood cells, the infestation rate on adult worker honeybees, total and effective reproduction rates of the mite in Africanized honeybee colonies under royal jelly or honey production. Invasion and infestation rates were not statistically different between honeybee colonies producing honey or royal jelly and the averages for these parameters were 5.79 and 8.54%, respectively. Colonies producing honey presented a higher (p < 0.05 total and effective reproduction of Varroa than colonies producing royal jelly. There was a negative correlation between levels of invasion and infestation with minimum external temperature, relative humidity and rainfall. The variables month and season influenced the development of the mite, but rates were low and within the range normally found in Brazil for Africanized honeybee colonies, which confirm the greater resistance of these honeybees to Varroa destructor than European honeybees.

  13. Infestation and distribution of the mite Varroa destructor in colonies of africanized bees

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    G. Moretto

    Full Text Available Whereas in several parts of the world varroa is the major pest affecting apiculture, in others the parasite is unknown to many beekeepers because its damage to bees is minor. The impact of the mite Varroa destructor is related to the climatic conditions and the races of Apis mellifera bees in each region where the pest exists. In the present study, the current level of infestation by the mite was assessed to determine the evolution of the pest in Africanized bee colonies in Southern Brazil. This level of infestation was considered low: approximately two mites per one hundred adult bees. This result is similar to that obtained for the same apiary almost five years ago and for others distributed in various regions of Brazil. In the present study, we also estimated the total varroa population and its distribution among brood and adults in each bee colony.

  14. Primary structure of Lep d I, the main Lepidoglyphus destructor allergen.

    Science.gov (United States)

    Varela, J; Ventas, P; Carreira, J; Barbas, J A; Gimenez-Gallego, G; Polo, F

    1994-10-01

    The most relevant allergen of the storage mite Lepidoglyphus destructor (Lep d I) has been characterized. Lep d I is a monomer protein of 13273 Da. The primary structure of Lep d I was determined by N-terminal Edman degradation and partially confirmed by cDNA sequencing. Sequence polymorphism was observed at six positions, with non-conservative substitutions in three of them. No potential N-glycosylation site was revealed by peptide sequencing. The 125-residue sequence of Lep d I shows approximately 40% identity (including the six cysteines) with the overlapping regions of group II allergens from the genus Dermatophagoides, which, however, do not share common allergenic epitopes with Lep d I.

  15. Produtos naturais para o controle do ácaro Varroa destructor em abelhas africanizadas

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    Guido Laércio Bragança Castagnino

    2012-06-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos do ácido oxálico e de óleos essenciais de plantas no controle da infestação pelo ácaro Varroa destructor em colônias de Apis mellifera africanizadas. O experimento foi realizado em delineamento inteiramente casualizado, em 30 colônias, com seis tratamentos e cinco repetições. As colmeias foram tratadas com óleos essenciais de arruda (Ruta graveolens, eucalipto (Eucalyptus spp. e hortelã (Mentha piperita, além de timol, ácido oxálico e do tratamento controle sem aplicação de produtos. Foram avaliadas a mortalidade de varroas e as taxas de mortalidade de crias e de infestação de varroas em crias e em abelhas adultas, antes e depois da aplicação de cada produto. O ácido oxálico e os óleos de arruda, timol, eucalipto e de hortelã reduziram a mortalidade de crias parasitadas pelo ácaro em 92,1, 83,3, 81,7, 86,4 e 81,3%, respectivamente. O tratamento com ácido oxálico reduziu em 87,4% a infestação de varroas em abelhas adultas. O uso desses produtos é eficiente na redução da mortalidade de crias de A. mellifera parasitadas por V. destructor.

  16. Biological Activity of the Salvia officinalis L. (Lamiaceae Essential Oil on Varroa destructor Infested Honeybees

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    Leila Bendifallah

    2018-06-01

    Full Text Available The present work is conducted as part of the development and the valorization of bioactive natural substances from Algerian medicinal and aromatic spontaneous plants, a clean alternative method in biological control. For this purpose, the bio-acaricidal activity of Salvia officinalis (sageessential oil (EOwas evaluated against the Varroa destructor, a major threat to the honey bee Apis mellifera ssp. intermissa. The aerial parts of S. officinalis L., 1753 were collected from the Chrea mountainous area in Northern Algeria. They were subjected to hydro distillation by a Clevenger apparatus type to obtain the EO, and screened for bio-acaricidal activity against Varroa destructor by the method of strips impregnated with the mixture EO and twin according to three doses. Pre-treatment results revealed infestation rates in the experimental site ranging from 3.76% to 21.22%. This showed the heterogeneity of infestations in hives according to the density of bees. This constituted a difficulty in monitoring the population dynamics of this parasite. After treatment, a difference in the acaricidal effect of Sage essential oil is noticed. It gives a mortality rate of 6.09% by the dose D1: 5%, 2.32% by the dose D2: 15%, and a low mortality rate of 0.9% by the dose D3: 20%. The chemical treatment carried out by Bayvarol gives a result close to that of the essential oil of Sage (9.97%.These results point to the fact that Sage essential oil treatments have a significant effect and good biological activity with regard to harmful species.

  17. Viral epidemiology of the adult Apis Mellifera infested by the Varroa destructor mite.

    Science.gov (United States)

    Bernardi, Sara; Venturino, Ezio

    2016-05-01

    The ectoparasitic mite Varroa destructor has become one of the major worldwide threats for apiculture. Varroa destructor attacks the honey bee Apis mellifera weakening its host by sucking hemolymph. However, the damage to bee colonies is not strictly related to the parasitic action of the mite but it derives, above all, from its action as vector increasing the transmission of many viral diseases such as acute paralysis (ABPV) and deformed wing viruses (DWV), that are considered among the main causes of CCD (Colony Collapse Disorder). In this work we discuss an [Formula: see text] model that describes how the presence of the mite affects the epidemiology of these viruses on adult bees. The acronym [Formula: see text] means that the disease affects both populations. In fact it accounts for the bee and mite populations, that are each divided among the S (susceptible) and I (infected) states. We characterize the system behavior, establishing that ultimately either only healthy bees survive, or the disease becomes endemic and mites are wiped out. Another dangerous alternative is the Varroa invasion scenario with the extinction of healthy bees. The final possible configuration is the coexistence equilibrium in which honey bees share their infected hive with mites. The analysis is in line with some observed facts in natural honey bee colonies. Namely, these diseases are endemic. Further, if the mite population is present, necessarily the viral infection occurs. The findings of this study indicate that a low horizontal transmission rate of the virus among honey bees in beehives will help in protecting bee colonies from Varroa infestation and viral epidemics.

  18. Sélection d'abeilles résistantes à Varroa destructor en Amérique du Nord.

    OpenAIRE

    Rinderer , Thomas E.; Harris , Jeffrey W.; Hunt , Gregory J.; De Guzman , Lilia I.

    2010-01-01

    International audience; Breeding for resistance to Varroa destructor in North America provides the long-term solution to the economic troubles the mite brings. This review reports the development of two breeding successes that have produced honey bees of commercial quality that do not require pesticide treatment to control Varroa, highlights other traits that could be combined to increase resistance and examines the potential uses of marker-assisted selection (MAS) for breeding for Varroa res...

  19. Expression of the Prophenoloxidase Gene and Phenoloxidase Activity, During the Development of Apis Mellifera Brood Infected with Varroa Destructor

    OpenAIRE

    Zaobidna Ewa A.; Żółtowska Krystyna; Łopieńska-Biernat Elżbieta

    2015-01-01

    The pathogenesis of varroasis has not been fully explained despite intensive research. Earlier studies suggested that parasitic infections caused by Varroa destructor mites were accompanied by immunosuppression in the host organism. The objective of this study was to analyse the influence of varroasis on one of the immune pathway in Apis mellifera measured by the expression of the prophenoloxidase (proPO) gene and the enzymatic activity of this gene’s product, phenoloxidase (EC 1.14.18.1). An...

  20. Novel Mutations in the Voltage-Gated Sodium Channel of Pyrethroid-Resistant Varroa destructor Populations from the Southeastern USA.

    Science.gov (United States)

    González-Cabrera, Joel; Rodríguez-Vargas, Sonia; Davies, T G Emyr; Field, Linda M; Schmehl, Daniel; Ellis, James D; Krieger, Klemens; Williamson, Martin S

    2016-01-01

    The parasitic mite Varroa destructor has a significant worldwide impact on bee colony health. In the absence of control measures, parasitized colonies invariably collapse within 3 years. The synthetic pyrethroids tau-fluvalinate and flumethrin have proven very effective at managing this mite within apiaries, but intensive control programs based mainly on one active ingredient have led to many reports of pyrethroid resistance. In Europe, a modification of leucine to valine at position 925 (L925V) of the V. destructor voltage-gated sodium channel was correlated with resistance, the mutation being found at high frequency exclusively in hives with a recent history of pyrethroid treatment. Here, we identify two novel mutations, L925M and L925I, in tau-fluvalinate resistant V. destructor collected at seven sites across Florida and Georgia in the Southeastern region of the USA. Using a multiplexed TaqMan® allelic discrimination assay, these mutations were found to be present in 98% of the mites surviving tau-fluvalinate treatment. The mutations were also found in 45% of the non-treated mites, suggesting a high potential for resistance evolution if selection pressure is applied. The results from a more extensive monitoring programme, using the Taqman® assay described here, would clearly help beekeepers with their decision making as to when to include or exclude pyrethroid control products and thereby facilitate more effective mite management programmes.

  1. Novel Mutations in the Voltage-Gated Sodium Channel of Pyrethroid-Resistant Varroa destructor Populations from the Southeastern USA.

    Directory of Open Access Journals (Sweden)

    Joel González-Cabrera

    Full Text Available The parasitic mite Varroa destructor has a significant worldwide impact on bee colony health. In the absence of control measures, parasitized colonies invariably collapse within 3 years. The synthetic pyrethroids tau-fluvalinate and flumethrin have proven very effective at managing this mite within apiaries, but intensive control programs based mainly on one active ingredient have led to many reports of pyrethroid resistance. In Europe, a modification of leucine to valine at position 925 (L925V of the V. destructor voltage-gated sodium channel was correlated with resistance, the mutation being found at high frequency exclusively in hives with a recent history of pyrethroid treatment. Here, we identify two novel mutations, L925M and L925I, in tau-fluvalinate resistant V. destructor collected at seven sites across Florida and Georgia in the Southeastern region of the USA. Using a multiplexed TaqMan® allelic discrimination assay, these mutations were found to be present in 98% of the mites surviving tau-fluvalinate treatment. The mutations were also found in 45% of the non-treated mites, suggesting a high potential for resistance evolution if selection pressure is applied. The results from a more extensive monitoring programme, using the Taqman® assay described here, would clearly help beekeepers with their decision making as to when to include or exclude pyrethroid control products and thereby facilitate more effective mite management programmes.

  2. Novel Mutations in the Voltage-Gated Sodium Channel of Pyrethroid-Resistant Varroa destructor Populations from the Southeastern USA

    Science.gov (United States)

    González-Cabrera, Joel; Rodríguez-Vargas, Sonia; Davies, T. G. Emyr; Field, Linda M.; Schmehl, Daniel; Ellis, James D.; Krieger, Klemens; Williamson, Martin S.

    2016-01-01

    The parasitic mite Varroa destructor has a significant worldwide impact on bee colony health. In the absence of control measures, parasitized colonies invariably collapse within 3 years. The synthetic pyrethroids tau-fluvalinate and flumethrin have proven very effective at managing this mite within apiaries, but intensive control programs based mainly on one active ingredient have led to many reports of pyrethroid resistance. In Europe, a modification of leucine to valine at position 925 (L925V) of the V. destructor voltage-gated sodium channel was correlated with resistance, the mutation being found at high frequency exclusively in hives with a recent history of pyrethroid treatment. Here, we identify two novel mutations, L925M and L925I, in tau-fluvalinate resistant V. destructor collected at seven sites across Florida and Georgia in the Southeastern region of the USA. Using a multiplexed TaqMan® allelic discrimination assay, these mutations were found to be present in 98% of the mites surviving tau-fluvalinate treatment. The mutations were also found in 45% of the non-treated mites, suggesting a high potential for resistance evolution if selection pressure is applied. The results from a more extensive monitoring programme, using the Taqman® assay described here, would clearly help beekeepers with their decision making as to when to include or exclude pyrethroid control products and thereby facilitate more effective mite management programmes. PMID:27191597

  3. Identification and gene-silencing of a putative odorant receptor transcription factor in Varroa destructor: possible role in olfaction.

    Science.gov (United States)

    Singh, N K; Eliash, N; Stein, I; Kamer, Y; Ilia, Z; Rafaeli, A; Soroker, V

    2016-04-01

    The ectoparasitic mite Varroa destructor is one of the major threats to apiculture. Using a behavioural choice bioassay, we determined that phoretic mites were more successful in reaching a bee than reproductive mites, suggesting an energy trade-off between reproduction and host selection. We used both chemo-ecological and molecular strategies to identify the regulation of the olfactory machinery of Varroa and its association with reproduction. We focused on transcription regulation. Using primers designed to the conserved DNA binding region of transcription factors, we identified a gene transcript in V. destructor homologous to the pheromone receptor transcription factor (PRTF) gene of Pediculus humanus corporis. Quantitative PCR (qPCR) revealed that this PRTF-like gene transcript is expressed in the forelegs at higher levels than in the body devoid of forelegs. Subsequent comparative qPCR analysis showed that transcript expression was significantly higher in the phoretic as compared to the reproductive stage. Electrophysiological and behavioural studies revealed a reduction in the sensitivity of PRTF RNA interference-silenced mites to bee headspace, consistent with a reduction in the mites' ability to reach a host. In addition, vitellogenin expression was stimulated in PRTF-silenced mites to similar levels as found in reproductive mites. These data shed light upon the regulatory mechanism of host chemosensing in V. destructor. © 2016 The Royal Entomological Society.

  4. Frequency of Varroa destructor, Nosema spp and Acarapis woodi in commercial colonies of bees (Apis mellifera in Yucatan, Mexico

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    Martínez-Puc Jesús Froylán

    2015-10-01

    Full Text Available Today it has been observed that diseases affecting bees (Apis mellifera have caused significant economic losses in the European continent and in parts of the United States due to high mortality in honey bee colonies without a cause apparent, which is known as the syndrome of depopulation of hives. It is noteworthy that this mortality is not yet presented in Yucatan. In order to determine the frequency and levels of infestation Acarapis woodi and Varroa destructor, and the frequency and levels of infection Nosema spp. commercial colonies of bees (A. mellifera in Yucatan, was collected from June to December 2006, a total of 165 samples distributed in 13 towns of Yucatan. V. destructor frequency was 63.6%, with an average level of infestation of 2.85 ± 0.79 (mites / 100 bees. The frequency of Nosema spp. was 81.8%, with an average infection level = 1'234000 ± 118000 (spores / bee, the presence of A. woodi in the samples analyzed was detected. The existence of an association between V. destructor and Nosema spp was observed. (X2 = 6.53, df = 1, p = 0.01.

  5. Drone Use in Monioring Open Ocean Surface Debris, Including Paired Manta and Tucker Trawls for Relateing Sea State to Vertical Debris Distribution

    Science.gov (United States)

    Lattin, G.

    2016-02-01

    Monitoring debris at sea presents challenges not found in beach or riverine habitats, and is typically done with trawl nets of various apertures and mesh sizes, which limits the size of debris captured and the area surveyed. To partially overcome these limitations in monitoring floating debris, a Quadcopter drone with video transmitting and recording capabilities was deployed at the beginning and the end of manta trawl transects within the North Pacific Subtropical Gyre's eastern convergence zone. Subsurface tucker trawls at 10 meters were conducted at the same time as the manta trawls, in order to assess the effect of sea state on debris dispersal. Trawls were conducted on an 11 station grid used repeatedly since 1999. For drone observations, the operator and observer were stationed on the mother ship while two researchers collected observed debris using a rigid inflatable boat (RIB). The drone was flown to a distance of approximately 100 meters from the vessel in a zigzag or circular search pattern. Here we examine issues arising from drone deployment during the survey: 1) relation of area surveyed by drone to volume of water passing through trawl; 2) retrieval of drone-spotted and associated RIB spotted debris. 3) integrating post- flight image analysis into retrieved debris quantification; and 4) factors limiting drone effectiveness at sea. During the survey, debris too large for the manta trawl was spotted by the drone, and significant debris not observed using the drone was recovered by the RIB. The combination of drone sightings, RIB retrieval, and post flight image analysis leads to improved monitoring of debris at sea. We also examine the issue of the distribution of floating debris during sea states varying from 0-5 by comparing quantities from surface manta trawls to the tucker trawls at a nominal depth of 10 meters.

  6. Evaluating the Effects of Differences in Group Abilities on the Tucker and the Levine Observed-Score Methods for Common-Item Nonequivalent Groups Equating. ACT Research Report Series 2010-1

    Science.gov (United States)

    Chen, Hanwei; Cui, Zhongmin; Zhu, Rongchun; Gao, Xiaohong

    2010-01-01

    The most critical feature of a common-item nonequivalent groups equating design is that the average score difference between the new and old groups can be accurately decomposed into a group ability difference and a form difficulty difference. Two widely used observed-score linear equating methods, the Tucker and the Levine observed-score methods,…

  7. Risk factors associated with the presence of Varroa destructor in honey bee colonies from east-central Argentina.

    Science.gov (United States)

    Giacobino, A; Bulacio Cagnolo, N; Merke, J; Orellano, E; Bertozzi, E; Masciangelo, G; Pietronave, H; Salto, C; Signorini, M

    2014-08-01

    Varroa destructor is considered one of the major threats for worldwide apiculture. Damage caused by varroa mite includes body weight loss, malformation and weakening of the bees. It was also suggested as the main cause associated with colony winter mortality and as an important vector for several honey bee viruses. Little is known about multiple factors and their interaction affecting V. destructor prevalence in apiaries from South America. The aim of this study was to identify risk factors associated with V. destructor prevalence in east-central Argentina. Parasitic mite infestation level and colony strength measures were evaluated in 63 apiaries distributed in 4 different regions in east-central Argentina in a cross sectional study. Data regarding management practices in each apiary were collected by means of a questionnaire. A mixed-effects logistic regression model was constructed to associate management variables with the risk of achieving mite infestation higher than 3%. Colonies owned by beekeepers who indicated that they did not monitor colonies after mite treatment (OR=2.305; 95% CI: 0.944-5.629) nor disinfect hives woodenware material (OR=2.722; 95% CI: 1.380-5.565) were associated with an increased risk of presenting high intensity infestation with V. destructor (>3%). On the other hand, beekeepers who reported replacing more than 50% of the queens in their operation (OR=0.305; 95% CI: 0.107-0.872), feeding colonies protein substitute containing natural pollen (OR=0.348; 95% CI: 0.129-0.941) and feeding colonies High Fructose Corn Syrup (HFCS) (OR=0.108; 95% CI: 0.032-0.364), had colonies that were less likely to have V. destructor infestations above 3%, than beekeepers who did not report using these management practices. Further research should be conducted considering that certain management practices were associated to mite infestation level in order to improve the sanitary condition in the colonies. Epidemiological studies provide key information to

  8. Differential expression of candidate salivary effector proteins in field collections of Hessian fly, Mayetiola destructor

    Science.gov (United States)

    Johnson, A J; Shukle, R H; Chen, M-S; Srivastava, S; Subramanyam, S; Schemerhorn, B J; Weintraub, P G; Abdel Moniem, H E M; Flanders, K L; Buntin, G D; Williams, C E

    2015-01-01

    Evidence is emerging that some proteins secreted by gall-forming parasites of plants act as effectors responsible for systemic changes in the host plant, such as galling and nutrient tissue formation. A large number of secreted salivary gland proteins (SSGPs) that are the putative effectors responsible for the physiological changes elicited in susceptible seedling wheat by Hessian fly, Mayetiola destructor (Say), larvae have been documented. However, how the genes encoding these candidate effectors might respond under field conditions is unknown. The goal of this study was to use microarray analysis to investigate variation in SSGP transcript abundance amongst field collections from different geographical regions (southeastern USA, central USA, and the Middle East). Results revealed significant variation in SSGP transcript abundance amongst the field collections studied. The field collections separated into three distinct groups that corresponded to the wheat classes grown in the different geographical regions as well as to recently described Hessian fly populations. These data support previous reports correlating Hessian fly population structure with micropopulation differences owing to agro-ecosystem parameters such as cultivation of regionally adapted wheat varieties, deployment of resistance genes and variation in climatic conditions. PMID:25528896

  9. Selection of Apis mellifera workers by the parasitic mite Varroa destructor using host cuticular hydrocarbons.

    Science.gov (United States)

    Del Piccolo, F; Nazzi, F; Della Vedova, G; Milani, N

    2010-05-01

    The parasitic mite, Varroa destructor, is the most important threat for apiculture in most bee-keeping areas of the world. The mite is carried to the bee brood cell, where it reproduces, by a nurse bee; therefore the selection of the bee stage by the parasite could influence its reproductive success. This study investigates the role of the cuticular hydrocarbons of the European honeybee (Apis mellifera) in host-selection by the mite. Preliminary laboratory bioassays confirmed the preference of the varroa mite for nurse bees over pollen foragers. GC-MS analysis of nurse and pollen bees revealed differences in the cuticular hydrocarbons of the two stages; in particular, it appeared that pollen bees have more (Z)-8-heptadecene than nurse bees. Laboratory experiments showed that treatment of nurse bees with 100 ng of the pure compound makes them repellent to the varroa mite. These results suggest that the mite can exploit the differences in the cuticular composition of its host for a refined selection that allows it to reach a brood cell and start reproduction. The biological activity of the alkene encourages further investigations for the development of novel control techniques based on this compound.

  10. Can we disrupt the sensing of honey bees by the bee parasite Varroa destructor?

    Science.gov (United States)

    Eliash, Nurit; Singh, Nitin Kumar; Kamer, Yosef; Pinnelli, Govardhana Reddy; Plettner, Erika; Soroker, Victoria

    2014-01-01

    The ectoparasitic mite, Varroa destructor, is considered to be one of the most significant threats to apiculture around the world. Chemical cues are known to play a significant role in the host-finding behavior of Varroa. The mites distinguish between bees from different task groups, and prefer nurses over foragers. We examined the possibility of disrupting the Varroa--honey bee interaction by targeting the mite's olfactory system. In particular, we examined the effect of volatile compounds, ethers of cis 5-(2'-hydroxyethyl) cyclopent-2-en-1-ol or of dihydroquinone, resorcinol or catechol. We tested the effect of these compounds on the Varroa chemosensory organ by electrophysiology and on behavior in a choice bioassay. The electrophysiological studies were conducted on the isolated foreleg. In the behavioral bioassay, the mite's preference between a nurse and a forager bee was evaluated. We found that in the presence of some compounds, the response of the Varroa chemosensory organ to honey bee headspace volatiles significantly decreased. This effect was dose dependent and, for some of the compounds, long lasting (>1 min). Furthermore, disruption of the Varroa volatile detection was accompanied by a reversal of the mite's preference from a nurse to a forager bee. Long-term inhibition of the electrophysiological responses of mites to the tested compounds was a good predictor for an alteration in the mite's host preference. These data indicate the potential of the selected compounds to disrupt the Varroa--honey bee associations, thus opening new avenues for Varroa control.

  11. Control of Varroa Mite (Varroa destructor on Honeybees by Aromatic Oils and Plant Materials

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    I.K. Nazer

    2003-01-01

    Full Text Available The effect of several volatile plant oils, plant materials and fluvalinate (Apistan® strips on the control of the mite Varroa destructor on honeybee (Apis mellifera L. colonies was studied. The volatile oils were: clove, lavender, peppermint, sage, and thyme. The plant materials were: cumin fruits, eucalyptus leaves, and worm wood flowers. For each tested material, three treatment periods were carried out. Each period lasted for 24 days followed by eight days no-treatment. Within each treatment period, an average of three to six treatments were applied. Dead mites were counted one hour before and after each treatment. An increase in dead mites was recorded for the three treatment periods. It indicated that worm wood flowers, peppermint oil and clove oil treatments gave the best results in the control of Varroa mites but not significantly different than the control. The overall increase in the dead mites was 3.92, 3.62 and 3.34 fold, respectively.

  12. Genomic survey of the ectoparasitic mite Varroa destructor, a major pest of the honey bee Apis mellifera

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    Elsik Chris

    2010-10-01

    Full Text Available Abstract Background The ectoparasitic mite Varroa destructor has emerged as the primary pest of domestic honey bees (Apis mellifera. Here we present an initial survey of the V. destructor genome carried out to advance our understanding of Varroa biology and to identify new avenues for mite control. This sequence survey provides immediate resources for molecular and population-genetic analyses of Varroa-Apis interactions and defines the challenges ahead for a comprehensive Varroa genome project. Results The genome size was estimated by flow cytometry to be 565 Mbp, larger than most sequenced insects but modest relative to some other Acari. Genomic DNA pooled from ~1,000 mites was sequenced to 4.3× coverage with 454 pyrosequencing. The 2.4 Gbp of sequencing reads were assembled into 184,094 contigs with an N50 of 2,262 bp, totaling 294 Mbp of sequence after filtering. Genic sequences with homology to other eukaryotic genomes were identified on 13,031 of these contigs, totaling 31.3 Mbp. Alignment of protein sequence blocks conserved among V. destructor and four other arthropod genomes indicated a higher level of sequence divergence within this mite lineage relative to the tick Ixodes scapularis. A number of microbes potentially associated with V. destructor were identified in the sequence survey, including ~300 Kbp of sequence deriving from one or more bacterial species of the Actinomycetales. The presence of this bacterium was confirmed in individual mites by PCR assay, but varied significantly by age and sex of mites. Fragments of a novel virus related to the Baculoviridae were also identified in the survey. The rate of single nucleotide polymorphisms (SNPs in the pooled mites was estimated to be 6.2 × 10-5per bp, a low rate consistent with the historical demography and life history of the species. Conclusions This survey has provided general tools for the research community and novel directions for investigating the biology and control of

  13. Effects of Imidacloprid and Varroa destructor on survival and health of European honey bees, Apis mellifera.

    Science.gov (United States)

    Abbo, Pendo M; Kawasaki, Joshua K; Hamilton, Michele; Cook, Steven C; DeGrandi-Hoffman, Gloria; Li, Wen Feng; Liu, Jie; Chen, Yan Ping

    2017-06-01

    There has been growing concern over declines in populations of honey bees and other pollinators which are a vital part to our food security. It is imperative to identify factors responsible for accelerated declines in bee populations and develop solutions for reversing bee losses. While exact causes of colony losses remain elusive, risk factors thought to play key roles are ectoparasitic mites Varroa destructor and neonicotinoid pesticides. The present study aims to investigate effects of a neonicotinoid pesticide Imidacloprid and Varroa mites individually on survivorship, growth, physiology, virus dynamics and immunity of honey bee workers. Our study provides clear evidence that the exposure to sublethal doses of Imidacloprid could exert a significantly negative effect on health and survival of honey bees. We observed a significant reduction in the titer of vitellogenin (Vg), an egg yolk precursor that regulates the honey bees development and behavior and often are linked to energy homeostasis, in bees exposed to Imidacloprid. This result indicates that sublethal exposure to neonicotinoid could lead to increased energy usage in honey bees as detoxification is a energy-consuming metabolic process and suggests that Vg could be a useful biomarker for measuring levels of energy stress and sublethal effects of pesticides on honey bees. Measurement of the quantitative effects of different levels of Varroa mite infestation on the replication dynamic of Deformed wing virus (DWV), an RNA virus associated with Varroa infestation, and expression level of immune genes yields unique insights into how honey bees respond to stressors under laboratory conditions. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  14. Emissions from the burning of vegetative debris in air curtain destructors.

    Science.gov (United States)

    Miller, C Andrew; Lemieux, Paul M

    2007-08-01

    Although air curtain destructors (ACDs) have been used for quite some time to dispose of vegetative debris, relatively little in-depth testing has been conducted to quantify emissions of pollutants other than CO and particulate matter. As part of an effort to prepare for possible use of ACDs to dispose of the enormous volumes of debris generated by Hurricanes Katrina and Rita, the literature on ACD emissions was reviewed to identify potential environmental issues associated with ACD disposal of construction and demolition (C&D) debris. Although no data have been published on emissions from C&D debris combustion in an ACD, a few studies provided information on emissions from the combustion of vegetative debris. These studies are reviewed, and the results compared with studies of open burning of biomass. Combustion of vegetative debris in ACD units results in significantly lower emissions of particulate matter and CO per unit of mass of debris compared with open pile burning. The available data are not sufficient to make general estimates regarding emissions of organic or metal compounds. The highly transient nature of the ACD combustion process, a minimal degree of operational control, and significant variability in debris properties make accurate prediction of ACD emissions impossible in general. Results of scoping tests conducted in preparation for possible in-depth emissions tests demonstrate the challenges associated with sampling ACD emissions and highlight the transient nature of the process. The environmental impacts of widespread use of ACDs for disposal of vegetative debris and their potential use to reduce the volume of C&D debris in future disaster response scenarios remain a considerable gap in understanding the risks associated with debris disposal options.

  15. Effects of Imidacloprid and Varroa destructor on survival and health of European honey bees, Apis mellifera

    Institute of Scientific and Technical Information of China (English)

    Pendo M.Abbo; Joshua K.Kawasaki; Michele Hamilton; Steven C.Cook; Gloria DeGrandi-Hoffman; Wen Feng Li; Jie Liu; Yan Ping Chen

    2017-01-01

    There has been growing concern over declines in populations of honey bees and other pollinators which are a vital part to our food security.It is imperative to identify factors responsible for accelerated declines in bee populations and develop solutions for reversing bee losses.While exact causes of colony losses remain elusive,risk factors thought to play key roles are ectoparasitic mites Varroa destructor and neonicotinoid pesticides.The present study aims to investigate effects of a neonicotinoid pesticide Imidacloprid and Varroa mites individually on survivorship,growth,physiology,virus dynamics and immunity of honey bee workers.Our study provides clear evidence that the exposure to sublethal doses of Imidacloprid could exert a significantly negative effect on health and survival of honey bees.We observed a significant reduction in the titer ofvitellogenin (Vg),an egg yolk precursor that regulates the honey bees development and behavior and often are linked to energy homeostasis,in bees exposed to Imidacloprid.This result indicates that sublethal exposure to neonicotinoid could lead to increased energy usage in honey bees as detoxification is a energy-consuming metabolic process and suggests that Vg could be a useful biomarker for measuring levels of energy stress and sublethal effects of pesticideson honey bees.Measurement of the quantitative effects of different levels of Varroa mite infestation on the replication dynamic of Deformed wing virus (DWV),an RNA virus associated with Varroa infestation,and expression level of immune genes yields unique insights into how honey bees respond to stressors under laboratory conditions.

  16. A selective sweep in a Varroa destructor resistant honeybee (Apis mellifera) population.

    Science.gov (United States)

    Lattorff, H Michael G; Buchholz, Josephine; Fries, Ingemar; Moritz, Robin F A

    2015-04-01

    The mite Varroa destructor is one of the most dangerous parasites of the Western honeybee (Apis mellifera) causing enormous colony losses worldwide. Various chemical treatments for the control of the Varroa mite are currently in use, which, however, lead to residues in bee products and often to resistance in mites. This facilitated the exploration of alternative treatment methods and breeding for mite resistant honeybees has been in focus for breeders in many parts of the world with variable results. Another approach has been applied to a honeybee population on Gotland (Sweden) that was exposed to natural selection and survived Varroa-infestation for more than 10years without treatment. Eventually this population became resistant to the parasite by suppressing the reproduction of the mite. A previous QTL mapping study had identified a region on chromosome 7 with major loci contributing to the mite resistance. Here, a microsatellite scan of the significant candidate QTL regions was used to investigate potential footprints of selection in the original population by comparing the study population on Gotland before (2000) and after selection (2007). Genetic drift had caused an extreme loss of genetic diversity in the 2007 population for all genetic markers tested. In addition to this overall reduction of heterozygosity, two loci on chromosome 7 showed an even stronger and significant reduction in diversity than expected from genetic drift alone. Within the selective sweep eleven genes are annotated, one of them being a putative candidate to interfere with reduced mite reproduction. A glucose-methanol-choline oxidoreductase (GMCOX18) might be involved in changing volatiles emitted by bee larvae that might be essential to trigger oogenesis in Varroa. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Can We Disrupt the Sensing of Honey Bees by the Bee Parasite Varroa destructor?

    Science.gov (United States)

    Eliash, Nurit; Singh, Nitin Kumar; Kamer, Yosef; Pinnelli, Govardhana Reddy; Plettner, Erika; Soroker, Victoria

    2014-01-01

    Background The ectoparasitic mite, Varroa destructor, is considered to be one of the most significant threats to apiculture around the world. Chemical cues are known to play a significant role in the host-finding behavior of Varroa. The mites distinguish between bees from different task groups, and prefer nurses over foragers. We examined the possibility of disrupting the Varroa – honey bee interaction by targeting the mite's olfactory system. In particular, we examined the effect of volatile compounds, ethers of cis 5-(2′-hydroxyethyl) cyclopent-2-en-1-ol or of dihydroquinone, resorcinol or catechol. We tested the effect of these compounds on the Varroa chemosensory organ by electrophysiology and on behavior in a choice bioassay. The electrophysiological studies were conducted on the isolated foreleg. In the behavioral bioassay, the mite's preference between a nurse and a forager bee was evaluated. Principal findings We found that in the presence of some compounds, the response of the Varroa chemosensory organ to honey bee headspace volatiles significantly decreased. This effect was dose dependent and, for some of the compounds, long lasting (>1 min). Furthermore, disruption of the Varroa volatile detection was accompanied by a reversal of the mite's preference from a nurse to a forager bee. Long-term inhibition of the electrophysiological responses of mites to the tested compounds was a good predictor for an alteration in the mite's host preference. Conclusions These data indicate the potential of the selected compounds to disrupt the Varroa - honey bee associations, thus opening new avenues for Varroa control. PMID:25226388

  18. Can we disrupt the sensing of honey bees by the bee parasite Varroa destructor?

    Directory of Open Access Journals (Sweden)

    Nurit Eliash

    Full Text Available BACKGROUND: The ectoparasitic mite, Varroa destructor, is considered to be one of the most significant threats to apiculture around the world. Chemical cues are known to play a significant role in the host-finding behavior of Varroa. The mites distinguish between bees from different task groups, and prefer nurses over foragers. We examined the possibility of disrupting the Varroa--honey bee interaction by targeting the mite's olfactory system. In particular, we examined the effect of volatile compounds, ethers of cis 5-(2'-hydroxyethyl cyclopent-2-en-1-ol or of dihydroquinone, resorcinol or catechol. We tested the effect of these compounds on the Varroa chemosensory organ by electrophysiology and on behavior in a choice bioassay. The electrophysiological studies were conducted on the isolated foreleg. In the behavioral bioassay, the mite's preference between a nurse and a forager bee was evaluated. PRINCIPAL FINDINGS: We found that in the presence of some compounds, the response of the Varroa chemosensory organ to honey bee headspace volatiles significantly decreased. This effect was dose dependent and, for some of the compounds, long lasting (>1 min. Furthermore, disruption of the Varroa volatile detection was accompanied by a reversal of the mite's preference from a nurse to a forager bee. Long-term inhibition of the electrophysiological responses of mites to the tested compounds was a good predictor for an alteration in the mite's host preference. CONCLUSIONS: These data indicate the potential of the selected compounds to disrupt the Varroa--honey bee associations, thus opening new avenues for Varroa control.

  19. Hygienic and grooming behaviors in African and European honeybees-New damage categories in Varroa destructor.

    Science.gov (United States)

    Nganso, Beatrice T; Fombong, Ayuka T; Yusuf, Abdullahi A; Pirk, Christian W W; Stuhl, Charles; Torto, Baldwyn

    2017-01-01

    Varroa destructor is an ectoparasitic pest of honeybees, and a threat to the survival of the apiculture industry. Several studies have shown that unlike European honeybees, African honeybee populations appear to be minimally affected when attacked by this mite. However, little is known about the underlying drivers contributing to survival of African honeybee populations against the mite. We hypothesized that resistant behavioral defenses are responsible for the survival of African honeybees against the ectoparasite. We tested this hypothesis by comparing grooming and hygienic behaviors in the African savannah honeybee Apis mellifera scutellata in Kenya and A. mellifera hybrids of European origin in Florida, USA against the mite. Grooming behavior was assessed by determining adult mite infestation levels, daily mite fall per colony and percentage mite damage (as an indicator of adult grooming rate), while hygienic behavior was assessed by determining the brood removal rate after freeze killing a section of the brood. Our results identified two additional undescribed damaged mite categories along with the six previously known damage categories associated with the grooming behavior of both honeybee subspecies. Adult mite infestation level was approximately three-fold higher in A. mellifera hybrids of European origin than in A. m. scutellata, however, brood removal rate, adult grooming rate and daily natural mite fall were similar in both honeybee subspecies. Unlike A. mellifera hybrids of European origin, adult grooming rate and brood removal rate did not correlate with mite infestation levels on adult worker honeybee of A. m. scutellata though they were more aggressive towards the mites than their European counterparts. Our results provide valuable insights into the tolerance mechanisms that contribute to the survival of A. m. scutellata against the mite.

  20. Varroa destructor induces changes in the expression of immunity-related genes during the development of Apis mellifera worker and drone broods.

    Science.gov (United States)

    Zaobidna, Ewa A; Żółtowska, Krystyna; Łopieńska-Biernat, Elżbieta

    2017-12-20

    The ectoparasitic mite Varroa destructor has emerged as the major pest of honeybees. Despite extensive research efforts, the pathogenesis of varroosis has not been fully explained. Earlier studies suggested that V. destructor infestation leads to the suppression of the host's immune system. The aim of this study was to analyze the immune responses of 14 genes in the Toll signal transduction pathways, including effector genes of antimicrobial peptides (AMPs), in developing Apis mellifera workers and drones infested with V. destructor. Four developmental stages (L5 larvae, prepupae, and 2 pupal stages) and newly emerged imagines were analyzed. In workers, the most significant changes were observed in L5 larvae in the initial stages of infestation. A significant increase in the relative expression of 10 of the 14 analyzed genes, including defensin-1 and defensin-2, was observed in infested bees relative to non-infested individuals. The immune response in drones developed at a slower rate. The expression of genes regulating cytoplasmic signal transduction increased in prepupae, whereas the expression of defensin-1 and defensin-2 effector genes increased in P3 pupae with red eyes. The expression of many immunity-related genes was silenced in successive life stages and in imagines, and it was more profound in workers than in drones. The results indicate that V. destructor significantly influences immune responses regulated by the Toll signal transduction pathway in bees. In infested bees, the observed changes in Toll pathway genes varied between life stages and the sexes.

  1. Using an in vitro system for maintaining Varroa destructor mites on Apis mellifera hosts: Studies of mite longevity and feeding behavior

    Science.gov (United States)

    Varroa destructor mites (Vd) are ectoparasites of Apis mellifera honey bees, and the damage they inflict on hosts is a likely causative factor of recent poor honey bee colony performance. Much research has produced an arsenal of control agents against Vd, which have become resistant to many chemical...

  2. Changes in infestation, cell cap condition, and reproductive status of Varroa destructor (Mesostigmata: Varrroidae) in brood exposed to honey bees with Varroa sensitive hygiene

    Science.gov (United States)

    Honey bees (Apis mellifera L.) bred for Varroa sensitive hygiene (VSH) selectively remove pupae infested with Varroa destructor Anderson & Trueman from capped brood that is inserted into the nest. After one week, remaining brood cells tend to have been uncapped and recapped, and remaining mites are...

  3. Modulation of nonessential amino acid biosynthetic pathways in virulent Hessian fly larvae (Mayetiola destructor), feeding on susceptible host wheat (Triticum aestivum)

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    Hessian fly (Mayetiola destructor), an obligate plant-parasitic gall midge, is an important dipteran pest of wheat (Triticum aestivum). The insect employs an effector-based feeding strategy to reprogram the host plant to be nutritionally beneficial for the developing larva by inducing formation of p...

  4. Differential responses of Africanized and European honey bees (Apis mellifera) to viral replication following mechanical transmission or Varroa destructor parasitism.

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    Hamiduzzaman, Mollah Md; Guzman-Novoa, Ernesto; Goodwin, Paul H; Reyes-Quintana, Mariana; Koleoglu, Gun; Correa-Benítez, Adriana; Petukhova, Tatiana

    2015-03-01

    For the first time, adults and brood of Africanized and European honey bees (Apis mellifera) were compared for relative virus levels over 48 h following Varroa destructor parasitism or injection of V. destructor homogenate. Rates of increase of deformed wing virus (DWV) for Africanized versus European bees were temporarily lowered for 12h with parasitism and sustainably lowered over the entire experiment (48 h) with homogenate injection in adults. The rates were also temporarily lowered for 24h with parasitism but were not affected by homogenate injection in brood. Rates of increase of black queen cell virus (BQCV) for Africanized versus European bees were similar with parasitism but sustainably lowered over the entire experiment with homogenate injection in adults and were similar for parasitism and homogenate injection in brood. Analyses of sac brood bee virus and Israeli acute paralysis virus were limited as detection did not occur after both homogenate injection and parasitism treatment, or levels were not significantly higher than those following control buffer injection. Lower rates of replication of DWV and BQCV in Africanized bees shows that they may have greater viral resistance, at least early after treatment. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Expression of the Prophenoloxidase Gene and Phenoloxidase Activity, During the Development of Apis Mellifera Brood Infected with Varroa Destructor

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    Zaobidna Ewa A.

    2015-12-01

    Full Text Available The pathogenesis of varroasis has not been fully explained despite intensive research. Earlier studies suggested that parasitic infections caused by Varroa destructor mites were accompanied by immunosuppression in the host organism. The objective of this study was to analyse the influence of varroasis on one of the immune pathway in Apis mellifera measured by the expression of the prophenoloxidase (proPO gene and the enzymatic activity of this gene’s product, phenoloxidase (EC 1.14.18.1. An evaluation was done of five developmental stages of honey bee workers and drones. The relative expression of proPO decreased in infected individuals. The only exceptions were worker prepupae (PP and drone pupae with brown eyes and dark brown thorax (P5 where propo gene expression was 1.8-fold and 1.5-fold higher, respectively, than in the control. Phenoloxidase (PO activity was 2.8-fold higher in infected pp workers and 2-fold higher in p5 drones in comparison with uninfected bees. Phenoloxidase activity was reduced in the remaining developmental stages of infected workers and drones. The relative expression of proPO was positively correlated with the relative PO activity in both workers (r = 0.988 and drones (r = 0.996. The results of the study indicate that V. destructor significantly influences the phenoloxidase-dependent immune pathway in honey bees.

  6. Taxa de Infestação da Varroa destructor em colônias de Apis mellifera L. no Agreste Meridional de Pernambuco

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    Deygnon Cavalcanti Clementino

    2016-08-01

    Full Text Available O presente trabalho teve como objetivo verificar a taxa de infestação da Varroa destructor em colônias de Apis mellifera L. proveniente de apiário no município de Lagoa do Ouro, Agreste Meridional de Pernambuco. A pesquisa foi realizada no mês de setembro de 2015. Participaram do estudo 15 colônias, em que foram coletadas em média 227 abelhas adultas de cada colmeia e acondicionadas em recipientes contendo álcool a 70%. Após as coletas a campo, as amostras foram transportadas para o laboratório de Biologia Animal da Universidade Federal Rural de Pernambuco/Unidade Acadêmica de Garanhuns, para a realização das análises e quantificação dos ácaros. Os resultados demonstraram que 100% das amostras estavam parasitadas com o ácaro, sendo que a média geral da taxa de infestação foi de 6,16%. O grau de infestação pela Varroa destructor observado nas colônias variou de 0,93% a 11,15%. Conclui-se que as colônias analisadas apresentam diferentes níveis de infestação pelo ácaro Varroa destructor.Infestation rate of Varroa destructor in Apis mellifera L. colonies in the South Agreste of PernambucoAbstract: This study aimed to verify the infestation rate of Varroa destructor in Apis mellifera L. colonies in the apiary from Lagoa do Ouro County, South Agreste of Pernambuco. The survey was conducted in September 2015. The study included 15 colonies, which were collected on average 227 adult bees in each hive and placed in vials containing 70% alcohol. After harvesting the field, the samples were transported to the Animal Biology Laboratory at the Federal Rural University of Pernambuco/Academic Unit of Garanhuns, to perform the analysis and quantification of mites. The results showed that 100% of the samples were infested with mites, and the overall average infestation rate was 6.16%. The degree of infestation by Varroa destructor observed in colonies ranged from 0.93% to 11.15%. It is concluded that the analyzed colonies have

  7. Study of temperature-growth interactions of entomopathogenic fungi with potential for control of Varroa destructor (Acari: Mesostigmata) using a nonlinear model of poikilotherm development.

    Science.gov (United States)

    Davidson, G; Phelps, K; Sunderland, K D; Pell, J K; Ball, B V; Shaw, K E; Chandler, D

    2003-01-01

    To investigate the thermal biology of entomopathogenic fungi being examined as potential microbial control agents of Varroa destructor, an ectoparasite of the European honey bee Apis mellifera. Colony extension rates were measured at three temperatures (20, 30 and 35 degrees C) for 41 isolates of entomopathogenic fungi. All of the isolates grew at 20 and 30 degrees C but only 11 isolates grew at 35 degrees C. Twenty-two isolates were then selected on the basis of appreciable growth at 30-35 degrees C (the temperature range found within honey bee colonies) and/or infectivity to V. destructor, and their colony extension rates were measured at 10 temperatures (12.5-35 degrees C). This data were then fitted to Schoolfield et al. [J Theor Biol (1981)88:719-731] re-formulation of the Sharpe and DeMichele [J Theor Biol (1977)64:649-670] model of poikilotherm development. Overall, this model accounted for 87.6-93.9% of the data variance. Eleven isolates exhibited growth above 35 degrees C. The optimum temperatures for extension rate ranged from 22.9 to 31.2 degrees C. Only three isolates exhibited temperature optima above 30 degrees C. The super-optimum temperatures (temperature above the optimum at which the colony extension rate was 10% of the maximum rate) ranged from 31.9 to 43.2 degrees C. The thermal requirements of the isolates examined against V. destructor are well matched to the temperatures in the broodless areas of honey bee colonies, and a proportion of isolates, should also be able to function within drone brood areas. Potential exists for the control of V. destructor with entomopathogenic fungi in honey bee colonies. The methods employed in this study could be utilized in the selection of isolates for microbial control prior to screening for infectivity and could help in predicting the activity of a fungal control agent of V. destructor under fluctuating temperature conditions.

  8. A sex pheromone receptor in the Hessian fly Mayetiola destructor (Diptera, Cecidomyiidae

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    Martin N. Andersson

    2016-09-01

    Full Text Available The Hessian fly, Mayetiola destructor Say (Diptera, Cecidomyiidae, is a pest of wheat and belongs to a group of gall-inducing herbivores. This species has a unique life history and several ecological features that differentiate it from other Diptera such as Drosophila melanogaster and blood-feeding mosquitoes. These features include a short, non-feeding adult life stage (1-2 days and the use of a long-range sex pheromone produced and released by adult females. Sex pheromones are detected by members of the odorant receptor (OR family within the Lepidoptera, but no receptors for similar long-range sex pheromones have been characterized from the Diptera. Previously, 122 OR genes have been annotated from the Hessian fly genome, with many of them showing sex-biased expression in the antennae. Here we have expressed, in HEK293 cells, five MdesORs that display male-biased expression in antennae, and we have identified MdesOR115 as a Hessian fly sex pheromone receptor. MdesOR115 responds primarily to the sex pheromone component (2S,8E,10E-8,10-tridecadien-2-yl acetate, and secondarily to the corresponding Z,E-isomer. Certain sensory neuron membrane proteins (i.e., SNMP1 are important for responses of pheromone receptors in flies and moths. The Hessian fly genome is unusual in that it encodes six SNMP1 paralogues, of which five are expressed in antennae. We co-expressed each of the five antennal SNMP1 paralogues together with each of the five candidate sex pheromone receptors from the Hessian fly and found that they do not influence the response of MdesOR115, nor do they confer responsiveness in any of the non-responsive ORs to any of the sex pheromone components identified to date in the Hessian fly. Using Western blots, we detected protein expression of MdesOrco, all MdesSNMPs, and all MdesORs except for MdesOR113, potentially explaining the lack of response from this OR. In conclusion, we report the first functional characterization of an OR from the

  9. Gene-knockdown in the honey bee mite Varroa destructor by a non-invasive approach: studies on a glutathione S-transferase

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    Campbell Ewan M

    2010-08-01

    Full Text Available Abstract Background The parasitic mite Varroa destructor is considered the major pest of the European honey bee (Apis mellifera and responsible for declines in honey bee populations worldwide. Exploiting the full potential of gene sequences becoming available for V. destructor requires adaptation of modern molecular biology approaches to this non-model organism. Using a mu-class glutathione S-transferase (VdGST-mu1 as a candidate gene we investigated the feasibility of gene knockdown in V. destructor by double-stranded RNA-interference (dsRNAi. Results Intra-haemocoelic injection of dsRNA-VdGST-mu1 resulted in 97% reduction in VdGST-mu1 transcript levels 48 h post-injection compared to mites injected with a bolus of irrelevant dsRNA (LacZ. This gene suppression was maintained to, at least, 72 h. Total GST catalytic activity was reduced by 54% in VdGST-mu1 gene knockdown mites demonstrating the knockdown was effective at the translation step as well as the transcription steps. Although near total gene knockdown was achieved by intra-haemocoelic injection, only half of such treated mites survived this traumatic method of dsRNA administration and less invasive methods were assessed. V. destructor immersed overnight in 0.9% NaCl solution containing dsRNA exhibited excellent reduction in VdGST-mu1 transcript levels (87% compared to mites immersed in dsRNA-LacZ. Importantly, mites undergoing the immersion approach had greatly improved survival (75-80% over 72 h, approaching that of mites not undergoing any treatment. Conclusions Our findings on V. destructor are the first report of gene knockdown in any mite species and demonstrate that the small size of such organisms is not a major impediment to applying gene knockdown approaches to the study of such parasitic pests. The immersion in dsRNA solution method provides an easy, inexpensive, relatively high throughput method of gene silencing suitable for studies in V. destructor, other small mites and

  10. Importance of brood maintenance terms in simple models of the honeybee - Varroa destructor - acute bee paralysis virus complex

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    Hermann J. Eberl

    2010-09-01

    Full Text Available We present a simple mathematical model of the infestation of a honeybee colony by the Acute Paralysis Virus, which is carried by parasitic varroa mites (Varroa destructor. This is a system of nonlinear ordinary differential equations for the dependent variables: number of mites that carry the virus, number of healthy bees and number of sick bees. We study this model with a mix of analytical and computational techniques. Our results indicate that, depending on model parameters and initial data, bee colonies in which the virus is present can, over years, function seemingly like healthy colonies before they decline and disappear rapidly (e.g. Colony Collapse Disorder, wintering losses. This is a consequence of the fact that a certain number of worker bees is required in a colony to maintain and care for the brood, in order to ensure continued production of new bees.

  11. Composition of fatty acids in the Varroa destructor mites and their hosts, Apis mellifera drone-prepupae.

    Science.gov (United States)

    Dmitryjuk, Małgorzata; Zalewski, Kazimierz; Raczkowski, Marek; Żółtowska, Krystyna

    2015-01-01

    The fatty acid (FA) profile of lipids extracted from the Varroa destructor parasitic mite and its host, drone-prepupae of Apis mellifera, was determined by gas chromatography (GC). The percentages of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) were generally similar in parasites and their hosts. Fatty acids were arranged in the following descending order based on their content: MUFAs (ca. 52-55%), SFAs (ca. 41%) and PUFAs (ca. 3%). The predominant fatty acids were oleic acid (46% in mites, 44% in prepupae) and palmitic acid (23% and 30%, respectively). Varroa parasites differed from their hosts in the quantity of individual FAs and in their FA profiles. Three PUFAs noted in the host were not observed in parasitic mites, whereas the presence of C21:0, C24:0 and C22:1 FAs was reported in mites, but not in drones.

  12. Identification of IgE-binding proteins from Lepidoglyphus destructor and production of monoclonal antibodies to a major allergen.

    Science.gov (United States)

    Ventas, P; Carreira, J; Polo, F

    1991-08-01

    The allergen composition of one of the most important storage mites, Lepidoglyphus destructor, has been studied by immunodetection after SDS-PAGE with individual patient sera. An allergenic polypeptide of 14 kDa was identified with 95% of the sera. This major allergen was isolated in the supernatant of 60% ammonium sulfate salt precipitation of the whole extract, which was subsequently used to immunize BALB/c mice so as to produce monoclonal antibodies. Four mAbs recognizing molecules with IgE-binding ability were obtained. The specificity of the mAbs was assayed against different allergenic extracts, and the molecules recognized by them were characterized by immunoblotting. Two mAbs (Le5B5 and Le9E4) were directed to the 14-kDa allergen; the other two to several proteins of lesser allergenic significance.

  13. Virulence and site of infection of the fungus, Hirsutella thompsonii, to the honey bee ectoparasitic mite, Varroa destructor.

    Science.gov (United States)

    Peng, Christine Y S; Zhou, Xinsheng; Kaya, Harry K

    2002-11-01

    The Varroa mite, Varroa destructor, is recognized as the most serious pest of both managed and feral Western honey bee (Apis mellifera) in the world. The mite has developed resistance to fluvalinate, an acaricide used to control it in beehives, and fluvalinate residues have been found in the beeswax, necessitating an urgent need to find alternative control measures to suppress this pest. Accordingly, we investigated the possibility of using the fungus, Hirsutella thompsonii, as a biocontrol agent of the Varroa mite. Among the 9 isolates of H. thompsonii obtained from the University of Florida and the USDA, only the 3 USDA isolates (ARSEF 257, 1947 and 3323) were infectious to the Varroa mite in laboratory tests. The mite became infected when it was allowed to walk on a sporulating H. thompsonii culture for 5 min. Scanning electron micrographs revealed that the membranous arolium of the mite leg sucker is the focus of infection where the fungal conidia adhered and germinated. The infected mites died from mycosis, with the lethal times to kill 50% (LT(50)s) dependent on the fungal isolates. Thus, the LT(50)s were 52.7, 77.2, and 96.7h for isolates 3323, 257, and 1947, respectively. Passage of H. thompsonii through Varroa mite three times significantly reduced the LT(50)s of isolates 257 and 1947 (P<0.05) but not the LT(50) of isolate 3323. The fungus did not infect the honey bee in larval, prepupal, pupal, and adult stages under our laboratory rearing conditions. Our encouraging results suggest that some isolates of H. thompsonii have the potential to be developed as a biocontrol agent for V. destructor. However, fungal infectivity against the mites under beehive conditions needs to be studied before any conclusion can be made.

  14. Search and studying of salt resisting bacteria -destructors of organochlorine pesticides with help of tritium labeled PCBs

    International Nuclear Information System (INIS)

    Kim, A.A.; Djuraeva, G.T.; Dadakhanov, J.A.; Djumaniyazova, G.I.; Yadgarov, Kh.T.; Zinovev, P.V.; Norbaeva, Kh.

    2006-01-01

    Full text: Salinization of soils is one of serious problems of agriculture of Uzbekistan. The problem is also aggravated as the salted soils are strongly contaminated with pesticides. We isolated aboriginal active strains of bacteria- destructors of organochlorine compounds from soils contaminated by pesticides (HCCH, DDT, PCBs). We investigated their cultural-morphological and physiological -biochemical properties and determined their taxonomic position. In laboratory experiments the effect of various concentrations of NaCl - 3%-5-7-10-20-30-40-50 % and reproduction of the active strains-destructors was investigated. It was found that the culture number 20 stands the NaCl concentration - up to 3 %, culture number 505 - up to 7 % salt in medium that specifies ability of this culture to survive in the middle salinated soils, cultures number 28 and 33 stand the NaCl concentration up to 30-40 % that characterize their survival rate in strongly salinated soils; the culture number 26 stood the NaCl concentration up to 50 % that characterizes its ability to survive and propagate in brackish soils. With the help of designed radiochemical methods we had been explored ability of the active salt resisting strains of bacteria to utilize and destroy the tritium labeled PCBs. The precise quantity and quality characteristics of the PCB-destructive activity of each investigated strain were received. The salt resisting strains of bacteria having high PCB-destructive activity were determined. At present, investigation on development of the new biological preparation designed for destruction of persistent organochlorine compounds in salted soils are carried out. (author)

  15. Comparison of the efficacy of Apiguard (thymol and Apivar (amitraz in the control of Varroa destructor (Acari: Varroidae

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    M. Mar Leza

    2015-09-01

    Full Text Available The present study compared the efficacy of Apivar (a.i. amitraz and Apiguard (a.i. thymol in controlling the mite Varroa destructor during spring 2010 and autumn 2011, in the Balearic Islands (Spain. Number of fallen mites (NFM was counted weekly and the efficacy of treatments was evaluated by using the percentage of reduction of the average daily fallen mites (%R. During spring assay, the average NFM was highly reduced in Apiguard (89.8% compared to Apivar (64.3% group, with significant differences between Apiguard and control group (untreated group in post-treatment week. In autumn assay, Apivar and Apiguard colonies had an average reduction of the NFM of 17.9% and 30.8% respectively, showing a tendency in reduction between control and Apiguard group in post-treatment week. In both assays, %R was higher in Apiguard than in Apivar, but no significant differences were found between treatments in any of the seasons. Apiguard was less efficacious during November-December, probably due to the low external temperatures that hampered an optimal volatilization of the product. The lower efficacy of Apivar is probably related to the resistance of V. destructor to this chemical miticide, which has been used during the last 30 years. Results of this study showed that in Mediterranean conditions, spring is an appropriate period for applying Apiguard to the colonies, whereas application in late autumn would decrease the efficacy of the product. Apiguard may represent an alternative product for integrated control due to the low risk of mite resistance and residues in bee products.

  16. Comparison of the efficacy of Apiguard (thymol) and Apivar (amitraz) in the control of Varroa destructor (Acari: Varroidae)

    Energy Technology Data Exchange (ETDEWEB)

    Leza, M.M.; Lladó, G.; Miranda-Chueca, M.A.

    2015-07-01

    The present study compared the efficacy of Apivar (a.i. amitraz) and Apiguard (a.i. thymol) in controlling the mite Varroa destructor during spring 2010 and autumn 2011, in the Balearic Islands (Spain). Number of fallen mites (NFM) was counted weekly and the efficacy of treatments was evaluated by using the percentage of reduction of the average daily fallen mites (%R). During spring assay, the average NFM was highly reduced in Apiguard (89.8%) compared to Apivar (64.3%) group, with significant differences between Apiguard and control group (untreated group) in post-treatment week. In autumn assay, Apivar and Apiguard colonies had an average reduction of the NFM of 17.9% and 30.8% respectively, showing a tendency in reduction between control and Apiguard group in post-treatment week. In both assays, %R was higher in Apiguard than in Apivar, but no significant differences were found between treatments in any of the seasons. Apiguard was less efficacious during November-December, probably due to the low external temperatures that hampered an optimal volatilization of the product. The lower efficacy of Apivar is probably related to the resistance of V. destructor to this chemical miticide, which has been used during the last 30 years. Results of this study showed that in Mediterranean conditions, spring is an appropriate period for applying Apiguard to the colonies, whereas application in late autumn would decrease the efficacy of the product. Apiguard may represent an alternative product for integrated control due to the low risk of mite resistance and residues in bee products. (Author)

  17. Reproduction of Varroa destructor and offspring mortality in worker and drone brood cells of Africanized honey bees.

    Science.gov (United States)

    Calderón, R A; Ureña, S; van Veen, J W

    2012-04-01

    Varroa destructor is known to be the most serious parasite of Apis mellifera worldwide. In order to reproduce varroa females enter worker or drone brood shortly before the cell is sealed. From March to December 2008, the reproductive rate and offspring mortality (mature and immature stages), focusing on male absence and male mortality of V. destructor, was investigated in naturally infested worker and drone brood of Africanized honey bees (AHB) in Costa Rica. Data were obtained from 388 to 403 single infested worker and drone brood cells, respectively. Mite fertility in worker and drone brood cells was 88.9 and 93.1%, respectively. There was no difference between the groups (X(2) = 3.6, P = 0.06). However, one of the most significant differences in mite reproduction was the higher percentage of mites producing viable offspring in drone cells (64.8%) compared to worker cells (37.6%) (X(2) = 57.2, P drone cells was high in the protonymph stage (mobile and immobile). A significant finding was the high rate of male mortality. The worker and drone brood revealed that 23.9 and 6.9%, respectively, of the adult male offspring was found dead. If the absence (missing) of the male and adult male mortality are taken together the percentage of cells increased to 40.0 and 21.3% in worker and drone cells, respectively (X(2) = 28.8, P < 0.05). The absence of the male or male mortality in a considerable number of worker cells naturally infested with varroa is the major factor in our study which reduces the production of viable daughters in AHB colonies in Costa Rica.

  18. Vergleichende Untersuchungen zur Widerstandsfähigkeit von \\(\\textit {Apis mellifera}\\) gegenüber \\(\\textit {Varroa destructor}\\) in Deutschland und Südafrika

    OpenAIRE

    Bosch, Christoph (M. Sc.)

    2016-01-01

    Die Milbe \\(\\textit {Varroa destructor}\\) ist einer der bedeutendsten Parasiten der Westlichen Honigbiene \\(\\textit {Apis mellifera}\\). Mit der Ausbreitung entwickelten sich \\(\\it Varroa\\)-resistenzen bei Unterarten von \\(\\textit {A. mellifera}\\). In der vorliegenden Arbeit wurden ausgewählte Faktoren, die zur Widerstandsfähigkeit beitragen können, bei der anfälligen \\(\\textit {A. m. carnica}\\) in Deutschland und der resistenten \\(\\textit {A. m. scutellata}\\) in Südafrika untersucht. Dabei wu...

  19. Characterization of the Copy Number and Variants of Deformed Wing Virus (DWV in the Pairs of Honey Bee Pupa and Infesting Varroa destructor or Tropilaelaps mercedesae

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    Yunfei Wu

    2017-08-01

    Full Text Available Recent honey bee colony losses, particularly during the winter, have been shown to be associated with the presence of both ectoparasitic mites and Deformed Wing Virus (DWV. Whilst the role of Varroa destructor mites as a viral vector is well established, the role of Tropilaelaps mercedesae mites in viral transmission has not been fully investigated. In this study, we tested the effects that V. destructor and T. mercedesae infestation have on fluctuation of the DWV copy number and alteration of the virus variants in honey bees by characterizing individual pupae and their infesting mites. We observed that both mite species were associated with increased viral copy number in honey bee pupae. We found a positive correlation between DWV copy number in pupae and copy number in infesting mites, and the same DWV type A variant was present in either low or high copy number in both honey bee pupae and infesting V. destructor. These data also suggest that variant diversity is similar between honey bee pupae and the mites that infest them. These results support a previously proposed hypothesis that DWV suppresses the honey bee immune system when virus copy number reaches a specific threshold, promoting greater replication.

  20. Correlation of proteome-wide changes with social immunity behaviors provides insight into resistance to the parasitic mite, Varroa destructor, in the honey bee (Apis mellifera).

    Science.gov (United States)

    Parker, Robert; Guarna, M Marta; Melathopoulos, Andony P; Moon, Kyung-Mee; White, Rick; Huxter, Elizabeth; Pernal, Stephen F; Foster, Leonard J

    2012-06-29

    Disease is a major factor driving the evolution of many organisms. In honey bees, selection for social behavioral responses is the primary adaptive process facilitating disease resistance. One such process, hygienic behavior, enables bees to resist multiple diseases, including the damaging parasitic mite Varroa destructor. The genetic elements and biochemical factors that drive the expression of these adaptations are currently unknown. Proteomics provides a tool to identify proteins that control behavioral processes, and these proteins can be used as biomarkers to aid identification of disease tolerant colonies. We sampled a large cohort of commercial queen lineages, recording overall mite infestation, hygiene, and the specific hygienic response to V. destructor. We performed proteome-wide correlation analyses in larval integument and adult antennae, identifying several proteins highly predictive of behavior and reduced hive infestation. In the larva, response to wounding was identified as a key adaptive process leading to reduced infestation, and chitin biosynthesis and immune responses appear to represent important disease resistant adaptations. The speed of hygienic behavior may be underpinned by changes in the antenna proteome, and chemosensory and neurological processes could also provide specificity for detection of V. destructor in antennae. Our results provide, for the first time, some insight into how complex behavioural adaptations manifest in the proteome of honey bees. The most important biochemical correlations provide clues as to the underlying molecular mechanisms of social and innate immunity of honey bees. Such changes are indicative of potential divergence in processes controlling the hive-worker maturation.

  1. Evaluación de extractos de ocho especies vegetales en el control de mildeo velloso (Peronospora destructor Berk en cebolla de bulbo (Allium cepa L.

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    Pedro Enrique Cubides-Hernández

    2015-01-01

    Full Text Available Extractos de ocho especies vegetales: eucalipto (Eucalytus globulus, cola de caballo (Equisetum bogotense, ortiga (Urtica urens, manzanilla (Matricaria chamomilla, caléndula (Calendula officinalis, yerbabuena (Menta viridis, ajo (Allium sativum y clavo (Syzygum aromaticum, preparados por el método de decocción (100 g/l, fueron evaluados en cuanto a su eficiencia en el control de P. destructor en cebolla de bulbo. Se utilizó el diseño experimental de bloques al azar con cuatro repeticiones y siete aplicaciones (52, 60, 68, 76,84, 92 y 100 días después del trasplante, incluyendo un testigo químico Ridomil (metalaxil + mancozeb (2 g/l y el testigo absoluto; se evaluaron la incidencia y severidad de P. destructor, y el número y el peso de bulbos cosechados. El ANOVA mostró que de las siete aplicaciones realizadas, la última presentó efectos estadísticos en el control de la incidencia y severidad de P. destructor. El extracto de manzanilla superó al Ridomil en el control de la incidencia y severidad de P. destructor sin diferencias estadísticas entre sí, y fue significativamente mejor al observado con los extractos de eucalipto, cola de caballo, caléndula y el testigo; el extracto de manzanilla superó al testigo químico en el número y peso de bulbos de cebolla sin presentar diferencias estadísticas, y fue significativamente mejor al obtenido con los extractos de eucalipto, cola de caballo, ortiga, caléndula, yerbabuena, clavo y el testigo absoluto. El extracto de manzanilla es una alternativa ecológica que se debe tener en cuenta en el manejo integrado de P. destructor en cebolla de bulbo.

  2. A Mathematical Model of Forager Loss in Honeybee Colonies Infested with Varroa destructor and the Acute Bee Paralysis Virus.

    Science.gov (United States)

    Ratti, Vardayani; Kevan, Peter G; Eberl, Hermann J

    2017-06-01

    We incorporate a mathematical model of Varroa destructor and the Acute Bee Paralysis Virus with an existing model for a honeybee colony, in which the bee population is divided into hive bees and forager bees based on tasks performed in the colony. The model is a system of five ordinary differential equations with dependent variables: uninfected hive bees, uninfected forager bees, infected hive bees, virus-free mites and virus-carrying mites. The interplay between forager loss and disease infestation is studied. We study the stability of the disease-free equilibrium of the bee-mite-virus model and observe that the disease cannot be fought off in the absence of varroacide treatment. However, the disease-free equilibrium can be stable if the treatment is strong enough and also if the virus-carrying mites become virus-free at a rate faster than the mite birth rate. The critical forager loss due to homing failure, above which the colony fails, is calculated using simulation experiments for disease-free, treated and untreated mite-infested, and treated virus-infested colonies. A virus-infested colony without varroacide treatment fails regardless of the forager mortality rate.

  3. Development of the system nematode, Ditylenchus Dipsaci (Kuehn) Filipjev, and the potato tuber nematode, D. Destructor thore, after gamma irradiation

    International Nuclear Information System (INIS)

    Ignatowicz, S.; Karnkowski, W.

    1996-01-01

    Juvenile and adult nematodes emerged from onion and garlic samples on the 3 rd week after irradiation with doses up to 0.5 kGy and from potato treated with doses up to 2.0 kGy. However, irradiation of onion infected with Ditylenchus dipsaci caused the inhibition of the development and growth of juvenile nematodes to mature forms. Doses of gamma radiation ranging from 0.1 to 0.5 kGy had only a slight effect, if any, on the development and growth of D. dipsaci nematodes infecting garlic, but they increased juvenile mortality. Gamma radiation at doses up to 2.0 kGy induced increased mortality of nematode juveniles of the potato tuber nematode, D. destructor but less so inhibited their development to mature forms. Nematodes were found to be resistant to irradiation treatment. Therefore the use of gamma irradiation for nematode disinfestation of agricultural products seems to be impractical, if the aim of the treatment is to kill these pests within a few weeks. The level of radiation required to kill nematodes in infected plants would damage plant tissues so that the further storage of vegetables will be impossible. (author). 22 refs, 3 figs, 2 tabs

  4. Eficacia del Oxavar® para el Control del Ácaro Varroa destructor (Varroidae en Colmenas de Apis mellifera (Apidae Efficacy of Oxavar® to control the mite Varroa destructor (Varroidae in honeybee colonies of Apis mellifera (Apidae

    Directory of Open Access Journals (Sweden)

    Jorge Augusto Marcangeli

    2003-12-01

    Full Text Available El objetivo del trabajo fue evaluar la eficacia del producto Oxavar® para el control del ácaro Varroa destructor (Anderson & Trueman en colmenas de abejas Apis mellifera durante la primavera de 2002 y otoño de 2003. El trabajo se llevó a cabo en el apiario experimental del Centro de Extensión Apícola ubicado en Coronel Vidal, provincia de Buenos Aires. Se trabajó sobre un total de 20 colmenas tipo Langstroth que se dividieron en dos grupos iguales. El primer grupo recibió 5 ml de Oxavar® (323 g en 5000 ml de agua destilada por cuadro cubierto por abejas. El segundo grupo, el testigo, recibió 5 ml de agua destilada por cuadro cubierto por abejas. Ambos grupos recibieron tres dosis a intervalos de siete días. Semanalmente, se recolectaron los ácaros muertos caídos en pisos especiales que evitaban que las abejas los eliminen. Posteriormente, en los dos grupos se colocaron tiras del producto Apistan® para eliminar los ácaros remanentes en las colonias y poder así calcular la eficacia del tratamiento. El producto Oxavar® presentó una eficacia promedio de 85,5 % ± 2,8 durante la primavera y 86,1% ± 2,6 durante el otoño, no mostrando diferencias significativas entre las estaciones (p> 0,05. En ambos casos se registraron diferencias significativas frente al grupo control (pThe aim of this work was to evaluate the acaricide efficacy of Oxavar® to control Varroa destructor (Anderson & Trueman in Apis mellifera (L colonies during the spring 2002 and the autumn 2003. Work was done at “Centro de Extensión Apícola” experimental apiary located in Coronel Vidal, province of Buenos Aires. Twenty Langstroth hives were used divided in two equal groups. The first group received 5 ml of Oxavar® (323 g in 5000 ml of destiled water per comb covered by honeybees and the second one received 5 ml of destiled water. Both groups received three dosages at seven day periods. Dead mites were collected weekly from special floors in order to avoid

  5. Use of costic acid, a natural extract from Dittrichia viscosa, for the control of Varroa destructor, a parasite of the European honey bee

    Directory of Open Access Journals (Sweden)

    Kalliopi Sofou

    2017-05-01

    Full Text Available Costic acid has been isolated from the plant Dittrichia viscosa and its efficacy against Varroa destructor, a parasite of Apis mellifera, the European honey bee, has been studied. Costic acid exhibited potent in vivo acaricidal activity against the parasite. Initial experiments showed that the compound is not toxic for human umbilical vein endothelial cells (HUVEC at concentrations of up to 230 micromolar (μM, indicating that costic acid could be used as a safe, low-cost and efficient agent for controlling varroosis in honey bee colonies.

  6. Varroa destructor (Mesostigmata: Varroidae in Costa Rica: population dynamics and its influence on the colony condition of Africanized honey bees (Hymenoptera: Apidae

    Directory of Open Access Journals (Sweden)

    Rafael A Calderón

    2008-12-01

    Full Text Available The development of Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae population dynamics in Africanized honey bees, Apis mellifera L. (Hymenoptera: Apidae colonies was monitored from February to July 2004 in Atenas, Costa Rica. A correlation between the mite infestation level and the colony condition was evaluated. For each colony, infestation of varroa in adult bees was measured twice a month. Sticky boards were placed on the bottom boards of each colony to collect fallen mites. The condition of the colonies was evaluated by measuring the amount of brood and adult bees. Our results consistently showed that mite infestation on adult bees increased significantly in the experimental colonies, rising to 10.0% by the end of the experiment. In addition, the mean mite fall increased significantly over the course of the study in the treated (R= 0.72, PLa dinámica poblacional del ácaro Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae en abejas africanizadas, Apis mellifera L. (Hymenoptera: Apidae fue monitoreada de febrero a julio 2004, en Atenas, Costa Rica. Asimismo, se analizó la relación entre el nivel de infestación de varroa y la condición de la colmena. La infestación del ácaro V. destructor fue evaluada en abejas adultas dos veces al mes. Además, se colocaron trampas adhesivas en el fondo de la colmena para recoger los ácaros que caen naturalmente. La condición de la colmena fue determinada midiendo la cantidad de cría y la población de abejas adultas. La infestación del ácaro V. destructor en abejas adultas aumentó significativamente durante el estudio hasta alcanzar un 10.0%. Igualmente, la caída natural de ácaros se incrementó, tanto en colmenas que fueron tratadas previa-mente con un acaricida químico (R= 0.72, P<0.05 como en colmenas sin tratamiento (R= 0.74, P<0.05, hasta llegar a 63.8 y 73.5 ácaros por día, respectivamente. El aumento de la infestación en las colmenas coincidió con una

  7. Obtención de líneas de trigo resistentes a Mayetiola destructor Say en la Campiña Sur de Extremadura

    OpenAIRE

    Del Moral, J.; Delibes de Castro, Ángeles; Martín Sánchez, Juan Antonio; Mejías, A.; López-Braña, Isidoro; Sin Casas, Esther; Montes, Mª J.; Pérez-Rojas, F.; Espinal, F. J.; Senero, M.

    2002-01-01

    La línea H-93-33, homocigota para el gen H27, que confiere resistencia a Mayetiola destructor Say, ha sido cruzada con variedades comerciales de trigo seleccionadas por su calidad harinera y sus características agronómicas. Esos cruzamientos han producido numerosas líneas avanzadas. La línea Ma8, que contiene el gen H27, ha demostrado su resistencia al parásito en condiciones controladas de cámara y campo, y muestra mejores características agronómicas que las variedades comerciales con las...

  8. An Observational Study of Honey Bee Colony Winter Losses and Their Association with Varroa destructor, Neonicotinoids and Other Risk Factors

    Science.gov (United States)

    van der Zee, Romée; Gray, Alison; Pisa, Lennard; de Rijk, Theo

    2015-01-01

    This article presents results of an analysis of honey bee losses over the winter of 2011-2012 in the Netherlands, from a sample of 86 colonies, located at 43 apiaries. The apiaries were selected using spatially stratified random sampling. Colony winter loss data were collected and related to various measures of colony strength recorded in summer, as well as data from laboratory analysis of sample material taken from two selected colonies in each of the 43 apiaries. The logistic regression model which best explained the risk of winter loss included, in order of statistical importance, the variables (1) Varroa destructor mite infestation rate in October 2011, (2) presence of the cyano-substituted neonicotinoids acetamiprid or thiacloprid in the first 2 weeks of August 2011 in at least one of the honey bee matrices honey, bees or bee bread (pollen), (3) presence of Brassica napus (oilseed rape) or Sinapis arvensis (wild mustard) pollen in bee bread in early August 2011, and (4) a measure of the unexplained winter losses for the postal code area where the colonies were located, obtained from a different dataset. We consider in the discussion that reduced opportunities for foraging in July and August because of bad weather may have added substantially to the adverse effects of acetamiprid and thiacloprid. A novel feature of this work is its use of postal code random effects from two other independent datasets collected in the annual national monitoring by questionnaires of winter losses of honey bees in the Netherlands. These were used to plan the sample selection and also in the model fitting of the data in this study. It should however be noted that the results of the present pilot study are based on limited data, which may consequently reveal strong factors but fail to demonstrate possible interaction effects. PMID:26154346

  9. Removal of drone brood from Apis mellifera (Hymenoptera: Apidae) colonies to control Varroa destructor (Acari: Varroidae) and retain adult drones.

    Science.gov (United States)

    Wantuch, Holly A; Tarpy, David R

    2009-12-01

    The parasitic mite Varroa destructor Anderson & Trueman (Acari: Varroidae) has plagued European honey bees, Apis mellifera L. (Hymenoptera: Apidae), in the Americas since its introduction in the 1980s. For many years, these mites were sufficiently controlled using synthetic acaricides. Recently, however, beekeepers have experienced increased resistance by mites to chemical pesticides, which are also known to leave residues in hive products such as wax and honey. Thus there has been increased emphasis on nonchemical integrated pest management control tactics for Varroa. Because mites preferentially reproduce in drone brood (pupal males), we developed a treatment strategy focusing on salvaging parasitized drones while removing mites from them. We removed drone brood from colonies in which there was no acaricidal application and banked them in separate "drone-brood receiving" colonies treated with pesticides to kill mites emerging with drones. We tested 20 colonies divided into three groups: 1) negative control (no mite treatment), 2) positive control (treatment with acaricides), and 3) drone-brood removal and placement into drone-brood receiving colonies. We found that drone-brood trapping significantly lowered mite numbers during the early months of the season, eliminating the need for additional control measures in the spring. However, mite levels in the drone-brood removal group increased later in the summer, suggesting that this benefit does not persist throughout the entire season. Our results suggest that this method of drone-brood trapping can be used as an element of an integrated control strategy to control varroa mites, eliminating a large portion of the Varroa population with limited chemical treatments while retaining the benefits of maintaining adult drones in the population.

  10. Quantitative proteomics reveals divergent responses in Apis mellifera worker and drone pupae to parasitization by Varroa destructor.

    Science.gov (United States)

    Surlis, Carla; Carolan, James C; Coffey, Mary; Kavanagh, Kevin

    Varroa destructor is a haemophagous ectoparasite of honeybees and is considered a major causal agent of colony losses in Europe and North America. Although originating in Eastern Asia where it parasitizes Apis cerana, it has shifted hosts to the western honeybee Apis mellifera on which it has a greater deleterious effect on the individual and colony level. To investigate this important host-parasite interaction and to determine whether Varroa causes different effects on different castes we conducted a label free quantitative proteomic analysis of Varroa-parasitized and non-parasitized drone and worker Apis mellifera pupae. 1195 proteins were identified in total, of which 202 and 250 were differentially abundant in parasitized drone and worker pupae, respectively. Both parasitized drone and worker pupae displayed reduced abundance in proteins associated with the cuticle, lipid transport and innate immunity. Proteins involved in metabolic processes were more abundant in both parasitized castes although the response in workers was more pronounced. A number of caste specific responses were observed including differential abundance of numerous cytoskeletal and muscle proteins, which were of higher abundance in parasitized drones in comparison to parasitized workers. Proteins involved in fatty acid and carbohydrate metabolism were more abundant in parasitized workers as were a large number of ribosomal proteins highlighting either potentially divergent responses to Varroa or a different strategy by the mite when parasitizing the different castes. This data improves our understanding of this interaction and may provide a basis for future studies into improvements to therapy and control of Varroasis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. An Observational Study of Honey Bee Colony Winter Losses and Their Association with Varroa destructor, Neonicotinoids and Other Risk Factors.

    Directory of Open Access Journals (Sweden)

    Romée van der Zee

    Full Text Available This article presents results of an analysis of honey bee losses over the winter of 2011-2012 in the Netherlands, from a sample of 86 colonies, located at 43 apiaries. The apiaries were selected using spatially stratified random sampling. Colony winter loss data were collected and related to various measures of colony strength recorded in summer, as well as data from laboratory analysis of sample material taken from two selected colonies in each of the 43 apiaries. The logistic regression model which best explained the risk of winter loss included, in order of statistical importance, the variables (1 Varroa destructor mite infestation rate in October 2011, (2 presence of the cyano-substituted neonicotinoids acetamiprid or thiacloprid in the first 2 weeks of August 2011 in at least one of the honey bee matrices honey, bees or bee bread (pollen, (3 presence of Brassica napus (oilseed rape or Sinapis arvensis (wild mustard pollen in bee bread in early August 2011, and (4 a measure of the unexplained winter losses for the postal code area where the colonies were located, obtained from a different dataset. We consider in the discussion that reduced opportunities for foraging in July and August because of bad weather may have added substantially to the adverse effects of acetamiprid and thiacloprid. A novel feature of this work is its use of postal code random effects from two other independent datasets collected in the annual national monitoring by questionnaires of winter losses of honey bees in the Netherlands. These were used to plan the sample selection and also in the model fitting of the data in this study. It should however be noted that the results of the present pilot study are based on limited data, which may consequently reveal strong factors but fail to demonstrate possible interaction effects.

  12. An Observational Study of Honey Bee Colony Winter Losses and Their Association with Varroa destructor, Neonicotinoids and Other Risk Factors.

    Science.gov (United States)

    van der Zee, Romée; Gray, Alison; Pisa, Lennard; de Rijk, Theo

    2015-01-01

    This article presents results of an analysis of honey bee losses over the winter of 2011-2012 in the Netherlands, from a sample of 86 colonies, located at 43 apiaries. The apiaries were selected using spatially stratified random sampling. Colony winter loss data were collected and related to various measures of colony strength recorded in summer, as well as data from laboratory analysis of sample material taken from two selected colonies in each of the 43 apiaries. The logistic regression model which best explained the risk of winter loss included, in order of statistical importance, the variables (1) Varroa destructor mite infestation rate in October 2011, (2) presence of the cyano-substituted neonicotinoids acetamiprid or thiacloprid in the first 2 weeks of August 2011 in at least one of the honey bee matrices honey, bees or bee bread (pollen), (3) presence of Brassica napus (oilseed rape) or Sinapis arvensis (wild mustard) pollen in bee bread in early August 2011, and (4) a measure of the unexplained winter losses for the postal code area where the colonies were located, obtained from a different dataset. We consider in the discussion that reduced opportunities for foraging in July and August because of bad weather may have added substantially to the adverse effects of acetamiprid and thiacloprid. A novel feature of this work is its use of postal code random effects from two other independent datasets collected in the annual national monitoring by questionnaires of winter losses of honey bees in the Netherlands. These were used to plan the sample selection and also in the model fitting of the data in this study. It should however be noted that the results of the present pilot study are based on limited data, which may consequently reveal strong factors but fail to demonstrate possible interaction effects.

  13. Assessing in Vitro Acaricidal Effect and Joint Action of a Binary Mixture Between Essential Oil Compounds (Thymol, Phellandrene, Eucalyptol, Cinnamaldehyde, Myrcene, Carvacrol Over Ectoparasitic Mite Varroa Destructor (Acari: Varroidae

    Directory of Open Access Journals (Sweden)

    Brasesco Constanza

    2017-12-01

    Full Text Available Varroa destructor (Anderson & Trueman, 2000 causes the most important parasitosis of beekeeping in the world. For this reason, prevention is needed to avoid colony death. The most typical treatments involve synthetic acaricides. However, the use of these acaricides results in the emergence of resistant populations of mites to these products and in the appearances of drug residues in products of the hives. Compounds of essential oils have emerged as an alternative to traditional acaricides; however the toxicity produced by these mixtures is currently poorly explored. The aim of this work was to assess, by means of in vitro tests with adult bees, how acaricidal action and toxic interactions in a binary mixture of essential oil compounds (Thymol, Phellandrene, Eucalyptol, Cinnamaldehyde, Myrcene, and Carvacrol affect V. destructor. Calculations of LC50 ’s of the individual compounds on A. mellifera and V. destructor made clear that the toxic effect of each compound is different for both species. Thymol and Phellandrene turned out to be lethal for mites at lower concentrations than for bees. The binary mixture of these two substances presented a different toxicity than one produced by each pure compound, as it was highly selective for mites in bioassays at 24 hours through complete exposure to both A. mellifera and V. destructor. These results make such formulations optimal substances to be considered as alternative controls for the parasitosis.

  14. Proteomic analysis of chemosensory organs in the honey bee parasite Varroa destructor: A comprehensive examination of the potential carriers for semiochemicals.

    Science.gov (United States)

    Iovinella, Immacolata; McAfee, Alison; Mastrobuoni, Guido; Kempa, Stefan; Foster, Leonard J; Pelosi, Paolo; Dani, Francesca Romana

    2018-06-15

    We have performed a proteomic analysis on chemosensory organs of Varroa destructor, the honey bee mite, in order to identify putative soluble carriers for pheromones and other olfactory cues emitted by the host. In particular, we have analysed forelegs, mouthparts (palps, chelicera and hypostome) and the second pair of legs (as control tissue) in reproductive and phoretic stages of the Varroa life cycle. We identified 958 Varroa proteins, most of them common to the different organs and stages. Sequence analysis shows that four proteins can be assigned to the odorant-binding protein (OBP)-like class, which bear some similarity to insect OBPs, but so far have only been reported in some Chelicerata. In addition, we have detected the presence of two proteins belonging to the Niemann-Pick family, type C2 (NPC2), which have also been suggested as semiochemical carriers. Biological significance: The mite Varroa destructor is the major parasite of the honey bee and is responsible for great economical losses. The biochemical tools used by Varroa to detect semiochemicals produced by the host are still largely unknown. This work contributes to understand the molecular basis of olfaction in Varroa and, more generally, how detection of semiochemicals has evolved in terrestrial non-hexapod Arthropoda. Moreover, the identification of molecular carriers involved in olfaction can contribute to the development of control strategies for this important parasite. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Evaluation of drone brood removal for management of Varroa destructor (Acari: Varroidae) in colonies of Apis mellifera (Hymenoptera: Apidae) in the northeastern United States.

    Science.gov (United States)

    Calderone, N W

    2005-06-01

    The efficacy of drone brood removal for the management of Varroa destructor Anderson & Trueman in colonies of the honey bee, A. mellifera L., was evaluated. Colonies were treated with CheckMite+ in the fall of 2002. The following spring, quantities of bees and brood were equalized, but colonies were not retreated. The brood nest of each colony consisted of 18 full-depth worker combs and two full-depth drone combs. Each worker comb had drone cells. Standard management practices were used throughout the season. Colonies were randomly assigned to one of two groups. In the control group, drone combs remained in place throughout the season. In the treatment group, drone combs were removed on 16 June, 16 July, 16 August, and 16 September and replaced with empty drone combs (16 June) or with drone combs removed on the previous replacement date. In the early fall, the average mite-to-bee ratio in the control group was significantly greater than the corresponding ratio in the treatment group. Drone brood removal did not adversely affect colony health as measured by the size of the worker population or by honey production. Fall worker populations were similar in the two groups. Honey production in treatment colonies was greater than or similar to production in control colonies. These data demonstrate that drone brood removal can serve as a valuable component in an integrated pest management program for V. destructor and may reduce the need for other treatments on a colony-by-colony basis.

  16. Immune related gene expression in worker honey bee (Apis mellifera carnica) pupae exposed to neonicotinoid thiamethoxam and Varroa mites (Varroa destructor).

    Science.gov (United States)

    Tesovnik, Tanja; Cizelj, Ivanka; Zorc, Minja; Čitar, Manuela; Božič, Janko; Glavan, Gordana; Narat, Mojca

    2017-01-01

    Varroa destructor is one of the most common parasites of honey bee colonies and is considered as a possible co-factor for honey bee decline. At the same time, the use of pesticides in intensive agriculture is still the most effective method of pest control. There is limited information about the effects of pesticide exposure on parasitized honey bees. Larval ingestion of certain pesticides could have effects on honey bee immune defense mechanisms, development and metabolic pathways. Europe and America face the disturbing phenomenon of the disappearance of honey bee colonies, termed Colony Collapse Disorder (CCD). One reason discussed is the possible suppression of honey bee immune system as a consequence of prolonged exposure to chemicals. In this study, the effects of the neonicotinoid thiamethoxam on honey bee, Apis mellifera carnica, pupae infested with Varroa destructor mites were analyzed at the molecular level. Varroa-infested and non-infested honey bee colonies received protein cakes with or without thiamethoxam. Nurse bees used these cakes as a feed for developing larvae. Samples of white-eyed and brown-eyed pupae were collected. Expression of 17 immune-related genes was analyzed by real-time PCR. Relative gene expression in samples exposed only to Varroa or to thiamethoxam or simultaneously to both Varroa and thiamethoxam was compared. The impact from the consumption of thiamethoxam during the larval stage on honey bee immune related gene expression in Varroa-infested white-eyed pupae was reflected as down-regulation of spaetzle, AMPs abaecin and defensin-1 and up-regulation of lysozyme-2. In brown-eyed pupae up-regulation of PPOact, spaetzle, hopscotch and basket genes was detected. Moreover, we observed a major difference in immune response to Varroa infestation between white-eyed pupae and brown-eyed pupae. The majority of tested immune-related genes were upregulated only in brown-eyed pupae, while in white-eyed pupae they were downregulated.

  17. Immune related gene expression in worker honey bee (Apis mellifera carnica pupae exposed to neonicotinoid thiamethoxam and Varroa mites (Varroa destructor.

    Directory of Open Access Journals (Sweden)

    Tanja Tesovnik

    Full Text Available Varroa destructor is one of the most common parasites of honey bee colonies and is considered as a possible co-factor for honey bee decline. At the same time, the use of pesticides in intensive agriculture is still the most effective method of pest control. There is limited information about the effects of pesticide exposure on parasitized honey bees. Larval ingestion of certain pesticides could have effects on honey bee immune defense mechanisms, development and metabolic pathways. Europe and America face the disturbing phenomenon of the disappearance of honey bee colonies, termed Colony Collapse Disorder (CCD. One reason discussed is the possible suppression of honey bee immune system as a consequence of prolonged exposure to chemicals. In this study, the effects of the neonicotinoid thiamethoxam on honey bee, Apis mellifera carnica, pupae infested with Varroa destructor mites were analyzed at the molecular level. Varroa-infested and non-infested honey bee colonies received protein cakes with or without thiamethoxam. Nurse bees used these cakes as a feed for developing larvae. Samples of white-eyed and brown-eyed pupae were collected. Expression of 17 immune-related genes was analyzed by real-time PCR. Relative gene expression in samples exposed only to Varroa or to thiamethoxam or simultaneously to both Varroa and thiamethoxam was compared. The impact from the consumption of thiamethoxam during the larval stage on honey bee immune related gene expression in Varroa-infested white-eyed pupae was reflected as down-regulation of spaetzle, AMPs abaecin and defensin-1 and up-regulation of lysozyme-2. In brown-eyed pupae up-regulation of PPOact, spaetzle, hopscotch and basket genes was detected. Moreover, we observed a major difference in immune response to Varroa infestation between white-eyed pupae and brown-eyed pupae. The majority of tested immune-related genes were upregulated only in brown-eyed pupae, while in white-eyed pupae they were

  18. A Field Experiment to Assess the Rate of Infestation in Honey Bee Populations of Two Metarhizium Anisopliae Isolates on Varroa Destructor (Acari: Mesostigmata

    Directory of Open Access Journals (Sweden)

    Khodadad Pirali-kheirabadi

    2013-03-01

    Full Text Available Background: The protective effect of two isolates of an entomopathogenic fungus, Metarhizium anisopliae (DEMI 002 and Iran 437C on the adult stage of Varroa destructor was evaluated in comparison with fluvalinate strips in the field.Methods: A total of 12 honey bee colonies were provided from an apiculture farm. The selected hives were divided into 4 groups (3 hives per group. The first group was the control, treated with distilled water. The other two groups were exposed to different fungi (M. anisopliae isolates DEMI 002 and Iran 437C and the last group was treated with one strip of fluvalinate per colony. The number of fallen mites was counted using sticky traps during a 6-day period, six days before and after treatments. A fungal suspension at a concentration of 5× 106 conidia/mL was sprayed onto the frames and the number of fallen mites was counted.Results: Metarhizium anisopliae DEMI 002 and Iran 437C isolates were as effective (i.e., caused as much mite fall as the fluvalinate strip in controlling bee colonies than no treatment.Conclusion: Both M. anisopliae isolates are promising candidates as agents in the control of Varroa mites under field conditions. Isolate DEMI 002 can be considered as a possible non-chemical biocontrol agent for controlling bee infestation with V. destructor in the field. In order to substantiate this hypothesis, tests are currently being performed using larger colonies and larger doses than tested in the present study in our beekeeping.

  19. Impulso destructor: (SExperiencia perversa

    Directory of Open Access Journals (Sweden)

    José Miguel Viña Hernández

    2011-08-01

    Full Text Available Desde la Ilustración, la sexualidad ha quedado sometida a un discurso normativo. Aspectos como la pasión y el impulso se ven rígidamente constreñidos por esquemas morales y prejuicios heredados de una idiosincrasia aburguesada. Los intentos por esquivar y transgredir estos modelos han sido llevados a la pantalla, casi siempre bajo la tónica común del fracaso y la fatalidad. Desde Hitchcock a Pasolini, pasando por Truffaut o Kubrick, se trazará un recorrido cronológico, que estudia los ejemplos más paradigmáticos de la subversión erótica.

  20. Infestação do ácaro Varroa destructor em colônias de abelhas africanizadas (Apis mellifera L. no Semiárido potiguar, Nordeste do Brasil

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    Stephano Bismark Lopes Cavalcante Moreira

    2017-02-01

    Full Text Available O presente trabalho teve como objetivo analisar os índices de infestação pelo ácaro Varroa. destructor em colônias de abelhas africanizadas (Apis mellifera de apiários dos municípios de Encanto e de Marcelino Vieira, estado do Rio Grande do Norte. A pesquisa foi conduzida no período de setembro a dezembro de 2014, sendo coletadas em média de 100 a 200 abelhas adultas (nutrizes retiradas dos quadros centrais do ninho com crias de cada colmeia, aprisionadas em recipientes contendo 100 mL de álcool a 70% e encaminhadas para laboratório do Instituto Federal do Rio Grande do Norte (IFRN, para a contagem das abelhas e dos ácaros. Os resultados apresentaram ocorrência do ácaro V. destructor em todos apiários e em todas colmeias analisados, obtendo uma infestação média de 7,24% em Encanto e de 5,25% em Marcelino Vieira, níveis de infestação baixos (<15%, portanto, não acarretando risco às colônias.Varroa destructor mite infestation in colonies of Africanized honey bees (Apis mellifera L. in the potiguar Semi-arid region, Northeastern BrazilAbstract: The goal of the present work was to analyze the rates of infestation by Varroa. destructor mite in Africanized honeybees (Apis mellifera colonies from apiaries in Encanto and Marcelino Vieira cities, state of Rio Grande do Norte. The research was conducted during the period from September to December 2014. In average 100 to 200 adult bees (nursing honey bee workers were collected from the brood chamber over center frames of with brood of each hive surveyed, trapped in containers containing 100 mL of 70% alcohol and sent to the laboratory of the Federal Institute of Rio Grande do Norte (IFRN for the counting of bees and mites. The results showed an occurrence of the Varroa destructor mite in all apiaries and in all hives analyzed, obtaining an average infestation of 7.24% in Encanto city and 5.25% in Marcelino Vieira city, low infestation levels (<15%, without risk to the colonies.

  1. Infestation rate of the mite Varroa destructor in commercial apiaries of the Vale do Paraíba and Serra da Mantiqueira, southeastern Brazil

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    F.A. Pinto

    2015-04-01

    Full Text Available Nos últimos anos, grandes perdas de colônias de abelhas melíferas vêm sendo registradas em várias regiões do mundo. Contudo, os motivos desse acontecimento permanecem obscuros. O ácaro ectoparasita Varroa destructor Anderson e Trueman (Acari: Varroidae pode ser um dos responsáveis por esse fato, principalmente como vetor de vírus. Neste estudo, avaliaram-se as taxas de infestação (TIs do ácaro V. destructor em abelhas africanizadas Apis mellifera L. (Hymenoptera: Apidae e correlacionaram-se os dados com as médias de temperatura de 16 municípios das regiões do Vale do Paraíba e da Serra da Mantiqueira (São Paulo, Brasil, onde a apicultura comercial atua de maneira significativa. Em cada município, um apiário comercial foi selecionado para coleta de amostras de três colônias populosas (padrão Langstroth, totalizando 48 colônias amostradas. Aproximadamente 300 abelhas adultas localizadas na área de cria foram coletadas em cada colônia. As TIs variaram de 0.0 a 5.5%, níveis considerados baixos para causar danos significativos às colônias. As TIs mais baixas foram encontradas em municípios com clima mais ameno durante a estação avaliada (verão. Adicionalmente, cofatores como variações na disponibilidade de alimento entre os municípios e a variabilidade genética das abelhas podem interagir na interação entre parasita e hospedeiro. A variação nas TIs entre os municípios indica que, mesmo presente, a tolerância das abelhas africanizadas ao varroa pode variar drasticamente em uma pequena região, devido à dinâmica multifatorial de infestação do ácaro.

  2. Efecto del Fosfito de Potasio en Combinación con el Fungicida Metalaxyl + Mancozeb en el Control de Mildeo Velloso (Peronospora destructor Berk en Cebolla de Bulbo (Allium cepa L. Effect of the Potasium Phosphite in Combination with the Fungicide Metalaxyl plus Mancozeb on the Control of Downy Mildew (Peronospora destructor Berk in Onion Bulb (Allium cepa L.

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    Jorge Velandia Monsalve

    2012-06-01

    Full Text Available Resumen. El hongo Peronospora destructor causa considerables pérdidas en la producción de cebolla de bulbo en el mundo. Fosfito de potasio en combinación con el fungicida Metalaxyl + Mancozeb, fue evaluado por su eficiencia en el control de este patógeno en el híbrido de cebolla de bulbo Yellow Granex. Los tratamientos consistieron en una aplicación de fosfito (5 mL L-1 alternada con una de fungicida (2 g L-1; dos y tres aplicaciones consecutivas de fosfito alternadas con una de fungicida; una aplicación de fungicida alternada con una de fosfito; dos y tres aplicaciones consecutivas de fungicida alternadas con una de fosfito; aplicaciones de sólo fosfito y sólo fungicida y un testigo. Se utilizó el diseño experimental de bloques completos al azar con tres repeticiones. Se evaluó la incidencia y severidad de la enfermedad, el número, tamaño y peso de bulbos de primera, segunda, tercera y peso total de bulbos. Los resultados mostraron que las aplicaciones de fosfito de potasio durante dos semanas consecutivas alternadas en la tercera semana con una de fungicida y las aplicaciones semanales de sólo fosfito, tuvieron efectos altamente significativos en el control de la incidencia y severidad de P. destructor y diferencias significativas en el peso de los bulbos de primera (28,1 y 27,9 t ha-1 y peso total de bulbos (55,5 y 52,1 t ha-1, representando en relación al testigo, un incremento de 200 y 196% en el peso de los bulbos de primera y de 55 y 45,7% en el peso total de bulbos, respectivamente. Se concluye que con el fosfito de potasio se reduce la aplicación de fungicidas y ello es una alternativa viable para el manejo ecológico de P. destructor en la producción de cebolla de bulbo.Abstract. Peronospora destructor fungi causes considerable loses in the production of onion bulb in the world. Potassium phosphite in combination with the fungicide Metalaxyl + Mancozeb was evaluated for its efficiency in the control of this pathogen

  3. Relative abundance of deformed wing virus, Varroa destructor virus 1, and their recombinants in honey bees (Apis mellifera) assessed by kmer analysis of public RNA-Seq data

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    Cornman, Robert S.

    2017-01-01

    Deformed wing virus (DWV) is a major pathogen of concern to apiculture, and recent reports have indicated the local predominance and potential virulence of recombinants between DWV and a related virus, Varroa destructor virus 1 (VDV). However, little is known about the frequency and titer of VDV and recombinants relative to DWV generally. In this study, I assessed the relative occurrence and titer of DWV and VDV in public RNA-seq accessions of honey bee using a rapid, kmer-based approach. Three recombinant types were detectable graphically and corroborated by de novo assembly. Recombination breakpoints did not disrupt the capsid-encoding region, consistent with previous reports, and both VDV- and DWV-derived capsids were observed in recombinant backgrounds. High abundance of VDV kmers was largely restricted to recombinant forms. Non-metric multidimensional scaling identified genotypic clusters among DWV isolates, which was corroborated by read mapping and consensus generation. The recently described DWV-C lineage was not detected in the searched accessions. The data further highlight the utility of high-throughput sequencing to monitor viral polymorphisms and statistically test biological predictors of titer, and point to the need for consistent methodologies and sampling schemes.

  4. Toxicity of Selected Acaricides to Honey Bees (Apis mellifera) and Varroa (Varroa destructor Anderson and Trueman) and Their Use in Controlling Varroa within Honey Bee Colonies.

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    Gregorc, Aleš; Alburaki, Mohamed; Sampson, Blair; Knight, Patricia R; Adamczyk, John

    2018-05-10

    The efficacies of various acaricides in order to control a parasitic mite, the Varroa mite, Varroa destructor , of honey bees, were measured in two different settings, namely, in laboratory caged honey bees and in queen-right honey bee colonies. The Varroa infestation levels before, during, and after the acaricide treatments were determined in two ways, namely: (1) using the sugar shake protocol to count mites on bees and (2) directly counting the dead mites on the hive bottom inserts. The acaricides that were evaluated were coumaphos, tau-fluvalinate, amitraz, thymol, and natural plant compounds (hop acids), which were the active ingredients. The acaricide efficacies in the colonies were evaluated in conjunction with the final coumaphos applications. All of the tested acaricides significantly increased the overall Varroa mortality in the laboratory experiment. Their highest efficiencies were recorded at 6 h post-treatment, except for coumaphos and thymol, which exhibited longer and more consistent activity. In the honey bee colonies, a higher Varroa mortality was recorded in all of the treatments, compared with the natural Varroa mortality during the pretreatment period. The acaricide toxicity to the Varroa mites was consistent in both the caged adult honey bees and workers in the queen-right colonies, although, two of these acaricides, coumaphos at the highest doses and hop acids, were comparatively more toxic to the worker bees.

  5. Producción de miel e infestación con Varroa destructor de abejas africanizadas (Apis mellifera con alto y bajo comportamiento higiénico

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    Carlos Aurelio Medina-Flores

    2014-01-01

    Full Text Available El objetivo del estudio fue comparar la producción de miel y los niveles de Varroa destructor entre colonias de abejas africanizadas (AA ( Apis mellifera con alto y bajo comportamiento higiénico (CH en el altiplano semiárido de México. Se midió el nivel de CH a 57 colonias por congelamiento de la cría con nitrógeno líquido (N 2 . Las colonias se clasificaron en dos grupos: alto CH (> 95 % y bajo CH (0.05. Estos resultados sugieren que aparentemente el comportamiento higiénico no tiene un efecto mayor en la resistencia de las AA al crecimiento poblaci onal del ácaro. También sugieren que el comportamiento higiénico alto podría contribuir a incrementar la producción de miel en épocas del año con flujo reducido de néctar.

  6. Fertility and reproductive rate of Varroa mite, Varroa destructor, in native and exotic honeybee, Apis mellifera L., colonies under Saudi Arabia conditions

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    Yehya Alattal

    2017-07-01

    Full Text Available Varroa mite is the most destructive pest to bee colonies worldwide. In Saudi Arabia, preliminary data indicated high infestation levels in the exotic honeybee colonies; such as Apis mellifera carnica and Apis mellifera ligustica, compared to native honeybee subspecies Apis mellifera jemenitica, which may imply higher tolerance to Varroasis. In this study, fertility and reproductive rate of Varroa mite, Varroa destructor, in capped brood cells of the native honeybee subspecies were investigated and compared with an exotic honeybee subspecies, A. m. carnica. Mite fertility was almost alike (87.5% and 89.4% in the native and craniolan colonies respectively. Similarly, results did not show significant differences in reproduction rate between both subspecies (F = 0.66, Pr > F = 0.42. Number of adult Varroa daughters per fertile mother mite was 2.0 and 2.1 for native and craniolan honeybee subspecies respectively. This may indicate that mechanisms of keeping low infestation rates in the native honeybee colonies are not associated with Varroa reproduction. Therefore, potential factors of keeping lower Varroa infestation rates in native honey bee subspecies should be further investigated.

  7. A comparison of the reproductive ability of Varroa destructor (Mesostigmata:Varroidae) in worker and drone brood of Africanized honey bees (Apis mellifera).

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    Calderón, Rafael A; Zamora, Luis G; Van Veen, Johan W; Quesada, Mariela V

    2007-01-01

    Colony infestation by the parasitic mite, Varroa destructor is one of the most serious problems for beekeeping worldwide. In order to reproduce varroa females, enter worker or drone brood shortly before the cell is sealed. To test the hypothesis that, due to the preference of mites to invade drone brood to reproduce, a high proportion of the mite reproduction should occur in drone cells, a comparative study of mite reproductive rate in worker and drone brood of Africanized honey bees (AHB) was done for 370 mites. After determining the number, developmental stage and sex of the offspring in worker cells, the foundress female mite was immediately transferred into an uninfested drone cell. Mite fertility in single infested worker and drone brood cells was 76.5 and 79.3%, respectively. There was no difference between the groups (X(2)= 0.78, P = 0.37). However, one of the most significant differences in mite reproduction was the higher percentage of mites producing viable offspring (cells that contain one live adult male and at least one adult female mite) in drone cells (38.1%) compared to worker cells (13.8%) (X(2)= 55.4, P drone cells (X(2)= 69, P drone brood.

  8. Ratios of colony mass to thermal conductance of tree and man-made nest enclosures of Apis mellifera: implications for survival, clustering, humidity regulation and Varroa destructor

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    Mitchell, Derek

    2016-05-01

    In the absence of human intervention, the honeybee ( Apis mellifera L.) usually constructs its nest in a tree within a tall, narrow, thick-walled cavity high above the ground (the enclosure); however, most research and apiculture is conducted in the thin-walled, squat wooden enclosures we know as hives. This experimental research, using various hives and thermal models of trees, has found that the heat transfer rate is approximately four to seven times greater in the hives in common use, compared to a typical tree enclosure in winter configuration. This gives a ratio of colony mass to lumped enclosure thermal conductance (MCR) of less than 0.8 kgW-1 K for wooden hives and greater than 5 kgW-1 K for tree enclosures. This result for tree enclosures implies higher levels of humidity in the nest, increased survival of smaller colonies and lower Varroa destructor breeding success. Many honeybee behaviours previously thought to be intrinsic may only be a coping mechanism for human intervention; for example, at an MCR of above 2 kgW-1 K, clustering in a tree enclosure may be an optional, rare, heat conservation behaviour for established colonies, rather than the compulsory, frequent, life-saving behaviour that is in the hives in common use. The implied improved survival in hives with thermal properties of tree nests may help to solve some of the problems honeybees are currently facing in apiculture.

  9. Increased tolerance and resistance to virus infections: a possible factor in the survival of Varroa destructor-resistant honey bees (Apis mellifera.

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    Barbara Locke

    Full Text Available The honey bee ectoparasitic mite, Varroa destructor, has a world-wide distribution and inflicts more damage than all other known apicultural diseases. However, Varroa-induced colony mortality is more accurately a result of secondary virus infections vectored by the mite. This means that honey bee resistance to Varroa may include resistance or tolerance to virus infections. The aim of this study was to see if this is the case for a unique population of mite-resistant (MR European honey bees on the island of Gotland, Sweden. This population has survived uncontrolled mite infestation for over a decade, developing specific mite-related resistance traits to do so. Using RT-qPCR techniques, we monitored late season virus infections, Varroa mite infestation and honey bee colony population dynamics in the Gotland MR population and compared this to mite-susceptible (MS colonies in a close by apiary. From summer to autumn the deformed wing virus (DWV titres increased similarly between the MR and MS populations, while the black queen cell virus (BQCV and sacbrood virus (SBV titres decreased substantially in the MR population compared to the MS population by several orders of magnitude. The MR colonies all survived the following winter with high mite infestation, high DWV infection, small colony size and low proportions of autumn brood, while the MS colonies all perished. Possible explanations for these changes in virus titres and their relevance to Varroa resistance and colony winter survival are discussed.

  10. Genotypic variability and relationships between mite infestation levels, mite damage, grooming intensity, and removal of Varroa destructor mites in selected strains of worker honey bees (Apis mellifera L.).

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    Guzman-Novoa, Ernesto; Emsen, Berna; Unger, Peter; Espinosa-Montaño, Laura G; Petukhova, Tatiana

    2012-07-01

    The objective of this study was to demonstrate genotypic variability and analyze the relationships between the infestation levels of the parasitic mite Varroa destructor in honey bee (Apis mellifera) colonies, the rate of damage of fallen mites, and the intensity with which bees of different genotypes groom themselves to remove mites from their bodies. Sets of paired genotypes that are presumably susceptible and resistant to the varroa mite were compared at the colony level for number of mites falling on sticky papers and for proportion of damaged mites. They were also compared at the individual level for intensity of grooming and mite removal success. Bees from the "resistant" colonies had lower mite population rates (up to 15 fold) and higher percentages of damaged mites (up to 9 fold) than bees from the "susceptible" genotypes. At the individual level, bees from the "resistant" genotypes performed significantly more instances of intense grooming (up to 4 fold), and a significantly higher number of mites were dislodged from the bees' bodies by intense grooming than by light grooming (up to 7 fold) in all genotypes. The odds of mite removal were high and significant for all "resistant" genotypes when compared with the "susceptible" genotypes. The results of this study strongly suggest that grooming behavior and the intensity with which bees perform it, is an important component in the resistance of some honey bee genotypes to the growth of varroa mite populations. The implications of these results are discussed. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Evaluation of Metarhizium anisopliae var. anisopliae Qu-M845 Isolate to Control Varroa destructor (Acari: Varroidae in Laboratory and Field Trials Evaluación del Aislamiento Qu-M845 de Metarhizium anisopliae var. anisopliae para el Control de Varroa destructor (Acari: Varroidae en Ensayos de Laboratorio y Terreno

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    Marta Rodríguez

    2009-12-01

    Full Text Available The effectiveness of the Metarhizium anisopliae (Metschinkoff Qu-M845 isolate was evaluated in laboratory and field trials. It was previously selected for thermal resistance (at 30 and 35 ºC and pathogenicity on Varroa destructor (Anderson and Trueman. In the laboratory, the first evaluations were carried out by spraying and increasing the concentration from zero to 10(8 conidia mL-1 on varroa adults. Lethal concentrations required for 50 and 90% mite mortality (LC50 and LC90 were 3.8 x 10(5 and 8 x 10(7 conidia mL-1, respectively (χ2 = 2.03. In the autumn field trials, three application methods (doses of 5 x 10(10 conidia per hive were evaluated. The treatments were: a conidia stamped on filter paper, located on every second frame inside the hive; b dry conidia sprinkled on and between frames; and c dry conidia in a dispenser path at the entrance of the hive. Furthermore, untreated hives were included as controls. After 21 days of treatment, the dry conidia sprinkled on and between frames showed 67% less bees infested by the mite than the control (p La efectividad del aislamiento Qu-M845 de Metarhizium anisopliae (Metschinkoff, seleccionado previamente por su resistencia a temperaturas de 30 y 35 ºC, y patogenicidad sobre Varroa destructor Anderson y Trueman fue evaluada en laboratorio y en ensayos de terreno. Las primeras pruebas consistieron en pulverizar concentraciones crecientes de 0 a 10(8 conidias mL-1 sobre varroas adultas. La concentración letal para matar el 50 y 90% de la población (CL50 y CL90 fueron de 3,8 x 10(5 y 8 x 10(7 conidias mL-1, respectivamente (χ² = 2,03. En otoño se evaluaron en terreno tres métodos de aplicación de una dosis de 5 x 10(10 conidias por colmena. Los tratamientos fueron: a conidias estampadas en papel filtro ubicado cada dos panales móviles al interior de la colmena; b conidias espolvoreadas sobre y entre los panales; y c dispensador de conidias ubicado en la piquera de las colmenas. Además se

  12. A virulent strain of deformed wing virus (DWV of honeybees (Apis mellifera prevails after Varroa destructor-mediated, or in vitro, transmission.

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    Eugene V Ryabov

    2014-06-01

    Full Text Available The globally distributed ectoparasite Varroa destructor is a vector for viral pathogens of the Western honeybee (Apis mellifera, in particular the Iflavirus Deformed Wing Virus (DWV. In the absence of Varroa low levels DWV occur, generally causing asymptomatic infections. Conversely, Varroa-infested colonies show markedly elevated virus levels, increased overwintering colony losses, with impairment of pupal development and symptomatic workers. To determine whether changes in the virus population were due Varroa amplifying and introducing virulent virus strains and/or suppressing the host immune responses, we exposed Varroa-naïve larvae to oral and Varroa-transmitted DWV. We monitored virus levels and diversity in developing pupae and associated Varroa, the resulting RNAi response and transcriptome changes in the host. Exposed pupae were stratified by Varroa association (presence/absence and virus levels (low/high into three groups. Varroa-free pupae all exhibited low levels of a highly diverse DWV population, with those exposed per os (group NV exhibiting changes in the population composition. Varroa-associated pupae exhibited either low levels of a diverse DWV population (group VL or high levels of a near-clonal virulent variant of DWV (group VH. These groups and unexposed controls (C could be also discriminated by principal component analysis of the transcriptome changes observed, which included several genes involved in development and the immune response. All Varroa tested contained a diverse replicating DWV population implying the virulent variant present in group VH, and predominating in RNA-seq analysis of temporally and geographically separate Varroa-infested colonies, was selected upon transmission from Varroa, a conclusion supported by direct injection of pupae in vitro with mixed virus populations. Identification of a virulent variant of DWV, the role of Varroa in its transmission and the resulting host transcriptome changes furthers

  13. Are Dispersal Mechanisms Changing the Host-Parasite Relationship and Increasing the Virulence of Varroa destructor (Mesostigmata: Varroidae) in Managed Honey Bee (Hymenoptera: Apidae) Colonies?

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    DeGrandi-Hoffman, Gloria; Ahumada, Fabiana; Graham, Henry

    2017-08-01

    Varroa (Varroa destructor Anderson and Trueman) are a serious pest of European honey bees (Apis mellifera L.), and difficult to control in managed colonies. In our 11-mo longitudinal study, we applied multiple miticide treatments, yet mite numbers remained high and colony losses exceeded 55%. High mortality from varroa in managed apiaries is a departure from the effects of the mite in feral colonies where bees and varroa can coexist. Differences in mite survival strategies and dispersal mechanisms may be contributing factors. In feral colonies, mites can disperse through swarming. In managed apiaries, where swarming is reduced, mites disperse on foragers robbing or drifting from infested hives. Using a honey bee-varroa population model, we show that yearly swarming curtails varroa population growth, enabling colony survival for >5 yr. Without swarming, colonies collapsed by the third year. To disperse, varroa must attach to foragers that then enter other hives. We hypothesize that stress from parasitism and virus infection combined with effects that viruses have on cognitive function may contribute to forager drift and mite and virus dispersal. We also hypothesize that drifting foragers with mites can measurably increase mite populations. Simulations initialized with field data indicate that low levels of drifting foragers with mites can create sharp increases in mite populations in the fall and heavily infested colonies in the spring. We suggest new research directions to investigate factors leading to mite dispersal on foragers, and mite management strategies with consideration of varroa as a migratory pest. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.

  14. Population Growth of Varroa destructor (Acari: Varroidae) in Colonies of Russian and Unselected Honey Bee (Hymenoptera: Apidae) Stocks as Related to Numbers of Foragers With Mites.

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    DeGrandi-Hoffman, Gloria; Ahumada, Fabiana; Danka, Robert; Chambers, Mona; DeJong, Emily Watkins; Hidalgo, Geoff

    2017-06-01

    Varroa (Varroa destructor Anderson and Trueman) is an external parasite of honey bees (Apis mellifera L.) and a leading cause of colony losses worldwide. Varroa populations can be controlled with miticides, but mite-resistant stocks such as the Russian honey bee (RHB) also are available. Russian honey bee and other mite-resistant stocks limit Varroa population growth by affecting factors that contribute to mite reproduction. However, mite population growth is not entirely due to reproduction. Numbers of foragers with mites (FWM) entering and leaving hives also affect the growth of mite populations. If FWM significantly contribute to Varroa population growth, mite numbers in RHB colonies might not differ from unselected lines (USL). Foragers with mites were monitored at the entrances of RHB and USL hives from August to November, 2015, at two apiary sites. At site 1, RHB colonies had fewer FWM than USL and smaller phoretic mite populations. Russian honey bee also had fewer infested brood cells and lower percentages with Varroa offspring than USL. At site 2, FWM did not differ between RHB and USL, and phoretic mite populations were not significantly different. At both sites, there were sharp increases in phoretic mite populations from September to November that corresponded with increasing numbers of FWM. Under conditions where FWM populations are similar between RHB and USL, attributes that contribute to mite resistance in RHB may not keep Varroa population levels below that of USL. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.

  15. Impact of the Phoretic Phase on Reproduction and Damage Caused by Varroa destructor (Anderson and Trueman to Its Host, the European Honey Bee (Apis mellifera L..

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    Vincent Piou

    Full Text Available Varroa destructor is a parasitic mite of the honeybee that causes thousands of colony losses worldwide. The parasite cycle is composed of a phoretic and a reproductive phase. During the former, mites stay on adult bees, mostly on nurses, to feed on hemolymph. During the latter, the parasites enter brood cells and reproduce. We investigated if the type of bees on which Varroa stays during the phoretic phase and if the duration of this stay influenced the reproductive success of the parasite and the damage caused to bees. For that purpose, we used an in vitro rearing method developed in our laboratory to assess egg laying rate and the presence and number of fully molted daughters. The expression level of two Varroa vitellogenin genes (VdVg1 and VdVg2, known to vary throughout reproduction, was also quantified. Results showed that the status of the bees or time spent during the phoretic phase impacts neither reproduction parameters nor the Varroa vitellogenin genes levels of expression. However, we correlated these parameters to the gene expression and demonstrated that daughters expressed the vitellogenin genes at lower levels than their mother. Regarding the damage to bees, the data indicated that a longer stay on adult bees during the phoretic phase resulted in more frequent physical deformity in newborn bees. We showed that those mites carry more viral loads of the Deformed Wing Virus and hence trigger more frequently overt infections. This study provides new perspectives towards a better understanding of the Varroa-honeybee interactions.

  16. Comparative molecular analyses of select pH- and osmoregulatory genes in three freshwater crayfish Cherax quadricarinatus, C. destructor and C. cainii

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    Muhammad Y. Ali

    2017-08-01

    Full Text Available Systemic acid-base balance and osmotic/ionic regulation in decapod crustaceans are in part maintained by a set of transport-related enzymes such as carbonic anhydrase (CA, Na+/K+-ATPase (NKA, H+-ATPase (HAT, Na+/K+/2Cl− cotransporter (NKCC, Na+/Cl−/HCO ${}_{3}^{-}$ 3 − cotransporter (NBC, Na+/H+ exchanger (NHE, Arginine kinase (AK, Sarcoplasmic Ca+2-ATPase (SERCA and Calreticulin (CRT. We carried out a comparative molecular analysis of these genes in three commercially important yet eco-physiologically distinct freshwater crayfish, Cherax quadricarinatus, C. destructor and C. cainii, with the aim to identify mutations in these genes and determine if observed patterns of mutations were consistent with the action of natural selection. We also conducted a tissue-specific expression analysis of these genes across seven different organs, including gills, hepatopancreas, heart, kidney, liver, nerve and testes using NGS transcriptome data. The molecular analysis of the candidate genes revealed a high level of sequence conservation across the three Cherax sp. Hyphy analysis revealed that all candidate genes showed patterns of molecular variation consistent with neutral evolution. The tissue-specific expression analysis showed that 46% of candidate genes were expressed in all tissue types examined, while approximately 10% of candidate genes were only expressed in a single tissue type. The largest number of genes was observed in nerve (84% and gills (78% and the lowest in testes (66%. The tissue-specific expression analysis also revealed that most of the master genes regulating pH and osmoregulation (CA, NKA, HAT, NKCC, NBC, NHE were expressed in all tissue types indicating an important physiological role for these genes outside of osmoregulation in other tissue types. The high level of sequence conservation observed in the candidate genes may be explained by the important role of these genes as well as potentially having a number of other basic

  17. Comparative molecular analyses of select pH- and osmoregulatory genes in three freshwater crayfish Cherax quadricarinatus, C. destructor and C. cainii.

    Science.gov (United States)

    Ali, Muhammad Y; Pavasovic, Ana; Dammannagoda, Lalith K; Mather, Peter B; Prentis, Peter J

    2017-01-01

    Systemic acid-base balance and osmotic/ionic regulation in decapod crustaceans are in part maintained by a set of transport-related enzymes such as carbonic anhydrase (CA), Na + /K + -ATPase (NKA), H + -ATPase (HAT), Na + /K + /2Cl - cotransporter (NKCC), Na + /Cl - /HCO[Formula: see text] cotransporter (NBC), Na + /H + exchanger (NHE), Arginine kinase (AK), Sarcoplasmic Ca +2 -ATPase (SERCA) and Calreticulin (CRT). We carried out a comparative molecular analysis of these genes in three commercially important yet eco-physiologically distinct freshwater crayfish , Cherax quadricarinatus, C. destructor and C. cainii , with the aim to identify mutations in these genes and determine if observed patterns of mutations were consistent with the action of natural selection. We also conducted a tissue-specific expression analysis of these genes across seven different organs, including gills, hepatopancreas, heart, kidney, liver, nerve and testes using NGS transcriptome data. The molecular analysis of the candidate genes revealed a high level of sequence conservation across the three Cherax sp. Hyphy analysis revealed that all candidate genes showed patterns of molecular variation consistent with neutral evolution. The tissue-specific expression analysis showed that 46% of candidate genes were expressed in all tissue types examined, while approximately 10% of candidate genes were only expressed in a single tissue type. The largest number of genes was observed in nerve (84%) and gills (78%) and the lowest in testes (66%). The tissue-specific expression analysis also revealed that most of the master genes regulating pH and osmoregulation (CA, NKA, HAT, NKCC, NBC, NHE) were expressed in all tissue types indicating an important physiological role for these genes outside of osmoregulation in other tissue types. The high level of sequence conservation observed in the candidate genes may be explained by the important role of these genes as well as potentially having a number of

  18. Estudio sobre la Eficacia a Campo del Amivar® contra Varroa destructor (Mesostigmata: Varroidae en Colmenas de Apis mellifera (Hymenoptera: Apidae

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    Jorge MARCANGELI

    2005-01-01

    Full Text Available El objetivo del trabajo fue evaluar la eficacia del producto Amivar® para el control del ácaro Varroa destructor Anderson & Trueman, en colmenas de abejas durante el otoño de 2003. El trabajo se llevó a cabo en el apiario experimental del Centro de Extensión Apícola ubicado en Coronel Vidal, provincia de Buenos Aires. Se trabajó sobre un total de 20 colmenas tipo Langstroth que se dividieron en dos grupos iguales. En el primer grupo se introdujo una tira de Amivar® (amitraz, 1gr, Apilab, Argentina en el centro del nido de cría de las colmenas. El segundo grupo, sólo recibió el tratamiento de Oxavar® para determinar el número total de ácaros presentes en las colmenas. Semanalmente, se recolectaron los ácaros muertos caídos en pisos especiales que evitaban que las abejas los eliminen. Posteriormente, los dos grupos recibieron tres dosis en total a intervalos de siete días de 5 ml del producto Oxavar® (Apilab-INTA, Argentina; 64,6 g/l; ácido oxálico en agua destilada por cuadro cubierto por abejas para eliminar los ácaros remanentes en las colonias y poder así calcular la eficacia del tratamiento. El producto Amivar® presentó una eficacia promedio de 85,05% ± 3,39 (rango = 79,5 – 91,6, registrándose diferencias significativas frente al grupo control (p< 0,05. No seobservaron efectos negativos del producto sobre la cría de abejas en desarrollo. Estos resultados demuestran que este producto es efectivo para el control de la parasitosis.

  19. Varroa destructor Macula-like virus, Lake Sinai virus and other new RNA viruses in wild bumblebee hosts (Bombus pascuorum, Bombus lapidarius and Bombus pratorum).

    Science.gov (United States)

    Parmentier, Laurian; Smagghe, Guy; de Graaf, Dirk C; Meeus, Ivan

    2016-02-01

    Pollinators such as bumblebees (Bombus spp.) are in decline worldwide which poses a threat not only for ecosystem biodiversity but also to human crop production services. One main cause of pollinator decline may be the infection and transmission of diseases including RNA viruses. Recently, new viruses have been discovered in honeybees, but information on the presence of these in wild bumblebees is largely not available. In this study, we investigated the prevalence of new RNA viruses in Bombus species, and can report for the first time Varroa destructor Macula-like virus (VdMLV) and Lake Sinai virus (LSV) infection in multiple wild bumblebee hosts of Bombus pascuorum, Bombus lapidarius and Bombus pratorum. We sampled in 4 locations in Flanders, Belgium. Besides, we confirmed Slow bee paralysis virus (SBPV) in wild bumblebees, but no positive samples were obtained for Big Sioux river virus (BSRV). Secondly, we screened for the influence of apiaries on the prevalence of these viruses. Our results indicated a location effect for the prevalence of VdMLV in Bombus species, with a higher prevalence in the proximity of honeybee apiaries mainly observed in one location. For LSV, the prevalence was not different in the proximity or at a 1.5 km-distance of apiaries, but we reported a different isolate with similarities to LSV-2 and "LSV-clade A" as described by Ravoet et al. (2015), which was detected both in Apis mellifera and Bombus species. In general, our results indicate the existence of a disease pool of new viruses that seems to be associated to a broad range of Apoidae hosts, including multiple Bombus species. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Varroa destructor mite mortality rate according to the amount of worker broods in africanized honey bee (Apis mellifera L. colonies = Taxa de mortalidade do ácaro Varroa destructor de acordo com a quantidade de crias em colônias de abelhas africanizadas (Apis mellifera L.

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    Geraldo Moretto

    2007-07-01

    Full Text Available The Varroa destructor mite has caused the death of hundreds of thousands of Apis mellifera colonies in several countries worldwide. However, the effects determined by the Varroa mite change according to the A. mellifera subspecies. In Africanized bee colonies from South and Central America, the parasite causes little damage, as the infestation levels are relatively stable and low, thus treatments against the pest are not required. Among several factors, the grooming behavior of Africanized worker bees plays an important role in the maintenance of the low infestation levels. This study determined the daily rate of live and dead mites found at the bottom of the hive in five Africanized honey bee colonies. During fifteen days of observations, a significant increase was verified in the number of live and dead mites at the bottom of the hive as the amount of worker broods from each honey bee colony decreased. This suggests a more intense grooming activity as the Varroa concentration in the adult honey bee population increases.O ácaro Varroa destructor tem causado a mortalidade de centenas de milhares de colônias de abelhas Apis mellifera em várias partes do mundo. Os efeitos determinados pelo ácaro Varroa variam com a subespécie de Apis mellifera. Nas Américas do Sul e Central, o parasita causa poucos danos às colônias de abelhas africanizadas, a taxa de infestação é estável e baixa, não sendo necessário o tratamento químico contra a praga. Entre vários fatores que são responsáveis pela tolerância das abelhas africanizadas a esse parasita, o comportamento de grooming executado pelas operárias deve exercer importante papel na manutenção dos baixos níveis deinfestação. Neste estudo, foram avaliadas as taxas diárias de ácaros vivos e mortos encontrados no fundo das colméias de cinco colônias de abelhas africanizadas. Durante 15 dias de observações, foi verificado significativo aumento de ácaros no fundo da colméia

  1. Control del Ácaro Varroa destructor (Mesostigmata: Varroidae en Colmenas de Apis mellifera (Hymenoptera: Apidae mediante la Aplicación de distintos Principios Activos Control of Varroa destructor (Mesostigmata: Varroidae in honeybee colonies of Apis mellifera Hymenoptera: Apidae by means of different active agents

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    Jorge Augusto Marcangeli

    2003-12-01

    Full Text Available El objetivo de este trabajo fue evaluar la eficacia acaricida de cuatro productos utilizados para el control del ácaro Varroa destructor (Anderson & Trueman en colmenas de Apis mellifera (L.. Se seleccionaron 25 colmenas dividivas en cinco lotes iguales a las que se les suministró Apistan®, Bayvarol®, Apitol® y Folbex®. El último lote representó el control. Los ácaros muertos se recolectaron en pisos especiales que se controlaron semanalmente. Finalizada la experiencia cada lote fue sometido a un cruzamiento con otros productos con el fin de eliminar los ácaros remanentes y poder calcular las eficacias. El producto Apistan® fue el más efectivo con un valor promedio de 85,38% seguido por el Bayvarol® (83,83%, Apitol® (71,77% y Folbex® (62,78%. En todos los casos, los valores obtenidos resultaron inferiores a los estipulados por los laboratorios productores. Estos resultados alertan sobre la posible generación de resistencias por parte de las poblaciones del ácaro y la necesidad de buscar nuevos agentes de control eficaces para esta enfermedad.The aim of this work was to evaluate the acaricide efficacy of four commercial products against the mite Varroa destructor (Anderson & Trueman in honeybee colonies of Apis mellifera (L.. Twenty five honeybee colonies divided in five equal groups were selected. Groups received Apistan®, Bayvarol®, Apitol® and Folbex®. Final group was the control. Dead mites were collected weekly in special floors. After treatment, each colony received a shock treatment with the other three products to kill remnant mites and to obtain acaricide efficacy. Average values of efficacy were Apistan® 85,38%, Bayvarol® 83,83%, Apitol® 71,77% and Folbex® 62,78%. In all cases these values were lower than those reported by the laboratories that produce them. These results alert about the possible generation of resistant mite populations and justify research directed to search for alternative products for the

  2. Lower virus infections in Varroa destructor-infested and uninfested brood and adult honey bees (Apis mellifera) of a low mite population growth colony compared to a high mite population growth colony.

    Science.gov (United States)

    Emsen, Berna; Hamiduzzaman, Mollah Md; Goodwin, Paul H; Guzman-Novoa, Ernesto

    2015-01-01

    A comparison was made of the prevalence and relative quantification of deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), black queen cell virus (BQCV), Kashmir bee virus (KBV), acute bee paralysis virus (ABPV) and sac brood virus (SBV) in brood and adult honey bees (Apis mellifera) from colonies selected for high (HMP) and low (LMP) Varroa destructor mite population growth. Two viruses, ABPV and SBV, were never detected. For adults without mite infestation, DWV, IAPV, BQCV and KBV were detected in the HMP colony; however, only BQCV was detected in the LMP colony but at similar levels as in the HMP colony. With mite infestation, the four viruses were detected in adults of the HMP colony but all at higher amounts than in the LMP colony. For brood without mite infestation, DWV and IAPV were detected in the HMP colony, but no viruses were detected in the LMP colony. With mite infestation of brood, the four viruses were detected in the HMP colony, but only DWV and IAPV were detected and at lower amounts in the LMP colony. An epidemiological explanation for these results is that pre-experiment differences in virus presence and levels existed between the HMP and LMP colonies. It is also possible that low V. destructor population growth in the LMP colony resulted in the bees being less exposed to the mite and thus less likely to have virus infections. LMP and HMP bees may have also differed in susceptibility to virus infection.

  3. Toxicity of Anethole and the Essential Oils of Lemongrass and Sweet Marigold to the Parasitic Mite Varroa destructor and Their Selectivity for Honey Bee (Apis mellifera Workers and Larvae

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    Qodratollah Sabahi

    2018-01-01

    Full Text Available This study examined the toxicity of anethole and that of the essential oils of lemongrass (Cymbopogon citratus and sweet marigold (Tagetes lucida to the mite Varroa destructor and to honey bee workers and larvae. Anethole was the most toxic compound to V. destructor (LC50: 304.9 μg/ml, whereas Tagetes oil was the least toxic (LC50: 1256.27 μg/ml. The most and least toxic compounds to worker bees were anethole and Tagetes oil with LD50s of 35942 and 85381 μg/ml, respectively. For larvae, Tagetes oil was the most toxic compound (LD50: 9580.7 μg/ml and anethole the least toxic (LD50: 14518.0 μg/ml. Anethole and Cymbopogon oil had the highest selectivity ratios. The expression of AChE, a gene that regulates the production of acetyl cholinesterase, a detoxifying enzyme, was not altered in bees treated with the plant compounds at 48 h post-treatment. This study showed that anethole and Cymbopogon oil have potential for controlling Varroa mites and seem to be relatively safe for larvae and adult honey bees.

  4. Lower Virus Infections in Varroa destructor-Infested and Uninfested Brood and Adult Honey Bees (Apis mellifera) of a Low Mite Population Growth Colony Compared to a High Mite Population Growth Colony

    Science.gov (United States)

    Emsen, Berna; Hamiduzzaman, Mollah Md.; Goodwin, Paul H.; Guzman-Novoa, Ernesto

    2015-01-01

    A comparison was made of the prevalence and relative quantification of deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), black queen cell virus (BQCV), Kashmir bee virus (KBV), acute bee paralysis virus (ABPV) and sac brood virus (SBV) in brood and adult honey bees (Apis mellifera) from colonies selected for high (HMP) and low (LMP) Varroa destructor mite population growth. Two viruses, ABPV and SBV, were never detected. For adults without mite infestation, DWV, IAPV, BQCV and KBV were detected in the HMP colony; however, only BQCV was detected in the LMP colony but at similar levels as in the HMP colony. With mite infestation, the four viruses were detected in adults of the HMP colony but all at higher amounts than in the LMP colony. For brood without mite infestation, DWV and IAPV were detected in the HMP colony, but no viruses were detected in the LMP colony. With mite infestation of brood, the four viruses were detected in the HMP colony, but only DWV and IAPV were detected and at lower amounts in the LMP colony. An epidemiological explanation for these results is that pre-experiment differences in virus presence and levels existed between the HMP and LMP colonies. It is also possible that low V. destructor population growth in the LMP colony resulted in the bees being less exposed to the mite and thus less likely to have virus infections. LMP and HMP bees may have also differed in susceptibility to virus infection. PMID:25723540

  5. A Toolbox for Quantitative Gene Expression in Varroa destructor: RNA Degradation in Field Samples and Systematic Analysis of Reference Gene Stability.

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    Ewan M Campbell

    Full Text Available Varroa destructor is the major pest of Apis mellifera and contributes to the global honey bee health crisis threatening food security. Developing new control strategies to combat Varroa will require the application of molecular biology, including gene expression studies by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR. Both high quality RNA samples and suitable stable internal reference genes are required for accurate gene expression studies. In this study, ten candidate genes (succinate dehydrogenase (SDHA, NADH dehydrogenase (NADH, large ribsosmal subunit, TATA-binding protein, glyceraldehyde-3-phosphate dehydrogenase, 18S rRNA (18S, heat-shock protein 90 (HSP90, cyclophilin, α-tubulin, actin, were evaluated for their suitability as normalization genes using the geNorm, Normfinder, BestKeeper, and comparative ΔCq algorithims. Our study proposes the use of no more than two of the four most stable reference genes (NADH, 18S, SDHA and HSP90 in Varroa gene expression studies. These four genes remain stable in phoretic and reproductive stage Varroa and are unaffected by Deformed wing virus load. When used for determining changes in vitellogenin gene expression, the signal-to-noise ratio (SNR for the relatively unstable genes actin and α-tubulin was much lower than for the stable gene combinations (NADH + HSP90 +18S; NADH + HSP90; or NADH. Using both electropherograms and RT-qPCR for short and long amplicons as quality controls, we demonstrate that high quality RNA can be recovered from Varroa up to 10 days later stored at ambient temperature if collected into RNAlater and provided the body is pierced. This protocol allows the exchange of Varroa samples between international collaborators and field sample collectors without requiring frozen collection or shipping. Our results make important contributions to gene expression studies in Varroa by proposing a validated sampling protocol to obtain high quality Varroa

  6. Evaluación de la resistencia del ácaro Varroa destructor al fluvalinato en colonias de abejas (Apis mellifera en Yucatán, México

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    Jesús Froylán Martínez Puc

    2011-01-01

    Full Text Available La constante aplicación de piretroides para el control del ácaro Varroa destructor ha ocasionado la aparición de poblaciones de ácaros resistentes a este producto en diversas partes del mundo. Con la finalidad de detectar la posible existencia de poblaciones de ácaros resistentes al fluvalinato en el estado de Yucatán, uno de los principales estados productores de miel en México, se colectó un total de 12 muestras por cada apiario, seleccionando cuatro apiarios donde se ha utilizado de manera constante el fluvalinato para el control de V. destructor por un periodo de cinco años, y una cantidad de muestras similar provenientes de apiarios donde se han utilizado métodos de control alternativo durante un tiempo similar. Para determinar el porcentaje de mortalidad de los ácaros al fluvalinato, estos fueron expuestos a una pieza de 2.5 x 1.0 cm de Apistan® al 10%, por un periodo de 24 h. El porcentaje de mortalidad de varroas provenientes de apiarios tratados de manera constante con fluvalinato fue de 83.6 ± 0.51 %, inferior al porcentaje de mortalidad obtenido en los apiarios que sólo han recibido tratamiento alternativo el cual fue de 93.9 ± 1.98 %, existiendo diferencias entre ambos grupos (t=-3.93, P=0.01, gl= 46, lo cual indica una reducción en el porcentaje de mortalidad obtenido con el fluvalinato, sin embargo, esta reducción, aun no alcanza los niveles necesarios para reportar la presencia de ácaros resistentes, siendo importante cambiar las prácticas de manejo encaminadas a reducir los niveles de infestación de V. destructor, por lo que es recomendable la aplicación de métodos de control alternativo los cuales no ocasionan el desarrollo de resistencia en las poblaciones de ácaros.

  7. Efecto de la cantidad de cría de abeja Apis mellifera (Apidae sobre la eficacia del Oxavar® para el control del ácaro Varroa destructor (Varroidae Effect of Apis mellifera (Apidae honeybee brood amount on Oxavar® acaricide efficacy against the mite Varroa destructor (Varroidae

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    Jorge Marcangeli

    2004-12-01

    Full Text Available El objetivo del presente trabajo fue evaluar la eficacia acaricida del Oxavar® en el control del ácaro ectoparásito Varroa destructor (Anderson & Trueman. El trabajo fue realizado en el apiario experimental del Centro de Extensión Apícola ubicado en Coronel Vidal, provincia de Buenos Aires. Se seleccionaron diez colmenas tipo Langstroth que fueron divididas en dos grupos: a cinco colmenas con tres cuadros cubiertos completamente de cría en desarrollo y b cinco colmenas con seis cuadros cubiertos por cría. Ambos grupos recibieron cinco ml of Oxavar® (Apilab, Argentina; 64,6 g/l de ácido oxálico en agua destilada por cuadro cubierto por abejas adultas en tres dosis a intervalos de siete días. Semanalmente, se colectaron los ácaros muertos de los pisos especiales provistos a las colmenas de estudio con el objeto de evitar su remoción por parte de las abejas. Una vez concluido el tratamiento, en cada colmena se introdujeron dos tiras plásticas de Apistan® (Roteh, Argentina para eliminar los ácaros remanentes y poder así calcular la eficacia acaricida del Oxavar®. Los resultados mostraron que la eficacia del Oxavar® en el primer grupo (85,6% ± 1,4 resultó significativamente superior a la registrada en el segundo grupo (75,7 ± 1,7. Estas diferencias fueron testeadas a partir del número total de ácaros eliminados por el Oxavar® y Apistan® en ambos grupos de colmenas (pThe aim of this work was to evaluate the effect of honeybee brood on acaricide efficacy of Oxavar® to control the ectoparasitic mite Varroa destructor (Anderson & Trueman. Work was done at Centro de Extensión Apícola experimental apiary located at Coronel Vidal, province of Buenos Aires. Ten Langstroth hives were selected and divided in two groups: a hives containing three honeybee combs full of brood and b hives containing six honeybee brood combs. Both groups received five ml of Oxavar® (Laboratorio Apilab, Argentina; 64.6 g/l oxalic acid in destilled water

  8. Estudio sobre la Eficacia a Campo del Amivar® contra Varroa destructor (Mesostigmata: Varroidae en Colmenas de Apis mellifera (Hymenoptera: Apidae Research on Amivar® efficacy against Varroa destructor (Mesostigmata: Varroidae in honey bee colonies of Apis mellifera (Hymenoptera: Apidae

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    Jorge Marcangeli

    2005-07-01

    Full Text Available El objetivo del trabajo fue evaluar la eficacia del producto Amivar® para el control del ácaro Varroa destructor Anderson & Trueman, en colmenas de abejas durante el otoño de 2003. El trabajo se llevó a cabo en el apiario experimental del Centro de Extensión Apícola ubicado en Coronel Vidal, provincia de Buenos Aires. Se trabajó sobre un total de 20 colmenas tipo Langstroth que se dividieron en dos grupos iguales. En el primer grupo se introdujo una tira de Amivar® (amitraz, 1gr, Apilab, Argentina en el centro del nido de cría de las colmenas. El segundo grupo, sólo recibió el tratamiento de Oxavar® para determinar el número total de ácaros presentes en las colmenas. Semanalmente, se recolectaron los ácaros muertos caídos en pisos especiales que evitaban que las abejas los eliminen. Posteriormente, los dos grupos recibieron tres dosis en total a intervalos de siete días de 5 ml del producto Oxavar® (Apilab-INTA, Argentina; 64,6 g/l; ácido oxálico en agua destilada por cuadro cubierto por abejas para eliminar los ácaros remanentes en las colonias y poder así calcular la eficacia del tratamiento. El producto Amivar® presentó una eficacia promedio de 85,05%±3,39 (rango=79,5 91,6, registrándose diferencias significativas frente al grupo control (pThe aim of this work was to evaluate the acaricide efficacy of Amivar® (amitraz, Apilab, Argentina to control Varroa destructor Anderson & Trueman, in Apis mellifera colonies during the autumn 2003. Work was done at "Centro de Extensión Apícola" experimental apiary located in Coronel Vidal, province of Buenos Aires. Twenty Langstroth hives were used divided in two equal groups. The first group received one strip of Amivar® (amitraz, 1 gr in the center of brood area. The second one represented the control group. Dead mites were collected weekly from special floors designed to avoid mite removal by adult honeybees. Then, a total of three doses of 5 ml of Oxavar® at seven days

  9. Ensayo a campo sobre la eficacia del Colmesan® contra el ácaro Varroa destructor (Varroidae en colmenas de Apis mellifera (Apidae Field assay of Colmesan® efficacy against the mite Varroa destructor (Varroidae in honey bee colonies of Apis mellifera (Apidae

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    Jorge Marcangeli

    2004-12-01

    Full Text Available El objetivo del trabajo fue evaluar la eficacia del producto Colmesan® para el control del ácaro Varroa destructor (Anderson &Trueman en colmenas de abejas durante el otoño de 2003. El trabajo se llevó a cabo en el apiario experimental ubicado en la ciudad de La Plata, provincia de Buenos Aires. Se trabajó sobre un total de 10 colmenas tipo "Langstroth" que se dividieron en dos grupos iguales. El primer grupo recibió dos dosis de Colmesan® (amitraz, 2,05 g, aplicadas a intervalos de 10 días. El segundo grupo, no recibió ningún tipo de tratamiento. Semanalmente, se recolectaron los ácaros muertos caídos en pisos especiales que evitaban que las abejas los eliminen. Posteriormente, los dos grupos recibieron tres dosis semanales de 5 ml del producto Oxavar® (64,6g/l ácido oxálico en agua destilada por cuadro cubierto por abejas para eliminar los ácaros remanentes en las colonias y poder así calcular la eficacia del tratamiento. El producto Colmesan® presentó una eficacia promedio de 70,92% ± 11,93 (rango = 57,92 - 85,42, registrándose diferencias significativas frente al grupo control (pThe aim of this work was to evaluate the acaricide efficacy of Colmesan® to control Varroa destructor (Anderson & Trueman in Apis mellifera (L. colonies during the autumn 2003. Work was done at an experimental apiary located in La Plata city, province of Buenos Aires. Ten Langstroth hives were used divided in two equal groups. The first group received Colmesan® (amitraz, 2,05 g in 2 doses at 10 days period. The second one represented the control group. Dead mites were collected weekly from special floors designed to avoid mite removal by adult honeybees. Then, 3 weekly doses of 5 ml of Oxavar® (64.6 g/l oxalic acid in destilled water were placed in each colony to kill remanent mites and the acaricide efficacy was calculated. Colmesan® showed an average acaricide efficacy of 70.92% ± 11.93 (range = 57.92 -85.42, showing significant

  10. Hessian Fly, Mayetiola destructor (Say, Populations in the North of Tunisia: Virulence, Yield Loss Assessment and Phenological Data Poblaciones de Mosca de Hess, Mayetiola destructor (Say, en el Norte de Túnez: Virulencia, Evaluación de Pérdida de Producción y Datos Fenológicos

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    Hanem Makni

    2011-09-01

    Full Text Available Hessian fly, Mayetiola destructor (Say, is a destructive pest of wheat worldwide and an endemic pest in Tunisia. Two natural populations of this insect from the North of Tunisia were evaluated, in the field, for their virulence, based on response developed by bread wheat (Triticum aestivum L. cultivars carrying H3, H5, H6, H7H8, H11, H13 and H16 resistance genes. H11, H13 and H16 showed a high effectiveness against both populations; therefore, their implication in Hessian fly breeding programs would be of interest. The level of infestation, as well as the yield loss, was assessed, based on the percentage of infested plants and variation in growth parameters due to infestation. The percentage of infested plants, over a 2-yr period in Mateur, averaged 18.82% for durum wheat (Triticum turgidum L. subsp. durum (Desf. Husn. and 32.50% for bread wheat. For the improved durum wheat cv. Karim used as reference, the plant height, number of internodes, number of productive tillers per plant, and 100-seed weight were negatively affected by infestation, while the number of tillers per plant was positively affected. Aiming to update information about the annual number of the fly generations occurring on wheat, we surveyed infestation in Jédéida. At least three Hessian fly generations were detected on bread wheat and durum wheat. Continued regular surveying of Hessian fly populations in terms of virulence, impact on yield and annual generations is required for optimal deployment of resistance genes and integrated management of Hessian fly across all wheat production areas.La mosca de Hess, Mayetiola destructor (Say, es una plaga mundial destructiva del trigo y endémica en Túnez. Se evaluaron dos poblaciones naturales de este insecto desde el Norte de Túnez, en el campo, por su virulencia, basado en la respuesta desarrollada por cultivares de trigo panadero (Triticum aestivum L. portando los genes de resistencia H3, H5, H6, H7H8, H11, H13 y H16. H11, H13

  11. Control del parásito Varroa destructor (Acari: Varroidae en colmenas de la abeja Apis mellifera (Hymenoptera: Apidae mediante la aplicación de la técnica de entrampado Control of the parasite Varroa destructor (Acari: Varroidae in honeybee colonies of Apis mellifera (Hymenoptera: Apidae applying brood trap combs

    Directory of Open Access Journals (Sweden)

    Natalia Damiani

    2006-07-01

    Full Text Available La parasitosis causada por el ácaro Varroa destructor (Anderson & Trueman es, actualmente considerada el mayor escollo para el desarrollo de la apicultura. El objetivo del presente trabajo fue evaluar la técnica del entrampamiento de ácaros en panales de cría, como posible método de control de la parasitosis. El trabajo se llevó a cabo en Coronel Vidal, provincia de Buenos Aires. Se trabajó sobre colmenas tipo Langstroth del híbrido regional de Apis mellifera (Linneaus. En cada colmena experimental se procedió a confinar a la reina en panales trampa específicos, con el fin de poder controlar la oviposición. Estos panales, luego de ser operculados por las obreras, fueron llevados al laboratorio donde se desoperculó cada una de las celdas de cría, y se contabilizó el número de ácaros presentes. Esta técnica se aplicó variando el número de panales trampa (1-3 colocados, tanto para los constituidos por celdas de cría de obreras como de zánganos. También, se evaluó el impacto de la aplicación de esta técnica sobre el desarrollo de las colonias, mediante la medición de su productividad. Los resultados indican, que la técnica empleada sólo es efectiva, cuando se aplican tres panales de cría de zánganos de manera consecutiva, alcanzando una efectividad máxima de 84%. Cuando se aplican tres panales de obreras, la técnica mostró niveles de efectividad muy inferiores (14%. En las colonias sobre las que se aplicó esta técnica, la productividad de miel se redujo significativamente, comparada con las colonias control. Esta técnica resulta ideal para ser combinada con otros mecanismos de control, disminuyendo la aplicación de sustancias químicas que puedan contaminar la miel, y la generación de resistencia por parte del ácaro frente a los principios activos utilizados para su control.At present, Varroosis is considered the major problem to beekeeping development. The aim of this work was to evaluate brood tramp combs

  12. Índices de prevalencia del ácaro Varroa destructor (Acari: Varroidae en cuadros de cría nuevos o previamente utilizados por Apis mellifera (Hymenoptera: Apidae Infestation levels of the mite Varroa destructor (Acari: Varroidae in new and old honeybee brood combs of Apis mellifera (Hymenoptera: Apidae

    Directory of Open Access Journals (Sweden)

    Jorge, A. Marcangeli

    2007-07-01

    Full Text Available El objetivo de esta investigación fue comparar los niveles de infestación de Varroa destructor (Anderson & Trueman en panales de cría nuevos y viejos, en colonias de la abeja criolla (híbrido de Apis mellifera mellifera (Linnaeus y Apis mellifera ligustica Spinola. El trabajo se llevó a cabo en un apiario ubicado en Coronel Vidal, provincia de Buenos Aires, durante la primavera del año 2005. Se trabajó sobre 20 colmenas tipo Langstroth, de un híbrido de Apis mellifera (Linnaeus infestadas naturalmente por el ácaro Varroa destructor, y seleccionadas al azar. En cada una de ellas se escogió un panal de 2 años (viejo que se colocó en el centro del nido de cría, junto con un panal recientemente labrado por las abejas (nuevo. Luego de que ambos cuadros fueran operculados, se los extrajo y se llevaron al laboratorio para su posterior análisis. Cada una de las celdas de cría se desoperculó e inspeccionó en busca de ácaros, registrándose el número de hembras de ácaros que habían ingresado para su reproducción, se calculó el nivel de infestación como el cociente entre el número de celdas infestadas por ácaros y el número total de celdas inspeccionadas. Los resultados mostraron que los panales viejos presentaron niveles de infestación significativamente superiores a los registrados en panales nuevos (13,52% ± 3,35 y 6,18% ± 2,12 respectivamente; t = 10,62; p = 1,9 E-9; g. l.= 19. El mismo patrón fue observado en el número promedio de ácaros por panal (443,3 ± 70,54 y 217,85 ± 51,76 para panales viejos y nuevos respectivamente; t = 23,87; p = 1,24 E-15; g. l.= 19. Los ácaros presentan una marcada preferencia por los panales viejos. Esta selección estaría guiada por olores propios de las celdas, que actuarían como atrayentes. Además, posiblemente enmascaran su presencia de esta manera y evitan así ser detectados y eliminados por las abejas nodrizas mediante los comportamientos higiénicos.The aim of this work was to

  13. Efecto del nivel de infestación de Varroa destructor sobre la producción de miel de colonias de Apis mellifera en el altiplano semiárido de México

    Directory of Open Access Journals (Sweden)

    Carlos Aurelio Medina-Flores

    2011-01-01

    Full Text Available El propósito del presente trabajo fue determinar sí el ácaro Varroa destructor afecta la producción de miel en colonias de abejas melíferas (Apis mellifera del altiplano semiárido de México. Se utilizaron 32 colonias que variaban en sus niveles de infestación del ácaro y que no habían recibido ningún acaricida durante dos años. Se determinó la producción de miel y el nivel de parasitosis en abejas adultas de estas colonias y los datos se sometieron a un análisis de correlación. Se encontró una correlación negativa y significativa entre el nivel de infestación por Varroa y la producción de miel (r= -0.44, P=0.01. Los valores medios de infestación y producción de miel (±DE fueron 15.21 ± 8.44 % y 36.26 ± 29.24 kg, respectivamente. Los resultados indican que al incrementarse el nivel de varroosis, la producción de miel se reduce de manera significativa. Se recomienda que las colonias de abejas infestadas por Varroa destructor sean sometidas a métodos de control que reduzcan la población del ácaro para contribuir a incrementar la producción de miel.

  14. Frecuencia de Varroa destructor, Nosema apis y Acarapis woodi en colonias manejadas y enjambres silvestres de abejas (Apis mellifera en Mérida, Yucatán, México

    Directory of Open Access Journals (Sweden)

    Jesús Froylán Martínez Puc

    2011-01-01

    Full Text Available Las enfermedades y parasitosis que afectan a las abejas melíferas causan importantes pérdidas económicas a la actividad apícola. Sin embargo, los daños provocados por dichas parasitosis se presentan de manera heterogénea en colonias manejadas y en enjambres silvestres. Con la finalidad de determinar la frecuencia y niveles de infestación de V. destructor, N. apis y A. woodi en abejas melíferas en Yucatán, se colectaron un total de 76 muestras de abejas melíferas, durante junio a septiembre de 2006, siendo 27 de colonias manejadas y 49 de enjambres silvestres. La frecuencia de V. destructor en colonias manejadas fue de 62.9 %, con un nivel de infestación de 1.70 ± 0.26 (ácaros/100 abejas, y en los enjambres silvestres fue de 55.1 %, con un nivel de infestación de 1.96 ± 0.44. No se observaron diferencias en la frecuencia (X2 = 0.44, gl = 1, P =0.51, y niveles de infestación (t=0.14, P=0.89. La frecuencia de N. apis en las colonias manejadas fue de 74.0 %, con una media de infestación de 1´480 x 103 ± 232 x 103 (esporas/ abeja, y en los enjambres silvestres de 53.0 %, con una media de infestación de 1´416 x 103 ± 264 x 103, no se observaron diferencias en la frecuencia (X2 = 3.22, gl = 1, P= 0.07 y niveles de infestación (t=0.18, P=0.86. No se detectó la presencia de A. woodi en las muestras analizadas. Los resultados demuestran un aumento en la frecuencia de N. apis en Yucatán.

  15. Índices de prevalencia del ácaro Varroa destructor (Acari: Varroidae en cuadros de cría nuevos o previamente utilizados por Apis mellifera (Hymenoptera: Apidae

    Directory of Open Access Journals (Sweden)

    Jorge, A. MARCANGELI

    2007-01-01

    Full Text Available El objetivo de esta investigación fue comparar los niveles de infestación de Varroa destructor (Anderson & Trueman en panales de cría nuevos y viejos, en colonias de la abeja criolla (híbrido de Apis mellifera mellifera (Linnaeus y Apis mellifera ligustica Spinola. El trabajo se llevó a cabo en un apiario ubicado en Coronel Vidal, provincia de Buenos Aires, durante la primavera del año 2005. Se trabajó sobre 20 colmenas tipo Langstroth, de un híbrido de Apis mellifera (Linnaeus infestadas naturalmente por el ácaro Varroa destructor, y seleccionadas al azar. En cada una de ellas se escogió un panal de 2 años (viejo que se colocó en el centro del nido de cría, junto con un panal recientemente labrado por las abejas (nuevo. Luego de que ambos cuadros fueran operculados, se los extrajo y se llevaron al laboratorio para su posterior análisis. Cada una de las celdas de cría se desoperculó e inspeccionó en busca de ácaros, registrándose el número de hembras de ácaros que habían ingresado para su reproducción, se calculó el nivel de infestación como el cociente entre el número de celdas infestadas por ácaros y el número total de celdas inspeccionadas. Los resultados mostraron que los panales viejos presentaron niveles de infestación significativamente superiores a los registrados en panales nuevos (13,52% ± 3,35 y 6,18% ± 2,12 respectivamente; t = 10,62; p = 1,9 E-9; g. l.= 19. El mismo patrón fue observado en el número promedio de ácaros por panal (443,3 ± 70,54 y 217,85 ± 51,76 para panales viejos y nuevos respectivamente; t = 23,87; p = 1,24 E-15; g. l.= 19. Los ácaros presentan una marcada preferencia por los panales viejos. Esta selección estaría guiada por olores propios de las celdas, que actuarían como atrayentes. Además, posiblemente enmascaran su presencia de esta manera y evitan así ser detectados y eliminados por las abejas nodrizas mediante los comportamientos higiénicos.

  16. Reproductive ability and level of infestation of the Varroa destructor mite in Apis mellifera apiaries in Blumenau, State of Santa Catarina, Brazil - doi: 10.4025/actascibiolsci.v36i1.20366

    Directory of Open Access Journals (Sweden)

    Francisco Estevão Carneiro

    2013-08-01

    Full Text Available Varroa destructor mite causes mortality of Apis mellifera bees throughout the world. Its greatest damage to these colonies has been reported in European countries and North America. The impact of the mite is related to the climate and the bee race on each region in which the plague has been established. Varroa causes little damage to the colonies of africanized honeybees in Brazil and the levels of infestation are relatively small and stable. The reproductive ability of Varroa females was evaluated in pupae of workers of 17-18 days of age, obtained from eight beehives of africanized bees for twelve months. The average number of offspring (deutonymphs, protonymphs and eggs each Varroa produced was 3.18 ± 0.19. The average total number of deutonymph and protonymph was, respectively, 1.57 ± 0.15 and 1.61 ± 0.14. The levels of infestation demonstrated that the plague continue reaching low levels, the average was 4.11 ± 3.42.

  17. The science and management of sex verification in sport | Tucker ...

    African Journals Online (AJOL)

    The verification of gender eligibility in sporting competition poses a biological and management challenge for sports science and medicine, as well as for sporting authorities. It has been established that in most sporting events, the strength and power advantage possessed by males as a result of the virilising action of ...

  18. DIGITAL FLOOD INSURANCE RATE MAP DATABASE, TUCKER COUNTY, WV, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk...

  19. Flutuação populacional de esporângios de Peronospora destructor no ar e sua relação com a severidade do míldio da cebola

    Directory of Open Access Journals (Sweden)

    Leandro Luiz Marcuzzo

    2015-03-01

    Full Text Available Em experimento de campo nos anos de 2011, 2012 e 2013 quantificou-se a flutuação de esporângios de Peronospora destructor e sua relação com a severidade de míldio em cebola. Mudas de cebola do cultivar Bola Precoce foram transplantadas em quatro repetições de 60 plantas. Os esporângios foram coletados através de um coletor de esporos tipo "cata-vento", contendo uma lâmina de microscópio untada com vaselina, a qual era quantificada semanalmente com auxílio de microscópio. A severidade da doença foi analisada através da porcentagem de área foliar afetada pela doença. O número de esporângios e a severidade do míldio da cebola foram submetidos ao cálculo do coeficiente de correlação linear de Pearson (r. Nos anos de 2011 e 2012 a coleta de esporângios ocorreu posteriormente à constatação da doença, provavelmente devido haver baixo inóculo no ar. Já no ano de 2013 a coleta de esporângios ocorreu anteriormente à ocorrência da doença, porém de forma esporádica e em pequena quantidade, presupondo que esses estavam no ar e foram capturados pelo coletor. A correlação entre as variáveis flutuações de esporângios e a severidade da doença foi significativa, r=0,90, r=0,94 e r=0,80; para os anos de 2011, 2012 e 2013 respectivamente. A severidade da doença em cebola é influenciada pela presença dos esporângios coletadas do ar.

  20. Control del parásito Varroa destructor (Acari: Varroidae en colmenas de la abeja Apis mellifera (Hymenoptera: Apidae mediante la aplicación de la técnica de entrampado

    Directory of Open Access Journals (Sweden)

    Natalia DAMIANI

    2006-01-01

    Full Text Available La parasitosis causada por el ácaro Varroa destructor (Anderson & Trueman es, actualmente considerada el mayor escollo para el desarrollo de la apicultura. El objetivo del presente trabajo fue evaluar la técnica del entrampamiento de ácaros en panales de cría, como posible método de control de la parasitosis. El trabajo se llevó a cabo en Coronel Vidal, provincia de Buenos Aires. Se trabajó sobre colmenas tipo Langstroth del híbrido regional de Apis mellifera (Linneaus. En cada colmena experimental se procedió a confinar a la reina en panales trampa específicos, con el fin de poder controlar la oviposición. Estos panales, luego de ser operculados por las obreras, fueron llevados al laboratorio donde se desoperculó cada una de las celdas de cría, y se contabilizó el número de ácaros presentes. Esta técnica se aplicó variando el número de panales trampa (1-3 colocados, tanto para los constituidos por celdas de cría de obreras como de zánganos. También, se evaluó el impacto de la aplicación de esta técnica sobre el desarrollo de las colonias, mediante la medición de su productividad. Los resultados indican, que la técnica empleada sólo es efectiva, cuando se aplican tres panales de cría de zánganos de manera consecutiva alcanzando una efectividad máxima de 84%. Cuando se aplican tres panales de obreras, la técnica mostró niveles de efectividad muy inferiores (14%. En las colonias sobre las que se aplicó esta técnica, la productividad de miel se redujo significativamente, comparada con las colonias control. Esta técnica resulta ideal para ser combinada con otros mecanismos de control, disminuyendo la aplicación de sustancias químicas que puedan contaminar la miel, y la generación de resistencia por parte del ácaro frente a los principios activos utilizados para su control.

  1. Infestação pelo Ácaro Varroa destructor (Anderson & Trueman (Mesostigmata: Varroidae em Operárias Adultas e em Células de Cria de Abelhas Africanizadas Apis mellifera Linnaeus (Hymenoptera: Apidae na Região de Franca-SP

    Directory of Open Access Journals (Sweden)

    Aline Turcatto

    2012-12-01

    Abstract. The mite Varroa destructor (Anderson & Trueman, has been, until now, one of the pest that causes more damage to the beekeeping worldwide, alone or associated with another bee diseases. Several factors affects the variation of the indexes of infestation and reproduction, such as climate, bee breed, development time, hygienic behavior; being that temperature is a environmental variable that acts on the variation of these indexes: the infestation increases in the colder months and decrease in warmer months, so in the months of autumn and winter occurs the biggest infestation by varroa in the beehives. Were evaluated the indexes of infestation by V. destructor on adult worker and brood cells to ascertain how these indexes rates, in months of autumn, in an africanized bees apiary located in region of Cerrado, surrounded by plantations of sugar cane, with a tropical climate and food in nature. The sample was collected in two years, in the months of May and June 2005 and April and June 2007 in the Experimental Apiary of Franca University-UNIFRAN, located in the municipality of Restiga-SP. The medium indexes of infestation in broods were higher in May/2005 (12.44% than June/2005 (7.78%, were also higher in April/2007 (3% than in June/2007 (0%; all the differences weren’t statistically significant. The medium indexes of infestation in adult workers were lesser in May/2005 (0.95% than June/2005 (1.90% and lesser in April/2007 (0.90% than in June/2007 (4.43%; the difference observed in 2005 was not statistically significant, unlike that observed in 2007 (P=0.031.

  2. Comparación de la eficacia del ácido fórmico y del fluvalinato, como métodos de control de Varroa destructor (Acari: Varroidae en colmenas de Apis mellifera (Hymenoptera: Apidae, en Ñuble, centro sur de Chile

    Directory of Open Access Journals (Sweden)

    Daniel GONZÁLEZ-ACUÑA

    2005-01-01

    Full Text Available Durante la primavera de 2000, se comparó la eficacia del ácido fórmico al 85 % y del fluvalinato como acaricidas contra Varroa destructor Anderson y Trueman en colmenas de Apis mellifera L., ubicadas en el Campus Chillán de la Universidad de Concepción (36o36‘S 72o0,6 ́W. Se formaron tres grupos de diez colmenas. El grupo 1 fue tratado con ácido fórmico al 85% aplicado en Vaporizadores Universales MHT ®; el grupo 2 se utilizó como con- trol, sin recibir ningún tipo de tratamiento; el grupo 3, se trató con tablillas de pino (Pinus radiata impregnadas en fluvalinato al 3 %. Al finalizar la aplicación de los acaricidas en estudio, las colmenas de los tres grupos fueron sometidas a un tratamiento testigo con Bayvarol® (flumetrín. La mayor eficacia se reportó en el grupo tratado con fluvalinato arrojando un promedio de 98,05 ± 2,13 %. De la misma manera con ácido fórmico se obtuvo una eficacia promedio de 88,26 ± 9,12 %, mientras que en el grupo control la mortalidad natural en promedio fue de 41,11 ± 11,52 %.

  3. On low-rank updates to the singular value and Tucker decompositions

    Energy Technology Data Exchange (ETDEWEB)

    O' Hara, M J

    2009-10-06

    The singular value decomposition is widely used in signal processing and data mining. Since the data often arrives in a stream, the problem of updating matrix decompositions under low-rank modification has been widely studied. Brand developed a technique in 2006 that has many advantages. However, the technique does not directly approximate the updated matrix, but rather its previous low-rank approximation added to the new update, which needs justification. Further, the technique is still too slow for large information processing problems. We show that the technique minimizes the change in error per update, so if the error is small initially it remains small. We show that an updating algorithm for large sparse matrices should be sub-linear in the matrix dimension in order to be practical for large problems, and demonstrate a simple modification to the original technique that meets the requirements.

  4. When are Overcomplete Topic Models Identifiable? Uniqueness of Tensor Tucker Decompositions with Structured Sparsity

    Science.gov (United States)

    2013-08-14

    Communications and Computing, Electrical Engineering and Computer Science Dept., University of California, Irvine, USA 92697. Email : a.anandkumar...uci.edu,mjanzami@uci.edu. Daniel Hsu and Sham Kakade are with Microsoft Research New England, 1 Memorial Drive, Cambridge, MA 02142. Email : dahsu...Andreas Maurer, Massimiliano Pontil, and Bernardino Romera-Paredes. Sparse coding for multitask and transfer learning. ArxXiv preprint, abs/1209.0738, 2012

  5. Kuhn-Tucker optimization based reliability analysis for probabilistic finite elements

    Science.gov (United States)

    Liu, W. K.; Besterfield, G.; Lawrence, M.; Belytschko, T.

    1988-01-01

    The fusion of probability finite element method (PFEM) and reliability analysis for fracture mechanics is considered. Reliability analysis with specific application to fracture mechanics is presented, and computational procedures are discussed. Explicit expressions for the optimization procedure with regard to fracture mechanics are given. The results show the PFEM is a very powerful tool in determining the second-moment statistics. The method can determine the probability of failure or fracture subject to randomness in load, material properties and crack length, orientation, and location.

  6. 76 FR 12365 - Canaan Valley National Wildlife Refuge, Tucker and Grant Counties, WV; Final Comprehensive...

    Science.gov (United States)

    2011-03-07

    .... Alternative B, the ``Service-Preferred Alternative,'' is designed to balance the conservation of a mixed... obtain copies of the final CCP and FONSI by any of the following methods. You may request a hard copy or... species, encouraging research that benefits our resource decisions, continuing to acquire land from...

  7. Combating Varroa destructor in Honeybee Colonies Using Flumethrin or Fluvalinate

    Directory of Open Access Journals (Sweden)

    A. Gregorc

    2007-01-01

    Full Text Available Mite mortality in two apiaries, one with 32 and the other with 15 honeybee (Apis mellifera carnica colonies, was recorded prior to and after flumethrin or fluvalinate treatments and after a control, oxalic-acid application. During the 42- and 51-day pre-treatment periods, the average daily natural mite drop was 0.04 (± 0.04 and 2.82 (± 2.19, respectively, which represents 1.09% (± 1.06 and 3.84% (± 3.04 of the total number of mites found during the experiment. The flumethrin or fluvalinate applications resulted in an average mite mortality at the two apiaries of 214.46 (± 260.02 and 4,098.64 (± 2,508.31. The treatments resulted in a 19.11% (± 14.62 and a 39.28% (± 10.47 reduction in the number of mites in slightly infested colonies and 94.30% (± 4.26 and 96.24% (± 3.14 in highly infested colonies. The difference in treatment efficacy between both apiaries was significant (P < 0.001 and indicates that fluvalinate and flumethrin are highly efficacious in dealing with highly infested honeybee colonies with sealed brood. The importance of effective mite control in colonies with a high level of natural mite mortality is discussed in this study.

  8. Genetic diversity of Mayetiola destructor and Mayetiola hordei ...

    African Journals Online (AJOL)

    Owner

    simple sequence repeats (ISSRs). Maha MEZGHANI KHEMAKHEM1, Mohamed MARRAKCHI1 and Hanem MAKNI1,2*. 1Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie, Faculté des Sciences de Tunis, 2092 El. Manar, Tunisie. 2Institut Supérieur de l'Animation pour la Jeunesse et la Culture de Bir ...

  9. Assessing grooming behavior of Russian honey bees toward Varroa destructor.

    Science.gov (United States)

    The grooming behavior of Russian bees was compared to Italian bees. Overall, Russian bees had significantly lower numbers of mites than the Italian bees with a mean of 1,937 ± 366 and 5,088 ± 733 mites, respectively. This low mite population in the Russian colonies was probably due to the increased ...

  10. An Archaeological an Bioarchaeological Perspective. The Tucker (41DT104) and Sinclair (41DT105) Cemeteries of Delta County, Texas

    Science.gov (United States)

    1988-01-01

    presence of abscesses and calculus deposits, agenesis, and the extent of antemortem tooth loss. The teeth were examined for caries using a new dental...childnood. Conversely. the absence of any chronic skeletal pathology, other than age-related degenerative arthritis, indicates this individual enjoyed good...and left acetabulum (rim and lunate surfaces), the apices of the sacroiliac auricular surfaces, a fragment of thv inferior demiface of the right

  11. Swarm prevention and spring treatment against Varroa destructor in honey bee colonies (Apis mellifera)

    NARCIS (Netherlands)

    Cornelissen, B.; Gerritsen, L.J.M.

    2006-01-01

    In 2004 and 2005 experiments were carried out to test the efficacy and efficiency of Varroa control combined with swarm prevention methods in spring. Honey bee colonies were split in an artificial swarm and a brood carrier. Hereafter the swarms were treated with oxalic acid and the brood carriers

  12. Data from: Interaction between Varroa destructor and imidacloprid reduces flight capacity of honeybees

    NARCIS (Netherlands)

    Blanken, Lisa; Langevelde, van F.; Dooremalen, van J.A.

    2015-01-01

    Current high losses of honey bees seriously threaten crop pollination. Whereas parasite exposure is acknowledged as an important cause of these losses, the role of insecticides is controversial. Parasites and neonicotinoid insecticides reduce homing success of foragers, e.g., by reduced orientation,

  13. Genetic characterization of Russian honey bee stock selected for improved resistance to Varroa destructor.

    Science.gov (United States)

    Bourgeois, A Lelania; Rinderer, Thomas E

    2009-06-01

    Maintenance of genetic diversity among breeding lines is important in selective breeding and stock management. The Russian Honey Bee Breeding Program has strived to maintain high levels of heterozygosity among its breeding lines since its inception in 1997. After numerous rounds of selection for resistance to tracheal and varroa mites and improved honey production, 18 lines were selected as the core of the program. These lines were grouped into three breeding blocks that were crossbred to improve overall heterozygosity levels of the population. Microsatellite DNA data demonstrated that the program has been successful. Heterozygosity and allelic richness values are high and there are no indications of inbreeding among the three blocks. There were significant levels of genetic structure measured among the three blocks. Block C was genetically distinct from both blocks A and B (F(ST) = 0.0238), whereas blocks A and B did not differ from each other (F(ST) = 0.0074). The same pattern was seen for genic (based on numbers of alleles) differentiation. Genetic distance, as measured by chord distance, indicates that all of the 18 lines are equally distant, with minimal clustering. The data indicate that the overall design of the breeding program has been successful in maintaining high levels of diversity and avoiding problems associated with inbreeding.

  14. Interaction between Varroa destructor and imidacloprid reduces flight capacity of honeybees

    NARCIS (Netherlands)

    Blanken, Lisa; Langevelde, van F.; Dooremalen, van J.A.

    2015-01-01

    Current high losses of honeybees seriously threaten crop pollination. Whereas parasite exposure is acknowledged as an important cause of these losses, the role of insecticides is controversial. Parasites and neonicotinoid insecticides reduce homing success of foragers (e.g. by reduced orientation),

  15. The evaluation of the efficacy of sodium carbonate as zearalenone destructor in feeding stuffs.

    Science.gov (United States)

    Polak, M; Gajecki, M; Kulik, T; Łuczyński, M K; Obremski, K; Góra, M; Gajecka, M; Jakimiuk, E; Zielonka, Ł

    2009-01-01

    Contamination of feed with zearalenone (ZEA) is still a serious problem in farm animals feeding, especially in gilts, sensitive to this compound. The relative failure of current methods of decontamination and quality control lead us to look for new techniques. The commonly accepted method for breaking down ZEA was performed in controlled temperature and time conditions. Various sodium carbonate doses (0.5 - 4%) were added to feed naturally contaminated with ZEA (ZEA biosynthesis by F. graminearum isolates). These doses were found to be effective in in vitro studies. The addition of 2% sodium carbonate gave the best results in reducing the phytoestrogen in the feed.

  16. Influence of Varroa mite (Varroa destructor) infestation levels and management practices on insecticide sensitivity in the honey bee (Apis mellifera)

    Science.gov (United States)

    Because Varroa mites may cause devastating losses of honey bees through direct feeding, transmitting diseases, and increasing pathogen susceptibility, chemical and mechanical practices commonly are used to reduce mite infestation. While miticide applications are typically the most consistent and eff...

  17. A massive expansion of effector genes underlies gall-formation in the wheat pest Mayetiola destructor

    DEFF Research Database (Denmark)

    Zhao, Chaoyang; Escalante, Lucio Navarro; Chen, Hang

    2015-01-01

    Gall-forming arthropods are highly specialized herbivores that, in combination with their hosts, produce extended phenotypes with unique morphologies [1]. Many are economically important, and others have improved our understanding of ecology and adaptive radiation [2]. However, the mechanisms...... in plants and E3-ligase-mimicking effectors in plant pathogenic bacteria. SSGP-71 proteins and wheat Skp proteins interact in vivo. Mutations in different SSGP-71 genes avoid the effector-triggered immunity that is directed by the wheat resistance genes H6 and H9. Results point to effectors as the agents...

  18. Effect of oxalic acid on the mite Varroa destructor and its host the honey bee Apis mellifera

    Czech Academy of Sciences Publication Activity Database

    Papežíková, I.; Palíková, M.; Kremserová, Silvie; Zachová, A.; Peterová, H.; Babák, V.; Navrátil, S.

    2017-01-01

    Roč. 56, č. 4 (2017), s. 400-408 ISSN 0021-8839 Institutional support: RVO:68081707 Keywords : programmed cell-death * temperate climate * colony losses Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Genetics and heredity (medical genetics to be 3) Impact factor: 1.364, year: 2016

  19. Sequence recombination and conservation of Varroa destructor virus-1 and deformed wing virus in field collected honey bees (Apis mellifera.

    Directory of Open Access Journals (Sweden)

    Hui Wang

    Full Text Available We sequenced small (s RNAs from field collected honeybees (Apis mellifera and bumblebees (Bombuspascuorum using the Illumina technology. The sRNA reads were assembled and resulting contigs were used to search for virus homologues in GenBank. Matches with Varroadestructor virus-1 (VDV1 and Deformed wing virus (DWV genomic sequences were obtained for A. mellifera but not B. pascuorum. Further analyses suggested that the prevalent virus population was composed of VDV-1 and a chimera of 5'-DWV-VDV1-DWV-3'. The recombination junctions in the chimera genomes were confirmed by using RT-PCR, cDNA cloning and Sanger sequencing. We then focused on conserved short fragments (CSF, size > 25 nt in the virus genomes by using GenBank sequences and the deep sequencing data obtained in this study. The majority of CSF sites confirmed conservation at both between-species (GenBank sequences and within-population (dataset of this study levels. However, conserved nucleotide positions in the GenBank sequences might be variable at the within-population level. High mutation rates (Pi>10% were observed at a number of sites using the deep sequencing data, suggesting that sequence conservation might not always be maintained at the population level. Virus-host interactions and strategies for developing RNAi treatments against VDV1/DWV infections are discussed.

  20. The effects of Imidacloprid and Varroa destructor on the survival and health of European honey bees, Apis mellifera

    Science.gov (United States)

    In the past decade, there has been growing concern over the decline in populations of honeybees and other pollinators which are vital part of our food security. It is therefore imperative to identify factors that are responsible for accelerated decline in bee population and develop solutions toward ...

  1. Varying congruence of hygienic responses to Varroa destructor and freeze-killed brood among different types of honey bees

    Science.gov (United States)

    Different types of honey bees, Apis mellifera L., have been selectively bred for enhanced hygiene (i.e., removal of affected brood from sealed cells) to improve resistance to diseases and parasites. Bees selected for removal of freeze-killed brood (FKB) have protection from several microbial disease...

  2. An Observational Study of Honey Bee Colony Winter Losses and Their Association with Varroa destructor, Neonicotinoids and Other Risk Factors

    NARCIS (Netherlands)

    Zee, van der R.; Gray, A.; Rijk, de T.C.

    2015-01-01

    This article presents results of an analysis of honey bee losses over the winter of 2011-2012 in the Netherlands, from a sample of 86 colonies, located at 43 apiaries. The apiaries were selected using spatially stratified random sampling. Colony winter loss data were collected and related to various

  3. Influence of Varroa Mite (Varroa destructor Management Practices on Insecticide Sensitivity in the Honey Bee (Apis mellifera

    Directory of Open Access Journals (Sweden)

    Frank D. Rinkevich

    2017-01-01

    Full Text Available Since Varroa mites may cause devastating losses of honey bees through direct feeding, transmitting diseases, and increasing pathogen susceptibility, chemical and mechanical practices commonly are used to reduce mite infestation. While miticide applications are typically the most consistent and efficacious Varroa mite management method, miticide-induced insecticide synergism in honey bees, and the evolution of resistance in Varroa mites are reasonable concerns. We treated colonies with the miticide amitraz (Apivar®, used IPM practices, or left some colonies untreated, and then measured the effect of different levels of mite infestations on the sensitivity of bees to phenothrin, amitraz, and clothianidin. Sensitivity to all insecticides varied throughout the year among and within treatment groups. Clothianidin sensitivity decreased with increasing mite levels, but no such correlation was seen with phenothrin or amitraz. These results show that insecticide sensitivity is dynamic throughout the 5 months test. In-hive amitraz treatment according to the labeled use did not synergize sensitivity to the pesticides tested and this should alleviate concern over potential synergistic effects. Since IPM practices were largely ineffective at reducing Varroa mite infestation, reliance on chemical methods of Varroa mite management is likely to continue. However, miticides must be used judiciously so the long term effectiveness of these compounds can be maximized. These data demonstrate the complex and dynamic variables that contribute to honey bee colony health. The results underscore the importance of controlling for as many of these variables as possible in order to accurately determine the effects of each of these factors as they act alone or in concert with others.

  4. Female Sex Tourism in the Caribbean – A “Fair Trade” or a New Kind of Colonial Exploitation? – Tanika Gupta’s Sugar Mummies and Debbie Tucker Green’s Trade

    Directory of Open Access Journals (Sweden)

    Klein Hildegard

    2015-12-01

    Full Text Available The above-mentioned authors offer a challenging and revealing study of the enjoyments and drawbacks of female sex tourism. I examine the interactions between white female tourists and local black men from the context of post-colonialism, asking whether these encounters can be considered a “fair trade” or whether they are the neo-colonising of people in this ex-slave society.

  5. Brood removal or queen caging combined with oxalic acid treatment to control varroa mites (Varroa destructor) in honey bee colonies (Apis mellifera)

    Science.gov (United States)

    Few studies of honey bee colonies exist where varroa mite control is achieved by integrating broodless conditions, through either total brood removal or queen caging, in combination with oxalic acid (OA) applications. We observed significant varroa mortality after applications of OA in obtaining bro...

  6. Factors influencing the prevalence and infestation levels of Varroa destructor in honeybee colonies in two highland agro-ecological zones of Uganda.

    Science.gov (United States)

    Chemurot, Moses; Akol, Anne M; Masembe, Charles; de Smet, Lina; Descamps, Tine; de Graaf, Dirk C

    2016-04-01

    Varroa mites are ecto-parasites of honeybees and are a threat to the beekeeping industry. We identified the haplotype of Varroa mites and evaluated potential factors that influence their prevalence and infestation levels in the eastern and western highland agro-ecological zones of Uganda. This was done by collecting samples of adult worker bees between December 2014 and September 2015 in two sampling moments. Samples of bees were screened for Varroa using the ethanol wash method and the mites were identified by molecular techniques. All DNA sequences obtained from sampled mite populations in the two zones were 100 % identical to the Korean Haplotype (AF106899). Mean mite prevalence in the apiaries was 40 and 53 % for the western and eastern zones, respectively, during the first sampling. Over the second sampling, mean mite prevalence increased considerably in the western (59 %) but not in the eastern (51 %) zone. Factors that were associated with Varroa mite infestation levels include altitude, nature of apiary slope and apiary management practices during the first sampling. Our results further showed that Varroa mites were spreading from lower to higher elevations. Feral colonies were also infested with Varroa mites at infestation levels not significantly different from those in managed colonies. Colony productivity and strength were not correlated to mite infestation levels. We recommend a long-term Varroa mite monitoring strategy in areas of varying landscape and land use factors for a clear understanding of possible changes in mite infestation levels among African honeybees for informed decision making.

  7. In-depth proteomic analysis of Varroa destructor: Detection of DWV-complex, ABPV, VdMLV and honeybee proteins in the mite

    Czech Academy of Sciences Publication Activity Database

    Erban, T.; Harant, K.; Hubálek, Martin; Vítámvás, P.; Kamler, M.; Poltronieri, P.; Tyl, J.; Markovič, M.; Titěra, D.

    2015-01-01

    Roč. 5, Sep 11 (2015), 13907/1-13907/16 ISSN 2045-2322 Institutional support: RVO:61388963 Keywords : deformed wing virus * Apis mellifera L. * bee paralysis virus Subject RIV: CE - Biochemistry Impact factor: 5.228, year: 2015 http://www.nature.com/articles/srep13907

  8. Development of improved molecular methods for the detection of deformed wing virus (DWV) in honeybees (Apis mellifera L.) and mites ( Varroa destructor Oud.).

    Science.gov (United States)

    Parrella, G; Caprio, E; Mazzone, P

    2006-01-01

    A simple and rapid method for the extraction of total nucleic acid from honeybee and mite, useful either as template for RT-PCR or in nucleic acids hybridization, was developed. Sensitivity of the methods were evaluated up to 10(9) and 10(6) dilution of TNAs extracted from a single honeybee, for reverse transcriptase polymerase chain reaction and molecular hybridization respectively. The two diagnostic methods developed could be useful for the study of the molecular biology and the pathology of DWV. For practical applications dot-blot hybridization could be used in order to study the incidence of DWV in honeybees populations. The method is enough sensitive, rapid and less affected by contamination problems compared to RT-PCR and thus it could be applied to the sanitary certification of honeybees and their products.

  9. Are dispersal mechanisms changing the host-parasite relationship and increasing the virulence of Varroa destructor [Acari:Varroidae] in managed honey bee [Hymenoptera: Apidae] colonies?

    Science.gov (United States)

    Varroa mites are the most serious pest of honey bees worldwide, and difficult to control in managed colonies. We show in a longitudinal study that even with multiple miticide treatments in the summer and fall, mite numbers remained high and colony losses exceeded 55%. Furthermore, large heavily infe...

  10. Development of a user-friendly delivery method for the fungus Metarhizium anisopliae to control the ectoparasitic mite Varroa destructor in honey bee, Apis mellifera, colonies.

    Science.gov (United States)

    Kanga, Lambert H B; Adamczyk, John; Patt, Joseph; Gracia, Carlos; Cascino, John

    2010-12-01

    A user-friendly method to deliver Metarhizium spores to honey bee colonies for control of Varroa mites was developed and tested. Patty blend formulations protected the fungal spores at brood nest temperatures and served as an improved delivery system of the fungus to bee hives. Field trials conducted in 2006 in Texas using freshly harvested spores indicated that patty blend formulations of 10 g of conidia per hive (applied twice) significantly reduced the numbers of mites per adult bee, mites in sealed brood cells, and residual mites at the end of the 47-day experimental period. Colony development in terms of adult bee populations and brood production also improved. Field trials conducted in 2007 in Florida using less virulent spores produced mixed results. Patty blends of 10 g of conidia per hive (applied twice) were less successful in significantly reducing the number of mites per adult bee. However, hive survivorship and colony strength were improved, and the numbers of residual mites were significantly reduced at the end of the 42-day experimental period. The overall results from 2003 to 2008 field trials indicated that it was critical to have fungal spores with good germination, pathogenicity and virulence. We determined that fungal spores (1 × 10(10) viable spores per gram) with 98% germination and high pathogenicity (95% mite mortality at day 7) provided successful control of mite populations in established honey bee colonies at 10 g of conidia per hive (applied twice). Overall, microbial control of Varroa mite with M. anisopliae is feasible and could be a useful component of an integrated pest management program.

  11. Population growth of Varroa destructor (Acari: Varroidae) in colonies of Russian and unselected honey bee (Hymenoptera: Apidae) stock as related to numbers of foragers with mites

    Science.gov (United States)

    Varroa mites are an external parasite of honey bees and a leading cause of colony losses worldwide. Varroa populations can be controlled with miticides, but mite resistant stocks such as the Russian honey bee (RHB) also are available. RHB and other mite resistant stock limit Varroa population growth...

  12. Winter honey bee colony losses, Varroa destructor control strategies, and the role of weather conditions: Results from a survey among beekeepers.

    Science.gov (United States)

    Beyer, Marco; Junk, Jürgen; Eickermann, Michael; Clermont, Antoine; Kraus, François; Georges, Carlo; Reichart, Andreas; Hoffmann, Lucien

    2018-06-01

    Sets of treatments that were applied against varroa mites in the Luxembourgish beekeeper community were surveyed annually with a questionnaire between the winters 2010/11 and 2014/15. The average temperature and the precipitation sum of the month, when the respective varroa control method was applied were considered as co-variables when evaluating the efficacy of varroa control regimes. Success or failure of control regimes was evaluated based on the percentage of colonies lost per apiary in the winter following the treatment(s). Neither a positive nor a negative effect of formic acid (concentration 60%, w/v) on the colony losses could be found, irrespective of the weather conditions around the time of application. The higher concentration of 85% formic acid was linked with reduced colony losses when applications were done in August. Colony losses were reduced when Thymovar was applied in July or August, but applications in September were associated with increased losses compared with apiaries not treated with Thymovar during the same period. Apilife application in July as well as Apivar applications between July and September were associated with reduced colony losses. The removal of the drone brood and trickled oxalic acid application had beneficial effects when being done in April and December, respectively. Relatively warm (3.0±1.3°C) and wet (507.0±38.6mm/2months) conditions during the winter months December and January and relatively cool (17.2±1.4°C average monthly temperature) and wet (110.8±55.5mm/month) conditions in July were associated with elevated honey bee colony losses. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. 78 FR 25479 - Notice of Determinations Regarding Eligibility To Apply for Worker Adjustment Assistance

    Science.gov (United States)

    2013-05-01

    ... Impact date 82,292 Umicore Thin Film Products, Providence, RI. Division of Umicore USA, Inc... Advertising & Tucker, GA. Publishing LLC, Tucker, Georgia Division, YP Subsidiary Holdings LLC, YP Holdings...

  14. Assessing the effects of human-induced land degradation in the former homelands of northern South Africa with a 1 km AVHRR NDVI time-series

    CSIR Research Space (South Africa)

    Wessels, Konrad J

    2004-05-15

    Full Text Available been successfully estimated with the normalized dif- ference vegetation index (NDVI) derived from satellite data (Deering et al., 1975; Jury et al., 1997; Myneni et al., 1997; Prince, 1991b; Prince & Tucker, 1986; Tucker & Sellers, 1986). NDVI captures... productivity (NPP; Schloss et al., 1999). In arid and semiarid lands, seasonal sums of multitemporal NDVI are strongly corre- lated with vegetation production (Prince, 1991b; Prince & Tucker, 1986; Nicholson & Farrar, 1994; Nicholson et al., 1998). Human...

  15. Wheat Mds-1 encodes a heat-shock protein and governs susceptibility towards the Hessian fly gall midge

    Science.gov (United States)

    Plant pests including insects must manipulate plants in order to utilize the nutrition and environment of the host. Here, we show that the heat-shock protein gene Mayetiola destructor susceptibility gene-1 (Mds-1) is a major susceptibility gene in wheat that allows the gall midge M. destructor, com...

  16. 75 FR 5698 - Approval and Promulgation of Implementation Plans; Albuquerque-Bernalillo County, NM; Excess...

    Science.gov (United States)

    2010-02-04

    ... adverse comments by March 8, 2010. If adverse comments are received, EPA will publish a timely withdrawal... also included proposed revisions to NMAC 20.11.69--Pathological Waste Destructors. NMAC 20.11.69-- Pathological Waste Destructors is not currently in the EPA-approved SIP for Albuquerque-Bernalillo County. We...

  17. Automatic Relevance Determination for multi-way models

    DEFF Research Database (Denmark)

    Mørup, Morten; Hansen, Lars Kai

    2009-01-01

    of components of data within the Tucker and CP structure. For the Tucker and CP model the approach performs better than heuristics such as the Bayesian Information Criterion, Akaikes Information Criterion, DIFFIT and the numerical convex hull (NumConvHull) while operating only at the cost of estimating...... is available for download at www.erpwavelab.org....

  18. Migration effects on population dynamics of the honeybee-mite interactions

    Science.gov (United States)

    Honeybees are amazing and highly beneficial insect species that play important roles in undisturbed and agricultural ecosystems. Unfortunately, honeybees are increasingly threatened by numerous factors, most notably the parasitic Varroa mite (Varroa destructor Anderson and Trueman). A recent field s...

  19. Leven met de varroamijt in de 21ste eeuw

    NARCIS (Netherlands)

    Blacquiere, T.; Cornelissen, B.; Smeekens, C.C.; Steen, van der J.J.M.

    2002-01-01

    Overzicht van voorhanden bestrijdingsmethoden tegen Varroa destructor op de korte termijn en vooruitzichten voor de bestrijding op langere termijn. In de nabije toekomst gaat het om bestrijding met diergeneesmiddelen van natuurlijke oorsprong (mierenzuur, oxaalzuur, thymol) in het kader van een

  20. Exploring the host parasitism of the migratory plant-parasitic nematode Ditylenchus destuctor by expressed sequence tags analysis.

    Directory of Open Access Journals (Sweden)

    Huan Peng

    Full Text Available The potato rot nematode, Ditylenchus destructor, is a very destructive nematode pest on many agriculturally important crops worldwide, but the molecular characterization of its parasitism of plant has been limited. The effectors involved in nematode parasitism of plant for several sedentary endo-parasitic nematodes such as Heterodera glycines, Globodera rostochiensis and Meloidogyne incognita have been identified and extensively studied over the past two decades. Ditylenchus destructor, as a migratory plant parasitic nematode, has different feeding behavior, life cycle and host response. Comparing the transcriptome and parasitome among different types of plant-parasitic nematodes is the way to understand more fully the parasitic mechanism of plant nematodes. We undertook the approach of sequencing expressed sequence tags (ESTs derived from a mixed stage cDNA library of D. destructor. This is the first study of D. destructor ESTs. A total of 9800 ESTs were grouped into 5008 clusters including 3606 singletons and 1402 multi-member contigs, representing a catalog of D. destructor genes. Implementing a bioinformatics' workflow, we found 1391 clusters have no match in the available gene database; 31 clusters only have similarities to genes identified from D. africanus, the most closely related species to D. destructor; 1991 clusters were annotated using Gene Ontology (GO; 1550 clusters were assigned enzyme commission (EC numbers; and 1211 clusters were mapped to 181 KEGG biochemical pathways. 22 ESTs had similarities to reported nematode effectors. Interestedly, most of the effectors identified in this study are involved in host cell wall degradation or modification, such as 1,4-beta-glucanse, 1,3-beta-glucanse, pectate lyase, chitinases and expansin, or host defense suppression such as calreticulin, annexin and venom allergen-like protein. This result implies that the migratory plant-parasitic nematode D. destructor secrets similar effectors to

  1. 78 FR 25305 - Notice of Determinations Regarding Eligibility To Apply for Worker Adjustment Assistance

    Science.gov (United States)

    2013-04-30

    ..., Onin Staffing, etc. 82,617 YP Southeast Advertising & Tucker, GA March 27, 2012. Publishing LLC, YP... Enterprise Services, Policy Processing Service, Kelly Services I hereby certify that the aforementioned...

  2. Quinto Tiberio Angelerio and New Measures for Controlling Plague in 16th-Centruy Alghero, Sardinia

    Centers for Disease Control (CDC) Podcasts

    Reginald Tucker reads an abridged version of the Emerging Infectious Diseases’ historical Review, Quinto Tiberio Angelerio and New Measures for Controlling Plague in 16th -Centruy Alghero, Sardinia.

  3. REFractions: The Representing Equivalent Fractions Game

    Science.gov (United States)

    Tucker, Stephen I.

    2014-01-01

    Stephen Tucker presents a fractions game that addresses a range of fraction concepts including equivalence and computation. The REFractions game also improves students' fluency with representing, comparing and adding fractions.

  4. AFSC/RACE/EcoFOCI - Physical oceanographic data collected in support of EcoFOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the Gulf of Alaska - 1995 to Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pressure, temperature and salinity data. Data are available in 1 meter intervals in conjunction with the MARMAP 20/60 bongo array, CalVET, and Tucker trawl. Maximum...

  5. GLOBEC NEP MOCNESS Plankton (MOC1) Data, 2000-2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GLOBEC (GLOBal Ocean ECosystems Dynamics) NEP (Northeast Pacific) California Current Program MOCNESS Plankton (MOC1) Data The MOCNESS is based on the Tucker Trawl...

  6. Measurements and Counts for Larval and Juvenile Beryx Specimens

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Larval alfonsin (Beryx species) were collected in the vicinity of the Southeast Hancock Seamount. A three-net Tucker trawl (I m2 effective mouth opening and 0.333 mm...

  7. Doppler ultrasonography of the pectinis oculi artery in harpy eagles ...

    African Journals Online (AJOL)

    Ibrahim Eldaghayes

    2017-03-21

    Güntürkün, 2000; Jones et al.,. 2007), accommodation by corneal and lenticular measures (Samuelson, 2007), bifoveate retinae. (Tucker, 2000), and an anangiotic (avascular) retina. (Ruggeri et al., 2010). As with all avian ...

  8. HISTORIANS AND MIRACLES : THE PRINCIPLE OF ANALOGY ...

    African Journals Online (AJOL)

    2008-11-27

    Nov 27, 2008 ... reworked versions of sections of the PhD ..... provides wider scope and is more fruitful than literal interpretations (Tucker 2005:385, 388), ..... Witherington writes: Even some contemporary Bible scholars assume that miracles.

  9. 78 FR 54487 - Notice of Determinations Regarding Eligibility To Apply for Worker Adjustment Assistance

    Science.gov (United States)

    2013-09-04

    ... Services, Basking Ridge, NJ.... Strategy and Operations. 82,882 Southern New England Telephone New Haven... Paso, TX Americanos, Greyhound Lines. 82,890 YP Southeast Advertising & Tucker, GA Publishing LLC...

  10. CrossTalk: The Journal of Defense Software Engineering. Volume 20, Number 11, November 2007

    National Research Council Canada - National Science Library

    2007-01-01

    ...: Partnership for Project Success." Jennifer Tucker and Hile Rutledge describe the necessity of maximizing team performance in "Shaping Motivation and Emotion in Technology Teams," and Kasey Thompson and Tim Border teach managers...

  11. Multilinear operators for higher-order decompositions.

    Energy Technology Data Exchange (ETDEWEB)

    Kolda, Tamara Gibson

    2006-04-01

    We propose two new multilinear operators for expressing the matrix compositions that are needed in the Tucker and PARAFAC (CANDECOMP) decompositions. The first operator, which we call the Tucker operator, is shorthand for performing an n-mode matrix multiplication for every mode of a given tensor and can be employed to concisely express the Tucker decomposition. The second operator, which we call the Kruskal operator, is shorthand for the sum of the outer-products of the columns of N matrices and allows a divorce from a matricized representation and a very concise expression of the PARAFAC decomposition. We explore the properties of the Tucker and Kruskal operators independently of the related decompositions. Additionally, we provide a review of the matrix and tensor operations that are frequently used in the context of tensor decompositions.

  12. Some aspects of thermoregulation in three species of southern ...

    African Journals Online (AJOL)

    transmitter. Its pulse rate is determined by a temperature .... tion of tortoises at intervals of 15 min has little effect on the overall .... toises describes the effect of mass on cooling rates .... (Bartholomew & Tucker 1963); altered evaporation rates,.

  13. Current Writing: Text and Reception in Southern Africa - Vol 18, No 1 ...

    African Journals Online (AJOL)

    Lions, leopards and liminal spaces:Representations of Biosociality in the Writings of Katy Payne, Linda Tucker and Gillian van Houten · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. W Woodward ...

  14. Heating and cooling rates and their etTects upon heart rate in the ...

    African Journals Online (AJOL)

    1988-03-16

    Mar 16, 1988 ... is not a direct measure of blood flow to the periphery. (Bartholomew & Tucker ..... retreats to shady areas and assumes a posture similar to that adopted during basking. .... Influence of water vapor pressure on the apparent ...

  15. The Need to Increase Marine Corps Special Operations Command

    Science.gov (United States)

    2009-01-01

    Operations University presentation by Major Mark Raney for USSOCOM elective (lecture, MCU, Quantico VA, 17 Feb 20Q9). 5 Stew Magnuson, "Marine Special...2008 Posture Statement.doc (Accessed 23 December, 2008) 20 David Tucker and Christopher J. Lamb , United States Special Operations Forces (New York...invasion of Afghanistan encroached on the Marine Corps historical role of being "soldiers from the sea." 38 David Tucker and Christopher J. lamb , 182

  16. Le droit comme outil de maintien en emploi : rôle protecteur, rôle destructeur ? Law as an employment maintenance mechanism: protective role, destructive role? El derecho como una herramienta para conservar el empleo: rol protector, rol destructor?

    Directory of Open Access Journals (Sweden)

    Katherine Lippel

    2010-02-01

    Full Text Available Cet article explore les pratiques juridiques et de gestion appliquées au Québec à l’égard des personnes atteintes d’incapacité de travail en raison d’une lésion professionnelle. Il débute par un examen des facteurs associés au succès du retour au travail rapportés dans la littérature des sciences de réadaptation, notamment les études sur la réinsertion précoce. Ensuite, il examine le droit régissant la réadaptation professionnelle, ainsi que son application par les employeurs et la Commission de la santé et de la sécurité du travail (CSST à la lumière des principales conclusions de la littérature en ce qui concerne les facteurs qui facilitent le retour au travail et ceux qui y font obstacle. On conclut que le droit lui-même crée peu d’obstacles à la mise en œuvre d’un retour au travail réussi ; par contre, les pratiques de gestion et de traitement des litiges entourant la mise en œuvre de ce droit peuvent compromettre le succès du retour au travail des personnes ayant subi une lésion professionnelle.This article examines Québec legal and management practices regarding workers disabled due to a work-related injury. The article begins by reviewing key issues raised in the rehabilitation literature with regard to factors that favour a successful return to work after injury, including studies on early return to work. It then examines Québec workers’ rehabilitation legislation and its application by employers and the workers’ compensation board (CSST in light of the key findings from the literature regarding facilitators and obstacles to a successful return to work. It concludes that while the legislation itself creates few obstacles for a successful return to work, current practices in the management and handling of cases involving the implementation of this law may diminish the chances of successful return to work for injured workers.Este artículo explora las prácticas jurídicas y de gestión aplicadas en Quebec, prácticas relacionadas a personas afectadas por una incapacidad para trabajar a consecuencia de una lesión profesional. El artículo se inicia con una evaluación de los factores asociados a una reincorporación exitosa, factores descritos dentro de la literatura en ciencias de la rehabilitación, especialmente en los estudios sobre la reincorporación temprana. A continuación, él examina el derecho que rige la readaptación profesional, así como su aplicación por los empleadores del Quebec y por la Comisión para la Salud y la Seguridad en el Trabajo del Quebec (CSST, a la luz de las principales conclusiones de la literatura en lo que concierne a los factores que facilitan el retorno al trabajo y aquellos que lo obstaculizan. Como conclusión se encuentra que el derecho por sí mismo crea pocos obstáculos para la puesta en marcha de una reincorporación exitosa al trabajo ; sin embargo, las practicas de gestión y el tratamiento de los litigios y litigantes que rodean esta puesta en marcha pueden comprometer el éxito del retorno al trabajo de las personas que han sufrido una lesión profesional.

  17. Aeroallergens in dairy barns near Cooperstown, New York and Rochester, Minnesota

    International Nuclear Information System (INIS)

    Campbell, A.R.; Swanson, M.C.; Fernandez-Caldas, E.; Reed, C.E.; May, J.J.; Pratt, D.S.

    1989-01-01

    We sampled atmospheric barn air using a volumetric air sampler in ten barns near Cooperstown, NY and six barns near Rochester, MN, and, with radioimmunoassays, measured allergens of Aspergillus fumigatus, Thermoactinomyces vulgaris, Micropolyspori faeni, short ragweed, rye grass group I pollen, Alternaria (Alt-1), Dermatophagoides sp. Lepidoglyphus destructor, common insect allergen, mouse urine, rat urine, and cattle epithelium. The most abundant allergen present was A. fumigatus followed by L. destructor. This study provides initial data on barn aerobiology and demonstrates for the first time the abundance of L. destructor allergens in North American dairy barns. More comprehensive study of barns, poultry houses, confinement houses for swine, and other agricultural environments from various geographic locations is needed to define the allergen levels to which millions of farm workers are exposed each day. While most of the allergens were expected, the presence of airborne allergens reactive with antisera to Dermatophagoides suggests indirectly that substantial amounts of pyroglyphid mites are present in some barns

  18. Low Multilinear Rank Approximation of Tensors and Application in Missing Traffic Data

    Directory of Open Access Journals (Sweden)

    Huachun Tan

    2014-02-01

    Full Text Available The problem of missing data in multiway arrays (i.e., tensors is common in many fields such as bibliographic data analysis, image processing, and computer vision. We consider the problems of approximating a tensor by another tensor with low multilinear rank in the presence of missing data and possibly reconstructing it (i.e., tensor completion. In this paper, we propose a weighted Tucker model which models only the known elements for capturing the latent structure of the data and reconstructing the missing elements. To treat the nonuniqueness of the proposed weighted Tucker model, a novel gradient descent algorithm based on a Grassmann manifold, which is termed Tucker weighted optimization (Tucker-Wopt, is proposed for guaranteeing the global convergence to a local minimum of the problem. Based on extensive experiments, Tucker-Wopt is shown to successfully reconstruct tensors with noise and up to 95% missing data. Furthermore, the experiments on traffic flow volume data demonstrate the usefulness of our algorithm on real-world application.

  19. Measuring financial well-being in cancer prevention research: Results from the Money-Health Connection Study

    Science.gov (United States)

    Dr. Reginald Tucker-Seeley joined the faculty at the University of Southern California (USC) Leonard Davis School of Gerontology in June 2017. Prior to joining USC, Dr. Tucker-Seeley was an Assistant Professor at the Dana-Farber Cancer Institute (DFCI) and the Harvard T.H. Chan School of Public Health (HSPH). He completed master and doctoral degrees at HSPH and a postdoctoral fellowship in cancer prevention and control at HSPH and DFCI. Dr. Tucker-Seeley’s research focuses primarily on social determinants of health, such as the association between the neighborhood environment and health behavior; and on individual-level socioeconomic determinants of multi-morbidity, mortality, self-rated health, and health self-efficacy. His current work focuses on financial well-being across the cancer continuum, from prevention to end-of-life care. He has received R21 and K01 grants from the National Cancer Institute (NCI) to develop measures of financial well-being at two points along the cancer continuum: prevention and following diagnosis. He was also funded by the Academy Health/Aetna Foundation Scholars in Residence Fellowship Program to develop measures of neighborhood economic well-being. Dr. Tucker-Seeley’s research has been published in journals such as the American Journal of Public Health, Preventive Medicine, Journal of National Cancer Institute, Cancer Causes and Control, and the American Journal of Preventive Medicine. Dr. Tucker-Seeley is also committed to community service that targets the elimination of health disparities. He served for three years on the Rhode Island Commission for Health Advocacy and Equity. Based on his experience on this Commission, Dr. Tucker-Seeley developed a new course at HSPH called “Measuring and Reporting Health Disparities;” and in 2016, he received the HSPH teaching award for this course.

  20. Local Geoid Determination Using the Global Positioning System

    Science.gov (United States)

    1988-09-01

    Positioning System by Ma, Wei-Ming September 1988 Co-Advisor: Kandiah Jeyapalan Co-Advisor: Stevens P. Tucker Approved for public release; distribution is... Jeyapalan and Stevens P. Tucker, my thesis advisors, for their dedicated assistance and guidance during the study. Without their encouragement...method of collocation is [ Jeyapalan , 1977]: x = A*X+S +n +O.S q q P where x the vector of the observation (x = Ah - N0(X,Y,Z) - H) A a given rectangular

  1. Occurrence, diversity and pattern of damage of Oplostomus species (Coleoptera: Scarabaeidae), honey bee pests in Kenya

    Science.gov (United States)

    Several arthropod pests including the hive beetles Aethina tumida and Oplostomus haroldi and the ectoparasite Varroa destructor have recently been identified as associated with honey bee colonies in Kenya. Here, we report the first documentation of O. fuligineus in Kenya, a related scarab of O. haro...

  2. On the abundance of Dermatophagoides pteronyssinus (Trouessart, 1897) (Pyroglyphidae: Acarina) in house dust

    NARCIS (Netherlands)

    Bronswijk, van J.E.M.H.; Schoonen, J.M.C.P.; Berlie, M.A.F.; Lukoschus, F.S.

    1971-01-01

    The dominance of the Pyroglyphidae in house dust has been influenced by a number of factors. The humidity in houses dropped recently to such an extent that only Pyroglyphidae can survive. When temperature and relative humidity are favorable for Acarus siro and Glycyphagus destructor as well as

  3. Author Details

    African Journals Online (AJOL)

    Abdelkader, Faten Ben. Vol 64, No 1 (2016): Special Edition - Articles Particularité du traitement à l'acide formique de varroa destructor (Acari, Varroidae), parasite d'apis mellifera dans les conditions tunisiennes. Abstract. ISSN: 0378-9721. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for ...

  4. Successful reproduction of unmated Tropilaelaps mercedesae and its implication on mite population growth in Apis mellifera colonies

    Science.gov (United States)

    Highly hygienic colonies are known to reduce the reproductive potential of Varroa destructor. For Tropilaelaps mercedesae, information on how bee behavior may influence the mite’s reproductive potential is currently unknown. In this study, we assessed the influence of recapping on the reproduction o...

  5. Statistical methods to quantify the effect of mite parasitism on the probability of death in honey bee colonies

    Science.gov (United States)

    Varroa destructor is a mite parasite of European honey bees, Apis mellifera, that weakens the population, can lead to the death of an entire honey bee colony, and is believed to be the parasite with the most economic impact on beekeeping. The purpose of this study was to estimate the probability of ...

  6. Responses to Varroa by honey bees with different levels of Varroa Sensitive Hygiene

    Science.gov (United States)

    The mite-resistance trait called suppression of mite reproduction (SMR) is a form of hygienic behavior that we have named varroa sensitive hygiene (VSH). With VSH, adult worker bees (Apis mellifera) disrupt the population growth of parasitic mites (Varroa destructor) by removing mite-infested bee p...

  7. Simplified methods of evaluating colonies for levels of Varroa Sensitive Hygiene (VSH)

    Science.gov (United States)

    Varroa sensitive hygiene (VSH) is a trait of honey bees, Apis mellifera, that supports resistance to varroa mites, Varroa destructor. Components of VSH were evaluated to identify simple methods for selection of the trait. Varroa mite population growth was measured in colonies with variable levels of...

  8. Expression of varroa sensitive hygiene (VSH) in commercial VSH honey bees (Hymenoptera: Apidae)

    Science.gov (United States)

    We tested six commercial sources of honey bees (Apis mellifera L.) that were bred to include the trait of varroa sensitive hygiene (VSH). VSH confers resistance to the parasitic mite Varroa destructor Anderson & Trueman. Queens from these sources were established in colonies which later were measure...

  9. High-Resolution Linkage Analyses to Identify Genes That Influence Varroa Sensitive Hygiene Behavior in Honey Bees.

    Science.gov (United States)

    Varroa mites (V. destructor) are a major threat to honey bees (Apis melilfera) and beekeeping worldwide and likely lead to colony decline if colonies are not treated. Most treatments involve chemical control of the mites; however, Varroa has evolved resistance to many of these miticides, leaving be...

  10. Differential gene expression associated with honey bee grooming behavior in response to varroa mites

    Science.gov (United States)

    Honey bee (Apis mellifera) grooming behavior is an important mechanism of resistance against the parasitic mite Varroa destructor. This research was conducted to study associations between grooming behavior and the expression of selected immune, neural, detoxification, developmental and health-relat...

  11. Seminario C++, parte 1

    OpenAIRE

    Cachero Castro, Cristina; Ponce de León Amador, Pedro José

    2007-01-01

    Este seminario trata sobre principios de orientación a objetos con C++. Para comprender mejor sus contenidos, se debe tener un conocimiento básico sobre programación estructurada con C++ o C. Clases en C++. Operaciones set/get/is. Tipo Referencia (&). El puntero 'this'. Los constructores. El destructor.

  12. La eliminación higiénica de la cría congelada no predice caracteres de resistencia ante Varroa en las poblaciones no seleccionadas

    NARCIS (Netherlands)

    Leclercq, Gil; Blacquière, Tjeerd; Gengler, Nicolas; Francis, Frédéric

    2018-01-01

    In honey bees (Apis mellifera L.), hygienic behavior of workers against Varroa destructor provides the colonies with some resistance to this parasite. The removal of freeze-killed brood (FKB) has often been used as a proxy to assess the removal of Varroa-infested brood. The question is whether this

  13. Effectieve bestrijding van varroa (Tweede, licht gewijzigde druk)

    NARCIS (Netherlands)

    Cornelissen, B.; Blacquière, T.; Steen, van der J.J.M.

    2013-01-01

    De varroa mijtziekte (Varroa destructor) is de belangrijkste bedreiging van de Europese honingbij. Wintersterfte van honingbijen is in de meeste gevallen toe te schrijven aan deze ziekte. Deze tweede, licht gewijzigde druk biedt informatie over de biologie van varroa, de effecten van varroa op

  14. Varroa Sensitive Hygiene contributes to naturally selected varroa resistance in honey bees

    NARCIS (Netherlands)

    Panziera, Delphine; Langevelde, van Frank; Blacquière, Tjeerd

    2017-01-01

    The parasitic mite Varroa destructor is a serious threat for western honey bee colonies and beekeepers are compelled to control it to keep their colonies healthy. Yet, by controlling varroa no resistance to the parasite can evolve. As a trial, honey bee colonies have been left untreated in

  15. Effectieve bestrijding van varroa

    NARCIS (Netherlands)

    Cornelissen, B.; Blacquiere, T.; Steen, van der J.J.M.

    2010-01-01

    De varroa mijtziekte (Varroa destructor) is de belangrijkste bedreiging van de Europese honingbij. Wintersterfte van honingbijen is in de meeste gevallen toe te schrijven aan deze ziekte. Deze brochure van de WUR biedt informatie over de biologie van varroa, de effecten van varroa op honingbijen en

  16. Effect varroa op volksgrootte pas zichtbaar als het te laat is?

    NARCIS (Netherlands)

    Dooremalen, van C.; Cornelissen, B.; Langevelde, van F.

    2014-01-01

    De parasitaire mijt Varroa destructor is altijd en overal aanwezig in volken van onze honingbijen. Varroa verkot het leven van de volwassen bij, wat resulteert in een verhoogde kans op wintersterfte. Ondanks leen relatief geringe wintersterfte in 2012-2013 en 2013-2014 is het identificeren van een

  17. Potential impacts of alien freshwater crayfish in South Africa | de ...

    African Journals Online (AJOL)

    The habitat preferences and life history characteristics of four alien species of freshwater crayfish (Cherax tenuimanus, C. destructor, C. quadricarinatus and Procambarus clarkii) are reviewed. The potential impact of these species on South African freshwater ecosystems is assessed and the desirability of allowing their ...

  18. Impact of temperatures to Hessian Fly resistance of selected wheat cultivars in the Great Plains Region

    Science.gov (United States)

    Changes in temperature can result in fundamental changes in plant physiology. This study investigated the impact of different temperatures from 14 to 26 °C on the resistance or susceptibility to the Hessian fly, Mayetiola destructor, of selected wheat cultivars that are either currently popular in ...

  19. Ecology, life history and management of tropilaelaps mites

    Science.gov (United States)

    Parasitic mites are the major threat of the Western honey bee, Apis mellifera. For much of the world, Varroa destructor single-handedly inflicts unsurmountable problems to A. mellifera beekeeping. However, A. mellifera in Asia is also faced with another genus of destructive parasitic mite, Tropilae...

  20. Reproductive biology of varroa mites in colonies of Africanized honey bees

    NARCIS (Netherlands)

    Calderon Fallas, R.A.

    2009-01-01

    We investigated the reproductive biology of V. destructor in Africanized honeybees (AHB) in Central American conditions, specifically in Costa Rica. Attention was paid to mite fertility and production of viable female mites in worker and drone brood cells. Other reproduction parameters, like

  1. Emerging and re-emerging viruses of the honey bee (Apis mellifera L.).

    Science.gov (United States)

    Genersch, Elke; Aubert, Michel

    2010-01-01

    Until the late 1980s, specific viral infections of the honey bee were generally considered harmless in all countries. Then, with the worldwide introduction of the ectoparasite mite Varroa destructor, beekeepers encountered increasing difficulties in maintaining their colonies. Epidemiological surveys and laboratory experiments have demonstrated that the newly acquired virulence of several viruses belonging to the family Dicistroviridae (acute bee paralysis virus, Kashmir bee virus and Israeli acute paralysis virus) in Europe and the USA had been observed in relation with V. destructor acting as a disseminator of these viruses between and within bee colonies and as an activator of virus multiplication in the infected individuals: bee larvae and adults. Equal emphasis is given to deformed wing virus (DWV) belonging to the Iflaviridae. Overt outbreaks of DWV infections have been shown to be linked to the ability of V. destructor to act not only as a mechanical vector of DWV but also as a biological vector. Its replication in mites prior to its vectoring into pupae seemed to be necessary and sufficient for the induction of a overt infection in pupae developing in non-viable bees with deformed wings. DWV in V. destructor infested colonies is now considered as one of the key players of the final collapse. Various approaches for combating bee viral diseases are described: they include selection of tolerant bees, RNA interference and prevention of new pathogen introduction. None of these approaches are expected to lead to enhanced bee-health in the short term. © INRA, EDP Sciences, 2010.

  2. Browse Title Index - AJOL

    African Journals Online (AJOL)

    Items 5101 - 5150 of 11090 ... Vol 5, No 5 (2006), Field evaluation of selected formulations of ... virus (DWV) in honeybees (Apis mellifera L.) and mite (Varroa destructor) in Turkey, Abstract PDF ... length polymorphism (AFLP) analysis of genetic diversity and ... Vol 10, No 66 (2011), Foliar zinc fertilization improves the zinc ...

  3. Transcriptomic analyses of the secreted proteins from the salivary glands of the wheat midge larvae

    Science.gov (United States)

    Both the wheat midge (Sitodiplosis mosellana) and the Hessian fly (Mayetiola destructor) belong to a group of insects called gall midges (Diptera: Cecidomyiidae) and both are destructive pests of wheat. From Hessian fly larvae, a large number of genes have been identified to encode Secreted Salivary...

  4. Parasite-host interactions between the Varroa mite and the honey bee : a contribution to sustainable Varroa control

    NARCIS (Netherlands)

    Calis, J.N.M.

    2001-01-01

    Introduction

    Varroa mites as parasites of honey bees

    Varroa destructor (Anderson & Trueman, 2000), is the most important pest of European races of the Western honey bee, Apis mellifera L., weakening bees

  5. The Tropilaelaps mites threat: Observations of their reproductive success

    Science.gov (United States)

    Tropilaelaps spp. are more successful parasitic mites of Apis mellifera than Varroa destructor in Asia (Burgett et al., Bee World 64:25-28). We sought explanations to this success by assessing their fecundity on European bees in three short experiments using the mite transfer technique: 1) fecundity...

  6. Development of molecular tools for honeybee virus research: the ...

    African Journals Online (AJOL)

    Increasing knowledge of the association of honeybee viruses with other honeybee parasites, primarily the ectoparasitic mite Varroa destructor, and their implication in the mass mortality of honeybee colonies, has resulted in increasing awareness and interest in honeybee viruses. In addition the identification, monitoring and ...

  7. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Amitraz is formamidine pesticide widely used as insecticide and acaricide. In veterinary medicine, amitraz has important uses against ticks, mites and lice on animals. Also, amitraz is used in apiculture to control Varroa destructor. It this study, the alkaline Comet assay was used to evaluate DNA damaging effects of amitraz ...

  8. Bee Mite ID - an online resource on identification of mites associated with bees of the World

    Science.gov (United States)

    Parasitic mites are known to be a factor in recent declines in bee pollinator populations. In particular, Varroa destructor, an introduced parasite and disease vector, has decimated colonies of the western honey bee, one of the most important agricultural pollinators in the world. Further, global tr...

  9. Differential responses to DWV infection in honey bees: A case of tolerance or resistance?

    Science.gov (United States)

    Honey bees contend with a variety of abiotic and biotic stressors, and this has led to high and likely unsustainable annual colony mortality. The ectoparasitic mite Varroa destructor is the biggest threat affecting honey bee health in large part because of the viruses that mites vector while feeding...

  10. A diverse range of novel RNA viruses in geographically distinct honey bee populations

    NARCIS (Netherlands)

    Remnant, Emily J.; Shi, Mang; Buchmann, Gabriele; Blacquière, Tjeerd; Holmes, Edward C.; Beekman, Madeleine; Ashe, Alyson

    2017-01-01

    Understanding the diversity and consequences of viruses present in honey bees is critical for maintaining pollinator health and managing the spread of disease. The viral landscape of honey bees (Apis mellifera) has changed dramatically since the emergence of the parasitic mite Varroa destructor,

  11. Delineating shallow ground water irrigated areas in the Atankwidi ...

    African Journals Online (AJOL)

    user

    Basin Lan Use/Land Cover (LULC) and irrigated area Mapping using. Continuous Streams of MODIS Data. Remote Sensing Environ.,. 95(3): 317-341. Neckel H, Labs D (1984). The solar radiation between 3300 and 12500. A. Solar Phys., 90: 205-258. Tucker CJ, Grant DM, Dykstra JD (2005). NASA's global orthorectified.

  12. Moving in the Anthropocene: Global reductions in terrestrial mammalian movements

    DEFF Research Database (Denmark)

    Tucker, Marlee A.; Böhning-Gaese, Katrin; Fagan, William F.

    2018-01-01

    Until the past century or so, the movement of wild animals was relatively unrestricted, and their travels contributed substantially to ecological processes. As humans have increasingly altered natural habitats, natural animal movements have been restricted. Tucker et al. examined GPS locations...

  13. 1 Ammonia Concentrations in Different Aquaculture 2

    African Journals Online (AJOL)

    Administrator

    Introduction. Most studies have shown that the best feed for optimal fish production in aquaculture is one rich in high amount of protein. The amount of protein in the ..... Aquatic Science, Florida Coop, Ext. Serv. FA-16, 4 pp. Hargreaves J. A. and Tucker C. S. (2004). Managing. Ammonia in Fish Ponds. SRAC Publication Fact.

  14. Multivariate statistical process control of batch processes based on three-way models

    NARCIS (Netherlands)

    Louwerse, D. J.; Smilde, A. K.

    2000-01-01

    The theory of batch MSPC control charts is extended and improved control charts an developed. Unfold-PCA, PARAFAC and Tucker3 models are discussed and used as a basis for these charts. The results of the different models are compared and the performance of the control charts based on these models is

  15. Evaluating Alternatives for Drinking Water at Deployed Locations

    Science.gov (United States)

    2006-03-01

    Tucker and Sands, 1999; Beering , 2002). 1986 Plutonium was found in the New York city drinking water system. Though the concentrations were...based approach called Hazard Analysis and Critical Control Point ( HACCP ). This approach holds that avoidance is practical and effective where other

  16. Combinatorial Integer Labeling Thorems on Finite Sets with an Application to Discrete Systems of Nonlinear Equations

    NARCIS (Netherlands)

    van der Laan, G.; Talman, A.J.J.; Yang, Z.F.

    2007-01-01

    Tucker's well-known combinatorial lemma states that for any given symmetric triangulation of the n-dimensional unit cube and for any integer labeling that assigns to each vertex of the triangulation a label from the set f§1;§2; ¢ ¢ ¢ ;§ng with the property that antipodal vertices on the boundary of

  17. The susceptibilities in the spin-S Ising model

    International Nuclear Information System (INIS)

    Ainane, A.; Saber, M.

    1995-08-01

    The susceptibilities of the spin-S Ising model are evaluated using the effective field theory introduced by Tucker et al. for studying general spin-S Ising model. The susceptibilities are studied for all spin values from S = 1/2 to S = 5/2. (author). 12 refs, 4 figs

  18. A Comparison of Four Linear Equating Methods for the Common-Item Nonequivalent Groups Design Using Simulation Methods. ACT Research Report Series, 2013 (2)

    Science.gov (United States)

    Topczewski, Anna; Cui, Zhongmin; Woodruff, David; Chen, Hanwei; Fang, Yu

    2013-01-01

    This paper investigates four methods of linear equating under the common item nonequivalent groups design. Three of the methods are well known: Tucker, Angoff-Levine, and Congeneric-Levine. A fourth method is presented as a variant of the Congeneric-Levine method. Using simulation data generated from the three-parameter logistic IRT model we…

  19. Baseline and Multimodal UAV GCS Interface Design

    Science.gov (United States)

    2013-07-01

    complete a computerized version of the NASA - TLX assessment of perceived mental workload. 2.3 Results The baseline condition ran smoothly and with...System MALE Medium-altitude, Long-endurance NASA - TLX NASA Task Load Index SA Situation Awareness TDT Tucker Davis Technologies UAV Uninhabited Aerial

  20. A Hot White Dwarf Luminosity Function from the Sloan Digital Sky Survey

    Science.gov (United States)

    2009-01-01

    Berro, E., Torres, S., & Catalan, S. 2008, ApJ, 682, L109 Ivezic, Z., Lupton, R. H., Schlegel, D., et al. 2004, Astron. Nachrichten , 325, 583...et al. 2002, AJ, 123, 485 Tucker, D., Kent, S., Richmond, M. W., et al. 2006, Astron. Nachrichten , 327, 821 Vennes, S. 1999, ApJ, 525, 995 Vennes, S

  1. Strategy for the Long Haul. Special Operations Forces: Future Challenges and Opportunities

    Science.gov (United States)

    2008-01-01

    College, 2006); and David Tucker and Chris- topher Lamb , “Restructuring Special Operations Forces for Emerging Threats, NDU Strategic Forum, January...Secretary of Defense Gates, SOCOM commander Admiral Eric Olson, and Assistant Secretary of Defense for SOLIC/IC Michael Vickers. See: Stew Mag- nuson

  2. Comparison of the Relationship between Words Retained and Intelligence for Three Instructional Strategies among Students with Below-Average IQ

    Science.gov (United States)

    Burns, Matthew K.; Boice, Christina H.

    2009-01-01

    The current study replicated MacQuarrie, Tucker, Burns, and Hartman (2002) with a sample of 20 students who had been identified with a disability and had an IQ score that was between 1 and 3 standard deviations below the normative mean. Each student was taught 27 words from the Esperanto International Language with the following conditions: (a)…

  3. Lives of a Cell: 40 Years Later, A Third Interpretation

    Centers for Disease Control (CDC) Podcasts

    2015-06-16

    Reginald Tucker reads an abridged version of the article Lives of a Cell: 40 Years Later, A Third Interpretation.  Created: 6/16/2015 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 6/18/2015.

  4. Threat from Emerging Vectorborne Viruses

    Centers for Disease Control (CDC) Podcasts

    2016-06-09

    Reginald Tucker reads an abridged version of the commentary by CDC author Ronald Rosenberg, Threat from Emerging Vectorborne Viruses.  Created: 6/9/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 6/9/2016.

  5. Factors Related to Fetal Death in Pregnant Women with Cholera, Haiti, 2011–2014

    Centers for Disease Control (CDC) Podcasts

    2016-03-14

    Reginald Tucker reads an abridged version of the EID article Factors Related to Fetal Death in Pregnant Women with Cholera, Haiti, 2011–2014.  Created: 3/14/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 3/14/2016.

  6. Bat Flight and Zoonotic Viruses

    Centers for Disease Control (CDC) Podcasts

    2014-05-30

    Reginald Tucker reads an abridged version of the EID perspective Bat Flight and Zoonotic Viruses.  Created: 5/30/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 6/2/2014.

  7. Macrozooplankton biomass in the deep scattering layer of the Indian EEZ.

    Digital Repository Service at National Institute of Oceanography (India)

    Karuppasamy, P.K.; Balu, S.; Persis, V.

    . 1988. Oceanographic atlas of the Exclusive Economic Zone of India. NIO. Ref. N. 1301, Figs. 1-44. Tucker, G. H. 1951. Relation of fishes and other organisms to the scattering of underwater sound. J. Mar. Res., 10(2): 215- 238. Vannuci, M. and D. Navas...

  8. Journal of Special Operations Medicine, Volume 6, Edition 4

    Science.gov (United States)

    2006-01-01

    Gay Thompson worked on the First Edition as the Managing Editor and will be doing the same this time. Dr. Les Fenton , who recently retired from... cosmetic surgery: Low dosage ketamine-diazepam anesthesia. Laryngoscope 1978;88: 1709-12. 52. Tucker MR, Hann JR, Phillips CL, et al. Subanesthetic

  9. Usnea christhinae spec. nov. from South America

    Directory of Open Access Journals (Sweden)

    Jan Bystrek

    2014-08-01

    Full Text Available A new lichen species Usnea christhinae Bystrek is described from the Patagonia Andes, the reserve upon lake Onelli in the National Park Los Glaciares. It belongs to subgenus Protousnea Motyka emend. Bystrek and is closely related to U. cavernosa Tucker.

  10. Hydrocarbon source rock potential evaluation of the Late Paleocene ...

    Indian Academy of Sciences (India)

    63

    research is available on its source rock potential evaluation at Nammal Gorge Section in the Salt. Range, Potwar Basin .... methods of Tucker (2003) and Assaad (2008) have been followed. A total of fifteen ..... Business Media. Baker D M, Lillie ...

  11. Download this PDF file

    African Journals Online (AJOL)

    JONATHAN

    The Lugbara are a Sudanic-speaking people and are members of the Moru-Madi sub-group of the Eastern Sudanic group (Tucker,. 1940). They believe that Adronga, the Supreme Being created the world. He created Gborogboro (male being) and Meme (female being). Adronga is conceived in two ways: as God in the sky,.

  12. Automated Assessment of Postural Stability (AAPS)

    Science.gov (United States)

    2016-10-01

    performed a battery of standard clinical tests of dynamic posture, whereas the fourth subject performed the stereotyped postures (e.g. movements restricted...Processing & Control [2] Napoli A, Ward C, Glass S, Tucker C, Obeid I (2016) “Automated Assessment of Postural Stability System,” IEEE Engineering in

  13. Viewpoint: Transatlantic Scholarship on Victorian Literature and Culture

    Directory of Open Access Journals (Sweden)

    Isobel Armstrong

    2009-11-01

    Full Text Available This viewpoint offers a comparison of recent British and American criticism of Victorian literature and culture, encompassing Dickens, Tennyson, the epic and ethical criticism. Discussion centres on recent studies by Sally Ledger, Rosemarie Bodenheimer, Cornelia Pearsall, Kirstie Blair, Simon Dentith, Herbert Tucker, Andrew Miller and Mike Sanders.

  14. Application of Parallel Hierarchical Matrices and Low-Rank Tensors in Spatial Statistics and Parameter Identification

    KAUST Repository

    Litvinenko, Alexander

    2018-03-12

    Part 1: Parallel H-matrices in spatial statistics 1. Motivation: improve statistical model 2. Tools: Hierarchical matrices 3. Matern covariance function and joint Gaussian likelihood 4. Identification of unknown parameters via maximizing Gaussian log-likelihood 5. Implementation with HLIBPro. Part 2: Low-rank Tucker tensor methods in spatial statistics

  15. The Geometric Mean Value Theorem

    Science.gov (United States)

    de Camargo, André Pierro

    2018-01-01

    In a previous article published in the "American Mathematical Monthly," Tucker ("Amer Math Monthly." 1997; 104(3): 231-240) made severe criticism on the Mean Value Theorem and, unfortunately, the majority of calculus textbooks also do not help to improve its reputation. The standard argument for proving it seems to be applying…

  16. Gum biopsy

    Science.gov (United States)

    ... Hupp JR, Ellis E, Tucker MR, eds. Contemporary Oral and Maxillofacial Surgery . 6th ed. St Louis, MO: Elsevier Mosby; 2014: ... Wein RO, Weber RS. Malignant neoplasms of the oral cavity. In: Flint PW, ... & Neck Surgery . 6th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap ...

  17. On Association Measures for Continuous Variables and Correction for Chance

    NARCIS (Netherlands)

    Warrens, Matthijs J.

    2015-01-01

    This paper studies correction for chance for association measures for continuous variables. The set of linear transformations of Pearson's product-moment correlation is used as the domain of the correction for chance function. Examples of measures in this set are Tucker's congruence coefficient,

  18. Tooth extraction

    Science.gov (United States)

    ... In: Kademani D, Tiwana PS, eds. Atlas of Oral and Maxillofacial Surgery . St Louis, MO: Elsevier Saunders; 2016:chap 10. ... Hupp JR, Ellis E, Tucker MR, eds. Contemporary Oral and Maxillofacial Surgery . 6th ed. Philadelphia, PA: Elsevier Mosby; 2014:chap ...

  19. Flipped Classroom versus Traditional Textbook Instruction: Assessing Accuracy and Mental Effort at Different Levels of Mathematical Complexity

    Science.gov (United States)

    Mattis, Kristina V.

    2015-01-01

    Flipped classrooms are an instructional technology trend mostly incorporated in higher education settings, with growing prominence in high school and middle school (Tucker in Leveraging the power of technology to create student-centered classrooms. Corwin, Thousand Oaks, 2012). Flipped classrooms are meant to effectively combine traditional and…

  20. Kiiksuga kangelased / Mele Pesti

    Index Scriptorium Estoniae

    Pesti, Mele, 1979-

    2006-01-01

    USA roadmovie tüüpi sisukad mängufilmid "Väike Miss Päikesepaiste" ("Little Miss Sunshine"; režissöörid Jonathan Dayton ja Valerie Faris, peaosas 10-aastane Abigail Breslin) ja "Transamerica" ( režissöör Duncan Tucker, peaosas Felicity Huffman)

  1. Annual Review of Applied Linguistics, Volume 5, 1984.

    Science.gov (United States)

    Kaplan, Robert B., Ed.

    This volume of the annual review includes introductory remarks by G. Richard Tucker and these papers: "Current Issues in Bilingualism: An Update of Directions in Research" (Braj B. Kachru); "Psycholinguistics: Application. The Writing System as a Native Language for the Deaf" (Danny D. Steinberg); "Sociolinguistics: Theory" (Monica Heller);…

  2. 78 FR 21927 - Notice of Commission Staff Attendance

    Science.gov (United States)

    2013-04-12

    ... activities of the Southern Company Services, Inc.: Southeastern Regional Transmission Planning (SERTP... above-referenced meeting will be held at: Georgia Transmission Corporation (GTC) Headquarters--Tucker... proceedings: Docket No. ER13-908, Alabama Power Company et al. Docket No. ER13-913, Ohio Valley Electric...

  3. 77 FR 73645 - Notice of Commission Staff Attendance

    Science.gov (United States)

    2012-12-11

    ... Southern Company Services, Inc.: Southeastern Regional Transmission Planning Process (SERTP) Interim... meeting will be held at: Georgia Transmission Corporation (GTC) Headquarters--Tucker, Georgia The above... proceedings: Docket No. ER12-337, Mississippi Power Company For more information, contact Valerie Martin...

  4. Can a sample of Landsat sensor scenes reliably estimate the global extent of tropical deforestation?

    Science.gov (United States)

    R. L. Czaplewski

    2003-01-01

    Tucker and Townshend (2000) conclude that wall-to-wall coverage is needed to avoid gross errors in estimations of deforestation rates' because tropical deforestation is concentrated along roads and rivers. They specifically question the reliability of the 10% sample of Landsat sensor scenes used in the global remote sensing survey conducted by the Food and...

  5. Browse Title Index

    African Journals Online (AJOL)

    Items 51 - 100 of 164 ... Vol 18, No 1 (2006), Lions, leopards and liminal spaces:Representations of Biosociality in the Writings of Katy Payne, Linda Tucker and Gillian van Houten, Abstract. W Woodward. Vol 19, No 1 (2007), Making Space for New Voices: The Politics of Editing in South Africa, Abstract. E Bregin. Vol 15, No 2 ...

  6. Author Details

    African Journals Online (AJOL)

    Abstract · Vol 15, No 2 (2003) - Articles Jim comes from Jo'burg': Regionalised Identities and Social Comedy in Zakes Mda's The Heart of Redness Abstract · Vol 18, No 1 (2006) - Articles Lions, leopards and liminal spaces:Representations of Biosociality in the Writings of Katy Payne, Linda Tucker and Gillian van Houten

  7. 78 FR 78477 - Qualification of Drivers; Exemption Applications; Vision

    Science.gov (United States)

    2013-12-26

    ...) James T. Sullivan (KY) David C. Sybesma (ID) Robert N. Taylor (OR) Scott A. Taylor (WV) Temesgn H. Teklezig (WA) Matthew K. Tucker (MN) Victor H. Vera (TX) Stephen D. Vice (KY) Larry J. Waldner (SD) Karl A...) Jerry L. Schroder (IL) Gerald J. Shamla (MN) Stephen E. Shields (KY) Peter M. Shirk (PA) William C...

  8. Structural optimization

    CERN Document Server

    MacBain, Keith M

    2009-01-01

    Intends to supplement the engineer's box of analysis and design tools making optimization as commonplace as the finite element method in the engineering workplace. This title introduces structural optimization and the methods of nonlinear programming such as Lagrange multipliers, Kuhn-Tucker conditions, and calculus of variations.

  9. Does nitrogen and sulfur deposition affect forest productivity?

    Science.gov (United States)

    Brittany A. Johnson; Kathryn B. Piatek; Mary Beth Adams; John R. Brooks

    2010-01-01

    We studied the effects of atmospheric nitrogen and sulfur deposition on forest productivity in a 10-year-old, aggrading forest stand at the Fernow Experimental Forest in Tucker County, WV. Forest productivity was expressed as total aboveground wood biomass, which included stem and branch weight of standing live trees. Ten years after stand regeneration and treatment...

  10. Zombies—A Pop Culture Resource for Public Health Awareness

    Centers for Disease Control (CDC) Podcasts

    2013-04-24

    Reginald Tucker reads an abridged version of the Emerging Infectious Diseases Another Dimension, Zombies—A Pop Culture Resource for Public Health Awareness.  Created: 4/24/2013 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 4/24/2013.

  11. Quinto Tiberio Angelerio and New Measures for Controlling Plague in 16th-Centruy Alghero, Sardinia

    Centers for Disease Control (CDC) Podcasts

    2013-10-28

    Reginald Tucker reads an abridged version of the Emerging Infectious Diseases’ historical Review, Quinto Tiberio Angelerio and New Measures for Controlling Plague in 16th -Centruy Alghero, Sardinia.  Created: 10/28/2013 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 10/30/2013.

  12. Lessons from the History of Quarantine, from Plague to Influenza A

    Centers for Disease Control (CDC) Podcasts

    2013-05-08

    Reginald Tucker reads an abridged version of the Emerging Infectious Diseases’ Historical Review, Lessons from the History of Quarantine, from Plague to Influenza A.  Created: 5/8/2013 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 5/15/2013.

  13. Determinants and Drivers of Infectious Disease Threat Events in Europe

    Centers for Disease Control (CDC) Podcasts

    2016-05-04

    Reginald Tucker reads an abridged version of the article, Determinants and Drivers of Infectious Disease Threat Events in Europe.  Created: 5/4/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 5/4/2016.

  14. A Smooth Newton Method for Nonlinear Programming Problems with Inequality Constraints

    Directory of Open Access Journals (Sweden)

    Vasile Moraru

    2012-02-01

    Full Text Available The paper presents a reformulation of the Karush-Kuhn-Tucker (KKT system associated nonlinear programming problem into an equivalent system of smooth equations. Classical Newton method is applied to solve the system of equations. The superlinear convergence of the primal sequence, generated by proposed method, is proved. The preliminary numerical results with a problems test set are presented.

  15. Factors Associated with Teen Pregnancy in sub-Saharan Africa: A ...

    African Journals Online (AJOL)

    AJRH Managing Editor

    Therefore, it is important to test the influence of household- ...... South African Journal of Psychology 2010;. 40(1):18-31. ... Reynolds HW, Wong EL, Tucker H. Adolescents' use of maternal .... Eyakuze A, Salim A. The state of East Africa 2012:.

  16. Life Cycle Assessment | National Agricultural Library

    Science.gov (United States)

    NO-NP (5) Apply NO-NP filter soybean (5) Apply soybean filter accounting (4) Apply accounting filter filter winter wheat (1) Apply winter wheat filter work process (1) Apply work process filter Filter by using the Tucker Renewable Natural Gas (RNG) Thermochemical conversion process. The two co-products are

  17. An Evaluation of Kernel Equating: Parallel Equating with Classical Methods in the SAT Subject Tests[TM] Program. Research Report. ETS RR-09-06

    Science.gov (United States)

    Grant, Mary C.; Zhang, Lilly; Damiano, Michele

    2009-01-01

    This study investigated kernel equating methods by comparing these methods to operational equatings for two tests in the SAT Subject Tests[TM] program. GENASYS (ETS, 2007) was used for all equating methods and scaled score kernel equating results were compared to Tucker, Levine observed score, chained linear, and chained equipercentile equating…

  18. The online behavioural advertising icon: Two user studies

    NARCIS (Netherlands)

    van Noort, G.; Smit, E.G.; Voorveld, H.A.M.; Rosengren, S.; Dahlén, M.; Okazaki, S.

    2013-01-01

    New Internet technologies provide the possibility of automated tracking of consumers’ Internet behaviour. Such tracking is used to create user profiles for the purpose of displaying advertisements that fit the interest of these individuals (e.g., Goldfarb and Tucker 2011; McDonald and Cranor 2010).

  19. Bootstrap confidence intervals for three-way methods

    NARCIS (Netherlands)

    Kiers, Henk A.L.

    Results from exploratory three-way analysis techniques such as CANDECOMP/PARAFAC and Tucker3 analysis are usually presented without giving insight into uncertainties due to sampling. Here a bootstrap procedure is proposed that produces percentile intervals for all output parameters. Special

  20. Some fossil species of Babylonia seen in ultraviolet light, with description of a new species (Mollusca, Gastropoda)

    NARCIS (Netherlands)

    Regteren, van C.O.; Gittenberger, E.

    1972-01-01

    When preparing a revision of the genus Babylonia for "Indo-Pacific Mollusca", edited by Dr. R. Tucker Abbott, we tried ultraviolet light to see the outline of the colour-pattern of some fossil species. Later on we saw the same method described by Mrs. Katherine Krueger (1971). Dr. H. E. Coomans of

  1. Presence of Apis Rhabdovirus-1 in Populations of Pollinators and Their Parasites from Two Continents.

    Science.gov (United States)

    Levin, Sofia; Galbraith, David; Sela, Noa; Erez, Tal; Grozinger, Christina M; Chejanovsky, Nor

    2017-01-01

    The viral ecology of bee communities is complex, where viruses are readily shared among co-foraging bee species. Additionally, in honey bees ( Apis mellifera ), many viruses are transmitted - and their impacts exacerbated - by the parasitic Varroa destructor mite. Thus far, the viruses found to be shared across bee species and transmitted by V. destructor mites are positive-sense single-stranded RNA viruses. Recently, a negative-sense RNA enveloped virus, Apis rhabdovirus-1 (ARV-1), was found in A. mellifera honey bees in Africa, Europe, and islands in the Pacific. Here, we describe the identification - using a metagenomics approach - of ARV-1 in two bee species ( A. mellifera and Bombus impatiens ) and in V. destructor mites from populations collected in the United States and Israel. We confirmed the presence of ARV-1 in pools of A. mellifera , B. impatiens , and V. destructor from Israeli and U.S. populations by RT-PCR and found that it can reach high titers in individual honey bees and mites (10 7 -10 8 viral genomic copies per individual). To estimate the prevalence of ARV-1 in honey bee populations, we screened 104 honey bee colonies across Israel, with 21 testing ARV-1-positive. Tagged-primer-mediated RT-PCR analysis detected the presence of the positive-sense ARV-1 RNA in A. mellifera and V. destructor , indicating that ARV-1 replicates in both hosts. This is the first report of the presence of ARV-1 in B. impatiens and of the replication of a rhabdovirus in A. mellifera and V. destructor . Our data suggest that Varroa mites could act as an ARV-1 vector; however, the presence of ARV-1 in B. impatiens (which are not parasitized by Varroa ) suggests that it may not require the mite for transmission and ARV-1 may be shared among co-foraging bee species. Given that ARV-1 is found in non-Apis bee species, and because "ARV" is used for the Adelaide River virus, we propose that this virus should be called bee rhabdovirus 1 and abbreviated BRV-1. These results

  2. Presence of Apis Rhabdovirus-1 in Populations of Pollinators and Their Parasites from Two Continents

    Directory of Open Access Journals (Sweden)

    Sofia Levin

    2017-12-01

    Full Text Available The viral ecology of bee communities is complex, where viruses are readily shared among co-foraging bee species. Additionally, in honey bees (Apis mellifera, many viruses are transmitted – and their impacts exacerbated – by the parasitic Varroa destructor mite. Thus far, the viruses found to be shared across bee species and transmitted by V. destructor mites are positive-sense single-stranded RNA viruses. Recently, a negative-sense RNA enveloped virus, Apis rhabdovirus-1 (ARV-1, was found in A. mellifera honey bees in Africa, Europe, and islands in the Pacific. Here, we describe the identification – using a metagenomics approach – of ARV-1 in two bee species (A. mellifera and Bombus impatiens and in V. destructor mites from populations collected in the United States and Israel. We confirmed the presence of ARV-1 in pools of A. mellifera, B. impatiens, and V. destructor from Israeli and U.S. populations by RT-PCR and found that it can reach high titers in individual honey bees and mites (107–108 viral genomic copies per individual. To estimate the prevalence of ARV-1 in honey bee populations, we screened 104 honey bee colonies across Israel, with 21 testing ARV-1-positive. Tagged-primer-mediated RT-PCR analysis detected the presence of the positive-sense ARV-1 RNA in A. mellifera and V. destructor, indicating that ARV-1 replicates in both hosts. This is the first report of the presence of ARV-1 in B. impatiens and of the replication of a rhabdovirus in A. mellifera and V. destructor. Our data suggest that Varroa mites could act as an ARV-1 vector; however, the presence of ARV-1 in B. impatiens (which are not parasitized by Varroa suggests that it may not require the mite for transmission and ARV-1 may be shared among co-foraging bee species. Given that ARV-1 is found in non-Apis bee species, and because “ARV” is used for the Adelaide River virus, we propose that this virus should be called bee rhabdovirus 1 and abbreviated BRV-1

  3. Tropilaelaps mite: an emerging threat to European honey bee.

    Science.gov (United States)

    Chantawannakul, Panuwan; Ramsey, Samuel; vanEngelsdorp, Dennis; Khongphinitbunjong, Kitiphong; Phokasem, Patcharin

    2018-04-01

    The risk of transmission of honey bee parasites has increased substantially as a result of trade globalization and technical developments in transportation efficacy. Great concern over honey bee decline has accelerated research on newly emerging bee pests and parasites. These organisms are likely to emerge from Asia as it is the only region where all 10 honey bee species co-occur. Varroa destructor, an ectoparasitic mite, is a classic example of a pest that has shifted from A. cerana, a cavity nesting Asian honey bee to A. mellifera, the European honey bee. In this review, we will describe the potential risks to global apiculture of the global expansion of Tropilaelaps mercedesae, originally a parasite of the open-air nesting Asian giant honey bee, compared to the impact of V. destructor. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Time-course mortality and radiosensitivity indices in Tribolium spp. developing from irradiated pupae

    International Nuclear Information System (INIS)

    Hasan, Md Mahbub

    1999-01-01

    Effects of gamma irradiation (1-5 Krad) on the time-course mortality and radiosensitivity indices in adults of Tribolium anaphe, T. brevicornis, T. castaneum, T. destructor, T. freemani developing from irradiated 1 day old and pre-emergence (4-5 day old) pupae were studied. Adult longevity was significantly (P<0.001) affected by irradiation and was linearly dose dependent. T. destructor was markedly more radioresistant than the other species at all dose levels and had a longer life expectancy. The mean survival times of adults developing from irradiated early and late pupae were shorter in females than in males for all the species. The radiosensitivity indices did not vary widely among the species and these values decreased as the dose increased in all the species which clearly indicate that the resistance of the species was dose-dependent. (author)

  5. Radiation 2006. In association with the Polymer Division, Royal Australian Chemical Institute. Incorporating the 21st AINSE Radiation Chemistry Conference and the 18th Radiation Biology Conference, conference handbook

    International Nuclear Information System (INIS)

    Nugegoda, D.; Blackney, R.; Fuchs, A.; Smith, Suzanne

    2006-01-01

    Full text: The Australian yabby Cherax destructor is tolerant of exposure to many trace metals including Zn and Cd. However it is not known if this tolerance is a result of a low rate of uptake of heavy metals by the yabby, increased excretion, or a combination of both. We now report on the use of radioisotopes of two environmental trace metals 65 Zn and 109 Cd to monitor the uptake by C. destructor of the essential metal Zn and the non-essential metal Cd, at low metal concentrations exposures. Juvenile C. destructor were exposed to three concentrations of Zn with 65 Zn as a tracer for up to 48 hours. Yabbies were sampled at specific time intervals and counted live in tubes with freshwater using a gamma scintillation counter. Water was also sampled and counted at the same time intervals. At the end of the uptake phase, yabbies were dissected into the hepatopancreas, exoskeleton, tail muscle and 'the rest' and each body compartment counted individually. The associated radioactivity was used to calculate the proportional compartmentalization of the trace metals within the body tissues. A similar experiment was repeated with various concentrations of Cd and 109 Cd used to monitor its uptake at various time intervals. Unlike Zn, where its accumulation only plateaued at 72 hour the rate of uptake of Cd reached a plateau after 24 hours. A competitive study was also conducted with the yabbies. Here the yabbies were exposed to similar concentrations of Cd and Zn simultaneously and yabbies were counted to determine Zn and Cd at various intervals. The estimated rates for C. destructor are compared to those of other freshwater crustaceans in order to deduce whether its tolerance to trace metal toxicants is based on reduced rates of uptake

  6. Mating Frequencies of Honey Bee Queens (Apis mellifera L.) in a Population of Feral Colonies in the Northeastern United States

    OpenAIRE

    Tarpy, David R.; Delaney, Deborah A.; Seeley, Thomas D.

    2015-01-01

    Across their introduced range in North America, populations of feral honey bee (Apis mellifera L.) colonies have supposedly declined in recent decades as a result of exotic parasites, most notably the ectoparasitic mite Varroa destructor. Nonetheless, recent studies have documented several wild populations of colonies that have persisted. The extreme polyandry of honey bee queens-and the increased intracolony genetic diversity it confers-has been attributed, in part, to improved disease resis...

  7. Seminario C++, parte 4

    OpenAIRE

    Cachero Castro, Cristina; Ponce de León Amador, Pedro José

    2007-01-01

    Este seminario trata sobre principios de orientación a objetos con C++. Para comprender mejor sus contenidos, se debe tener un conocimiento básico sobre programación estructurada con C++ o C. Herencia simple. El destructor abstracto. Patrón de diseño singleton. Tipos enumerados. Declaraciones forward. Conversión entre objetos (upcasting/downcasting).

  8. An epidemiological model of viral infections in a Varroa-infested bee colony: the case of a bee-dependent mite population size

    OpenAIRE

    Bernardi, Sara; Venturino, Ezio

    2016-01-01

    In recent years the spread of the ectoparasitic mite Varroa destructor has become the most serious threat to worldwide apiculture. In the model presented here we extend the bee population dynamics with mite viral epidemiology examined in an earlier paper by allowing a bee-dependent mite population size. The results of the analysis match field observations well and give a clear explanation of how Varroa affects the epidemiology of certain naturally occurring bee viruses, causing considerable d...

  9. The effect of antibiotics on associated bacterial community of stored product mites.

    Directory of Open Access Journals (Sweden)

    Jan Kopecky

    Full Text Available Bacteria are associated with the gut, fat bodies and reproductive organs of stored product mites (Acari: Astigmata. The mites are pests due to the production of allergens. Addition of antibiotics to diets can help to characterize the association between mites and bacteria.Ampicillin, neomycin and streptomycin were added to the diets of mites and the effects on mite population growth (Acarus siro, Lepidoglyphus destructor and Tyrophagus putrescentiae and associated bacterial community structure were assessed. Mites were treated by antibiotic supplementation (1 mg g(-1 of diet for 21 days and numbers of mites and bacterial communities were analyzed and compared to the untreated control. Bacterial quantities, determined by real-time PCR, significantly decreased in antibiotic treated specimens from 5 to 30 times in A. siro and T. putrescentiae, while no decline was observed in L. destructor. Streptomycin treatment eliminated Bartonella-like bacteria in the both A. siro and T. putrescentiae and Cardinium in T. putrescentiae. Solitalea-like bacteria proportion increased in the communities of neomycin and streptomycin treated A. siro specimens. Kocuria proportion increased in the bacterial communities of ampicillin and streptomycin treated A. siro and neomycin and streptomycin treated L. destructor.The work demonstrated the changes of mite associated bacterial community under antibiotic pressure in pests of medical importance. Pre-treatment of mites by 1 mg g(-1 antibiotic diets improved mite fitness as indicated accelerated population growth of A. siro pretreated streptomycin and neomycin and L. destructor pretreated by neomycin. All tested antibiotics supplemented to diets caused the decrease of mite growth rate in comparison to the control diet.

  10. Selection of VSH-derived “Pol-line” honey bees and evaluation of their Varroa-resistance characteristics

    OpenAIRE

    Danka , Robert G.; Harris , Jeffery W.; Dodds , Garrett E.

    2016-01-01

    International audience; AbstractHoney bees with Varroa sensitive hygiene (VSH) have good resistance to Varroa destructor. We bred “Pol-line” bees by outcrossing VSH queens to US commercial stocks from 2008 to 2014 and then selecting colonies with low mite infestations. Beginning in 2011, field performance of colonies with outcrossed Pol-line queens was compared to colonies with outcrossed VSH queens. Mite infestations after one season were comparable in colonies of the two bee types. Queens f...

  11. Varroa Sensitive Hygiene contributes to naturally selected varroa resistance in honey bees

    OpenAIRE

    Panziera, Delphine; Langevelde, van, Frank; Blacquière, Tjeerd

    2017-01-01

    The parasitic mite Varroa destructor is a serious threat for western honey bee colonies and beekeepers are compelled to control it to keep their colonies healthy. Yet, by controlling varroa no resistance to the parasite can evolve. As a trial, honey bee colonies have been left untreated in isolated locations to allow development of resistance or tolerance to the mite. These colonies developed an ability to live without control measures against varroa, although the traits responsible for this ...

  12. High-Resolution Linkage Analyses to Identify Genes That Influence Varroa Sensitive Hygiene Behavior in Honey Bees

    OpenAIRE

    Tsuruda, Jennifer M.; Harris, Jeffrey W.; Bourgeois, Lanie; Danka, Robert G.; Hunt, Greg J.

    2012-01-01

    Varroa mites (V. destructor) are a major threat to honey bees (Apis melilfera) and beekeeping worldwide and likely lead to colony decline if colonies are not treated. Most treatments involve chemical control of the mites; however, Varroa has evolved resistance to many of these miticides, leaving beekeepers with a limited number of alternatives. A non-chemical control method is highly desirable for numerous reasons including lack of chemical residues and decreased likelihood of resistance. Var...

  13. Antennae hold a key to Varroa-sensitive hygiene behaviour in honey bees

    OpenAIRE

    Mondet, Fanny; Alaux, C?dric; Severac, Dany; Rohmer, Marine; Mercer, Alison R.; Le Conte, Yves

    2015-01-01

    In honey bees, Varroa sensitive hygiene (VSH) behaviour, which involves the detection and removal of brood parasitised by the mite Varroa destructor, can actively participate in the survival of colonies facing Varroa outbreaks. This study investigated the mechanisms of VSH behaviour, by comparing the antennal transcriptomes of bees that do and do not perform VSH behaviour. Results indicate that antennae likely play a key role in the expression of VSH behaviour. Comparisons with the antennal t...

  14. Apiculture and Bee Health in Central Sweden

    OpenAIRE

    Larne, Olof

    2014-01-01

    Pollination necessary for the agricultural crop production affects the functions of the ecosystems on earth. In landscapes where wild pollinators are decreasing, honey bees promote the maintenance of plant species, therefore honey bee losses are of great concern. Current honey bee colony losses (Apis mellifera) worldwide are caused by Colony collapse disorder, the mite Varroa destructor and pesticides. This results in the honey bees weakened immune defenses making them susceptible to differen...

  15. The effect of pathogens and pests on honey bee gene expression

    OpenAIRE

    Navajas Navarro, Maria; Martin, Jean-François; Le Conte, Yves; Queen's University Belfast

    2008-01-01

    The effect of pathogens and pests on honey bee gene expression is a fascinating area of research in itself and can lead to new molecular tools for diagnostics and selection in beekeeping. In this framework, we first investigated Varroa-bee interactions by using a combination of nuc1ear and mitochondrial DNA markers of Varroa destructor to trace the parasite invasion of Apis mellifera since it shifted from A. cerana. The extremely low worldwide mite genetic diversity found on A. ...

  16. Resistance to Wheat Curl Mite in Arthropod-Resistant Rye-Wheat Translocation Lines

    Directory of Open Access Journals (Sweden)

    Lina Maria Aguirre-Rojas

    2017-11-01

    Full Text Available The wheat curl mite, Aceria toschiella (Keifer, and a complex of viruses vectored by A. toschiella substantially reduce wheat yields in every wheat-producing continent in the world. The development of A. toschiella-resistant wheat cultivars is a proven economically and ecologically viable method of controlling this pest. This study assessed A. toschiella resistance in wheat genotypes containing the H13, H21, H25, H26, H18 and Hdic genes for resistance to the Hessian fly, Mayetiola destructor (Say and in 94M370 wheat, which contains the Dn7 gene for resistance to the Russian wheat aphid, Diuraphis noxia (Kurdjumov. A. toschiella populations produced on plants containing Dn7 and H21 were significantly lower than those on plants of the susceptible control and no different than those on the resistant control. Dn7 resistance to D. noxia and H21 resistance to M. destructor resulted from translocations of chromatin from rye into wheat (H21—2BS/2RL, Dn7—1BL/1RS. These results provide new wheat pest management information, indicating that Dn7 and H21 constitute resources that can be used to reduce yield losses caused by A. toschiella, M. destructor, D. noxia, and wheat streak mosaic virus infection by transferring multi-pest resistance to single sources of germplasm.

  17. Plant-Derived Tick Repellents Activate the Honey Bee Ectoparasitic Mite TRPA1

    Directory of Open Access Journals (Sweden)

    Guangda Peng

    2015-07-01

    Full Text Available We have identified and characterized the TRPA1 channel of Varroa destructor (VdTRPA1, a major ectoparasitic mite of honey bee. One of the two VdTRPA1 isoforms, VdTRPA1L, was activated by a variety of plant-derived compounds, including electrophilic compounds, suggesting that chemical activation profiles are mostly shared between arthropod TRPA1 channels. Nevertheless, carvacrol and α-terpineol activated VdTRPA1L but not a honey bee noxious-stimuli-sensitive TRPA, AmHsTRPA, and Drosophila melanogaster TRPA1. Activation of VdTRPA1L in D. melanogaster taste neurons by the above compounds was sufficient to modify the gustatory behaviors. Carvacrol and α-terpineol repelled V. destructor in a laboratory assay, and α-terpineol repressed V. destructor entry for reproduction into the brood cells in hives. Understanding the functions of parasite TRP channels not only gives clues about the evolving molecular and cellular mechanisms of parasitism but also helps in the development of control methods.

  18. Assessing hygienic behavior of Apis mellifera unicolor (Hymenoptera: Apidae), the endemic honey bee from Madagascar.

    Science.gov (United States)

    Rasolofoarivao, H; Delatte, H; Raveloson Ravaomanarivo, L H; Reynaud, B; Clémencet, J

    2015-06-01

    Hygienic behavior (HB) is one of the natural mechanisms of honey bee for limiting the spread of brood diseases and Varroa destructor parasitic mite. Objective of our study was to measure HB of Apis mellifera unicolor colonies (N = 403) from three geographic regions (one infested and two free of V. destructor) in Madagascar. The pin-killing method was used for evaluation of the HB. Responses were measured from 3 h 30 min to 7 h after perforation of the cells. Colonies were very effective in detecting perforated cells. In the first 4 h, on average, they detected at least 50% of the pin-killed brood. Six hours after cell perforation, colonies tested (N = 91) showed a wide range of uncapped (0 to 100%) and cleaned cells (0 to 82%). Global distribution of the rate of cleaned cells at 6 h was multimodal and hygienic responses could be split in three classes. Colonies from the three regions showed a significant difference in HB responses. Three hypotheses (geographic, genetic traits, presence of V. destructor) are further discussed to explain variability of HB responses among the regions. Levels of HB efficiency of A. mellifera unicolor colonies are among the greatest levels reported for A. mellifera subspecies. Presence of highly hygienic colonies is a great opportunity for future breeding program in selection for HB.

  19. TENSOR DECOMPOSITIONS AND SPARSE LOG-LINEAR MODELS

    Science.gov (United States)

    Johndrow, James E.; Bhattacharya, Anirban; Dunson, David B.

    2017-01-01

    Contingency table analysis routinely relies on log-linear models, with latent structure analysis providing a common alternative. Latent structure models lead to a reduced rank tensor factorization of the probability mass function for multivariate categorical data, while log-linear models achieve dimensionality reduction through sparsity. Little is known about the relationship between these notions of dimensionality reduction in the two paradigms. We derive several results relating the support of a log-linear model to nonnegative ranks of the associated probability tensor. Motivated by these findings, we propose a new collapsed Tucker class of tensor decompositions, which bridge existing PARAFAC and Tucker decompositions, providing a more flexible framework for parsimoniously characterizing multivariate categorical data. Taking a Bayesian approach to inference, we illustrate empirical advantages of the new decompositions. PMID:29332971

  20. Radiation from a hot, thin plasma from 1 to 250 A

    International Nuclear Information System (INIS)

    Kato, T.

    1976-01-01

    A calculation of emission spectrum of a hot, low-density plasma in the region 1--250 A is presented. The mechanisms considered are electron collision-induced line emission, bremsstrahlung, and radiative recombination; and the temperature range studied is 10 5 --10 7 K. 795 lines are included. The elemental abundances of the ions of He, C, N, O, Ne, Mg, Si, S, Ca, Fe, and Ni were taken to be as in the solar corona. The line emission of Fe ions produces a maximum in the curve of an emission power between 1 and 250 A versus temperature around 10 6 K. The emission rate around 10 6 K is larger than the results calculated by Cox and Tucker and Tucker and Koren

  1. Production and characterization of antifungal compounds produced by Lactobacillus plantarum IMAU10014.

    Directory of Open Access Journals (Sweden)

    HaiKuan Wang

    Full Text Available Lactobacillus plantarum IMAU10014 was isolated from koumiss that produces a broad spectrum of antifungal compounds, all of which were active against plant pathogenic fungi in an agar plate assay. Two major antifungal compounds were extracted from the cell-free supernatant broth of L. plantarum IMAU10014. 3-phenyllactic acid and Benzeneacetic acid, 2-propenyl ester were carried out by HPLC, LC-MS, GC-MS, NMR analysis. It is the first report that lactic acid bacteria produce antifungal Benzeneacetic acid, 2-propenyl ester. Of these, the antifungal products also have a broad spectrum of antifungal activity, namely against Botrytis cinerea, Glomerella cingulate, Phytophthora drechsleri Tucker, Penicillium citrinum, Penicillium digitatum and Fusarium oxysporum, which was identified by the overlay and well-diffusion assay. F. oxysporum, P. citrinum and P. drechsleri Tucker were the most sensitive among molds.

  2. Tensor decompositions for the analysis of atomic resolution electron energy loss spectra

    Energy Technology Data Exchange (ETDEWEB)

    Spiegelberg, Jakob; Rusz, Ján [Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala (Sweden); Pelckmans, Kristiaan [Department of Information Technology, Uppsala University, Box 337, S-751 05 Uppsala (Sweden)

    2017-04-15

    A selection of tensor decomposition techniques is presented for the detection of weak signals in electron energy loss spectroscopy (EELS) data. The focus of the analysis lies on the correct representation of the simulated spatial structure. An analysis scheme for EEL spectra combining two-dimensional and n-way decomposition methods is proposed. In particular, the performance of robust principal component analysis (ROBPCA), Tucker Decompositions using orthogonality constraints (Multilinear Singular Value Decomposition (MLSVD)) and Tucker decomposition without imposed constraints, canonical polyadic decomposition (CPD) and block term decompositions (BTD) on synthetic as well as experimental data is examined. - Highlights: • A scheme for compression and analysis of EELS or EDX data is proposed. • Several tensor decomposition techniques are presented for BSS on hyperspectral data. • Robust PCA and MLSVD are discussed for denoising of raw data.

  3. Kaitstud magistri- ja doktoritööd 2011

    Index Scriptorium Estoniae

    2012-01-01

    TÜ-s kaitsesid magistritööd Lauri Linask, Liisi Rünkla, Anna Mossolova, Pärt Ojamaa, Nelly Mäekivi, Rasmus Pedanik, Carlos Andres Hernandez Perez, Burhan Sayili, Aune Ainson, Arlene Tucker, Remo Gramigna, Kristin Orav, Svitlana Biedarieva, Alejandra Pineda Silva, Maximino Matus Ruiz, Cesar Octavio Moreno Zayas, Mara Cay Woods, Taras Boyko; doktoritööd Kati Lindström ja Morten Tønnessen

  4. A CLASS OF NONMONOTONE TRUST REGION ALGORITHMS FOR LINEARLY CONSTRAINED OPTIMIZATION%线性约束优化的一类非单调信赖域算法

    Institute of Scientific and Technical Information of China (English)

    葛恒武; 陈中文

    2002-01-01

    We present a class of nonmonotone trust region algorithms for linearly constrained optimization in this paper.The algorithm may adjust automatically the scope of the monotonicity by the degree that the quadratic model is "trusted".Under the suitable conditions,it is proved that any limit point of the infinite sequence generated by the algorithm is the Kuhn-Tucker point of the primal problem.Finally,some numerical results show that the new algorithm is very effective.

  5. On Equivalence between Optimality Criteria and Projected Gradient Methods with Application to Topology Optimization Problem

    OpenAIRE

    Ananiev, Sergey

    2006-01-01

    The paper demonstrates the equivalence between the optimality criteria (OC) method, initially proposed by Bendsoe & Kikuchi for topology optimization problem, and the projected gradient method. The equivalence is shown using Hestenes definition of Lagrange multipliers. Based on this development, an alternative formulation of the Karush-Kuhn-Tucker (KKT) condition is suggested. Such reformulation has some advantages, which will be also discussed in the paper. For verification purposes the modi...

  6. Selection of Air Traffic Controllers,

    Science.gov (United States)

    1984-08-01

    Institute of Bahavioral Research, Texas Christian University Joseph A. Tucker, Ph.D. Professor of Instructional Technology, The Catholic University of...Peace Corps volunteers (Gordon, 1967); nursing students in their first year of training (Katzell, 1968); nursing turn- over in a teaching hospital (Saleh...retired FAA controllers and instructors who volunteered to help in the crisis. A student’s first few days (Phase I) at the Academy are spent in per

  7. Organizing for Irregular Warfare: Implications for the Brigade Combat Team

    Science.gov (United States)

    2007-12-01

    program on October 13, 2006. For further information see, Stew Magnuson, “Eyes Wide Open,” National Defense May 2007, 46. 227 John A. English...David Tucker and Christopher J. Lamb , “Restructuring Special Operations Forces for Emerging Threats,” Strategic Forum no. 219 (January 2006) to... Stew . “Eyes Wide Open.” National Defense, May 2007. Malcom, Ben S. White Tigers, My Secret War in Korea. U.S.: Brassey’s, 2003

  8. A Hierarchical Dispatch Structure for Distribution Network Pricing

    OpenAIRE

    Yuan, Zhao; Hesamzadeh, Mohammad Reza

    2015-01-01

    This paper presents a hierarchical dispatch structure for efficient distribution network pricing. The dispatch coordination problem in the context of hierarchical network operators are addressed. We formulate decentralized generation dispatch into a bilevel optimization problem in which main network operator and the connected distribution network operator optimize their costs in two levels. By using Karush-Kuhn-Tucker conditions and Fortuny-Amat McCarl linearization, the bilevel optimization ...

  9. Semi Quantitative MALDI TOF for Antimicrobial Susceptibility Testing in Staphylococcus aureus

    Science.gov (United States)

    2017-08-31

    Semi- quantitative MALDI-TOF for antimicrobial susceptibility testing in Staphylococcus 1 aureus 2 3 4 Tucker Maxson,a Cheryl L. Taylor-Howell,a...Timothy D. Minoguea# 5 6 Diagnostic Systems Division, United States Army Medical Research Institute of Infectious 7 Disease, Fort Detrick, MD...USAa 8 9 Running Title: Quantitative MALDI for AST in S. aureus 10 #Address correspondence to Timothy D. Minogue, timothy.d.minogue.civ@mail.mil

  10. Economics of Forest Fire Management: Spatial Accounting of Costs and Benefits

    OpenAIRE

    Sanchez, Jose Julio

    2014-01-01

    A nonmarket valuation approach is used in this study to evaluate the recreation values of the San Jacinto Wilderness in southern California. The analysis utilizes survey data from a stated-choice experiment involving backcountry visitors who responded to questions about hypothetical wildfire burn scenarios. Benefits of landscape preservation are derived using a Kuhn-Tucker (KT) demand system. Model results suggest that recreationists are more attracted to sites with recent foreground wildf...

  11. Efficient Matrix Models for Relational Learning

    Science.gov (United States)

    2009-10-01

    base learners and h1:r is the ensemble learner. For example, consider the case where h1, . . . , hr are linear discriminants. The weighted vote of...a multilinear form naturally leads one to consider tensor factorization: e.g., UAV T is a special case of Tucker decomposition [129] on a 2D- tensor , a...matrix. Our five modeling choices can also be used to differentiate tensor factorizations, but the choices may be subtler for tensors than for

  12. Effects of global change on tropical ecosystems

    CSIR Research Space (South Africa)

    Scholes, RJ

    1997-09-01

    Full Text Available composition and climate. Although the combustion of fossil fuels is the dominant source of the observed increase in the atmospheric carbon dioxide (CO,) content at the present time (Watson et al., 19921, the release of CO... forest or bush is even more poorly documented than the original clearing (Skole and Tucker, 1993; Skole et al., 1994). There is a continuous switching between agricultural production systems, driven by local social, economic...

  13. Intelligence Operations In Small Wars: A Comparison Of The Malayan Emergency And Vietnam War

    Science.gov (United States)

    2013-04-01

    Effect, 18. 41 Spencer C. Tucker, David Coffey, Nguyen Cong Luan, Nike Nichols, and Sandra Wittman, eds, Encyclopedia of the Vietnam War Volume One: A...War: The Unexamined Victories and Final Tragedy of America’s Last Years in Vietnam, (Orlando, FL :Harcourt, Inc ., 1999), 72-73. 91 Sorley, A Better...Victories and Final Tragedy of America’s Last Years in Vietnam. Orlando, FL: Harcourt, Inc ., 1999. Stubbs, Richard. Hearts and Minds in

  14. Perception by Operators of Approach and Withdrawal of Moving Sound Sources

    Science.gov (United States)

    1999-01-01

    Tucker, 1988; Strybel and Neal, 1994) or between stationary and moving sound sources or auditory images (Perrott and Musikant , 1977; Strybel and Neale...conditions of stimulation (Viskov, 1975; Perrott and Musikant , 1977; Strybel et al., 1989; Sabery and Perrott, 1990; Strybel et al., 1992; Strybel and...noise and its relation to masking and loudness// JASA, 1947. V.19. P. 609-619. 24. Perrott D.R., Musicant A.D. Minimum auditory movement angle: binaural

  15. Analysis and Modeling of Complex Geomorphic Systems: Technique Development, Data Collection, and Application to Rangeland Terrain

    Science.gov (United States)

    2008-10-01

    Tucker, GE, Arnold, L, and Stokes, S (2004) Evidence for autogenic cyclicity in ephemeral stream cut-fill deposits. Paper presented at American...of management activity (such as mechanized training ). However, there are a number of important knowledge gaps regarding how such landscapes re- spond...the Fort Carson military reservation, the Pinon Canyon Maneuver Site (PCMS, a training area in southeastern Colorado adminis- tered by Fort Carson

  16. Potential for Mosquitoes (Diptera: Culicidae) From Florida to Transmit Rift Valley Fever Virus

    Science.gov (United States)

    2013-09-01

    signiÞcant disease and economic disruption. Rift Valley fever virus (RVFV), whichhasbeen responsible fornumerousoutbreaksof severe disease in ruminants and...is predominately a disease of domestic ruminants (cattle, goats, and sheep), where infection in pregnant animals usually results in abortion, and...www.cdc.gov/EID/ content /13/8/e1.htm). Britch, S.C.,K. J.Linthicum,A.Anyamba,C. J.Tucker,E.W. Pak, F. A. Maloney, K. Cobb, E. Stanwix, J. Humphries, A

  17. Social Resources That Preserve Functional Independence After Memory Loss

    Science.gov (United States)

    2016-07-01

    Toward a common language for function, disability, and health. Physical therapy 86, 726 (May, 2006). 4. R. D. Tucker-Seeley, S. V. Subramanian, Y...20. Boyle PA, Buchman AS, Wilson RS, et al: Physical activity is asso- ciated with incident disability in community-based older persons. J Am Geriatr ...effects of physical activity on physical functioning, quality of life and depression in older people with dementia. Int J Geriatr Psychiatry. 2011

  18. Constrained Optimization via Stochastic approximation with a simultaneous perturbation gradient approximation

    DEFF Research Database (Denmark)

    Sadegh, Payman

    1997-01-01

    This paper deals with a projection algorithm for stochastic approximation using simultaneous perturbation gradient approximation for optimization under inequality constraints where no direct gradient of the loss function is available and the inequality constraints are given as explicit functions...... of the optimization parameters. It is shown that, under application of the projection algorithm, the parameter iterate converges almost surely to a Kuhn-Tucker point, The procedure is illustrated by a numerical example, (C) 1997 Elsevier Science Ltd....

  19. Review of Terrence Malick: Film and Philosophy

    Directory of Open Access Journals (Sweden)

    Emre Çağlayan

    2014-10-01

    Full Text Available This new anthology edited by Thomas Dean Tucker and Stuart Kendall predates the release of The Tree of Life and examines Malick’s earlier work from a variety of philosophical perspectives. The editors argue that Malick’s background in philosophy not only warrants philosophical questions into his oeuvre, but more importantly his “films offer privileged sites for this kind of inquiry”

  20. In Contact! Case Studies from the Long War. Volume I

    Science.gov (United States)

    2006-01-01

    lull, Bellavia called his platoon sergeant, Cantrell, on his radio. Cantrell, who was not with Meno, immediately responded yelling into the mike ...at <http://www.infoplease.com/ipa/A0107644.html>, accessed 12 June 2006. 3. Mike Tucker, Among Warriors in Iraq: True Grit, Special Ops, and...SGT Kennedy SPC Detman SPC Hubbard SPC Graff SPC Harris SPC Rullo SPC Kinzer SPC Sharples SPC Heesacker SPC Birkel SPC Schrad Regulator 3 SSG Castro SPC

  1. Engineering Evaluation and Analysis for the Improvement of Military Standard Generators. Volume 1.

    Science.gov (United States)

    1987-05-29

    Heights, MI 48077 Schenectady, NY 12301-1058 (32) Peter Diesels, Inc. (44) Snyder Industries, Inc. 4761 Hugh Howell Road 4700 FreemontTucker, GA 30084 Box...Aaisi-icns 7 ;s:ems Marazeen: :e 1 an 30 k. o -. -e e aco se i o’*.: -- c-.weerA Ica i 1 -re 7h3. ~e .1arv e:mres zec an :nrterast to r-asoive -.e

  2. Multiway analysis methods applied to the fluorescence excitation-emission dataset for the simultaneous quantification of valsartan and amlodipine in tablets

    Science.gov (United States)

    Dinç, Erdal; Ertekin, Zehra Ceren; Büker, Eda

    2017-09-01

    In this study, excitation-emission matrix datasets, which have strong overlapping bands, were processed by using four different chemometric calibration algorithms consisting of parallel factor analysis, Tucker3, three-way partial least squares and unfolded partial least squares for the simultaneous quantitative estimation of valsartan and amlodipine besylate in tablets. In analyses, preliminary separation step was not used before the application of parallel factor analysis Tucker3, three-way partial least squares and unfolded partial least squares approaches for the analysis of the related drug substances in samples. Three-way excitation-emission matrix data array was obtained by concatenating excitation-emission matrices of the calibration set, validation set, and commercial tablet samples. The excitation-emission matrix data array was used to get parallel factor analysis, Tucker3, three-way partial least squares and unfolded partial least squares calibrations and to predict the amounts of valsartan and amlodipine besylate in samples. For all the methods, calibration and prediction of valsartan and amlodipine besylate were performed in the working concentration ranges of 0.25-4.50 μg/mL. The validity and the performance of all the proposed methods were checked by using the validation parameters. From the analysis results, it was concluded that the described two-way and three-way algorithmic methods were very useful for the simultaneous quantitative resolution and routine analysis of the related drug substances in marketed samples.

  3. Application of multi-way analysis to UV-visible spectroscopy, gas chromatography and electronic nose data for wine ageing evaluation.

    Science.gov (United States)

    Prieto, N; Rodriguez-Méndez, M L; Leardi, R; Oliveri, P; Hernando-Esquisabel, D; Iñiguez-Crespo, M; de Saja, J A

    2012-03-16

    In this study, a multi-way method (Tucker3) was applied to evaluate the performance of an electronic nose for following the ageing of red wines. The odour evaluation carried out with the electronic nose was combined with the quantitative analysis of volatile composition performed by GC-MS, and colour characterisation by UV-visible spectroscopy. Thanks to Tucker3, it was possible to understand connections among data obtained from these three different systems and to estimate the effect of different sources of variability on wine evaluation. In particular, the application of Tucker3 supplied a global visualisation of data structure, which was very informative to understand relationships between sensors responses and chemical composition of wines. The results obtained indicate that the analytical methods employed are useful tools to follow the wine ageing process, to differentiate wine samples according to ageing type (either in barrel or in stainless steel tanks with the addition of small oak wood pieces) and to the origin (French or American) of the oak wood. Finally, it was possible to designate the volatile compounds which play a major role in such a characterisation. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Tensor decomposition in electronic structure calculations on 3D Cartesian grids

    International Nuclear Information System (INIS)

    Khoromskij, B.N.; Khoromskaia, V.; Chinnamsetty, S.R.; Flad, H.-J.

    2009-01-01

    In this paper, we investigate a novel approach based on the combination of Tucker-type and canonical tensor decomposition techniques for the efficient numerical approximation of functions and operators in electronic structure calculations. In particular, we study applicability of tensor approximations for the numerical solution of Hartree-Fock and Kohn-Sham equations on 3D Cartesian grids. We show that the orthogonal Tucker-type tensor approximation of electron density and Hartree potential of simple molecules leads to low tensor rank representations. This enables an efficient tensor-product convolution scheme for the computation of the Hartree potential using a collocation-type approximation via piecewise constant basis functions on a uniform nxnxn grid. Combined with the Richardson extrapolation, our approach exhibits O(h 3 ) convergence in the grid-size h=O(n -1 ). Moreover, this requires O(3rn+r 3 ) storage, where r denotes the Tucker rank of the electron density with r=O(logn), almost uniformly in n. For example, calculations of the Coulomb matrix and the Hartree-Fock energy for the CH 4 molecule, with a pseudopotential on the C atom, achieved accuracies of the order of 10 -6 hartree with a grid-size n of several hundreds. Since the tensor-product convolution in 3D is performed via 1D convolution transforms, our scheme markedly outperforms the 3D-FFT in both the computing time and storage requirements.

  5. Evidence in support of the call to ban the tackle and harmful contact in school rugby: a response to World Rugby.

    Science.gov (United States)

    Pollock, Allyson M; White, Adam John; Kirkwood, Graham

    2017-08-01

    In a paper published in BJSM (June 2016), World Rugby employees Ross Tucker and Martin Raftery and a third coauthor Evert Verhagen took issue with the recent call to ban tackling in school rugby in the UK and Ireland. That call (to ban tackling) was supported by a systematic review published in BJSM Tucker et al claim that: (1) the mechanisms and risk factors for injury along with the incidence and severity of injury in youth rugby union have not been thoroughly identified or understood; (2) rugby players are at no greater risk of injury than other sports people, (3) this is particularly the case for children under 15 years and (4) removing the opportunity to learn the tackle from school pupils might increase rates of injuries. They conclude that a ban 'may be unnecessary and may also lead to unintended consequences such as an increase in the risk of injury later in participation.' Here we aim to rebut the case by Tucker et al We share new research that extends the findings of our original systematic review and meta-analysis. A cautionary approach requires the removal of the tackle from school rugby as the quickest and most effective method of reducing high injury rates in youth rugby, a public health priority. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  6. INCIDENCIA Y NIVEL DE INFESTACIÓN POR VARROASIS EN ABEJAS (Apis mellifera EN EL LABORATORIO DE IDENTIFICACIÓN Y DIAGNÓSTICO APÍCOLA DE 2002 A 2006

    Directory of Open Access Journals (Sweden)

    Agustín Ruíz-Flores

    2012-01-01

    Full Text Available El objetivo fue estudiar las tendencias anuales y mensuales para el número de muestras positivas (NMP y el nivel de infestación (NI por Varroa destructor en abejas (Apis mellifera. El estudio se realizó de 2002 a 2006 en el Laboratorio de Identificación y Diagnóstico Apícola de la SAGARPA. La detección del ácaro se realizó con la técnica de De Jong para V. destructor. Los estimadores de las tendencias anuales y mensuales para NMP y NI se obtuvieron mediante regresión. El promedio mensual para NMP fue 47.6 ± 49.3 (0 a 248 muestras. La tendencia anual para el incremento del NMP fue -5.69 ± 4.48 (P = 0.2087. La tendencia mensual de enero a diciembre fue 0.91 ± 1.7 (P = 0.6024. El NI promedio fue 3.27 ± 2.6 %, el promedio mensual varió de 0 a 10.06 %. La tasa media de incremento anual en el NI fue 0.34 ± 0.23 % (P = 0.2494. La tasa media de incremento mensual de enero a diciembre fue -0.17 ± 0.1 % (P = 0.1194. Los NMP con V. destructor y los NI, no mostraron incrementos significativos para el periodo estudiado. No se detectó el efecto de la estacionalidad sobre el NMP y NI.

  7. Risk factors for the presence of Deformed wing virus and Acute bee paralysis virus under temperate and subtropical climate in Argentinian bee colonies.

    Science.gov (United States)

    Molineri, Ana; Giacobino, Agostina; Pacini, Adriana; Bulacio Cagnolo, Natalia; Fondevila, Norberto; Ferrufino, Cecilia; Merke, Julieta; Orellano, Emanuel; Bertozzi, Ezequiel; Masciángelo, Germán; Pietronave, Hernán; Signorini, Marcelo

    2017-05-01

    Beekeepers all across the world are suffering important losses of their colonies, and the parasitic mites Varroa destructor and Nosema sp, as well as several bee viruses, are being pointed out as the possible causes of these losses, generally associated with environmental and management factors. The objective of the present study was to evaluate the presence of seven virus species (Deformed wing virus -DWV-, Acute bee paralysis virus -ABPV-, Chronic bee paralysis virus -CBPV-, Black queen cell virus -BQCV-, Kashmir bee virus -KBV-, Israeli acute bee paralysis virus -IAPV-, and Sacbrood bee virus -SBV), as well as the prevalence of Nosema sp. and Varroa destructor, and their possible associated factors, under temperate and subtropical climate conditions in Argentinean colonies. A total of 385 colonies distributed in five Argentinean eco-regions were examined after honey harvest. The final multivariable model revealed only one variable associated with the presence of DWV and two with the presence of ABPV. The apiary random effect was significant in both cases (P=0.018; P=0.006, respectively). Colonies with a Varroa infestation rate >3% showed higher presence of DWV than colonies with <3% of Varroa infestation level (OR=1.91; 95% CI: 1.02-3.57; P<0.044). The same pattern was observed for the presence of ABPV (OR=2.23; 95% CI: 1.04-4.77; P<0.039). Also, colonies where replacement of old combs was not a common practice had higher presence of ABPV (OR=6.02; 95% CI: 1.16-31.25; P<0.033). Regardless of the location of the colonies, virus presence was strongly associated with V. destructor level. Therefore, all the factors that directly or indirectly influence the levels of mites will be also influencing the presence of the viruses. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Investigation of PCBs biodegradation by soil bacteria using tritium-labeled PCBs

    International Nuclear Information System (INIS)

    Kim, A.A.; Djuraeva, G.T.; Takhtobin, K.S.; Kadirova, M.; Yadgarov, H.T.; Zinovev, P.V.; Abdukarimov, A.A.

    2004-01-01

    The method of tritium labeling of polychlorinated biphenyls (PCBs) has been developed. It allows producing of uniformly labeled tritium PCBs. High specific activity permits the tracing all of the tritium labeled PCBs biodegradation products. Radiochemical approach of the investigation of PCBs microbial degradation has been developed and PCB-destructive activity of soil bacteria strains has been studied. It was found that 4 investigated bacteria strains of Bacillus sp. has the ability accumulate and destroy PCBs. Use of developed radiochemical methods in complex with other analytical methods in investigation of PCBs biodegradation provide useful additional information. The radiochemical methods developed can be successfully used for wide screening of microorganisms, destructors of PCBs. (author)

  9. Tratamentos alternativos no combate à Varroa. Aplicação na apicultura biológica em Trás-os-Montes e Alto Douro

    OpenAIRE

    Vilas-Boas, Miguel

    2004-01-01

    A varroose é urna doença parasitária externa das abelhas causada por um ácaro denominado por Varroa destructor. Este parasita original mente presente nas abelhas melíferas asiáticas Apis cerana, onde coexiste numa relação simbiótica parasita/hospedeiro,foi detectado pela primeira vez em 1963 em colónias de abelhas Appis mellífera. Este salto imediato não Ihes permitiu criar os seus mecanismos de resistência ao parasita, pelo que se verifica actualmente urna mortalidade eleva...

  10. Perdas de colônias de Apis mellifera L. no inverno suplementadas com alimentação artificial com pólen e favos de mel

    Directory of Open Access Journals (Sweden)

    Adhemar Pegoraro

    2012-11-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito do tipo de suplementação, nas áreas de cria, alimento e infestação por Varroa destructor nas colônias perdidas. Foram analisadas18 colônias de Apis mellifera L. alojadas em colméias modelo Langstroth e submetidas a dois tipos de suplementação alimentar: 1- cremosa (açúcar cristal moído, mel e pólen; 2- favos de mel. As áreas de ovo-larva e pupa, néctar, mel e pólen das 18 colônias foram fotografadas e analisadas com o auxílio do software AutoCAD. As colônias perdidas suplementadas com alimento artificial e pólen possuíam áreas de: ovo-larva (87,79 ± 70,38cm2, pupa (228,46 ± 192,94cm2, néctar (1.219 ± 149,58cm2, mel (563,47 ± 807,93cm2, pólen (139,09 ± 80,30cm2 e percentagem de infestação por V. destructor (10,50 ± 4,30%. As colônias perdidas suplementadas com favos de mel possuíam áreas de ovo-larva (7,92 ± 9,35cm2, pupas (60,71 ± 63,94 cm2, néctar (658,22 ± 1.040,94cm2, mel (122,62 ± 49,45cm2, pólen (53,58 ± 72,39cm2 e percentagem de infestação por V. destructor (14,40 ± 1,56%. As causas das perdas em parte podem ser atribuídas à infestação por V. destructor.

  11. A Comparative Study of Environmental Conditions, Bee Management and the Epidemiological Situation in Apiaries Varying in the Level of Colony Losses

    Directory of Open Access Journals (Sweden)

    Pohorecka Krystyna

    2014-12-01

    Full Text Available Explaining the reasons for the increased mortality of the honey bee (Apis mellifera L. in recent years, in Europe and North America, has become a global research priority in apicultural science. Our project was aimed at determining the relationship between environmental conditions, beekeeping techniques, the epidemiological situation of pathogens, and the mortality rate of bee colonies. Dead bee samples were collected by beekeepers from 2421 colonies. The samples were examined for the presence of V. destructor, Nosema spp. (Nosema apis and Nosema ceranae, chronic bee paralysis virus (CBPV, acute bee paralysis virus (ABPV, deformed wing virus (DWV, and Israeli acute paralysis virus (IAPV.

  12. Uso de HeberPAG en carcinoma basocelular periocular

    Directory of Open Access Journals (Sweden)

    Yanisel Jiménez Barbán

    Full Text Available Se describe el caso clínico de un paciente de 34 años de edad con un carcinoma basocelular nodular de párpado inferior del ojo izquierdo, de 3 años de evolución. Se procedió a aplicar el HeberPAG en inyección perilesional 3 veces por semana durante 3 semanas consecutivas. Terminadas las aplicaciones de este producto desaparecieron los signos clínicos del tumor. Se comenta el potencial destructor de este tumor, así como las técnicas utilizadas en el manejo de esta patología.

  13. Ensaio sobre a eficácia do ácido fórmico no tratamento da Varroose

    OpenAIRE

    Pires, Sância; Serrano, José; Ruíz, José; Pereira, Óscar; Silva, Elisa

    2004-01-01

    Este ensaio teve como objectivo estudar a eficácia do ácido fórmico no tratamento da Varroose. O ensaio decorreu num apiário situado na área de influência do Parque Natural de Montesinho. De acordo com a metodologia descrita por (2; 3), em 15 colmeias de modelo Langstroth e infestadas de forma natural, pelo ácaro Varroa destructor (1), aplicámos esponjas impregnadas com 240 mi de ácido fórmico a 85%, durante 20 dias.

  14. Inventaire préliminaire des ravageurs et des ennemis naturels du cotonnier du département de l'Ouémé (République du Bénin

    Directory of Open Access Journals (Sweden)

    Tchibozo, S.

    1995-01-01

    Full Text Available Preliminary Inventory of Pests and Natural Enemies on Cotton in Oueme Department, Benin. The cotton plant is attacked by thousand of insects pests whose natural enemies are not well known in some producing countries. In order to make an inventory of pests and natural enemies, a first work has been realized on cotton entomological fauna in Oueme Department during agricultural campaign 1993-1994. The results obtained, allowed us to list ail the pests, and their natural enemies met on cotton per locality. The main destructors are classified according to their relative importance. For each pest the frequency of natural enemies is assessed.

  15. Small-cell comb does not control Varroa mites in colonies of honeybees of European origin

    OpenAIRE

    Seeley , Thomas; Griffin , Sean

    2011-01-01

    International audience; We tested the idea that Varroa destructor can be controlled in colonies of the European subspecies of Apis mellifera by providing them with combs built of small cells, in which immature mites might have difficulty developing for lack of space. We established seven pairs of equal-size colonies that started out equally infested with mites. In each pair, one hive contained only standard-cell (5.4 mm) comb, and the other contained only small-cell (4.8 mm) comb. We measured...

  16. Detection of chronic bee paralysis virus and acute bee paralysis virus in Uruguayan honeybees.

    Science.gov (United States)

    Antúnez, Karina; D' Alessandro, Bruno; Corbella, Eduardo; Zunino, Pablo

    2005-09-01

    Chronic bee paralysis virus (CBPV) causes a disease characterized by trembling, flightless, and crawling bees, while Acute bee paralysis virus (ABPV) is commonly detected in apparently healthy colonies, usually associated to Varroa destructor. Both viruses had been detected in most regions of the world, except in South America. In this work, we detected CBPV and ABPV in samples of Uruguayan honeybees by RT-PCR. The detection of both viruses in different provinces and the fact that most of the analyzed samples were infected, suggest that, they are widely spread in the region. This is the first record of the presence of CBPV and ABPV in Uruguay and South America.

  17. Widespread occurrence of honey bee pathogens in solitary bees.

    Science.gov (United States)

    Ravoet, Jorgen; De Smet, Lina; Meeus, Ivan; Smagghe, Guy; Wenseleers, Tom; de Graaf, Dirk C

    2014-10-01

    Solitary bees and honey bees from a neighbouring apiary were screened for a broad set of putative pathogens including protists, fungi, spiroplasmas and viruses. Most sampled bees appeared to be infected with multiple parasites. Interestingly, viruses exclusively known from honey bees such as Apis mellifera Filamentous Virus and Varroa destructor Macula-like Virus were also discovered in solitary bees. A microsporidium found in Andrena vaga showed most resemblance to Nosema thomsoni. Our results suggest that bee hives represent a putative source of pathogens for other pollinators. Similarly, solitary bees may act as a reservoir of honey bee pathogens. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Calibración y validación de un modelo en computador para simular el golpe de ariete en redes cerradas.

    OpenAIRE

    Velásquez Hidalgo, Carlos Férnando; Toro Botero, Francisco Mauricio

    2006-01-01

    El golpe de ariete, como fenómeno transitorio, ha sido un tema de estudio de la hidráulica, por sus efectos destructores en sistemas de alta presión como los conductos abastecedores de turbinas en centrales hidroeléctricas. Aunque el tema esté muy estudiado y analizado para conductos simples, comienza a aflorar la inquietud de simular este fenómeno en redes cerradas, las cuales están propensas a experimentar el golpe de ariete. Se presenta un modelo computacional para simular el Golpe de Arie...

  19. Application of multi-way analysis to UV-visible spectroscopy, gas chromatography and electronic nose data for wine ageing evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Prieto, N. [Department of Condensed Matter Physics, Faculty of Sciences, University of Valladolid, 47011 Valladolid (Spain); Department of Inorganic Chemistry, Escuela de Ingenierias Industriales, University of Valladolid, Paseo del Cauce, 59, 47011 Valladolid (Spain); Rodriguez-Mendez, M.L. [Department of Inorganic Chemistry, Escuela de Ingenierias Industriales, University of Valladolid, Paseo del Cauce, 59, 47011 Valladolid (Spain); Leardi, R. [Department of Pharmaceutical and Food Chemistry and Technology, University of Genoa, Via Brigata Salerno 13, I-16147 8 Genoa (Italy); Oliveri, P., E-mail: oliveri@dictfa.unige.it [Department of Pharmaceutical and Food Chemistry and Technology, University of Genoa, Via Brigata Salerno 13, I-16147 8 Genoa (Italy); Hernando-Esquisabel, D.; Iniguez-Crespo, M. [Gobierno de la Rioja, Consejeria de Agricultura y Alimentacion, Estacion Enologica, Breton de los Herreros 4, 26200 Haro, La Rioja (Spain); Saja, J.A. de [Department of Condensed Matter Physics, Faculty of Sciences, University of Valladolid, 47011 Valladolid (Spain)

    2012-03-16

    Highlights: Black-Right-Pointing-Pointer Wine samples were analytically characterised according to their ageing process. Black-Right-Pointing-Pointer Signals from a sensor-based electronic nose were fused with GC-MS and UV-visible data. Black-Right-Pointing-Pointer The study involved 6 periodical determinations of 20 variables on 6 different wines. Black-Right-Pointing-Pointer Multi-way analysis allowed to efficiently extract the maximum information from data. Black-Right-Pointing-Pointer Multi-way methods represent the most suitable tool for processing three-mode data. - Abstract: In this study, a multi-way method (Tucker3) was applied to evaluate the performance of an electronic nose for following the ageing of red wines. The odour evaluation carried out with the electronic nose was combined with the quantitative analysis of volatile composition performed by GC-MS, and colour characterisation by UV-visible spectroscopy. Thanks to Tucker3, it was possible to understand connections among data obtained from these three different systems and to estimate the effect of different sources of variability on wine evaluation. In particular, the application of Tucker3 supplied a global visualisation of data structure, which was very informative to understand relationships between sensors responses and chemical composition of wines. The results obtained indicate that the analytical methods employed are useful tools to follow the wine ageing process, to differentiate wine samples according to ageing type (either in barrel or in stainless steel tanks with the addition of small oak wood pieces) and to the origin (French or American) of the oak wood. Finally, it was possible to designate the volatile compounds which play a major role in such a characterisation.

  20. Investigation of kinetics and thermodynamics of DNA hybridization by means of 2-D fluorescence spectroscopy and soft/hard modeling techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ebrahimi, Sara; Kompany-Zareh, Mohsen, E-mail: kmpz@dr.com

    2016-02-04

    Reversible hybridization reaction plays a key role in fundamental biological processes, in many laboratory techniques, and also in DNA based sensing devices. Comprehensive investigation of this process is, therefore, essential for the development of more sophisticated applications. Kinetics and thermodynamics of the hybridization reaction, as a second order process, are systematically investigated with the aid of the soft and hard chemometric methods. Labeling two complementary 21 mer DNA single strands with FAM and Texas red fluorophores, enabled recording of the florescence excitation−emission matrices during the experiments which led to three-way data sets. The presence of fluorescence resonance energy transfer in excitation and emission modes and the closure in concentration mode, made the three-way data arrays rank deficient. To acquire primary chemical information, restricted Tucker3 as a soft method was employed. Herein a model-based method, hard restricted trilinear decomposition, is introduced for in depth analysis of rank deficient three-way data sets. By employing proposed hard method, the nonlinear model parameters as well as the correct profiles could be estimated. In addition, a simple constraint is presented to extract chemically reasonable output profiles regarding the core elements of restricted Tucker3 model. - Highlights: • Hard restricted trilinear decomposition (HrTD) was introduced for model-based analysis of three-way rank deficient data. • DNA hybridization was investigated by two-dimensional fluorescence spectroscopy and soft/hard multi-way techniques. • Restricted Tucker3 analysis enabled accurate estimation of pure FRET profiles in the hybridized form. • HrTD was successfully employed to estimate kinetic and equilibrium parameters of DNA hybridization system. • The performance of the proposed methods in response to different physical stimuli was successfully evaluated.

  1. The "normal" elongation of river basins

    Science.gov (United States)

    Castelltort, Sebastien

    2013-04-01

    The spacing between major transverse rivers at the front of Earth's linear mountain belts consistently scales with about half of the mountain half-width [1], despite strong differences in climate and rock uplift rates. Like other empirical measures describing drainage network geometry this result seems to indicate that the form of river basins, among other properties of landscapes, is invariant. Paradoxically, in many current landscape evolution models, the patterns of drainage network organization, as seen for example in drainage density and channel spacing, seem to depend on both climate [2-4] and tectonics [5]. Hovius' observation [1] is one of several unexplained "laws" in geomorphology that still sheds mystery on how water, and rivers in particular, shape the Earth's landscapes. This narrow range of drainage network shapes found in the Earth's orogens is classicaly regarded as an optimal catchment geometry that embodies a "most probable state" in the uplift-erosion system of a linear mountain belt. River basins currently having an aspect away from this geometry are usually considered unstable and expected to re-equilibrate over geological time-scales. Here I show that the Length/Width~2 aspect ratio of drainage basins in linear mountain belts is the natural expectation of sampling a uniform or normal distribution of basin shapes, and bears no information on the geomorphic processes responsible for landscape development. This finding also applies to Hack's [6] law of river basins areas and lengths, a close parent of Hovius' law. [1]Hovius, N. Basin Res. 8, 29-44 (1996) [2]Simpson, G. & Schlunegger, F. J. Geophys. Res. 108, 2300 (2003) [3]Tucker, G. & Bras, R. Water Resour. Res. 34, 2751-2764 (1998) [4]Tucker, G. & Slingerland, R. Water Resour. Res. 33, 2031-2047 (1997) [5]Tucker, G. E. & Whipple, K. X. J. Geophys. Res. 107, 1-1 (2002) [6]Hack, J. US Geol. Surv. Prof. Pap. 294-B (1957)

  2. Application of multi-way analysis to UV–visible spectroscopy, gas chromatography and electronic nose data for wine ageing evaluation

    International Nuclear Information System (INIS)

    Prieto, N.; Rodriguez-Méndez, M.L.; Leardi, R.; Oliveri, P.; Hernando-Esquisabel, D.; Iñiguez-Crespo, M.; Saja, J.A. de

    2012-01-01

    Highlights: ► Wine samples were analytically characterised according to their ageing process. ► Signals from a sensor-based electronic nose were fused with GC–MS and UV–visible data. ► The study involved 6 periodical determinations of 20 variables on 6 different wines. ► Multi-way analysis allowed to efficiently extract the maximum information from data. ► Multi-way methods represent the most suitable tool for processing three-mode data. - Abstract: In this study, a multi-way method (Tucker3) was applied to evaluate the performance of an electronic nose for following the ageing of red wines. The odour evaluation carried out with the electronic nose was combined with the quantitative analysis of volatile composition performed by GC–MS, and colour characterisation by UV–visible spectroscopy. Thanks to Tucker3, it was possible to understand connections among data obtained from these three different systems and to estimate the effect of different sources of variability on wine evaluation. In particular, the application of Tucker3 supplied a global visualisation of data structure, which was very informative to understand relationships between sensors responses and chemical composition of wines. The results obtained indicate that the analytical methods employed are useful tools to follow the wine ageing process, to differentiate wine samples according to ageing type (either in barrel or in stainless steel tanks with the addition of small oak wood pieces) and to the origin (French or American) of the oak wood. Finally, it was possible to designate the volatile compounds which play a major role in such a characterisation.

  3. Reference hearing threshold levels for chirp signals delivered by an ER-3A insert earphone

    DEFF Research Database (Denmark)

    Gøtsche-Rasmussen, Kristian; Poulsen, Torben; Elberling, Claus

    2012-01-01

    back from a Tucker Davies Technologies System II, and a Matlab program controlled the test setup. The results are specified in dB peak-to-peak equivalent threshold sound pressure levels (dB peETSPL). Study sample: The test group consisted of 25 otologically-normal young adults (age 18–25 years......Objective: To establish reference hearing threshold levels for chirps and frequency-specific chirps. Design: Hearing thresholds were determined monaurally for broad-band chirps and octave-band chirps using the Etymotic Research, ER-3A insert earphone. The chirps were presented using two repetition...

  4. Structural reliability analysis under evidence theory using the active learning kriging model

    Science.gov (United States)

    Yang, Xufeng; Liu, Yongshou; Ma, Panke

    2017-11-01

    Structural reliability analysis under evidence theory is investigated. It is rigorously proved that a surrogate model providing only correct sign prediction of the performance function can meet the accuracy requirement of evidence-theory-based reliability analysis. Accordingly, a method based on the active learning kriging model which only correctly predicts the sign of the performance function is proposed. Interval Monte Carlo simulation and a modified optimization method based on Karush-Kuhn-Tucker conditions are introduced to make the method more efficient in estimating the bounds of failure probability based on the kriging model. Four examples are investigated to demonstrate the efficiency and accuracy of the proposed method.

  5. A Simply Constrained Optimization Reformulation of KKT Systems Arising from Variational Inequalities

    International Nuclear Information System (INIS)

    Facchinei, F.; Fischer, A.; Kanzow, C.; Peng, J.-M.

    1999-01-01

    The Karush-Kuhn-Tucker (KKT) conditions can be regarded as optimality conditions for both variational inequalities and constrained optimization problems. In order to overcome some drawbacks of recently proposed reformulations of KKT systems, we propose casting KKT systems as a minimization problem with nonnegativity constraints on some of the variables. We prove that, under fairly mild assumptions, every stationary point of this constrained minimization problem is a solution of the KKT conditions. Based on this reformulation, a new algorithm for the solution of the KKT conditions is suggested and shown to have some strong global and local convergence properties

  6. Optimality Conditions for Nondifferentiable Multiobjective Semi-Infinite Programming Problems

    Directory of Open Access Journals (Sweden)

    D. Barilla

    2016-01-01

    Full Text Available We have considered a multiobjective semi-infinite programming problem with a feasible set defined by inequality constraints. First we studied a Fritz-John type necessary condition. Then, we introduced two constraint qualifications and derive the weak and strong Karush-Kuhn-Tucker (KKT in brief types necessary conditions for an efficient solution of the considered problem. Finally an extension of a Caristi-Ferrara-Stefanescu result for the (Φ,ρ-invexity is proved, and some sufficient conditions are presented under this weak assumption. All results are given in terms of Clark subdifferential.

  7. Numerical simulation of experimental data from planar SIS mixers with integrated tuning elements

    International Nuclear Information System (INIS)

    Mears, C.A.; Hu, Qing; Richards, P.L.

    1988-08-01

    We have used the full Tucker theory including the quantum susceptance to fit data from planar lithographed mm-wave mixers with bow tie antennas and integrated RF coupling elements. Essentially perfect fits to pumped IV curves have been obtained. The deduced imbedding admittances agree well with those independently calculated from the geometry of the antenna and matching structures. We find that the quantum susceptance is essential to the fit and thus to predictions of the mixer performance. For junctions with moderately sharp gap structures, the quantum susceptance is especially important in the production of steps with low and/or negative dynamic conductance. 15 refs., 4 figs

  8. Computer science handbook

    CERN Document Server

    Tucker, Allen B

    2004-01-01

    Due to the great response to the famous Computer Science Handbook edited by Allen B. Tucker, … in 2004 Chapman & Hall/CRC published a second edition of this comprehensive reference book. Within more than 70 chapters, every one new or significantly revised, one can find any kind of information and references about computer science one can imagine. … All in all, there is absolute nothing about computer science that can not be found in the encyclopedia with its 110 survey articles …-Christoph Meinel, Zentralblatt MATH

  9. "A Is A": Spider-Man, Ayn Rand, and What Man Ought to Be

    OpenAIRE

    Brühwiler, Claudia Franziska

    2014-01-01

    In 1979, writer Tom DeFalco was paired with artist and cocreator of Spider-Man, Steve Ditko, to work on an issue of Machine Man, one of the many superheroes populating the universe of Marvel Comics. Instead of the usual introduction and business chatter, Ditko challenged DeFalco during a first conversation: "Are you Tom? What gives you the right to write about heroes?" (Tucker 2012). By the time of this exchange, Ditko had not only (co-) created and continued numerous superhero stories, rangi...

  10. Multifunctional Composite Nanofibers for Smart Structures

    Science.gov (United States)

    2011-10-13

    such as the Shape Memory Alloy (SMA) and/or shape memory polymer (SMP) and other hybrid systems. We specifically attempt to answer the following...stress induced from SiNP expansion upon alloying with Li ions. The cycling performance of core-shell CNF/SiNP composite is compared with that of non...Ayranci, Frank Ko, Tucker Howie, MinoruTaya, “Shape memory effect of a thermoset polymer and its fiber reinforced composites, submitted to the 18th

  11. Reply to: Analysis of the effects of fractionated irradiation to the rat heart (by E. van Rongen)

    International Nuclear Information System (INIS)

    Guttenberger, R.

    1987-01-01

    The applicability of the linear quadratic (LQ) model in the analysis of the data presented by Lauk et al. (Radiotherapy. Oncol. 8: 363-367, 1987) is investigated with the linear regression method of Tucker, by simulating fractionated irradiation experiments on tissues with α/β values varying from 1 to 20, starting from theoretical iso-effect doses. It turns out that the LQ model is unreliable for small (∼ 1) α/β values using the error probability p=0.05 and that the sensitivity of the linear regression method is dependent on the underlying α/β. 3 refs.; 1 table

  12. Decomposition and classification of electroencephalography data

    DEFF Research Database (Denmark)

    Frølich, Laura

    . To enforce orthonormality of projection matrices, objective functions quantifying class discrimination were optimised on a cross-product of Stiefel (orthonormal matrix) manifolds. Supervised feature extraction outperformed unsupervised methods, but the choice of supervised method mattered less. We suggested......_MARC was also used to inspect effects of artefacts on motor imagery based Brain-Computer Interfaces (BCIs) in two studies, where removing artefactual ICs had little performance impact. Finally, we investigated multi-linear classification on single trials of EEG data, proposing a rigorous optimisation approach...... completions of methods to include both PARAFAC and Tucker structures. The two structures provided similar performances, making the more interpretable PARAFAC models appealing....

  13. Innovation is Everybody's Business How to Make Yourself Indispensable in Today's Hypercompetitive World

    CERN Document Server

    Tucker, Robert B

    2010-01-01

    Innovation isn't something you do after you get your work done. It's how you do your work. Organizations all over the world are shedding jobs in record numbers. Yet today, they are desperately in need of people with the abilities and skills to think ahead of the curve, delight customers, motivate colleagues, slash costs, and achieve unconventional results. In this practical road map to becoming irreplaceable, global innovation guru and bestselling author Robert B. Tucker reveals why honing your I-Skills (Innovation Skills) may be the smartest career move you'll make. Based on interviews with f

  14. Undergraduate Convexity

    DEFF Research Database (Denmark)

    Lauritzen, Niels

    -Motzkin elimination, the theory is developed by introducing polyhedra, the double description method and the simplex algorithm, closed convex subsets, convex functions of one and several variables ending with a chapter on convex optimization with the Karush-Kuhn-Tucker conditions, duality and an interior point......Based on undergraduate teaching to students in computer science, economics and mathematics at Aarhus University, this is an elementary introduction to convex sets and convex functions with emphasis on concrete computations and examples. Starting from linear inequalities and Fourier...

  15. SXR, A Novel Target for Breast Cancer Therapeutics

    Science.gov (United States)

    2007-04-01

    2000) J. BoneMiner. Res. 15, 515–521 7. Booth , S. L., Tucker, K. L., Chen, H., Hannan, M. T., Gagnon, D. R., Cupples, L. A., Wilson, P. W., Ordovas...J. Bone Miner. Res. 17, 1180–1189 31. Deak, F., Piecha, D., Bachrati, C., Paulsson, M., and Kiss , I. (1997) J. Biol. Chem. 272, 9268–9274 32. Piecha...D., Muratoglu, S., Morgelin, M., Hauser, N., Studer, D., Kiss , I., Paulsson, M., and Deak, F. (1999) J. Biol. Chem. 274, 13353–13361 33. Piecha, D

  16. A general numerical analysis of the superconducting quasiparticle mixer

    Science.gov (United States)

    Hicks, R. G.; Feldman, M. J.; Kerr, A. R.

    1985-01-01

    For very low noise millimeter-wave receivers, the superconductor-insulator-superconductor (SIS) quasiparticle mixer is now competitive with conventional Schottky mixers. Tucker (1979, 1980) has developed a quantum theory of mixing which has provided a basis for the rapid improvement in SIS mixer performance. The present paper is concerned with a general method of numerical analysis for SIS mixers which allows arbitrary terminating impedances for all the harmonic frequencies. This analysis provides an approach for an examination of the range of validity of the three-frequency results of the quantum mixer theory. The new method has been implemented with the aid of a Fortran computer program.

  17. Relationship between herbaceous biomass and 1km (2) advanced very high resolution radiometer (AVHRR) NDVI in Kruger National Park, South Africa

    CSIR Research Space (South Africa)

    Wessels, Konrad J

    2006-03-01

    Full Text Available biomass and 1-km2 Advanced Very High Resolution Radiometer (AVHRR) NDVI in Kruger National Park, South Africa K. J. WESSELS*{, S. D. PRINCE{, N. ZAMBATIS{, S. MACFADYEN{, P. E. FROST§" and D. VAN ZYL§ {Department of Geography, University of Maryland... production (Prince and Justice 1991, Tucker et al. 1991a,b, Myneni et al. *Corresponding author. Email: wessels@geog.umd.edu International Journal of Remote Sensing Vol. 27, No. 5, 10 March 2006, 951–973 International Journal of Remote Sensing ISSN 0143...

  18. Product-Improvement Test (Phase II), Jetcal Tester, Model H119A.

    Science.gov (United States)

    1969-03-05

    Ao—A0 51 113 ARMY AVIATION ‘Cs’ BOARD FORT tUCKER ALA — P*OOUCTeII ROVEMCNT TEST ( FHAS ~ I I ) . JETCAL TESTER, MODEL M119A~~’ETC(U) MAR S9...Phase i i ) , Jetcal Tester , Model H 119A , USATECOM Project No. 4-6-5011-03 b . No fur ther consideration be given to the TEMPCAL heater probe as a...essen t i a l component of the Jetcal Tester. e. The service manual instruct ions for con t inu i ty te s t ing of EG1 thermocouples be revised to

  19. W-Band Technology and Techniques for Analog Millimeter-Wave Photonics

    Science.gov (United States)

    2015-08-19

    Chang and C. Liu, “1-100 GHz microwave photonic link technologies for next- generation WiFi and 5G wireless communications,” in IEEE Topical Meeting on...high- speed optical transmission,” Opt. Exp., vol. 14, no. 9, pp. 3767-3775, Apr. 2006. [17] R. S. Tucker, G. Eisenstein, and S. K. Korotky...Sept. 1990. [20] R. Hui, B. Zhu, R. Huang, C. T. Allen, K. R. Demarest, and D. Richards, “Subcarrier multiplexing for high- speed optical transmission

  20. Contra Copyright, Again

    OpenAIRE

    Wendy McElroy

    2011-01-01

    This revised version of the author’s 1985 article “Contra Copyright” includes a new, introductory section explaining the background of the author’s path to copyright abolitionism. The main article surveys various libertarian debates on this issue, including the anti-intellectual property (IP) views of Benjamin Tucker and the pro-IP views of Lysander Spooner. McElroy argues that the issue of copyright hinges on the question: can ideas be property? Because only scarce goods can be property, and...

  1. American Neutrality in The 20th Century: The Impossible Dream

    Science.gov (United States)

    1995-01-01

    Digest oflnternationalLaw 11, 180; Robert W. Tucker, ILS XLX (sic) (1955), 197, 199n, 258-259. See also Hans Kelsen , ILS XLIX (1954), 157 for a summary...the Modem System of International Law," Recueil des Cours 80 (1952), i:482; also quoted at Whiteman, 11, 150; see also Hans Kelsen , ILS XLIX (1954...5, 993-997 and Kelsen , 166n-167n for the President’s address; "From now on, if German or Italian vessels of war enter the waters the protection of

  2. Host Specificity in the Honeybee Parasitic Mite, Varroa spp. in Apis mellifera and Apis cerana.

    Directory of Open Access Journals (Sweden)

    Alexis L Beaurepaire

    Full Text Available The ectoparasitic mite Varroa destructor is a major global threat to the Western honeybee Apis mellifera. This mite was originally a parasite of A. cerana in Asia but managed to spill over into colonies of A. mellifera which had been introduced to this continent for honey production. To date, only two almost clonal types of V. destructor from Korea and Japan have been detected in A. mellifera colonies. However, since both A. mellifera and A. cerana colonies are kept in close proximity throughout Asia, not only new spill overs but also spill backs of highly virulent types may be possible, with unpredictable consequences for both honeybee species. We studied the dispersal and hybridisation potential of Varroa from sympatric colonies of the two hosts in Northern Vietnam and the Philippines using mitochondrial and microsatellite DNA markers. We found a very distinct mtDNA haplotype equally invading both A. mellifera and A. cerana in the Philippines. In contrast, we observed a complete reproductive isolation of various Vietnamese Varroa populations in A. mellifera and A. cerana colonies even if kept in the same apiaries. In light of this variance in host specificity, the adaptation of the mite to its hosts seems to have generated much more genetic diversity than previously recognised and the Varroa species complex may include substantial cryptic speciation.

  3. Effect of pollen extract supplementation on the varroatosis tolerance of honey bee (Apis mellifera) larvae reared in vitro.

    Science.gov (United States)

    Piou, Vincent; Tabart, Jérémy; Hemptinne, Jean-Louis; Vétillard, Angélique

    2018-01-01

    As the main source of lipids and proteins in honey bees, pollen is a major nutrient provider involved in development and health and has been studied for tolerance stimulation against pathogens and parasites. In the case of Varroa destructor Anderson & Trueman (Acari, Mesostigmata: Varroidae) parasitization, the lack of a complete laboratory system to rear both the bee larva and the acarian parasite limited the studies concerning larval nutrition effects on the bee tolerance and resistance against varroatosis. Due to the development of this complete rearing protocol, we managed to feed young honey bee larvae with pollen supplemented solutions and to study the effect on their later development under parasitism conditions. In our experimental conditions, pollen influences neither the deformity rate, nor the survival of bees both parasitized and unparasitized. However, pollen extract supplementation seems to significantly impact the weight of the spinning bee larvae without having an effect on the physiological weight loss during pupation, so the differences found at the larval stage remain the same as at emergence. Varroa has a deleterious effect on bee pupae and led to a steady increase of the physiological weight loss experienced during metamorphosis. Interestingly, this ponderal loss associated with Varroa parasitization seems to be reduced in the polyfloral pollen supplementation condition. Altogether, this work is to our knowledge the first to study in laboratory conditions the impact of larval nutrition on the tolerance to parasitism. A diverse pollen diet may be beneficial to the bees' tolerance against V. destructor parasitism.

  4. A real-time PCR method for quantification of the total and major variant strains of the deformed wing virus.

    Directory of Open Access Journals (Sweden)

    Emma L Bradford

    Full Text Available European honey bees (Apis mellifera are critically important to global food production by virtue of their pollination services but are severely threatened by deformed wing virus (DWV especially in the presence of the external parasite Varroa destructor. DWV exists as many viral strains with the two major variants (DWV-A and DWV-B varying in virulence. A single plasmid standard was constructed containing three sections for the specific determination of DWV-A (VP2 capsid region, DWV-B (IRES and a conserved region suitable for total DWV (helicase region. The assays were confirmed as specific and discriminatory with limits of detections of 25, 25 and 50 genome equivalents for DWV-A, DWV-B and total-DWV, respectively. The methods were successfully tested on Apis mellifera and V. destructor samples with varying DWV profiles. The new method determined a more accurate total DWV titre in samples with substantial DWV-B than the method currently described in the COLOSS Beebook. The proposed assays could be utilized for the screening of large quantities of bee material for both a total DWV load overview along with more detailed investigations into DWV-A and DWV-B profiles.

  5. Influence of Cultivars and Seed Thermal Treatment on the Development of Fungal Pathogens in Carrot and Onion Plants

    Directory of Open Access Journals (Sweden)

    Martin Koudela

    2016-01-01

    Full Text Available Carrot and onion are vegetables representing an important segment of fresh market. They suffer from serious fungal diseases that can inflict great damage on crops, i.e. alternaria leaf blight, peronospora downy mildew, and botrytis neck rot. The resistance of selected carrot and onion cultivars important for the production of vegetables in the Czech Republic was tested by exposure to targeted infection by the above fungal pathogens. The exposure of eleven carrot cultivars to spores of Alternaria dauci showed that the most resistant and sensitive cultivars were Katrin, Cortina F1, Afalon F1 and Favorit, Tinga, Berlika F1, respectively. A targeted infection of onion cultivars with Botrytis aclada clustered them into three groups: Amfora F1, Bolero, Tosca, Triumf F1 (strong resistance, Avalon, Grenada (medium resistance, Alice, Karmen, Všetana (low resistance. Similar groups were distinguished also after the infection with Peronospora destructor: Avalon, Bolero, Tosca (strong resistance, Alice, Amfora F1, Grenada, Karmen, Triumf F1 (medium resistance,Všetana (low resistance. Hot water treatment of carrot seeds applied after the inoculation with A. dauci decreased the development of the infection 1.3-2.3-fold, whereas the protective effect observed with onion seeds against the infection by P. destructor and B. aclada was lower.

  6. Evidence for positive selection and recombination hotspots in Deformed wing virus (DWV).

    Science.gov (United States)

    Dalmon, A; Desbiez, C; Coulon, M; Thomasson, M; Le Conte, Y; Alaux, C; Vallon, J; Moury, B

    2017-01-25

    Deformed wing virus (DWV) is considered one of the most damaging pests in honey bees since the spread of its vector, Varroa destructor. In this study, we sequenced the whole genomes of two virus isolates and studied the evolutionary forces that act on DWV genomes. The isolate from a Varroa-tolerant bee colony was characterized by three recombination breakpoints between DWV and the closely related Varroa destructor virus-1 (VDV-1), whereas the variant from the colony using conventional Varroa management was similar to the originally described DWV. From the complete sequence dataset, nine independent DWV-VDV-1 recombination breakpoints were detected, and recombination hotspots were found in the 5' untranslated region (5' UTR) and the conserved region encoding the helicase. Partial sequencing of the 5' UTR and helicase-encoding region in 41 virus isolates suggested that most of the French isolates were recombinants. By applying different methods based on the ratio between non-synonymous (dN) and synonymous (dS) substitution rates, we identified four positions that showed evidence of positive selection. Three of these positions were in the putative leader protein (Lp), and one was in the polymerase. These findings raise the question of the putative role of the Lp in viral evolution.

  7. Antennae hold a key to Varroa-sensitive hygiene behaviour in honey bees.

    Science.gov (United States)

    Mondet, Fanny; Alaux, Cédric; Severac, Dany; Rohmer, Marine; Mercer, Alison R; Le Conte, Yves

    2015-05-22

    In honey bees, Varroa sensitive hygiene (VSH) behaviour, which involves the detection and removal of brood parasitised by the mite Varroa destructor, can actively participate in the survival of colonies facing Varroa outbreaks. This study investigated the mechanisms of VSH behaviour, by comparing the antennal transcriptomes of bees that do and do not perform VSH behaviour. Results indicate that antennae likely play a key role in the expression of VSH behaviour. Comparisons with the antennal transcriptome of nurse and forager bees suggest that VSH profile is more similar to that of nurse bees than foragers. Enhanced detection of certain odorants in VSH bees may be predicted from transcriptional patterns, as well as a higher metabolism and antennal motor activity. Interestingly, Deformed wing virus/Varroa destructor virus infections were detected in the antennae, with higher level in non-VSH bees; a putative negative impact of viral infection on bees' ability to display VSH behaviour is proposed. These results bring new perspectives to the understanding of VSH behaviour and the evolution of collective defence by focusing attention on the importance of the peripheral nervous system. In addition, such data might be useful for promoting marker-assisted selection of honey bees that can survive Varroa infestations.

  8. Response of Pinus ponderosa Seedlings to Stylet-Bearing Nematodes

    Science.gov (United States)

    Viglierchio, D. R.

    1979-01-01

    Of 12 stylet-bearing nematodes used for inoculations, Pratylenchus penetrans, P. brachyurus, P. vulnus, Ditylenchus destructor, Meloidogyne incognita, M. javanica, and M. hapla reproduced on Pinus ponderosa, while Xiphinema index, Aphelenchus avenae, Paratylenehus neoamblycephalus, Tylenchulus semipenetrans, and Macroposthonia xenoplax did not. P. vulnus, P. brachyurus, P. penetrans, A. avenae, D. destructor, T. semipenetrans, and P. neoamblycephalus significantly suppressed both the shoot and root wet weights of ponderosa pine seedlings obtained from stands in five different locations. X. index significantly suppressed root wet weights, M. xenoplax siguificantly suppressed shoot wet weight, and M. incognita, M. javanica, and M. hapla suppressed neither at the inoculation levels used. Injurious nematodes tended to suppress root growth more than shoot growth. Seedlings from two locations produced greater shoot growth wet weight than did seedlings from the other three locations. The more injurious nematodes tended to cause an increase in the water content of shoots. Frequency analyses of seedling population shoot-root ratios indicated that ponderosa pine seedlings could be selected for better shoot-root ratios as well as for resistance to several pathogenic nematodes. PMID:19300659

  9. Rapid parallel evolution overcomes global honey bee parasite.

    Science.gov (United States)

    Oddie, Melissa; Büchler, Ralph; Dahle, Bjørn; Kovacic, Marin; Le Conte, Yves; Locke, Barbara; de Miranda, Joachim R; Mondet, Fanny; Neumann, Peter

    2018-05-16

    In eusocial insect colonies nestmates cooperate to combat parasites, a trait called social immunity. However, social immunity failed for Western honey bees (Apis mellifera) when the ectoparasitic mite Varroa destructor switched hosts from Eastern honey bees (Apis cerana). This mite has since become the most severe threat to A. mellifera world-wide. Despite this, some isolated A. mellifera populations are known to survive infestations by means of natural selection, largely by supressing mite reproduction, but the underlying mechanisms of this are poorly understood. Here, we show that a cost-effective social immunity mechanism has evolved rapidly and independently in four naturally V. destructor-surviving A. mellifera populations. Worker bees of all four 'surviving' populations uncapped/recapped worker brood cells more frequently and targeted mite-infested cells more effectively than workers in local susceptible colonies. Direct experiments confirmed the ability of uncapping/recapping to reduce mite reproductive success without sacrificing nestmates. Our results provide striking evidence that honey bees can overcome exotic parasites with simple qualitative and quantitative adaptive shifts in behaviour. Due to rapid, parallel evolution in four host populations this appears to be a key mechanism explaining survival of mite infested colonies.

  10. Stable genetic diversity despite parasite and pathogen spread in honey bee colonies

    Science.gov (United States)

    Jara, Laura; Muñoz, Irene; Cepero, Almudena; Martín-Hernández, Raquel; Serrano, José; Higes, Mariano; De la Rúa, Pilar

    2015-10-01

    In the last decades, the rapid spread of diseases, such as varroosis and nosemosis, associated with massive honey bee colonies mortality around the world has significantly decreased the number and size of honey bee populations and possibly their genetic diversity. Here, we compare the genetic diversity of Iberian honey bee colonies in two samplings performed in 2006 and 2010 in relation to the presence of the pathogenic agents Nosema apis, Nosema ceranae, and Varroa destructor in order to determine whether parasite and pathogen spread in honey bee colonies reflects changes in genetic diversity. We found that the genetic diversity remained similar, while the incidence of N. ceranae increased and the incidence of N. apis and V. destructor decreased slightly. These results indicate that the genetic diversity was not affected by the presence of these pathogenic agents in the analyzed period. However, the two groups of colonies with and without Nosema/Varroa detected showed significant genetic differentiation (G test). A detailed analysis of the allelic segregation of microsatellite loci in Nosema/Varroa-negative colonies and parasitized ones revealed two outlier loci related to genes involved in immune response.

  11. Stable genetic diversity despite parasite and pathogen spread in honey bee colonies.

    Science.gov (United States)

    Jara, Laura; Muñoz, Irene; Cepero, Almudena; Martín-Hernández, Raquel; Serrano, José; Higes, Mariano; De la Rúa, Pilar

    2015-10-01

    In the last decades, the rapid spread of diseases, such as varroosis and nosemosis, associated with massive honey bee colonies mortality around the world has significantly decreased the number and size of honey bee populations and possibly their genetic diversity. Here, we compare the genetic diversity of Iberian honey bee colonies in two samplings performed in 2006 and 2010 in relation to the presence of the pathogenic agents Nosema apis, Nosema ceranae, and Varroa destructor in order to determine whether parasite and pathogen spread in honey bee colonies reflects changes in genetic diversity. We found that the genetic diversity remained similar, while the incidence of N. ceranae increased and the incidence of N. apis and V. destructor decreased slightly. These results indicate that the genetic diversity was not affected by the presence of these pathogenic agents in the analyzed period. However, the two groups of colonies with and without Nosema/Varroa detected showed significant genetic differentiation (G test). A detailed analysis of the allelic segregation of microsatellite loci in Nosema/Varroa-negative colonies and parasitized ones revealed two outlier loci related to genes involved in immune response.

  12. ENVIRONMENTAL ASSESSMENT THE COASTAL AQUATORY OF KUIALNIK ESTUARY: MICROPHYTES, ZOOBENTHOS, DIVERSITY OF MICROBIOTA IN THE WATER AND PELOIDS

    Directory of Open Access Journals (Sweden)

    Polukarova L. A.

    2012-11-01

    Full Text Available We determined the concentration of macro- and microelements, such as: sodium, potassium, calcium, phosphorus, magnesium, iron, chlorides. We have also measured the concentration of hydrogen ions (pH and nitrogen of urea in samples of water and peloids which were taken from different places of Kuialnik estuary including territories around of such villages: Kotovka, Iliinka, Kovalevka, Novo Kovalevka, Belyayevsky district of Odessa region and such villages as: Korsuntsev, Krasnosilka, Kominternivskiy district of Odessa region.It was found that concentration of sodium and chlorides was high and increased from southern area to the northern part of Kuialnik estuary where volume of water is lesser. Hydrochemical investigation showed that concentration of macro- and microelements in the deep soils (peloids was lesser than in water samples and soils taken from the bottom of estuary. Investigation of tissue homogenates of brine shrimp (Artemia salina showed high enzyme activity of lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase. The same biochemical parameters tested in biomass of blue-green algae (cyanoprokaryota, unicellular algae Microcystis sp. where high activity of alkaline phosphatase and high concentration of calcium, potassium and iron were registered. We studied the following microbiota: ferro-oxidizing bacteria (destructors of iron, manganese-oxidizing bacteria (destructors of manganese, sulfate-reducing bacteria, mycobacterium, thiobacteria and representatives from some other microbial groups in the water and peloid samples. Such integrated environmental investigation allowed to assess the environmental situation in different plots of the Kuialnik estuary more properly and complete.

  13. Human Capital in the Entrepreneurship Ecosystem

    DEFF Research Database (Denmark)

    Østergaard, Annemarie; Marinova, Svetla Trifonova

    2018-01-01

    Since Adam Smith (1776) took consideration to human capital as an asset of economic value, academic interest has focused on the economic effects of human capital. In 1931, Schumpeter called for a focus on the individual entrepreneur or the creative destructor with his/her motives, wishes, aspirat......Since Adam Smith (1776) took consideration to human capital as an asset of economic value, academic interest has focused on the economic effects of human capital. In 1931, Schumpeter called for a focus on the individual entrepreneur or the creative destructor with his/her motives, wishes......, aspirations and activities when dealing with entrepreneurship and entrepreneurs. Along these lines, this paper focuses on an in-depth investigation of the domain of human capital in Isenbergs Entrepreneurship Ecosystem. It captures the entrepreneurial mindset of the highly complex individual as a requisite...... for entrepreneurial success and ultimately, for business growth and development. The increasing literature debating human capital confirms the relevance of locating and refining the factors for entrepreneurial success. Consequently, this paper improves the roadmap of Entrepreneurship Ecosystems by adding the innate...

  14. How I quit the government and learned how to ban the bomb

    Energy Technology Data Exchange (ETDEWEB)

    Smallbridge, J.

    1997-03-01

    A piece of equipment designed for destroying chemical warfare agents was discussed. A former scientist with Environment Canada, founder of ELI EcoLogic Inc., of Rockwood, Ontario, has designed and built the SE25 ELI Destructor, a `toxin-eating` machine that is portable, energy efficient and produces no emissions. The machine was designed primarily to handle toxic wastes from industry through a process called gas phase chemical reduction. Waste is forced through high-pressure nozzles into a sealed heated chamber to which hydrogen is added to force the toxic molecules to break apart. Hydrogen chloride and water are then scrubbed from the methane gas. The methane is used to heat the unit and keep the process going; the water is pure enough for irrigation. The hydrogen chloride has many industrial uses and many willing buyers. Leftover contaminated material is a manageable fraction of its original volume. The fledgling environmental company landed a U.S. Army contract to destroy chemical weapons at the Aberdeen Proving Grounds and the Army`s Newport chemical depot in Indiana. Other units are at work at General Motors, and a unit is being built for service in Australia. The Destructor passed early trials testing with an high efficiency ratings, destroying 99.999999% of the toxic agents.

  15. Application of radiochemical methods for development of new biological preparation designed for soil bioremediation

    International Nuclear Information System (INIS)

    Kim, A.A.; Djuraeva, G.T.; Djumaniyazova, G.I.; Yadgarov, Kh.T.

    2006-01-01

    Full text: Internationally the bioremediation of agricultural lands contaminated by persistent chloroorganic compounds by means of the microbial methods are used as the most low-cost and the most effective. One of the factors reducing efficacy of microbial degradation, is often the low quantity of microorganisms - destructors in the soil. Therefore, we have designed bioremediation technology of soils, contaminated by organochlorine compounds, with use of the alive microorganisms as active agent. We developed the biological preparation containing 5 aboriginal active strains of bacteria - destructors of persistent chloroorganic compounds and investigated the ability of biological preparation to increase the bioremediation potential of contaminated soils. To carry out the investigation we developed the complex of radiochemical methods with use of tritium labeled PCBs, including the following methods: 1.The method to define the accumulation and degradation of PCBs in soil bacteria in culture allows determination of quantitative characteristics of bacterial strains. 2. The method to define the PCBs degradation by soil bacteria strains in model conditions in the soil allows to estimate the PCB-destructive activity of strains after introducing in soil. 3. A method to define the PCB-destructive activity of own microbiota of contaminated soil. 4. A method to define the effect of stimulation of the PCB-destructive activity of biological preparation and own microbiota of soil with the help of biofertilizers. By using the developed radiochemical methods we have carried out investigation on creation of new biological preparation on the basis of strains of soil bacteria - destructors of PCBs. We also determined the quality and quantity characteristics of HCCH and PCBs-destructive activity of new biological preparation. It is shown that the new biological preparation is capable of accumulation and destruction of the PCBs in culture and in soil at model conditions. Thus, the

  16. Lagrangian relaxation technique in power systems operation planning: Multipliers updating problem

    Energy Technology Data Exchange (ETDEWEB)

    Ruzic, S. [Electric Power Utility of Serbia, Belgrade (Yugoslavia)

    1995-11-01

    All Lagrangian relaxation based approaches to the power systems operation planning have an important common part: the Lagrangian multipliers correction procedure. It is the subject of this paper. Different approaches presented in the literature are discussed and an original method for the Lagrangian multipliers updating is proposed. The basic idea of this new method is to update Lagrangian multipliers trying to satisfy Khun-Tucker optimality conditions. Instead of the dual function maximization the `distance of optimality function` is defined and minimized. If Khun-Tucker optimality conditions are satisfied the value of this function is in range (-1,0); otherwise the function has a big positive value. This method called `the distance of optimality method` takes into account future changes in planning generations due to the Lagrangian multipliers updating. The influence of changes in a multiplier associated to one system constraint to the satisfaction of some other system requirements is also considered. The numerical efficiency of the proposed method is analyzed and compared with results obtained using the sub-gradient technique. 20 refs, 2 tabs

  17. Simultaneous tensor decomposition and completion using factor priors.

    Science.gov (United States)

    Chen, Yi-Lei; Hsu, Chiou-Ting; Liao, Hong-Yuan Mark

    2014-03-01

    The success of research on matrix completion is evident in a variety of real-world applications. Tensor completion, which is a high-order extension of matrix completion, has also generated a great deal of research interest in recent years. Given a tensor with incomplete entries, existing methods use either factorization or completion schemes to recover the missing parts. However, as the number of missing entries increases, factorization schemes may overfit the model because of incorrectly predefined ranks, while completion schemes may fail to interpret the model factors. In this paper, we introduce a novel concept: complete the missing entries and simultaneously capture the underlying model structure. To this end, we propose a method called simultaneous tensor decomposition and completion (STDC) that combines a rank minimization technique with Tucker model decomposition. Moreover, as the model structure is implicitly included in the Tucker model, we use factor priors, which are usually known a priori in real-world tensor objects, to characterize the underlying joint-manifold drawn from the model factors. By exploiting this auxiliary information, our method leverages two classic schemes and accurately estimates the model factors and missing entries. We conducted experiments to empirically verify the convergence of our algorithm on synthetic data and evaluate its effectiveness on various kinds of real-world data. The results demonstrate the efficacy of the proposed method and its potential usage in tensor-based applications. It also outperforms state-of-the-art methods on multilinear model analysis and visual data completion tasks.

  18. Parallel Tensor Compression for Large-Scale Scientific Data.

    Energy Technology Data Exchange (ETDEWEB)

    Kolda, Tamara G. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Ballard, Grey [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Austin, Woody Nathan [Univ. of Texas, Austin, TX (United States)

    2015-10-01

    As parallel computing trends towards the exascale, scientific data produced by high-fidelity simulations are growing increasingly massive. For instance, a simulation on a three-dimensional spatial grid with 512 points per dimension that tracks 64 variables per grid point for 128 time steps yields 8 TB of data. By viewing the data as a dense five way tensor, we can compute a Tucker decomposition to find inherent low-dimensional multilinear structure, achieving compression ratios of up to 10000 on real-world data sets with negligible loss in accuracy. So that we can operate on such massive data, we present the first-ever distributed memory parallel implementation for the Tucker decomposition, whose key computations correspond to parallel linear algebra operations, albeit with nonstandard data layouts. Our approach specifies a data distribution for tensors that avoids any tensor data redistribution, either locally or in parallel. We provide accompanying analysis of the computation and communication costs of the algorithms. To demonstrate the compression and accuracy of the method, we apply our approach to real-world data sets from combustion science simulations. We also provide detailed performance results, including parallel performance in both weak and strong scaling experiments.

  19. A quantitative model of regulator's preference factor (RPF) in electricity-environment coordinated regulation system

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Yulong; Fu, Shijun [Economy and Business Administration School of Chongqing University, Chongqing 400030 (China)

    2010-12-15

    This paper explores quantification of regulator's preference factor (RPF) in electricity-environment coordinated regulation system. Based on social welfare economics, we articulately depict RPF's qualitative concept and its economic meaning. Then, applying abstract functions (i.e., abstract social welfare function, abstract utility function, and abstract production function), we deduce the partial-social-welfare elasticity, and build the mathematics model of maximizing social welfare. We nest this elasticity into the model's Kuhn-Tucker conditions, and obtain RPF's definition formula. By solving the Kuhn-Tucker conditions, we get RPF's quantitative formula, which solves the problem of hard to quantify regulator's preference in electricity-environment coordinated regulation system. The result shows that RPF only has relationship to subsystems' production function, and is independent of social welfare function and subsystems' utility function. Finally, we provide an empirical research based on the western region of China from year 1995 to 2004. It reveals that regulator has relative stability preference to mitigating pollutants. And validity test confirms that the empirical result is fit well to the practice. The RPF is truly a more general and valid instrument to measure regulator's preference in its regulated field. (author)

  20. Reproducción de ruiseñor común (Luscinia megarhynchos en Gipuzkoa

    Directory of Open Access Journals (Sweden)

    ARIZAGA, J., MENDIBURU, A., ALDALUR, A., ALONSO, D., ARANGUREN, I... [et al.

    2010-01-01

    Full Text Available El Ruiseñor Común (Luscinia megarhynchos es un paseriforme transahariano ampliamente distribuido en el Paleártico Occidental, criando, principalmente, en el SW de Europa, al S de la isoterma de 19 grados en junio, y complementando así la distribución más nórdica y oriental del Ruiseñor Ruso (Luscinia luscinia. (CRAMP, 1988; TUCKER and HEATH, 1994; GRÜLL and FRACASSO, 1997. En Europa está presente la subespecie L. m. megarhynchos, encontrándose el 80% de la población en un total de cinco países: Francia, España, Italia, Bulgaria y Croacia (TUCKER and HEATH, 1994. En España está presente en todo el territorio, excepto en el Cantábrico, Canarias y áreas muy secas de la región mediterránea (INFANTE, 2003. Es típico de medios arbustivos densos, en bosques de galería y sotos, linderos, dehesas y huertas, e incluso parques urbanos (INFANTE, 2003. En Gipuzkoa, NOVAL (1967 lo citó como ave nidificante muy rara, principalmente en el interior, si bien ninguna cita se pudo confirmar. Actualmente, no consta como reproductor (AIERBE et al., 2001.

  1. Team decision problems with classical and quantum signals.

    Science.gov (United States)

    Brandenburger, Adam; La Mura, Pierfrancesco

    2016-01-13

    We study team decision problems where communication is not possible, but coordination among team members can be realized via signals in a shared environment. We consider a variety of decision problems that differ in what team members know about one another's actions and knowledge. For each type of decision problem, we investigate how different assumptions on the available signals affect team performance. Specifically, we consider the cases of perfectly correlated, i.i.d., and exchangeable classical signals, as well as the case of quantum signals. We find that, whereas in perfect-recall trees (Kuhn 1950 Proc. Natl Acad. Sci. USA 36, 570-576; Kuhn 1953 In Contributions to the theory of games, vol. II (eds H Kuhn, A Tucker), pp. 193-216) no type of signal improves performance, in imperfect-recall trees quantum signals may bring an improvement. Isbell (Isbell 1957 In Contributions to the theory of games, vol. III (eds M Drescher, A Tucker, P Wolfe), pp. 79-96) proved that, in non-Kuhn trees, classical i.i.d. signals may improve performance. We show that further improvement may be possible by use of classical exchangeable or quantum signals. We include an example of the effect of quantum signals in the context of high-frequency trading. © 2015 The Authors.

  2. Historical satellite data used to map Pan-Amazon forest cover

    Science.gov (United States)

    Kalluri, Satya; Desch, Arthur; Curry, Troy; Altstatt, Alice; Devers, Didier; Townshend, John; Tucker, Compton

    Deforestation in the Brazilian Amazon is well documented and the contributions of Brazilian deforestation to global change have been extensively discussed in both scientific and popular literature [e.g., Skole and Tucker, 1993]. However, deforestation within the non-Brazilian tropics of South America has received much less attention. The Pan-Amazon region covering Venezuela, Colombia, Ecuador, Peru, and Bolivia comprises ˜2 million km2 of tropical forest that is under increasing pressure from logging and development. Wall-to-wall high-resolution forest cover maps are needed to properly document the complex distribution patterns of deforestation in the Pan-Amazon [Tucker and Townshend, 2000]. The Deforestation Mapping Group at the University of Marylands Global Land Cover Facility is using Landsat data to generate tropical forest cover maps in this region (Figure l). The study shows that while rates of forest loss are generally lower than those in Brazil, there are hot spots where deforestation rates run as high as 2,200 km2 yr1.

  3. Evaluation of skin sensitivity in dogs bearing allergic dermatitis to standardized allergenic extract of house dust and storage mites Avaliação da sensibilidade de cães com dermatite alérgica a extratos padronizados de ácaros da poeira domiciliar

    Directory of Open Access Journals (Sweden)

    Victor E.S. Cunha

    2007-08-01

    Full Text Available The objective of the study was to evaluate whether allergenic extracts of five house dust and storage mite species standardized for humans might be used for the diagnosis of canine atopic dermatitis (CAD. Extracts of Dermatophagoides pteronyssinus (Pyroglyphidae, D. farinae (Pyroglyphidae, Blomia tropicalis (Glycyphagidae, Lepidoglyphus destructor (Glycyphagidae and Tyrophagus putrescentiae (Acaridae were evaluated by intradermal testing in 20 healthy dogs (control and 25 dogs with allergic dermatitis. A significant difference in the response was observed between the two groups (pO presente trabalho teve como objetivo avaliar se extratos alergênicos de cinco espécies de ácaros da poeira domiciliar e produtos armazenados, padronizados para humanos, podem ser utilizados no diagnóstico da dermatite atópica canina. Extratos de Dermatophagoides pteronyssinus (Pyroglyphidae, D. farinae (Pyroglyphidae, Blomia tropicalis (Glycyphagidae, Lepidoglyphus destructor (Glycyphagidae e Tyrophagus putrescentiae (Acaridae foram avaliados através de testes intradérmicos em 45 cães, dos quais 20 normais e 25 com dermatite alérgica. Uma diferença significativa foi observada no padrão de respostas obtidas dos dois grupos (p<0.05. Apenas um animal (5% do grupo controle reagiu ao teste cutâneo, enquanto que no grupo dos alérgicos 14 cães (56% apresentaram pelo menos uma reação positiva (odds ratio = 24.2. As maiores freqüências de reações positivas observadas no grupo dos alérgicos foram aos extratos de T. putres-centiae ou L. destructor, cada um induzindo reações em 10(40% cães. Os extratos de D. farinae, D. pteronyssinus e B. tropicalis foram responsáveis por reações positivas em 7(28%, 3(12% e 3(12% cães, respectivamente. Os extratos padronizados para humanos avaliados no presente estudo podem ser utilizados como complemento no diagnóstico da doença, assim como na seleção de alérgenos para a imunoterapia alérgeno-específica.

  4. An analysis of the daily precipitation variability in the Himalayan orogen using a statistical parameterisation and its potential in driving landscape evolution models with stochastic climatic forcing

    Science.gov (United States)

    Deal, Eric; Braun, Jean

    2015-04-01

    A current challenge in landscape evolution modelling is to integrate realistic precipitation patterns and behaviour into longterm fluvial erosion models. The effect of precipitation on fluvial erosion can be subtle as well as nonlinear, implying that changes in climate (e.g. precipitation magnitude or storminess) may have unexpected outcomes in terms of erosion rates. For example Tucker and Bras (2000) show theoretically that changes in the variability of precipitation (storminess) alone can influence erosion rate across a landscape. To complicate the situation further, topography, ultimately driven by tectonic uplift but shaped by erosion, has a major influence on the distribution and style of precipitation. Therefore, in order to untangle the coupling between climate, erosion and tectonics in an actively uplifting orogen where fluvial erosion is dominant it is important to understand how the 'rain dial' used in a landscape evolution model (LEM) corresponds to real precipitation patterns. One issue with the parameterisation of rainfall for use in an LEM is the difference between the timescales for precipitation (≤ 1 year) and landscape evolution (> 103 years). As a result, precipitation patterns must be upscaled before being integrated into a model. The relevant question then becomes: What is the most appropriate measure of precipitation on a millennial timescale? Previous work (Tucker and Bras, 2000; Lague, 2005) has shown that precipitation can be properly upscaled by taking into account its variable nature, along with its average magnitude. This captures the relative size and frequency of extreme events, ensuring a more accurate characterisation of the integrated effects of precipitation on erosion over long periods of time. In light of this work, we present a statistical parameterisation that accurately models the mean and daily variability of ground based (APHRODITE) and remotely sensed (TRMM) precipitation data in the Himalayan orogen with only a few

  5. Acute exposure to a sublethal dose of imidacloprid and coumaphos enhances olfactory learning and memory in the honeybee Apis mellifera.

    Science.gov (United States)

    Williamson, Sally M; Baker, Daniel D; Wright, Geraldine A

    2013-06-01

    The decline of honeybees and other pollinating insects is a current cause for concern. A major factor implicated in their decline is exposure to agricultural chemicals, in particular the neonicotinoid insecticides such as imidacloprid. Honeybees are also subjected to additional chemical exposure when beekeepers treat hives with acaricides to combat the mite Varroa destructor. Here, we assess the effects of acute sublethal doses of the neonicotinoid imidacloprid, and the organophosphate acaricide coumaphos, on honey bee learning and memory. Imidacloprid had little effect on performance in a six-trial olfactory conditioning assay, while coumaphos caused a modest impairment. We report a surprising lack of additive adverse effects when both compounds were administered simultaneously, which instead produced a modest improvement in learning and memory.

  6. Safety assessment of sugar dusting treatments by analysis of hygienic behavior in honey bee colonies

    Directory of Open Access Journals (Sweden)

    Stevanovic Jevrosima

    2011-01-01

    Full Text Available The hygienic behavior in honey bees is a dominant natural defense mechanism against brood diseases. In this study, the influence of sugar dusting treatments on hygienic behavior was evaluated in 44 strong honey bee colonies. Three doses of pulverized sugar, 20, 30 and 40 g, each applied at three-, seven- and fourteen-day intervals were tested. The percentage of cleaned cells (PCC in the total number of those with pin-killed brood served as a measure of the hygienic potential. The effect was dependent on the frequency of treatments: all doses applied every third and seventh day significantly (p<0.001 decreased the PCC in comparison with the untreated control colonies. Nevertheless, sugar did not threaten the hygienic potential, as PPC values remained above 94% following all treatments. Thus, it can be concluded that the tested sugar treatments are safe and can be justifiably implemented into integrated pest management strategies to control Varroa destructor.

  7. Local bumble bee decline linked to recovery of honey bees, drought effects on floral resources.

    Science.gov (United States)

    Thomson, Diane M

    2016-10-01

    Time series of abundances are critical for understanding how abiotic factors and species interactions affect population dynamics, but are rarely linked with experiments and also scarce for bee pollinators. This gap is important given concerns about declines in some bee species. I monitored honey bee (Apis mellifera) and bumble bee (Bombus spp.) foragers in coastal California from 1999, when feral A. mellifera populations were low due to Varroa destructor, until 2014. Apis mellifera increased substantially, except between 2006 and 2011, coinciding with declines in managed populations. Increases in A. mellifera strongly correlated with declines in Bombus and reduced diet overlap between them, suggesting resource competition consistent with past experimental results. Lower Bombus numbers also correlated with diminished floral resources. Declines in floral abundances were associated with drought and reduced spring rainfall. These results illustrate how competition with an introduced species may interact with climate to drive local decline of native pollinators. © 2016 John Wiley & Sons Ltd/CNRS.

  8. Impregnación superficial, con azufre, del hormigón

    Directory of Open Access Journals (Sweden)

    Dutruel, F.

    1979-03-01

    Full Text Available Se puede afirmar que la durabilidad del hormigón está principalmente condicionada a su compacidad y a su aislamiento de los ambientes agresivos. Los agentes destructores endógenos se consideran eliminados cuando el hormigón está preparado correctamente, con materiales durables y técnica perfecta de amasado, colocación y curado. El centro francés, de estudios e investigaciones de la industria del hormigón "manufacturado" ha emprendido un estudio experimental de la impregnación con azufre. El principal objetivo ha sido comprobar la persistencia, a largo plazo, de las mejoras que se alcanzan en las propiedades físicas y químicas del hormigón por el revestimiento, o mejor, impregnación a cierta profundidad con azufre.

  9. Schedulability Analysis for Java Finalizers

    DEFF Research Database (Denmark)

    Bøgholm, Thomas; Hansen, Rene Rydhof; Søndergaard, Hans

    2010-01-01

    Java finalizers perform clean-up and finalisation of objects at garbage collection time. In real-time Java profiles the use of finalizers is either discouraged (RTSJ, Ravenscar Java) or even disallowed (JSR-302), mainly because of the unpredictability of finalizers and in particular their impact...... on the schedulability analysis. In this paper we show that a controlled scoped memory model results in a structured and predictable execution of finalizers, more reminiscent of C++ destructors than Java finalizers. Furthermore, we incorporate finalizers into a (conservative) schedulability analysis for Predictable Java...... programs. Finally, we extend the SARTS tool for automated schedulability analysis of Java bytecode programs to handle finalizers in a fully automated way....

  10. [Aerobic methylobacteria as the basis for a biosensor for dichloromethane detection].

    Science.gov (United States)

    Plekhanova, Iu V; Firsova, Iu E; Doronina, N V; Trotsenko, Iu A; Reshetilov, A N

    2013-01-01

    Cells of dichloromethane (DChM) bacteria-destructors were immobilized by sorption on different types of membranes, which were fixed on the measuring surface of a pH-sensitive field transistor. The presence of DChM in the medium (0.6-8.8 mM) led to a change in the transistor's output signal, which was determined by the appearance of H+ ions in the medium due to DChM utilization by methylobateria. Among four strains of methylobacteria--Methylobacterium dichloromethanicum DM4, Methylobacterium extorquens DM 17, Methylopila helvetica DM6, and Ancylobacter dichloromethanicus DM 16--the highest and most stable activity toward DChM degradation was observed in the strain M. dichloromethanicum DM4. Among 11 types of membranes for cell immobilization, Millipore nitrocellulose membranes and chromatographic fiber paper GF/A, which allow one to obtain stable biosensor signals for 2 weeks without a bioreceptor change, were chosen as optimal carriers.

  11. EFFICACY OF 15% FORMIC ACID ON VARROA MITES IN DIFFERENT FORMS OF APPLICATION

    Directory of Open Access Journals (Sweden)

    M MUŽA

    2002-05-01

    Full Text Available Varroa destructor is a parasitic mite of the honeybee, Apis mellifera, responsible for reduced honey and brood production, higher bee mortality in winter. Because the resistance to the acaricides and they residues to bee products, alternative products and methods have been used against Varroa. One of this methods is treatment with formic acid. Formic acid induce to Varroa mite in brood and do not leave any residues in products. Concentric formic acid (60-85% is very effective, but at higher air temperature, it has influence on bee. In the last few years, except concentric formic acid, 15 % formic acid was recommended as control of varroosis. Diluted formic acid (15% reduced the bee response to treatment. In treatment with 15% formic acid, higher air temperature and different forms of application have positive influence to they function (65 – 95%.

  12. [The interaction of soil micromycetes with "hot" particles in a model system].

    Science.gov (United States)

    Zhdanova, N N; Lashko, T N; Redchits, T I; Vasilevskaia, A I; Borisiuk, L G; Siniavskaia, O I; Gavriliuk, V I; Muzalev, P N

    1991-01-01

    A model system which permits observing for a long time and fixing interaction of fungi with a radiation source has been created on the basis of an isolated "hot" particle, deficient mineral medium (saccharose content 60 mg/l) and suspension of fungal conidia. Five species (six strains) of micromycetes isolated from radionuclide-contaminated soils and fifteen "hot" particles have been tested. It has been found out for the first time that Cladosporium cladosporioides and Penicillium roseo-purpureum are able actively overgrow "hot" particles whose radioactivity did not exceed 3.1-1.0(-7) Ci by gamma-spectrum and to destroy them 50-150 days later. Certain changes in morphology of fungi-destructors of "hot" particles are revealed. A problem on ecological significance of the found phenomenon is discussed.

  13. Museum samples reveal rapid evolution by wild honey bees exposed to a novel parasite

    Science.gov (United States)

    Mikheyev, Alexander S.; Tin, Mandy M. Y.; Arora, Jatin; Seeley, Thomas D.

    2015-01-01

    Understanding genetic changes caused by novel pathogens and parasites can reveal mechanisms of adaptation and genetic robustness. Using whole-genome sequencing of museum and modern specimens, we describe the genomic changes in a wild population of honey bees in North America following the introduction of the ectoparasitic mite, Varroa destructor. Even though colony density in the study population is the same today as in the past, a major loss of haplotypic diversity occurred, indicative of a drastic mitochondrial bottleneck, caused by massive colony mortality. In contrast, nuclear genetic diversity did not change, though hundreds of genes show signs of selection. The genetic diversity within each bee colony, particularly as a consequence of polyandry by queens, may enable preservation of genetic diversity even during population bottlenecks. These findings suggest that genetically diverse honey bee populations can recover from introduced diseases by evolving rapid tolerance, while maintaining much of the standing genetic variation. PMID:26246313

  14. Museum samples reveal rapid evolution by wild honey bees exposed to a novel parasite.

    Science.gov (United States)

    Mikheyev, Alexander S; Tin, Mandy M Y; Arora, Jatin; Seeley, Thomas D

    2015-08-06

    Understanding genetic changes caused by novel pathogens and parasites can reveal mechanisms of adaptation and genetic robustness. Using whole-genome sequencing of museum and modern specimens, we describe the genomic changes in a wild population of honey bees in North America following the introduction of the ectoparasitic mite, Varroa destructor. Even though colony density in the study population is the same today as in the past, a major loss of haplotypic diversity occurred, indicative of a drastic mitochondrial bottleneck, caused by massive colony mortality. In contrast, nuclear genetic diversity did not change, though hundreds of genes show signs of selection. The genetic diversity within each bee colony, particularly as a consequence of polyandry by queens, may enable preservation of genetic diversity even during population bottlenecks. These findings suggest that genetically diverse honey bee populations can recover from introduced diseases by evolving rapid tolerance, while maintaining much of the standing genetic variation.

  15. Octanoic acid confers to royal jelly varroa-repellent properties

    Science.gov (United States)

    Nazzi, Francesco; Bortolomeazzi, Renzo; Della Vedova, Giorgio; Del Piccolo, Fabio; Annoscia, Desiderato; Milani, Norberto

    2009-02-01

    The mite Varroa destructor Anderson & Trueman is a parasite of the honeybee Apis mellifera L. and represents a major threat for apiculture in the Western world. Reproduction takes place only inside bee brood cells that are invaded just before sealing; drone cells are preferred over worker cells, whereas queen cells are not normally invaded. Lower incidence of mites in queen cells is at least partly due to the deterrent activity of royal jelly. In this study, the repellent properties of royal jelly were investigated using a lab bioassay. Chemical analysis showed that octanoic acid is a major volatile component of royal jelly; by contrast, the concentration is much lower in drone and worker larval food. Bioassays, carried out under lab conditions, demonstrated that octanoic acid is repellent to the mite. Field studies in bee colonies confirmed that the compound may interfere with the process of cell invasion by the mite.

  16. Exogenous Salicylic Acid Enhances the Resistance of Wheat Seedlings to Hessian Fly (Diptera: Cecidomyiidae) Infestation Under Heat Stress.

    Science.gov (United States)

    Underwood, Joshua; Moch, John; Chen, Ming-Shun; Zhu, Lieceng

    2014-10-01

    Heat stress exerts significant impact on plant-parasite interactions. Phytohormones, such as salicylic acid (SA), play important roles in plant defense against parasite attacks. Here, we studied the impact of a combination of heat stress and exogenous SA on the resistance of wheat (Triticum aestivum L.) plants to the Hessian fly [Mayetiola destructor (Say)]. We found that the wheat cultivar 'Molly', which contains the resistance gene H13, lost resistance to Hessian fly under heat stress (40°C for 3 and 6 h), and that exogenous application of SA on Molly seedlings right before heat stress can partially prevent the loss of resistance of Molly plants under heat conditions. Our findings have significant implications for understanding the dynamics of plant-insect interactions in the context of heat stress. © 2014 Entomological Society of America.

  17. Microbiological activities in a shallow-ground repository with cementitious wasteform

    International Nuclear Information System (INIS)

    Varlakova, G.A.; Dyakonova, A.T.; Netrusov, A.I.; Ojovan, M.I.

    2012-01-01

    Cementitious wasteform with immobilised nuclear power plant operational radioactive waste disposed in a near surface testing repository for about 20 years have been analysed for microbiological activities. Clean cultures were selected from the main metabolic groups expected within repository environment e.g. anaerobic de-nitrifying, fermenting, sulphur-reducing, iron-reducing, and oxidizing, thio-bacterium and mushrooms. Microbiological species were identified within cementitious wasteform, in the clayey soil near the wasteform and in the contacting water. The most populated medium was the soil with microbial populations Bacillus, Pseudomonas and Micrococcus, and densities of populations up to 3.6*10 5 colony/g. Microbial populations of generic type Bacillus, Pseudomonas, Rhodococcus, Alcaligenes, Micrococcus, Mycobacterium, and Arthrobacter were identified within cementitious wasteform. Populations of Arthrobacter, Pseudomonas, Alcaligenes, Rhodococcus, Bacillus and Flavobacterium were identified in the water samples contacting the cementitious wasteform. Microbiological species identified are potential destructors of cementitious wasteform and containers. (authors)

  18. Tyramine functions as a toxin in honey bee larvae during Varroa-transmitted infection by Melissococcus pluton.

    Science.gov (United States)

    Kanbar, G; Engels, W; Nicholson, G J; Hertle, R; Winkelmann, G

    2004-05-01

    From wounds of honey bee pupae, caused by the mite Varroa destructor, coccoid bacteria were isolated and identified as Melissococcus pluton. The bacterial isolate was grown anaerobically in sorbitol medium to produce a toxic compound that was purified on XAD columns, gelfiltration and preparative HPLC. The toxic agent was identified by GC-MS and FTICR-MS as tyramine. The toxicity of the isolated tyramine was tested by a novel mobility test using the protozoon Stylonychia lemnae. A concentration of 0.2 mg/ml led to immediate inhibition of mobility. In addition the toxicity was studied on honey bee larvae by feeding tyramine/water mixtures added to the larval jelly. The lethal dosis of tyramine on 4-5 days old bee larvae was determined as 0.3 mg/larvae when added as a volume of 20 microl to the larval food in brood cells. Several other biogenic amines, such as phenylethylamine, histamine, spermine, cadaverine, putrescine and trimethylamine, were tested as their hydrochloric salts for comparison and were found to be inhibitory in the Stylonychia mobility test at similar concentrations. A quantitative hemolysis test with human red blood cells revealed that tyramine and histamine showed the highest membranolytic activity, followed by the phenylethylamine, trimethylamine and spermine, while the linear diamines, cadaverine and putrescine, showed a significantly lower hemolysis when calculated on a molar amine basis. The results indicate that tyramine which is a characteristic amine produced by M. pluton in culture, is the causative agent of the observed toxic symptoms in bee larvae. Thus this disease, known as European foulbrood, is possibly an infection transmitted by the Varroa destructor mite.

  19. The Honey Bee Pathosphere of Mongolia: European Viruses in Central Asia.

    Science.gov (United States)

    Tsevegmid, Khaliunaa; Neumann, Peter; Yañez, Orlando

    2016-01-01

    Parasites and pathogens are apparent key factors for the detrimental health of managed European honey bee subspecies, Apis mellifera. Apicultural trade is arguably the main factor for the almost global distribution of most honey bee diseases, thereby increasing chances for multiple infestations/infections of regions, apiaries, colonies and even individual bees. This imposes difficulties to evaluate the effects of pathogens in isolation, thereby creating demand to survey remote areas. Here, we conducted the first comprehensive survey for 14 honey bee pathogens in Mongolia (N = 3 regions, N = 9 locations, N = 151 colonies), where honey bee colonies depend on humans to overwinter. In Mongolia, honey bees, Apis spp., are not native and colonies of European A. mellifera subspecies have been introduced ~60 years ago. Despite the high detection power and large sample size across Mongolian regions with beekeeping, the mite Acarapis woodi, the bacteria Melissococcus plutonius and Paenibacillus larvae, the microsporidian Nosema apis, Acute bee paralysis virus, Kashmir bee virus, Israeli acute paralysis virus and Lake Sinai virus strain 2 were not detected, suggesting that they are either very rare or absent. The mite Varroa destructor, Nosema ceranae and four viruses (Sacbrood virus, Black queen cell virus, Deformed wing virus (DWV) and Chronic bee paralysis virus) were found with different prevalence. Despite the positive correlation between the prevalence of V. destructor mites and DWV, some areas had only mites, but not DWV, which is most likely due to the exceptional isolation of apiaries (up to 600 km). Phylogenetic analyses of the detected viruses reveal their clustering and European origin, thereby supporting the role of trade for pathogen spread and the isolation of Mongolia from South-Asian countries. In conclusion, this survey reveals the distinctive honey bee pathosphere of Mongolia, which offers opportunities for exciting future research.

  20. Use of tritium-labeled PCBs for investigation of PCBs biodegradation by soil bacteria

    International Nuclear Information System (INIS)

    Kim, A.A.; Djuraeva, G.T.; Takhtobiri, K.S.; Yadgarov, H.T.; Zinovev, P. V.; Abdukarimov, A.A.

    2002-01-01

    The method for tritium labelling of polychlorinated biphenyls (PCBs) was developed. The strains of soil bacteria - destructors of chloro organic compounds was studied with the help of test-system based on the using of tritium-labeled PCBs. The strains of bacteria were grown on the agar synthetic medium and then were introduced into the synthetic medium containing tritium-labeled mixture of PCBs (commercial mark - SOVOL) as alone source of carbon. The samples were analysed after one and two months period of incubation. PCBs were extracted by hexane from fraction of bacteria and fraction of cultural medium and radioactivity was measured. The samples were analyzed by thin layer chromatography (TLC) with following radioautography. Additionally samples were analyzed by gas chromatography. It was found that all selected strains survived in the medium with PCBs as alone source of carbon and bacteria accumulated PCBs from cultural medium. Accumulation of PCBs by strains of bacteria was different. The TLC analysis detected additional compounds labeled by tritium, that prove the degradation of PCBs in presence of bacteria. The gas chromatography analysis of cultural medium and bacteria detected redistribution in the system and qualitative changes of PCBs in bacteria. The strains of bacteria also were grown in model condition on the soil with tritium labeled PCBs. We found that some strains effectively destroy PCBs with decreasing level of tritium label in the soil. The using of tritium labeled PCBs' allows to introduce precise quantitative characteristics for study of accumulation and biodegradation PCBs by soil bacteria strains. Developed test-system is very useful tool for selection of new strains of soil bacteria - destructors of PCBs

  1. Recognition of mite-infested brood by honeybee (Apis mellifera) workers may involve thermal sensing.

    Science.gov (United States)

    Bauer, Daniel; Wegener, Jakob; Bienefeld, Kaspar

    2018-05-01

    Hygienic behavior, i.e. the removal of diseased or damaged brood by worker honey bees (Apis mellifera), is seen as one of the principal behavioral elements of this species' social immunity. Identification of the stimuli that trigger it would be helpful in searching for biochemical and molecular markers of this important breeding trait. While many studies at the genomic, transcriptomic, and behavioral level have pointed to the implication of chemical cues, we here hypothesized that thermal cues are alternatively/additionally involved. To test this hypothesis, we first measured whether infestation by the mite Varroa destructor (a condition known to induce hygienic behavior) leads to a thermal gradient between affected and unaffected brood. We found that infested brood cells were between 0.03 and 0.19 °C warmer than uninfested controls. Next, we tested whether artificially heating an area of a brood comb would increase the removal of infested or uninfested brood as compared to an unheated control area, and found that this was not the case. Finally, we investigated whether the heating of individual brood cells, as opposed to comb areas, would influence brood removal from cells adjacent to the heated one. This was the case for uninfested, though not for infested cells. We conclude that infestation by V. destructor leads to a heating of brood cells that should be perceivable by bees, and that small-scale temperature gradients can influence brood removal. This makes it appear possible that thermal cues play a role in triggering hygienic behavior of honey bees directed at varroa-infested larvae/pupae, although our results are insufficient to prove such an involvement. Copyright © 2018. Published by Elsevier Ltd.

  2. Honey Bee Colonies Headed by Hyperpolyandrous Queens Have Improved Brood Rearing Efficiency and Lower Infestation Rates of Parasitic Varroa Mites.

    Directory of Open Access Journals (Sweden)

    Keith S Delaplane

    Full Text Available A honey bee queen mates on wing with an average of 12 males and stores their sperm to produce progeny of mixed paternity. The degree of a queen's polyandry is positively associated with measures of her colony's fitness, and observed distributions of mating number are evolutionary optima balancing risks of mating flights against benefits to the colony. Effective mating numbers as high as 40 have been documented, begging the question of the upper bounds of this behavior that can be expected to confer colony benefit. In this study we used instrumental insemination to create three classes of queens with exaggerated range of polyandry--15, 30, or 60 drones. Colonies headed by queens inseminated with 30 or 60 drones produced more brood per bee and had a lower proportion of samples positive for Varroa destructor mites than colonies whose queens were inseminated with 15 drones, suggesting benefits of polyandry at rates higher than those normally obtaining in nature. Our results are consistent with two hypotheses that posit conditions that reward such high expressions of polyandry: (1 a queen may mate with many males in order to promote beneficial non-additive genetic interactions among subfamilies, and (2 a queen may mate with many males in order to capture a large number of rare alleles that regulate resistance to pathogens and parasites in a breeding population. Our results are unique for identifying the highest levels of polyandry yet detected that confer colony-level benefit and for showing a benefit of polyandry in particular toward the parasitic mite V. destructor.

  3. Virus Status, Varroa Levels, and Survival of 20 Managed Honey Bee Colonies Monitored in Luxembourg Between the Summer of 2011 and the Spring of 2013

    Directory of Open Access Journals (Sweden)

    Clermont Antoine

    2015-06-01

    Full Text Available Twenty managed honey bee colonies, split between 5 apiaries with 4 hives each, were monitored between the summer of 2011 and spring of 2013. Living bees were sampled in July 2011, July 2012, and August 2012. Twenty-five, medium-aged bees, free of varroa mites, were pooled per colony and date, to form one sample. Unlike in France and Belgium, Chronic Bee Paralysis Virus (CBPV has not been found in Luxembourg. Slow Bee Paralysis Virus (SBPV and Israeli Acute Paralysis Virus (IAPV levels were below detection limits. Traces of Kashmir Bee Virus (KBV were amplified. Black Queen Cell Virus (BQCV, Varroa destructor Virus-1 (VDV-1, and SacBrood Virus (SBV were detected in all samples and are reported from Luxembourg for the first time. Varroa destructor Macula- Like Virus (VdMLV, Deformed Wing Virus (DWV, and Acute Bee Paralysis Virus (ABPV were detected at all locations, and in most but not all samples. There was a significant increase in VDV-1 and DWV levels within the observation period. A principal component analysis was unable to separate the bees of colonies that survived the following winter from bees that died, based on their virus contents in summer. The number of dead varroa mites found below colonies was elevated in colonies that died in the following winter. Significant positive relationships were found between the log-transformed virus levels of the bees and the log-transformed number of mites found below the colonies per week, for VDV-1 and DWV. Sacbrood virus levels were independent of varroa levels, suggesting a neutral or competitive relationship between this virus and varroa.

  4. Development of a 44K SNP assay focussing on the analysis of a varroa-specific defence behaviour in honey bees (Apis mellifera carnica).

    Science.gov (United States)

    Spötter, A; Gupta, P; Nürnberg, G; Reinsch, N; Bienefeld, K

    2012-03-01

    Honey bees are exposed to a number of damaging pathogens and parasites. The most destructive among them, affecting mainly the brood, is Varroa destructor. A promising approach to prevent its spread is to breed for Varroa-tolerant honey bees. A trait that has been shown to provide significant resistance against the Varroa mite is hygienic behaviour, a behavioural response of honey bee workers to brood diseases in general. This study reports the development of a 44K SNP assay, specifically designed for the analysis of hygienic behaviour of individual worker bees (Apis mellifera carnica) directed against V. destructor. Initially, 70,000 SNPs chosen from a large set of SNPs published by the Honey Bee Genome Project were validated for their suitability in the analysis of the Varroa resistance trait 'uncapping of Varroa-infested brood'. This was achieved by genotyping of pooled DNA samples of trait bearers and two trait-negative controls using next-generation sequencing. Approximately 36,000 of these validated SNPs and another 8000 SNPs not validated in this study were selected for the construction of a SNP assay. This assay will be employed in following experiments to analyse individualized DNA samples in order to identify quantitative trait loci (QTL) involved in the control of the investigated trait and to evaluate and possibly confirm QTL found in other studies. However, this assay is not just suitable to study Varroa tolerance, it is as well applicable to analyse any other trait in honey bees. In addition, because of its high density, this assay provides access into genomic selection with respect to several traits considered in honey bee breeding. It will become publicly available via AROS Applied Biotechnology AS, Aarhus, Denmark, before the end of the year 2011. © 2011 Blackwell Publishing Ltd.

  5. Impacts of Austrian Climate Variability on Honey Bee Mortality

    Science.gov (United States)

    Switanek, Matt; Brodschneider, Robert; Crailsheim, Karl; Truhetz, Heimo

    2015-04-01

    Global food production, as it is today, is not possible without pollinators such as the honey bee. It is therefore alarming that honey bee populations across the world have seen increased mortality rates in the last few decades. The challenges facing the honey bee calls into question the future of our food supply. Beside various infectious diseases, Varroa destructor is one of the main culprits leading to increased rates of honey bee mortality. Varroa destructor is a parasitic mite which strongly depends on honey bee brood for reproduction and can wipe out entire colonies. However, climate variability may also importantly influence honey bee breeding cycles and bee mortality rates. Persistent weather events affects vegetation and hence foraging possibilities for honey bees. This study first defines critical statistical relationships between key climate indicators (e.g., precipitation and temperature) and bee mortality rates across Austria, using 6 consecutive years of data. Next, these leading indicators, as they vary in space and time, are used to build a statistical model to predict bee mortality rates and the respective number of colonies affected. Using leave-one-out cross validation, the model reduces the Root Mean Square Error (RMSE) by 21% with respect to predictions made with the mean mortality rate and the number of colonies. Furthermore, a Monte Carlo test is used to establish that the model's predictions are statistically significant at the 99.9% confidence level. These results highlight the influence of climate variables on honey bee populations, although variability in climate, by itself, cannot fully explain colony losses. This study was funded by the Austrian project 'Zukunft Biene'.

  6. The Honey Bee Pathosphere of Mongolia: European Viruses in Central Asia.

    Directory of Open Access Journals (Sweden)

    Khaliunaa Tsevegmid

    Full Text Available Parasites and pathogens are apparent key factors for the detrimental health of managed European honey bee subspecies, Apis mellifera. Apicultural trade is arguably the main factor for the almost global distribution of most honey bee diseases, thereby increasing chances for multiple infestations/infections of regions, apiaries, colonies and even individual bees. This imposes difficulties to evaluate the effects of pathogens in isolation, thereby creating demand to survey remote areas. Here, we conducted the first comprehensive survey for 14 honey bee pathogens in Mongolia (N = 3 regions, N = 9 locations, N = 151 colonies, where honey bee colonies depend on humans to overwinter. In Mongolia, honey bees, Apis spp., are not native and colonies of European A. mellifera subspecies have been introduced ~60 years ago. Despite the high detection power and large sample size across Mongolian regions with beekeeping, the mite Acarapis woodi, the bacteria Melissococcus plutonius and Paenibacillus larvae, the microsporidian Nosema apis, Acute bee paralysis virus, Kashmir bee virus, Israeli acute paralysis virus and Lake Sinai virus strain 2 were not detected, suggesting that they are either very rare or absent. The mite Varroa destructor, Nosema ceranae and four viruses (Sacbrood virus, Black queen cell virus, Deformed wing virus (DWV and Chronic bee paralysis virus were found with different prevalence. Despite the positive correlation between the prevalence of V. destructor mites and DWV, some areas had only mites, but not DWV, which is most likely due to the exceptional isolation of apiaries (up to 600 km. Phylogenetic analyses of the detected viruses reveal their clustering and European origin, thereby supporting the role of trade for pathogen spread and the isolation of Mongolia from South-Asian countries. In conclusion, this survey reveals the distinctive honey bee pathosphere of Mongolia, which offers opportunities for exciting future research.

  7. Differential Gene Expression Associated with Honey Bee Grooming Behavior in Response to Varroa Mites.

    Science.gov (United States)

    Hamiduzzaman, Mollah Md; Emsen, Berna; Hunt, Greg J; Subramanyam, Subhashree; Williams, Christie E; Tsuruda, Jennifer M; Guzman-Novoa, Ernesto

    2017-05-01

    Honey bee (Apis mellifera) grooming behavior is an important mechanism of resistance against the parasitic mite Varroa destructor. This research was conducted to study associations between grooming behavior and the expression of selected immune, neural, detoxification, developmental and health-related genes. Individual bees tested in a laboratory assay for various levels of grooming behavior in response to V. destructor were also analyzed for gene expression. Intense groomers (IG) were most efficient in that they needed significantly less time to start grooming and fewer grooming attempts to successfully remove mites from their bodies than did light groomers (LG). In addition, the relative abundance of the neurexin-1 mRNA, was significantly higher in IG than in LG, no groomers (NG) or control (bees without mite). The abundance of poly U binding factor kd 68 and cytochrome p450 mRNAs were significantly higher in IG than in control bees. The abundance of hymenoptaecin mRNA was significantly higher in IG than in NG, but it was not different from that of control bees. The abundance of vitellogenin mRNA was not changed by grooming activity. However, the abundance of blue cheese mRNA was significantly reduced in IG compared to LG or NG, but not to control bees. Efficient removal of mites by IG correlated with different gene expression patterns in bees. These results suggest that the level of grooming behavior may be related to the expression pattern of vital honey bee genes. Neurexin-1, in particular, might be useful as a bio-marker for behavioral traits in bees.

  8. Undergraduate Convexity

    DEFF Research Database (Denmark)

    Lauritzen, Niels

    Based on undergraduate teaching to students in computer science, economics and mathematics at Aarhus University, this is an elementary introduction to convex sets and convex functions with emphasis on concrete computations and examples. Starting from linear inequalities and Fourier-Motzkin elimin......Based on undergraduate teaching to students in computer science, economics and mathematics at Aarhus University, this is an elementary introduction to convex sets and convex functions with emphasis on concrete computations and examples. Starting from linear inequalities and Fourier......-Motzkin elimination, the theory is developed by introducing polyhedra, the double description method and the simplex algorithm, closed convex subsets, convex functions of one and several variables ending with a chapter on convex optimization with the Karush-Kuhn-Tucker conditions, duality and an interior point...... algorithm....

  9. Molecular neuroeconomics of crime and punishment: implications for neurolaw.

    Science.gov (United States)

    Takahashi, Taiki

    2012-01-01

    Criminal behaviors have been associated with risk, time and social preferences in economics (Becker 1968; Davis 1988), criminology (Chamlin & Cochran 1997), and neurolaw (Goodenough & Tucker 2010). This study proposes a molecular neuroeconomic framework for the investigation into crime and punishment. Neuroeconomic parameters (e.g., risk-attitude, probability weighting, time discounting in intertemporal choice, loss aversion, and social discounting) are predicted to be related to criminal behavior. Neurobiological and neuroendocrinological substrates such as serotonin, dopamine, norepinephrine, cortisol (a stress hormone), sex hormones (e.g., testosterone), and oxytocin in brain regions such as the orbitofrontal cortex, the amygdala, and the cingulate may be related to the neuroeconomic parameters governing criminal behaviors. The present framework may help us develop "neurolaw" based on molecular neuroeconomics of criminal and antisocial decision-making processes.

  10. Emotion Management in Small Hotels: Meeting the Challenges of Flexibility and Informality

    Directory of Open Access Journals (Sweden)

    Anne Benmore

    2014-12-01

    Full Text Available This paper shows that in small hotels, hotel owners interpret "hospitality‟ more broadly than mere commercial concerns. Hoteliers engage with three interdependent hospitality domains, commercial, social and private (Lashley, 2000, an approach that enables them to perceive guest interactions as informal; characterised by hoteliers wanting to "know‟ and "relate to‟ their guests. The findings here, drawn from a study of small hotels in the UK, show how owners manage this form of the "host-guest relationship‟ (Tucker, 2003 by employing a range of emotion management strategies. These mirror Bolton‟s 4Ps framework (2009 of pecuniary, professional, presentational and philanthropic emotion management roles. Adopting this fluid approach, rather than relying on emotional labour (Hochschild, 1983, enables the hoteliers to respond flexibly to meet the needs of their different types of guest. The findings in this paper validate Bolton's argument (2005 for using agential flexible emotion management that captures but goes beyond emotional labour.

  11. Optimisasi Portofolio Mean-VaR di bawah CAPM Transformasi Koyck dengan Volatilitas Tak Konstan dan Efek Long Memory

    Directory of Open Access Journals (Sweden)

    Sukono Sukono

    2010-01-01

    Full Text Available In this paper we formulated mean-VaR portfolio optimization through CAPM Koyck transformation. We assumed that lagged of risk premium which have highly influence on stock returns is infinite, while model parameters decrease geometrically. We also assumed that rate of return in risk premium market index is not constant, in other word has a non-constant volatility rate, and also has a long memory effect. The later was analyzed using ARFIMA. Non constant volatility rate was modeled via GARCH model. The portfolio optimization was constructed using Langrangian multiplier and the Kuhn-Tucker theorem was employed to obtain the solution by the least square method. Finally, we provide a numerical example of the optimization model based on several stocks traded in Indonesian capital market.

  12. A Modified Levenberg-Marquardt Method for Nonsmooth Equations with Finitely Many Maximum Functions

    Directory of Open Access Journals (Sweden)

    Shou-qiang Du

    2008-01-01

    Full Text Available For solving nonsmooth systems of equations, the Levenberg-Marquardt method and its variants are of particular importance because of their locally fast convergent rates. Finitely many maximum functions systems are very useful in the study of nonlinear complementarity problems, variational inequality problems, Karush-Kuhn-Tucker systems of nonlinear programming problems, and many problems in mechanics and engineering. In this paper, we present a modified Levenberg-Marquardt method for nonsmooth equations with finitely many maximum functions. Under mild assumptions, the present method is shown to be convergent Q-linearly. Some numerical results comparing the proposed method with classical reformulations indicate that the modified Levenberg-Marquardt algorithm works quite well in practice.

  13. A Constrained Algorithm Based NMFα for Image Representation

    Directory of Open Access Journals (Sweden)

    Chenxue Yang

    2014-01-01

    Full Text Available Nonnegative matrix factorization (NMF is a useful tool in learning a basic representation of image data. However, its performance and applicability in real scenarios are limited because of the lack of image information. In this paper, we propose a constrained matrix decomposition algorithm for image representation which contains parameters associated with the characteristics of image data sets. Particularly, we impose label information as additional hard constraints to the α-divergence-NMF unsupervised learning algorithm. The resulted algorithm is derived by using Karush-Kuhn-Tucker (KKT conditions as well as the projected gradient and its monotonic local convergence is proved by using auxiliary functions. In addition, we provide a method to select the parameters to our semisupervised matrix decomposition algorithm in the experiment. Compared with the state-of-the-art approaches, our method with the parameters has the best classification accuracy on three image data sets.

  14. Adventive plants from ovules and nucelli in Citrus.

    Science.gov (United States)

    Kochba, J; Spiegel-Roy, P; Safran, H

    1972-09-01

    1- to 8-week-old ovules and nucelli from three Citrus cultivars-Shamouti and Valencia (Citrus sinensis) oranges and Marsh Seedless (C. paradisi) grapefruit-were cultured in vitro. No embryo differentiation was observed in the explants prior to culture. The Shamouti ovules had degenerated and were apparently unfertilized. Embryoids formed on Murashige and Tucker nutrient medium supplemented with 500 mg/l malt extract. Whole plants developed on the same basal medium supplemented with kinetin and indole-3-acetic acid (IAA), coconut milk or gibberellic acid (GA3). A higher kinetin/IAA ratio or the addition of coconut milk favoured stem elongation more than root formation while a lower kinetin/IAA ratio favoured root formation and inhibited stem elongation. The addition of GA3 to the basal medium stimulated rooting and stem elongation. These results can be of aid in mutation research, allowing irradiation at stages prior to embryonic development.

  15. Two-dimensional strain gradient damage modeling: a variational approach

    Science.gov (United States)

    Placidi, Luca; Misra, Anil; Barchiesi, Emilio

    2018-06-01

    In this paper, we formulate a linear elastic second gradient isotropic two-dimensional continuum model accounting for irreversible damage. The failure is defined as the condition in which the damage parameter reaches 1, at least in one point of the domain. The quasi-static approximation is done, i.e., the kinetic energy is assumed to be negligible. In order to deal with dissipation, a damage dissipation term is considered in the deformation energy functional. The key goal of this paper is to apply a non-standard variational procedure to exploit the damage irreversibility argument. As a result, we derive not only the equilibrium equations but, notably, also the Karush-Kuhn-Tucker conditions. Finally, numerical simulations for exemplary problems are discussed as some constitutive parameters are varying, with the inclusion of a mesh-independence evidence. Element-free Galerkin method and moving least square shape functions have been employed.

  16. Targeting human c-Myc promoter duplex DNA with actinomycin D by use of multi-way analysis of quantum-dot-mediated fluorescence resonance energy transfer

    DEFF Research Database (Denmark)

    Gholami, Somayeh; Kompany Zare, Mohsen

    2013-01-01

    Actinomycin D (Act D), an oncogenic c-Myc promoter binder, interferes with the action of RNA polymerase. There is great demand for high-throughput technology able to monitor the activity of DNA-binding drugs. To this end, binding of 7-aminoactinomycin D (7AAD) to the duplex c-Myc promoter...... pairs resulted in efficient energy transfer from drug to QD via fluorescence resonance energy transfer (FRET). Multi-way analysis of the three-way data array obtained from titration experiments was performed by use of restricted Tucker3 and hard trilinear decomposition (HTD). These techniques enable...... the important advantage over univariate classical methods of enabling us to investigate the source of variance in the fluorescence signal of the DNA-drug complex. It was established that hard trilinear decomposition analysis of FRET-measured data overcomes the problem of rank deficiency, enabling calculation...

  17. Taking off the square root of Nambu-Goto action and obtaining Filippov-Lie algebra gauge theory action

    International Nuclear Information System (INIS)

    Park, Jeong-Hyuck; Sochichiu, Corneliu

    2009-01-01

    We propose a novel prescription to take off the square root of the Nambu-Goto action for a p-brane, which generalizes the Brink-Di Vecchia-Howe-Tucker, also known as the Polyakov method. With an arbitrary decomposition, d+n=p+1, our resulting action is a modified d-dimensional Polyakov action, which is gauged and possesses a Nambu n-bracket squared potential. We first spell out how the (p+1)-dimensional diffeomorphism is realized in the lower dimensional action. Then we discuss a possible gauge fixing of it to a direct product of d-dimensional diffeomorphism and n-dimensional volume preserving diffeomorphism. We show that the latter naturally leads to a novel Filippov-Lie n-algebra based gauge theory action in d dimensions. (orig.)

  18. Strategic Maintenance Scheduling of an Offshore Wind Farm in a Deregulated Power System

    Directory of Open Access Journals (Sweden)

    Peyman Mazidi

    2017-03-01

    Full Text Available This paper proposes a model for strategic maintenance scheduling of offshore wind farms (SMSOWF in a deregulated power system. The objective of the model is to plan the maintenance schedules in a way to maximize the profit of the offshore wind farm. In addition, some network constraints, such as transmission lines capacity, and wind farm constraints, such as labor working shift, wave height limit and wake effect, as well as unexpected outages, are included in deterministic and stochastic studies. Moreover, the proposedmodel provides theability to incorporate information from condition monitoring systems. SMSOWF is formulated through a bi-level formulation and then transformed into a single-level through Karush–Kuhn–Tucker conditions. The model is validated through a test system, and the results demonstrate applicability, advantages and challenges of harnessing the full potential of the model.

  19. Geodesic B-Preinvex Functions and Multiobjective Optimization Problems on Riemannian Manifolds

    Directory of Open Access Journals (Sweden)

    Sheng-lan Chen

    2014-01-01

    Full Text Available We introduce a class of functions called geodesic B-preinvex and geodesic B-invex functions on Riemannian manifolds and generalize the notions to the so-called geodesic quasi/pseudo B-preinvex and geodesic quasi/pseudo B-invex functions. We discuss the links among these functions under appropriate conditions and obtain results concerning extremum points of a nonsmooth geodesic B-preinvex function by using the proximal subdifferential. Moreover, we study a differentiable multiobjective optimization problem involving new classes of generalized geodesic B-invex functions and derive Kuhn-Tucker-type sufficient conditions for a feasible point to be an efficient or properly efficient solution. Finally, a Mond-Weir type duality is formulated and some duality results are given for the pair of primal and dual programming.

  20. A superlinear interior points algorithm for engineering design optimization

    Science.gov (United States)

    Herskovits, J.; Asquier, J.

    1990-01-01

    We present a quasi-Newton interior points algorithm for nonlinear constrained optimization. It is based on a general approach consisting of the iterative solution in the primal and dual spaces of the equalities in Karush-Kuhn-Tucker optimality conditions. This is done in such a way to have primal and dual feasibility at each iteration, which ensures satisfaction of those optimality conditions at the limit points. This approach is very strong and efficient, since at each iteration it only requires the solution of two linear systems with the same matrix, instead of quadratic programming subproblems. It is also particularly appropriate for engineering design optimization inasmuch at each iteration a feasible design is obtained. The present algorithm uses a quasi-Newton approximation of the second derivative of the Lagrangian function in order to have superlinear asymptotic convergence. We discuss theoretical aspects of the algorithm and its computer implementation.

  1. Characterization of the damage produced on different materials surfaces

    International Nuclear Information System (INIS)

    Dellavale Clara, Hector Damian

    2004-01-01

    In the present work the characterization techniques of surfaces ULOI and RIMAPS have been applied on laboratory samples made from aluminium, stainless steel and material based on fiberglass.The resultant surfaces of, chemical etching with corrosive agents Keller and Tucker, mechanic damage from the wear and tear of abrasive paper and sandrubbing with alumina particles, are analyzed to different level of damage.The systematic application of the above mentioned techniques is carried out with the objective of finding information, which allows to characterize the superficial damage, both in its incipient state as in the extreme situation revealed by the presence of etch pits. Important results have been obtained, in the characterization of the incipient stage of the chemical etching, using the curves of the normalized area.In addition, it was possible to verify the capacity of the techniques in the early detection of the preferential directions generated by the etch pits

  2. Matrix- and tensor-based recommender systems for the discovery of currently unknown inorganic compounds

    Science.gov (United States)

    Seko, Atsuto; Hayashi, Hiroyuki; Kashima, Hisashi; Tanaka, Isao

    2018-01-01

    Chemically relevant compositions (CRCs) and atomic arrangements of inorganic compounds have been collected as inorganic crystal structure databases. Machine learning is a unique approach to search for currently unknown CRCs from vast candidates. Herein we propose matrix- and tensor-based recommender system approaches to predict currently unknown CRCs from database entries of CRCs. Firstly, the performance of the recommender system approaches to discover currently unknown CRCs is examined. A Tucker decomposition recommender system shows the best discovery rate of CRCs as the majority of the top 100 recommended ternary and quaternary compositions correspond to CRCs. Secondly, systematic density functional theory (DFT) calculations are performed to investigate the phase stability of the recommended compositions. The phase stability of the 27 compositions reveals that 23 currently unknown compounds are newly found to be stable. These results indicate that the recommender system has great potential to accelerate the discovery of new compounds.

  3. Libre Knowledge and another world is possible

    CSIR Research Space (South Africa)

    Tucker, KC

    2007-08-01

    Full Text Available  and Equality Kim Tucker (managed by the CISR in South Africa) presented at Open Education 2007 Localizing and Learning September 26­28, 2007     2http://en.wikipedia.org/wiki/Image:LocationSouthernAfrica.png http://en.wikipedia.org.../wiki/Image:LocationAfrica.png Perspectives Towards collective understanding     3 South Africa a “developing” country / http://en.wikipedia.org/wiki/Image:LocationSouthAfrica.svg http://www.ted.com/talks/view/id/92     4 a world in one country http://en.wikipedia.org...

  4. Source conductance scaling for high frequency superconducting quasiparticle receivers

    Science.gov (United States)

    Ke, Qing; Feldman, M. J.

    1992-01-01

    It has been suggested that the optimum source conductance G(sub s) for the superconductor-insulator-superconductor (SIS) quasiparticle mixer should have a l/f dependence. This would imply that the critical current density of SIS junctions used for mixing should increase as frequency squared, a stringent constraint on the design of submillimeter SIS mixers, rather than in simple proportion to frequency as previously believed. We have used Tucker's quantum theory of mixing for extensive numerical calculations to determine G(sub s) for an optimized SIS receiver. We find that G(sub s) is very roughly independent of frequency (except for the best junctions at low frequency), and discuss the implications of our results for the design of submillimeter SIS mixers.

  5. Determining Bounds on Assumption Errors in Operational Analysis

    Directory of Open Access Journals (Sweden)

    Neal M. Bengtson

    2014-01-01

    Full Text Available The technique of operational analysis (OA is used in the study of systems performance, mainly for estimating mean values of various measures of interest, such as, number of jobs at a device and response times. The basic principles of operational analysis allow errors in assumptions to be quantified over a time period. The assumptions which are used to derive the operational analysis relationships are studied. Using Karush-Kuhn-Tucker (KKT conditions bounds on error measures of these OA relationships are found. Examples of these bounds are used for representative performance measures to show limits on the difference between true performance values and those estimated by operational analysis relationships. A technique for finding tolerance limits on the bounds is demonstrated with a simulation example.

  6. A one-layer recurrent neural network for constrained nonconvex optimization.

    Science.gov (United States)

    Li, Guocheng; Yan, Zheng; Wang, Jun

    2015-01-01

    In this paper, a one-layer recurrent neural network is proposed for solving nonconvex optimization problems subject to general inequality constraints, designed based on an exact penalty function method. It is proved herein that any neuron state of the proposed neural network is convergent to the feasible region in finite time and stays there thereafter, provided that the penalty parameter is sufficiently large. The lower bounds of the penalty parameter and convergence time are also estimated. In addition, any neural state of the proposed neural network is convergent to its equilibrium point set which satisfies the Karush-Kuhn-Tucker conditions of the optimization problem. Moreover, the equilibrium point set is equivalent to the optimal solution to the nonconvex optimization problem if the objective function and constraints satisfy given conditions. Four numerical examples are provided to illustrate the performances of the proposed neural network.

  7. Perceptions and receptivity of non-spousal family support: A mixed methods study of psychological distress among older, church-going African American men.

    Science.gov (United States)

    Watkins, Daphne C; Wharton, Tracy; Mitchell, Jamie A; Matusko, Niki; Kales, Helen

    2017-10-01

    The purpose of this study was to explore the role of non-spousal family support on mental health among older, church-going African American men. The mixed methods objective was to employ a design that used existing qualitative and quantitative data to explore the interpretive context within which social and cultural experiences occur. Qualitative data (n=21) were used to build a conceptual model that was tested using quantitative data (n= 401). Confirmatory factor analysis indicated an inverse association between non-spousal family support and distress. The comparative fit index, Tucker-Lewis fit index, and root mean square error of approximation indicated good model fit. This study offers unique methodological approaches to using existing, complementary data sources to understand the health of African American men.

  8. Numerical Methods for Solution of the Extended Linear Quadratic Control Problem

    DEFF Research Database (Denmark)

    Jørgensen, John Bagterp; Frison, Gianluca; Gade-Nielsen, Nicolai Fog

    2012-01-01

    In this paper we present the extended linear quadratic control problem, its efficient solution, and a discussion of how it arises in the numerical solution of nonlinear model predictive control problems. The extended linear quadratic control problem is the optimal control problem corresponding...... to the Karush-Kuhn-Tucker system that constitute the majority of computational work in constrained nonlinear and linear model predictive control problems solved by efficient MPC-tailored interior-point and active-set algorithms. We state various methods of solving the extended linear quadratic control problem...... and discuss instances in which it arises. The methods discussed in the paper have been implemented in efficient C code for both CPUs and GPUs for a number of test examples....

  9. Spatial distribution and pollution evaluation of heavy metals in Yangtze estuary sediment.

    Science.gov (United States)

    Liu, Ruimin; Men, Cong; Liu, Yongyan; Yu, Wenwen; Xu, Fei; Shen, Zhenyao

    2016-09-15

    To analyze the spatial distribution patterns and ecological risks of heavy metals, 30 sediment samples were taken in the Yangtze River Estuary (YRE) in May 2011. The content of Al, As, Cr, Cu, Fe, Mn, Ni and Pb increased as follows: inner-regionpollutants. What is more, the greatest contaminated area appeared at the river mouth of the south branch of YRE. In Tucker 3, considering the fractions of metals, Mn turned to be the severest pollutant and As did not contribute too much to the contamination of the YRE. That was most probably because that Mn was closely related to the carbonate-associated (CARB) and As was related to organic-associated (OM) which is more stable than CARB. The fractions played an important role in the contamination assessment of heavy metals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Mechanisms of embodiment.

    Science.gov (United States)

    Dijkstra, Katinka; Post, Lysanne

    2015-01-01

    This paper is a critical review of recent studies demonstrating the mechanism of sensorimotor simulation in different cognitive domains. Empirical studies that specify conditions under which embodiment occurs in different domains will be discussed and evaluated. Examples of relevant domains are language comprehension (Tucker and Ellis, 1998), autobiographical memory (Dijkstra et al., 2007), gestures (Alibali et al., 2014), facial mimicry (Stel and Vonk, 2010), and problem solving (Wiemers et al., 2014). The focus of the review is on supporting claims regarding sensorimotor simulation as well as on factors that modulate dynamic relationships between sensorimotor components in action and cognitive domains, such as expertise (Boschker et al., 2002). This discussion takes place within the context of currently debated issues, specifically the need to specify the underlying mechanisms of embodied representations (Zwaan, 2014; Körner et al., 2015).

  11. Antifungal Activity of Bacillus coagulans TQ33, Isolated from Skimmed Milk Powder, against Botrytis cinerea

    Directory of Open Access Journals (Sweden)

    Rui Feng Xiao

    2013-01-01

    Full Text Available Bacillus coagulans TQ33 is isolated from the skimmed milk powder and has a broad antifungal activity against pathogens such as Botrytis cinerea, Alternaria solani, Phytophthora drechsleri Tucker, Fusarium oxysporum and Glomerella cingulata. The characteristics of active antifungal substances produced by B. coagulans TQ33 and its antifungal effects against the growth of plant pathogenic fungi has been evaluated. The effect of pH, temperature and protease on the antifungal activity of B. coagulans TQ33 was determined. The results of partial characterization of the antifungal compound indicated that its activity is likely to be due to the production of a proteinaceous substance together with other substances. The greenhouse trials suggest that B. coagulans TQ33 has a great potential for the control of plant pathogenic fungi.

  12. Capacity bounds for parallel IM-DD optical wireless channels

    KAUST Repository

    Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

    2016-01-01

    A system consisting of parallel intensity-modulation direct-detection optical wireless channels with a total average intensity constraint is studied. Capacity upper and lower bounds for this system are derived. If channel-state information is available at the transmitter, the bounds have to be optimized with respect to intensity allocation over the parallel channels. The optimization of the lower bound is non-convex, however, the Karush-Kuhn-Tucker conditions can be used to find a list of possible solutions one of which is optimal. The optimal solution can then be found by an exhaustive search algorithm, which is computationally expensive. To overcome this, we propose a low-complexity intensity allocation algorithm which is nearly optimal. The optimized capacity lower bound coincides with the capacity at high signal-to-noise ratio. © 2016 IEEE.

  13. Mechanisms of embodiment

    Directory of Open Access Journals (Sweden)

    Katinka eDijkstra

    2015-10-01

    Full Text Available This paper is a critical review of recent studies demonstrating the mechanism of sensorimotor simulation in different cognitive domains. Empirical studies that specify conditions under which embodiment occurs in different domains will be discussed and evaluated. Examples of relevant domains are language comprehension (Tucker & Ellis, 2004, autobiographical memory (Dijkstra, Kaschak, & Zwaan, 2007, gestures (Alibali, Boncoddo, & Hostetter, 2014, facial mimicry (Stel & Vonk, 2010, and problem solving (Wiemers, Bekkering, & Lindemann, 2014. The focus of the review is on supporting claims regarding sensorimotor simulation as well as on factors that modulate dynamic relationships between sensorimotor components in action and cognitive domains, such as expertise (Boschker, Bakker, & Michaels, 2002. This discussion takes place within the context of currently debated issues, specifically the need to specify the underlying mechanisms of embodied representations (Zwaan, 2014; Körner, Topolinski, & Strack, 2015.

  14. An FMM-FFT Accelerated SIE Simulator for Analyzing EM Wave Propagation in Mine Environments Loaded with Conductors

    KAUST Repository

    Yucel, Abdulkadir C.

    2018-02-05

    A fast and memory efficient 3D full wave simulator for analyzing electromagnetic (EM) wave propagation in electrically large and realistic mine tunnels/galleries loaded with conductors is proposed. The simulator relies on Muller and combined field surface integral equations (SIEs) to account for scattering from mine walls and conductors, respectively. During the iterative solution of the system of SIEs, the simulator uses a fast multipole method - fast Fourier transform (FMM-FFT) scheme to reduce CPU and memory requirements. The memory requirement is further reduced by compressing large data structures via singular value and Tucker decompositions. The efficiency, accuracy, and real-world applicability of the simulator are demonstrated through characterization of EM wave propagation in electrically large mine tunnels/galleries loaded with conducting cables and mine carts.

  15. Morphology and distribution of a deep-water Narcomedusa (Solmarisidae from the northeast Pacific

    Directory of Open Access Journals (Sweden)

    Mary Needler Arai

    2000-12-01

    Full Text Available Specimens of Solmaris sp. (Solmarisidae, Narcomedusae with only four tentacles were collected in the northeast Pacific. The majority were collected in Canadian Pacific waters by Tucker trawl from stations outside the 500-m contour off the west coast of Vancouver Island, British Columbia, at depths of 300-700 m. Six were collected in vertical hauls at Station P (50oN, 145oW. The oral stomach wall contains three prominent rings of tissue. There is a peripheral ring of aggregates of gonadal tissue. Nematogenic areas with three types of nematocysts form an intermediate ring closer to the mouth than the gonads, and they also overlie the gonadal position where nematogenic tissue extends out to the base of each tentacle. Immediately surrounding the mouth, the epithelium of the oral stomach wall is greatly thickened, and this central ring contains large numbers of secretory cells.

  16. Los norteamericanos que re-inventaron a los pueblos de México. Los emprendedores extranjeros en la redefinición de la cultura y el turismo

    DEFF Research Database (Denmark)

    Balslev, Helene; Velázquez, Mario

    2020-01-01

    emprendedores que analizaremos son individuos, -en este caso turistas a mediados del siglo XX,- los cuales decidieron iniciar un negocio en lugares de México que, hasta antes de su presencia, no eran considerados destinos turísticos y pasaban por una crisis económica por lo que sus proyectos parecían una...... aventura destinada al fracaso. Estos emprendedores aprovecharon una oportunidad no explotada que tenían viajeros norteamericanos por consumir y conocer lugares mexicanos (Austin, Stevenson y Wei-Skillem, 2006).......En este artículo buscamos analizar cuál es el papel que tuvo el emprendimiento que desempeñaron turistas en la reconstrucción de la cultura, la identidad y la economía de aquellas poblaciones que habitaron de manera temporal o permanente (Hall & Tucker, 2004; Johannison, 2011). El tipo de...

  17. Using discrete-time mathematical programming to optimise the extraction rate of a durable non-renewable resource with a single primary supplier

    Directory of Open Access Journals (Sweden)

    Albert Corominas

    Full Text Available A non-linear discrete-time mathematical program model is proposed to determining the optimal extraction policy for a single primary supplier of a durable non-renewable resource, such as gemstones or some metals. Karush, Kuhn and Tucker conditions allow obtaining analytic solutions and general properties of them in some specific settings. Moreover, provided that the objective function (i.e., the discounted value of the incomes throughout the planning horizon is concave, the model can be easily solved, even using standard commercial solver. However, the analysis of the solutions obtained for different assumptions of the values of the parameters show that the optimal extraction policies and the corresponding prices do not exhibit a general shape. Keywords: Durable non-renewable resources, Single primary supplier, Non-linear programming

  18. Modeling and Simulation of Fiber Orientation in Injection Molding of Polymer Composites

    Directory of Open Access Journals (Sweden)

    Jang Min Park

    2011-01-01

    Full Text Available We review the fundamental modeling and numerical simulation for a prediction of fiber orientation during injection molding process of polymer composite. In general, the simulation of fiber orientation involves coupled analysis of flow, temperature, moving free surface, and fiber kinematics. For the governing equation of the flow, Hele-Shaw flow model along with the generalized Newtonian constitutive model has been widely used. The kinematics of a group of fibers is described in terms of the second-order fiber orientation tensor. Folgar-Tucker model and recent fiber kinematics models such as a slow orientation model are discussed. Also various closure approximations are reviewed. Therefore, the coupled numerical methods are needed due to the above complex problems. We review several well-established methods such as a finite-element/finite-different hybrid scheme for Hele-Shaw flow model and a finite element method for a general three-dimensional flow model.

  19. Cross-Cultural and Gender Differences in ADHD Among Young Adults.

    Science.gov (United States)

    Gómez-Benito, Juana; Van de Vijver, Fons J R; Balluerka, Nekane; Caterino, Linda

    2015-10-29

    This study explored the effect of cultural and gender differences in ADHD among Spanish, African American, Hispanic American, and European American young adults. Structural equivalence between the four groups was examined by Tucker's phi coefficient. A MANCOVA was carried out with cultural groups and gender as factors and age as covariate. Structural equivalence was observed across all groups, and no differential item functioning was found. No significant effect was found for gender, although, with the exception of the Hispanic group, males scored higher than females. Furthermore, small, though significant, cultural differences were found. The lowest levels of ADHD were observed in the European American group and the highest in the Hispanic American group. ADHD symptoms, notably inattention, showed some decline with age. Findings extend existing data and suggest a relationship between culture and the development of ADHD, which might be mediated by parenting style. © The Author(s) 2015.

  20. MATLAB tensor classes for fast algorithm prototyping.

    Energy Technology Data Exchange (ETDEWEB)

    Bader, Brett William; Kolda, Tamara Gibson (Sandia National Laboratories, Livermore, CA)

    2004-10-01

    Tensors (also known as mutidimensional arrays or N-way arrays) are used in a variety of applications ranging from chemometrics to psychometrics. We describe four MATLAB classes for tensor manipulations that can be used for fast algorithm prototyping. The tensor class extends the functionality of MATLAB's multidimensional arrays by supporting additional operations such as tensor multiplication. The tensor as matrix class supports the 'matricization' of a tensor, i.e., the conversion of a tensor to a matrix (and vice versa), a commonly used operation in many algorithms. Two additional classes represent tensors stored in decomposed formats: cp tensor and tucker tensor. We descibe all of these classes and then demonstrate their use by showing how to implement several tensor algorithms that have appeared in the literature.

  1. A Regularization SAA Scheme for a Stochastic Mathematical Program with Complementarity Constraints

    Directory of Open Access Journals (Sweden)

    Yu-xin Li

    2014-01-01

    Full Text Available To reflect uncertain data in practical problems, stochastic versions of the mathematical program with complementarity constraints (MPCC have drawn much attention in the recent literature. Our concern is the detailed analysis of convergence properties of a regularization sample average approximation (SAA method for solving a stochastic mathematical program with complementarity constraints (SMPCC. The analysis of this regularization method is carried out in three steps: First, the almost sure convergence of optimal solutions of the regularized SAA problem to that of the true problem is established by the notion of epiconvergence in variational analysis. Second, under MPCC-MFCQ, which is weaker than MPCC-LICQ, we show that any accumulation point of Karash-Kuhn-Tucker points of the regularized SAA problem is almost surely a kind of stationary point of SMPCC as the sample size tends to infinity. Finally, some numerical results are reported to show the efficiency of the method proposed.

  2. A locational gaming model with CO2 emission tax and limits

    International Nuclear Information System (INIS)

    Yu, Z.; Preckel, P.V.; Nderitu, G.; Sparrow, F.T.

    2001-01-01

    This paper presents a locational (spatial) gaming model with CO 2 emission and transmission capacity limits. It is developed for simulating strategic behavior of electricity producers in deregulated electricity markets. The model has multiple players, each maximizing their individual profit with a CO 2 emission tax included to reflect the societal cost of environment damages caused by CO 2 emission from different locations. In the paper, the multiple-producer profits are converted into a set of Lagrangian functions with power production and supply as the primary control variables, resulting in a set of unconstrained, individual profit maximization equations. The Karush-Kuhn-Tucker necessary conditions are then derived and solved simultaneously incorporating Cournot gaming strategy. Case studies show the successful application of the model. (author)

  3. Juvenile Delinquency in Romania: The Indirect Result of the Transition Process

    Directory of Open Access Journals (Sweden)

    Andrea Fabian

    2010-11-01

    Full Text Available The general purpose of the research is to present the evolution of juvenile delinquency in Romania after 1989, with some of its social and psychological aspects. We use a comparative perspective: the general, Romanian framework will be compared with local situation occurred in Cluj county.The presentation is based on an extensive study of 420 delinquent juveniles, whose data on family situation, education, age, etc were analyzed and the youngsters were also tested with psychological tests. Looking at the data of the psychological tests (Nowicki & Strickland's Internal-External Control Scale for Children, McGuire & Priestley's Testing Your Reaction, Zuckerman-Kuhlman's Personality Questionnaire and Tucker's Inmate Dilemma Test and the descriptors of the social situation of juvenile delinquents, it looks like personality factors are associated with low school performance and school drop-out, as important determinants of delinquency. An integrative model was tested, to analyze the social and cognitive determinants of delinquency.

  4. Capacity bounds for parallel IM-DD optical wireless channels

    KAUST Repository

    Chaaban, Anas

    2016-07-26

    A system consisting of parallel intensity-modulation direct-detection optical wireless channels with a total average intensity constraint is studied. Capacity upper and lower bounds for this system are derived. If channel-state information is available at the transmitter, the bounds have to be optimized with respect to intensity allocation over the parallel channels. The optimization of the lower bound is non-convex, however, the Karush-Kuhn-Tucker conditions can be used to find a list of possible solutions one of which is optimal. The optimal solution can then be found by an exhaustive search algorithm, which is computationally expensive. To overcome this, we propose a low-complexity intensity allocation algorithm which is nearly optimal. The optimized capacity lower bound coincides with the capacity at high signal-to-noise ratio. © 2016 IEEE.

  5. Descriptive and predictive assessment of enzyme activity and enzyme related processes in biorefinery using IR spectroscopy and chemometrics

    DEFF Research Database (Denmark)

    Baum, Andreas

    the understanding of the structural properties of the extracted pectin. Secondly, enzyme kinetics of biomass converting enzymes was examined in terms of measuring enzyme activity by spectral evolution profiling utilizing FTIR. Chemometric multiway methods were used to analyze the tensor datasets enabling the second......-order calibration advantage (reference Theory of Analytical chemistry). As PAPER 3 illustrates the method is universally applicable without the need of any external standards and was exemplified by performing quantitative enzyme activity determinations for glucose oxidase, pectin lyase and a cellolytic enzyme blend...... (Celluclast 1.5L). In PAPER 4, the concept is extended to quantify enzyme activity of two simultaneously acting enzymes, namely pectin lyase and pectin methyl esterase. By doing so the multiway methods PARAFAC, TUCKER3 and NPLS were compared and evaluated towards accuracy and precision....

  6. A complementarity model for the European natural gas market

    International Nuclear Information System (INIS)

    Egging, Ruud; Gabriel, Steven A.; Holz, Franziska; Zhuang, Jifang

    2008-01-01

    In this paper, we present a detailed and comprehensive complementarity model for computing market equilibrium values in the European natural gas system. Market players include producers and their marketing arms which we call 'traders', pipeline and storage operators, marketers, LNG liquefiers, regasifiers, tankers, and three end-use consumption sectors. The economic behavior of producers, traders, pipeline and storage operators, liquefiers and regasifiers is modeled via optimization problems whose Karush-Kuhn-Tucker (KKT) optimality conditions in combination with market-clearing conditions form the complementarity system. The LNG tankers, marketers and consumption sectors are modeled implicitly via appropriate cost functions, aggregate demand curves, and ex post calculations, respectively. The model is run on several case studies that highlight its capabilities, including a simulation of a disruption of Russian supplies via Ukraine

  7. A "feasible direction" search for Lineal Programming problem solving

    Directory of Open Access Journals (Sweden)

    Jaime U Malpica Angarita

    2003-07-01

    Full Text Available The study presents an approach to solve linear programming problems with no artificial variables. A primal linear minimization problem is standard form and its associated dual linear maximization problem are used. Initially, the dual (or a partial dual program is solved by a "feasible direction" search, where the Karush-Kuhn-Tucker conditions help to verify its optimality and then its feasibility. The "feasible direction" search exploits the characteristics of the convex polyhedron (or prototype formed by the dual program constraints to find a starting point and then follows line segments, whose directions are found in afine subspaces defined by boundary hyperplanes of polyhedral faces, to find next points up to the (an optimal one. Them, the remaining dual constraints not satisfaced at that optimal dual point, if there are any, are handled as nonbasic variables of the primal program, which is to be solved by such "feasible direction" search.

  8. Classical and modern optimization methods in minimum weight design of elastic rotating disk with variable thickness and density

    International Nuclear Information System (INIS)

    Jafari, S.; Hojjati, M.H.; Fathi, A.

    2012-01-01

    Rotating disks work mostly at high angular velocity and this results a large centrifugal force and consequently induce large stresses and deformations. Minimizing weight of such disks yields to benefits such as low dead weights and lower costs. This paper aims at finding an optimal disk profiles for minimum weight design using the Karush-Kuhn-Tucker method (KKT) as a classical optimization method, simulated annealing (SA) and particle swarm optimization (PSO) as two modern optimization techniques. Some semi-analytical solutions for the elastic stress distribution in a rotating annular disk with uniform and variable thickness and density proposed by the authors in the previous works have been used. The von Mises failure criterion of optimum disk is used as an inequality constraint to make sure that the rotating disk does not fail. The results show that the minimum weight obtained for all three methods is almost identical. The KKT method gives a profile with slightly less weight (6% less than SA and 1% less than PSO) while the implementation of PSO and SA methods are easier and provide more flexibility compared with those of the KKT method. The effectiveness of the proposed optimization methods is shown. - Highlights: ► Karush-Kuhn-Tucker, simulated annealing and particle swarm methods are used. ► The KKT gives slightly less weight (6% less than SA and 1% less than PSO). ► Implementation of PSO and SA methods are easier and provide more flexibility. ► The effectiveness of the proposed optimization methods is shown.

  9. Incorporating price-responsive customers in day-ahead scheduling of smart distribution networks

    International Nuclear Information System (INIS)

    Mazidi, Mohammadreza; Monsef, Hassan; Siano, Pierluigi

    2016-01-01

    Highlights: • Proposing a model for incorporating price-responsive customers in day-ahead scheduling of smart distribution networks; this model provides a win–win situation. • Introducing a risk management model based on a bi-level information-gap decision theory and recasting it into its equivalent single-level robust optimization problem using Karush–Kuhn–Tucker optimality conditions. • Utilizing mixed-integer linear programing formulation that is efficiently solved by commercial optimization software. - Abstract: Demand response and real-time pricing of electricity are key factors in a smart grid as they can increase economic efficiency and technical performances of power grids. This paper focuses on incorporating price-responsive customers in day-ahead scheduling of smart distribution networks under a dynamic pricing environment. A novel method is proposed and formulated as a tractable mixed integer linear programming optimization problem whose objective is to find hourly sale prices offered to customers, transactions (purchase/sale) with the wholesale market, commitment of distribution generation units, dispatch of battery energy storage systems and planning of interruptible loads in a way that the profit of the distribution network operator is maximized while customers’ benefit is guaranteed. To hedge distribution network operator against financial risk arising from uncertainty of wholesale market prices, a risk management model based on a bi-level information-gap decision theory is proposed. The proposed bi-level problem is solved by recasting it into its equivalent single-level robust optimization problem using Karush–Kuhn–Tucker optimality conditions. Performance of the proposed model is verified by applying it to a modified version of the IEEE 33-bus distribution test network. Numerical results demonstrate the effectiveness and efficiency of the proposed method.

  10. Classical and modern optimization methods in minimum weight design of elastic rotating disk with variable thickness and density

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, S. [Faculty of Mechanical Engineering, Babol University of Technology, P.O. Box 484, Babol (Iran, Islamic Republic of); Hojjati, M.H., E-mail: Hojjati@nit.ac.ir [Faculty of Mechanical Engineering, Babol University of Technology, P.O. Box 484, Babol (Iran, Islamic Republic of); Fathi, A. [Faculty of Mechanical Engineering, Babol University of Technology, P.O. Box 484, Babol (Iran, Islamic Republic of)

    2012-04-15

    Rotating disks work mostly at high angular velocity and this results a large centrifugal force and consequently induce large stresses and deformations. Minimizing weight of such disks yields to benefits such as low dead weights and lower costs. This paper aims at finding an optimal disk profiles for minimum weight design using the Karush-Kuhn-Tucker method (KKT) as a classical optimization method, simulated annealing (SA) and particle swarm optimization (PSO) as two modern optimization techniques. Some semi-analytical solutions for the elastic stress distribution in a rotating annular disk with uniform and variable thickness and density proposed by the authors in the previous works have been used. The von Mises failure criterion of optimum disk is used as an inequality constraint to make sure that the rotating disk does not fail. The results show that the minimum weight obtained for all three methods is almost identical. The KKT method gives a profile with slightly less weight (6% less than SA and 1% less than PSO) while the implementation of PSO and SA methods are easier and provide more flexibility compared with those of the KKT method. The effectiveness of the proposed optimization methods is shown. - Highlights: Black-Right-Pointing-Pointer Karush-Kuhn-Tucker, simulated annealing and particle swarm methods are used. Black-Right-Pointing-Pointer The KKT gives slightly less weight (6% less than SA and 1% less than PSO). Black-Right-Pointing-Pointer Implementation of PSO and SA methods are easier and provide more flexibility. Black-Right-Pointing-Pointer The effectiveness of the proposed optimization methods is shown.

  11. Aplicação foliar de tratamentos para o controle do míldio e da podridão-de-escamas de bulbos de cebola Foliar spray of treatments in the control of downy mildew and bulb rot in onion

    Directory of Open Access Journals (Sweden)

    João Américo Wordell Filho

    2007-12-01

    Full Text Available Em experimento de campo, avaliou-se o efeito da aplicação foliar de tratamentos para o controle do míldio (Peronospora destructor e da podridão de bulbos (Burkholderia cepacia de cebola: testemunha, clorotalonil/metalaxyl + clorotalonil, fosfito de potássio, fertilizante foliar (03-00-16, N-P-K, calda bordalesa, calda bordalesa/fosfito de potássio, acibenzolar-S-methyl, pulverizados semanalmente; extrato de alga (Ulva fasciata e ulvana, aplicados a cada 7, 14 e 21 dias. Somente a pulverização semanal com fungicidas sintéticos ou com o fertilizante (03-00-16; 400 mL de p.c./100 L foi capaz de reduzir significativamente a severidade do míldio, em 60 ou 23%, respectivamente, em relação à testemunha não pulverizada, sem aumentar o rendimento de bulbos. O tratamento com fertilizantes ricos em potássio resultou em maior incidência da podridão de bulbos armazenados por cinco meses. O conteúdo de açúcares solúveis e incidência da podridão de bulbos de cebola foram correlacionados significativamente (-0,629, p A field experiment was carried out to evaluate the effect of foliar sprays with the following treatments on the downy mildew (Peronospora destructor and bulb rot (Burkholderia cepacia in onions: non-treated control, fungicide chlorotalonil/metalaxyl + chlorotalonil, potassium phosphite, foliar fertilizer (03-00-16, N-P-K, bordeaux mixture, bordeaux mixture/potassium phosphite, acibenzolar-S-methyl weekly applied; extract of alga Ulva fasciata and ulvan sprayed every 7, 14 and 21 days. Only the weekly spraying of fungicides and fertilizer (03-00-16, 400 mL/100 L significantly reduced the mildew severity by 60 and 23%, respectively, but did not increase the bulb yield. The foliar application of potassium rich fertilizers resulted in a higher incidence of rotten bulbs after 5 months in storage. Soluble sugar content and rot incidence of onion bulbs were significantly correlated (-0,629, p < 0,05.

  12. Multiway modeling and analysis in stem cell systems biology

    Directory of Open Access Journals (Sweden)

    Vandenberg Scott L

    2008-07-01

    Full Text Available Abstract Background Systems biology refers to multidisciplinary approaches designed to uncover emergent properties of biological systems. Stem cells are an attractive target for this analysis, due to their broad therapeutic potential. A central theme of systems biology is the use of computational modeling to reconstruct complex systems from a wealth of reductionist, molecular data (e.g., gene/protein expression, signal transduction activity, metabolic activity, etc.. A number of deterministic, probabilistic, and statistical learning models are used to understand sophisticated cellular behaviors such as protein expression during cellular differentiation and the activity of signaling networks. However, many of these models are bimodal i.e., they only consider row-column relationships. In contrast, multiway modeling techniques (also known as tensor models can analyze multimodal data, which capture much more information about complex behaviors such as cell differentiation. In particular, tensors can be very powerful tools for modeling the dynamic activity of biological networks over time. Here, we review the application of systems biology to stem cells and illustrate application of tensor analysis to model collagen-induced osteogenic differentiation of human mesenchymal stem cells. Results We applied Tucker1, Tucker3, and Parallel Factor Analysis (PARAFAC models to identify protein/gene expression patterns during extracellular matrix-induced osteogenic differentiation of human mesenchymal stem cells. In one case, we organized our data into a tensor of type protein/gene locus link × gene ontology category × osteogenic stimulant, and found that our cells expressed two distinct, stimulus-dependent sets of functionally related genes as they underwent osteogenic differentiation. In a second case, we organized DNA microarray data in a three-way tensor of gene IDs × osteogenic stimulus × replicates, and found that application of tensile strain to a

  13. Syndemic Factors Mediate the Relationship between Sexual Stigma and Depression among Sexual Minority Women and Gender Minorities.

    Science.gov (United States)

    Logie, Carmen H; Lacombe-Duncan, Ashley; Poteat, Tonia; Wagner, Anne C

    Stigma and discrimination contribute to elevated depression risks among sexual minority women (SMW) and gender minority (GM) people who identify as lesbian, bisexual, or queer. Syndemics theory posits that adverse psychosocial outcomes cluster to negatively impact health and mental health outcomes among sexual minorities. We tested whether a syndemic condition composed of low social support, low self-rated health, low self-esteem, and economic insecurity mediated the relationship between sexual stigma and depressive symptoms among SMW/GM. We implemented a cross-sectional, Internet-based survey with SMW and GM in Toronto, Canada. We conducted structural equation modeling using maximum likelihood estimation to test a conceptual model of pathways between sexual stigma, syndemic factors, and depressive symptoms. A total of 391 SMW/GM with a mean age of 30.9 (SD = 7.62) were included in the analysis. The model fit for a latent syndemics construct consisting of psychosocial variables (low social support, low self-rated health, low self-esteem, economic insecurity) was very good (χ 2  = 6.022, df = 2, p = .049; comparative fit index = 0.973, Tucker-Lewis index = 0.918, root-mean square error of approximation = 0.072). In the simultaneous model, sexual stigma had a significant direct effect on depression. When the syndemic variable was added as a mediator, the direct path from sexual stigma to depression was no longer significant, suggesting mediation. The model fit the data well: χ2 = 33.50, df = 12, p = .001; comparative fit index = 0.951, Tucker-Lewis index = 0.915, root-mean square error of approximation = 0.068. Our results highlight the salience of considering both sexual stigma and syndemic factors to explain mental health disparities experienced by SMW and GM. Addressing sexual stigma in the context of co-occurring psychosocial factors and economic insecurity will be key to achieving optimal health for SMW and GM. Copyright © 2017 Jacobs

  14. Theoretical Aspects Regarding the Optimal Taxation of Effort With More Conditions

    Directory of Open Access Journals (Sweden)

    Prof. Dumitru MARIN PhD

    2017-09-01

    and demonstrate the implementation condition that is equivalent to the assertion that the plurality of admissible solutions is unclear gives a solution perspective applicable in most cases. The authors propose, by synthesizing, conditions (sentences that demonstrate that the model used is one that must be considered and can be successfully used in optimal taxation of the multi-state effort. In the explanatory approach, it is also appreciated that the combination of the Kuhn-Tucker multipliers of the two constructions can determine the Lagrange function. This feature built by all Kuhn-Tucker multipliers is strictly positive and the level of effort is optimal given by a series of equalities that imply a final aspect of its use.

  15. Modelling spatial and temporal variations in the water quality of an artificial water reservoir in the semiarid Midwest of Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Cid, Fabricio D., E-mail: fabricio.cid@gmail.com [Laboratory of Biology ' Prof. E. Caviedes Codelia' , Facultad de Ciencias Humanas, Universidad Nacional de San Luis, San Luis (Argentina); Laboratory of Integrative Biology, Institute for Multidisciplinary Research in Biology (IMIBIO-SL), Consejo Nacional de Investigaciones Cientificas y Tecnicas, San Luis (Argentina); Department of Biochemistry and Biological Sciences, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Anton, Rosa I. [Department of Analytical Chemistry, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Pardo, Rafael; Vega, Marisol [Department of Analytical Chemistry, Facultad de Ciencias, Universidad de Valladolid, Valladolid (Spain); Caviedes-Vidal, Enrique [Laboratory of Biology ' Prof. E. Caviedes Codelia' , Facultad de Ciencias Humanas, Universidad Nacional de San Luis, San Luis (Argentina); Laboratory of Integrative Biology, Institute for Multidisciplinary Research in Biology (IMIBIO-SL), Consejo Nacional de Investigaciones Cientificas y Tecnicas, San Luis (Argentina); Department of Biochemistry and Biological Sciences, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina)

    2011-10-31

    Highlights: {yields} Water quality of an Argentinean reservoir has been investigated by N-way PCA. {yields} PARAFAC mode modelled spatial and seasonal variations of water composition. {yields} Two factors related with organic and lead pollution have been identified. {yields} The most polluted areas of the reservoir were located, and polluting sources identified. - Abstract: Temporal and spatial patterns of water quality of an important artificial water reservoir located in the semiarid Midwest of Argentina were investigated using chemometric techniques. Surface water samples were collected at 38 points of the water reservoir during eleven sampling campaigns between October 1998 and June 2000, covering the warm wet season and the cold dry season, and analyzed for dissolved oxygen (DO), conductivity, pH, ammonium, nitrate, nitrite, total dissolved solids (TDS), alkalinity, hardness, bicarbonate, chloride, sulfate, calcium, magnesium, fluoride, sodium, potassium, iron, aluminum, silica, phosphate, sulfide, arsenic, chromium, lead, cadmium, chemical oxygen demand (COD), biochemical oxygen demand (BOD), viable aerobic bacteria (VAB) and total coliform bacteria (TC). Concentrations of lead, ammonium, nitrite and coliforms were higher than the maximum allowable limits for drinking water in a large proportion of the water samples. To obtain a general representation of the spatial and temporal trends of the water quality parameters at the reservoir, the three-dimensional dataset (sampling sites x parameters x sampling campaigns) has been analyzed by matrix augmentation principal component analysis (MA-PCA) and N-way principal component analysis (N-PCA) using Tucker3 and PARAFAC (Parallel Factor Analysis) models. MA-PCA produced a component accounting for the general behavior of parameters associated with organic pollution. The Tucker3 models were not appropriate for modelling the water quality dataset. The two-factor PARAFAC model provided the best picture to understand the

  16. Modelling spatial and temporal variations in the water quality of an artificial water reservoir in the semiarid Midwest of Argentina

    International Nuclear Information System (INIS)

    Cid, Fabricio D.; Anton, Rosa I.; Pardo, Rafael; Vega, Marisol; Caviedes-Vidal, Enrique

    2011-01-01

    Highlights: → Water quality of an Argentinean reservoir has been investigated by N-way PCA. → PARAFAC mode modelled spatial and seasonal variations of water composition. → Two factors related with organic and lead pollution have been identified. → The most polluted areas of the reservoir were located, and polluting sources identified. - Abstract: Temporal and spatial patterns of water quality of an important artificial water reservoir located in the semiarid Midwest of Argentina were investigated using chemometric techniques. Surface water samples were collected at 38 points of the water reservoir during eleven sampling campaigns between October 1998 and June 2000, covering the warm wet season and the cold dry season, and analyzed for dissolved oxygen (DO), conductivity, pH, ammonium, nitrate, nitrite, total dissolved solids (TDS), alkalinity, hardness, bicarbonate, chloride, sulfate, calcium, magnesium, fluoride, sodium, potassium, iron, aluminum, silica, phosphate, sulfide, arsenic, chromium, lead, cadmium, chemical oxygen demand (COD), biochemical oxygen demand (BOD), viable aerobic bacteria (VAB) and total coliform bacteria (TC). Concentrations of lead, ammonium, nitrite and coliforms were higher than the maximum allowable limits for drinking water in a large proportion of the water samples. To obtain a general representation of the spatial and temporal trends of the water quality parameters at the reservoir, the three-dimensional dataset (sampling sites x parameters x sampling campaigns) has been analyzed by matrix augmentation principal component analysis (MA-PCA) and N-way principal component analysis (N-PCA) using Tucker3 and PARAFAC (Parallel Factor Analysis) models. MA-PCA produced a component accounting for the general behavior of parameters associated with organic pollution. The Tucker3 models were not appropriate for modelling the water quality dataset. The two-factor PARAFAC model provided the best picture to understand the spatial and

  17. Inter-professional relationships issues among iranian nurses and physicians: A qualitative study

    Directory of Open Access Journals (Sweden)

    Samaneh Nakhaee

    2017-01-01

    Full Text Available Introduction: Nurse–physician inter-professional relationship is an important issue in health care system that can affect job satisfaction and patient care quality. The present study explores the major issues of nurse–physician inter-professional relationships in Iran. Materials and Methods: In this in-depth qualitative content analysis study conducted in 2014, 12 participants (5 physicians and 7 nurses were recruited from two educational hospitals. The data were collected from deep, open, and unstructured interviews, and analyzed based on content analysis. Results: The participants in this study included 12 individuals, 6 females and 6 males, with the age ranging 27–48 years and tenure ranging 4–17 years. Four themes were identified, namely, divergent attitudes, uneven distribution of power, mutual trust destructors, and prudence imposed on nurses. Conclusions: The results revealed some major inter-professional issues and challenges in nurse–physician relationships, some of which are context-specific whereas others should be regarded as universal. It is through a deep knowledge of these issues that nurses and physicians can establish better collaborative inter-professional relationships.

  18. Ozone decay in chemical reactor for ozone-dynamical disintegration of used tyres

    International Nuclear Information System (INIS)

    Golota, V.I.; Manuilenko, O.V.; Taran, G.V.; Dotsenko, Yu.V.; Pismenetskii, A.S.; Zamuriev, A.A.; Benitskaja, V.A.

    2011-01-01

    The ozone decay kinetics in the chemical reactor intended for used tyres disintegration is investigated experimentally and theoretically. Ozone was synthesized in barrierless ozonizers based on the streamer discharge. The chemical reactor for tyres disintegration in the ozone-air environment represents the cylindrical chamber, which feeds from the ozonizer by ozone-air mixture with the specified rate of volume flow, and with known ozone concentration. The output of the used mixture, which rate of volume flow is also known, is carried out through the ozone destructor. As a result of ozone decay in the volume and on the reactor walls, and output of the used mixture from the reactor, the ozone concentration in the reactor depends from time. In the paper, the analytical expression for dependence of ozone concentration in the reactor from time and from the parameters of a problem such as the volumetric feed rate, ozone concentration on the input in the reactor, volume flow rate of the used mixture, the volume of the reactor and the area of its internal surface is obtained. It is shown that experimental results coincide with good accuracy with analytical ones.

  19. Uso de enxofre na cultura da cebola em sistemas orgânico e convencional para o manejo de tripes e míldio e análise de rendimento

    Directory of Open Access Journals (Sweden)

    Paulo Antonio de Souza Gonçalves

    2017-08-01

    Full Text Available O objetivo deste estudo foi avaliar o efeito de doses de enxofre aplicado em cobertura no solo no manejo de tripes, Thrips tabaci (Thysanopetra: Thripidae, e de míldio, Peronospora destructor, produtividade e rendimento pós-colheita de cebola, em sistemas orgânico e convencional. Os tratamentos foram doses de enxofre: 25 kg ha-1, 50 kg ha-1, e 75 kg ha-1 e testemunha sem aplicação. Os experimentos foram conduzidos separadamente em sistemas orgânico e convencional. As doses de enxofre foram aplicadas conjuntamente à adubação de cobertura aos 33 e 36 dias após o transplantio para sistema orgânico e convencional, respectivamente. A fonte de enxofre foi o fertilizante Sulfacal® (Ca= 16%, S=13%. O manejo fitossanitário, a produtividade e rendimento pós-colheita não foram influenciados pelos tratamentos. A adição de enxofre não alterou os demais atributos físico-químicos do solo. O nível foliar de enxofre foi incrementado de acordo com uma relação linear positiva em sistema orgânico y= 4,2 + 0,02.x (R2= 0,41%, p= 0,0023 e foi incrementado na dose de 75 kg ha-1 no convencional.

  20. Modelo climático para previsão do míldio da cebola

    Directory of Open Access Journals (Sweden)

    Leandro Luiz Marcuzzo

    2016-03-01

    Full Text Available RESUMO A partir de dados publicados na literatura, elaborou-se um modelo de previsão do míldio da cebola, causado por Peronospora destructor. O modelo desenvolvido baseia-se nas condições climáticas favoráveis para o processo infeccioso, baseado na temperatura e na duração do molhamento foliar. Obteve-se a interação que representa os dois fatores sobre a probabilidade de infecção. Com auxílio da planilha eletrônica Excell, calculou-se a duração do período de molhamento foliar para obter diferentes probabilidades de infecção do patógenos em diferentes temperaturas. Com os dados foi elaborada uma tabela que poderá ser usada na programação computacional que registra a duração do período de molhamento foliar e a temperatura média e automaticamente o valor diário de probabilidade de ocorrência de infecção. O modelo será validado em experimentos conduzidos no campo e com infecção natural, em Rio do Sul, SC.