735 research outputs found
A negative effect of a pathogen on its vector? A plant pathogen increases the vulnerability of its vector to attack by natural enemies
Plant pathogens that are dependent on arthropod vectors for transmission from host to host may enhance their own success by promoting vector survival and/or performance. The effect of pathogens on vectors may be direct or indirect, with indirect effects mediated by increases in host quality or reductions in the vulnerability of vectors to natural enemies. We investigated whether the bird cherry-oat aphid Rhopalosiphum padi, a vector of cereal yellow dwarf virus (CYDV) in wheat, experiences a reduction in rates of attack by the parasitoid wasp Aphidius colemani when actively harboring the plant pathogen. We manipulated the vector status of aphids (virus carrying or virus free) and evaluated the impact on the rate of attack by wasps. We found that vector status did not influence the survival or fecundity of aphids in the absence of parasitoids. However, virus-carrying aphids experienced higher rates of parasitism and greater overall population suppression by parasitoid wasps than virus-free aphids. Moreover, virus-carrying aphids were accepted as hosts by wasps more often than virus-free aphids, with a greater number of wasps stinging virus-carrying aphids following assessment by antennal palpations than virus-free aphids. Therefore, counter to the prevailing idea that persistent vector-borne pathogens enhance the performance of their vectors, we found that infectious aphids actively carrying a plant pathogen experience greater vulnerability to natural enemies. Our results suggest that parasitoids may contribute to the successful biological control of CYDV by disproportionately impacting virus-carrying vectors, and thus reducing the proportion of vectors in the population that are infectious
A negative effect of a pathogen on its vector? A plant pathogen increases the vulnerability of its vector to attack by natural enemies
Plant pathogens that are dependent on arthropod vectors for transmission from host to host may enhance their own success by promoting vector survival and/or performance. The effect of pathogens on vectors may be direct or indirect, with indirect effects mediated by increases in host quality or reductions in the vulnerability of vectors to natural enemies. We investigated whether the bird cherry-oat aphid Rhopalosiphum padi, a vector of cereal yellow dwarf virus (CYDV) in wheat, experiences a reduction in rates of attack by the parasitoid wasp Aphidius colemani when actively harboring the plant pathogen. We manipulated the vector status of aphids (virus carrying or virus free) and evaluated the impact on the rate of attack by wasps. We found that vector status did not influence the survival or fecundity of aphids in the absence of parasitoids. However, virus-carrying aphids experienced higher rates of parasitism and greater overall population suppression by parasitoid wasps than virus-free aphids. Moreover, virus-carrying aphids were accepted as hosts by wasps more often than virus-free aphids, with a greater number of wasps stinging virus-carrying aphids following assessment by antennal palpations than virus-free aphids. Therefore, counter to the prevailing idea that persistent vector-borne pathogens enhance the performance of their vectors, we found that infectious aphids actively carrying a plant pathogen experience greater vulnerability to natural enemies. Our results suggest that parasitoids may contribute to the successful biological control of CYDV by disproportionately impacting virus-carrying vectors, and thus reducing the proportion of vectors in the population that are infectious
Transcriptional regulatory networks controlling woolliness in peach in response to preharvest gibberellin application and cold storage
BACKGROUND: Postharvest fruit conservation relies on low temperatures and manipulations of hormone metabolism to maintain sensory properties. Peaches are susceptible to chilling injuries, such as âwoollinessâ that is caused by juice loss leading to a âwoolyâ fruit texture. Application of gibberellic acid at the initial stages of pit hardening impairs woolliness incidence, however the mechanisms controlling the response remain unknown. We have employed genome wide transcriptional profiling to investigate the effects of gibberellic acid application and cold storage on harvested peaches. RESULTS: Approximately half of the investigated genes exhibited significant differential expression in response to the treatments. Cellular and developmental process gene ontologies were overrepresented among the differentially regulated genes, whereas sequences in cell death and immune response categories were underrepresented. Gene set enrichment demonstrated a predominant role of cold storage in repressing the transcription of genes associated to cell wall metabolism. In contrast, genes involved in hormone responses exhibited a more complex transcriptional response, indicating an extensive network of crosstalk between hormone signaling and low temperatures. Time course transcriptional analyses demonstrate the large contribution of gene expression regulation on the biochemical changes leading to woolliness in peach. CONCLUSION: Overall, our results provide insights on the mechanisms controlling the complex phenotypes associated to postharvest textural changes in peach and suggest that hormone mediated reprogramming previous to pit hardening affects the onset of chilling injuries. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12870-015-0659-2) contains supplementary material, which is available to authorized users
Virtual Broking Coding for Reliable In-Network Storage on WSANs
International audienceThe emerging Internet of Things (IoT) paradigmmakes Wireless Sensor and Actuator Networks (WSANs) seemas a central element for data production and consumption. Inthis realm, where data are produced and consumed within thenetwork, WSANs have as a challenge to perform in-network datastorage considering their resource shortage. In this paper, wepropose the Virtual Broking Coding (VBC) as a data storagescheme compliant with WSANs constraints. As such, VBCensures a reliable data storage and an efficient mechanism fordata retrievability. To evaluate our proposed solution, we presenta theoretical analysis as well as a simulation study. Using both,we show that VBC reduces the cost incurred by the codingtechniques; and increases the delivery ratio of the requesteddata. The results presented by VBC suggest this solution as anew direction on how to use network coding based schemes toaddress the WSAN in-network storage problem
Application of remote sensing to the study of the pelagic spiny lobster larval transport in the Tropical Atlantic
A conectividade de populaçÔes marinhas atravĂ©s da dispersĂŁo larval Ă© crucial para a manutenção da produção pesqueira e da biodiversidade. A dispersĂŁo de larvas ocorre em diferentes escalas espaciais e temporais, de forma que o recobrimento global e escala sinĂłptica fazem dos dados de satĂ©lite ferramentas importantes para esses estudos. O objetivo deste artigo Ă© apresentar os resultados do uso de dados de correntes geostrĂłficas derivadas de satĂ©lites altĂmetros para simular o transporte de larvas de lagosta espinhosa no oceano AtlĂąntico Tropical. As simulaçÔes foram realizadas ao longo do AtlĂąntico Tropical (20ÂșN - 15ÂșS), iniciando em quatro locais (Cabo Verde, Costa do Marfim, Ilha de AscensĂŁo e ArquipĂ©lago de Fernando de Noronha). Foi utilizado um modelo advectivo/difusivo forçado com o campo mĂ©dio de circulação geostrĂłfica calculado entre 2001 e 2005 e outro forçado com campo correspondente ao evento de El Niño 2002/2003. Os resultados obtidos sugerem que hĂĄ uma intensificação de processos oceĂąnicos de meso-escala durante o ano de El Niño, que promove a conectividade entre diferentes estoques e aumenta as chances de ocorrer um fluxo genĂ©tico. Os dados de correntes geostrĂłficas gerados a partir de satĂ©lites altĂmetros incorporados a um modelo advectivo/difusivo simples podem prover informaçÔes importantes acerca da dinĂąmica fĂsica necessĂĄrias para conduzir estudos sobre dispersĂŁo larval.The connectivity of marine populations via larval dispersal is crucial for the maintenance of fisheries production and biodiversity. Because larval dispersion takes place on different spatial scales, global operational satellite data can be successfully used to investigate the connectivity of marine populations on different spatial and temporal scales. In fact, satellite data have long been used for the study of the large and mesoscale biological processes associated with ocean dynamics. This paper presents simulations of spiny lobster larvae transport in the Tropical Atlantic using the geostrophic currents, generated by altimetry that feeds an advection/diffusion model. Simulations were conducted over the Tropical Atlantic (20ÂșN to 15ÂșS), considering four larvae release areas: the Cape Verde Archipelago, the Ivory Coast, Ascension Island and Fernando de Noronha Archipelago. We used mean geostrophic current (MGC) calculated from 2001 to 2005 to represent the mean circulation of the Tropical Atlantic. We also ran the model for the El Niño geostrophic current regime (ENGC) using part of the MGC data, representing the El Niño 2002/2003 event. Results suggest that the intensification of the mesoscale ocean processes associated with El Niño events promotes the connectivity between populations, increasing the chances of a genetic flux among different stocks. We concluded that the altimetry geostrophic current data together with a relatively simple advection/diffusion model can provide useful information about the physical dynamics necessary to conduct studies on larval dispersion
Improving the learning experience and learning environment of adults in Higher Education â Project LIHE: the Portuguese case
Project LIHE: the Portuguese Case. ESREA Fourth Access Network
Conference â âEquity, Access and Participation: Research, Policy and Practiceâ. Edinburgh (Scotland),
11 â 13 December, 2003.The promotion of a knowledge-based society needs, on one hand, technological
infrastructure and, on the other hand, a workforce with the necessary skills,
knowledge and competences, supported by a well-structured initial education and
by a continuous learning program. In the last years, Universities have opened
their doors to all citizens, regardless of their status or origin, if they have the
capacity to benefit from the educational services on offer. This strategy has
allowed mature students to enter (or re-enter) the formal higher education
system. Although these students may possess a richness of experience, they can
also have difficulty in adapting to the pedagogical approaches of learning and
teaching and their attitudes and problems are not necessarily the same as those
of traditional students. It is in this context that the project LIHE â Learning in
Higher Education emerges. In this paper, the background of the project and the
most relevant literature for the subject are briefly described. It is followed by a
presentation of the project aims, objectives and methodological approaches. The
Portuguese case is introduced, together with the results of questionnaires and
interviews. Some preliminary conclusions are outlined. Finally, avenues of future
research are discusse
Myogenic Potential of Murine Embryonic Stem Cells in the Dmdmdx Mouse Model for Duchenne Muscular Dystrophy
Skin picking treatment with the Rothbaum cognitive behavioral therapy protocol : a randomized clinical trial
Introduction: Although behavioral therapies can effectively treat skin picking disorder (SPD), there is no standardized treatment for improving SPD and its comorbidities and there is no group intervention option. This trial aimed to adapt the Rothbaum trichotillomania protocol to SPD (Study 1) and test its efficacy for treating SPD and comorbidities in individual and group formats (Study 2). Methods: The adapted protocol was applied to 16 SPD patients, who were allocated to group or individual treatment (Study 1). Afterwards, 54 patients were randomly allocated to treatment in an individual (n=27) or group format (n=27) (Study 2). In both studies, assessments of SPD severity, anxiety, depression, clinical status and skin lesion severity were performed at baseline and the endpoint. Results: The adapted protocol was feasible in both treatment modalities (Study 1) and led to high SPD remission rates (individual 63%; group 52%), with no significant difference between intervention types (p = 0.4) (Study 2). SPD, anxiety, and depression symptoms and objective patient lesion measures improved after treatment. There was large effect size for SPD symptom improvement in both treatment types (Cohenâs d: group = 0.88; individual = 1.15) (Study 2). Conclusion: The adapted Rothbaum protocol was effective for SPD remission, comorbidities, and skin lesions, both in individual and group formats
Coeval perpendicular shortenings in the Brasilia belt : collision of irregular plate margins leading to oroclinal bending in the Neoproterozoic of central Brazil
The three belts which form the Tocantins province (central Brazil) records
Neoproterozoic-EoPaleozoic collisions involving the Amazon and SĂŁo Francisco
paleocontinents and the ParanĂĄ continental block. The BrasĂlia belt is a typical
orocline bended around the WNWâESE striking Pirineus Zone of High Strain
(PZHS) and is comprised of the NE-trending (northern) and SE-trending
(southern) segments. The BrasĂlia dome is an NâS elliptical structural window
situated in the center of the belt, at the eastern end of the PZHS. It evidences
Diâ Dâ and DâÉŽ shortenings (~ 750â590 Ma) due to ocean closure and
Amazon- SĂŁo Francisco collision following a WNWâESE path, and
demonstrates similar evolution for both segments of the belt. However, in the
southern segment, DââDâ structures are deformed by shortening in the SW-NE
direction (DâS). New data demonstrating DââDâ and DâÉŽ tectonites deformed
by DâS struc- tures in the area close to the dome's SW margin and SE of the
PZHS support understanding the BrasĂlia belt and oroclinal bending as a
consequence of the collision of two (Amazon and SĂŁo Francisco) irregular
continental margins leading to separation-rotation of the ParanĂĄ block from the
Amazon paleocontinent and the ParanĂĄ-SĂŁo Francisco collision
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