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Blandon-Diaz J.U.,National University of Agriculture at Nicaragua | Blandon-Diaz J.U.,Swedish University of Agricultural Sciences | Forbes G.A.,International Potato Center | Andrade-Piedra J.L.,CIP | Yuen J.E.,Agricultural University of Ecuador
Plant Disease | Year: 2011

In this study, the adequacy of the late blight simulation model LATEBLIGHT (version LB2004) was evaluated under Nicaraguan conditions. During 2007 to 2008, five field experiments were conducted in three potato-production regions in northern Nicaragua. Two susceptible ('Cal White' and 'Granola') and one resistant ('Jacqueline Lee') potato cultivars were evaluated without use of fungicides and with three application intervals (4, 7, and 14 days) of the fungicide chlorothalonil. The simulation model was considered adequate because it accurately predicted high disease severity in susceptible cultivars without fungicide protection, and demonstrated a decrease in the disease progress curves with additional fungicide applications, similar to that observed in the plots. The model also generally predicted inadequate fungicide control, even with a 4-day spray interval, which also occurred in the field. Lack of adequate fungicide protection would indicate the need for cultivars with higher levels of durable resistance, and that farmers should consider more effective fungicides applications (higher dosages or different chemistries) if susceptible cultivars are used. © 2011 The American Phytopathological Society.


Freile J.F.,Fundacion Numashir | Salas J.A.,University of Guayaquil | Solano-Ugalde A.,Fundacion Imaymana | Navarrete R.,Agricultural University of Ecuador
Check List | Year: 2012

We report the first confirmed evidence of a feral introduced population of Brotogeris versicolorus (Statius Müller, 1776) in Guayaquil city, Ecuador, as part of the World Parrot Count led by City Parrots. A total of 216 individuals were counted, at two places within the city, but no direct evidence of breeding was found. A previously unpublished photograph suggesting nesting activity is also presented, along with brief comments on previous and additional observations and the conservation implications of this recently established feral species. © 2012 Check List and Authors.


PubMed | Oklahoma State University and Agricultural University of Ecuador
Type: | Journal: Journal of virological methods | Year: 2016

Rose rosette disease is a disorder associated with infection by Rose rosette virus (RRV), a pathogen of roses that causes devastating effects on most garden cultivated varieties, and the wild invasive rose especially Rosa multiflora. Reliable and sensitive detection of this disease in early phases is needed to implement proper control measures. This study assesses a single primer-set based detection method for RRV and demonstrates its application in three different chemistries: Endpoint RT-PCR, TaqMan-quantitative RT-PCR (RT-qPCR) and SYBR Green RT-qPCR with High Resolution Melting analyses. A primer set (RRV2F/2R) was designed from consensus sequences of the nucleocapsid protein gene p3 located in the RNA 3 region of RRV. The specificity of primer set RRV2F/2R was validated in silico against published GenBank sequences and in-vitro against infected plant samples and an exclusivity panel of near-neighbor and other viruses that commonly infect Rosa spp. The developed assay is sensitive with a detection limit of 1fg from infected plant tissue. Thirty rose samples from 8 different states of the United States were tested using the developed methods. The developed methods are sensitive and reliable, and can be used by diagnostic laboratories for routine testing and disease management decisions.


Mora J.R.,Agricultural University of Ecuador | Mora J.R.,Venezuelan Institute for Scientific Research | Lezama J.,University of the East Venezuela | Cordova-Sintjago T.C.,University of Florida | Chuchani G.,Venezuelan Institute for Scientific Research
Molecular Physics | Year: 2015

The mechanisms of the gas-phase thermal decomposition of bicyclo[2.2.1]heptadiene and 3,7,7-trimethylbicyclo[2.2.1]hept-2-ene were examined by density functional theory calculations with the hybrid functionals: B3LYP, CAM-B3LYP, MPW1PW91, and PBEPBE. Reasonable agreements were found between theoretical and experimental values with the B3LYP hybrid functional. Three molecular concerted pathways for bicyclo[2.2.1]heptadiene decomposition are proposed. The retro-Diels-Alder (retro-DA) pathway yields cyclopentadiene and acetylene through a nearly synchronous transition state structure (Sy=0.97). The other two reaction channels are stepwisewith a common step with the formation of the intermediate bicyclo[4.1.0] heptadiene. This reaction is dominated by C-C bond breaking leading to the methylene migration by an early transition state in the reaction coordinate (Sy = 0.91). The rearrangements of the latter intermediate producing toluene were also studied. The retro-DA elimination of 3,7,7-trimethylbicyclo[2.2.1]hept-2-ene gives 1,5,5-trimethyl-cyclopenta-1,3-diene in a less synchronous process (Sy = 0.77). This fact may be due to the electronic effects of the methyl substituent. The latter product is unstable and undergoes methyl migrations to give a more stable isomer 1,2,3-trimethylcyclopenta-1,3-diene. The stepwise mechanism for the retro-DA reaction through a biradical intermediate appears to be unfavourable because the barrier is bigger than that for the concerted reaction. © 2015 Taylor & Francis.


Aguirre W.E.,DePaul University | Shervette V.R.,University of South Carolina | Navarrete R.,Agricultural University of Ecuador | Calle P.,ESPOL Polytechnic University | Agorastos S.,State University of New York at Stony Brook
Copeia | Year: 2013

Little is known about the freshwater fishes of western Ecuador despite serious environmental threats, including the creation of large artificial impoundments Phenotypic and genetic divergence of populations of a large predatory fish, Hoplias microlepis, is examined in rivers and artificial impoundments of the Guayas River drainage in western Ecuador Despite the recent formation of the impoundments (∼20 years prior to the sampling), H microlepis in these habitats diverged morphologically from river populations Impoundment fish tended to have larger eyes, longer dorsal and caudal fins, and thinner bodies than river fish Classification rates for habitat of origin based on morphometric measures were relatively high (71.7-83.3%), and the magnitude of morphological divergence was substantial when contrasted with divergence from H malabaricus, a congener from eastern Ecuador Frequencies of mtDNA d-loop haplotypes differed significantly among samples Genetic divergence between river samples implies that the genetic structure in the drainage predates the formation of the impoundments The genetic analysis also indicates that the morphological divergence between fish in different habitat types is not likely due to shared ancestry Genetic diversity tended to be higher in the river samples, and the percentage of private alleles was higher in the impoundment populations, which is consistent with rapid population expansion from a limited number of founders in impoundments © 2013 by the American Society of Ichthyologists and Herpetologists.


Mora J.R.,Agricultural University of Ecuador | Mora J.R.,Venezuelan Institute for Scientific Research | Lezama J.,University of the East Venezuela | Cordova-Sintjago T.C.,Florida College | Chuchani G.,Venezuelan Institute for Scientific Research
Molecular Physics | Year: 2015

The mechanisms of the gas-phase thermal decomposition of bicyclo[2.2.1]heptadiene and 3,7,7-trimethylbicyclo[2.2.1]hept-2-ene were examined by density functional theory calculations with the hybrid functionals: B3LYP, CAM-B3LYP, MPW1PW91, and PBEPBE. Reasonable agreements were found between theoretical and experimental values with the B3LYP hybrid functional. Three molecular concerted pathways for bicyclo[2.2.1]heptadiene decomposition are proposed. The retro-Diels–Alder (retro-DA) pathway yields cyclopentadiene and acetylene through a nearly synchronous transition state structure (Sy = 0.97). The other two reaction channels are stepwise with a common step with the formation of the intermediate bicyclo[4.1.0] heptadiene. This reaction is dominated by C–C bond breaking leading to the methylene migration by an early transition state in the reaction coordinate (Sy = 0.91). The rearrangements of the latter intermediate producing toluene were also studied. The retro-DA elimination of 3,7,7-trimethylbicyclo[2.2.1]hept-2-ene gives 1,5,5-trimethyl-cyclopenta-1,3-diene in a less synchronous process (Sy = 0.77). This fact may be due to the electronic effects of the methyl substituent. The latter product is unstable and undergoes methyl migrations to give a more stable isomer 1,2,3-trimethylcyclopenta-1,3-diene. The stepwise mechanism for the retro-DA reaction through a biradical intermediate appears to be unfavourable because the barrier is bigger than that for the concerted reaction. © 2015 Taylor & Francis


Gonzalez de Leon S.,Institute Ecologia Ac | Herrera I.,Agricultural University of Ecuador | Herrera I.,Venezuelan Institute for Scientific Research | Guevara R.,Institute Ecologia Ac
Ecology and Evolution | Year: 2016

Ecological invasions are a major issue worldwide, where successful invasion depends on traits that facilitate dispersion, establishment, and population growth. The nonnative succulent plant Kalanchoe pinnata, reported as invasive in some countries, is widespread in remnants of seasonally dry tropical forest on a volcanic outcrop with high conservation value in east-central Mexico where we assessed its mating system and demographic growth and identified management strategies. To understand its local mating system, we conducted hand-pollination treatments, germination, and survival experiments. Based on the experimental data, we constructed a life-stage population matrix, identified the key traits for population growth, weighted the contributions of vegetative and sexual reproduction, and evaluated management scenarios. Hand-pollination treatments had slight effects on fruit and seed setting, as well as on germination. With natural pollination treatment, the successful germination of seeds from only 2/39 fruit suggests occasional effective natural cross-pollination. The ratios of the metrics for self- and cross-pollinated flowers suggest that K. pinnata is partially self-compatible. Most of the pollinated flowers developed into fruit, but the seed germination and seedling survival rates were low. Thus, vegetative propagation and juvenile survival are the main drivers of population growth. Simulations of a virtual K. pinnata population suggest that an intense and sustained weeding campaign will reduce the population within at least 10 years. Synthesis and applications. The study population is partially self-compatible, but sexual reproduction by K. pinnata is limited at the study site, and population growth is supported by vegetative propagation and juvenile survival. Demographic modeling provides key insights and realistic forecasts on invasion process and therefore is useful to design management strategies. © 2016 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.


Herrera I.,Venezuelan Institute for Scientific Research | Herrera I.,Agricultural University of Ecuador | Ferrer-Paris J.R.,Venezuelan Institute for Scientific Research | Hernandez-Rosas J.I.,Agricultural University of Ecuador | And 2 more authors.
Journal of Arid Environments | Year: 2016

Kalanchoe daigremontiana and Stapelia gigantea are two succulent invasive species with potential impacts on recruitment of native vegetation in a protected area of importance for conservation of arid environments in northern South America. We hypothesized that while K. daigremontiana has the potential for inhibiting recruitment of native plants through allelopathic effects, S. gigantea could facilitate recruitment of nurse-dependent native taxa. To explore these contrasting impacts, we designed a comparative study and a transplant experiment. Density of native seedlings and species richness were significantly lower in patches invaded by K. daigremontiana when compared to patches with native vegetation or invaded by S. gigantea, suggesting that native-seedling recruitment is negatively affected by K. daigremontiana and not affected or facilitated by S. gigantea. The experiment did not generate results concordant with those obtained in the comparative study. Seedlings' recruitment of two selected native species was facilitated by presence of nurse-plants (exotics and natives); however, the magnitude of this effect varied according to the type of nurse-plant, susceptibility to herbivory, and herbivory level. We identify K. daigremontiana as the invasive with top need for management actions, because it has the potential to alter composition and physiognomy of native-plant communities in tropical arid environments. © 2016 Elsevier Ltd.


Aguirre W.,DePaul University | Navarrete R.,Agricultural University of Ecuador | Calle P.,ESPOL Polytechnic University | Sanchez-Garces G.C.,Fundacion Funindes
Check List | Year: 2014

Iotabrycon praecox (Characidae: Stevardiinae) has been reported as endemic to the Guayas River drainage in Western Ecuador since its description in 1973. We collected one specimen of I. praecox in the Santa Rosa River, Santa Rosa drainage, El Oro Province, approximately 144 km south of the Guayas drainage, significantly expanding the known geographic distribution of the species. Given the severe anthropomorphic pressures impacting fishes in Southwestern Ecuador, there is an urgent need to evaluate the present status of I. praecox in the region. © 2014 Check List and Authors.


Rodriguez-Garcia M.A.,King Abdullah University of Science and Technology | Medina-Moreira J.,University of Guayaquil | Lagos-Ortiz K.,Agricultural University of Ecuador | Luna-Aveiga H.,University of Guayaquil | And 2 more authors.
Advances in Intelligent Systems and Computing | Year: 2016

Nowadays organizations should handle a huge amount of both internal and external data from structured, semi-structured, and unstructured sources. This constitutes a major challenge (and also an opportunity) to current Business Intelligence solutions. The complexity and effort required to analyse such plethora of data implies considerable execution times. Besides, the large number of data analysis methods and techniques impede domain experts (laymen from an IT-assisted analytics perspective) to fully exploit their potential, while technology experts lack the business background to get the proper questions. In this work, we present a semantically-boosted platform for assisting layman users in (i) extracting a relevant subdataset from all the data, and (ii) selecting the data analysis technique(s) best suited for scrutinising that subdataset. The outcome is getting better answers in significantly less time. The platform has been evaluated in the music domain with promising results. © Springer International Publishing Switzerland 2016.

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