Estimating Economically Optimal Levels of Nitrogen Fertilizer in No-Tillage Continuous Corn

[Abstract:] Stochastic plateau production functions provide improved fertilizer recommendations based on multi-year agronomic experiments where weather and other stochastic variables change over time. This research assesses the profitability of no-tillage corn production in northeastern Colorado and determines economically optimal nitrogen fertilizer rates. It also proposes an alternative parameterization of the linear response stochastic plateau model which provides a robustness check against traditional parameterizations. Results show the current use of nitrogen fertilizer in the area exceeds estimated economically optimal levels. This suggests that a reduction in nitrogen use could increase expected profits and simultaneously reduce environmental costs.This work was supported by Virginia Tech Cooperative Agreement Number 58-3012-7-007 with USDA/ARS; and by Hatch Project VA 136247 Regional project NC-1034.Estados Unidos. Virginia Tech Cooperative Agreement; 58-3012-7-007Estados Unidos. Hatch Project VA 136247 Regional project NC-103

Root microbiome modulates plant growth promotion induced by low doses of glyphosate

Glyphosate is a commonly used herbicide with a broad action spectrum. However, at sublethal doses, glyphosate can induce plant growth, a phenomenon known as hormesis. Most glyphosate hormesis studies have been performed under microbe-free or reduced-microbial-diversity conditions; only a few were performed in open systems or agricultural fields, which include a higher diversity of soil microorganisms. Here, we investigated how microbes affect the8 hormesis induced by low doses of glyphosate. To this end, we used Arabidopsis thaliana and a well-characterized synthetic bacterial community of 185 strains (SynCom) that mimics the root-associated microbiome of Arabidopsis. We found that a dose of 3.6 x 10-6 g acid equivalent/liter (low dose of glyphosate, or LDG) produced an ~14% increase in the shoot dry weight (i.e., hormesis) of uninoculated plants. Unexpectedly, in plants inoculated with the SynCom, LDG reduced shoot dry weight by 17%. We found that LDG enriched two Firmicutes and two Burkholderia strains in the roots. These specific strains are known to act as root growth inhibitors (RGI) in monoassociation assays. We tested the link between RGI and shoot dry weight reduction in LDG by assembling a new synthetic community lacking RGI strains. Dropping RGI strains out of the community restored growth induction by LDG. Finally, we showed that individual RGI strains from a few specific phyla were sufficient to switch the response to LDG from growth promotion to growth inhibition. Our results indicate that glyphosate hormesis was completely dependent on the root microbiome composition, specifically on the presence of root growth inhibitor strains

Why do herbivorous mites suppress plant defenses?

Plants have evolved numerous defensive traits that enable them to resist herbivores. In turn, this resistance has selected for herbivores that can cope with defenses by either avoiding, resisting or suppressing them. Several species of herbivorous mites, such as the spider mites Tetranychus urticae and Tetranychus evansi, were found to maximize their performance by suppressing inducible plant defenses. At first glimpse it seems obvious why such a trait will be favored by natural selection. However, defense suppression appeared to readily backfire since mites that do so also make their host plant more suitable for competitors and their offspring more attractive for natural enemies. This, together with the fact that spider mites are infamous for their ability to resist (plant) toxins directly, justifies the question as to why traits that allow mites to suppress defenses nonetheless seem to be relatively common? We argue that this trait may facilitate generalist herbivores, like T. urticae, to colonize new host species. While specific detoxification mechanisms may, on average, be suitable only on a narrow range of similar hosts, defense suppression may be more broadly effective, provided it operates by targeting conserved plant signaling components. If so, resistance and suppression may be under frequency-dependent selection and be maintained as a polymorphism in generalist mite populations. In that case, the defense suppression trait may be under rapid positive selection in subpopulations that have recently colonized a new host but may erode in relatively isolated populations in which host-specific detoxification mechanisms emerge. Although there is empirical evidence to support these scenarios, it contradicts the observation that several of the mite species found to suppress plant defenses actually are relatively specialized. We argue that in these cases buffering traits may enable such mites to mitigate the negative side effects of suppression in natural communities and thus shield this trait from natural selection

Enfermedad viral por virus SARS -CoV2 en niños. Presentación de un caso

Introduction: In general, the affectation of the SARS-CoV2 virus in children is mild or asymptomatic, otherspresent symptoms that can be diverse, in some they require admission and others in a smaller percentage it isnecessary to enter intensive care, the symptoms, sometimes with Abdominal disorders join other frequentsymptoms of the disease that can be confused with other pathologies. Objective: To differentiate the clinical expressions of the SARS-CoV2 virus in the pediatric age, with otherviral infections. Material and methods: Retrospective descriptive study presenting a clinical case. Results: We present a case of an 8-year-old girl who did not present a cough in her symptoms and that thesymptoms of joint pain, headache, diarrhea, vomiting, high fever, were the fundamental in her clinical picture,these are also shared with Dengue , Elevated IgM 126 (0-0.99), CRP 4.05 mg / L (0-0.9), with mild neutrophilia82.5% (55-70) and lymphopenia 12.5% (17-45) were detected in the hematic biometry, Lactic Dehydrogenase(LDH) 232 U / L (100-190), normal electrolytes, Aspartate Amino Trasferase (TGO) 82 U / L (12-37), normal abdominal ECHO, negative dengue IgM, after 5 days of admission, of a remarkable improvementis discharged. Conclusions: Taking into account the incidence of Dengue in your place of residence, a differential diagnosiswith the SARS-CoV2 virus plays a fundamental role, because as this case shows us, it can have similar symptoms,so that an adequate clinical criterion and performance complementary, they will give us the opportunityto make a correct diagnosis.Introducción: En general la afectación del virus SARS -CoV2 en niños es leve o asintomática, otros presentansintomatología que puede ser diversa, en algunos requiere de ingreso y otros en un porciento menor es necesarioingresar en cuidados intensivos, la sintomatología, en ocasiones con trastornos abdominales se unen aotros síntomas frecuentes de la enfermedad que pueden ser confundidas con otras patologías. Objetivo: Diferenciar las expresiones clínicas del virus SARS -CoV2 en la edad pediátrica, con otras infeccionesvirales. Material y métodos: Estudio descriptivo retrospectivo presentación de caso clínico. Resultados: Presentamos un caso de una niña de 8 años que en su sintomatología no presentaba tos y que lossíntomas de dolores articulares, cefalea, diarreas, vómitos, fiebre elevada, eran lo fundamental en su cuadroclínico, estos también se comparten con el Dengue, se detectó IgM elevada 126 ( 0-0.99), PCR 4.05 mg/L(0-0.9), con una leve neutrofilia 82.5 % (55-70) y linfopenia 12.5% (17-45) en la biometría hemática, DeshidrogensaLáctica ( LDH) 232 U/L (100-190) , electrolitos normales, Aspartato Amino Trasferasa ( TGO) 82U/L ( 12-37), ECO abdominal normal, IgM dengue negativo, después de 5 días del ingreso, de una notablemejoría es dada de alta. Conclusiones: Teniendo en cuenta la incidencia del Dengue en su lugar de residencia juega un papel fundamentalrealizar el diagnostico diferencial con el virus SARS -CoV2, pues como este caso nos demuestra puedetener sintomatología similar, por lo que un criterio clínico adecuado y la realización de complementarios,nos darán la oportunidad de realizar un diagnóstico correct

Limitations of selective deltamethrin application for triatomine control in central coastal Ecuador

<p>Abstract</p> <p>Background</p> <p>This year-long study evaluated the effectiveness of a strategy involving selective deltamethrin spraying and community education for control of Chagas disease vectors in domestic units located in rural communities of coastal Ecuador.</p> <p>Results</p> <p>Surveys for triatomines revealed peridomestic infestation with <it>Rhodnius ecuadoriensis </it>and <it>Panstrongylus howardi</it>, with infestation indices remaining high during the study (13%, 17%, and 10%, at initial, 6-month, and 12-month visits, respectively), which indicates a limitation of this strategy for triatomine population control. Infestation was found 6 and 12 months after spraying with deltamethrin. In addition, a large number of previously vector-free domestic units also were found infested at the 6- and 12-month surveys, which indicates new infestations by sylvatic triatomines. The predominance of young nymphs and adults suggests new infestation events, likely from sylvatic foci. In addition, infection with <it>Trypanosoma cruzi </it>was found in 65%, 21% and 29% at initial, 6-month and 12-month visits, respectively. All parasites isolated (n = 20) were identified as TcI.</p> <p>Conclusion</p> <p>New vector control strategies need to be devised and evaluated for reduction of <it>T. cruzi </it>transmission in this region.</p

Ecological factors related to the widespread distribution of sylvatic Rhodnius ecuadoriensis populations in southern Ecuador

<p>Abstract</p> <p>Background</p> <p>Chagas disease transmission risk is a function of the presence of triatomines in domestic habitats. <it>Rhodnius ecuadoriensis </it>is one of the main vectors implicated in transmission of <it>Trypanosoma cruzi </it>in Ecuador. This triatomine species is present in domestic, peridomestic and sylvatic habitats in the country. To determine the distribution of sylvatic populations of <it>R. ecuadoriensis </it>and the factors related to this distribution, triatomine searches were conducted between 2005 and 2009 in southern Ecuador.</p> <p>Methods</p> <p>Manual triatomine searches were conducted by skilled bug collectors in 23 communities. Sylvatic searched sites were selected by a) directed sampling, where microhabitats were selected by the searchers and b) random sampling, where sampling points where randomly generated. Domiciliary triatomine searches were conducted using the one man-hour method. Natural trypanosome infection was determined by microscopic examination and PCR. Generalized linear models were used to test the effect of environmental factors on the presence of sylvatic triatomines.</p> <p>Results</p> <p>In total, 1,923 sylvatic individuals were collected representing a sampling effort of 751 man-hours. Collected sylvatic triatomines were associated with mammal and bird nests. The 1,219 sampled nests presented an infestation index of 11.9%, a crowding of 13 bugs per infested nest, and a colonization of 80% of the nests. Triatomine abundance was significantly higher in squirrel (<it>Sciurus stramineus</it>) nests located above five meters from ground level and close to the houses. In addition, 8.5% of the 820 examined houses in the same localities were infested with triatomines. There was a significant correlation between <it>R. ecuadoriensis </it>infestation rates found in sylvatic and synanthropic environments within communities (<it>p </it>= 0.012). Parasitological analysis revealed that 64.7% and 15.7% of the sylvatic bugs examined (n = 300) were infected with <it>Trypanosoma cruzi </it>and <it>T. rangeli </it>respectively, and 8% of the bugs presented mixed infections.</p> <p>Conclusions</p> <p>The wide distribution of sylvatic <it>R. ecuadoriensis </it>populations may jeopardize the effectiveness of control campaigns conducted to eliminate domestic populations of this species. Also, the high <it>T. cruzi </it>infection rates found in sylvatic <it>R. ecuadoriensis </it>populations in southern Ecuador could constitute a risk for house re-infestation and persistent long-term Chagas disease transmission in the region.</p

Integration of miRNA and mRNA expression profles reveals microRNA-regulated networks during muscle wasting in cardiac cachexia

Cardiac cachexia (CC) is a common complication of heart failure (HF) associated with muscle wasting and poor patient prognosis. Although different mechanisms have been proposed to explain muscle wasting during CC, its pathogenesis is still not understood. Here, we described an integrative analysis between miRNA and mRNA expression profiles of muscle wasting during CC. Global gene expression profiling identified 1,281 genes and 19 miRNAs differentially expressed in muscle wasting during CC. Several of these deregulated genes are known or putative targets of the altered miRNAs, including miR-29a-3p, miR-29b-3p, miR-210-5p, miR-214, and miR-489. Gene ontology analysis on integrative mRNA/miRNA expression profiling data revealed miRNA interactions affecting genes that regulate extra-cellular matrix (ECM) organization, proteasome protein degradation, citric acid cycle and respiratory electron transport. We further identified 11 miRNAs, including miR-29a-3p and miR-29b-3p, which target 21 transcripts encoding the collagen proteins related to ECM organization. Integrative miRNA and mRNA global expression data allowed us to identify miRNA target genes involved in skeletal muscle wasting in CC. Our functional experiments in C2C12 cells confirmed that miR-29b down-regulates collagen genes and contributes to muscle cell atrophy. Collectively, our results suggest that key ECM-associated miRNAs and their target genes may contribute to CC in HF

Diagnóstico y evolución de la actividad turística bajo los efectos del Covid19 en el destino Sucre, Ecuador

The investigative work aimed to diagnose the current situation regarding the perception of visitors through market research of the tourist destination in Sucre, identifying the strengths and weaknesses tending to work from the public and private actors for the governance of the destination. The qualitative and quantitative approach was used through a descriptive study, as a research technique the survey was applied to a sample of 382 visitors. The field research used the SPSS 22.0 statistical program to measure reliability, whose value was 0.808 and the validity generated 0.71 as a result, which is acceptable. As a result, it was known that there is a high level of visitors that figured 50%. It is concluded that Sucre is a destination recognized for its spas, receiving an evaluation of 82% and a level of satisfaction that drops to 40% by the agents of the tourist services. This preponderant perspective will help for subsequent research, regarding new ventures, promoting the investigative work of the new professionals that the university graduates each year and who respond to the integration of substantive processes such as research, outreach and academia from the projects. operant investigators.El trabajo investigativo tuvo como objetivo diagnosticar la situación actual referente a la percepción de los visitantes a través de una investigación de mercados del destino turístico en Sucre, identificando las fortalezas y debilidades tendientes a trabajarse desde los actores público y privado para la gobernanza del destino. Se empleó el enfoque cualitativo y cuantitativo mediante un estudio descriptivo, como técnica investigativa se aplicó la encuesta a una muestra de 382 visitantes. La investigación de campo manejó el programa estadístico SPSS 22.0 para medir la fiabilidad, cuyo valor fue de 0.808 y, la validez generó como resultado 0.71, la cual es aceptable. Como resultado se conoció que existe un alto nivel de visitantes que figuró el 50%. Se concluye que Sucre es un destino reconocido por sus balnearios, recibiendo una valoración de 82% y un nivel de satisfacción que baja al 40% por los agentes de los servicios turísticos. Esta perspectiva preponderante ayudará para investigaciones posteriores, en lo concerniente a nuevos emprendimientos   potenciando los trabajos investigativos de los nuevos profesionales que la universidad gradúa cada año y que responden a la integración de los procesos sustantivos como es la investigación, vinculación y la academia desde los proyectos investigativos operantes

Interlaboratory exercise for the analysis of carotenoids and related compounds in dried mango fruit (Mangifera indica L.)

An interlaboratory comparison was done for the analysis of carotenoids in freeze-dried mango. The study was performed from July to September 2018. Mango fruit was freeze-dried, homogenized, and packaged under vacuum conditions in portions of 6 g (test sample). Two test samples were sent to the participating laboratories for analysis. Laboratory results were rated using Z-scores in accordance with ISO 13528 and ISO 17043. The standard deviation for proficiency assessment (also called target standard deviation) was determined using a modified Horwitz function and varied between 10% and 25%, depending on the analyte. Out of 14 laboratories from 10 different countries, 9 laboratories (64%) obtained a satisfactory performance (Z ≤ 2) for the analysis of β-carotene. While for 7 laboratories that analyzed α-carotene, (9Z)-β-carotene, β-cryptoxanthin, and zeaxanthin, 4 laboratories (57%) obtained a satisfactory performance. However, only 2 laboratories out of 7 (29%) obtained a satisfactory performance for lutein. Based on the comparability of the analytical results, this study concludes that freeze-dried mango pulp can be used as a reference material for the analysis of α and β-carotene, (9Z)-β-carotene, β-cryptoxanthin, and zeaxanthin by applying different analytical procedures for their extraction and quantification