245 research outputs found
Diversidade molecular entre populações de Spodoptera frugiperda no Brasil avaliada por marcadores AFLP.
O objetivo deste trabalho foi avaliar a diversidade molecular, por meio de marcadores AFLP, de seis populações de Spodoptera frugiperda coletadas na cultura do milho, em diferentes regiões geográficas do Brasil. O DNA foi extraído de lagartas de quarto instar, e as reações de AFLP foram realizadas com sete combinações de oligonucleotídeos iniciadores. A partir das seis populações de S. frugiperda estudadas, foi identificado um grupo principal formado por três populações geneticamente mais relacionadas. As populações de S. frugiperda analisadas mostram alta variabilidade genética, com máximo de 58% de similaridade
Characterization of meloidogyne species from irrigated rice in southern Brazil.
Edição dos Proceedings do 6th International Congress of Nematology, Cape Town, South Africa, May 2014
Human origins in Southern African palaeo-wetlands? Strong claims from weak evidence
Attempts to identify a ‘homeland’ for our species from genetic data are widespread in the academic literature. However, even when putting aside the question of whether a ‘homeland’ is a useful concept, there are a number of inferential pitfalls in attempting to identify the geographic origin of a species from contemporary patterns of genetic variation. These include making strong claims from weakly informative data, treating genetic lineages as representative of populations, assuming a high degree of regional population continuity over hundreds of thousands of years, and using circumstantial observations as corroborating evidence without considering alternative hypotheses on an equal footing, or formally evaluating any hypothesis. In this commentary we review the recent publication that claims to pinpoint the origins of ‘modern humans’ to a very specific region in Africa (Chan et al., 2019), demonstrate how it fell into these inferential pitfalls, and discuss how this can be avoided
Aedes albopictus bionomics data collection by citizen participation on procida island, a promising mediterranean site for the assessment of innovative and community-based integrated pest management methods
In the last decades, the colonization of Mediterranean Europe and of other temperate regions by Aedes albopictus created an unprecedented nuisance problem in highly infested areas and new public health threats due to the vector competence of the species. The Sterile Insect Technique (SIT) and the Incompatible Insect Technique (IIT) are insecticide-free mosquito-control methods, relying on mass release of irradiated/manipulated males, able to complement existing and only partially effective control tools. The validation of these approaches in the field requires appropriate experimental settings, possibly isolated to avoid mosquito immigration from other infested areas, and preliminary ecological and entomological data. We carried out a 4-year study in the island of Procida (Gulf of Naples, Italy) in strict collaboration with local administrators and citizens to estimate the temporal dynamics, spatial distribution, and population size of Ae. albopictus and the dispersal and survival of irradiated males. We applied ovitrap monitoring, geo-spatial analyses, mark-release-recapture technique, and a citizen-science approach. Results allow to predict the seasonal (from April to October, with peaks of 928-9,757 males/ha) and spatial distribution of the species, highlighting the capacity of Ae. albopictus population of Procida to colonize and maintain high frequencies in urban as well as in sylvatic inhabited environments. Irradiated males shown limited ability to disperse (mean daily distance travelled <60m) and daily survival estimates ranging between 0.80 and 0.95. Overall, the ecological characteristics of the island, the acquired knowledge on Ae. albopictus spatial and temporal distribution, the high human and Ae. albopictus densities and the positive attitude of the resident population in being active parts in innovative mosquito control projects provide the ground for evidence-based planning of the interventions and for the assessment of their effectiveness. In addition, the results highlight the value of creating synergies between research groups, local administrators, and citizens for affordable monitoring (and, in the future, control) of mosquito populations
Paleogenomic Evidence for Multi-generational Mixing between Neolithic Farmers and Mesolithic Hunter-Gatherers in the Lower Danube Basin
The transition from hunting and gathering to farming involved profound cultural and technological changes. In Western and Central Europe, these changes occurred rapidly and synchronously after the arrival of early farmers of Anatolian origin [1-3], who largely replaced the local Mesolithic hunter-gatherers [1, 4-6]. Further east, in the Baltic region, the transition was gradual, with little or no genetic input from incoming farmers [7]. Here we use ancient DNA to investigate the relationship between hunter-gatherers and farmers in the Lower Danube basin, a geographically intermediate area that is characterized by a rapid Neolithic transition but also by the presence of archaeological evidence that points to cultural exchange, and thus possible admixture, between hunter-gatherers and farmers. We recovered four human paleogenomes (1.1× to 4.1× coverage) from Romania spanning a time transect between 8.8 thousand years ago (kya) and 5.4 kya and supplemented them with two Mesolithic genomes (1.7× and 5.3×) from Spain to provide further context on the genetic background of Mesolithic Europe. Our results show major Western hunter-gatherer (WHG) ancestry in a Romanian Eneolithic sample with a minor, but sizeable, contribution from Anatolian farmers, suggesting multiple admixture events between hunter-gatherers and farmers. Dietary stable-isotope analysis of this sample suggests a mixed terrestrial/aquatic diet. Our results provide support for complex interactions among hunter-gatherers and farmers in the Danube basin, demonstrating that in some regions, demic and cultural diffusion were not mutually exclusive, but merely the ends of a continuum for the process of Neolithization.This research was supported by a European Research Council (ERC) Starting Grant (ERC-2010-StG 263441) to R.P. G.G.-F. was also supported by MSC Individual Fellowship (NeoGenHeritage, grant no. 655478). E.R.J. was supported by a Herchel Smith Research Fellowship. M.H. and A.M. were supported by ERC consolidator grants 310763 GeneFlow and 647797 LocalAdaptation, respectively. V.S. was supported by the Gates Cambridge Trust. The work of C.L. was undertaken through the Partnerships in Priority Areas Program PN II, developed with the support of MEN-UEFISCDI (project no. PN-II-PTPCCA-2013-4-2302). A.G.-D. is supported by the research project BIOGEOS (CGL2014-57209-P) of the Spanish MINECO. The research of P.A., M.D.G., and L.D. on Los Canes is currently supported by the project CoChange (HAR2014-51830-P) of the Spanish State Plan for R+D+i (MINECO)
Seletividade de herbicidas à cultura da erva-mate.
A erva-mate (Ilex paraguariensis St. Hil.) é uma espécie florestal arbórea nativa da América do Sul. Dentre os fatores que afetam o desenvolvimento das plantas, a interferência por plantas daninhas é um dos mais importantes. Nesse sentido o objetivo desse trabalho foi avaliar a seletividade de herbicidas em plantas de erva-mate de um e dois anos de idade. O experimento foi desenvolvido em casa de vegetação, com delineamento inteiramente casualizado, com arranjo fatorial 2 x 18, com quatro repetições. O fator A foi composto por plantas de erva-mate com 1 e 2 anos de idade, enquanto o fator B era composto por testemunha; clethodim+haloxifop (72+36); imazethapyr (100); chlorimuron (17,5); metsulfuron (6); nicosulfuron (45); nicosulfuron safener (60); diclosulam (25,2); atrazine+s-metalochlor (1295+805); bentazone (720); diquat (400); saflufenacil (24,5); fomesafen (250); oxyfluorfen (720); glyphosate (1440); glufosinate (420); florpyrauxifen (15,93); e fluroxypyr (149,8 g de i.a. ou e.a. ha-1). Foram avaliadas as variáveis fitotoxicidade e altura de plantas. Para a variável altura de plantas os tratamentos não apresentaram diferença estatisticamente significativa. As plantas de 1 ano apresentaram menores níveis de fitotoxicidade quando comparadas às plantas de 2 anos (exceto para glufosinate). Os herbicidas clethodim + haloxifop, imazethapyr e diclosulam apresentaram baixa fitotoxicidade e são uma possibilidade para o uso em erva-mate. Em plantas de 1 ano, todos os inibidores da ALS testados apresentaram baixa fitotoxicidade
Produção de maracujazeiro-amarelo sob diferentes densidades de plantio
O adensamento de plantas em cultivos do maracujazeiro-amarelo é importante por propiciar maior rentabilidade em menor área. O objetivo deste trabalho foi avaliar o efeito de diferentes densidades de plantio na produção, qualidade dos frutos e rentabilidade do maracujazeiro-amarelo. O experimento foi instalado e conduzido em pomar comercial da Fazenda Sant'ana, Município de São Tiago, MG. O delineamento experimental utilizado foi o de blocos casualizados com cinco tratamentos e quatro repetições. Os tratamentos constituíram-se de diferentes espaçamentos na linha de plantio: T1, 1,0 m (3.330 plantas/ha); T2, 1,5 m (2.220 plantas/ha); T3, 2,0 m (1.660 plantas/ha); T4, 3,0 m (1.100 plantas/ha) e T5, 4,0 m (830 plantas/ha). O espaçamento entre linhas foi de 3,0 m em todos os tratamentos. Cada parcela foi constituída de 12 m de comprimento por 3,0 m de largura (36 m²). O plantio foi realizado em outubro de 2001, e a colheita, a partir de abril, estendendo-se até agosto de 2002. A maior produtividade foi estimada em 11,9 t/ha na densidade de 1.841 plantas/ha. O adensamento não altera a qualidade do fruto. A máxima eficiência econômica foi alcançada na densidade de 1.340 plantas/ha, com rentabilidade de R$ 1.321,92/ha
Muscle dysfunction in axial spondylarthritis: the MyoSpA study
Objective We aimed to investigate muscle physical properties, strength, mass, physical performance, and the prevalence of sarcopenia in patients with axial spondylarthritis (axSpA) compared to the healthy controls (HC). Methods We performed a cross-sectional study on 54 participants: 27 patients with axSpA and 27 HC, matched by age, gender, and level of physical activity. Muscle physical properties (stiffness, tone and elasticity), muscle strength (five-times sit-to-stand [5STS] test), muscle mass, physical performance (measured through gait speed) and sarcopenia were compared between the groups. Linear regression models were conducted allowing adjustment for relevant variables. Results Patients with axSpA (mean age 36.5 (SD 7.5) years, 67% males, mean disease duration 6.5 (3.2) years) had no significant difference in segmental muscle stiffness, tone or elasticity, compared with the HC, despite showing a slight numerically higher lower lumbar (L3-L4) stiffness [median 246.5 (IQR 230.5–286.5) vs. 232.5 (211.0–293.5), p=0.38]. No participants presented sarcopenia. Patients with axSpA, compared to the HC, had lower total strength [B=1.88 (95% CI 0.43;3.33)], as well as lower strength in the upper (B= -17.02 (-27.33;-6.70)] and lower limbs [B= -11.14 (-18.25;-4.04)], independently of muscle physical properties. Patients had also significantly lower gait speed than the HC [B= -0.11 (-0.21;-0.01)], adjusted for muscle mass, strength and muscle physical properties. Conclusion Young axSpA patients with a relatively short disease duration presented similar segmental muscle physical properties as the HC and had no sarcopenia. Patients with axSpA had reduced physical performance and lower strength compared to the HC, despite normal muscle mass, suggesting a possible muscle dysfunction. Gait characteristics may be a potential biomarker of interest in axSpA.publishersversionpublishe
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