474 research outputs found
Genotypic diversity, reproductive strategies, and natural selection in non-native populations of Mimulus guttatus
The success of non-native species exposed to environmental conditions may depend on how the species adapt to new conditions. For this reason, non-native species offer the opportunity to understand evolutionary mechanisms such as natural selection that can promote adaptive evolution in new conditions, and also to investigate whether intraspecific admixture may serve as a stimulus for invasion by increasing fitness or a cost to fitness due to outbreeding depression. In addition, high performance of introduced species may be accomplished by a combination of multiple reproductive strategies (e.g., vegetative and sexual reproduction) that can contribute to dispersal and colonization ability. In this research, the herbaceous Mimulus guttatus native to North America and naturalized in United Kingdom (UK) is used to investigate: (1) the level of genotypic (clonal) diversity and genetic variation in non-native populations; (2) the effect of resource availability on the relative investment of sexual and clonal reproduction; (3) the level of phenotypic variation among non-native populations; and (4) patterns of natural selection in its introduced range, and evidence of outbreeding depression in admixed experimental populations.
The genotyping study using single nucleotide polymorphisms reveals that non-native populations show a wide variation of genotypic diversity and that the largest percentage of genetic variation is within populations either in native or introduced ranges. A common garden glasshouse experiment with non-native populations indicates that limited space intensifies the trade-off between sexual and clonal lateral spread, and suggests that populations under limited space conditions (e.g., high-density population) may have to invest less in sexual reproduction than in clonal lateral expansion. A survey of natural M. guttatus populations in UK indicates that production of flowers is favoured in places with low precipitation and high temperatures where production of stolons is limited in M. guttatus. The field experiment with F2 individuals from three crosses between introduced and native populations shows that admixed individuals from introduced populations have higher population growth rate due to increased survival, clonality, and seed production than admixed individuals from introduced and native populations, consistent with outbreeding depression. Selection through sexual fitness favours large floral displays, large vegetative traits, clonal spread, and early flowering in the non-native range. The results presented in this thesis indicate that clonal and sexual reproduction are integrated strategies that contribute to population growth rate, and the alternative investment in both traits in different environments may contribute to the colonization of the species in different habitats. Natural selection has an important role in the naturalization of a highly diverse species such as M. guttatus, and intraspecific admixture is not always beneficial in the introduced range as it may result in outbreeding depression, which further suggests the potential of non-native populations to evolve by adaptation
Algorithms for constrained optimization
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High-performance 16-way Ku-band radial power combiner based on the TE01-circular waveguide mode
This work presents a 16-way Ku-band radial power combiner for high power and high frequency
applications, using the very low loss TE01 circular waveguide mode. The accomplished design shows
an excellent performance: the experimental prototype has a return loss better than 30 dB, with a balance
for the amplitudes of ( 0.15 dB) and ( 2.5 ) for the phases, in a 16.7% fractional bandwidth (2 GHz
centered at 12 GHz). For obtaining these outstanding specifications, required, for instance, in highfrequency
amplification or on plasma systems, a rigorous step-by-step procedure is presented. First, a
high-purity mode transducer has been designed, from the TE10 mode in the rectangular waveguide to
the TE01 mode in the circularwaveguide, with very high attenuation (>50 dB) for the other propagating
and evanescent modes in the circularwaveguide. This transducer has been manufactured and measured
in a back-to-back configuration, validating the design process. Second, an E-plane 16-way radial
power divider has been designed, where the power is coupled from the 16 non-reduced-height radial
standardwaveguides into the TE01 circularwaveguide mode, improving the insertion loss response and
removing the usual tapered transformers of previous designs limiting the power handling. Finally, both
the transducer and the divider have been assembled to make the final radial combiner. The prototype
has been carefully manufactured, showing very good agreement between the measurements and the
full-wave simulationsThe authors would like to thank INMEPRE S.A., the diligence
in the manufacturing process. This work was supported
by the Spanish government under Grant (ADDMATE) No.
TEC2016-76070-C3-1/2-R (AEI/FEDER/UE) and the program
of Comunidad de Madrid S2013/ICE-3000 (SPADERADARCM
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Trump-induced anxiety among Latina/os
During the 2016 election, Donald Trump castigated unauthorized immigrants as “murderers and rapists.” During his presidency, he continued the use of this rhetoric, explicitly linking unauthorized migrants to threatening narratives. Here, we consider three questions: Did Donald Trump and his immigration positions serve as an “anxiety trigger” for Latina/os? Are individuals with contextually stigmatized attributes especially sensitive to Trump and his policy proposals? Is Spanish language itself, an attribute negatively stigmatized in the context of the immigration issue, sufficient to increase deportation anxiety? Utilizing survey experiments of Latina/os, we demonstrate that exposure to a Trump immigration cue is sufficient to increase anxiety about deportation. We also demonstrate that stigmatized attributes predict anxiety, but do not moderate the effect of the Trump cue. Lastly, we provide evidence that survey language affects anxiety among Latina/os. In Studies 1 (n = 736) and 2 (n = 1,040), we show that exposure to information about Trump’s immigration agenda significantly increases reports about deportation anxiety. In Study 3 (n = 1,734), we show that the Trump exposure condition induces heightened anxiety but that Latina/o attributes (language proficiency and use, immigration status, assessed phenotype) and identity strength have an independent effect on deportation anxiety. In Study 4 (n = 775), we randomized bilingual respondents into Spanish or English language survey protocols and found that comparable bilinguals exposed to Spanish language report higher levels of anxiety compared to English-language survey takers
Rendimento de suco e teor de sólidos solúveis totais em genótipos de maracujazeiro amarelo.
Para garantir a sustentabilidade da cultura do maracujazeiro na Amazônia são imprescindíveis pesquisas buscando o desenvolvimento de variedades que apresentem frutos com características desejáveis para a agroindústria. Este trabalho objetivou avaliar o rendimento de suco e teor de sólidos solúveis totais de frutos em genótipos de maracujazeiro. O estudo foi conduzido em seis genótipos de maracujazeiro. Com cinco híbridos CPATU casca fina: CCF (161/82); CCF (136/82); CCF (136/73); CCF (73/161); CCF (161/136), além da variedade comercial Golden Star. A avaliação foi efetuada em vinte frutos por genótipo. As características avaliadas foram: massa, comprimento e diâmetro do fruto, espessura da casca, rendimento de suco e teor de sólidos solúveis totais. O experimento foi conduzido em delineamento inteiramente casualizado com seis tratamentos e quatro repetições de cinco frutos por parcela. Verificou-se que, com relação aos dados morfométricos, como massa, comprimento e largura do fruto, e espessura da casca, a variedade Golden Star foi superior em relação aos cinco híbridos CCF. Contudo, apesar da superioridade no tamanho de frutos, o rendimento de suco foi baixo (34%). Os híbridos apresentaram médias menores para a morfometria do fruto, entretanto tiveram bom rendimento de suco, de 49 a 53%. Portanto, para as condições avaliadas todos os cinco híbridos CCF são indicados para uso na agroindústria.PIBIC-2011
Curvature singularity of the distributional BTZ black hole geometry
For the non-rotating BTZ black hole, the distributional curvature tensor
field is found. It is shown to have singular parts proportional to a
-distribution with support at the origin. This singularity is related,
through Einstein field equations, to a point source. Coordinate invariance and
independence on the choice of differentiable structure of the results are
addressed.Comment: Latex, 7 page
Caracterização morfológica da flor do camucamuzeiro.
Trabalhos feitos sobre a biologia floral da flor do camucamuzeiro consideraram a espécie com alogamia facultativa, não obrigatória, aceitando a geitonogamia, podendo ainda ser polinizada pelo vento. Estudos de morfologia floral são utilizados em pesquisas para ajudar na compreensão da relação entre estruturas reprodutivas e os polinizadores, além da diferenciação entre genótipos da mesma espécie. O trabalho teve como objetivo realizar a caracterização morfométrica em flores de camucamuzeiro, visando o estabelecimento de descritores morfológicos para a espécie. O estudo foi realizado em flores de dez progênies estabelecidas no BAG Camu-camu. Foram caracterizadas as seguintes estruturas: número de estames, comprimento do estilete e o comprimento do pedicelo. Houve variação em todas as estruturas florais avaliadas, com destaque para o número de estames. As progênies apresentaram flores com média de 126,8 estames. As matrizes CPATU-05 e CPATU-21 diferiram das demais com 163,1 e 162,1 estames, respectivamente. Para o comprimento do estilete, a progênie CPATU-5 teve a maior média, (1,16 cm). Com relação ao tamanho do pedicelo, a progênie CPATU-20 apresentou flores com a maior média (0,38 cm). A caracterização morfométrica das flores de camucamuzeiro permite a identificação de ampla variabilidade genética entre as progênies estabelecidas no BAG- Camu-camu. O número de estame e o comprimento do estilete podem ser utilizados como descritores morfológicos visando à diferenciação entre acessos de camucamuzeiro.PIBIC-2011
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