Evaluating the competitive ability of semi-leafless field pea cultivars

Non-Peer ReviewedField pea (Pisum sativum L.) is an important grain legume in Western Canada. Growers can, however, be reluctant to include pulse crops in their rotation because they are poor competitors with weeds. Developing more competitive field pea cultivars is important to ameliorate weed competition. The identification of competitive cultivars and the traits conferring competitive ability should lead to the development of more competitive field pea cultivars. The objective of this research was to evaluate the ability of semi-leafless field pea cultivars to suppress and withstand weed competition and to identify traits that may confer competitive ability in field pea. Field experiments were conducted in 2012 at Floral, Saskatchewan and St. Albert, Alberta. Fourteen semi-leafless field pea cultivars with divergent pedigree, vine length, seed size, and market classes were seeded at a target density of 75 plants m-2 under weedy and weed-free conditions. Imidazolinone-tolerant wheat (c.v. CDC Imagine) and canola (c.v. 45H73) were planted as pseudo weeds at a target density of 20 plants m-2 in the weedy plots. Variables measured were leaf area index, plant height, pea biomass, weed biomass, pea yield, and weed seed production. Data were subjected to ANOVA using the mixed model procedure in SAS. There was no cultivar by treatment interaction for pea yield at Floral, so cultivars did not differ under treatments. CDC Dakota produced the greatest pea yield and Reward produced the poorest pea yield. CDC Dakota was among the best for pea biomass production at both sites, compared to CDC Leroy, which was among the worst at both sites. CDC Dakota was also among the best for the low weed seed production at Floral. CDC Mozart, CDC Patrick, and Cutlass were among the best at Floral for ability to withstand competition at Floral. While, CDC Dakota, CDC Meadow, and CDC Patrick were among the best for their ability to compete at Floral. At both sites, no correlations were strong enough to show which traits are conferring competitiveness in semi-leafless field pea cultivars

Evaluating the competitive ability of semi-leafless field pea cultivars

Non-Peer ReviewedField pea (Pisum sativum L.) is an important grain legume in Western Canada. Growers can, however, be reluctant to include pulse crops in their rotation because they are poor competitors with weeds. Developing more competitive field pea cultivars is important to mitigate weed competition. The identification of competitive cultivars and the traits conferring competitive ability should lead to the development of more competitive field pea cultivars. The objective of this research was to evaluate the ability of semi-leafless field pea cultivars to suppress and withstand weed competition and to identify traits that may confer competitive ability in field pea. Field experiments were conducted in 2012 and 2013 at Floral, Saskatchewan, Saskatoon, Saskatchewan and St. Albert, Alberta. Fourteen semi-leafless field pea cultivars were seeded at a target density of 75 plants m-2 under weedy and weed-free conditions. Imidazolinone-tolerant wheat (c.v. CDC Imagine) and canola (c.v. 45H73) were planted as pseudo weeds in the weedy plots. There was no cultivar by treatment interaction for all of the measured variables thus, cultivars did not differ in the presence or absence of weed competition. CDC Dakota produced the greatest pea yield and Reward produced the poorest pea yield at Saskatchewan. CDC Dakota and CDC Striker were among the best for pea biomass production at Saskatchewan, compared to Reward, which was among the worst. CDC Centennial and CDC Mozart were significantly better at Saskatchewan for their ability to withstand competition, while CDC Dakota, CDC Patrick, and CDC Meadow were statistically the best in their ability to compete with the pseudo weeds. At Alberta, CDC Striker and CDC Dakota were statistically best in their ability to compete with the pseudo weeds, versus Cooper and Stratus, who were among the poorest. At both Saskatchewan and Alberta, no correlations were strong enough to show which traits are conferring competitiveness in semi-leafless field pea cultivars

Breaking CPT by mixed non-commutativity

The mixed component of the non-commutative parameter \theta_{\mu M}, where \mu = 0,1,2,3 and M is an extra dimensional index may violate four-dimensional CPT invariance. We calculate one and two-loop induced couplings of \theta_{\mu 5} with the four-dimensional axial vector current and with the CPT odd dim=6 operators starting from five-dimensional Yukawa and U(1) theories. The resulting bounds from clock comparison experiments place a stringent constraint on \theta_{\mu 5}, |\theta_{\mu 5}|^{-1/2} > 5\times 10^{11} GeV. The orbifold projection and/or localization of fermions on a 3-brane lead to CPT-conserving physics, in which case the constraints on \theta{\mu 5} are softened.Comment: 4 pages, latex, 1 figur

Models of quintessence coupled to the electromagnetic field and the cosmological evolution of alpha

We study the change of the effective fine structure constant in the cosmological models of a scalar field with a non-vanishing coupling to the electromagnetic field. Combining cosmological data and terrestrial observations we place empirical constraints on the size of the possible coupling and explore a large class of models that exhibit tracking behavior. The change of the fine structure constant implied by the quasar absorption spectra together with the requirement of tracking behavior impose a lower bound of the size of this coupling. Furthermore, the transition to the quintessence regime implies a narrow window for this coupling around $10^{-5}$ in units of the inverse Planck mass. We also propose a non-minimal coupling between electromagnetism and quintessence which has the effect of leading only to changes of alpha determined from atomic physics phenomena, but leaving no observable consequences through nuclear physics effects. In doing so we are able to reconcile the claimed cosmological evidence for a changing fine structure constant with the tight constraints emerging from the Oklo natural nuclear reactor.Comment: 13 pages, 10 figures, RevTex, new references adde

Processos de democracia direta: sim ou não? Os argumentos clássicos à luz da teoria e da prática

Regularmente surgem controvérsias sobre os processos de democracia direta, dos quais os mecanismos mais frequentes são a iniciativa popular, o plebiscito e o referendo. Por um lado, há autores que defendem a posição de que essas instituições tornam o jogo político mais lento, caro, confuso e ilegítimo; outros defendem a posição contrária e argumentam que processos de democracia direta são fundamentais para os cidadãos e a qualidade da democracia. O presente estudo analisa esse tema em torno de sete questões, baseadas em considerações teóricas e pesquisas empíricas: 1. A questão entre o minimalismo e o maximalismo democrático; 2. A concorrência entre maioria e minoria; 3. A concorrência entre as instituições representativas e os processos de democracia direta; 4. A questão da competência dos cidadãos; 5. A questão dos efeitos colaterais dos processos de democracia direta; 6. A questão do tamanho do eleitorado; 7. A questão dos custos dos processos de democracia direta. As sete questões são analisadas a partir de uma revisão bibliográfica que considera tanto fontes nacionais como internacionais. O estudo mostra que os processos de democracia direta podem ser um complemento para as instituições representativas em um sistema democrático. O bom desempenho dos plebiscitos, referendos e iniciativas populares depende tanto da regulamentação destes como também do desempenho das outras instituições políticas e da situação socioeconômica de um país. O estudo permite ampliar e aprofundar o debate sobre processos de democracia direta no Brasil

Sick wings: the effects of the baculovirus AcMNPV on wing development in the speckled wood butterfly, Pararge aegeria

Baculoviruses not only affect resource allocation to growth and reproduction, but they also have the possibility to act on host signalling pathways involved in cell differentiation and thus tissue patterning. Infection typically starts in the insect gut after ingesting virally contaminated food, and the infection will spread to other tissues aided by, for example, metalloproteases. Metalloproteases, such as tolloid, regulate in normal host development the activity of the decapentaplegic (dpp) antagonist short gastrulation (sog). Dpp plays a key role in regulating wing shape, size and wing vein positioning. Overexpression of tolloid in Drosophila pupae results in wing abnormalities, especially in the posterior part of the wing, as it disturbs the balance between sog and dpp levels. It is known in Drosophila that bacteria that produce a number of different metalloproteases in their host, cause similar wing defects as when tolloid is overexpressed. The baculovirus AcMNPV produces the metalloprotease cathepsin (Ac-)v-cath. Cathepsin is not homologous to tolloid, but just as efficient a metalloprotease, and is known in flies to affect wing and leg imaginal discs outgrowth. Nothing is known, however, about how it affects wing shape and wing venation patterning. In this talk I will discuss in detail, at the phenotypic level, how wing development was affected in a series of experiments in which second instar speckled wood (Pararge aegeria) caterpillars were infected with different doses of AcMNPV. The implications of the effects of baculoviruses modulating wing development in natural populations will be discussed

TRPV4 mutations and cytotoxic hypercalcemia in axonal Charcot-Marie-Tooth neuropathies

Objective: To improve understanding of TRPV4-associated axonal Charcot-Marie-Tooth (CMT) neuropathy phenotypes and their debated pathologic mechanism. Methods: A total of 17 CMT2C phenotypic families with vocal cord and diaphragmatic involvement and 36 clinically undifferentiated CMT2 subjects underwent sequencing analysis of the coding region of TRPV4. Functional studies of mutant proteins were performed using transiently transfected cells for TRPV4 subcellular localization, basal and stimulated Ca²⁺ channel analysis, and cell viability assay with or without channel blockade. Results: Two TRPV4 mutations R232C and R316H from 17 CMT2C families were identified in the ankyrin repeat domains. The R316H is a novel de novo mutation found in a patient with CMT2C phenotype. The family with R232C mutation had individuals with and without vocal cord and diaphragm involvement. Both mutant TRPV4 proteins had normal subcellular localization in HEK293 and HeLa cells. Cells transfected with R232C and R316H displayed increased intracellular Ca²⁺ levels and reversible cell death by the TRPV channel antagonist, ruthenium red. Conclusion: TRPV4 ankyrin domain alterations including a novel de novo mutation cause axonal CMT2. Individuals with the same mutation may have nondistinct CMT2 or have phenotypic CMT2C with vocal cord paresis. Reversible hypercalcemic gain-of-function of mutant TRPV4 instead of loss-of-function appears to be pathologically important. The reversibility of cell death by channel blockade provides an attractive area of investigation in consideration of treatable axonal degeneration.8 page(s