4,353 research outputs found
The CP-conserving 2HDM after the 8 TeV run
We confront the most common CP-conserving 2HDM with the LHC data analysed so
far while taking into account all previously available experimental data. A
special allowed corner of the parameter space is analysed - the so-called
wrong-sign scenario where the Higgs coupling to down-type quarks changes sign
relative to the Standard Model while the coupling to the massive vector bosons
does not.Comment: 6 pages, 2 figures, to appear in the proceedings of the 22nd
International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS
2014), 28 April - 2 May 2014 Warsaw (Poland
The Wrong Sign limit in the 2HDM
A sign change in the Higgs couplings to fermions and massive gauge bosons is
still allowed in the framework of two-Higgs doublet models (2HDM). In this work
we discuss the possible sign changes in the Higgs couplings to fermions and
gauge bosons, while reviewing the status of the 8-parameter CP-conserving 2HDM
after the Large Hadron Collider 8 TeV run.Comment: 6 pages, 3 figures. Proceedings of the Second Annual Conference on
Large Hadron Collider Physics, Columbia University, New York, U.S.A, June
2-7, 2014. arXiv admin note: text overlap with arXiv:1407.439
Electrokinetic treatment of environmental matrices. Contaminants removal and phosphorus recovery
There is a need to develop viable techniques for removal and recovery organic and inorganic compounds from environmental matrices, due to their ecotoxicity, regulatory obligations or potential supplies as secondary materials.
In this dissertation, electro –removal and –recovery techniques were applied to five different contaminated environmental matrices aiming phosphorus (P) recovery and/or contaminants removal. In a first phase, the electrokinetic process (EK) was carried out in soils for (i) metalloids and (ii) organic contaminants (OCs) removal. In the case of As and Sb mine contaminated soil, the EK process was additionally coupled with phytotechnologies. In a second phase, the electrodialytic process (ED) was applied to wastes aiming P recovery and simultaneous removal of (iii) toxins from membrane
concentrate, (iv) heavy metals from sewage sludge ash (SSA), and (v) OCs from sewage sludge (SS).
EK enhanced phytoremediation showed to be viable for the remediation of soils contaminated with metalloids, as although remediation was low, it combines advantages of both technologies while allowing site management. EK also proved to be an effective remediation technology for the removal and degradation of emerging OCs from two types of soil.
Aiming P recovery and contaminants removal, different ED cell set-ups were tested. For the membrane concentrates, the best P recovery was achieved in a three compartment (3c) cell, but the highest toxin removal was obtained in a two compartment (2c) cell, placing the matrix in the cathode end. In the case of SSA the best approach for simultaneous P recovery and heavy metals removal was to use a 2c-cell placing the matrix in the anode end. However, for simultaneous P recovery and OCs removal, SS should be placed in the cathode end, in a 2c-cell.
Overall, the data support that the selection of the cell design should be done case-by-case
Regeneração natural de castanheira da Amazônia e interação de seu crescimento inicial com atributos do solo e luz.
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Contest behaviour of maize weevil larvae when competing within seeds
Food limitation induces severe competition for obligate seed-feeding insect larvae that are unable to leave the seed selected by their mother. The number of eggs laid per seed and the number of larvae hatched from the eggs are important determinants of whether larval behaviour within the seed will be of the scramble or the contest type. In maize weevils, Sitophilus zeamais, few adults emerge per seed regardless of the number of eggs laid, which may arise from scramble competition, if the optimum egg density (i.e. egg density leading to maximum total larval fitness) is low compared to the number of eggs laid per seed, or from contest competition due to direct interference among the larvae. The behavioural process and the ecological outcome of competition were assessed in two strains of the maize weevil. Neither strain showed a reduction in body mass with increased competition, and they had similar optimal egg densities (two eggs per seed). There was a hump in the larval fitness curve suggesting a scramble competition, but this conclusion is compromised because the optimum egg density was small (two eggs per seed). X-ray imaging of seeds was used to observe interactions of larvae within the seed and showed direct interference, with aggression among the larvae. This provides evidence of contest-like competition within seeds even when egg density was low. Hence, one should be cautious in inferring the underlying type of competitive behaviour from variables such as body mass and initial egg density per seed. Direct observation of behaviour is required to make such an inference
Contest behaviour of maize weevil larvae when competing within seeds
Food limitation induces severe competition for obligate seed-feeding insect larvae that are unable to leave the seed selected by their mother. The number of eggs laid per seed and the number of larvae hatched from the eggs are important determinants of whether larval behaviour within the seed will be of the scramble or the contest type. In maize weevils, Sitophilus zeamais, few adults emerge per seed regardless of the number of eggs laid, which may arise from scramble competition, if the optimum egg density (i.e. egg density leading to maximum total larval fitness) is low compared to the number of eggs laid per seed, or from contest competition due to direct interference among the larvae. The behavioural process and the ecological outcome of competition were assessed in two strains of the maize weevil. Neither strain showed a reduction in body mass with increased competition, and they had similar optimal egg densities (two eggs per seed). There was a hump in the larval fitness curve suggesting a scramble competition, but this conclusion is compromised because the optimum egg density was small (two eggs per seed). X-ray imaging of seeds was used to observe interactions of larvae within the seed and showed direct interference, with aggression among the larvae. This provides evidence of contest-like competition within seeds even when egg density was low. Hence, one should be cautious in inferring the underlying type of competitive behaviour from variables such as body mass and initial egg density per seed. Direct observation of behaviour is required to make such an inference
Mating behaviour and reproductive output in insecticide-resistant and -susceptible strains of the maize weevil (\u3ci\u3eSitophilus zeamais\u3c/i\u3e)
Insecticide resistance is a broadly recognised and well-studied management problem resulting from intensive insecticide use, which also provides useful evolutionary models of newly adapted phenotypes to changing environments. Two common assumptions in such models are the existence of fitness costs associated with insecticide resistance, which will place the resistant individuals at a disadvantage in insecticide-free environments, and the prevalence of random mating among insecticide-resistant and -susceptible individuals. However, cases of insecticide resistance lacking apparent fitness disadvantages do exist impacting the evolution and management of insecticide resistance. Assortative mating, although rarely considered, may also favour the evolution and spread of insecticide resistance. Thus, the possible existence of both conditions in the maize weevil (Sitophilus zeamais), a key pest of stored cereals, led to the assessment of the mating behaviour and reproductive fitness of insecticide-resistant and -susceptible weevil strains and their reciprocal crosses. The patterns of female and male mating choice also were assessed. Although mating behaviour within and between weevil strains was similar without mate choice, mating within the resistant strain led to higher reproductive output than within the susceptible strain; inter-strain matings led to even higher fertility. Thus, no apparent fitness cost associated with resistance seems to exist in these weevils, favouring the evolution of this phenotype that is further aided by the higher fertility of inter-strain matings. Mate choice reduced latency to mate and no inter-strain preference was detected, but female weevils were consistent in their mate selection between 1st and 2nd matings indicating existence of female mating preference among maize weevils. Therefore, if female mate selection comes to favour trait(s) associated with insecticide resistance, higher reproductive fitness will be the outcome of such matings favouring the evolution and spread of insecticide resistance among maize weevil populations reverting into a management concern
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