Dark Matter Constraints on Composite Higgs Models

In composite Higgs models the pseudo-Nambu-Goldstone Boson (pNGB) nature of the Higgs field is an interesting alternative for explaning the smallness of the electroweak scale with respect to the beyond the Standard Model scale. In non-minimal models additional pNGB states are present and can be a Dark Matter (DM) candidate, if there is an approximate symmetry suppressing their decay. Here we assume that the low energy effective theory (for scales much below the compositeness scale) corresponds to the Standard Model with a pNGB Higgs doublet and a pNGB DM multiplet. We derive general effective DM Lagrangians for several possible DM representations (under the SM gauge group), including the singlet, doublet and triplet cases. Within this framework we discuss how the DM observables (relic abundance, direct and indirect detection) constrain the dimension-6 operators induced by the strong sector assuming that DM behaves as a Weakly Interacting Particle (WIMP) and that the relic abundance is settled through the freeze-out mechanism. We also apply our general results to two specific cosets: $SO(6)/SO(5)$ and $SO(6)/SO(4) \times SO(2)$, which contain a singlet and doublet DM candidate, respectively. In particular we show that if compositeness is a solution to the little hierarchy problem, representations larger than the triplet are strongly disfavored. Furthermore, we find that composite models can have viable DM candidates with much smaller direct detection cross-sections than their non-composite counterparts, making DM detection much more challenging.Comment: version accepted by JHE

Hydrogen-Bonded Rosettes of Aminotriazines for Selective-Ion Recognition

Ion recognition is still an emerging topic in supramolecular chemistry and has aroused great attention in the last few years. In this work, we have examined the assemblies of selected hexameric rosettes of melamine and ammeline and their capacities to host halide and alkali ions in the gas phase and in water. Using relativistic dispersion-corrected density functional theory (DFT-D), we first studied the stability and the effect of introducing monovalent anions (Cl-, Br-, and I-) and cations (Na+, K+, and Rb+) in the center of the rosette´s cavity. Finally, we explored the interactions in two stacked rosettes with an interlayer ion. Our computations reveal that amine-substituted triazines are promising candidates for anion and cation recognition either in self-assembled monolayers or pillar array structures. The anion recognition process is governed by both the electrostatic and charge-transfer (donor-acceptor) interactions, while the cation recognition is governed by electrostatic and polarization. In addition, melamine and ammeline could constitute a potent mixture for dual-ion recognition strategies.Fil: Petelski, Andre Nicolai. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Vrije Universiteit Amsterdam; Países Bajos. Universidad Tecnológica Nacional. Facultad Regional Resistencia. Departamento de Ingeniería Química. Laboratorio de Química Teórica y Experimental; ArgentinaFil: Fonseca Guerra, Célia. Vrije Universiteit Amsterdam; Países Bajo

A Multi-Layered Architecture for Collaborative and Decentralized Consequence Finding

The consequence finding problem consists in producing all the consequences of a logical theory or, depending on the application context, in a restricted subset of these consequences. When the available knowledge is naturally scattered among different sources of information, computing such consequences with respect to the global theory in a decentralized way is a challenging problem. This paper presents Somewhere2, a multilayered architecture that may be used to solve such consequence finding problems in peer-to-peer networks of collaborating entities, that may evolve over time. The general layout of this architecture is described as well as the roles of its main components. Thanks to a careful and modular design, the resulting framework is very generic. This facilitates alternative implementations of specific components as well as its extension with additional features. First experimental results are presented, illustrating the scalability and robustness of this architecture. This framework may be used as a robust building block for more advanced distributed applications, such as Peer Data Management Systems

O conceito de potência emergente na hierarquia política e econômica internacional

Este trabalho tem por objetivo analisar o conceito de potências emergentes criado para a compreensão dos assuntos internacionais. O trabalho observa que o emprego do léxico emergentes – em relação aos mercados, países ou poderes – como qualificador para uma gama de fenômenos de relações internacionais tornou-se parte integrante da questão. Apesar disso, a denotação empírica do predicado está à frente da quantidade de esforços em sua contextualização teórica. Nossa hipótese metodológica é que a negação racional dos conceitos predominantes do espectro conotativo, reconhecendo a sabedoria incorporada sobre fenômenos cognatos sintetiza um quadro teórico sobre a sua utilização precisa.This paper aims to analyze the concept of emerging power established to the understanding of international affairs. The work observes that the use of the lexicon emerging – regarding to markets, countries or powers – as qualifier for a range of international relations phenomena became a constituent part of the matter. In spite of that, the empirical denotation of the predicate is ahead of the amount of efforts on its theoretical contextualization. Our methodological hypothesis is that the rational denial of the concepts prevailing connotative spectrum by acknowledging the embedded wisdom about cognate phenomena synthesizes a theoretical framework on its accurate use

Investigation of material flow and thermomechanical behavior during friction stir welding of an AZ31B alloy for threaded and unthreaded pin geometries using computational solid mechanics simulation

In the friction stir welding process, the tool role in the material flow and its thermomechanical behavior is still not entirely understood. Several modeling approaches attempted to explain the material and tool relationship, but to this date, insufficient results were provided in this matter. Regarding this issue and the urgent need for trustful friction stir welding models, a computational solid mechanic's model capable of simulating material flow and defect formation is presented. This model uses an Arbitrary Lagrangian-Eulerian code comparing a threaded and unthread pin profile. The model was able to reproduce the tool's torque, temperatures, and material flow along the entire process, including the underreported downward flow effect promoted by threaded pin's. A point tracking analysis revealed that threads increase the material velocity and strain rate to almost 30% compared to unthreaded conditions, promoting a temperature increment during the process, which improved the material flow and avoided filling defects. The presented results showed the model's capability to reproduce the defects observed in real welded joints, material thermomechanical characteristics and high sensitivity to welding parameters and tool geometries. Nevertheless, the outcomes of this work contribute to essential guidelines for future friction stir welding modeling and development, tool design, and defect predictionPeer ReviewedPostprint (author's final draft

Marine nematode taxonomy in the DNA age: the present and future of molecular tools to access their biodiversity

Molecular taxonomy is one of the most promising yet challenging fields of biology. Molecular markers such as nuclear and mitochondrial genes are being used in a variety of studies surveying marine nematode taxa. Sequences from more than 600 species have been deposited to date in online databases. These barcode sequences are assigned to 150 nominal species from 104 genera. There are 41 species assigned to Enoplea and 109 species to Chromadorea. Morphology-based surveys are greatly limited by processing speed, while barcoding approaches for nematodes are hampered by difficulties in matching sequence data with morphology-based taxonomy. DNA barcoding is a promising approach because some genes contain variable regions that are useful to discriminate species boundaries, discover cryptic species, quantify biodiversity and analyse phylogeny. We advocate a combination of several approaches in studies of molecular taxonomy, DNA barcoding and conventional taxonomy as a necessary step to enhance the knowledge of biodiversity of marine nematodes

Plant-hummingbird interactions and temporal nectar availability in a <i>arestinga </i>from Brazil

ABSTRACT Hummingbirds are the most important and specialized group of pollinating birds in the Neotropics and their interactions with plants are key components to many communities. In the present study we identified the assemblage of plants visited by hummingbirds and investigated the temporal availability of floral resources in an area of restinga, sandy plain coastal vegetation associated with the Atlantic forest, in Southeastern Brazil. We recorded flower and nectar features, flowering phenology and interactions between plants and hummingbirds and estimated the amount of calories produced per hectare from June 2005 to August 2006. Ten plant species were visited by two hummingbirds,Amazilia fimbriata and Eupetomena macroura. Resource availability was highly variable among plant species and over time. Nectar volume and concentration per flower were similar to other Neotropical hummingbird-visited plant assemblages. The estimated nectar resource availability between months varied from 0.85 to 5.97 Kcal per hectare/day, demanding an area between one and 6.8 ha to support a single hummingbird. Our study reports an unusual tropical setting where almost all interactions between hummingbirds and plants were performed by a single hummingbird species,A. fimbriata. Hence, the variable nectar availability is probably influencing hummingbird movements, its foraging area, and consequently plant pollination

Risk Analysis Of Groundwater Contamination By Pesticide Residues In Campo Novo Do Parecis (mt), Brazil

Considering the possibility that pesticides used in main crops, such as soybeans, cotton and corn, generate toxic residues that contaminate the environment, a preliminary analysis of the possibility of groundwater contamination is necessary in the main agricultural regions in Brazil. One of these agricultural areas is located in Campo Novo do Parecis, Mato Grosso, the study area of this work. The main pesticides used in different cultures of this region were evaluated considering their physicochemical properties, their contamination potentials according to criteria of the Environmental Protection Agency of the United States and the groundwater ubiquity score index (GUS). The information obtained was used to assess the risk of groundwater contamination. According to the results, the region presents a real risk of environmental contamination by pesticide residues, since 45.6% of the pesticides commonly used in local agriculture are classified as extremely toxic or highly toxic. In addition, several of these pesticides, about 22%, have been detected in different environmental compartments from other regions of the state of Mato Grosso, Brazil.22227728