A new approach on the stability analysis in ELKO cosmology

In this work it has been developed a new approach to study the stability of a system composed by an ELKO field interacting with dark matter, which could give some contribution in order to alleviate the cosmic coincidence problem. It is assumed that the potential which characterizes the ELKO field is not specified, but it is related to a constant parameter $\delta$. The strength of the interaction between matter and ELKO field is characterized by a constant parameter $\beta$ and it is also assumed that both ELKO field as matter energy density are related to their pressures by equations of state parameters $\omega_\phi$ and $\omega_m$, respectively. The system of equations is analysed by a dynamical system approach. It has been found the conditions of stability between the parameters $\delta$ and $\beta$ in order to have stable fixed points for the system for different values of the equation of state parameters $\omega_\phi$ and $\omega_m$, and the results are presented in form of tables. The possibility of decay of ELKO field into dark matter or vice versa can be read directly from the tables, since the parameters $\delta$ and $\beta$ satisfy some inequalities. It allows us to constrain the potential assuming that we have a stable system for different interactions terms between the ELKO field and dark matter. The cosmic coincidence problem can be alleviated for some specific relations between the parameters of the model.Comment: 16 pages, some new comments in the Introduction and at the begining of Section I

Some remarks on the attractor behaviour in ELKO cosmology

Recent results on the dynamical stability of a system involving the interaction of the ELKO spinor field with standard matter in the universe have been reanalysed, and the conclusion is that such system does not exhibit isolated stable points that could alleviate the cosmic coincidence problem. When a constant parameter $\delta$ related to the potential of the ELKO field is introduced in the system however, stable fixed points are found for some specific types of interaction between the ELKO field and matter. Although the parameter $\delta$ is related to an unknown potential, in order to satisfy the stability conditions and also that the fixed points are real, the range of the constant parameter $\delta$ can be constrained for the present time and the coincidence problem can be alleviated for some specific interactions. Such restriction on the ELKO potential opens possibility to apply the ELKO field as a candidate to dark energy in the universe, and so explain the present phase of acceleration of the universe through the decay of the ELKO field into matter.Comment: 17 pages, section III with minor changes and section IV rewritten with a new analysi

Clonagem in vitro via cultivo de meristema de pimenteira-do-reino: assepsia e estabelecimento de cultura.

A cultura da pimenteira-do-reino tem grande importância econômica no Brasil, mas há restrição de cultivo devido a vulnerabilidade genética da mesma à doença fusariose causada pelo fungo Fusarium solani f. sp.piperis. A forma de propagação vegetativa é disseminadora da doença e métodos de controle da doença são pouco exitosos. Programas de melhoramento em execução visam gerar híbridos resistentes à doença em questão, além de agregar características agronômicas competitivas. Doenças viróticas ocorrem em todas as cultivares e há necessidades de limpeza clonal dessas cultivares via cultura de tecidos. Há dificuldades de obtenção de explantes assépticos devido a problemas de bactérias e fungos endógenos. Este trabalho teve por objetivo o estabelecimento de meristema (<1,0 mm) in vitro para a limpeza clonal via micropropagação. A partir de plantas originadas de estacas, meristemas (apicais e laterais) foram excisados a partir segmentos nodais e apicais, previamente submetidos a diferentes tratamentos de assepsia. Os meristemas foram inoculados em meio básico de cultura MS suplementado com BAP 0,5 mg.L-1 e AIA 0,2 mg.L-1. As respostas dos meristemas das diferentes cultivares foram avaliadas quanto a oxidação e contaminação, e os explantes verdes foram transferidos para meios frescos visando a diferenciação de brotos. Dos meristemas de nove cultivares utilizadas, apenas alguns das cultivares IAÇARÁ e genótipo 239 apresentaram desenvolvimento satisfatório. As demais não desenvolveram, oxidaram e/ ou sofreram contaminação por fungos e/ ou bactérias

Eficiência da fosfina no controle da broca da raiz do cajueiro, Marshallius bondari Rosado Neto, 1989 (Col., Curculionidae).

Eficiencia da fosfina no controle da broca da raiz do cajueiro.bitstream/CNPAT-2010/1840/1/Pa-015.pd

Controle químico da broca do tronco do cajueiro, Marshallius anacardii Lima, 1979 (Col., Curculionidae)

Controle quimico da broca do tronco do cajueiro.bitstream/CNPAT-2010/1851/1/Pa-013.pd

Predictors and Moderators of Quality of Life Among College Students With ADHD

Objective: The current study examines (a) whether ADHD among college students is associated with differences in perceptions of quality of life (QoL); (b) the moderating roles of comorbidity, drug use, psychopharmacological treatment, and psychosocial treatment; and (c) the total impact of these variables on QoL. Method: Participants were college students with and without ADHD (N = 372) in a longitudinal study. Results: College students with ADHD were more likely to assert negative global QoL evaluations relative to non-ADHD peers. The relationship between ADHD and QoL was not altered as a function of medication treatment, comorbid psychopathology, psychosocial treatment, or drug use. Conclusion: College students with ADHD behave similarly to other adults with ADHD in that they make lower subjective global evaluations of their QoL relative to their non-ADHD agemates. Other factors associated with ADHD and QoL do not appear to moderate this relationship

Seismic hazard and risk due to induced earthquakes at a shale gas site

Hydraulic fracturing of the first shale gas well at Preston New Road (PNR), Blackpool, United Kingdom, in late 2018, marked the end of a 7 yr United Kingdom‐wide moratorium on fracking. Despite a strict traffic‐light system being in place, seismic events up to ML 2.9 were induced. The ML 2.9 event was accompanied by reports of damage and was assigned European Macroseismic Scale 1998 (EMS‐98) intensity VI by the British Geological Survey. The moratorium was subsequently reinstated in late 2019. The study here presents a pseudo‐probabilistic seismic risk analysis and is applied to the larger of the induced events at PNR, in addition to hypothetical larger events. Initially, site characterization analysis is undertaken using direct and indirect methods. These analyses show low‐velocity deposits dominate the region (⁠VS30¯¯¯¯¯¯=227  m/s⁠). We test existing ground‐motion prediction equations using spatially dependent VS30 to determine applicability to the recorded waveform data and produce a referenced empirical model. Predicting median and 84th percentile peak ground velocity fields, we subsequently determine macroseismic intensities. Epicentral intensities of IV, IV–V, and VI–VII are predicted for the observed ML 2.9, and hypothetical ML 3.5 and 4.5 scenarios, respectively. A probabilistic analysis of damage is performed for 3500 ground‐motion realizations (⁠2.1≤ML≤4.5⁠) using the OpenQuake‐engine, with nonlinear dynamic analysis undertaken to define building fragility. Based on these analyses, the onset of cosmetic damage (DS1) in terms of median risk is observed for the ML 2.9 event. Mean modeled occurrences of DS1 and DS2 (minor structural damage), 75 and 10 instances, respectively, are consistent with reported damage (DS1:97, DS2:50). Significant occurrences (⁠median≥30 buildings) of DS2, DS3, and DS4 (minor to major structural damage) are likely for ML 3.5, 4.0, and 4.5 events, respectively. However, by comparing reported damage with modeled damage due to the ML 2.9 event and considering the fact that low macroseismic intensities (EMS‐98 <4⁠) are often not reported by the public, we conclude that the previously assigned intensity of VI is too high, with V being more appropriate

Flexible and dynamic replication control for interdependent distributed real-time embedded systems

Replication is a proven concept for increasing the availability of distributed systems. However, actively replicating every software component in distributed embedded systems may not be a feasible approach. Not only the available resources are often limited, but also the imposed overhead could significantly degrade the system’s performance. This paper proposes heuristics to dynamically determine which components to replicate based on their significance to the system as a whole, its consequent number of passive replicas, and where to place those replicas in the network. The activation of passive replicas is coordinated through a fast convergence protocol that reduces the complexity of the needed interactions among nodes until a new collective global service solution is determined