Asymptotic stability at infinity for differentiable vector fields of the plane

Let X:R2\Dr->R2 be a differentiable (but not necessarily C1) vector field, where r>0 and Dr={z\in R2:|z|\le r}. If for some e>0 and for all p\in R2\Dr, no eigenvalue of D_p X belongs to (-e,0]\cup {z\in\C:\mathcal{R}(z)\ge 0}, then (a)For all p\in R2\Dr, there is a unique positive semi--trajectory of X starting at p; (b)\mathcal{I}(X), the index of X at infinity, is a well defined number of the extended real line [-\infty,\infty); (c) There exists a constant vector v\in R2 such that if \mathcal{I}(X) is less than zero (resp. greater or equal to zero), then the point at infinity \infty of the Riemann sphere R2\cup\set{\infty} is a repellor (resp. an attractor) of the vector field X+v.Comment: 16 pages, 7 figure

Quimerismo 60,xx/60,xy e freemartismo em bovinos nascidos de partos gemelares heterossexuais.

Foram estudados citogeneticamente 42 bovinos nascidos de partos gemelares heterossexuais, sendo 10 casais, 19 fêmeas e três machos de várias raças, principalmente, Holandesa (17) e Pardo Suíça (11), pertencentes ao Instituto de Zootecnia-APTA, Nova Odessa, SP, e a produtores particulares de outras regiões do Estado. A análise citogenética foi realizada em metáfases obtidas após culturas de linfócitos. Em 90,5% (38) dos animais, foi observado o quimerismo 60,XX/ 60,XY com 1,8 a 90,2% de células femininas. Considerando todos os animais quiméricos, foram analisadas 3806 células, sendo 1268 XX (33,3%) e 2538 XY (66,7%). Em nove casais, as freqüências de células femininas foram 24,8 e 21,5% e as de masculinas de 75,2 e 78,5% para fêmeas e machos, respectivamente. Em um casal, não foi evidenciada troca de células, e a fêmea apresentou somente células de linhagem feminina e o macho, de linhagem masculina. Três das fêmeas avaliadas eram adultas e foram abatidas. Seus aparelhos genitais apresentaram vários graus de masculinização como: aumento do clitóris, subdesenvolvimento da vagina, da cérvix (ausente em uma fêmea), do útero, das tubas uterinas, presença de glândulas vesiculares e gônadas ovotestis, (testículos e pênis rudimentares foram encontrados em uma fêmea). O cariótipo 60,XX foi observado em apenas três fêmeas das 29 analisadas: duas delas apresentaram todas as características de fêmea normal e inclusive pariram com aproximadamente 30 meses de idade; a outra fêmea ainda não atingiu a idade de reprodução, mas parece apresentar função reprodutiva normal. Dos 13 machos analisados, 12 apresentaram quimerismo 60,XX/60,XY e um apresentou cariótipo normal (60,XY). A análise citogenética é um meio eficaz e pouco oneroso de constatar freemartismo em fêmea bovina gêmea com macho, permitindo o diagnóstico precoce e a oportunidade de eliminação do processo reprodutivo os animais portadores de quimerismo, de maneira a baixar os custo com manejo e a diminuir a freqüência desta anomalia nos rebanhos

Evading the Few TeV Perturbative Limit in 3-3-1 Models

Some versions of the electroweak SU(3)_L\otimesU(1)_X models cannot be treated within perturbation theory at energies of few TeV. An extended version for these models is proposed which is perturbative even at TeV scale posing no threatening inconsistency for test at future colliders. The extension presented here needs the addition of three octets of vector leptons, which leave three new leptonic isotriplets in the SU(2)_L\otimesU(1)_Y subgroup. With this representation content the running of the electroweak mixing angle, $\theta_W (\mu)$, is such that $\sin^2\theta_W(\mu)$ decreases with the increase of the energy scale $\mu$, when only the light states of the Standard Model group are considered. The neutral exotic gauge boson $Z^\prime$ marks then a new symmetry frontier.Comment: 15 pages, 2 figures, minor correction

Five-Dimensional QED, Muon Pair Production and Correction to the Coulomb Potential

We consider QED in five dimensions in a configuration where matter is localized on a 3-brane while foton propagates in the bulk. The idea is to investigate the effects of the Kaluza-Klein modes of the photon in the relativistic regime, but in low energy, and in the nonrelativistic regime. In the relativistic regime, we calculate the cross section for the reaction $e^+ + e^- \to \mu^+ + \mu^-$. We compare our theoretical result with a precise measurement of this cross section at $\sqrt{s}=57.77$ GeV. As result, we extract a lower bound on the size of the extra dimension. In the nonrelativistic regime, we derive the contribution for the Coulomb potential due to the whole tower of the Kaluza-Klein excited modes of the photon. We use the modified potential to calculate the Rutherford scattering differential cross section.Comment: minor changes, three new refs. added, to appear in IJMP

A Group Intervention or Smoking Cessation: The Impact of a Group Cohesion Strategy on Attendance and Outcome

This study investigated the effectiveness of incorporating methods to boost group processes as means of enhancing attendance and abstinence from smoking for 4 consecutive weeks following a set quit day (self-report and CO monitored on expired breath). A total of 140 smokers (age: M = 48, SD = 12.45; 47% male, 53% female) attended the North West London Specialist clinic. Abstinence was verified by CO levels in expired breath and self-reports. Participants were allocated to two conditions; half attended the traditional Hajek group intervention (HGI) and the remaining received (HGI) plus a “breaking the ice exercise” (BIE). HGI Findings indicated the groups with emphasis on social support and where initial rapport was built were significantly more successful. This study suggests that group methods, rapport and social support play a role in group dynamics affecting therapeutic outcome. Incorporating a simple intervention where patients address each other’s motives for joining the Clinic and introduce their peers augments cohesiveness

Type II Seesaw and a Gauge Model for the Bimaximal Mixing Explanation of Neutrino Puzzles

We present a gauge model for the bimaximal mixing pattern among the neutrinos that explains both the atmospheric and solar neutrino data via large angle vacuum oscillation among the three known neutrinos. The model does not include righthanded neutrinos but additional Higgs triplets which acquire naturally small vev's due to the type II seesaw mechanism. A combination of global $L_e-L_{\mu}-L_{\tau}$ and $S_3$ symmetries constrain the mass matrix for both charged leptons and neutrinos in such a way that the bimaximal pattern emerges naturally at the tree level and needed splittings among neutrinos at the one loop level. This model predicts observable branching ratios for $\tau\to \mu \mu\mu$, which could be used to test it.Comment: Latex file, 8 pages, five figures include

Cosmology of Brane-Bulk Models in Five Dimensions

We study the cosmology of models with four space and one time dimension where our universe is a 3-brane and report a few results which extend existing work in several directions. Assuming a stable fifth dimension, we obtain a solution for the metric, which does not depend on any arbitrary parameters. We discuss some implications of this result.Comment: Minor changes: brane energy conservation law and some typos corrected. All main results unchanged. 11 pages, no figures, LaTeX fil

Labour market policy thematic review 2018: an in-depth analysis of the emigration of skilled labour, Portugal

Following a downturn after 25 April 1974, Portuguese emigration grew steadily once the country joined the EU in 1986 and has accelerated since 2000. The economic trends of stagnation and downward pressure on public investment that followed Portugal’s accession to the Euro generated increased emigration during the first two decades of the 21st Century, mainly due to worsening labour market conditions (Pires et al. 2015; Peixoto et al. 2016). This increase was interrupted by the financial crisis of 2008-10 but reinforced during the fiscal consolidation of 2011-14.info:eu-repo/semantics/publishedVersio