Invariant tori and boundedness of solutions of non-smooth oscillators with Lebesgue integrable forcing term

Since Littlewood works in the 1960's, the boundedness of solutions of Duffing-type equations $\ddot{x}+g(x)=p(t)$ has been extensively investigated. More recently, some researches have focused on the family of non-smooth forced oscillators $\ddot{x}+\text{sgn}(x)=p(t)$, mainly because it represents a simple limit scenario of Duffing-type equations for when $g$ is bounded. Here, we provide a simple proof for the boundedness of solutions of the non-smooth forced oscillator in the case that the forcing term $p(t)$ is a $T$-periodic Lebesgue integrable function with vanishing average. We reach this result by constructing a sequence of invariant tori whose union of their interiors covers all the $(t,x,\dot x)$-space, $(t,x,\dot{x})\in \mathbb{S}^1\times\mathbb{R}^2$

Gravitational Laser Back-Scattering

A possible way of producing gravitons in the laboratory is investigated. We evaluate the cross section electron + photon $\rightarrow$ electron + graviton in the framework of linearized gravitation, and analyse this reaction considering the photon coming either from a laser beam or from a Compton back-scattering process.Comment: 11 pages, 2 figures (available upon request), RevTeX, IFT-P.03/9

Efeitos de micronutrientes em capim colonião (Panicum maximum, Jacq.) cultivado num solo de campo cerrado.

Utilizando-se de um solo de campo cerrado (Latosol Vermelho Amarelo - fase arenosa), que nunca recebeu qualquer adubação, instalou-se este experimento em vasos, em casa de vegetação, com a finalidade de se verificar a influencia dos micronutrientes: Manganês, molibdenio, cobre, zinco e boro, sobre o desenvolvimento do capim colonia

Identifying the Higgs Boson in Electron--Photon Collisions

We analyze the production and detection of the Higgs boson in the next generation of linear $e^+e^-$ colliders operating in the $e\gamma$ mode. In particular, we study the production mechanism $e + \gamma \rightarrow e \gamma \gamma \rightarrow e + H$, where one photon is generated via the laser backscattering mechanism, while the other is radiated via the usual bremsstrahlung process. We show that this is the most important mechanism for Higgs boson production in a $500$ GeV $e\gamma$ collider for M_H\raisebox{-.4ex}{\rlap{\sim}} \raisebox{.4ex}{>}140 GeV. We also study the signals and backgrounds for detection of the Higgs in the different decay channels, $b \bar b$, $W^+W^-$, and $ZZ$, and suggest kinematical cuts to improve the signature of an intermediate mass Higgs boson.Comment: (REVTEX 2.0, 12 pages and 9 figures available upon request, Preprint MAD/PH/753

Estefanofilariose: uma zoonose.

bitstream/item/26294/1/DOC21-2006.pd

Quartic Anomalous Couplings in γγ\gamma\gamma Colliders

We study the constraints on the vertices $W^+W^- Z\gamma$, $W^+W^-\gamma\gamma$, and $ZZ\gamma\gamma$ that can be obtained from triple-gauge-boson production at the next generation of linear $e^+e^-$ colliders operating in the $\gamma\gamma$ mode. We analyze the processes $\gamma\gamma \to W^+W^-V$ ($V=Z$, or $\gamma$) and show that these reactions increase the potential of $e^+e^-$ machines to search for anomalous four-gauge-boson interactions.Comment: 15 pages, Latex file using ReVteX, 4 uufiled figures include

Stressors in the ICU: different perceptions of patients, relatives and staff members

Introduction The high-risk critically ill are exposed to signifi cant stressors, along with diffi culties in communicating them to relatives and members of the staff . The aim of this study was to compare the perception of stressors as reported by patients (P), relatives (R) and ICU staff members (S). Methods A validated questionnaire [1] was used to quantitatively assess discomforts related to the ICU stay. Items were clustered into categories; higher scores refer to a higher stressfulness. The median (IQR) was calculated for each category. Twenty-eight high-risk critically ill at discharge, 55 relatives 48 hours after admission of their next of kin, and a total of 125 staff members (55 attending physicians, 40 nurses and 30 medical students/specialist trainees) were interviewed. Fifty-six of the staff members were used to keep patients consciously sedated as for local guidelines; the remaining used deeper levels of sedation. Nonparametric tests were used as needed. Results All stressor categories were diff erently reported by the three groups analysed: environmental (S = 17 (15 to 19), R = 15 (13 to 18), P = 10 (8 to 11), P <0.01), relationships (S = 23 (21 to 25), R = 20.5 (17 to 24.5), P = 14 (11 to 17), P <0.01), emotional (S = 25.5 (23 to 28), R = 24 (20 to 26), P = 18 (15 to 22), P <0.01), and physical (S = 35 (31 to 38), R = 33 (26.5 to 37), P = 27 (21 to 30), P <0.01). Among the staff members, nurses overestimated more than attending physicians, while trainees are closer to relatives\u2019 perception (P = 0.03). Staff members used to conscious sedation overestimate less the impact of environmental stressors (P = 0.03). Years of experience (r = 0.24, P = 0.03) and age (r = 0.27, P = 0.01) are related to stressor overestimation among staff members. Conclusion Members of the staff should reconsider their beliefs on patients\u2019 perception of stressors. We argue that such an overestimation may bring inappropriate administration of analgesic and sedative drugs, particularly for nurses and older members of staff . Relatives might be useful intermediaries to have a better insight of patients\u2019 perception

Discriminating New Physics Scenarios at NLC: The Role of Polarization

We explore the potential of the Next Linear Collider (NLC), operating in the $e\gamma$ mode, to disentangle new physics scenarios on single $W$ production. We study the effects related with the exchange of composite fermion in the reaction $e\gamma \to W \nu_e$, and compare with those arising from trilinear gauge boson anomalous couplings. We stress the role played by the initial state polarization to increase the reach of this machine and to discriminate the possible origin of the new phenomena.Comment: 26 pages, LaTeX file using ReVTeX. 10 Figure