2,280 research outputs found
Study of chaos in hamiltonian systems via convergent normal forms
We use Moser's normal forms to study chaotic motion in two-degree hamiltonian
systems near a saddle point. Besides being convergent, they provide a suitable
description of the cylindrical topology of the chaotic flow in that vicinity.
Both aspects combined allowed a precise computation of the homoclinic
interaction of stable and unstable manifolds in the full phase space, rather
than just the Poincar\'e section. The formalism was applied to the
H\'enon-Heiles hamiltonian, producing strong evidence that the region of
convergence of these normal forms extends over that originally established by
Moser.Comment: 29 pages, REVTEX, 22 postscript figures on reques
Somatic embryogenesis and in vitro plant regeneration from pejibaye adult plant leaf primordia
Civil Registry of minor transgender in Brazil and Spain
This article aims to reflect on the adequacy of the name and gender in the Civil Registry of the minor transgender in Brazilian law and Spanish law, since the problem seems to be appeased only with regard to the transgender person of legal age and capable. Spain is slightly ahead of Brazil in this matter, as it already has a constitutional decision in favor of the smallest transgender, however, both countries still do not present rules applicable to these individuals, nor does it have pacification in the judiciary on the subject. Thus, through qualitative methodology, with an emphasis on bibliographic and normative research, elements are presented to bridge the legislative gap in relation to the smallest transgender, in both countries, aiming to alleviate the arduous and slow march of these individuals to ensure the adequacy of the first name and gender, justifying the present study. In this perspective, preventing the desired adequacy may constitute a restriction of their fundamental rights, in addition to preventing the free development of the minor's personality according to their gender
A hypothesis for the anti-inflammatory and mechanotransduction molecular mechanisms underlying acupuncture tendon healing
A previous study demonstrated that acupuncture increases the synthesis and reorganisation of collagen molecules in rat tendons after injury. Clinical studies have shown that acupuncture improves pain and functional activity in patients with tendinopathy. However, the molecular mechanisms underlying these effects are unknown. Recent studies have shown that acupuncture can modulate both anti-inflammatory (AI) and mechanotransduction (MT) molecular pathways. Moreover, the modulation of these pathways can increase type I collagen synthesis, which is the main factor that influences tendon biomechanical properties. Our hypothesis is that acupuncture increases synthesis and subsequent reorganisation of type I collagen during tendon healing by concomitant modulation of the Toll-like receptor-nuclear factor-kappa B AI pathway, the mitogen-activated protein kinases pathway and the Rho/Rac-F-actin MT pathway. Increased collagen synthesis and reorganisation requires that at least one acupoint is anatomically connected with the site of the injury because of the local tenoblast MT mechanism. Confirmation of this hypothesis will increase the knowledge of acupuncture modulation of the previously mentioned molecular pathways, and such confirmation may also help to establish the relationships between the different types of acupuncture needle stimulation and the influence of acupuncture stimuli on pathway activity levels. In addition, the downstream therapeutic effects of acupuncture therapy may be established. This hypothesis can be verified in a rat tendon healing model, and subsequent clinical protocols for tendon healing can be developed and evaluated as standalone therapies or as a component of a combination therapy32217818
Utilização de Pseudomanas fluorescens no controle biológico de Macrophomina phaseolina.
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Effect of the acid environment on the electrochemical behaviour of 1045 steel reinforced cement
External corrosion is one of the most common causes of oilwell casing failure. Hostile
environments can be due to acidizing treatments. Although it is common to add corrosion inhibitors
and oxygen scavengers in acidic solutions to control external casing corrosion, their real efficiency
is unknown yet. Therefore, it is important to establish how aggressive to steel are the different
hostile environments to help decide which acidic systems can be used. A comparative evaluation of
the corrosion of steel immersed in hardened cement slurries submitted to commonly acidizing
agents is suggested. The performance of Special Class Portland Cement Slurries reinforced with
polished SAE 1045 steel was evaluated by electrochemical measurements as a function of time.
Open circuit potential, polarization curves and electrochemical impedance spectroscopy were
studied. 15.0 wt% HCl, 12.0 wt% HCl + 3.0 wt% HF (regular mud acid), 10.0 wt% HAc + 1.5 wt%
HF and a simulated hardened cement slurry pore solution were used as electrolytes. The most
aggressive acid solution to plain Portland hardened cement slurries was the regular mud acid. 10.0
wt% HAc + 1.5 wt% HF electrolytes were the least aggressive ones, showing open circuit
potentials around +250 mV compared to -130 mV of the simulated hardened cement slurry pore
solution after the first 24 hours of immersion. This behavior was observed during two months at
least. Similar corrosion rates were shown between both electrolytes, around 0.01 μA.cm-2. Total
impedance values, insipient arcs and large polarization resistance capacitive arcs on the Nyquist
plots, indicating passivity process, confirmed the behaviour of the system in the 10.0 wt% HAc +
1.5 wt% HF electrolyte.The authors acknowledge FACEPE and PRH30/ANP/MCTPETROBRAS for the financial support
ENERGY COST DURING WALKING AND RUNNING A SAME DISTANCE IS ASSOCIATED WITH VERTICAL OSCILLATION ON GRAVITY CENTER.
The purpose of this study was to evaluate which factors are involved in energetic cost of running and walking a same distance (2,000 meters). Eight healthy men were submitted
to walking (5.5km/h) and running (11Km/h) tests, when oxygen consumption, for energy expenditure of exercise, was monitored, and images of volunteers were recorded for
vertical oscillation of gravity center. Both, total oxygen consumption and estimated energetic cost were significantly higher during the running test (
Diversity, distribution and new records of freshwater and estuarine shrimp in the state of Amapá, eastern Brazilian Amazon region.
This study presents the freshwater and estuarine shrimp species that occur in the state of Amapá, in the eastern region of the Brazilian Amazon. The data were obtained through information contained in the Brazilian crustacean collections of the Institute of Scientific and Technological Research of the State of Amapá (IEPA) and the National Institute for Research in the Amazon (INPA) and the detailed examination of the listed specimens. All information contained in the log book and specimen labels were noted for the identification and mapping of occurrence areas in the region. A survey in the literature of the species previously recorded for Amapá was carried out. The diversity of freshwater and estuarine shrimp was composed of 21 species distributed in the following families: Alpheidae (Alpheus nuttingi), Euryrhynchidae (Euryrhynchus amazoniensis, Euryrhynchus burchelli, Euryrhynchus tomasi and Euryrhynchus wrzesniowskii), Lysmatidae (Exhippolysmata oplophoroides), Palaemonidae (Macrobrachium acanthurus, Macrobrachium amazonicum, Macrobrachium brasiliense, Macrobrachium carcinus, Macrobrachium jelskii, Macrobrachium inpa, Macrobrachium olfersii, Macrobrachium surinamicum, Nematopalemon schmitti, Palaemon carteri, Pseudopalaemon amazoniensis, Pseudopalaemon chryseus, Leander tenuicornis), Penaeidae (Xiphopenaeus kroyeri and Sergestidae) (Acetes marinus and Acetes paraguayensis). Alpheus nuttingi and L. tenuicornis were new records for the state of Amapá. This study contributes to the knowledge of the diversity and geographic distribution of decapod crustaceans in Amapá and highlights areas where there are gaps in collection, thus contributing to a better understanding of these invertebrates in the region
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