1,303 research outputs found
Snakebites By Bothrops Spp In Children In Campinas, São Paulo, Brazil.
From January, 1984 to March, 1999, 73 children under 15 y old (ages 1-14 y, median 9 y) were admitted after being bitten by snakes of the genus Bothrops. Twenty-six percent of the children were classified as mild envenoming, 50.7% as moderate envenoming and 20.6% as severe envenoming. Two patients (2.7%) showed no signs of envenoming. Most of the patients presented local manifestations, mainly edema (94.5%), pain (94.5%) ecchymosis (73.9%) and blisters (11%). Local and/or systemic bleeding was observed in 28.8% of the patients. Before antivenom (AV) administration, blood coagulation disorders were observed in 60.7% (incoagulable blood in 39.3%) of the 56 children that received AV only in our hospital. AV early reactions, most of which were considered mild, were observed in 44.6% of these cases (in 15/30 patients not pretreated and in 10/26 patients pretreated with hydrocortisone and histamine H1 and H2 antagonists). The main clinical complications observed were local infection (15.1%), compartment syndrome (4.1%), gangrene (1.4%) and acute renal failure (1.4%). No deaths were recorded. There were no significant differences with regard to severity of envenoming versus the frequency of blood coagulation disorders among the three categories of envenoming (p = 0.75) or in the frequency of patients with AV early reactions between the groups that were and were not pretreated (p = 0.55). The frequency of local infection was significantly greater in severe cases (p < 0.001). Patients admitted more than 6 h after the bite had a higher risk of developing severe envenoming (p = 0.04).43329-3
Constraints on narrow exotic states from K+p and K0_Lp scattering data
We consider the effect of exotic S=+1 resonances Theta+ and Theta++ on K+p
elastic scattering data (total cross section) and the process K0_Lp-->K0_Sp.
Data near the observed Theta+(1540) are examined for evidence of additional
states. The width limit for a Theta++ state is reconsidered and shown to be
much less than 1 MeV.Comment: 4 pages, 3 eps figures; minor corrections, one fig adde
Surface-reconstructed Icosahedral Structures for Lead Clusters
We describe a new family of icosahedral structures for lead clusters. In
general, structures in this family contain a Mackay icosahedral core with a
reconstructed two-shell outer-layer. This family includes the anti-Mackay
icosahedra, which have have a Mackay icosahedral core but with most of the
surface atoms in hexagonal close-packed positions. Using a many-body glue
potential for lead, we identify two icosahedral structures in this family which
have the lowest energies of any known structure in the size range from 900 to
15000 lead atoms. We show that these structures are stabilized by a feature of
the many-body glue part of the interatomic potential.Comment: 9 pages, 8 figure
Neurotoxicity of Micrurus lemniscatus lemniscatus (South American coralsnake) venom in vertebrate neuromuscular preparations in vitro and neutralization by antivenom
We investigated the effect of South American coralsnake (Micrurus lemniscatus lemniscatus) venom on neurotransmission in vertebrate nerve-muscle preparations in vitro. The venom (0.1-30 µg/ml) showed calcium-dependent PLA2 activity and caused irreversible neuromuscular blockade in chick biventer cervicis (BC) and mouse phrenic nerve-diaphragm (PND) preparations. In BC preparations, contractures to exogenous acetylcholine and carbachol (CCh), but not KCl, were abolished by venom concentrations ≥ 0.3 µg/ml; in PND preparations, the amplitude of the tetanic response was progressively attenuated, but with little tetanic fade. In low Ca2+ physiological solution, venom (10 µg/ml) caused neuromuscular blockade in PND preparations within ~ 10 min that was reversible by washing; the addition of Ca2+ immediately after the blockade temporarily restored the twitch responses, but did not prevent the progression to irreversible blockade. Venom (10 µg/ml) did not depolarize diaphragm muscle, prevent depolarization by CCh, or cause muscle contracture or histological damage. Venom (3 µg/ml) had a biphasic effect on the frequency of miniature end-plate potentials, but did not affect their amplitude; there was a progressive decrease in the amplitude of evoked end-plate potentials. The amplitude of compound action potentials in mouse sciatic nerve was unaffected by venom (10 µg/ml). Pre-incubation of venom with coralsnake antivenom (Instituto Butantan) at the recommended antivenom:venom ratio did not neutralize the neuromuscular blockade in PND preparations, but total neutralization was achieved with a tenfold greater volume of antivenom. The addition of antivenom after 50% and 80% blockade restored the twitch responses. These results show that M. lemniscatus lemniscatus venom causes potent, irreversible neuromuscular blockade, without myonecrosis. This blockade is apparently mediated by pre- and postsynaptic neurotoxins and can be reversed by coralsnake antivenom
A Clinico-epidemiological Study Of Bites By Spiders Of The Genus Phoneutria.
From January, 1984 to December, 1996, 422 patients (ages 9 m-99 y, median 29 y) were admitted after being bitten by spiders which were brought and identified as Phoneutria spp. Most of the bites occurred at March and April months (29.2%), in the houses (54.5%), during the day (76.5%), and in the limbs (feet 40.9%, hands 34.3%). Upon hospital admission, most patients presented only local complaints, mainly pain (92.1%) and edema (33.1%) and were classified as presenting mild (89.8%), moderate (8.5%) and severe (0.5%) envenomation. Few patients (1.2%) did not present signs of envenomation. Severe accidents were only confirmed in two children (9 m, 3 y). Both developed acute pulmonary edema, and the older died 9 h after the accident. Patients more than 70 year-old had a significantly greater (p<0.05) frequency of moderate envenomations compared to the 10-70-year-old individuals. Proceedings to relief local pain were frequently performed (local anesthesia alone 32.0%, local anesthesia plus analgesics 20.6% and oral analgesics alone 25. 1%). Only 2.3% of the patients (two cases classified as severe and eight as moderate, eight of them in children) were treated with i.v. antiarachnid antivenom. No antivenom early reaction was observed. In conclusion, accidents involving the genus Phoneutria are common in the region of Campinas, with the highest risk groups being children under 10 years of age and adults over 70 years of age. Cases of serious envenomation are rare (0.5%).4217-2
Perurbation expansions for the spiked harmonic oscillator and related series involving the gamma function
We study weak-coupling perturbation expansions for the ground-state energy of
the Hamiltonian with the generalized spiked harmonic oscillator potential V(x)
= Bx^2 + A/x^2 + lambda/x^alpha, and also for the bottoms of the angular
momentum subspaces labelled by ell = 0,1,2 ..., in N-dimensions corresponding
to the spiked harmonic oscillator potential: V(x) = x^2 + lambda/x^alpha, where
alpha is a real positive parameter. A method of Znojil is then applied to
obtain closed form expressions for the sums of some infinite series whose terms
involve ratios and products of gamma functions.Comment: 9 page
Spectrum of the Y=2 Pentaquarks
By assuming a mass formula for the spectrum of the Y=2 pentaquarks, where the
chromo-magnetic interaction plays a main role, and identifying the lightest
state with the Theta^+(1540), we predict a spectrum in good agreement with the
few I=0 and I=1 candidates proposed in the past.Comment: 12 pages, 4 figures, LaTe
Feeding ecology of the leaf fish Monocirrhus polyacanthus (Perciformes: Polycentridae) in a terra firme stream in the Brazilian Amazon
Re-Inventing Public Education:The New Role of Knowledge in Education Policy-Making
This article focuses on the changing role of knowledge in education policy making within the knowledge society. Through an examination of key policy texts, the Scottish case of Integrated Children Services provision is used to exemplify this new trend. We discuss the ways in which knowledge is being used in order to re-configure education as part of a range of public services designed to meet individuals' needs. This, we argue, has led to a 'scientization' of education governance where it is only knowledge, closely intertwined with action (expressed as 'measures') that can reveal problems and shape solutions. The article concludes by highlighting the key role of knowledge policy and governance in orienting education policy making through a re-invention of the public role of education
Early-onset amyloid deposition and cognitive deficits in transgenic mice expressing a double mutant form of APP695
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