1,933 research outputs found
Contemporary Guarani Shamanisms: âTraditional Medicineâ and Discourses of Native Identity in Brazil
The psychoactive substance known as ayahuasca has long been identified with Amazonian shamanism and traditional medicine. Over the last two decades its use has spread outside this region to urban populations in different parts of the world. This paper examines the adoption of the ritual use of the beverage by the Guarani Indians along the southern coast of Brazil. We argue that this process is related to the growing politics of identity of Brazilian indigenous peoples as well as to public policies that promote cultural diversity. In the case analyzed here, the adoption of ayahuasca is articulated with an ongoing cultural revitalization in activities related to shamanism, health and education and with the specific desires and actions of the leading family in one Guarani village
Vlasov Simulations of Trapping and Inhomogeneity in Raman Scattering
We study stimulated Raman scattering (SRS) in laser-fusion conditions with
the Eulerian Vlasov code ELVIS. Back SRS from homogeneous plasmas occurs in
sub-picosecond bursts and far exceeds linear theory. Forward SRS and re-scatter
of back SRS are also observed. The plasma wave frequency downshifts from the
linear dispersion curve, and the electron distribution shows flattening. This
is consistent with trapping and reduces the Landau damping. There is some
acoustic () activity and possibly electron acoustic scatter.
Kinetic ions do not affect SRS for early times but suppress it later on. SRS
from inhomogeneous plasmas exhibits a kinetic enhancement for long density
scale lengths. More scattering results when the pump propagates to higher as
opposed to lower density.Comment: 4 pages, 6 figures. Submitted to "Journal of Plasmas Physics" for the
conference proceedings of the 19th International Conference on Numerical
Simulation of Plasma
Understanding the impact of antibiotic perturbation on the human microbiome
The human gut microbiome is a dynamic collection of bacteria, archaea, fungi, and viruses that performs essential functions for immune development, pathogen colonization resistance, and food metabolism. Perturbation of the gut microbiome\u27s ecological balance, commonly by antibiotics, can cause and exacerbate diseases. To predict and successfully rescue such perturbations, first, we must understand the underlying taxonomic and functional dynamics of the microbiome as it changes throughout infancy, childhood, and adulthood. We offer an overview of the healthy gut bacterial architecture over these life stages and comment on vulnerability to short and long courses of antibiotics. Second, the resilience of the microbiome after antibiotic perturbation depends on key characteristics, such as the nature, timing, duration, and spectrum of a course of antibiotics, as well as microbiome modulatory factors such as age, travel, underlying illness, antibiotic resistance pattern, and diet. In this review, we discuss acute and chronic antibiotic perturbations to the microbiome and resistome in the context of microbiome stability and dynamics. We specifically discuss key taxonomic and resistance gene changes that accompany antibiotic treatment of neonates, children, and adults. Restoration of a healthy gut microbial ecosystem after routine antibiotics will require rationally managed exposure to specific antibiotics and microbes. To that end, we review the use of fecal microbiota transplantation and probiotics to direct recolonization of the gut ecosystem. We conclude with our perspectives on how best to assess, predict, and aid recovery of the microbiome after antibiotic perturbation
Assessment of the ergogenic effect of caffeine supplementation on mood, anticipation timing, and muscular strength in older adults
The effect of caffeine to promote improvements in mood, cognition, and exercise performance has been well established in young and athletic adults. However, little is known about whether such nutritional ergogenic aids are effective in enhancing psychological well-being, physiological or cognitive performance in older adults. This study assesses the ergogenic effect of caffeine on mood, perceptual-motor coupling, and muscular strength in an older human population. Following a familiarization session, 12 apparently healthy volunteers (nine females and three males; 69 ± 6 years) completed two laboratory visits. "Pre ingestion" trials of mood state Brunel Mood State Inventory (BRUMS) and coincidence anticipation performance (Bassin anticipation timer) at slow (3 mph) and fast (8 mph) stimulus speeds were completed on both visits. Using a randomized, double-blind, cross-over design, participants consumed either caffeine (3 mg/kg body mass) or a placebo. Sixty minutes postingestion participants repeated the trials before completing a set of 10 consecutive repetitions of maximal knee extension using isokinetic dynamometry. Rating of perceived exertion (RPE) was assessed following the fifth and final repetition. Caffeine ingestion significantly improved mood state scores for vigor by 17% (P = 0.009) and reduced absolute error by 35% (P = 0.045) during coincidence anticipation assessment at 8 mph compared to placebo. There were no other significant effects. Caffeine ingestion failed to augment maximal voluntary contraction of the knee extensors and RPE did not prove to be significantly different to from placebo (P > 0.33 in each case). Acute caffeine ingestion may not be an effective ergogenic aid for improving muscular strength in older adults but could possibly be used as a nutrition supplement for enhancing mood and improving cognitive performance in daily living tasks where interceptive timing skills are required
Contingent electric shock as a treatment for challenging behavior for people with intellectual and developmental disabilities : support for the IASSIDD policy statement opposing its use
Issues: The International Association for the Scientific Study of Intellectual and Developmental Disabilities (IASSIDD) is an international group of researchers, clinicians, students, parents, and self-advocates that promotes worldwide research and exchange of information on intellectual and developmental disabilities. IASSIDD recently developed a policy statement regarding their opposition to the use of contingent electric skin shock (CESS) with individuals with challenging behaviour and intellectual and developmental disabilities. To support the policy, the available literature was reviewed to evaluate the efficacy, side effects, generalization, and long-term effectiveness of the procedure as an intervention for challenging behaviour. Findings: The review provides a history that demonstrates that, although CESS can decrease the frequency of challenging behaviour, it comes at a cost in terms of physical and emotional side effects, and questions remain regarding the long-term effectiveness of the procedure. In addition, we raise several ethical and methodological issues that make the research on the use of CESS even more concerning. Conclusions: Although research continues in some countries, these studies are now rare. In fact, in the United States, the Food and Drug Administration has just banned the use of such devices with individuals with self-injury and aggression (Federal Register, 2020). It is hoped that, because there are many other forms of treatment that have shown to be effective for severe challenging behaviour, we can completely avoid the use of CESS
Kinetic Enhancement of Raman Backscatter, and Electron Acoustic Thomson Scatter
1-D Eulerian Vlasov-Maxwell simulations are presented which show kinetic
enhancement of stimulated Raman backscatter (SRBS) due to electron trapping in
regimes of heavy linear Landau damping. The conventional Raman Langmuir wave is
transformed into a set of beam acoustic modes [L. Yin et al., Phys. Rev. E 73,
025401 (2006)]. For the first time, a low phase velocity electron acoustic wave
(EAW) is seen developing from the self-consistent Raman physics. Backscatter of
the pump laser off the EAW fluctuations is reported and referred to as electron
acoustic Thomson scatter. This light is similar in wavelength to, although much
lower in amplitude than, the reflected light between the pump and SRBS
wavelengths observed in single hot spot experiments, and previously interpreted
as stimulated electron acoustic scatter [D. S. Montgomery et al., Phys. Rev.
Lett. 87, 155001 (2001)]. The EAW is strongest well below the phase-matched
frequency for electron acoustic scatter, and therefore the EAW is not produced
by it. The beating of different beam acoustic modes is proposed as the EAW
excitation mechanism, and is called beam acoustic decay. Supporting evidence
for this process, including bispectral analysis, is presented. The linear
electrostatic modes, found by projecting the numerical distribution function
onto a Gauss-Hermite basis, include beam acoustic modes (some of which are
unstable even without parametric coupling to light waves) and a strongly-damped
EAW similar to the observed one. This linear EAW results from non-Maxwellian
features in the electron distribution, rather than nonlinearity due to electron
trapping.Comment: 15 pages, 16 figures, accepted in Physics of Plasmas (2006
Sediment provenance in the Shudu Lake basin, northwest Yunnan Province, China, as revealed by composite fingerprinting
Composite fingerprinting represents an effective method of reconstructing sediment-source changes in remote areas where long-term hydrological and sediment accretion records do not exist. A ca. 50-year record of sediment deposition was determined for a small catchment at Shudu, situated in northwest Yunnan Province, China. Woodland, pasture, shrubland and channel bank material are identified as the most likely sediment sources and this was confirmed using a composite sediment fingerprinting approach. Based on the findings of the fingerprinting technique, variations in the geochemical signature associated with lacustrine sediment deposits indicate that 49.2 % of the total catchment sediment yield over an approximate 50-year period originated from channel banks. In contrast, 19.2 % originated from pasture, 18.6 % originated from shrubland, and 13 % from woodland. The relative contributions of eroded sediment from both woodland and shrubland have generally remained stable over the period investigated, whereas the contribution of material from pasture has increased over recent decades. This is tentatively attributed to increased grazing pressure, which is probably due to increased stocking densities which have gradually exceeded the carrying capacity and regenerative capabilities of the available grassland
'Skating on thin ice?' consultant surgeon's contemporary experience of adverse surgical events
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