5,242 research outputs found
Atividade microbiana do solo sob diferentes cultivos irrigados em um Argissolo Vermelho Amarelo distrófico no Submédio São Francisco.
Este trabalho tem por objetivo avaliar a atividade biológica do solo sob diferentes cultivos com uso de irrigação e sua comparação com áreas de Caatinga. As amostras foram coletadas em novembro de 2006 em áreas com cultivo de manga, uva, culturas anuais, banana e em reserva de vegetação natural, no Campo Experimental da Embrapa Semi-¡rido no Distrito Irrigado de Bebedouro
The optical counterpart of the bright X-ray transient Swift J1745-26
We present a 30-day monitoring campaign of the optical counterpart of the
bright X-ray transient Swift J1745-26, starting only 19 minutes after the
discovery of the source. We observe the system peaking at i' ~17.6 on day 6
(MJD 56192) to then decay at a rate of ~0.04 mag/day. We show that the optical
peak occurs at least 3 days later than the hard X-ray (15-50 keV) flux peak.
Our measurements result in an outburst amplitude greater than 4.3 magnitudes,
which favours an orbital period < 21 h and a companion star with a spectral
type later than ~ A0. Spectroscopic observations taken with the GTC-10.4 m
telescope reveal a broad (FWHM ~ 1100 km/s), double-peaked H_alpha emission
line from which we constrain the radial velocity semi-amplitude of the donor to
be K_2 > 250 km/s. The breadth of the line and the observed optical and X-ray
fluxes suggest that Swift J1745-26 is a new black hole candidate located closer
than ~7 kpc.Comment: 5 pages, 4 figures, accepted for publication in MNRA
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Phase Stability under Irradiation of Precipitates and Solid Solutions in Model ALloys and in ODS Alloys Relevant for Gen IV
The overall objective of this program is to investigate the irradiation-altered phase stability of oxide precipitates in ODS steels and of model alloy solid solutions of associated systems. This information can be used to determine whether the favorable mechanical propertiies of these steels are maintained under irradiation, thus addressing one of the main materials research issues for this class of steels as identified by the GenIV working groups. The research program will also create fundamental understanding of the irradiation precipitation/dissolution problem by studying a "model" system in which the variables can be controlled and their effects understood individually
Population pharmacokinetics and pharmacodynamics of investigational regimens' drugs in the TB-PRACTECAL clinical trial (the PRACTECAL-PKPD study): a prospective nested study protocol in a randomised controlled trial
Introduction Drug-resistant
tuberculosis (TB) remains
a global health threat, with little over 50% of patients
successfully treated. Novel regimens like the ones being
studied in the TB-PRACTECAL
trial are urgently needed.
Understanding anti-TB
drug exposures could explain the
success or failure of these trial regimens. We aim to study
the relationship between the patients’ exposure to anti-TB
drugs in TB-PRACTECAL
investigational regimens and their
treatment outcomes.
Methods and analysis Adults with multidrug-resistant
TB randomised to investigational regimens in TB-PRACTECAL
will be recruited to a nested pharmacokinetic-pharmacodynamic
(PKPD) study. Venous blood samples
will be collected at 0, 2 and 23 hours postdose on day
1 and 0, 6.5 and 23 hours postdose during week 8 to
quantify drug concentrations in plasma. Trough samples
will be collected during week 12, 16, 20 and 24 visits.
Opportunistic samples will be collected during weeks
32 and 72. Drug concentrations will be quantified using
liquid chromatography-tandem
mass spectrometry.
Sputum samples will be collected at baseline, monthly to
week 24 and then every 2 months to week 108 for MICs
and bacillary load quantification. Full blood count, urea
and electrolytes, liver function tests, lipase, ECGs and
ophthalmology examinations will be conducted at least
monthly during treatment.
PK and PKPD models will be developed for each drug with
nonlinear mixed effects methods. Optimal dosing will be
investigated using Monte-Carlo
simulations.
Ethics and dissemination The study has been approved
by the Médecins sans Frontières (MSF) Ethics Review
Board, the LSHTM Ethics Committee, the Belarus RSPCPT
ethics committee and PharmaEthics and the University of
Witwatersrand Human Research ethics committee in South
Africa. Written informed consent will be obtained from all
participants. The study results will be shared with public
health authorities, presented at scientific conferences and
published in a peer-reviewed
journal.
Trial registration number NCT04081077; Pre-results
Effects of four food dyes on development of three model species, Cucumis sativus, Artemia salina and Danio rerio: Assessment of potential risk for the environment
Food dyes, or color additives, are chemicals added to industrial food products and in domestic cooking to improve the perceived flavor and attractiveness. Of natural and synthetic origin, their safety has been long discussed, and concern for human safety is now clearly manifested by warnings added on products labels. Limited attention, however, has been dedicated to the effects of these compounds on aquatic flora and fauna. For this reason, the toxicity of four different commercially available food dyes (cochineal red E120, Ponceau red E124, tartrazine yellow E102 and blue Patent E131) was assessed on three different model organisms, namely Cucumis sativus, Artemia salina and Danio rerio that occupy diverse positions in the trophic pyramid. The evidence collected indicates that food dyes may target several organs and functions, depending on the species. C. sativus rate of germination was increased by E102, while root/shoot ratio was ∼20% reduced by E102, E120 and E124, seed total chlorophylls and carotenoids were 15–20% increased by E120 and 131, and total antioxidant activity was ∼25% reduced by all dyes. Mortality and low mobility of A. salina nauplii were increased by up to 50% in presence of E124, E102 and E131, while the nauplii phototactic response was significantly altered by E102, E120 and E124. Two to four-fold increases in the hatching percentages at 48 h were induced by E124, E102 and E131 on D. rerio, associated with the occurrence of 20% of embryos showing developmental defects. These results demonstrated that the food dyes examined are far from being safe for the aquatic organisms as well as land organisms exposed during watering with contaminated water. The overall information obtained gives a realistic snapshot of the potential pollution risk exerted by food dyes and of the different organism' ability to overcome the stress induced by contamination
Dynamics around the binary system (65803) Didymos
Didymos and Dimorphos are primary and secondary, respectively, asteroids who
compose a binary system that make up the set of Near Earth Asteroids (NEAs).
They are targets of the Double Asteroid Redirection Test (DART), the first test
mission dedicated to study of planetary defense, for which the main goal is to
measure the changes caused after the secondary body is hit by a kinect
impactor. The present work intends to conduct a study, through numerical
integrations, on the dynamics of massless particles distributed in the vicinity
of the two bodies. An approximate shape for the primary body was considered as
a model of mass concentrations (mascons) and the secondary was considered as a
massive point. Our results show the location and size of stable regions, and
also their lifetime
“Surfing in the cell” - an investigative game for teaching cytoskeleton concepts for undergraduate students
The educational role of games becomes evident as students are more active, able to take decisions, solve problems and react to the results of their own decisions. The educative board game Discovering the Cell is based on problem-solving learning. This game challenges students to collect, discuss and interpret clues in order to decipher a question. In this work we evaluated the game as a tool for teaching health sciences undergraduate students from Rio de Janeiro. In a questionnaire-based analysis, students demonstrated great acceptance for this strategy and the majority of them were able to solve the Case tested, as well as applying the learned content to answer a related question. Taken together, our results indicate the acceptance and suitability of the game as an alternative strategy to help teaching cell and molecular biology to undergraduate students
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