3,322 research outputs found
A cooling system for a hybrid PV/thermal linear concentrator
This paper presents the thermal evaluation of an evacuated PVT collector designed to operate under concentrated radiation (15 suns). Finite volume 3D numerical computations have been carried out in order to study the thermal characteristics of different rectangular cross section aluminium pipes and to test the performance of the PVT collector with several laminar flow rates. Experiments with the same laminar flows show the same behavior than in the numerical results
Stimuli in 3 Acts: A normative study on action-statements, action videos and object photos
The study of action observation and imagery, separately and combined, is expanding in diverse research areas (e.g., sports
psychology, neurosciences), making clear the need for action-related stimuli (i.e., action statements, videos, and pictures).
Although several databases of object and action pictures are available, norms on action videos are scarce. In this study, we
validated a set of 60 object-related everyday actions in three diferent formats: action-statements, and corresponding dynamic
(action videos) and static (object photos) stimuli. In Study 1, ratings of imageability, image agreement, action familiarity,
action frequency, and action valence were collected from 161 participants. In Study 2, a diferent sample of 115 participants
rated object familiarity, object valence, and object-action prototypicality. Most actions were rated as easy to imagine, familiar, and neutral or positive in valence. However, there was variation in the frequency with which participants perform these
actions on a daily basis. High agreement between participants’ mental image and action videos was also found, showing that
the videos depict a conventional way of performing the actions. Objects were considered familiar and positive in valence.
High ratings on object-action prototypicality indicate that the actions correspond to prototypical actions for most objects.
3ActStimuli is a comprehensive set of stimuli that can be useful in several research areas, allowing the combined study of
action observation and imagery.info:eu-repo/semantics/publishedVersio
Exact and Approximate Formulas for Neutrino Mixing and Oscillations with Non-Standard Interactions
We present, both exactly and approximately, a complete set of mappings
between the vacuum (or fundamental) leptonic mixing parameters and the
effective ones in matter with non-standard neutrino interaction (NSI) effects
included. Within the three-flavor neutrino framework and a constant matter
density profile, a full set of sum rules is established, which enables us to
reconstruct the moduli of the effective leptonic mixing matrix elements, in
terms of the vacuum mixing parameters in order to reproduce the neutrino
oscillation probabilities for future long-baseline experiments. Very compact,
but quite accurate, approximate mappings are obtained based on series
expansions in the neutrino mass hierarchy parameter \eta \equiv \Delta
m^2_{21}/\Delta m^2_{31}, the vacuum leptonic mixing parameter s_{13} \equiv
\sin\theta_{13}, and the NSI parameters \epsilon_{\alpha\beta}. A detailed
numerical analysis about how the NSIs affect the smallest leptonic mixing angle
\theta_{13}, the deviation of the leptonic mixing angle \theta_{23} from its
maximal mixing value, and the transition probabilities useful for future
experiments are performed using our analytical results.Comment: 29 pages, 8 figures, final version published in J. High Energy Phy
Tumor de Células Germinativas Primário da Próstata – descrição de um caso raro
info:eu-repo/semantics/publishedVersio
Coilgun Acceleration Model Containing Multiple Interacting Coils
A coilgun operates by pulsing current through an axially-arranged series of independently-controlled coils inductively interacting with a small, electrically-conductive, azimuthally-symmetric projectile to accelerate it to high velocities. The electrical circuits are programmed to pulse current through the coils in such a way so as to impart further electromagnetic acceleration in each stage. A method is developed to calculate the mutual inductance between the coils and between each coil and the projectile. These terms are used to write a system of first-order ordinary differential equations governing the projectile velocity and the current flow in each coil. While the inclusion of the electromagnetic interactions between coils significantly complicates the equation set as more coil sets are included in the problem, casting the problem symbolically in mass matrix form permits solution using standard numerical Runge-Kutta techniques. Comparing a projectile with a single-turn to that comprised of nine-turns, the inductance of the former is much smaller, but this leads to a greater induced projectile current. The lower inductance and greater current appear to offset each other with little difference in the acceleration profile for the two cases. For the limited cases studied, coils with a discharge half-cycle equal to the time for a projectile to transit from one coil to the next yield increased efficiency
Probing Non-Standard Neutrino Interactions with Neutrino Factories
We discuss the sensitivity reach of a neutrino factory measurement to
non-standard neutrino interactions (NSI), which may exist as a low-energy
manifestation of physics beyond the Standard Model. We use the muon appearance
mode \nu_e --> \nu_\mu and consider two detectors, one at 3000 km and the other
at 7000 km.
Assuming the effects of NSI at the production and the detection are
negligible, we discuss the sensitivities to NSI and the simultaneous
determination of \theta_{13} and \delta by examining the effects in the
neutrino propagation of various systems in which two NSI parameters
\epsilon_{\alpha \beta} are switched on. The sensitivities to off-diagonal
\epsilon's are found to be excellent up to small values of \theta_{13}.
We demonstrate that the two-detector setting is powerful enough to resolve
the \theta_{13}-NSI confusion problem. We believe that the results obtained in
this paper open the door to the possibility of using neutrino factory as a
discovery machine for NSI while keeping its primary function of performing
precision measurements of the lepton mixing parameters.Comment: 47 pages, 22 figures. Color version of Figs. 18, 19 and 22 can be
found in the article published in JHE
Perturbation Theory of Neutrino Oscillation with Nonstandard Neutrino Interactions
We discuss various physics aspects of neutrino oscillation with non-standard
interactions (NSI). We formulate a perturbative framework by taking \Delta
m^2_{21} / \Delta m^2_{31}, s_{13}, and the NSI elements \epsilon_{\alpha
\beta} (\alpha, \beta = e, \mu, \tau) as small expansion parameters of the same
order \epsilon. Within the \epsilon perturbation theory we obtain the S matrix
elements and the neutrino oscillation probability formula to second order
(third order in \nu_e related channels) in \epsilon. The formula allows us to
estimate size of the contribution of any particular NSI element
\epsilon_{\alpha beta} to the oscillation probability in arbitrary channels,
and gives a global bird-eye view of the neutrino oscillation phenomena with
NSI. Based on the second-order formula we discuss how all the conventional
lepton mixing as well as NSI parameters can be determined. Our results shows
that while \theta_{13}, \delta, and the NSI elements in \nu_e sector can in
principle be determined, complete measurement of the NSI parameters in the
\nu_\mu - \nu_\tau sector is not possible by the rate only analysis. The
discussion for parameter determination and the analysis based on the matter
perturbation theory indicate that the parameter degeneracy prevails with the
NSI parameters. In addition, a new solar-atmospheric variable exchange
degeneracy is found. Some general properties of neutrino oscillation with and
without NSI are also illuminated.Comment: manuscript restructured, discussion of new type of parameter
degeneracy added. 47 page
Dexamethasone Treatment Reverses Cognitive Impairment but Increases Brain Oxidative Stress in Rats Submitted to Pneumococcal Meningitis
Pneumococcal meningitis is associated with a significant mortality rate and neurologic sequelae. The animals received either 10 μL of saline or a S. pneumoniae suspension and were randomized into different groups: sham: placebo with dexamethasone 0.7 mg/kg/1 day; placebo with dexamethasone 0.2 mg/kg/7 days; meningitis groups: dexamethasone 0.7 mg/kg/1 day and dexamethasone 0.2 mg/kg/7 days. Ten days after induction we evaluated memory and oxidative stress parameters in hippocampus and cortex. In the step-down inhibitory avoidance task, we observed memory impairment in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The lipid peroxidation was increased in hippocampus in the meningitis groups with dexamethasone and in cortex only in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The protein carbonyl was increased in hippocampus in the meningitis groups with dexamethasone and in cortex in the meningitis groups with and without dexamethasone. There was a decrease in the proteins integrity in hippocampus in all groups receiving treatment with dexamethasone and in cortex in all groups with dexamethasone (0.7 mg/kg/1 day). The mitochondrial superoxide was increased in the hippocampus and cortex in the meningitis group with dexamethasone 0.2 mg/kg/7 days. Our findings demonstrate that dexamethasone reverted cognitive impairment but increased brain oxidative stress in hippocampus and cortex in Wistar rats ten days after pneumococcal meningitis induction
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