545 research outputs found
The use of a task through virtual reality in cerebral palsy using two different interaction devices (concrete and abstract) - a cross-sectional randomized study.
BACKGROUND: Cerebral Palsy (CP) is characterised by variable difficulties in muscular action, resulting in inability of the individual to perform functional movement. An option to provide functionality to the individual with CP is the use of computer innovation. The aim of this paper was to verify if there was any performance improvement in a task performed in a virtual environment and if there was transfer to the task performed in the real environment and vice versa in this population. METHODS: A computer program was developed comprising a motor task, but with two possibilities of user interaction: a) concrete interface (with physical contact): in which the individual touches the computer screen to finish the task and b) abstract interface (no physical contact): in which the individual performs a hand movement in front of the Kinect device. Participants were split into two groups. The experimental group consisted of 28 individuals with CP within the ages of 6 and 15âyears old. The control group included 28 typically developing individuals mirroring the age and sex of the experimental group. RESULTS: Individuals from both groups were able to improve task performance and retain acquired information. The CP group presented worse performance than the control group in all phases of the study. Further findings showed that the CP group presented better performance in the abstract interface than in the concrete interface, whereas, in the control group, the opposite occurred: their best performance was in the concrete. CONCLUSIONS: Motor tasks performed by individuals with CP through an interface with a more virtual environment feature (abstract interface: Kinect) provided better performance when compared to an interface with a more real characteristic (concrete interface: Touchscreen). TRIAL REGISTRATION: ClinicalTrials.gov Identifier - NCT03352440; Date of registration - November 17, 2017
On spin-1 massive particles coupled to a Chern-Simons field
We study spin one particles interacting through a Chern-Simons field. In the
Born approximation, we calculate the two body scattering amplitude considering
three possible ways to introduce the interaction: (a) a Proca like model
minimally coupled to a Chern-Simons field, (b) the model obtained from (a) by
replacing the Proca's mass by a Chern-Simons term and (c) a complex
Maxwell-Chern-Simons model minimally coupled to a Chern-Simons field. In the
low energy regime the results show similarities with the Aharonov-Bohm
scattering for spin 1/2 particles. We discuss the one loop renormalization
program for the Proca's model. In spite of the bad ultraviolet behavior of the
matter field propagator, we show that, up to one loop the model is power
counting renormalizable thanks to the Ward identities satisfied by the
interaction vertices.Comment: 14 pages, 5 figures, revte
Comparison Between Conventional Intervention and Non-immersive Virtual Reality in the Rehabilitation of Individuals in an Inpatient Unit for the Treatment of COVID-19: A Study Protocol for a Randomized Controlled Crossover Trial.
Background: The new human coronavirus that leads to COVID-19 (coronavirus disease 2019) has spread rapidly around the world and has a high degree of lethality. In more severe cases, patients remain hospitalized for several days under treatment of the health team. Thus, it is important to develop and use technologies with the aim to strengthen conventional therapy by encouraging movement, physical activity, and improving cardiorespiratory fitness for patients. In this sense, therapies for exposure to virtual reality (VR) are promising and have been shown to be an adequate and equivalent alternative to conventional exercise programs. Aim: This is a study protocol with the aim of comparing the conventional physical therapy intervention with the use of a non-immersive VR software during COVID-19 hospitalization. Methods: Fifty patients hospitalized with confirmed diagnosis of COVID-19 will be divided in two groups under physiotherapy treatment using conventional or VR intervention: Group A: participants with COVID-19 will start the first day of the protocol with VR tasks in the morning and then in the second period, in the afternoon, will perform the conventional exercises (n = 25) and Group B: participants with COVID-19 will start the first day with conventional exercises in the morning and in the second period, in the afternoon, will perform activity with VR (n = 25). All participants will be evaluated with different motor and physiologic scales before and after the treatment to measure improvements. Conclusion: Considering the importance of benefits from physical activity during hospitalization, VR software shows promise as a potential mechanism for improving physical activity. The results of this study may provide new insights into hospital rehabilitation. Trial Registration: ClinicalTrials.gov, identifier: NCT04537858. Registered on 01 September 2020
Comparison of soft and hard tissue ablation with sub-ps and ns pulse lasers
Tissue ablation with ultrashort laser pulses offers several unique advantages. The nonlinear energy deposition is insensitive to tissue type, allowing this tool to be used for soft and hard tissue ablation. The localized energy deposition lead to precise ablation depth and minimal collateral damage. This paper reports on efforts to study and demonstrate tissue ablation using an ultrashort pulse laser. Ablation efficiency and extent of collateral damage for 0.3 ps and 1000 ps duration laser pulses are compared. Temperature measurements of the rear surface of a tooth section is also presented
ExpressĂŁo da esterilidade feminina e da carpeloidia em mamoeiro sob diferentes ambientes de cultivo protegido.
O presente estudo teve por objetivo avaliar a ocorrĂȘncia de esterilidade feminina e de carpeloidia em mamoeiros hermafroditas 'Baixinho-de-Santa AmĂĄlia' cultivados sob manejo orgĂąnico, em diferentes tipos de ambiente de proteção,e conduzido com ou sem bifurcação do tronco no transcorrer das quatro estaçÔes do ano. Foram construĂdos trĂȘs tipos de estruturas de proteção contĂguas: (i) estufa (cobertura de plĂĄstico); (ii) estufa sombreada (cobertura adicional de tela 'sombrite' - 30% sobre o plĂĄstico), e (iii) telado (cobertura exclusiva de tela 'sombrite' - 30%), ao lado de uma ĂĄrea de ambiente natural, a pleno sol. Nestes locais, foram cultivados, dentro das normas tĂ©cnicas da agricultura orgĂąnica, mamoeiros da cv. Baixinho-de-Santa-AmĂĄlia. Em metade das plantas, abrangendo todos os ambientes de cultivo, a gema apical foi incisada, logo apĂłs a sexagem, visando Ă bifurcação do tronco. Para efeito de anĂĄlise de variĂąncia, foram considerados quatro blocos por ambiente de cultivo, tendo cada bloco trĂȘs repetiçÔes relativas ao modo de condução das plantas (com e sem bifurcação do tronco). Para anĂĄlise estatĂstica, procedeu-se Ă "anĂĄlise conjunta de experimentos", no caso, os ambientes de cultivo. Nos mamoeiros com tronco bifurcado, houve diminuição do nĂșmero de frutos carpeloides e aumento do nĂșmero de flores fĂȘmeas estĂ©reis. No entanto, essa bifurcação nĂŁo influenciou a frequĂȘncia de frutos normais. Durante a primavera (setembro a dezembro), e notadamente na estufa, o maior nĂșmero de frutos carpeloides por planta correlacionou-se a temperaturas mais elevadas, maior amplitude tĂ©rmica e maior vigor vegetativo; jĂĄ, a maior ocorrĂȘncia de flores estaminadas correlacionou-se tambĂ©m a temperaturas elevadas, baixa luminosidade e menor vigor vegetativo. Por outro lado, essas mesmas condiçÔes ambientais e fenolĂłgicas favorĂĄveis Ă carpeloidia aumentaram a quantidade de frutos normais, assim contribuindo positivamente para a produtividade do mamoeiro
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
Search for composite and exotic fermions at LEP 2
A search for unstable heavy fermions with the DELPHI detector at LEP is
reported. Sequential and non-canonical leptons, as well as excited leptons and
quarks, are considered. The data analysed correspond to an integrated
luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV
and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172
GeV and 161 GeV. The search for pair-produced new leptons establishes 95%
confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2,
depending on the channel. The search for singly produced excited leptons and
quarks establishes upper limits on the ratio of the coupling of the excited
fermio
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