544 research outputs found
Avaliação da Estereopsia em Crianças sob Terapêutica Oclusiva por Ambliopia e Relação desta com a Acuidade Visual
Introdução: A ambliopia é a principal causa de diminuição da acuidade visual em crianças. O diagnóstico e tratamento precoces são fundamentais para o sucesso terapêutico. A oclusão continua a ser o tratamento mais utilizado nesta patologia. Objectivos: Este estudo teve como objectivo a avaliação da estereopsia em crianças com ambliopia sob terapêutica oclusiva e a sua relação com a acuidade visual. Material e Métodos: Estudo prospectivo que incluiu 35 crianças com ambliopia, por anisometropia, estrabismo ou ambos, a fazer terapêutica oclusiva. Em cada consulta foi avaliada a melhor acuidade visual corrigida (MAVC) e a estereopsia para perto. Resultados: A idade média no início do estudo era de 6,17 anos (intervalo 3-9 anos) e o seguimento médio foi de 17 meses (intervalo 6-24 meses). Após tratamento com oclusão houve uma melhoria da MAVC média de 0,5 para 0,84 (p<0,001) e da estereopsia para perto de 1148 para 415 segundos de arco (p<0,001). Observou-se uma correlação linear significativa entre a melhoria da AV e da estereopsia (0,001<p<0,01). Conclusão: Podemos dizer que, em crianças com ambliopia, após tratamento com oclusão, a melhoria da acuidade visual está relacionada com uma melhoria da estereopsia
Functional impairment in people with interstitial lung diseases: is one measure enough?
Introduction: Interstitial lung diseases (ILD) comprehend a large
group of lung diseases that include disease settings associated
with sustained progression and leading to respiratory failure, decreased functional status and premature death. Functional status
can be defined as an individual’s ability to perform normal daily
activities required to meet basic needs, fulfill usual roles and
maintain health and well-being. It includes functional capacity,
i.e., an individual’s maximum capacity to perform daily life activities in a standardized environment; and functional performance, i.e., the activities people actually do during the course of
their daily life. Decreased functional status is the most frequent
reported impact by people with ILD and is associated with increased dependence on others, exacerbations and hospital admissions. Yet, little is known how functional status is impaired in
people with ILD.
Objectives: To explore functional impairments in people with ILD.
Methods: A cross-sectional study was conducted with people with
ILD. Age, sex, body mass index (BMI) and lung function were collected. Functional capacity was assessed with the 1-minute sit-tostand test (1-minSTS), the 6-minute walk test (6MWT) and quadriceps maximum voluntary contraction (QMVC). Functional
performance was assessed with the London Chest Activities of Daily
Living (LCADL). Participants’ functional capacity was classified as
impaired if the 1-minSTS, 6MWT and/or QMVC values were below
70% of predicted. Participants’ functional performance was considered impaired if above the cut-off point of 28% of the LCADL. Descriptive statistics were performed.
Results: In total, 156 people with ILD (65 ± 13 years; 51.9% female;
BMI 28.7 ± 6.1 kg/m2
; FVC 79.2 ± 20.1%predicted; DLCO 55.4 ±
21.2%predicted) participated. ILD diagnosis included fibrosis hypersensitivity pneumonitis (43%), idiopathic pulmonary fibrosis (24%),
connective tissue disease-associated ILD (14%), dust-related (1%) and others (17%). Functional capacity was impaired in 55.3%, 23.8%
and 41.8% of the sample assessed with the 1-minSTS, 6MWT and
QMVC, respectively. Functional performance was impaired in 48.5%
of people with ILD.
Conclusions: A large proportion of people with ILD show impairments in functional status, i.e., in capacity, in performance or in
both. Lack of impairment in one measure does not rule out functional status impairment. Patient-centered and comprehensive assessment of functional status seems vital to guide individually tailored interventions and improve this meaningful domain for the
daily life of ILD patients.publishe
Probing the interference between non-linear, axionic and space-time-anisotropy effects in the QED vacuum
We pursue the investigation of a generic non-linear extension of axionic
electrodynamics (ED) in a Carroll-Field-Jackiw (CFJ) scenario that implements
Lorentz-symmetry violation (LSV). The model consists of an arbitrary non-linear
ED action coupled to the axion field in presence of an anisotropy four-vector
that realizes the breaking of Lorentz symmetry under the particle point of
view. The non-linear electromagnetic field is expanded around a constant and
uniform magnetic background up to second order in the propagating photon field.
Our attention is the study of the material properties of the vacuum in the
particular case of a space-like CFJ -vector. The dispersion relations
associated to the plane wave solutions are explicitly worked out in two
situations: the magnetic background perpendicular and parallel to the wave
direction. We extend these results to consider the analysis of the
birefringence phenomenon in presence of non-linearity, the axion and the LSV
manifested through the spatial anisotropy. Three specific proposals of
non-linear ED are contemplated: Euler-Heisenberg, Born-Infeld and the Modified
Maxwell ED. Throughout the paper, we shall justify why we follow the unusual
path of connecting, in a single Lagrangian density, three pieces of physics
beyond the Standard Model, namely, non-linearity, axions and LSV. We anticipate
that we shall not be claiming that the simultaneous introduction of these three
topics beyond the Standard Model will bring new insights or clues for the
efforts to detect axions or to constrain parameters associate to both
non-linear ED and LSV physics . Our true goal is to actually inspect and
describe how axionic, non-linear and LSV effects interfere with one another
whenever physical entities like refraction indices and birefringence are
computed in presence of an external constant and homogeneous magnetic
background.Comment: 27 pages, no figure
The axion-photon mixing in non-linear electrodynamic scenarios
In this contribution, we re-assess some aspects of axionic electrodynamics by
coupling non-linear electromagnetic effects to axion physics. We present a
number of motivations to justify the coupling of the axion to the photon in
terms of a general non-linear extension of the electromagnetic sector. Our
emphasis in the paper relies on the investigation of the constitutive
permittivity and permeability tensors, for which the axion contributes by
introducing dependence on the frequency and wave vector of the propagating
radiation. Also, we point out how the axion mass and the axion-photon-photon
coupling constant contribute to a dispersive behavior of the electromagnetic
waves, in contrast to what happens in the case of non-linear extensions, when
effective refractive indices appear which depend only on the direction of the
propagation with respect to the external fields. The axion changes this picture
by yielding refractive indices with dependence on the wavelength. We apply our
results to the special case of the Born-Infeld Electrodynamics and we show that
it becomes birefringent whenever the axion is coupled. The paper is
supplemented by an Appendix, where we approach the recent discussion on the
controversy in defining the Poynting vector of axionic electrodynamics. We
present our path to tackle the question and give the expressions we work out
for both the Poynting vector and the momentum density transported by the waves.Comment: 30 pages, no figure
Crystallographic and magnetic properties of UFe5.8Al6.2 single crystals
Single crystals of UFe5.8Al6.2 were characterised by X-ray and neutron diffraction, 57Fe Mössbauer spectroscopy and magnetisation. The structure refinement by X-ray and neutron diffraction shows a ThMn12-type structure, the Fe atoms fully occupying the 8f and partially occupying the 8j positions. Mössbauer spectra confirm these occupations and further indicate a magnetic ordering below 293 K. Magnetisation measurements show a ferromagnetic behaviour below 300 K, with a and b as easy directions and a spontaneous magnetisation of 10.4 [mu]B/f.u. at 5 K, due to the Fe occupation of 8j position. These single crystal results significantly differ from those previously obtained in UFe6Al6 polycrystalline samples obtained by melting and annealing.http://www.sciencedirect.com/science/article/B6TJJ-3V7WTYX-N/1/f7893080a7f27a628198f02aeb40fe2
Desilication of MOR zeolite: Conventional versus microwave assisted heating
MOR zeolites were modified via desilication treatments with NaOH, under conventional and microwave heating. The samples were characterized by powder X-ray diffraction, (27)Al and (29)Si NMR spectroscopy. TEM and N(2) adsorption at -196 degrees C. The acidity of the samples and the space available inside the pores were evaluated through a catalytic model reaction, the isomerization of m-xylene, for which the profiles of the coke thermal decomposition were also analyzed. Powder X-ray diffraction and (29)Si and (27)Al MNR results show that in comparison with conventional heating, microwave irradiation (a less time consuming process) leads to identical amount of Si extraction from the zeolite framework. With this treatment. in addition to the customary mesopores development promoted by conventional heating, a partial conversion of the zeolite microporosity into larger micropores, is observed. The microwave irradiated and conventionally heated samples show different catalytic behavior in the m-xylene isomerization model reaction. It was observed that, by controlling the experimental conditions, it is possible to obtain samples with catalytic properties closer to the parent material, which is also confirmed by the respective coke analysis. (C) 2011 Elsevier B.V. All rights reserved
Triple-q octupolar ordering in NpO_2
We report the results of resonant X-ray scattering experiments performed at
the Np M_4,5 edges in NpO_2. Below T_0 = 25 K, the development of long-range
order of Np electric quadrupoles is revealed by the growth of superlattice
Bragg peaks. The electronic transition is not accompanied by any measurable
crystallographic distortion, either internal or external, so the symmetry of
the system remains cubic. The polarization and azimuthal dependence of the
intensity of the resonant peaks is well reproduced assuming Templeton
scattering from a triple-q longitudinal antiferroquadrupolar structure.
Electric quadrupole order in NpO_2 could be driven by the ordering at T_0 of
magnetic octupoles of Gamma_5 symmetry, splitting the Np ground state quartet
and leading to a singlet ground state with zero dipole magnetic moment.Comment: 4 Pages, 3 Figures, submitted to Phys. Rev. Lett. v2: resubmitted
after referee report
Pulmonary rehabilitation in primary health care: an effective intervention even with minimal resources
No abstract available.publishe
Bringing pulmonary rehabilitation closer to the community and keeping its effectiveness
Background: Pulmonary Rehabilitation (PR) is a key evidence-based intervention in the management of chronic respiratory diseases.
Nevertheless, it is still highly inaccessible and underutilised by patients, as most PR programmes are directed to patients with advanced
disease and/or held on a hospital-basis. There is an urgent need to increase access to PR and therefore, new intervention models that can
be more inclusive and closer to patients' homes have been recommended.
Purpose: To evaluate the effects of a community-based PR programme in patients with chronic respiratory diseases.
Methods: A quasi-experimental study was conducted. Patients were recruited from primary health care centres. Patients enrolled in a 12-
week community-based PR programme of exercise training, twice a week, and education and psychosocial support, once every other
week. Outcome measures used to assess effectiveness of the programme were collected pre/post PR. Dyspnoea during activities was
collected with the modified medical research council-dyspnoea scale (mMRC); anxiety and depression symptoms with the Hospital Anxiety
and Depression Scale (HADS); health-related quality of life with the Saint George's Respiratory Questionnaire (SGRQ); quadriceps muscle
strength (QMS) with a handheld dynamometer; functionality with the 1-minute sit-to-stand (1-minSTS); exercise tolerance with the sixminute walk test (6MWT) and functional balance with the Brief Balance Evaluation System Test (Brief-BESTest). Differences were
examined using the Student's t-test or the Wilcoxon test, according to data normality, and effect sizes (ES) were calculated. For the
measures with an established minimal clinically important difference (MCID), an analysis of the number of patients that improved above
that value was conducted.
Results: Fifty-six patients (36 male; 67.0±10.3years; 56.8±3.2% FEV %predicted) with COPD (n=37), asthma (n=11), asthma-COPD
overlap syndrome (n=2), interstitial lung disease (n=2), pneumonitis (n=2), pulmonary fibrosis (n=1), lung transplant due to COPD (n=1)
and bronchiectasis (n=1) participated. After the PR programme, significant improvements were observed in the mMRC (2[0-4] vs. 1[0-3];
p≤0.001; ES=-0.49; 22 (39,3%) patients above the MCID); HADS Anxiety (6.5±3.5 vs. 5.7±3.4;p=0.042; ES=-0.23; 23 (41,1%) patients
above the MCID) and HADS Depression (6.6±4.1 vs. 5.8±3.8; p=0.113; ES=-0.19; 23 (41,1%) patients above the MCID); SGRQ total score
(46.5±19.0 vs. 38.4±16.5; p≤0.001; ES=-0.45; 35 (62,5%) patients above the MCID); QMS (29.3±7.5 vs. 32.9±7.6Kgf; p≤0.001; ES=0.48);
1-minSTS (26±10 vs. 30±11 repetitions; p≤0.001; ES=0.38; 26 (46,4%) patients above the MCID), 6MWT (400.8±116.9 vs. 455.8±118.5m;
p≤0.001; ES=0.47; 40 (71,4%) patients above the MCID), Brief-BESTest (17.2±5.0 vs. post 20.2±3.3; p≤0.001; ES=0.70; 13 (23,2%)
patients above the MCID).
Conclusion(s): Community-based PR programmes are feasible and effective to conduct in patients with chronic respiratory diseases,
providing similar benefits for symptoms, health-related quality of life, lower limb muscle strength, functionality, exercise tolerance and
balance to those well-established for PR programmes carried out in hospital outpatient settings.
Implications: Community-based PR programmes are a feasible and effective way of increasing access to a fundamental intervention for
patients with chronic respiratory diseases.publishe
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