2,498 research outputs found
Análises macro da deformabilidade de solo-cal no domínio das pequenas deformações
Lusical, Université Libré de Bruxelles , Lhoist R&
Balance in Family Triads:How Intergenerational Relationships Affect the Adult Sibling Relationship
In order to understand the interdependency between intergenerational and adult sibling relationships, a family systems perspective is applied to identify a smaller?empirically analyzable?relational unit of analysis, that is, the sibling?parent?sibling triad. Using balance theory, triadic configurations are derived that represent enhancement, compensation, and loyalty conflicts. The hypotheses are tested for three relational dimensions: support exchange, contact, and conflict. Multilevel analyses of 549 sibling?parent?sibling triads from the Netherlands Kinship Panel data show strong evidence for enhancement, whereas some indication was obtained for sibling relationships being affected by loyalty conflicts. The results underscore and substantiate interdependency between intergenerational and adult sibling relationships
3-200 keV spectral states and variability of the INTEGRAL Black Hole binary IGR J17464-3213
On March 2003, IBIS, the gamma-ray imager on board the INTEGRAL satellite,
detected an outburst from a new source, IGR J17464-3213, that turned out to be
a HEAO-1 transient, H1743-322. In this paper we report on the high energy
behaviour of this BHC studied with the three main instruments onboard INTEGRAL.
The data, collected with unprecedented sensitivity in the hard X-Ray range,
show a quite hard Comptonised emission from 3 keV up to 150 keV during the
rising part of the source outburst, with no thermal emission detectable. A few
days later, a prominent soft disk multicolour component appears, with the hard
tail luminosity almost unchanged: 10-9 erg*cm-2*s-1. Two months later, during a
second monitoring campaign near the end of the outburst, the observed disk
component was unchanged. Conversely, the Comptonised emission from the
central-hot part of the disk reduced by a factor of 10. We present here its
long term behaviour in different energy ranges and the combined JEM-X, SPI and
IBIS wide band spectral evolution of this source.Comment: 12 pages, 4 figures, accepted for pubblication in AP
Improved correction of VIPERS angular selection effects in clustering measurements
AbstractClustering estimates in galaxy redshift surveys need to account and correct for the way targets are selected from the general population, as to avoid biasing the measured values of cosmological parameters. The VIMOS Public Extragalactic Redshift Survey (VIPERS) is no exception to this, involving slit collisions and masking effects. Pushed by the increasing precision of the measurements, e.g. of the growth rate f, we have been re-assessing these effects in detail. We present here an improved correction for the two-point correlation function, capable to recover the amplitude of the monopole of the two-point correlation function ξ(r) above 1 h-1 Mpc to better than 2
Pulmonary Effects of Neonatal Hydrocortisone Treatment in Ventilator-Dependent Preterm Infants
Background/Objective. Hydrocortisone, administered to ventilated preterm neonates to facilitate extubation, has no adverse long-term effects, but short-term pulmonary effects have not been described previously. In the present study, we analyzed effects of hydrocortisone on ventilator settings and FiO2 in ventilator-dependent preterm infants. Patients and Methods. Fifty-five preterm children were included in this retrospective cohort study. Hydrocortisone was administered at a postnatal age of > 7 days to treat chronic lung disease (CLD). Ventilator settings before and after hydrocortisone administration were recorded as well as FiO2 at 36 weeks' gestational age. Presence of cerebral palsy was assessed at a mean corrected age of 24.1 months. Results. Hydrocortisone administered at a median postnatal age of 14 days significantly reduced FiO2 from a median of 0.39 to 0.30, mean airway pressure (MAP) from a median of 10.0 cm H2O to 7.6 cm H2O, and PaCO2 from a median of 53.5 mmHg to 47 mmHg. Extubation was achieved in all patients. CLD at 36 weeks was present in 11 of the 52 patients (21.1%). None developed cerebral palsy. Conclusions. Hydrocortisone was effective in reducing the FiO2, MAP, and PaCO2 and facilitated extubation. Hydrocortisone was not associated with cerebral palsy
Flow-dependency of exhaled nitric oxide in children with asthma and cystic fibrosis
The concentration of nitric oxide in exhaled air, a marker of airway
inflammation, depends critically on the flow of exhalation. Therefore, the
aim of this study was to determine the effect of varying the flow on
end-expiratory NO concentration and NO output in children with asthma or
cystic fibrosis (CF) and in healthy children. Nineteen children with
stable asthma, 10 with CF, and 20 healthy children exhaled from TLC while
controlling expiratory flow by means of a biofeedback signal at
approximately 2, 5, 10 and 20% of their vital capacity per second. NO was
measured in exhaled air with a chemiluminescence analyser. Comparisons
between the three groups were made by analysing the NO concentration at
the endexpiratory plateau and by calculating NO output at different flows.
Exhaled NO decreased with increasing flow in all children. Children with
asthma had significantly higher NO concentrations than healthy children,
but only at the lowest flows. Asthmatics using inhaled steroids (n=13)
tended to have lower median exhaled NO than those without steroids. The
slope of linearized (log-log transformed) NO/flow plots was significantly
steeper in asthmatics than in healthy controls. CF patients had a
significantly lower NO concentration and output over the entire flow range
studied, compared to asthmatic and control subjects, with a similar
NO/flow slope as control subjects. In conclusion, the nitric oxide
concentration in exhaled air is highly flow-dependent, and the nitric
oxide-flow relationship differs between asthmatics versus cystic fibrosis
patients and control subjects. Assessment of the nitric oxide/flow
relationship may help in separating asthmatics from normal children
A perturbative solution for gravitational waves in quadratic gravity
We find a gravitational wave solution to the linearized version of quadratic
gravity by adding successive perturbations to the Einstein's linearized field
equations. We show that only the Ricci squared quadratic invariant contributes
to give a different solution of those found in Einstein's general relativity.
The perturbative solution is written as a power series in the
parameter, the coefficient of the Ricci squared term in the quadratic
gravitational action. We also show that, for monochromatic waves of a given
angular frequency , the perturbative solution can be summed out to give
an exact solution to linearized version of quadratic gravity, for
.
This result may lead to implications to the predictions for gravitational
wave backgrounds of cosmological origin.Comment: 9 pages, to appear in CQ
Participação dos professores na escola
Na proximidade do século XXI, a Escola Portuguesa vive momentos de incerteza, de preocupação e desafio face ao futuro.
Estamos perante uma sociedade que não se compadece com uma escola parada no tempo, mas, sim, exige uma escola activa, dinâmica e aberta ao meio.
Pretende-se uma escola que desenvolva uma cultura de participação1, que saiba partilhar a educação com a família (principal entidade, responsável pela educação), com os trabalhadores não docentes, com a comunidade envolvente e assim todos possam contribuir para o desenvolvimento pleno e harmonioso da personalidade dos indivíduos, tornando-os cidadãos mais responsáveis e livres na sociedade. É este tipo de escola que é preconizada pela Lei de Bases (Lei nº46 / 86, de 14 de Outubro) e que exige uma mudança do Sistema Tradicional de Ensino.
Por isso, a escola de hoje exige novas posturas, novas responsabilidades de todos os que nela intervêm e contribuem para uma melhoria do ensino, quer sejam professores, pais ou outros. Mas, o papel do professor, como principal impulsionador e dinamizador, é e será determinante para o sucesso de qualquer reforma do sistema educativo.
O professor assume o papel primordial de dinamizador de participação e de mobilização de todos os outros intervenientes, no sentido de os levar a darem o seu contributo e a assumirem a sua cota parte de responsabilidade na educação, para que a escola possa realizar os seus objectivos.
A escola é um local onde se trocam experiências, onde todos os que aí participam vivem um pouco ou grande parte da sua vida. Por isso, é imprescindível que cada um se sinta parte integrante dela.
Assim, abordaremos a escola como um espaço de interacção, bem como as formas de participação dos seus intervenientes. Porque compreender a acção dos que fazem a escola leva-nos a conhecer os estatutos de cada membro e os papéis a eles associados, as normas organizacionais que orientam a interacção e o contributo de cada um para a prossecução das actividades. É na conjugação destes factores que se definem as formas de cada um estar na escola
- …