63 research outputs found
Doença Renal na Região Autónoma da Madeira: Experiência de Vinte e Sete Anos de Biópsias de Rim Nativo
Introduction: Renal biopsy plays an essential role either in the diagnosis or in the prognosis of patients with renal disease. In order to assess its epidemiology and evolution in Madeira Islands, we analysed twenty-seven years of native kidney biopsies. Methods: We performed a retrospective analysis of clinical records, including
histological revision from 1986 to 2012, totalling 315 native kidney biopsies. They were assessed regarding the temporal evolution both for the quality/indications for renal biopsy and for the patterns of kidney disease.
Results: A total of 315 native kidney biopsies were analysed. The patients’ mean age was of 40.8 ± 18.4 years and 50.5%(n = 159) were males. The most common indications for renal biopsy were nephrotic syndrome
(36.2%, n = 114) and acute kidney injury (20.0%, n = 63). Among primary glomerular diseases (41.5%, n = 115) the most common were IgA nephropathy (26.1%, n = 30) and focal-segmental glomerulosclerosis (17.4%,
n = 20) and among secondary glomerular diseases (31.4%, n = 87), lupus nephritis (51.7%, n = 45) and amyloidosis
(20.7%, n = 18). Statistical analysis revealed significant correlation between gender and major pathological diagnosis (Fisher’s exact test, p <.01) and between indications for renal biopsy and major pathological diagnosis (χ2, p <.01). Regarding the temporal evolution, no statistically significant differences were found in the number of renal biopsies (χ2, p =.193), number of glomeruli per sample (Fisher’s exact test, p =.669), age
(Kruskal-Wallis, p =.216), indications for renal biopsy (χ2, p =.106) or major pathological diagnosis groups (χ2,p =.649). However, considering the specific clinico-pathological diagnoses and their temporal variation, a statistically significant difference (Fisher’s exact test, p <.05) was found for lupus nephritis and membranous
nephropathy with an increasing incidence and for amyloidosis with an opposite tendency. Discussion: The review of the native kidney biopsies from a population with particular characteristics, geographically isolated,
such as those from Madeira Islands, showed parallel between epidemiological numbers referring to other European subpopulations, allowing simultaneously a comprehensive approach to our renal biopsy policies
Wavelet application to the magnetic field turbulence in the upstream region of the Martian bow shock
Stability of stationary and time-varying nongyrotropic particle distributions
The ubiquity of nongyrotropic particle
populations in space plasmas warrants the study of their characteristics, in
particular their stability. The unperturbed nongyrotropic distribution functions
in homogeneous media without sources and sinks (closed phase space) must be
rotating and time-varying (TNG), whereas consideration of open phase spaces
allows for the occurrence of homogeneous and stationary distributions (SNG). The
free energy brought about by the introduction of gyrophase organization in a
particle population can destabilize otherwise thoroughly stable magnetoplasmas
(or, a fortiori, enhance pre-existing gyrotropic instabilities) and feed
intense wave growth both in TNG and SNG environments: The nongyrotropic
(electron or ion) species can originate unstable coupling among the gyrotropic
characteristic waves. The stability properties of these two types of homogeneous
nongyrotropy shall be contrasted for parallel (with respect to the ambient
magnetic field) and perpendicular propagation, and their potential role as wave
activity sources shall be illustrated resorting to solutions of the appropriate
dispersion equations and numerical simulations.Key words. Space plasma physics (waves and
instabilities) · Magnetospheric physics (plasma waves and instabilities) ·
Interplanetary physics (plasma waves and turbulence
Stability of stationary and time-varying nongyrotropic particle distributions
Abstract. The ubiquity of nongyrotropic particle populations in space plasmas warrants the study of their characteristics, in particular their stability. The unperturbed nongyrotropic distribution functions in homogeneous media without sources and sinks (closed phase space) must be rotating and time-varying (TNG), whereas consideration of open phase spaces allows for the occurrence of homogeneous and stationary distributions (SNG). The free energy brought about by the introduction of gyrophase organization in a particle population can destabilize otherwise thoroughly stable magnetoplasmas (or, a fortiori, enhance pre-existing gyrotropic instabilities) and feed intense wave growth both in TNG and SNG environments: The nongyrotropic (electron or ion) species can originate unstable coupling among the gyrotropic characteristic waves. The stability properties of these two types of homogeneous nongyrotropy shall be contrasted for parallel (with respect to the ambient magnetic ®eld) and perpendicular propagation, and their potential role as wave activity sources shall be illustrated resorting to solutions of the appropriate dispersion equations and numerical simulations. Key words. Space plasma physics (waves and instabilities) Magnetospheric physics (plasma waves and instabilities) Interplanetary physics (plasma waves and turbulence)
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