Internal carotid and vertebral artery dissections — a comparison of clinical, radiological and prognostic characteristics

Aim of study. To examine whether baseline characteristics, potential risk factors, clinical symptoms, radiological presentation, and long-term outcomes differ between internal carotid artery dissection (ICAD) and vertebral artery dissection (VAD).Clinical rationale for study. Cervical artery dissection (CeAD) is a major cause of cerebral ischaemia in young adults. Its clinical course is highly variable, resulting in challenges in making a proper diagnosis.Methods. We performed a retrospective analysis of 31 patients (mean age 42.2 years) with CeAD (18 with ICAD, 13 with VAD) treated in our neurology department from 2008 to 2018. Appropriate imaging confirmed the diagnosis of CeAD.Results. Patients with ICAD presented Horner syndrome significantly more often (44.4% vs 7.6%; p = 0.04). Patients with VAD more often had ischaemic events (ischaemic stroke, TIA or transient blindness) (84.6% vs 44.6%; p = 0.0032). Ischaemic stroke was more severe in patients with ICAD [(median NIHSS 6, interquartile range 4–12) vs VAD (median NIHSS 4, interquartile range 1.5–5.5), p = 0,03]. Occlusion occurred more often in patients with VAD (69.2% vs 22.2%; p = 0.013). Most patients had a favourable outcome (mRS 0–2).Conclusions and clinical implications. In a series of patients with CeAD, we observed significant differences between VAD and ICAD in terms of clinical symptoms and radiological features

Habitat-specific benthic metabolism in a Mediterranean-type intermittent stream

A modified flow-through chamber method was used to measure gross primary production (GPP), net primary production (NPP), community respiration (CR) and associated environmental variables in an intermittent Mediterranean-type stream in Southern Portugal. Three common types of in stream habitats were targeted: cobble (C), cobble covered with filamentous algae (C+A) and leaf litter (LL). NPP, GPP and CR differed significantly among all three habitats. GPP increased with chlorophyll a and, less strongly, with photosynthetic active radiation and, therefore, was highest in C+A habitat. The highest CR was in LL and its variation was best determined by ash-free dry mass (AFDM) of plant litter. Higher respiration in LL was related to heterotrophic activity and, to a lesser extent, to autotrophic respiration associated with periphyton. We observed a decrease of production efficiency of primary producers with AFDM in C+A and C habitats. Our results demonstrate that each habitat type should be considered as a discrete metabolic entity and that particular sets of environmental factors are responsible for habitat specific metabolic responses. Scaling up measurements from discrete habitat patches to the entire reach or stream should not be done by extrapolating the results of a single habitat type and will require quantification of habitat coverage, at the appropriate scale

Long-Term Patterns in the Population Dynamics of Daphnia longispina, Leptodora kindtii and Cyanobacteria in a Shallow Reservoir: A Self-Organising Map (SOM) Approach.

The recognition of long-term patterns in the seasonal dynamics of Daphnia longispina, Leptodora kindtii and cyanobacteria is dependent upon their interactions, the water temperature and the hydrological conditions, which were all investigated between 1999 and 2008 in the lowland Sulejow Reservoir. The biomass of cyanobacteria, densities of D. longispina and L. kindtii, concentration of chlorophyll a and water temperature were assessed weekly from April to October at three sampling stations along the longitudinal reservoir axis. The retention time was calculated using data on the actual water inflow and reservoir volume. A self-organising map (SOM) was used due to high interannual variability in the studied parameters and their often non-linear relationships. Classification of the SOM output neurons into three clusters that grouped the sampling terms with similar biotic states allowed identification of the crucial abiotic factors responsible for the seasonal sequence of events: cluster CL-ExSp (extreme/spring) corresponded to hydrologically unstable cold periods (mostly spring) with extreme values and highly variable abiotic factors, which made abiotic control of the biota dominant; cluster CL-StSm (stable/summer) was associated with ordinary late spring and summer and was characterised by stable non-extreme abiotic conditions, which made biotic interactions more important; and the cluster CL-ExSm (extreme/summer), was associated with late spring/summer and characterised by thermal or hydrological extremes, which weakened the role of biotic factors. The significance of the differences between the SOM sub-clusters was verified by Kruskal-Wallis and post-hoc Dunn tests. The importance of the temperature and hydrological regimes as the key plankton-regulating factors in the dam reservoir, as shown by the SOM, was confirmed by the results of canonical correlation analyses (CCA) of each cluster. The demonstrated significance of hydrology in seasonal plankton dynamics complements the widely accepted pattern proposed by the plankton succession model for lakes, the PEG (Plankton Ecology Group), and may be useful for the formulation of management decisions in dam reservoirs

Indicator macroinvertebrate species in a temporary Mediterranean river: recognition of patterns in binary assemblage data with a Kohonen artificial neural network

Current classifications used in bioassessment programs, as defined by the Water Framework Directive (WFD), do not sufficiently capture the variability present in temporary Mediterranean streams. This may result in inaccurate evaluation of the water quality biological metrics and difficulties in setting reference conditions. The aim of the study was to examine if aquatic invertebrate data of increased taxonomical resolution but expressed on a binary abundance (frequent/rare) scale and referring to good bioindicator species only suffice to indicate clear gradients in water courses with high natural variability such as intermittent Mediterranean streams. Invertebrate samples were collected from 74 sites in the Quarteira River basin, located in southern Portugal. Their classification with the use of a Kohonen artificial neural network (i.e., self-organising map, SOM) resulted in five categories. The variables that drove this categorization were primarily altitude, temperature and conductivity, but also type of substrate, riparian cover and percentage of riffles present. According to the indicator species analysis (ISA), almost all the studied taxa were significantly associated with certain SOM categories except for the category that included sites with disrupted flow regime. The SOM and ISA allowed us to effectively recognize biotic and abiotic patterns. Combined application of both methods may thus greatly enhance the effectiveness and precision of biological surveillance and establish reference sites for specific channel units in streams with high natural variability such as intermittent Mediterranean streams. (C) 2016 Elsevier Ltd. All rights reserved.Foundation for Science and Technology (FCT) of Portugal [ERA-IWRM/0003/2009

Density/biomass variables presented directly to the Kohonen artificial neural network.

<p>Biomass of cyanobacteria (a-c), densities of <i>Daphnia longispina</i> (d-f) and <i>Leptodora kindtii</i> (g-i) at the Zarzęcin (a, d, g), Bronisławów (b, e, h) and Tresta (c, f, i) stations. Explanations are the same as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144109#pone.0144109.g007" target="_blank">Fig 7</a>.</p