3,764 research outputs found
Nitric Oxide Regulates Neurogenesis in the Hippocampus following Seizures
Hippocampal neurogenesis is changed by brain injury. When neuroinflammation accompanies injury, activation of resident microglial cells promotes the release of inflammatory cytokines and reactive oxygen/nitrogen species like nitric oxide (NO). In these conditions, NO promotes proliferation of neural stem cells (NSC) in the hippocampus. However, little is known about the role of NO in the survival and differentiation of newborn cells in the injured dentate gyrus. Here we investigated the role of NO following seizures in the regulation of proliferation, migration, differentiation, and survival of NSC in the hippocampus using the kainic acid (KA) induced seizuremouse model. We show that NO increased the proliferation of NSC and the number of neuroblasts following seizures but was detrimental to the survival of newborn neurons. NO was also required for the maintenance of long-term neuroinflammation. Taken together, our data show that NO positively contributes to the initial stages of neurogenesis following seizures but compromises survival of newborn neurons.Foundation for Science and Technology (FCT, Portugal); COMPETE; FEDER [PTDC/SAU-NEU/102612/2008, PTDC/NEU-OSD/0473/2012, PEst-C/SAU/LA0001/2013-2014, PEst-OE/EQB/LA0023/2013-2014]; FCT, Portugal [SFRH/BPD/78901/2011, SFRH/BD/77903/2011
Acoustic channel frequency response estimation using sources of opportunity
This work addresses the usage of ship radiated noise to estimate the ocean acoustic water propagation channel response between two vertical line arrays. We derive an expression for the frequency response channel estimate using a normal mode development based on cross-correlation methods, in a similar way as Roux et al. [1]. Its applicability and limitations in simulated and real conditions is discussed. Simulations are conducted using the normal mode model KRAKEN, based on the experimental setup and environmental parameters gathered during the RADAR' 07 sea trial, off the west coast of Portugal, in July of 2007. In this sea trial two drifting vertical line arrays with 16 and 8 hydrophones were deployed in a range independent bathymetric area, at 300 m and 1.3 km distance from the Research Vessel NRP D. Carlos I, whose track then moved away from the arrays, radiating noise in the frequency band bellow 750 Hz. The wave fronts structure, obtained from actual acoustic data of the above referred sea trial, reveals agreement with the simulations obtained with the proposed approach. These results suggest the feasibility of the method for future application in a passive ocean acoustics tomography framework to the estimation of sound speed perturbations in the water column
Policy Effects on the Quality of Public Health Care: Evaluating Portuguese Public Hospitals’ Quality through Customers’ Views
In this paper, public health care administration issues are reviewed
and public hospital patients’ views on quality of health care are empirically
tested. The purpose is to support the recommendation of new public policies that
lead to better performance, if necessary. Hospital patients’ views on service quality were assessed through a questionnaire to estimate a global customer satisfaction measure. We argue that customer satisfaction should be measured through
multiple indicators, as a latent variable. Thus, we considered the latent segment
models (LSM) approach to assess customer service satisfaction. We found a two segment latent structure: segment 1, the satisfied, with 48 percent of patients,
mostly male and middle-aged patients; and segment 2, the unsatisfied, with 52
percent of patients, mostly female and youngest/oldest patients.info:eu-repo/semantics/publishedVersio
Los moluscos del cesped algal intermareale en Azores
The molluscan fauna of the high intertidal algal turf on the island of Pico (Azores) was
studied in order to complement existing descriptions of the intertidal biota on these islands. A total of 15,275 specimens belonging to 19 species were found. Five species, the gastropods Alvania mediolittoralis Gofas, 1989, Omalogyra atomus (Philippi, 1841), Pisinna glabrata (Megerle von Muhlfeld, 1824) and Skeneopsis planorbis (Fabricius 0., 1780), and the bivalve Lasaea adansoni (Gmelin, 1791), account for 98% of the total number of
specimens, P. glabrata itself being responsible for 46% of all specimens.
In places where patellid limpets are absent, Ihe algal turf extends higher in the intertidal zone. In such places, three very abundant molluscan species characterize molluscan assemblages in the algal turf: Lasaea adansoni, Skeneopsis planorbis and Pisinna glabrata, Lasaeo adansoni and Skeneopsis planorbis virtually disappear in the transition from algal lurf to algal fronds, the only (very) abundant species being P. glabrata and, with less importance, Omalogyra atomus and Sinezona cingulata (Costa O.G., 1861)
Close range ship noise cross correlations with a vector sensor in view of geoacoustic inversion
Distant ship noise has been utilized for geoacoustic inversion and ocean monitoring for many years. In a shallow water experiment, Makai 2005, a 4-element acoustic vector sensor array was deployed at the stern of the research vessel R/V Kilo Moana. The recorded engine noise of R/V Kilo Moana during its dynamic positioning was analyzed by the DEMON (Detection of Envelope Modulation on Noise) method. The strongest modulation frequency band of the ship noise was found by a group of band-pass filters for further data processing. Multipath arrivals in the vertical particle velocity have higher signal-to-noise ratios than those in the horizontal particle velocities because of steep arrival directions. By exploiting this advantage, the cross-correlation of broadband ship noise between the pressure and the vertical particle velocity can be used for multipath information exploration. Since ship noise is often characterized as continuous broadband noise plus strong tonal noise, the cross-correlation of tonal noise would dominate that of broadband noise, and consequently cover the multipath arrival pattern. Therefore, spectral weighting functions are applied in order to reduce the noise contamination and ensure sharp multipath peaks in the cross-correlation. For engine noise emitted by the dynamically positioned ship, a short correlation time of 0.4s was used in order to keep the time delay fluctuation details of multipath arrivals. Clear multiple arrivals are seen in the cross-correlation of different arrivals, and verified by the ray tracing program TRACEO. The results demonstrate the potential of only one acoustic vector sensor in applications of source localization and geoacoustic inversion
The Globular Cluster System of the Coma cD Galaxy NGC 4874 from Hubble Space Telescope ACS and WFC3/IR Imaging
We present new HST optical and near-infrared (NIR) photometry of the rich
globular cluster (GC) system of NGC 4874, the cD galaxy in the core of the Coma
cluster (Abell 1656). NGC 4874 was observed with the HST Advanced Camera for
Surveys in the F475W (g) and F814W (I) passbands and the Wide Field Camera 3 IR
Channel in F160W (H). The GCs in this field exhibit a bimodal optical color
distribution with more than half of the GCs falling on the red side at g-I > 1.
Bimodality is also present, though less conspicuously, in the optical-NIR I-H
color. Consistent with past work, we find evidence for nonlinearity in the g-I
versus I-H color-color relation. Our results thus underscore the need for
understanding the detailed form of the color-metallicity relations in
interpreting observational data on GC bimodality. We also find a very strong
color-magnitude trend, or "blue tilt," for the blue component of the optical
color distribution of the NGC 4874 GC system. A similarly strong trend is
present for the overall mean I-H color as a function of magnitude; for M_814 <
-10 mag, these trends imply a steep mass-metallicity scaling with , but the scaling is not a simple power law and becomes
much weaker at lower masses. As in other similar systems, the spatial
distribution of the blue GCs is more extended than that of the red GCs, partly
because of blue GCs associated with surrounding cluster galaxies. In addition,
the center of the GC system is displaced by 4+/-1 kpc towards the southwest
from the luminosity center of NGC 4874, in the direction of NGC 4872. Finally,
we remark on a dwarf elliptical galaxy with a noticeably asymmetrical GC
distribution. Interestingly, this dwarf has a velocity of nearly -3000 km/s
with respect to NGC 4874; we suggest it is on its first infall into the cluster
core and is undergoing stripping of its GC system by the cluster potential.Comment: 24 pages, 20 figures, accepted for publication in Ap
Pretreatments applied to microalgae residues to enhance anaerobic digestion
ABSTRACT: Biomass of microalga Chlorella protothecoides, grown under autotrophic and heterotrophic
conditions and subjected to pretreatments, were energetically valorized through anaerobic digestion process according to the substrates: autotrophic algae (A), heterotrophic algae (H), heterotrophic algae extracted (HE), autoclave pretreated heterotrophic algae (HPA), enzyme pretreated heterotrophic algae (HPE), ultrasound pretreated heterotrophic algae (HPU), and inoculum (I). Despite the application of pretreatments, the highest methane production was obtained in the algae extracted digestion with 172 mL CH4, against 153, 126 and 142 mL obtained in HPA, HPE and HPU, respectively. The COD removal capacity was higher in the HPA sample while the TS and VS removal reached higher values in the autotrophic alga.N/
The new centrality of water and sanitation post COVID-19
COVID-19, known for severe acute respiratory syndrome caused by coronavírus SARS-Cov-2 is
characterized by its rapid spread. The pandemic culminated in a social isolation creating
significant impacts on the economy and it has taken attention to the key aspects of water,
sanitation and hygiene and the identification of the coronavírus presence in wastewater. The
purpose of this article is to explain some of the aspects associated with the centrality of the
water and sanitation binomial that may prove to be decisive for recovering the world economy
in the post COVID-19 period, through the presentation and evaluation of statistics and scientific
studies, namely:: 1) human right to water and sanitation, for guarantee life quality, productive
capacity and public health, but with a challenge, especially for economically vulnerable
countries; 2) relationship with the epidemiology and occurrence of the coronavírus in the
sewage, drawing the attention of the scientific community, society and decision makers, even
though there is still no scientific evidence of its fecal-oral transmission; 3) the relationship
between water and the economy, considering it a basic resource for industrial and agricultural
production and job creation. The construction of the concept ?new centrality of water and
sanitation? can be considered as a key factor for the economy recovery post-COVID-19.A COVID-19, conhecida por síndrome respiratória aguda grave, causada pelo coronavírus SARS-CoV-2, por ser de rápida propagação, culminou no estabelecimento do isolamento social, causando impactos significativos à economia. Assim, a pandemia da COVID-19 tem chamado a atenção para o tema água e saneamento em aspectos relacionados à essencialidade do seu provimento, à medida preventiva de higienização das mãos e à identificação da presença do coronavírus no esgoto sanitário. O objetivo do presente artigo é, por meio da apresentação e avaliação de estatísticas e estudos científicos, explicitar alguns dos aspectos associados à centralidade do binômio água e saneamento que podem revelar-se determinantes para o relançamento da economia mundial no período pós-COVID-19, nomeadamente: 1) direito humano à água e ao saneamento, fundamentais para a garantia da qualidade de vida, da capacidade produtiva e da saúde pública, porém com uma realidade ainda desafiadora especialmente para países economicamente vulneráveis; 2) relação com a epidemiologia e ocorrência do coronavírus no esgoto sanitário, chamando a atenção da comunidade científica, da sociedade e dos tomadores de decisão, mesmo que ainda sem evidências científicas da sua transmissão feco-oral; 3) relação da água com a economia, considerando-a recurso base para produção industrial e agrícola e geração de empregos. Conclui-se assim pela construção do conceito “nova centralidade da água e do saneamento” como fator chave para a retomada da economia pós-COVID-1
Natural origin scaffolds with in situ pore forming capability for bone tissue engineering applications
This work describes the development of a biodegradable matrix, based on chitosan and starch, with the ability to form a porous structure
in situ due to the attack by specific enzymes present in the human body (a-amylase and lysozyme). Scaffolds with three different
compositions were developed: chitosan (C100) and chitosan/starch (CS80-20, CS60-40). Compressive test results showed that these materials
exhibit very promising mechanical properties, namely a high modulus in both the dry and wet states. The compressive modulus in
the dry state for C100 was 580 ± 33 MPa, CS80-20 (402 ± 62 MPa) and CS60-40 (337 ± 78 MPa). Degradation studies were performed
using a-amylase and/or lysozyme at concentrations similar to those found in human serum, at 37 C for up to 90 days. Scanning electron
micrographs showed that enzymatic degradation caused a porous structure to be formed, indicating the potential of this methodology to
obtain in situ forming scaffolds. In order to evaluate the biocompatibility of the scaffolds, extracts and direct contact tests were performed.
Results with the MTT test showed that the extracts of the materials were clearly non-toxic to L929 fibroblast cells. Analysis
of cell adhesion and morphology of seeded osteoblastic-like cells in direct contact tests showed that at day 7 the number of cells on
CS80-20 and CS60-40 was noticeably higher than that on C100, which suggests that starch containing materials may promote cell adhesion
and proliferation. This combination of properties seems to be a very promising approach to obtain scaffolds with gradual in vivo
pore forming capability for bone tissue engineering applications.This work was supported by the European NoE EXPERTISSUES (NMP3-CT-2004-500283), the European STREP HIPPOCRATES (NMP3-CT-2003-505758) and the Portuguese Foundation for Science and Technology (FCT) through POCTI and/or FEDER programmes
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