506 research outputs found
Evaluación y monitorización de la durabilidad de las cubiertas del Hipódromo de la Zarzuela de Madrid
Optimal farm design with parabolic shape photovoltaic panels using multi-objective optimization
To acquire the maximum efficiency for solar electricity conversion, a solar panel has to absorb nearly every single photon of light emitted from the sun. The shape of the solar panel itself plays an important role in achieving this goal. Several studies have been conducted for different solar panel designs regardless of change in their internal or external shapes. In the first part of this thesis, a survey of solar photovoltaic (PV) panel shapes together with the advantages and disadvantages of the shapes is presented. The second part deals with using parabolic trough PV panels to obtain an optimal field design with two objectives, namely, maximum incident energy and minimum of the deployment cost. This design involves the relationships between the field and collector decision parameters and solar radiation data.To acquire the maximum efficiency for solar electricity conversion, a solar panel has to absorb nearly every single photon of light emitted from the sun. The shape of the solar panel itself plays an important role in achieving this goal. Several studies have been conducted for different solar panel designs regardless of change in their internal or external shapes. In the first part of this thesis, a survey of solar photovoltaic (PV) panel shapes together with the advantages and disadvantages of the shapes is presented. The second part deals with using parabolic trough PV panels to obtain an optimal field design with two objectives, namely, maximum incident energy and minimum of the deployment cost. This design involves the relationships between the field and collector decision parameters and solar radiation data
Multimodality in galaxy clusters from SDSS DR8: substructure and velocity distribution
We search for the presence of substructure, a non-Gaussian, asymmetrical
velocity distribution of galaxies, and large peculiar velocities of the main
galaxies in galaxy clusters with at least 50 member galaxies, drawn from the
SDSS DR8. We employ a number of 3D, 2D, and 1D tests to analyse the
distribution of galaxies in clusters: 3D normal mixture modelling, the
Dressler-Shectman test, the Anderson-Darling and Shapiro-Wilk tests and others.
We find the peculiar velocities of the main galaxies, and use principal
component analysis to characterise our results. More than 80% of the clusters
in our sample have substructure according to 3D normal mixture modelling, the
Dressler-Shectman (DS) test shows substructure in about 70% of the clusters.
The median value of the peculiar velocities of the main galaxies in clusters is
206 km/s (41% of the rms velocity). The velocities of galaxies in more than 20%
of the clusters show significant non-Gaussianity. While multidimensional normal
mixture modelling is more sensitive than the DS test in resolving substructure
in the sky distribution of cluster galaxies, the DS test determines better
substructure expressed as tails in the velocity distribution of galaxies.
Richer, larger, and more luminous clusters have larger amount of substructure
and larger (compared to the rms velocity) peculiar velocities of the main
galaxies. Principal component analysis of both the substructure indicators and
the physical parameters of clusters shows that galaxy clusters are complicated
objects, the properties of which cannot be explained with a small number of
parameters or delimited by one single test. The presence of substructure, the
non-Gaussian velocity distributions, as well as the large peculiar velocities
of the main galaxies, shows that most of the clusters in our sample are
dynamically young.Comment: 15 pages, 11 figures, 2 online tables, accepted for publication in
Astronomy and Astrophysic
Multimodality of rich clusters from the SDSS DR8 within the supercluster-void network
We study the relations between the multimodality of galaxy clusters drawn
from the SDSS DR8 and the environment where they reside. As cluster environment
we consider the global luminosity density field, supercluster membership, and
supercluster morphology. We use 3D normal mixture modelling, the
Dressler-Shectman test, and the peculiar velocity of cluster main galaxies as
signatures of multimodality of clusters. We calculate the luminosity density
field to study the environmental densities around clusters, and to find
superclusters where clusters reside. We determine the morphology of
superclusters with the Minkowski functionals and compare the properties of
clusters in superclusters of different morphology. We apply principal component
analysis to study the relations between the multimodality parametres of
clusters and their environment simultaneously. We find that multimodal clusters
reside in higher density environment than unimodal clusters. Clusters in
superclusters have higher probability to have substructure than isolated
clusters. The superclusters can be divided into two main morphological types,
spiders and filaments. Clusters in superclusters of spider morphology have
higher probabilities to have substructure and larger peculiar velocities of
their main galaxies than clusters in superclusters of filament morphology. The
most luminous clusters are located in the high-density cores of rich
superclusters. Five of seven most luminous clusters, and five of seven most
multimodal clusters reside in spider-type superclusters; four of seven most
unimodal clusters reside in filament-type superclusters. Our study shows the
importance of the role of superclusters as high density environment which
affects the properties of galaxy systems in them.Comment: 16 pages, 12 figures, 2 online tables, accepted for publication in
Astronomy and Astrophysic
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Feasibility and impact of Creciendo Sanos, a clinic-based pilot intervention to prevent obesity among preschool children in Mexico City
Background: Mexico has the highest adult overweight and obesity prevalence in the Americas; 23.8% of children <5 years old are at risk for overweight and 9.7% are already overweight or obese. Creciendo Sanos was a pilot intervention to prevent obesity among preschoolers in Instituto Mexicano del Seguro Social (IMSS) clinics. Methods: We randomized 4 IMSS primary care clinics to either 6 weekly educational sessions promoting healthful nutrition and physical activity or usual care. We recruited 306 parent-child pairs: 168 intervention, 138 usual care. Children were 2-5 years old with WHO body mass index (BMI) z-score 0-3. We measured children’s height and weight and parents reported children’s diet and physical activity at baseline and 3 and 6-month follow-up. We analyzed behavioral and BMI outcomes with generalized mixed models incorporating multiple imputation for missing values. Results: 93 (55%) intervention and 96 (70%) usual care families completed 3 and 6-month follow-up. At 3 months, intervention v. usual care children increased vegetables by 6.3 servings/week (95% CI, 1.8, 10.8). In stratified analyses, intervention participants with high program adherence (5-6 sessions) decreased snacks and screen time and increased vegetables v. usual care. No further effects on behavioral outcomes or BMI were observed. Transportation time and expenses were barriers to adherence. 90% of parents who completed the post-intervention survey were satisfied with the program. Conclusions: Although satisfaction was high among participants, barriers to participation and retention included transportation cost and time. In intention to treat analyses, we found intervention effects on vegetable intake, but not other behaviors or BMI. Trial registration ClinicalTrials.gov NCT01539070. Comisión Nacional de Investigación Científica del IMSS: 2009-785-120
Optimization of Ti/Ta2O5–SnO2 electrodes and reaction parameters for electrocatalytic oxidation of methylene blue
Impact of regulated and emerging pollutants and microplastics in marine ecosystems (IMPACTA project)
Marine ecosystems are nowadays subjected to a massive input of synthetic chemicals from everywhere. Unfortunately only a small portion of them is being monitored, and it is necessary to identify which pollutants can produce adverse impacts in the marine environment. IMPACTA project (CTM2013-48194-C3) is characterizing the distribution of regulated and emerging contaminants and microplastics in marine sediments, and evaluating the biological effects that they can cause (sing sublethal embryotoxicity tests, endocrine disruption and biomarkers). Sensitive and selective analytical methods are being developed and validated for pharmaceuticals, perfluorinated compounds, organophosphorus pesticides, triazines, personal care products, nonylphenols and alkylated PAHs in sediments. Thus, relevant pollutants present in coastal and offshore areas will be identified. Furthermore potential toxic effects of the contaminants present in coastal sediments are being assessed through embryotoxicity bioassays and also the biological effects on different marine species as a consequence of their exposition to specific compounds.
Another relevant contribution of this project will be the assessment of the impact of micro-plastics, first time in the Spanish coastal areas. Their potential toxic effects and their role in the transference of pollutants in the marine environment are being assessed. The concentration and composition of microplastics in sediments and demersal fish stomachs are being characterized, and their potential biological effects on marine invertebrates are also being investigated
First observations of oblique ionospheric sounding chirp signal in Mexico
The results of the first experiment of oblique ionospheric sounding (OIS) chirp signal reception in Mexico are
reported. Maximal and Lowest Observed Frequencies variations were studied under the quiet Space Weather
conditions. The diurnal ionospheric variations by OIS signal confirm the results based on GNSS data in the
Mexican region. The best HF radio propagation conditions along the considered path are during morning and
daytime hours. The multi-hop propagation is frequent. The interlayer propagation modes are present at nighttime
Restoring cellular magnesium balance through Cyclin M4 protects against acetaminophen-induced liver damage
Acetaminophen overdose is one of the leading causes of acute liver failure and liver transplantation in the Western world. Magnesium is essential in several cellular processess. The Cyclin M family is involved in magnesium transport across cell membranes. Herein, we identify that among all magnesium transporters, only Cyclin M4 expression is upregulated in the liver of patients with acetaminophen overdose, with disturbances in magnesium serum levels. In the liver, acetaminophen interferes with the mitochondrial magnesium reservoir via Cyclin M4, affecting ATP production and reactive oxygen species generation, further boosting endoplasmic reticulum stress. Importantly, Cyclin M4 mutant T495I, which impairs magnesium flux, shows no effect. Finally, an accumulation of Cyclin M4 in endoplasmic reticulum is shown under hepatoxicity. Based on our studies in mice, silencing hepatic Cyclin M4 within the window of 6 to 24 h following acetaminophen overdose ingestion may represent a therapeutic target for acetaminophen overdose induced liver injury
A survey of zoonotic pathogens carried by house mouse and black rat populations in Yucatan, Mexico
The house mouse (Mus musculus) and the black rat (Rattus rattus) are reservoir hosts for zoonotic pathogens, several of which cause neglected tropical diseases (NTDs). Studies of the prevalence of these NTD-causing zoonotic pathogens, in house mice and black rats from tropical residential areas are scarce. Three hundred and two house mice and 161 black rats were trapped in 2013 from two urban neighbourhoods and a rural village in Yucatan, Mexico, and subsequently tested for Trypanosoma cruzi, Hymenolepis diminuta and Leptospira interrogans. Using the polymerase chain reaction we detected T. cruzi DNA in the hearts of 4.9% (8/165) and 6.2% (7/113) of house mice and black rats, respectively. We applied the sedimentation technique to detect eggs of H. diminuta in 0.5% (1/182) and 14.2% (15/106) of house mice and black rats, respectively. Through the immunofluorescent imprint method, L. interrogans was identified in 0.9% (1/106) of rat kidney impressions. Our results suggest that the black rat could be an important reservoir for T. cruzi and H. diminuta in the studied sites. Further studies examining seasonal and geographical patterns could increase our knowledge on the epidemiology of these pathogens in Mexico and the risk to public health posed by rodents.Centro de Estudios Parasitológicos y de Vectore
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