350 research outputs found
An approach to the spatial distribution of fishing effort in the Gulf of Cadiz.
The spatial distribution of the fishing effort exerted
by the trawl fleet of Isla Cristina port (Huelva, Spain)
is simulated by means of an application (FAST) for
Geographic Information Systems (ArcView), which
can offer results just with limited input data.
The simulation were carried out with three input
variables: depth, distance from fishing grounds to port
and the fishing laws in force in the area. The results
obtained from two simulations tested match up the
effort distribution detected in the area for both the fleet
as a whole and a given segment of the same.Postprin
Discrete-event simulation to reduce waiting time in accident and emergency departments: a case study in a district general clinic
Waiting time is a crucial performance metric in A&E departments. In this regard, longer waiting times are related to low patient satisfaction, high mortality rates and more severe physical health complications. To analyze patient flow in these departments, discrete-event simulation (DES) has been used; however, its application has not been extended to evaluate the impact of improvement strategies. Therefore, this paper aims to design and pretest operational strategies for better ED care delivery using DES. First, input data analysis is carried out. Afterward, the DES model is developed and validated to establish whether it is statistically comparable with the real-world. Then, performance indicators of the current system are computed and analyzed. Finally, improvement strategies are proposed and evaluated by simulation modelling and statistical tests. A case study of an A&E department from a district general clinic is presented to validate the proposed framework. In particular, we will validate the effectiveness of introducing a triage system (Scenario 3), a strategy that is not currently adopted by the clinic. Results demonstrate that waiting times could be meaningfully diminished based on the proposed approaches within this paper
Evolución de los deltas submarinos de los ríos Guadalfeo y Adra en respuesta a las variaciones de los aportes sedimentarios
The Guadalfeo and the Adra submarine deltas off the northern coast of the Alboran Sea
have been built up under the direct influence of short and mountainous rivers. The area is subjected
to strong climatic seasonality, with sporadic winter torrential floods and high summer aridity. In
addition numerous anthropogenic activities have affected these systems, mostly during the last two
centuries. In order to decode the influence of climatic variability and anthropogenic impacts on
sediment supplies during the recent past, five sediment cores were collected from the Guadalfeo
and Adra submarine deltas. Benthic foraminiferal and sedimentological analyses, combined with
radiocarbon dating, were performed. The impact of torrential floods alternating with periods of low
rainfall or dry periods were recorded in the Adra and Guadalfeo prodeltas. Periods with low
abundance of benthic foraminifera and high amounts of coarse-grained sediments, were interpreted
as the result of enhanced sediment supply to the shelf triggered by major flood events. On the other
hand, periods with high amounts of fine-grained sediments and high abundances of colonizers and
opportunistic foraminiferal species indicate the establishment of new environments with distinct
ecological constraints. These environments were driven by lower sediment supplies during low
rainfall or dry periods. The most recent sedimentation seems to reflect the human interventions in
the rivers basins, such as deviation of the main river courses and dams construction, which reduced
the sediment input and promoted the deposition of shallow-water submarine deltas.Versión del edito
The evolution of the Guadalfeo submarine delta (northern Alboran Sea) during the last ca. 200 years
The Guadalfeo submarine delta is located on the northern Alboran Sea shelf in the western Mediterranean Sea. The sedimentary dynamics of the deltaic system is governed by the discharge of one of the major rivers in this area draining the western sector of the near-coastal Sierra Nevada Mountains. The area is under the influence of a Mediterranean climate, with high spatial and temporal (i.e., inter- and intra-annual) rain variability. Major anthropogenic forcing affected the river system during the 1930’s, with the deviation of the main river channel 2.5 km to the west, to its present position. More recently, the construction of Béznar (1977-1985) and Rules (1993-2003) dams have also contributed to limit the amount of sediments exported to the deltaic system.
In order to understand the interaction between river discharges and the evolution of the submarine delta at different timescales, sediment cores were collected off the ancient (core 13) and present-day (cores12 and 15) river courses. A chronological framework was performed and combined with sedimentological and benthic foraminiferal analyses.
Radiocarbon dating of plant debris from the base of the cores indicates that the sedimentary record goes back 200 years. In core 13, the variations between coarse and fine fractions along the core and the upward increase of benthic foraminiferal population density, would indicate that deposition possibly occurred until the deviation of the main river course to its present position. In the lower part of core 12, the strong alternation between coarse and fine sediment textures and the variable amounts of benthic foraminiferal species are interpreted as the result of an active fluvial regime. The upper part, with high percentages of fine sediments and high values of population density, could be attributed to the stabilization of the river course in its present-day location. Core 15, located at 11 m water depth, showed the highest content of gravel in the lower part of the core, high contents of silt at two core depths and increased percentages of sand to the top, indicating the strong influence of human interventions in the river basin and consequent changes in the sediment supply to the Guadalfeo submarine delta.info:eu-repo/semantics/publishedVersio
Multi-proxy evidence of rainfall variability recorded in subaqueous deltaic deposits off the Adra River, southeast Iberian Peninsula
The Adra River deltaic system, southeast Iberian Peninsula, shows a steep topography and is subjected to
strong climatic seasonality. This system has been affected by alternating wet and dry periods, and it has
also undergone numerous anthropogenic activities such as deforestation, mining activities, river channel
deviations and dam construction, particularly during the last two centuries. Two sediment cores were
retrieved off the Adra River, from the western (MS_V9) and eastern (MS_V4) lobes of the subaqueous
deltaic deposit. A multi-proxy study was carried out, including grain size, benthic foraminiferal assemblages,
magnetic susceptibility and geochemical element analyses, in order to understand the sedimentary
expression of recent climatic cycles and anthropogenic interventions in the river basin.
Periods of increased deposition of coarse-grained sediments, low absolute abundance of benthic
foraminifera and high elemental ratios indicative of terrigenous contributions, were interpreted as periods
of increased sediment supply to the shelf. Four flooding events were recorded in core MS_V9 and
three events on core MS_V4, of which two were observed in both cores. They were related to periods
with major floods that were documented on the southern Iberian Peninsula around 1770e1810 and 1860
e1870 AD. On the other hand, sediment core intervals exhibiting increasing proportion of fine-grained
sediments and higher abundances of foraminiferal species assigned as successful colonizers (Textularia
earlandi) and opportunistic species that feed on bacteria or terrestrial organic matter (Bolivina ordinaria,
Bulimina elongata, Eggerelloides scaber and Ammonia beccarii or tepida), indicate the establishment of new
environments with new ecological constraints. They were related to significant decreases of terrigenous
sediment input during low rainfall or dry periods. The increase of opportunistic species feeding on fresh
phytodetritus (Nonionella iridea, Nonionella stella, Nonionella sp., Brizalina dilatata, Epistominella vitrea
and Bolivinellina pseudopuntata), under more stable environmental conditions, also point to a stronger
marine influence on the prodeltaic environments during these periods. The human interventions on the
river basin after 1872 AD, with the deviation of the main river channel to the east, led to a drastic
reduction of the sediment exported to the western delta lobe. This study showed that the sedimentation
on the Adra subaqueous deltaic deposit was mainly controlled by rainfall variability from 1663 to 1872
AD, and afterwards by anthropogenic interventions.En prensa2,247
Reassessing the role of mitochondrial DNA mutations in autism spectrum disorder
<p>Abstract</p> <p>Background</p> <p>There is increasing evidence that impairment of mitochondrial energy metabolism plays an important role in the pathophysiology of autism spectrum disorders (ASD; OMIM number: 209850). A significant proportion of ASD cases display biochemical alterations suggestive of mitochondrial dysfunction and several studies have reported that mutations in the mitochondrial DNA (mtDNA) molecule could be involved in the disease phenotype.</p> <p>Methods</p> <p>We analysed a cohort of 148 patients with idiopathic ASD for a number of mutations proposed in the literature as pathogenic in ASD. We also carried out a case control association study for the most common European haplogroups (hgs) and their diagnostic single nucleotide polymorphisms (SNPs) by comparing cases with 753 healthy and ethnically matched controls.</p> <p>Results</p> <p>We did not find statistical support for an association between mtDNA mutations or polymorphisms and ASD.</p> <p>Conclusions</p> <p>Our results are compatible with the idea that mtDNA mutations are not a relevant cause of ASD and the frequent observation of concomitant mitochondrial dysfunction and ASD could be due to nuclear factors influencing mitochondrion functions or to a more complex interplay between the nucleus and the mitochondrion/mtDNA.</p
Factors associated with successful dietary changes in an energy-reduced Mediterranean diet intervention: a longitudinal analysis in the PREDIMED-Plus trial
Purpose
Long-term nutrition trials may fail to respond to their original hypotheses if participants do not comply with the intended dietary intervention. We aimed to identify baseline factors associated with successful dietary changes towards an energy-reduced Mediterranean diet (MedDiet) in the PREDIMED-Plus randomized trial.
Methods
Longitudinal analysis of 2985 participants (Spanish overweight/obese older adults with metabolic syndrome) randomized to the active intervention arm of the PREDIMED-Plus trial. Dietary changes were assessed with a 17-item energy-reduced MedDiet questionnaire after 6 and 12 months of follow-up. Successful compliance was defined as dietary changes from baseline of ≥ 5 points for participants with baseline scores < 13 points or any increase if baseline score was ≥ 13 points. We conducted crude and adjusted multivariable logistic regression models to identify baseline factors related to compliance.
Results
Consistent factors independently associated with successful dietary change at both 6 and 12 months were high baseline perceived self-efficacy in modifying diet (OR6-month: 1.51, 95% CI 1.25–1.83; OR12-month: 1.66, 95% CI 1.37–2.01), higher baseline fiber intake (OR6-month: 1.62, 95% CI 1.07–2.46; OR12-month: 1.62, 95% CI 1.07–2.45), having > 3 chronic conditions (OR6-month: 0.65, 95% CI 0.53–0.79; OR12-month: 0.76, 95% CI 0.62–0.93), and suffering depression (OR6-month: 0.80, 95% CI 0.64–0.99; OR12-month: 0.71, 95% CI 0.57–0.88).
Conclusion
Our results suggested that recruitment of individuals with high perceived self-efficacy to dietary change, and those who initially follow diets relatively richer in fiber may lead to greater changes in nutritional recommendations. Participants with multiple chronic conditions, specifically depression, should receive specific tailored interventions
Episodios de construcción de un delta mediterráneo: Cambio climático y modificaciones antropogénicas en el delta del río Adra
The evolutionary stages of the submarine delta off the Adra River are investigated in this
study, under the context of climatic fluctuations entangled with increasing human activities and
interventions in the drainage basins and adjacent shores during the Middle to Late Holocene. To
achieve that goal, we used an extensive database comprising a set of bathymetric data covering
different time slices, a dense grid of high-resolution seismic data and several sediment cores
collected in the two submarine lobes of the Adra River delta. Two main evolutionary phases can be
identified. The first one extended through most of the construction history and was mediated by
major climatic events at the Mediterranean scale; this phase included three major progradational
events occurring during the Mid Holocene, the Roman time and the Little Ice Age. The most recent
phase is strongly determined by human modifications of the fluvial channels, and resulted in a
drastic transformation of the submarine sedimentary environment.Versión del edito
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