1,520 research outputs found
Estimation of missing prices in real-estate market agent-based simulations with machine learning and dimensionality reduction methods
The opacity of real-estate market involves some challenges in their agent-based simulation. While some real-estate Web sites provide the prices of a great amount of houses publicly, the prices of the rest are not available. The estimation of these prices is necessary for simulating their evolution from a complete initial set of houses. Additionally, this estimation could also be useful for other purposes such as appraising houses, letting buyers know which are the best offered prices (i.e., the lowest ones compared to the appraisals) and recommending the buyers to set an initial price. This work proposes combining dimensionality reduction methods with machine learning techniques to obtain the estimated prices. In particular, this work analyzes the use of nonnegative factorization, recursive feature elimination and feature selection with a variance threshold, as dimensionality reduction methods. It compares the application of linear regression, support vector regression, the k-nearest neighbors and a multilayer perceptron neural network, as machine learning techniques. This work has applied a tenfold cross-validation for comparing the estimations and errors and assessing the improvement over a basic estimator commonly used in the beginning of simulations. The developed software and the used dataset are freely available from a data research repository for the sake of reproducibility and the support to other researchers
Uncertainty Analysis in the Inverse of Equivalent Conductance Method for Dealing with Crosstalk in 2-D Resistive Sensor Arrays
2-D resistive sensor arrays (RSAs) appear in many applications to measure physical quantities in a surface. However, they suffer from a crosstalk problem when the simplest configuration is used to address a row-column. Thus, the value of a single cell cannot be measured directly. Several hardware solutions have been proposed to solve it totally or partially but all of them make the circuit more complex. In a previous paper we proposed an innovative numerical solution to eliminate crosstalk after a complete scan of the matrix, which is named in this paper as Inverse of Equivalent Conductance Method (IECM). In the current study, we have analyzed the implications of the method for the uncertainty of the calculated cell resistance by first deriving the sensitivity of the solution and then applying uncertainty propagation theory. The theoretical results have been tested in simulated arrays and in a real 6x6 RSA with known values of resistances with good agreement. The uncertainty analysis is able to predict which values are reliable. In general, the lowest resistances of the array are better solved by IECM as expected. In addition, it is also shown that IECM has the potential to be adapted to other hardware configurations that reduce crosstalk, helping to overcome some of its limitations. IEE
Modern viticulture in southern Europe: Vulnerabilities and strategies for adaptation to water scarcity
Water
is
now
considered
the
most
important
but
vulnerable
resource
in
the
Mediterranean
region.
Nev
ertheless,
irrigation
expanded
fast
in
the
region
(e.g.
South
Portugal
and
Spain)
to
mitigate
environmental
stress
and
to
guarantee
stable
grape
yield
and
quality.
Sustainable
wine
production
depends
on
sustain
able
water
use
in
the
wine’s
supply
chain,
from
the
vine
to
the
bottle.
Better
understanding
of
grapevine
stress
physiology
(e.g.
water
relations,
temperature
regulation,
water
use
efficiency),
more
robust
crop
monitoring/phenotyping
and
implementation
of
best
water
management
practices
will
help
to
mitigate
climate
effects
and
will
enable
significant
water
savings
in
the
vineyard
and
winery.
In
this
paper,
we
focused
on
the
major
vulnerabilities
and
opportunities
of
South
European
Mediterranean
viticulture
(e.g.
in
Portugal
and
Spain)
and
present
a
multi-level
strategy
(from
plant
to
the
consumer)
to
overcome
region’s
weaknesses
and
support
strategies
for
adaptation
to
water
scarcity,
promote
sustainable
water
use
and
minimize
the
environmental
impact
of
the
sector
What's in your next-generation sequence data? An exploration of unmapped DNA and RNA sequence reads from the bovine reference individual.
BackgroundNext-generation sequencing projects commonly commence by aligning reads to a reference genome assembly. While improvements in alignment algorithms and computational hardware have greatly enhanced the efficiency and accuracy of alignments, a significant percentage of reads often remain unmapped.ResultsWe generated de novo assemblies of unmapped reads from the DNA and RNA sequencing of the Bos taurus reference individual and identified the closest matching sequence to each contig by alignment to the NCBI non-redundant nucleotide database using BLAST. As expected, many of these contigs represent vertebrate sequence that is absent, incomplete, or misassembled in the UMD3.1 reference assembly. However, numerous additional contigs represent invertebrate species. Most prominent were several species of Spirurid nematodes and a blood-borne parasite, Babesia bigemina. These species are either not present in the US or are not known to infect taurine cattle and the reference animal appears to have been host to unsequenced sister species.ConclusionsWe demonstrate the importance of exploring unmapped reads to ascertain sequences that are either absent or misassembled in the reference assembly and for detecting sequences indicative of parasitic or commensal organisms
A Roadmap for the Restoration of Mediterranean Macroalgal Forests
Canopy-forming macroalgae play a crucial role in coastal primary production and nutrient cycling, providing food, shelter, nurseries, and habitat for many vertebrate and invertebrate species. However, macroalgal forests are in decline in various places and natural recovery is almost impossible when populations become locally extinct. Hence, active restoration emerges as the most promising strategy to rebuild disappeared forests. In this regard, significant efforts have been made by several EU institutions to research new restoration tools for shallow and mesophotic reef habitats (e.g., MERCES EU project, AFRIMED, and ROCPOP-life) and effective techniques have subsequently been proposed to promote self-sustaining populations. Recent research indicates that macroalgal forest recovery requires a broad spectrum of measures, ranging from mitigating human impacts to restoring the most degraded populations and habitats, and that the viability of large restoration actions is compromised by ongoing human pressures (e.g., pollution, overgrazing, and climate change). We propose a roadmap for Mediterranean macroalgal restoration to assist researchers and stakeholders in decision-making, considering the most effective methods in terms of cost and cost-effectiveness, and taking background environmental conditions and potential threats into account. Last, the challenges currently faced by the restoration of rocky coastal ecosystems under changing climate conditions are also discussed
Amino-acid sequence and three-dimensional structure of the Staphylococcus aureus metalloproteinase at 1.72 å resolution
AbstractBackground: Aureolysin is an extracellular zinc-dependent metalloproteinase from the pathogenic bacterium Staphylococcus aureus. This enzyme exhibits in vitro activity against several molecules of biological significance for the host, indicating that it is involved in the pathology of staphylococcal diseases.Results: Here we report the amino-acid sequence and inhibitor-free X-ray crystal structure of aureolysin, a member of the thermolysin family of zinc-dependent metalloproteinases. This enzyme, which binds one zinc and three calcium ions, comprises a single chain of 301 amino acids that consists of a β-strand-rich upper domain and an α-helix-rich lower domain.Conclusions: The overall structure of aureolysin is very similar to that of the other three members of this family whose structures are known – thermolysin (TLN) from Bacillus thermoproteolyticus, neutral protease (NP) from Bacillus cereus and elastase (PAE) from Pseudomonas aeruginosa. But an important difference has been encountered: in contrast to what has been observed in the other three members of this family (TLN, NP and PAE), inhibitor-free aureolysin displays a ‘closed’ active site cleft conformation. This new structure therefore raises questions about the universality of the hinge-bending motion model for the neutral metalloproteinases
Carbon dioxide enrichment: a technique to mitigate the negative effects of salinity on the productivity of high value tomatoes
The present study was conducted to determine the mitigating influence of greenhouse CO2 enrichment on the negative effects of salinity in Mediterranean conditions. Hybrid Raf (cv. Delizia) tomato plants were exposed to two salinity levels of the nutrient solution (5 and 7 dS/m) obtained by adding NaCl, and two CO2 concentrations (350 and 800 μmol/mol) in which CO2 enrichment was applied during the daytime according to a strategy linked to ventilation. Increasing water salinity negatively affected the leaf area index (LAI), the specific leaf area (SLA), the water use efficiency (WUE), the radiation use efficiency (RUE) and dry weight (DW) accumulation resulting in lower marketable yield. The high salinity treatment (7 dS/m) increased fruit firmness (N), total soluble solids content (SSC) and titratable acidity (TA), whereas pH was reduced in the three ripening stages: mature green/breaker (G), turning (T), and pink/light red (P). Also, the increase in electrical conductivity of the nutrient solution led to a general change in intensity of the sensory characteristics of tomato fruits. On the other hand, CO2 enrichment did not affect LAI although SLA was reduced. RUE and DW accumulation were increased resulting in higher marketable yield, through positive effects on fruit number and their average weight. WUE was enhanced by CO2 supply mainly through increased growth and yield. Physical-chemical quality parameters such as fruit firmness, TA and pH were not affected by CO2 enrichment whereas SSC was enhanced. Greenhouse CO2 enrichment did mitigate the negative effect of saline conditions on productivity without compromising organoleptic and sensory fruit quality
Enseñar a gestionar la innovación en el máster
One of the most important skills of a university master oriented to the research is innovation and one important aspect is how to manage it. For replaying to the needs demanded by the Society through the research and development programmes, technical personnel able to carry out such projects and manage it are needed. Universities have launched different programmes of teaching for covering such needs of technical knowledge but as well it is important to prepare the students to manage the research. In this paper, the experience of the authors of two years teaching the subject “Management of electronics research projects under quality criteria” in the Master of Electronics Engineering is presented with the aim of improving this skill in the students by the knowledge and practice of management processes of electronics projects of research, development and innovation.Una de las competencias importantes de un máster universitario de introducción a la investigación es la innovación y un aspecto importante es cómo gestionarla. Para responder a las necesidades que la Sociedad demanda a través de los diversos programas de investigación y desarrollo que las distintas empresas lanzan, hace falta personal técnico capaz de llevar a cabo dichos proyectos y de gestionarlos bien. Las universidades han lanzado diversos programas de enseñanza para cubrir estas necesidades de conocimientos técnicos pero hace falta también dotar a los investigadores de formación adecuada en su gestión. En este artículo se presenta la experiencia de los autores tras dos años impartiendo la asignatura optativa “Gestión de proyectos de investigación electrónicos bajo criterios de calidad” en el Máster de Ingeniería Electrónica, con el objetivo de fomentar esta habilidad en los alumnos mediante el conocimiento y la práctica del proceso de gestión de los proyectos electrónicos de investigación, desarrollo e innovación tecnológica
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