3,669 research outputs found
A Review of the Main Machine Learning Methods for Predicting Residential Energy Consumption
The ability to predict future energy consumption is very important for energy distribution companies because it allows them to estimate energy needs and supply them accordingly. Consumption prediction makes it possible for those companies to optimize their processes by, for example, providing them with knowledge about future periods of high energy demand or by enabling them to adapt their tariffs to customer consumption. Machine Learning techniques allow to predict future energy consumption on the basis of the customers' historical consumption and several other parameters. This article reviews some of the main machine learning models capable of predicting energy consumption, in our case study we use a specific set of data extracted from a two-year-period of a shoe store. Among the evaluated methods, Gradient Boosting has obtained an 86.3% success rate in predicting consumption.This work was carried out under the frame of the "Towards Sustainable Intelligent Mobility: Blockchain-based framework for IoT Security" Ref. RTI2018-095390-B-C32" project. The project was supported and funded by the Spanish Ministerio de Economıa, Industria y Competitividad. Retos de investigacion, ´Proyectos I+D+i.info:eu-repo/semantics/publishedVersio
PACCE: Perl Algorithm to Compute Continuum and Equivalent Widths
We present Perl Algorithm to Compute continuum and Equivalent Widths (pacce).
We describe the methods used in the computations and the requirements for its
usage. We compare the measurements made with pacce and "manual" ones made using
iraf splot task. These tests show that for SSP models the equivalent widths
strengths are very similar (differences <0.2A) for both measurements. In real
stellar spectra, the correlation between both values is still very good, but
with differences of up to 0.5A. pacce is also able to determine mean continuum
and continuum at line center values, which are helpful in stellar population
studies. In addition, it is also able to compute the uncertainties in the
equivalent widths using photon statistics. The code is made available for the
community through the web at http://www.if.ufrgs.br/~riffel/software.html.Comment: 8 pages, 5 figures, accepted by Astrophysics and Space Scienc
Resolving galaxies in time and space: II: Uncertainties in the spectral synthesis of datacubes
In a companion paper we have presented many products derived from the
application of the spectral synthesis code STARLIGHT to datacubes from the
CALIFA survey, including 2D maps of stellar population properties and 1D
averages in the temporal and spatial dimensions. Here we evaluate the
uncertainties in these products. Uncertainties due to noise and spectral shape
calibration errors and to the synthesis method are investigated by means of a
suite of simulations based on 1638 CALIFA spectra for NGC 2916, with
perturbations amplitudes gauged in terms of the expected errors. A separate
study was conducted to assess uncertainties related to the choice of
evolutionary synthesis models. We compare results obtained with the Bruzual &
Charlot models, a preliminary update of them, and a combination of spectra
derived from the Granada and MILES models. About 100k CALIFA spectra are used
in this comparison.
Noise and shape-related errors at the level expected for CALIFA propagate to
0.10-0.15 dex uncertainties in stellar masses, mean ages and metallicities.
Uncertainties in A_V increase from 0.06 mag in the case of random noise to 0.16
mag for shape errors. Higher order products such as SFHs are more uncertain,
but still relatively stable. Due to the large number statistics of datacubes,
spatial averaging reduces uncertainties while preserving information on the
history and structure of stellar populations. Radial profiles of global
properties, as well as SFHs averaged over different regions are much more
stable than for individual spaxels. Uncertainties related to the choice of base
models are larger than those associated with data and method. Differences in
mean age, mass and metallicity are ~ 0.15 to 0.25 dex, and 0.1 mag in A_V.
Spectral residuals are ~ 1% on average, but with systematic features of up to
4%. The origin of these features is discussed. (Abridged)Comment: A&A, accepte
Investigation of the Anticancer and Drug Combination Potential of Brominated Coelenteramines toward Breast and Prostate Cancer
Cancer is a very challenging disease to treat, both in terms of therapeutic efficiency and harmful side effects, which continues to motivate the pursuit for novel molecules with potential anticancer activity. Herein, we have designed, synthesized, and evaluated the cytotoxicity of different brominated coelenteramines, which are metabolic products and synthesis precursors of the chemi-/bioluminescent system of marine coelenterazine. The evaluation of the anticancer potential of these molecules was carried out for both prostate and breast cancer, while also exploring their potential for use in combination therapy. Our results provided further insight into the structure-activity relationship of this type of molecule, such as their high structural specificity, as well highlighting the 4-bromophenyl moiety as essential for the anticancer activity. The obtained data also indicated that, despite their similarity, the anticancer activity displayed by both brominated coelenteramines and coelenterazines should arise from independent mechanisms of action. Finally, one of the studied coelenteramines was able to improve the profile of a known chemotherapeutic agent, even at concentrations in which its anticancer activity was not relevant. Thus, our work showed the potential of different components of marine chemi-/bioluminescent systems as novel anticancer molecules, while providing useful information for future optimizations
Target-Oriented Synthesis of Marine Coelenterazine Derivatives with Anticancer Activity by Applying the Heavy-Atom Effect
Photodynamic therapy (PDT) is an anticancer therapeutic modality with remarkable advantages over more conventional approaches. However, PDT is greatly limited by its dependence on external light sources. Given this, PDT would benefit from new systems capable of a light-free and intracellular photodynamic effect. Herein, we evaluated the heavy-atom effect as a strategy to provide anticancer activity to derivatives of coelenterazine, a chemiluminescent single-molecule widespread in marine organisms. Our results indicate that the use of the heavy-atom effect allows these molecules to generate readily available triplet states in a chemiluminescent reaction triggered by a cancer marker. Cytotoxicity assays in different cancer cell lines showed a heavy-atom-dependent anticancer activity, which increased in the substituent order of hydroxyl < chlorine < bromine. Furthermore, it was found that the magnitude of this anticancer activity is also dependent on the tumor type, being more relevant toward breast and prostate cancer. The compounds also showed moderate activity toward neuroblastoma, while showing limited activity toward colon cancer. In conclusion, the present results indicate that the application of the heavy-atom effect to marine coelenterazine could be a promising approach for the future development of new and optimized self-activating and tumor-selective sensitizers for light-free PDT
Galaxies in a Simulated CDM Universe II: Observable Properties and Constraints on Feedback
We compare the properties of galaxies that form in a cosmological simulation
without strong feedback to observations at z=0. We confirm previous findings
that models without strong feedback overproduce the observed galaxy baryonic
mass function, especially at the low and high mass extremes. Through
post-processing we investigate what kinds of feedback would be required to
reproduce observed galaxy masses and star formation rates. To mimic an extreme
form of "preventive" feedback (e.g., AGN radio mode) we remove all baryonic
mass that was originally accreted via "hot mode" from shock-heated gas. This
does not bring the high mass end of the galaxy mass function into agreement
with observations because much of the stellar mass in these systems formed at
high redshift from baryons that originally accreted via "cold mode" onto lower
mass progenitors. An efficient "ejective" feedback mechanism, such as supernova
driven winds, must reduce the masses of these progenitors. Feedback must also
reduce the masses of lower mass z=0 galaxies, which assemble at lower redshifts
and have much lower star formation rates. If we monotonically re-map galaxy
masses to reproduce the observed mass function, but retain the simulation's
predicted star formation rates, we obtain fairly good agreement with the
observed sequence of star-forming galaxies but fail to recover the observed
population of passive, low star formation rate galaxies. Suppressing all hot
mode accretion improves agreement for high mass galaxies but worsens the
agreement at intermediate masses. Reproducing these z=0 observations requires a
feedback mechanism that dramatically suppresses star formation in a fraction of
galaxies, increasing with mass, while leaving star formation rates of other
galaxies essentially unchanged.Comment: MNRAS in press. 15 pages, 5 figures, minimal changes from the first
versio
Incidence of chromosome numerical changes in multiple myeloma: fluorescence in situ hybridization analysis using 15 chromosome-specific probes
Fue el primer trabajo precursor de los estudios con FISH en pacientes con Mieloma mĂşltiple continuando la exitosa lĂnea de investigaciĂłn en mieloma del grupo de Salamanca, y por añadidura, del Grupo español de mieloma. La metodologĂa FISH es hoy en dĂa la principal herramienta de pronĂłstico en mieloma mĂşltiple en todo el mundo.[EN]The presence of complex karotypes with frequent numerical and structural abnormalities has been reported in 20 to 50% of multiple myeloma (MM) patients. This variability is mainly due to the difficulty of conventional cytogenetics to obtain tumor metaphases representative of all possible neoplastic clones in MM. To gain insight into the real incidence of numerical chromosome changes in MM we have studied by fluorescence in situ hybridization technique 15 different human chromosomes, 1, 3, 6, 7, 8, 9, 10, 11, 12, 13, 15, 17, 18, X, and Y, in a series of 52 MM patients. In all cases, the DNA index assessed by a propidium iodide/CD38 double-staining technique with flow cytometry was simultaneously investigated for correlation, with fluorescence in situ hybridization results. Additional aims of this study were 1) to analyze whether the abnormalities detected were common to all plasma cells or were present in only a subpopulation of tumor cells, 2) to explore changes caused by disease progression, and 3) to establish possible associations among the altered chromosomes. Although the overall incidence of numerical abnormalities was 67%, this frequency increased to 80% in the 41 cases in which 7 or more chromosomes were analyzed. Trisomies were significantly more common than monosomies (84% versus 16%). Chromosomes 9 and 15 were the most frequently altered (52% and 48% of cases, respectively), with all of their abnormalities corresponding to trisomies. The most frequent losses involved chromosomes 13 (26%) and X in females (32%). Other common numerical changes corresponded to chromosomes 1 (39%), 11 (37%), 6 (32%), 3 (31%), 18 (29%), 7 (28%), and 17 (22%). By contrast, chromosomes 8(13%), 10(8%), and 12(3%) were rarely altered. DNA aneuploidy by flow cytometry was detected in 67% of patients, and a high degree of correlation was observed between the DNA index obtained by flow cytometry and the chromosome index derived from fluorescence in situ hybridization studies, calculated according to two mathematical formulas (coefficient of correlation of 0.82 and 0.91 when at least 7 or 12 chromosomes were considered, respectively). The frequency of numeric chromosome aberrations was higher in those patients with progressive disease and, interestingly, trisomy of chromosome 8 was exclusively detected in this latter group of patients. Our study shows that, with the exception of chromosome 8, a possible marker of clonal evolution, the numeric chromosome changes are present in nearly all malignant plasma cells (r > 0.84). Finally, frequent associations between chromosomal aberrations were observed (ie, chromosomes 6, 7, 9, and 17; 7 and 15; and 11 and 17). By excluding them, it was found that two triple combinations of chromosome-specific probes, chromosomes 1 and 9 together with either chromosome 13 or 15, could be a useful marker for detection of residual disease, as it permits the identification of most MM patients displaying numerical changes.University Hosptial of Salamanca
Universidad de SalamancaHospital Universitario de Salamanc
Marine Toxins: Chemistry, Toxicity, Occurrence and Detection, with Special Reference to the Dutch Situation
Various species of algae can produce marine toxins under certain circumstances. These toxins can then accumulate in shellfish such as mussels, oysters and scallops. When these contaminated shellfish species are consumed severe intoxication can occur. The different types of syndromes that can occur after consumption of contaminated shellfish, the corresponding toxins and relevant legislation are discussed in this review. Amnesic Shellfish Poisoning (ASP), Paralytic Shellfish Poisoning (PSP), Diarrheic Shellfish Poisoning (DSP) and Azaspiracid Shellfish Poisoning (AZP) occur worldwide, Neurologic Shellfish Poisoning (NSP) is mainly limited to the USA and New Zealand while the toxins causing DSP and AZP occur most frequently in Europe. The latter two toxin groups are fat-soluble and can therefore also be classified as lipophilic marine toxins. A detailed overview of the official analytical methods used in the EU (mouse or rat bioassay) and the recently developed alternative methods for the lipophilic marine toxins is given. These alternative methods are based on functional assays, biochemical assays and chemical methods. From the literature it is clear that chemical methods offer the best potential to replace the animal tests that are still legislated worldwide. Finally, an overview is given of the situation of marine toxins in The Netherlands. The rat bioassay has been used for monitoring DSP and AZP toxins in The Netherlands since the 1970s. Nowadays, a combination of a chemical method and the rat bioassay is often used. In The Netherlands toxic events are mainly caused by DSP toxins, which have been found in Dutch shellfish for the first time in 1961, and have reoccurred at irregular intervals and in varying concentrations. From this review it is clear that considerable effort is being undertaken by various research groups to phase out the animal tests that are still used for the official routine monitoring programs
What determines satellite galaxy disruption?
In hierarchical structure formation, dark matter halos that merge with larger
halos can persist as subhalos. These subhalos are likely hosts of visible
galaxies. While the dense halo environment rapidly strips subhalos of their
dark mass, the compact luminous material can remain intact for some time,
making the correspondence of galaxies with severely stripped subhalos unclear.
Many galaxy evolution models assume that satellite galaxies eventually merge
with their central galaxy, but this ignores the possibility of satellite tidal
disruption. We use a high-resolution -body simulation of cosmological volume
to explore satellite galaxy merging/disruption criteria based on dark matter
subhalo dynamics. We explore the impact that satellite merging/disruption has
on the Halo Occupation Distribution and radial profile of the remnants. Using
abundance matching to assign stellar mass/luminosity to subhalos, we compare
with observed galaxy clustering, satellite fractions, cluster satellite
luminosity functions, finding that subhalos reproduce well these observables on
all scales. Our results imply that satellite subhalos corresponding to >0.2L*
galaxies must be well-resolved down to 1-3% of their mass at infall to robustly
trace the galaxy population. We also explore a simple analytic model based on
dynamical friction for satellite galaxy infall, finding good agreement with our
subhalo catalog and observations.Comment: 19 pages, 14 figures, accepted for publication in MNRA
- …