We introduce Deep-HiTS, a rotation-invariant convolutional neural network (CNN) model for classifying images of transient candidates into artifacts or real sources for the High cadence Transient ...Survey (HiTS). CNNs have the advantage of learning the features automatically from the data while achieving high performance. We compare our CNN model against a feature engineering approach using random forests (RFs). We show that our CNN significantly outperforms the RF model, reducing the error by almost half. Furthermore, for a fixed number of approximately 2000 allowed false transient candidates per night, we are able to reduce the misclassified real transients by approximately one-fifth. To the best of our knowledge, this is the first time CNNs have been used to detect astronomical transient events. Our approach will be very useful when processing images from next generation instruments such as the Large Synoptic Survey Telescope. We have made all our code and data available to the community for the sake of allowing further developments and comparisons at https://github.com/guille-c/Deep-HiTS.
In this paper, we study the disconnection of a moving vehicle from a linear access network composed of cheap WiFi access points in the context of telecommuting in massive transportation systems. In ...concrete, we analyze the probability of a user experiencing a disconnection longer than a given time interval (<inline-formula> <tex-math notation="LaTeX"> t^{*} </tex-math></inline-formula>) such that all ongoing communications between the vehicle and the infrastructure network are disrupted. We provide an approximation formula considering two scenarios (intercity bus and train). We then carry out a sensitivity analysis and supply a guide for operators when choosing the parameters of the networks. Finally, we show that such systems are viable, as they attain a very low probability of long disconnections with a very low maintenance cost.
High cholesterol levels have been linked to a high risk of cardiovascular diseases, and preventative pharmacological care to lower cholesterol levels is critically important. Statins, which are ...hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, are drugs used to reduce the endogenous cholesterol synthesis, thus minimizing its pathophysiological effects. Despite the proven benefits, statins therapy is known to cause a number of skeletal muscle disorders, including myalgia, myopathy and myositis. The mechanisms underlying such statin-induced side effects are unknown. Recently, a group of genes and molecular pathways has been described to participate in statin-induced myopathy, caused by either simvastatin or rosuvastatin, although the mechanism by which changes in gene regulation occur was not studied. Transposable Elements (TEs), repetitive elements that move within the genome, are known to play regulatory roles in gene expression; however, their role in statin-induced muscle damage has not been studied. We analyzed the expression of TEs in human skeletal fiber cells treated with either simvastatin or rosuvastatin, as well as their respective controls, and identified TEs that change their expression in response to the treatment. We found that simvastatin resulted in >1000 differentially expressed (DE) TEs, whereas rosuvastatin resulted in only 27 DE TEs. Using network analysis tools, we predicted the impact of the DE TEs on the expression of genes and found that amongst the genes potentially modulated by TEs, there are some previously associated to statin-linked myopathy pathways (e.g., AKT3). Overall, our results indicate that TEs may be a key player in the statin-induced muscle side effects.
During the analysis of RR Lyrae stars (RRLs) discovered in the High Cadence Transient Survey (HiTS) taken with the Dark Energy Camera at the 4 m telescope at Cerro Tololo Inter-American Observatory, ...we found a group of three very distant, fundamental mode pulsator RR Lyrae (type ab). The location of these stars agrees with them belonging to the Leo V ultra-faint satellite galaxy, for which no variable stars have been reported to date. The heliocentric distance derived for Leo V based on these stars is 173 5 kpc. The pulsational properties (amplitudes and periods) of these stars locate them within the locus of the Oosterhoff II group, similar to most other ultra-faint galaxies with known RRLs. This serendipitous discovery shows that distant RRLs may be used to search for unknown faint stellar systems in the outskirts of the Milky Way.
This study investigates the recent near-surface temperature trends over the Antarctic Peninsula. We make use of available surface observations, ECMWF’s ERA5 and its predecessor ERA-Interim, as well ...as numerical simulations, allowing us to contrast different data sources. We use hindcast simulations performed with Polar-WRF over the Antarctic Peninsula on a nested domain configuration at 45 km (PWRF-45) and 15 km (PWRF-15) spatial resolutions for the period 1991-2015. In addition, we include hindcast simulations of KNMI-RACMO21P obtained from the CORDEX-Antarctica domain (~50 km) for further comparisons. Results show that there is a marked windward warming trend except during summer. This windward warming trend is particularly notable in the autumn season and likely to be associated with the recent deepening of the Amundsen/Bellingshausen Sea low and warm advection towards the Antarctic Peninsula. On the other hand, an overall summer cooling is characterized by the strengthening of the Weddell Sea low as well as an anticyclonic trend over the Amundsen Sea accompanied by northward winds. The persistent cooling trend observed at the Larsen Ice Shelf station is not captured by ERA-Interim, whereas hindcast simulations indicate that there is a clear pattern of windward warming and leeward cooling. Furthermore, larger temporal correlations and lower differences exhibited by PWRF-15 illustrate the existence of the added value in the higher spatial resolution simulation.
We report the discovery of distant RR Lyrae stars, including the most distant known in the Milky Way, using data taken in the g-band with the Dark Energy Camera as part of the High cadence Transient ...Survey (HiTS; 2014 campaign). We detect a total of 173 RR Lyrae stars over a ∼120 deg2 area, including both known RR Lyrae and new detections. The heliocentric distances dH of the full sample range from 9 to >200 kpc, with 18 of them beyond 90 kpc. We identify three sub-groups of RR Lyrae as members of known systems: the Sextans dwarf spheroidal galaxy, for which we report 46 new discoveries, and the ultra-faint dwarf galaxies Leo IV and Leo V. Following an MCMC methodology, we fit spherical and ellipsoidal profiles of the form (R) ∼ Rn to the radial density distribution of RR Lyrae in the Galactic halo. The best fit corresponds to the spherical case, for which we obtain a simple power-law index of , consistent with recent studies made with samples covering shorter distances. The pulsational properties of the outermost RR Lyrae in the sample (dH > 90 kpc) differ from the ones in the halo population at closer distances. The distribution of the stars in a period-amplitude diagram suggest they belong to Oosterhoff-intermediate or Oosterhoff II groups, similar to what is found in the ultra-faint dwarf satellites around the Milky Way. The new distant stars discovered represent an important addition to the few existing tracers of the Milky Way potential in the outer halo.
The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This ...survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the analysis of large data. This work follows a fully data science approach, from the raw data to the analysis and classification of variable sources. We compile a catalog of ∼15 million object detections and a catalog of ∼2.5 million light curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1, and 23.8 in the u, g, r, and i bands, respectively. We classified all point-like nonmoving sources by first extracting features from their light curves and then applying a random forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several random forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3485 sources were classified as variables, of which 1321 were classified as periodic. Among the periodic classes, we discovered with high confidence one δ Scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR Lyrae, and for the nonperiodic classes, we discovered one cataclysmic variable, 630 QSOs, and one supernova candidate. The first data release can be accessed in the project archive of HiTS (http://astro.cmm.uchile.cl/HiTS/).
Trimethylamine (TMA) is the main responsible for the odor associated with rotting fish and other annoying odors generated in many industrial activities. Biofiltration has proved to be efficient for ...treating odorous gaseous emissions. The main objective of this work was to determine the removal capacity of TMA of a biotrickling filter inoculated with Aminobacter aminovorans and to evaluate the effect of H2S on its performance.
The maximum specific growth rate of A. aminovorans in a liquid culture was 0.15 h-1, with a TMA to biomass yield of 0.10 (g g-1) and a specific consumption rate of 0.062 g·g-1·h-1. The initial specific consumption rate of TMA was highly influenced by the presence of H2S in liquid culture at concentrations of 20 and 69 ppm in heading space of the flasks. A BTF inoculated with A. aminovorans showed removal efficiencies higher than 98% in a range of loading rate of 0.2 to 8 g·m-3·h-1 at empty bed residence time (EBRT) of 85 and 180 s. No effect on the elimination capacity and efficiency was detected when H2S was added at 20 and 50 ppm to the inlet gaseous emission, though the fraction of A. aminovorans measured by qPCR in the biofilm decreased.
A biotrickling filter inoculated with A. aminovorans can remove efficiently the TMA in a gaseous stream. The elimination capacity of TMA can be negatively affected by H2S, but its effect is not notorious when it is forming part of a biofilm, due to its high specific consumption rate of TMA.
How to cite: Aguirre A, Bernal P, Maureira D, et al. Biofiltration of trimethylamine in biotrickling filter inoculated with Aminobacter aminovorans. Electron J Biotechnol 2018;33. https://doi.org/10.1016/j.ejbt.2018.04.004.
The objective of the present study is to evaluate the psychometric properties of the Scale of Attitudes toward Gender Equality in Football in the Context of Schools (SAGEFS) in the international ...context. This sample was formed by
= 6,101 students. The study was conducted by applying the SAGEFS. The model of the three factors correlated in the complete sample and for each country was correlated using AFC. The structural model was appraised by employing eight indices: the relative Chi-squared index; the goodness of fit index and its adjusted formula; the normal fit index; the comparative fit index; the standardized Quadratic Mean; and the Quadratic Mean Error of Approximation. To conclude, the results evidence the presence of psychometric properties that are indispensable for the measurement of attitudes toward gender equality in the context of schools.
Copper, an ion with many important metabolic functions, has also been proposed to have a role as modulator on neuronal function, mostly based on its effects on voltage‐ and neurotransmitter‐gated ...conductance as well as on neurological symptoms of patients with altered copper homeostasis. Nevertheless, the mechanisms by which copper exerts its neuromodulatory effects have not been clearly established in a functional neuronal network. Using rat hippocampus slices as a neuronal network model, the effects of copper in the range of 10–100 nm were tested on the intrinsic, synaptic and network properties of the CA1 region. Most of the previously described effects of this cation were in the micromolar range of copper concentrations. The current results indicate that copper is a multifaceted neuromodulator, having effects that may be grouped into two categories: (i) activity enhancement, by modulating synaptic communication and action potential (AP) conductances; and (ii) temporal processing and correlation extraction, by improving reliability and depressing inhibition. Specifically it was found that copper hyperpolarizes AP firing threshold, enhances neuronal and network excitability, modifies CA3–CA1 pathway gain, enhances the frequency of spontaneous synaptic events, decreases inhibitory network activity, and improves AP timing reliability. Moreover, copper chelation by bathocuproine decreases spontaneous network spiking activity. These results allow the proposal that copper affects the network activity from cellular to circuit levels on a moment‐by‐moment basis, and should be considered a crucial functional component of hippocampal neuronal circuitry.
We document copper's operational closure conveying synaptic, action potential and network activity modulations. Cu2+ at nm range, amplify signaling through the hippocampal network with no alterations in jittering but improving reliability of spike trains. In excess, Cu2+ may induce a plethora of redox‐related deleterious effects; its deficit in turn will compromise the gain of this operational closure. We propose this mechanism for Wilson and Menkes neurological conditions.
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