Zebrafish have a remarkable capacity to regenerate their heart. Efficient replenishment of lost tissues requires the activation of different cell types including the epicardium and endocardium. A ...complex set of processes is subsequently needed to support cardiomyocyte repopulation. Previous studies have identified important determinants of heart regeneration; however, to date, how revascularization of the damaged area happens remains unknown. Here, we show that angiogenic sprouting into the injured area starts as early as 15 h after injury. To analyze the role of vegfaa in heart regeneration, we used vegfaa mutants rescued to adulthood by vegfaa mRNA injections at the one-cell stage. Surprisingly, vegfaa mutants develop coronaries and revascularize after injury. As a possible explanation for these observations, we find that vegfaa mutant hearts up-regulate the expression of potentially compensating genes. Therefore, to overcome the lack of a revascularization phenotype in vegfaa mutants, we generated fish expressing inducible dominant negative Vegfaa. These fish displayed minimal revascularization of the damaged area. In the absence of fast angiogenic revascularization, cardiomyocyte proliferation did not occur, and the heart failed to regenerate, retaining a fibrotic scar. Hence, our data show that a fast endothelial invasion allows efficient revascularization of the injured area, which is necessary to support replenishment of new tissue and achieve efficient heart regeneration. These findings revisit the model where neovascularization is considered to happen concomitant with the formation of new muscle. Our work also paves the way for future studies designed to understand the molecular mechanisms that regulate fast revascularization.
Global solar broadband irradiance on a planar surface is measured at weather stations by pyranometers. In the case of the present research, solar radiation values from nine meteorological stations of ...the MeteoGalicia real-time observational network, captured and stored every ten minutes, are considered. In this kind of record, the lack of data and/or the presence of wrong values adversely affects any time series study. Consequently, when this occurs, a data imputation process must be performed in order to replace missing data with estimated values. This paper aims to evaluate the multivariate imputation of ten-minute scale data by means of the chained equations method (MICE). This method allows the network itself to impute the missing or wrong data of a solar radiation sensor, by using either all or just a group of the measurements of the remaining sensors. Very good results have been obtained with the MICE method in comparison with other methods employed in this field such as Inverse Distance Weighting (IDW) and Multiple Linear Regression (MLR). The average RMSE value of the predictions for the MICE algorithm was 13.37% while that for the MLR it was 28.19%, and 31.68% for the IDW.
State-of-charge (SOC) is the equivalent of a fuel gauge for a battery pack in an electric vehicle. Determining the state-of-charge becomes an important issue in all battery applications including ...electric vehicles (EV), hybrid electric vehicles (HEV) or portable devices. The aim of this innovative study is to estimate the SOC of a high capacity lithium iron phosphate (LiFePO4) battery cell from an experimental data-set obtained in the University of Oviedo Battery Laboratory (UOB Lab) using support vector machine (SVM) approach. The SOC of a battery cannot be measured directly and must be estimated from measurable battery parameters such as current, voltage or temperature. An accurate predictive model able to forecast the SOC in the short term is obtained. The agreement of the SVM model with the experimental data-set confirmed its good performance.
Cyanotoxins, a kind of poisonous substances produced by cyanobacteria, are responsible for health risks in drinking and recreational water uses. The aim of this study is to improve our previous and ...successful work about cyanotoxins prediction from some experimental cyanobacteria concentrations in the Trasona reservoir (Asturias, Northern Spain) using the multivariate adaptive regression splines (MARS) technique at a local scale. In fact, this new improvement consists of using not only biological variables, but also the physical–chemical ones. As a result, the coefficient of determination has improved from 0.84 to 0.94, that is to say, more accurate predictive calculations and a better approximation to the real problem were obtained. Finally the agreement of the MARS model with experimental data confirmed the good performance.
► An improved MARS model is built as a predictive model of cyanotoxins presence. ► Cyanobacterial HABs are dangerous for environment and people in fresh waters. ► Biological and physical–chemical variables in this process are studied in depth.
Emission of methane from plants Nisbet, R.E.R; Fisher, R; Nimmo, R.H ...
Proceedings of the Royal Society. B, Biological sciences,
04/2009, Letnik:
276, Številka:
1660
Journal Article
Recenzirano
Odprti dostop
It has been proposed that plants are capable of producing methane by a novel and unidentified biochemical pathway. Emission of methane with an apparently biological origin was recorded from both ...whole plants and detached leaves. This was the first report of methanogenesis in an aerobic setting, and was estimated to account for 10-45 per cent of the global methane source. Here, we show that plants do not contain a known biochemical pathway to synthesize methane. However, under high UV stress conditions, there may be spontaneous breakdown of plant material, which releases methane. In addition, plants take up and transpire water containing dissolved methane, leading to the observation that methane is released. Together with a new analysis of global methane levels from satellite retrievals, we conclude that plants are not a major source of the global methane production.
In recent years, there has been increasing interest in the role of lymphatics in organ repair and regeneration, due to their importance in immune surveillance and fluid homeostasis. Experimental ...approaches aimed at boosting lymphangiogenesis following myocardial infarction in mice, were shown to promote healing of the heart. Yet, the mechanisms governing cardiac lymphatic growth remain unclear. Here, we identify two distinct lymphatic populations in the hearts of zebrafish and mouse, one that forms through sprouting lymphangiogenesis, and the other by coalescence of isolated lymphatic cells. By tracing the development of each subset, we reveal diverse cellular origins and differential response to signaling cues. Finally, we show that lymphatic vessels are required for cardiac regeneration in zebrafish as mutants lacking lymphatics display severely impaired regeneration capabilities. Overall, our results provide novel insight into the mechanisms underlying lymphatic formation during development and regeneration, opening new avenues for interventions targeting specific lymphatic populations.
Cyanotoxins, a kind of poisonous substances produced by cyanobacteria, are responsible for health risks in drinking and recreational waters. As a result, anticipate its presence is a matter of ...importance to prevent risks. The aim of this study is to use a hybrid approach based on support vector regression (SVR) in combination with genetic algorithms (GAs), known as a genetic algorithm support vector regression (GA–SVR) model, in forecasting the cyanotoxins presence in the Trasona reservoir (Northern Spain). The GA-SVR approach is aimed at highly nonlinear biological problems with sharp peaks and the tests carried out proved its high performance. Some physical–chemical parameters have been considered along with the biological ones. The results obtained are two-fold. In the first place, the significance of each biological and physical–chemical variable on the cyanotoxins presence in the reservoir is determined with success. Finally, a predictive model able to forecast the possible presence of cyanotoxins in a short term was obtained.
► A hybrid GA–SVR model is built as a predictive model of cyanotoxins presence. ► Cyanobacterial HABs are dangerous for environment and people in fresh waters. ► Biological and physical. ► chemical variables in this process are studied in depth. ► The obtained regression accuracy of our method is 98%. ► The results show that GA–SVR model can assist in the diagnosis of cyanotoxins.
► A hybrid GA–MARS model is built as a predictive model of cyanotoxins presence. ► Cyanobacterial HABs are dangerous for environment and people in fresh waters. ► Biological and physical–chemical ...variables in this process are studied in depth. ► The obtained regression accuracy of our method is 98%. ► The results show that GA–MARS model can assist in the diagnosis of cyanotoxins.
Cyanobacteria are one of the major concerns to public health since some of them produce a range of potent toxins (cyanotoxins). This group of microorganism can be present in drinking and recreation waters representing a health risk for animals and human being. For this reason, as prevention, it is important to bring forward their presence. In this study, using physical–chemical and biological parameters, a hybrid approach based on genetic algorithms (GAs) combined with the multivariative adaptative regression splines (MARS) technique, was developed and applied for forecasting the presence of cyanobacteria in a water reservoir (Trasona reservoir, Northern Spain) and in consequence, the cyanotoxin risk. The significance of each biological and physical–chemical variables used for its determination was assessed and a predictive model useful for preventing the presence of cyanobacteria, and consequently of cyanotoxins, was defined.
ABSTRACT
We analysed the photometry of 20 038 cool stars from campaigns 12, 13, 14, and 15 of the K2 mission in order to detect, characterize, and validate new planetary candidates transiting ...low-mass stars. We present a catalogue of 25 new periodic transit-like signals in 22 stars, of which we computed the parameters of the stellar host for 19 stars and the planetary parameters for 21 signals. We acquired speckle and AO images, and also inspected archival Pan-STARRS1 images and Gaia DR2 to discard the presence of close stellar companions and to check possible transit dilutions due to nearby stars. False positive probability (FPP) was computed for 22 signals, obtaining FPP < $1{{\ \rm per\ cent}}$ for 17. We consider 12 of them as statistically validated planets. One signal is a false positive and the remaining 12 signals are considered as planet candidates. 20 signals have an orbital period of P$_{\rm orb} \lt 10\,\mathrm{ d}$, 2 have $10\, \mathrm{ d} \lt $ P$_{\rm orb} \lt 20\, \mathrm{ d}$, and 3 have P$_{\rm orb} \gt 20\, \mathrm{ d}$. Regarding radii, 11 candidates and validated planets have computed radius R < 2R⊕, 9 have 2R⊕ < R < 4R⊕, and 1 has R > 4R⊕. Two validated planets and two candidates are located in moderately bright stars ($\rm \mathit{ m}_{kep}\lt 13$) and two validated planets and three candidates have derived orbital radius within the habitable zone according to optimistic models. Of special interest is the validated warm super-Earth K2-323 b (EPIC 248616368 b) with T$_{\rm eq} = 318^{+24}_{-43} \, \mathrm{ K}$, S$_{\rm p} = 1.7\pm 0.2 \, \mathrm{ S}_{\oplus }$, and R$_{\rm p} = 2.1\pm 0.1 \, \mathrm{ R}_{\oplus }$, located in an m$\rm _{kep}$ = 14.13 star.
ABSTRACT
We present a super-Earth orbiting close to the inner edge of the habitable zone of the cool dwarf star K2-286 (EPIC 249889081), detected with data from the K2 mission in its 15th campaign. ...The planet has radius of 2.1 ± 0.2 R⊕, near the 1.5–2.0 R⊕ gap in the radii distribution. The equilibrium temperature is $347^{+21}_{-11}$ K, cooler than most of the small planets with well-measured masses, and the orbital period is 27.359 ± 0.005 d. K2-286, located at a distance of 76.3 ± 0.3 pc, is an M0V star with estimated effective temperature of 3926 ± 100 K, less active than other M dwarf stars hosting exoplanets. The expected radial velocity semi-amplitude induced by the planet on the star is $1.9^{+1.3}_{-1.2}$ m s−1, and the amplitude of signals in transit transmission spectroscopy is estimated at 5.0 ± 3.0 ppm. Follow-up observations for mass measurements and transit spectroscopy should be desirable for this relatively bright target (mV = 12.76, mKs = 9.32) hosting a transiting super-Earth within the inner edge of the habitable zone.
PDF
