Short-lived spots in solar-like stars as observed by CoRoT

Context. CoRoT light curves have an unprecedented photometric quality, having simultaneously a high signal-to-noise ratio, a long time span and a nearly continuous duty-cycle. Aims. We analyse the light-curves of four bright targets observed in the seismology field and study short-lived small spots in solar-like stars. Methods. We present a simple spot modeling by iterative analysis. Its ability to extract relevant parameters is ensured by implementing relaxation steps to avoid convergence to local minima of the sum of the residuals between observations and modeling. The use of Monte-Carlo simulations allows us to estimate the performance of the fits. Results. Our starspot modeling gives a representation of the spots on these stars in agreement with other well tested methods. Within this framework, parameters such as rigid-body rotation and spot lifetimes seem to be precisely determined. Then, the lifetime/rotation period ratios are in the range 0.5 - 2, and there is clear evidence for differential rotation.Comment: 11 pages Accepted in A&

Centauri honey: a promising medicinal ingredient?

Honey is a natural product that has been used over the centuries as a medicine due to its biological activities. Centauri Cave Nymph Honey is a Cave honey extracted from 2500 meters high altitude above sea level from a deep cave by professional speleologists and is located at Caucasus Mountains of Turkey. The Apis mellifera Caucasica bee colony is located 50 kilometers away from human residences, ensuring its isolation from other colonies and maintaining a varroa mite-free status. The aim of this work is to analyze the physicochemical parameters and the bioactivity of Centauri honey. The physiochemical parameters that have been examined include color, moisture content, conductivity, pH, acidity, HMF (5-hydroxymethylfurfural), diastase index, and proline. In addition, it was also evaluated the ash, protein, sugars, carbohydrates, and energy. The biological activity was evaluated through the antioxidant (TBARS), antimicrobial activities and cytotoxicity in different cell lines (AGS, CaCo-2, MCF-7, NCI-H460, PLP2, HFF-2, and HaCat), and anti-inflammatory activity (RAW 264.7 macrophages). Ongoing research is focusing on the potential protetive effects of consuming Centauri Cave Honey against lung and prostate cancers. In vivo studies are expected to shed more ligt on the additional health benefits that this honey may offer.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CIMO (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC (LA/P/0007/2021).info:eu-repo/semantics/publishedVersio

Medicinal centauri honey: a promising ingredient?

Honey is a natural product with antioxidant and antimicrobial properties, has been used as a medicinal substance for centuries. Thisnatural product is main- ly composed of a supersaturated solution of sugars, containing low water con- tent and trace amounts of bioactive compounds. The flower source, climate, geographical origin, harvesting process and storage conditions are factors that influence the composition of the nectar, leading to significant changes in the chemical composition, physical properties, and bioactivity of honey1. Centau- ri Honey is harvested from bee colonies located in the wild Alps of Turkey ́s mountainous region, approximately 2,500 meters above the Black Sea. The bees live in caves far from human settlements and other bees, and they have access to medicinal endemic blooms throughout the year. The aim of this work was to investigate the quality, physicochemical, nutrition- al parameters, and bioactivity of honey. The quality and physiochemical pa- rameters was analysed by colour, moisture content, conductivity, pH and acidity, 5-HMF (5-Hydroxymethylfurfural), diastase index and proline. The nutritional values were determined assessing ash, protein content, sugars, carbohydrates and energy. The biological activity was evaluated through the antioxidant, antimicrobial activity (broth microdilution method) and cytotox- icity in cell lines (AGS, CaCo-2, MCF-7, NCI-H460, PLP2, HFF-2, and HaCat), and anti-inflammatory activity (using RAW 264.7 macrophages). Further studies are ongoing to scientifically validate the medicinal properties of Centauri Honey due to its exceptional chemical composition and thus to become an innovative Ingredient.info:eu-repo/semantics/publishedVersio

Biological activity of 6,7-dehydroroyleanone derivatives from Plectranthus aliciae

Plectranthus genus (Lamiaceae) is known to be rich in bioactive abietane royleanone-type diterpenes, such as 6,7-dehydroxyroyleanone (1, Fig. 1), which have been previously found in P. madagascariensis (var. aliciae Codd). This abietane royleanone presents moderate to significant to cytoxic activity against several cancer cell lines. Moreover, 1 has one hydroxyl group suitable for deri- vatization that can be explored to enhance the cytotoxic activity of lead com- pound 1. Based on this, the aim of the present work is to explore the obtention of 1, from P. aliciae aliciae (Codd) van Jaarsv. & T.J.Edwards., a subspecies of P. madagascariensis to be further used in the preparation of new derivatives with enhanced biological activities.info:eu-repo/semantics/publishedVersio

Revisiting the transits of CoRoT-7b at a lower activity level

CoRoT-7b, the first super-Earth with measured radius discovered, has opened the new field of rocky exoplanets characterisation. To better understand this interesting system, new observations were taken with the CoRoT satellite. During this run 90 new transits were obtained in the imagette mode. These were analysed together with the previous 151 transits obtained in the discovery run and HARPS radial velocity observations to derive accurate system parameters. A difference is found in the posterior probability distribution of the transit parameters between the previous CoRoT run (LRa01) and the new run (LRa06). We propose this is due to an extra noise component in the previous CoRoT run suspected to be transit spot occultation events. These lead to the mean transit shape becoming V-shaped. We show that the extra noise component is dominant at low stellar flux levels and reject these transits in the final analysis. We obtained a planetary radius, $R_p= 1.585\pm0.064\,R_{\oplus}$, in agreement with previous estimates. Combining the planetary radius with the new mass estimates results in a planetary density of $1.19 \pm 0.27\, \rho_{\oplus}$ which is consistent with a rocky composition. The CoRoT-7 system remains an excellent test bed for the effects of activity in the derivation of planetary parameters in the shallow transit regime.Comment: 13 pages, 13 figures, accepted to A&

Multiwavelength flux variations induced by stellar magnetic activity: effects on planetary transits

Stellar magnetic activity is a source of noise in the study of the transits of extrasolar planets. It induces flux variations which affect significantly the transit depth determination and the derivations of planetary and stellar parameters. Furthermore, the colour dependence of stellar activity may significantly influence the characterization of planetary atmospheres. Here we present a systematic approach to quantify the corresponding stellar flux variations as a function of wavelength bands. We consider a star with spots covering a given fraction of its disc and model the variability in the UBVRIJHK photometric system and in the Spitzer/IRAC wavebands for dwarf stars from G to M spectral types. We compare activity-induced flux variations in different passbands with planetary transits and quantify how they affect the determination of the planetary radius and the analysis of the transmission spectroscopy in the study of planetary atmospheres. We suggest that the monitoring of the systems by using broad band photometry, from visible to infrared, helps to constraining activity effects. The ratio of the relative variations of the stellar fluxes in short wavelength optical bands (e.g., U or B) to near infrared ones (e.g., J or K) can be used to distinguish starspot brightness dips from planetary transits in a stellar light curve. In addition to the perturbations in the measurement of the planetary radius, we find that starspots can affect the determination of the relative semimajor axis and the inclination of the planetary orbit which have a significant impact on the derivation of the stellar density from the transit light curves.Comment: 12 pages, 6 Postscript figure

Plectranthus madagascariensis phytosomes

Medicinal plants have been a reliable source of bioactive natural products with potential pharmaceutical applications. The delivery of those bioactive agents into nanosystems is considered a promising strategy for the optimization of their pharmacologic effects. This work describes the preparation of phytosomes containing a bioactive extract from Plectranthus madagascariensis and optimization of the preparation method. Different formulations and process parameters were studied. It was observed that smaller and more uniform particles were obtained using acetone as solvent, a reaction time of two hours, and the addition of 2.5% molar concentration of cholesterol. The optimally prepared phytosomes had a diameter of 191.3 ± 75.3 nm with a polydispersity index of 0.243 ± 0.18, and a spherical shape with amorphous appearance. These nanosystems were able to encapsulate 92.8% of the extract, as evaluated by HPLC, relative to 7α,6β-dihydroxyroyleanona, the main extract component. This study suggests a future application of those phytosomes in the delivery of bioactive agents with therapeutic interest

The effects of artificial rearing and fostering on the growth, carcass and meat quality of lambs

Lamb rearing is a key point to ensure good quality at the end of the production cycle. Fostering and artificial rearing are techniques commonly used when natural rearing is compromised. However, there is a lack of research investigating their impact on the product´s quality, especially when lambs are slaughtered late, around 6 months of age. The current study investigated the effects of artificially reared and fostered lambs on growth, carcass and meat quality. The three foster methods under study were birth fluids, cervical stimulation combined with birth fluids and restraint. Animals were weaned at 3 months of age, and processed at 6 months of age. Artificially reared lambs presented lower weight gains than ewe reared ones at young ages. They also presented worse conformation scores at the processing plant. No differences could be found for growth rates, carcass or meat quality among the foster methods tested

Multi-band high resolution spectroscopy rules out the hot Jupiter BD+20 1790b - First data from the GIARPS Commissioning

Context. Stellar activity is currently challenging the detection of young planets via the radial velocity (RV) technique. Aims. We attempt to definitively discriminate the nature of the RV variations for the young active K5 star BD+20 1790, for which visible (VIS) RV measurements show divergent results on the existence of a substellar companion. Methods. We compare VIS data with high precision RVs in the near infrared (NIR) range by using the GIANO - B and IGRINS spectrographs. In addition, we present for the first time simultaneous VIS-NIR observations obtained with GIARPS (GIANO - B and HARPS - N) at Telescopio Nazionale Galileo (TNG). Orbital RVs are achromatic, so the RV amplitude does not change at different wavelengths, while stellar activity induces wavelength-dependent RV variations, which are significantly reduced in the NIR range with respect to the VIS. Results. The NIR radial velocity measurements from GIANO - B and IGRINS show an average amplitude of about one quarter with respect to previously published VIS data, as expected when the RV jitter is due to stellar activity. Coeval multi-band photometry surprisingly shows larger amplitudes in the NIR range, explainable with a mixture of cool and hot spots in the same active region. Conclusions. In this work, the claimed massive planet around BD+20 1790 is ruled out by our data. We exploited the crucial role of multi- wavelength spectroscopy when observing young active stars: thanks to facilities like GIARPS that provide simultaneous observations, this method can reach its maximum potential.Comment: 12 pages, 7 figure