Chemical abundances of stars with brown-dwarf companions

It is well-known that stars with giant planets are on average more metal-rich than stars without giant planets, whereas stars with detected low-mass planets do not need to be metal-rich. With the aim of studying the weak boundary that separates giant planets and brown dwarfs (BDs) and their formation mechanism, we analyze the spectra of a sample of stars with already confirmed BD companions both by radial velocity and astrometry. We employ standard and automatic tools to perform an EW-based analysis and to derive chemical abundances from CORALIE spectra of stars with BD companions. We compare these abundances with those of stars without detected planets and with low-mass and giant-mass planets. We find that stars with BDs do not have metallicities and chemical abundances similar to those of giant-planet hosts but they resemble the composition of stars with low-mass planets. The distribution of mean abundances of $\alpha$-elements and iron peak elements of stars with BDs exhibit a peak at about solar abundance whereas for stars with low-mass and high-mass planets the [X$_\alpha$/H] and [X$_{\rm Fe}$/H] peak abundances remain at $\sim -0.1$~dex and $\sim +0.15$~dex, respectively. We display these element abundances for stars with low-mass and high-mass planets, and BDs versus the minimum mass, $m_C \sin i$, of the most-massive substellar companion in each system, and we find a maximum in $\alpha$-element as well as Fe-peak abundances at $m_C \sin i \sim 1.35\pm 0.20$ jupiter masses. We discuss the implication of these results in the context of the formation scenario of BDs in comparison with that of giant planets.Comment: Accepted for publication in Astronomy & Astrophysic

Analysis of the consumption of sports supplements in elite fencers according to sex and competitive level.

Background: The aim of this study was to analyze the consumption of sports supplements (SS) in competitive level fencers and compare differences based on sex and competitive level (international and national). Methods: A total of 49 fencers (18 men and 31 women) of national (n = 16) and international (n = 33) level completed a questionnaire with questions about SS consumption and the possible repercussions on health and / or sports performance. The results were analyzed based on the different categorizations established by the Australian Institute of Sport (AIS), as well as by sex and level of competence to which the participants belonged to. Results: 46.9% of fencers have consumed SS with the main motivation being performance improvement (34.2%). Medical doctors were the individuals who were more likely to advise men to consume SS (50.0% vs 5.6%; OR = 3.29 [1.50–7.20]). Friends were most likely to advise women (38.9% vs 8.3%; OR = 1.75 [1.05–2.93]). The most consumed SS were sport drinks (44.9%), vitamin C (43.4%), sport bars (38.8%), and caffeine (28.6%). In regards to the SS categories, it was observed differences in the interaction level·sex in medical supplements (p = 0.017). In addition, there was a higher prevalence of whey protein consumption in women (25.8% vs 0%; p = 0.020) and iron consumption in men (33% vs 6.5%; p = 0.039). Conclusions: The prevalence of SS use in fencers is within the values previously reported in athletes of the same competitive level. There were no differences by sex and competitive level in the total consumption of SS, nor in each of the groups of level of evidence, being sport drinks, bars and caffeine the most consumed SS.post-print572 K

The Use of ICTs in Teaching at the Normal Superior School “Profr. Moisés Sáenz Garza”: An Exploratory Study

The use of ICTs in the classroom is studied in a descriptive exploratory way to favor the professional training process in the Normal Superior School “Profr. Moisés Sáenz Garza” based on the 2018 study plan. A survey was applied to teachers of eight specialties from different semesters. The questionnaire evaluated the frequency dimensions of the use of ICTs, the use of technological resources in teaching, the teacher’s communication process with students, and the usefulness of ICTs in class for teachers. The main results express that the use of ICTs is systematic and conceived as permanent support for the training path. The main means of teacher-student communication are email and the Moodle educational platform, while the most common activities carried out on the platform are exams, guidelines and forums. The established teachers agree in accepting and recognizing the need for ICTs to make the teaching-learning process more efficient. In general, the use of ICTs in the school studied is satisfactory, which is explained by the fact that the institution has the necessary technological infrastructure for academic activity

Synthesis of degradable cationic carbosilane dendrimers based on Si-O or ester bonds

Several cationic carbosilane dendrimers have been synthesized containing two different types of degradable bonds: SieO and ester bonds. The first type of systems was prepared by reacting carbosilane dendrimers containing peripheral SieCl bonds with first generation dendrons presenting a eOH function at the focal point and amine peripheral functions. The second type of systems was prepared by esterification between a dendrimer containing acid groups and an alcoholamine. The stability in water of both types of cationic systems was evaluatedMinisterio de Economía y Empres

Half-sandwich isocyanide, phosphine, methyl and phosphanido pentamethylcyclopentadienylniobium(V) complexes

[NbCp★Cl4] Cp★ = ν5-C5Me5) reacts with one molar equivalent of isocyanides and phosphines to give pseudo-octahedral adducts [NbCp★Cl4·L], (Full-size image (<1 K), 4) and the dinuclear complex [∗[NbCp★Cl4∗]2(μ-dmpe)], 5. Reactions of [NbCp★Cl4] with appropriate amounts of MgClMe yield the correspodning dimethyl [NbCp★Cl2Me2], 6, and tetramethyl [NbCp★Me4], 7 derivatives. Similarly, when [∗[NbCp★Cl3∗2(μ-O)] an and 3 are treated with the alkylating magnesium reagent, [∗[NbCp★Me3∗]2(μ-O)], 8, and [NbCp★Cl3Me(PMe2Ph)], 9, are obtained in high yields. A new phosphanido-niobium(V) complex [NbCp★Cl3(PPh2)] 10, is formed in the reaction of the starting tetrachloro complex with one equivalent of LiPPh2. All the complexes were characterized by IR and NMR spectroscopy, and most of them were studied by mass spectrometry

Ask The Machine: Systematic detection of wind-type outflows in low-mass X-ray binaries

The systematic discovery of outflows in the optical spectra of low-mass X-ray binaries opened a new avenue for the study of the outburst evolution in these extreme systems. However, the efficient detection of such features in a continuously growing database requires the development of new analysis techniques with a particular focus on scalability, adaptability, and automatization. In this pilot study, we explore the use of machine learning algorithms to perform the identification of outflows in spectral line profiles observed in the optical range. We train and test the classifier on a simulated database, constructed through a combination of disc emission line profiles and outflow signatures, emulating typical observations of low-mass X-ray binaries. The final, trained classifier is applied to two sets of spectra taken during two bright outbursts that were particularly well covered, those of V404 Cyg (2015) and MAXI J1820+070 (2018). The resulting classification gained by this novel approach is overall consistent with that obtained through traditional techniques, while it simultaneously provides a number of key advantages over the latter, including the access to low velocity outflows. This study sets the foundations for future studies on large samples of spectra from low-mass X-ray binaries and other compact binaries.Comment: Accepted for publication in MNRAS. 13 pages, 6 figure

EL GÉNERO UTRICULARIA L. (LENTIBULARIACEAE) EN EL SISTEMA CENTRAL ESPAÑOL

A revision of the genus Utricularia L. in the Spanish Central System is undertaken. The recognized taxa are delimited and drawn as well as information on their distribution and ecology are provided.Se efectúa la revisión del género Utricularia L. en el Sistema Central español. Se delimitan e iconografían los distintos táxones reconocidos y se aportan datos sobre su distribución y ecología

Study of non-covalent interactions on dendriplex formation: Influence of hydrophobic, electrostatic and hydrogen bonds interactions

The interaction of a double stranded small interference RNA (siRNA Nef) with cationic carbosilane dendrimers of generations 1-3 with two different ammonium functions at the periphery ([-NMe2R](+), R=Me, (CH2)(2)OH) has been studied by experimental techniques (zeta potential, electrophoresis, single molecule pulling experiments) and molecular dynamic calculations. These studies state the presence of different forces on dendriplex formation, depending on generation and type of ammonium group. Whilst for higher dendrimers electrostatic forces mainly drive the stability of dendriplexes, first generation compounds can penetrate into siRNA strands due to the establishment of hydrophobic interactions. Finally, in the particular case of first generation dendrimer [G(1)O(3)(NMe2(CH2)(2)OH))(6)](6+); the presence of hydroxyl groups reinforces dendriplex stability by hydrogen bonds formation. However, since these small dendrimers do not cover the RNA, only higher generation derivatives protect RNA from degradation.University of Alcalá; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN); Instituto de Investigación Sanitaria Gregorio Marañón; Universitat de Barcelon

Strategies for penicillin V dendronization with cationic carbosilane dendrons and study of antibacterial properties.

Strategies to synthesize a cationic carbosilane dendron containing the antibiotic penicillin V potassium salt (PenVK) at the focal point are discussed. The preparation of such a compound requires the use of systems with no donor atoms such as N or S in their framework, because their presence favours the rupture of the penicillin beta-lactam ring. The antibacterial activity of the new dendron containing ammonium groups, at the periphery, and the PenV moiety, at the focal point, against gram-positive Staphylococcus aureus strains was evaluated. These results were compared with those obtained for free PenVK, a related cationic dendron without a penicillin moiety at the focal point, and also compared with an equimolar mixture of this last dendron with free PenV. The data obtained indicate that, on one hand, the conjugation or interaction of PenV with cationic dendrons reduces its activity in comparison with free PenVK. On the other hand, the penicillin dendron is able to release the antibiotic in the presence of esterease, due to the breaking of the ester bond in this derivative.Ministerio de Economía y Empres