Vegetation

Due to their complexity, vegetation phenomena are not understandable without a consistent conceptual framework. A few indispensable concepts to explore the northeastern Portuguese ultramafic vegetation are set out in Tables 9 and 10. Association. The Phytosociology fundamental abstract unit is the association or associatio. The concept of association comprises an ecological-taxonomic model of the reality. Therefore, the association includes the notion of a plant community (biological information: floristic, physiognomic etc.) that occupies a particular biotope (chorologic information) where a specific set of environmental conditions can be found, i.e. the habitat (environmental information). The taxonomic element is mainly supported on the floristic composition, which is characteristic and statistically constant between associations. The development of a hierarchical syntaxonomic system (synsystem) is based above all on floristic, but also on environmental, biogeographic and physiognomic characters. Although the association concept is not a true synonym of phytocoenosis the two terms are often used interchangeably, which may result abusiv

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

Flora

The invaluable commented checklist of the vascular flora of the ultramafic rocks of northeastern Portugal of Pinto da Silva (1970) has been recently reviewed by Aguiar and Monteiro-Henriques (ined.). These authors’ accept 568 taxa, 29% of which (164 taxa) are new additions to the original catalogue of Pinto da Silva (1970). A subset of it with the most frequent and floristically relevant species is presented in Table 6. New additions have been highlighted with an asterisk (*). The most noticeable neophytes have been included and marked with an open rhombus (◊). A few synonyms have been added to facilitate the reading of the list of Pinto da Silva (1970). Familiar circumscription and higher taxa are according, respectively, to APG III (2009) and Chase & Reveal (2009). The main sources of infrafamiliar taxonomic information were the Flora Iberica (Castroviejo 1981+), Nova Flora de Portugal (Franco 1971; 1984; Franco & Rocha Afonso (1994; 1998), The Checklist of the Portuguese Vascular Flora (Sequeira et al. 2011) and, among others, the taxonomic revisions of Romero et al. (1988) (Agrostis), Díaz Lifante & Valdés (1996) (Asphodelus), La Guardia & Blanca (1987) (Scorzonera), Schippmann (1991) and Voght (1991) (Leucanthemum). We followed different taxonomic or nomenclatural criteria from Flora Iberica or Nova Flora de Portugal in Armeria langei subsp. marizii, Anthyllis sampaioana, A. vulneraria subsp. lusitanica, Alyssum serpyllifolium subsp. lusitanicum, Asplenium adiantum-nigrum subsp. corunnense, Carlina hispanica, Centaurea langei, Festuca elegans subsp. merinoi, Helianthemum apenninum subsp. rothmaleri, Tuberaria guttata and Trifolium striatum var. brevidens. The preparation of a checklist of ultramafic vascular flora is a difficult task. First of all, flora checklists are unfinished assignments because plants come and go with time. On the other hand, the northeastern Portugal ophiolites lithology is heterogeneous and complex. Peridotites, and similar ultramafic rocks, appear in stretched outcrops dispersed among macromorphologically similar basic rocks. The soils that have covered the ultramafic rocks many times catch materials from nearby mafic and leucocratic rocks. Finally, deep soils, rich in organic matter, derived from ultramafic rocks, usually have a similar flora to other nearby lithologies. The serpentine effect is in practice impossible to spatialize and quantify; consequently an ultramafic vascular flora checklist brings together plants of rather diverse ecology, and is by itself of limited scientific value

The 1989 and 2015 outbursts of V404 Cygni: a global study of wind-related optical features

Peer ReviewedPreprin

First measurement of the total gravitational quadrupole moment of a black widow companion

We present the first measurement of the gravitational quadrupole moment of the companion star of a spider pulsar, namely the black widow PSR J2051–0827. To this end, we have re-analysed radio timing data using a new model that is able to account for periastron precession caused by tidal and centrifugal deformations of the star as well as by general relativity. The model allows for a time-varying component of the quadrupole moment, thus self-consistently accounting for the ill-understood orbital period variations observed in these systems. Our analysis results in the first detection of orbital precession in a spider system at ω˙=−68∘.6+0∘.9−0∘.5 yr−1 and the most accurate determination of orbital eccentricity for PSR J2051–0827 with e = (4.2 ± 0.1) × 10−5. We show that the variable quadrupole component is about 100 times smaller than the average quadrupole moment Q¯=−2.2+0.6−1×1041 kgm2⁠. We discuss how accurate modelling of high-precision optical light curves of the companion star will allow its apsidal motion constant to be derived from our results

Development of a novel duplex lateral flow test for simultaneous detection of casein and ß-lactoglobulin in food

Milk by-products such as whey and caseinate are widely used as ingredients or processing aids in food industry. However, since they could cause allergic reactions they are included in Allergen Control Plans. ß-Lactoglobulin is the major whey protein and caseins are main proteins in milk. Selection of a unique target to analyze the presence of milk in foods could be insufficient when the source of milk proteins is unknown. A new test based on lateral flow immunocromatography that combines the simultaneous and independent detection of both proteins (ß-lactoglobulin and casein)in one rapid test was developed. The assay was validated according to AOAC guidelines being able to detect ß-lactoglobulin (0.5 ppm), casein (2 ppm), whey and powder milk (1–5 ppm). No cross-reactivity was found with a panel of 38 food commodities. The method is a rapid and suitable tool to identify milk proteins in processed food, ingredients, and rinsing water

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

Evidence for inflows and outflows in the nearby black hole transient Swift J1727.8-162

We present 20 epochs of optical spectroscopy obtained with the GTC-10.4m telescope across the bright discovery outburst of the black hole candidate Swift J1727.8-162. The spectra cover the main accretion states and are characterised by the presence of hydrogen and helium emission lines, commonly observed in these objects. They show complex profiles, including double-peaks, but also blue-shifted absorptions (with blue-edge velocities of 1150 km/s), broad emission wings and flat-top profiles, which are usual signatures of accretion disc winds. Moreover, red-shifted absorptions accompanied by blue emission excesses suggest the presence of inflows in at least two epochs, although a disc origin cannot be ruled out. Using pre-outburst imaging from Pan-STARRS, we identify a candidate quiescent optical counterpart with a magnitude of g = 20.8. This implies an outburst optical amplitude of DV = 7.7, supporting an estimated orbital period of 7.6 h, which favours an early K-type companion star. Employing various empirical methods we derive a distance to the source of d = 2.7 +- 0.3 kpc, corresponding to a Galactic Plane elevation of z = 0.48 +- 0.05 kpc. Based on these findings, we propose that Swift J1727.8-162 is a nearby black hole X-ray transient that exhibited complex signatures of optical inflows and outflows throughout its discovery outburst.Comment: 4 Figures, 1 table. Appendix with 1 table. Accepted for publication in A&A Letters. Two typos in section 4.3 have been amended in the latest ArXiv version. Ar/AV =2.271 should be instead Ar/E(B-V) = 2.271. The Porb units in the equation should be in days (as in the original paper, Casares 2018). Neither of these actually affect any of the results of the pape

Development and validation of sensitive and rapid immunoassays to detect minute amounts of hazelnut in processed food and working surfaces

Hazelnut (Corylus avellana L.) represents one of the most allergenic nuts and it can be found as a hidden allergen in processed food due to cross contamination. Therefore, sensitive and specific analytical techniques are in high demand to be used in allergen risk management plans at food industry. In this study, sandwich ELISA and Lateral Flow Immunoassay (LFIA) to detect hazelnut have been developed based on the determination of Cor a 9, one of the most abundant and allergenic proteins of hazelnut. Results showed that cross-reactivity was only found with walnut and Pecan nut, which was lower than 0.1%. When analyzing food spiked with a hazelnut extract or blended with hazelnut flour, ELISA and LFIA were able to detect 0.1 ppm and 0.5 ppm of hazelnut protein with a recovery from 82 to 110%. ELISA and LFIA could also detect 0.15 and 0.6 ppm of hazelnut protein in baked cookies incurred with ground hazelnut, respectively. Furthermore, LFIA could detect 1.25 μg of hazelnut protein in working surfaces of stainless steel and melamine. The sandwich ELISA was in-house validated, showing acceptable results of precision. Likewise, ELISA and LFIA showed to be robust tests. The combined use of both assays could improve the allergen risk management plans in food industry to monitor the presence of hazelnut traces in raw ingredients, processed food and working surfaces