Zeitschriftenartikel: „Radula (plantes)“

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Bataw, Ali A., und Nesrin K. Shareef. „Foraging Behaviour of Honey Bees Apis mellifera Linn. Visiting The Flowers of Some Wild Plants in Eljabal Alakhder-Libya“. Al-Mukhtar Journal of Sciences 33, Nr. 2 (30.06.2018): 117–23. http://dx.doi.org/10.54172/mjsc.v33i2.175.

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This study was conducted to identify the foraging behaviour of honey bees Apis mellifera in the search for food during their visit to the wild flower plants Sinapis alba, Pelargonium radula, Malva parviflora and Stachy stournefortii in Eljabal Alakhder region. The results showed differences in the handling time periods with a significant difference between plant flower species. It showed a longer resting period compared with the handling time for flowers of the Pelargonium radula, which recorded the lowest time, also the travelling time of honey bee among the flowers of the plant species showed a significant difference. Stachy stournefortii recorded a longer travelling time with an average of 4.3 seconds, and Pelargonium radula with 3.5 seconds. Apis mellifera showed a different activity among the different flowers in the collection of nectar or pollen during different daytime hours.

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Söderström, Lars, Matt Renner, Anders Hagborg und Matt Von Konrat. „Notes on Early Land Plants Today. 50. Radula sainsburiana is a synonym of R. helix (Radulaceae, Marchantiophyta)“. Phytotaxa 162, Nr. 4 (17.03.2014): 239. http://dx.doi.org/10.11646/phytotaxa.162.4.9.

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Sosna, Ireneusz, und Daria Kortylewska. „Estimation of Interstock and Intermediate Stock Usefulness for Summer Pear Cvs. Budded on Two Rootstocks“. Journal of Horticultural Research 21, Nr. 1 (01.06.2013): 79–82. http://dx.doi.org/10.2478/johr-2013-0011.

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Abstract In order to increase the profitability of pear production, a greater density of weak growing trees per area unit should be planted. In Poland, the most frequently used pear dwarfing rootstocks are quince clones. The main disadvantage of them is a physiological incompatibility with some cultivars. The aim of this study was to evaluate the effect of the rootstock, interstock, and intermediate stock on growth and productivity of two summer pear cultivars, which are not compatible with the quince rootstock. Twoyear- old pear trees of ‘Radana’ and ‘Clapp’s Favourite’ cvs of different compositions were planted in the spring 2006. The following combinations were evaluated: ‘Radana’ and ‘Clapp’s Favourite’ on Caucasian pear seedlings, ‘Radana’ and ‘Clapp’s Favourite’ on quince SI with an intermediate stem piece of ’Doyenne du Comice’ and ‘Radana’ on Caucasian pear with ‘Pyrodwarf’ interstock. Up to the 6th year after planting, trees of ‘Radana’ grafted on Caucasian pear seedlings and on quince with intermediate stock yielded better than ‘Radana’ trees composed of Caucasian pear seedling and ‘Pyrodwarf’ interstock. ‘Clapp’s Favourite’ in all combinations had significantly heavier fruits. The highest crop efficiency index had ‘Radana’ on quince with ’Doyenne du Comice’ intermediate stock.

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Passos, J. L., R. M. S. A. Meira und L. C. A. Barbosa. „Foliar anatomy of the species Lantana camara and L. radula (Verbenaceae)“. Planta Daninha 27, Nr. 4 (2009): 689–700. http://dx.doi.org/10.1590/s0100-83582009000400007.

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The species Lantana camara, commonly used as ornamental, has spread worldwide becoming one of the world's most important weeds. To develop new methods of control of this plant, it is essential to distinguish it from other species of the same genus, and this is usually accomplished through taxonomic studies of fertile samples. Considering the similarity between L. camara and L. radula, and the consequent difficulty in distinguishing one from the other when only sterile samples are available, this work aimed to investigate the use of the anatomical characteristics of the leaves of both species as tools for supporting correct classification. The leaves of L. camara and L. radula were anatomically examined by light microscopy and scanning electron microscopy. The major differences were observed in the petiole, which presented secretory idioblasts in L. camara. Secretory idioblasts were observed in the leaf blades of L. camara and Crystalliferou idioblasts were found in L. radula. Glandular and nonglandular trichomes as well as the abaxial surface are different in each species. Such results can support the strategies aiming at the control of L. camara without interfering with L. radula.

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Mamontov, Yuriy S., Michael S. Ignatov, Dmitry V. Vasilenko, Andrei A. Legalov und Evgeny E. Perkovsky. „Hepatics from Rovno amber (Ukraine). 11. Radula oblongifolia and R. tikhomirovae sp. nov.“ Ecologica Montenegrina 72 (17.04.2024): 189–99. http://dx.doi.org/10.37828/em.2024.72.18.

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A study of Rovno amber has revealed two fossil leafy liverwort species of the genus Radula (Radulaceae, Marchantiophyta) that are new to the late Eocene flora of Rovno amber. One of these species, R. oblongifolia, was described previously from Eocene Baltic and Bitterfeld amber, whereas the other species, R. tikhomirovae, is described here as new. Radula tikhomirovae differs from R. oblongifolia and two other Eocene species of that genus, R. sphaerocarpoides and R. baltica, by the presence of microphyllous branches and by the shape of its leaf lobules.

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Roebuck, C. J., S. J. Siebert, J. M. Berner und J. Marcelo-Silva. „The Influence of Serpentine Soil on the Early Development of a Non-Serpentine African Thistle, Berkheya radula (Harv.) De Wild“. Plants 11, Nr. 18 (09.09.2022): 2360. http://dx.doi.org/10.3390/plants11182360.

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Serpentine soils are rich in heavy metals and poor in nutrients, limiting plant species’ performance and survival. Nevertheless, specificities of such limitations as well as adaptability features required for thriving in serpentine environments are barely known. The Barberton Greenstone Belt in South Africa is an example of an area containing serpentine soil with adapted vegetation. In this study, a pot experiment was performed to compare development features (i.e., germination rates, leaf count, leaf length, biomass and photosynthetic capacity) during the early development of the non-serpentine species Berkheya radula, a genus consisting of known metal hyperaccumulators from serpentine areas in South Africa. B. radula was grown in serpentine soils taken from the Barberton region. B. radula leaves had heavy metals in concentrations that confirmed the species as a phytoextractor. There were trends for enhanced productivity and photosynthesis in the serpentine treatments compared to the control. Leaf count, leaf length, electron transport efficiency (ψEo/(1 − ψEo), density of reaction centers and PIABS,total were significantly and positively correlated with at least one of the heavy metals in the leaves. Germination rates were positively influenced by K, whereas biomass and the density of reaction centers were negatively affected by Ca and P, and only Ca, respectively. The heavy metals Zn, Ni and Co were positively correlated with each other, whereas they were negatively correlated with the macronutrients K, Ca and P. The latter correlated positively with each other, confirming higher fertility of the control soil. Our study suggests that B. radula exhibits metallophyte characteristics (i.e., preadapted), despite not naturally occurring on metal-enriched soil, and this provides evidence that the potential for bioaccumulation and phytoremediation is shared between serpentine and non-serpentine species in this genus.

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Pócs, Tamás. „Contribution to the bryoflora of Australia, V. Radula tonitrua sp. nov. from Queensland“. Telopea 24 (05.05.2021): 189–201. http://dx.doi.org/10.7751/telopea14918.

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Study of two recognised geographic lineages within Radula novae-hollandiae sens. lat. have resulted in the detection of morphological differences between individuals from the Queensland Wet Tropics, and those from New South Wales. Individuals from the Wet Tropics have perianths that are shorter at maturity (1.6–2.0 v. 3.8–4.4 mm), leaf lobes that usually bear numerous marginal gemmae, and leaf-lobules that are smaller and more quadrate. The morphological differences, particularly in perianth length, were not fully appreciated previously and provide evidence supporting the recognition of the Queensland Wet Tropics lineage as a distinct and new species, Radula tonitrua, which is here described. The degree of phylogenetic divergence and fixed molecular difference between R. tonitrua and R. novae-hollandiae, are comparable with the separation observed between R. ocellata and R. pulchella, another species pair exhibiting the same geographic disjunction.

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Kodym, Andrea, Ian Clarke, Cristina Aponte, Shane Turner, Eric Bunn und John Delpratt. „Large-scale micropropagation of the Australian key species Gahnia radula (Cyperaceae) and its return to revegetation sites“. Australian Journal of Botany 62, Nr. 5 (2014): 417. http://dx.doi.org/10.1071/bt14091.

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We report on the successful propagation of the sedge Gahnia radula (R.Br.) Benth. from seed by using plant tissue culture, and its successful establishment in the field. This keystone species, although common along parts of the eastern coast of Australia, is currently not available for revegetation because of a lack of efficient propagation methods, leading to the use of substitute species in many restoration programs. Even though seed quality is a common problem for G. radula, one population bearing filled seed was located in the near-east of Melbourne and after harvest of fruit in December 2011, seeds were successfully germinated in vitro after removal of the pericarp. Overnight soaking in sterile 10% (v/v) smoke water before culturing enhanced in vitro germination from 29.2% to 66.7%. In vitro-grown seedlings were then used as starting material for tissue-culture propagation via shoot culture. A micropropagation rate of about six new plantlets per cycle was achieved within 5–6 weeks with liquid half-strength Murashige–Skoog medium and a pulse treatment with 10 µM 6-benzylaminopurine (BAP) and 2 µM naphthalene acetic acid (NAA). Plants rooted after receiving a pulse treatment with 5 µM kinetin and were successfully acclimatised into potting mix and were ready for field planting after 5–6 months. Tube stock was planted into two field sites with minimal weed control. Survival was 98% in both cases 1 month after planting and 54% and 74% after the summer. Division of in vitro-derived plants in the nursery was very successful, with 93–96% establishment of divisions. This research highlights the important role of plant tissue culture in conserving biodiversity of native flora.

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Rezende, Denise V., und José C. Dianese. „Revisão taxonômica de algumas espécies de Ravenelia em leguminosas do Cerrado brasileiro“. Fitopatologia Brasileira 28, Nr. 1 (Januar 2003): 27–36. http://dx.doi.org/10.1590/s0100-41582003000100004.

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Oito espécies de Ravenelia descritas anteriormente foram revisadas e acrescentadas ilustrações inéditas das características morfológicas de alguns desses fungos causadores de ferrugem em Leguminosae. As espécies de Ravenelia estudadas foram: Ravenelia bezerrae sobre Enterolobium ellipticum ; R. densifera sobre Senna silvestris; R. dieteliana sobre Calliandra dysantha. var. dysantha; R. geminipora sobre Platymenia reticulata; R. lonchocarpi sobre Lonchocarpus campestris; R. mimosae-sensitivae sobre Mimosa radula var. imbricata; R. pileolarioides sobre Caesalpinia pyramydales e R. santos-costae, sobre Calliandra dysantha.

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Assis, Marta Camargo de. „ALSTROEMERIACEAE NO ESTADO DO RIO DE JANEIRO“. Rodriguésia 55, Nr. 85 (Juli 2004): 5–15. http://dx.doi.org/10.1590/2175-78602004558501.

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RESUMO Neste trabalho são apresentadas as espécies de Alstroemeriaceae do estado do Rio de Janeiro, Brasil. A família e representada na área pelo gênero Alstroemeria, incluindo cinco espécies: A. caryophyllaea Jacq., A. cunha Vell., A. foliosa Mart. ex Schult. & Schult. f., A. isabelleana Herb., A. radula Dusén e pelo gênero Bomarea incluindo apenas a especie B. edulis (Tussac) Herb. Novas sinonimizações, chaves de identificação, descriçãoao das espécies, ilustrações e comentários são aqui apresentados.

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Sosna, Ireneusz Stefan. „Effect of condit soil improver on growth, yield and leaf mineral content of two summer pear cvs. with interstocks“. Acta Scientiarum Polonorum Hortorum Cultus 20, Nr. 6 (09.12.2021): 83–92. http://dx.doi.org/10.24326/asphc.2021.6.9.

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The study involving 2 pear cultivars was conducted in 2006–2016. ‘Radana’ and ‘Clapp’s Favourite’ were planted in the spring 2006 in the Experimental Station next to Wrocław (south-western Poland) on Quince S1 and Caucasian pear seedlings with 2 interstocks – ‘Doyenne du Comice’ and ‘Pyrodwarf’. An annual dose of 3 tonnes per hectare of Condit Basic bio-fertilizer was applied onto the tree row soil surface at the beginning of March 2012, i.e., starting from the 7th year after the planting. The study objective was to evaluate effect of Condit preparation on summer pear tree cultivars which are not compatible with Quince, and to assess interstock suitability in their context. The yields obtained in the first eleven years following tree planting were the most abundant for ‘Radana’ on Caucasian pear and on Quince with ‘Doyenne du Comice’ interstock. When applied for 5 years, Condit increased the leaf surface area, however a significant difference was exhibited only by ‘Radana’ on the Caucasian pear. This soil improver did not affect tree growth and yielding; total chlorophyll content; foliar Mg, P, Ca, and K; and mean fruit mass across the investigated treatment combinations.

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LEPŠÍ, MARTIN, PETR LEPŠÍ, MICHAEL HOHLA und GERGELY KIRÁLY. „Rubus lentianus, a new species from Austria and Germany—another piece of the puzzle from a European hotspot of Rubus series Radula“. Phytotaxa 594, Nr. 1 (24.04.2023): 43–52. http://dx.doi.org/10.11646/phytotaxa.594.1.2.

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A new nemophilous tetraploid bramble species, Rubus lentianus of the series Radula, occurring in Central Europe (Upper Austria and Lower Bavaria), is described. Deeply incised terminal leaflets of primocane leaves and a long, abruptly narrowing apex separate it from species of this series. An identification key, a distribution map, a list of revised specimens, a scan of the type specimen, pen drawings and photographs of living specimens are provided.

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Naves, Guilherme de Faria Silva, Vinícius Coelho Kuster, Mariana Machado, Patrícia Dias Santos, Vitor Campana Martini und Denis Coelho Oliveira. „Metabolite investments and stress levels among tissue compartments of Palaeomystella olygophaga (Lepidoptera) galls on Macairea radula (Melastomataceae)“. Australian Journal of Botany 69, Nr. 3 (2021): 131. http://dx.doi.org/10.1071/bt20128.

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Galling insects manipulate host plant tissues for their own benefit. Because of feeding activity of the gall insects, both structural and metabolic changes occur in the host plant, leading to the formation of an abnormal growth of new organ (the gall). Galls induced by Palaeomystella oligophaga (Lepidoptera) on Macairea radula (Melastomataceae) depend on the constant larval feeding stimulus for establishment and development. The gall consists of two tissue compartments – the storage and nutritive tissues. These two gall tissues were investigated here in terms of the levels of oxidative stress and of a possible differential chemical investment. In addition, we investigated the relationship between gall coloration and the concentration of primary metabolites. Our results supported a differential investment of chemical compounds in the M. radula compartments, with higher concentrations of polysaccharides, malondialdehyde, and phenolic compounds in the storage tissue, and higher total soluble sugar concentrations in the nutritive tissue. Regarding gall colour, conflicting results were observed in the present gall system. Water-soluble polysaccharides were detected at higher concentrations in red galls than in green galls. As a water-soluble polysaccharide, pectin seems to be related to increased anthocyanin stability, a process that might occur in galls, leading to red coloration.

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Kane, Stephen R., und Kaspar von Braun. „Transit Detection of Radial Velocity Planets“. Proceedings of the International Astronomical Union 4, S253 (Mai 2008): 358–61. http://dx.doi.org/10.1017/s1743921308026641.

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AbstractThe orbital parameters of extra-solar planets have a significant impact on the probability that the planet will transit the host star. This was recently demonstrated by the transit detection of HD 17156b whose favourable eccentricity and argument of periastron dramatically increased its transit likelihood. We present a study which provides a quantitative analysis of how these two orbital parameters affect the geometric transit probability as a function of period. Further, we apply these results to known radial velocity planets and show that there are unexpectedly high transit probabilities for planets at relatively long periods. For a photometric monitoring campaign which aims to determine if the planet indeed transits, we calculate the significance of a null result and the subsequent constraints that may be applied to orbital parameters.

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Pócs, T., J. G. Graham, M. von Konrat und J. Larraín. „New liverwort records from the Peruvian Andes“. Acta Botanica Hungarica 64, Nr. 1-2 (21.04.2022): 187–200. http://dx.doi.org/10.1556/034.64.2022.1-2.10.

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Enumeration and distributional data of 28 liverworts new to Peru are presented, accompanied by taxonomic annotations, phytogeographical evaluation and illustrations. Remarkable new Peruvian records include the very rare northern Andean endemic Platycaulis renifolia as well as Frullania pearceana, hitherto known only from its type locality in Bolivia. Oil bodies are described for the first time in the genus Platycaulis and male branches are newly observed in Radula yanoella, a species hitherto known only in sterile state.

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FRAGA, CLAUDIO NICOLETTI DE, und PAULO JOSÉ FERNANDES GUIMARÃES. „Two new species of Pleroma (Melastomataceae) from Espírito Santo, Brazil“. Phytotaxa 166, Nr. 1 (17.04.2014): 77. http://dx.doi.org/10.11646/phytotaxa.166.1.5.

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Pleroma marinana and P. penduliflora, two new species of Pleroma (Melastomataceae) from the dry seasonal Atlantic forest of Espírito Santo, Brazil, are described and illustrated, with their affinities and diagnostic characters discussed. Pleroma marinana is similar to Tibouchina radula and T. oreophila while Pleroma penduliflora is similar to Pleroma heteromalla, Tibouchina bahiensis and T. formosa. According to the criteria of the IUCN Red List, T. marinana must be included in the vulnerable and T. penduliflora in the endangered category.

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Sato, Bun'ei. „Radial-Velocity Searches for Exoplanets in East Asia“. Proceedings of the International Astronomical Union 8, S293 (August 2012): 1–9. http://dx.doi.org/10.1017/s1743921313012441.

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AbstractHundreds of extrasolar planets have been discovered around various types of stars by various techniques during the past decade. Among them precise radial velocity measurements for stars are fundamental technique to detect and confirm exoplanets. In this paper activities in East-Asian region in this research field are introduced: East-Asian Planet Search Network, which is a network searching for planets around evolved intermediate-mass stars, and Subaru/IRD project, which will search for habitable planets around M-type dwarfs using infrared radial-velocity method.

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Pócs, Tamás, Haji Mohamed, Kien-Thai Yong und Yih-Horng Cheah. „Data to the Malaysian liverwort flora, I“. Polish Botanical Journal 59, Nr. 2 (01.12.2014): 215–20. http://dx.doi.org/10.2478/pbj-2014-0042.

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Abstract 120 liverwort specimens collected in peninsular Malaysia for oil body studies belonged to 80 species, 6 of which (Frullania subocellata S. Hatt., Chiloscyphus integerrimus Schiffn., Bazzania assamica (Steph.) S. Hatt., Bazzania bilobata Kitag., Telaranea quadriseta (Steph.) J. Engel & G. L. Merrill and Radula assamica Steph.) proved to be new for Malaysia and 9 to its peninsular part or to Selangor or Pahang states. The most interesting occurrences were of Frullania subocellata, hitherto known only from Seram Island, Chiloscyphus integerrimus, known from Java, and Telaranea quadriseta, an Australian element. The majority of the collected species are of Indomalesian distribution. Microphotos and distribution maps of the more interesting species are provided.

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Luque, R., T. Trifonov, S. Reffert, A. Quirrenbach, M. H. Lee, S. Albrecht, M. Fredslund Andersen et al. „Precise radial velocities of giant stars“. Astronomy & Astrophysics 631 (November 2019): A136. http://dx.doi.org/10.1051/0004-6361/201936464.

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We report the discovery of a second planet orbiting the K giant star 7 CMa based on 166 high-precision radial velocities obtained with Lick, HARPS, UCLES, and SONG. The periodogram analysis reveals two periodic signals of approximately 745 and 980 d, associated with planetary companions. A double-Keplerian orbital fit of the data reveals two Jupiter-like planets with minimum masses mb sini ~ 1.9 MJ and mc sini ~ 0.9 MJ, orbiting at semimajor axes of ab ~ 1.75 au and ac ~ 2.15 au, respectively. Given the small orbital separation and the large minimum masses of the planets, close encounters may occur within the time baseline of the observations; thus, a more accurate N-body dynamical modeling of the available data is performed. The dynamical best-fit solution leads to collision of the planets and we explore the long-term stable configuration of the system in a Bayesian framework, confirming that 13% of the posterior samples are stable for at least 10 Myr. The result from the stability analysis indicates that the two planets are trapped in a low-eccentricity 4:3 mean motion resonance. This is only the third discovered system to be inside a 4:3 resonance, making this discovery very valuable for planet formation and orbital evolution models.

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Fang, Wenlong. „Comparisons of Detection Paradigm of Planet: Transit and Radial Velocity“. Highlights in Science, Engineering and Technology 38 (16.03.2023): 226–34. http://dx.doi.org/10.54097/hset.v38i.5811.

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The transit and radial velocity method are two most widely used approach in exoplanet detection. This paper compares the advantages and disadvantages of two methods based on the characteristics of planets they found and different calculation results. Different distribution of parameters brings the preference for two methods. In detail, the radial velocity method discovered more gigantic planets while still have most planets with smaller size like that of the transit method. The minimum and maximum of orbital period are all relatively lower for transit method. Significant difference in the composition of planets found by two method occurs when combining mass and radius to compare density distribution. More Super-Earth planets seem to appear in transit data compared to radial velocity method in the same radius range. These patterns are closely related to the characteristics of observation condition. The various data processing method also affects the resulting parameters. This paper attempts to reach the calculation for transit and radial velocity method with basic fitting models, which will be compared with calculations of the same planets from previous researches. These results shed light on guiding further exploration of planet detections.

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Yang, Tianlin. „Transit and radial velocity method for exoplanet detection“. Theoretical and Natural Science 10, Nr. 1 (17.11.2023): 137–42. http://dx.doi.org/10.54254/2753-8818/10/20230329.

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This article introduces some basic methods that human usually uses nowadays to detect exoplanets, including transits method, radial velocity method, direct imaging method, gravitational microlensing method, and astrometry method. As we all know, none of these methods are perfect, each of them has its advantages: some of them are good at detecting planets with great mass, some are good at detecting planets with great radius, and some of the methods are good at detecting planets far away from their host star. But at the same time, each method has its own disadvantages. That is the reason why sometimes some of these methods are used together to get information about specific exoplanets. This chapter will introduce these methods by giving information on how these methods work, the equipment each of them requires, the advantages and limitations of these methods, and the history and development of these methods. Finally, there is a conclusion that states the characteristics of the planets each method is good at detecting.

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OCUPA-HORNA, LUIS, MARK WILSON und MARCO M. JIMÉNEZ. „A new species of Pleurothallis (Orchidaceae: Pleurothallidinae) in subsection Macrophyllae-Fasciculatae found in Carpish Montane Forest Regional Conservation Area, Peru“. Phytotaxa 629, Nr. 2 (06.12.2023): 163–75. http://dx.doi.org/10.11646/phytotaxa.629.2.6.

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A new species of Pleurothallis belonging to subsection Macrophyllae-Fasciculatae was discovered in the Carpish Montane Forest Regional Conservation Area, Huánuco, Peru. Pleurothallis carpishensis is described, illustrated, and compared to P. radula, from which it is differentiated by the flowers borne from a depressed spathaceous bract resting on a navicular concavity on the leaf, the oblong-lanceolate, apiculate petals, with large papillae on the margins, the triangular, subacute lip, with a basal, widely ovate and emarginate, papillose-verrucose callus, with two oblique, lateral and marginal keels.

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Döbbeler, Peter. „Ascomycetes on the epiphyllous Radula flaccida (Hepaticae)“. Nova Hedwigia 66, Nr. 3-4 (19.05.1998): 325–73. http://dx.doi.org/10.1127/nova.hedwigia/66/1998/325.

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Kornet, K., und S. Wolf. „Radial distribution of planets“. Astronomy & Astrophysics 454, Nr. 3 (17.07.2006): 989–95. http://dx.doi.org/10.1051/0004-6361:20053895.

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Haywood, R. D., A. Collier Cameron, D. Queloz, S. C. C. Barros, M. Deleuil, R. Fares, M. Gillon et al. „Disentangling planetary orbits from stellar activity in radial-velocity surveys“. International Journal of Astrobiology 13, Nr. 2 (14.01.2014): 155–57. http://dx.doi.org/10.1017/s147355041300044x.

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AbstractThe majority of extra-solar planets have been discovered (or confirmed after follow-up) through radial-velocity (RV) surveys. Using ground-based spectrographs such as High Accuracy Radial Velocity Planetary Search (HARPS) and HARPS-North, it is now possible to detect planets that are only a few times the mass of the Earth. However, the presence of dark spots on the stellar surface produces RV signals that are very similar in amplitude to those caused by orbiting low-mass planets. Disentangling these signals has thus become the biggest challenge in the detection of Earth-mass planets using RV surveys. To do so, we use the star's lightcurve to model the RV variations produced by spots. Here we present this method and show the results of its application to CoRoT-7.

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Baluev, Roman V. „Several problems of exoplanetary orbits determination from radial velocity observations“. Proceedings of the International Astronomical Union 3, S249 (Oktober 2007): 101–10. http://dx.doi.org/10.1017/s1743921308016463.

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AbstractExisting algorithms of analysis of radial velocity time series are improved for the purposes of extrasolar planets detection and characterizing. Three important effects are considered: the poorly known radial velocity jitter, periodic systematic errors, and statistical bias due to non-linearity of models. Mathematical tools to account for these effects are developed and applied to a number of real planetary systems. In particular, it is shown that two outer planets of HD37124 are likely trapped in the 2/1 resonance. The dwarf star GJ876 may host an extra, Neptune-mass, planet which is in resonance with two giant planets in this system.

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Yoshihara, Hiroshi, und Makoto Maruta. „Shear moduli in the longitudinal-radial and radial-tangential planes of Sitka spruce measured by torsional vibration tests“. Holzforschung 72, Nr. 6 (27.06.2018): 507–12. http://dx.doi.org/10.1515/hf-2017-0136.

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AbstractThe shear moduli (SM) of solid wood in the longitudinal-radial (LR) and radial-tangential (RT) planes of Sitka spruce are extremely different from each other and were obtained via a torsional vibration (TV) test by varying the aspect ratios and conducting subsequent numerical analyses. The SM in both planes were accurate, when the aspect ratios of the specimens were appropriately selected, even though the SM around the torsional axis were extremely different from each other.

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Klein, Baptiste, und J.-F. Donati. „Simulating radial velocity observations of trappist-1 with SPIRou“. Monthly Notices of the Royal Astronomical Society 488, Nr. 4 (15.07.2019): 5114–26. http://dx.doi.org/10.1093/mnras/stz1953.

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ABSTRACT We simulate a radial velocity (RV) follow-up of the TRAPPIST-1 system, a faithful representative of M dwarfs hosting transiting Earth-sized exoplanets to be observed with SPIRou in the months to come. We generate an RV curve containing the signature of the seven transiting TRAPPIST-1 planets and a realistic stellar activity curve statistically compatible with the light curve obtained with the K2 mission. We find a ±5 m s−1 stellar activity signal comparable in amplitude with the planet signal. Using various sampling schemes and white noise levels, we create time-series from which we estimate the masses of the seven planets. We find that the precision on the mass estimates is dominated by (i) the white noise level for planets c, f, and e and (ii) the stellar activity signal for planets b, d, and h. In particular, the activity signal completely outshines the RV signatures of planets d and h that remain undetected regardless of the RV curve sampling and level of white noise in the data set. We find that an RV follow-up of TRAPPIST-1 using SPIRou alone would likely result in an insufficient coverage of the rapidly evolving activity signal of the star, especially with bright-time observations only, making statistical methods such as Gaussian Process Regression hardly capable of firmly detecting planet f and accurately recovering the mass of planet g. In contrast, we show that using bi-site observations with good longitudinal complementary would allow for a more accurate filtering of the stellar activity RV signal.

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Filho, José G. Sena, Haroudo S. Xavier, José M. Barbosa Filho und Jennifer M. Duringer. „A Chemical Marker Proposal for the Lantana genus: Composition of the Essential Oils from the Leaves of Lantana radula and L. canescens“. Natural Product Communications 5, Nr. 4 (April 2010): 1934578X1000500. http://dx.doi.org/10.1177/1934578x1000500429.

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Essential oil extracts from the leaves of two Lantana species ( L. radula Sw. and L. canescens Kunth), for which no prior analysis has been reported, were analyzed by GC-MS. This information was utilized to propose chemical markers for Lantana species so that identification between physically similar plant species can be achieved through chemical analysis. Results showed 33 constituents for L. canescens, among which β-caryophyllene (43.9%), β-cubebene (10.1%), elixene (8.6%), β-phellandrene (6.1%), α-caryophyllene (2.6%) and dehydro-aromadendrene (2.6%) were the principle components. L. radula revealed the presence of 21 compounds, the most abundant of which were β-cubebene (31.0%), β-caryophyllene (20.8%), elixene (10.0%), α-salinene (6.4%), β-phellandrene (6.1%), copaene (4.9%) cadinene (1.4%) and psi-limonene (1.4%). The high concentration of β-caryophyllene in the samples tested here and those in the literature make it a good candidate for a chemical marker for Lantana species, with β-cubebene, elixene and β-phellandrene following as minor compounds identified more sporadically in this genus. On the other hand, Lippia species, which are morphologically similar to those from the Lantana genus, would contain limonene, citral, carvacrol, β-myrcene, camphor and thymol as the main chemical markers. These chemical markers would be a powerful tool for maintaining quality control in the extraction of essential oils for use in medicinal applications, as well as in identification of plant specimens to a taxonomist.

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Oliveira-Da-Silva, Fúvio Rubens, und Anna Luiza Ilkiu-Borges. „On a new species of Radula Dumort. (Radulaceae, Machantiophyta) from mountain ranges in the Atlantic Forest, Brazil“. Nova Hedwigia 110, Nr. 3 (01.05.2020): 287–92. http://dx.doi.org/10.1127/nova_hedwigia/2020/0580.

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Radula yamadae, a species from mountain ranges in the Atlantic forest, is described here as new to science. The new species is characterized by plants occasionally epiphyllous, densely branched, leaf lobes imbricate, ovate, apex obtuse to subacute, cell walls thin, trigones small, lobules distant to contiguous, rarely imbricate, subquadrate, 1/2–2/5 the lobe length, base rounded to obtuse, covering 1/3 to overlapping the stem, keel conspicuously convex, strongly inflated at rhizoid area and along the keel, and rhizoids numerous. A complete description and illustration of the new taxon as well as comments on morphology, taxonomy, and distribution are provided.

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Jaramillo, M. Alejandra. „Piper alwynii (Piperaceae), a New Species from the Cordillera del Cóndor at the Border of Peru and Ecuador“. Novon, A Journal for Botanical Nomenclature 31 (23.10.2023): 255–61. http://dx.doi.org/10.3417/2023862.

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Piper alwynii M. A. Jaram. (Piperaceae), a new species occurring in sandstone outcrops of the Cordillera del Cóndor at the border of Ecuador and Peru, is here described and illustrated. Morphologically it shows similarities to species in the Radula clade. Piper alwynii is similar to P. purdiei C. DC. but differs in having leaves pinnately nerved within the lower two thirds of the midvein, nerves pubescent on the abaxial surface, villous peduncles, and spikes 2–2.7 cm long. An identification key for 32 northern South American Piper L. species with small (≤ 10 cm) leaves is presented.

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Pinto, Marcelo Tala, Sabine Reffert, Andreas Quirrenbach, Stephan Stock, Trifon Trifonov und David S. Mitchell. „Precise radial velocities of giant stars“. Astronomy & Astrophysics 644 (24.11.2020): A1. http://dx.doi.org/10.1051/0004-6361/202038285.

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Context. More than 100 exoplanets have been discovered around K and G giant stars, and their properties differ considerably from those of the planets found orbiting Sun-like and late-type main-sequence stars. This allows us to study the properties of planetary systems after the host star has evolved off the main-sequence, and it helps us to constrain planetary formation and evolution models. Aims. Our aim is to find out whether the long-period radial velocity variations observed in four giant stars of the Lick survey are caused by orbiting planets, and to study the properties of the planet population as a function of the stellar evolutionary stage. Methods. We analyzed 12 yr of precise radial velocity data for four stars of the Lick sample. In addition, we compared the planet frequency as a function of the evolutionary stage for two surveys, Lick and Express, based on the evolutionary stages derived using Bayesian inference. Results. We report the discovery of two new exoplanets and three exoplanet candidates orbiting giant stars. The best Keplerian fits to the data yield minimum masses of 2.5 MJ and 4.3 MJ for the planets orbiting HD 25723 and 17 Sco, respectively. The minimum masses of an additional candidate around HD 25723, and of planet candidates around 3 Cnc and 44 UMa, would be 1.3 MJ, 20.7 MJ, and 12.1 MJ, respectively. In addition, we compute planet frequencies for the Lick and Express samples as a function of the evolutionary stage. Within each sample, the planet frequency for the horizontal branch stars is the same as for the red giant branch stars. Conclusions. We have discovered two new exoplanets and three new exoplanet candidates, one of them being the second planet in a possible multi-planetary system. Based on our derived planet frequencies, we conclude that stellar evolution does not affect the number of observable planets between the red-giant and horizontal-branch evolutionary stages.

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Santerne, Alexandre, Claire Moutou und François Bouchy. „Resolving blended radial velocities“. Proceedings of the International Astronomical Union 6, S276 (Oktober 2010): 549–50. http://dx.doi.org/10.1017/s174392131102117x.

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AbstractIn space, photometric surveys are very efficient to detect small transiting planets or stars which are contaminated by blended eclipsing binaries. We present some simulations compared to radial velocity (RV) observations obtained with the SOPHIE spectrograph (OHP, France) in order to determine the true nature of a brown dwarf candidate revealed by CoRoT: a background eclipsing binary diluted by a foreground star.

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Lagrange, A. M., P. Rubini, M. Nowak, S. Lacour, A. Grandjean, A. Boccaletti, M. Langlois et al. „Unveiling the β Pictoris system, coupling high contrast imaging, interferometric, and radial velocity data“. Astronomy & Astrophysics 642 (Oktober 2020): A18. http://dx.doi.org/10.1051/0004-6361/202038823.

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Context. The nearby and young β Pictoris system hosts a well resolved disk, a directly imaged massive giant planet orbiting at ≃9 au, as well as an inner planet orbiting at ≃2.7 au, which was recently detected through radial velocity (RV). As such, it offers several unique opportunities for detailed studies of planetary system formation and early evolution. Aims. We aim to further constrain the orbital and physical properties of β Pictoris b and c using a combination of high contrast imaging, long base-line interferometry, and RV data. We also predict the closest approaches or the transit times of both planets, and we constrain the presence of additional planets in the system. Methods. We obtained six additional epochs of SPHERE data, six additional epochs of GRAVITY data, and five additional epochs of RV data. We combined these various types of data in a single Markov-chain Monte Carlo analysis to constrain the orbital parameters and masses of the two planets simultaneously. The analysis takes into account the gravitational influence of both planets on the star and hence their relative astrometry. Secondly, we used the RV and high contrast imaging data to derive the probabilities of presence of additional planets throughout the disk, and we tested the impact of absolute astrometry. Results. The orbital properties of both planets are constrained with a semi-major axis of 9.8 ± 0.4 au and 2.7 ± 0.02 au for b and c, respectively, and eccentricities of 0.09 ± 0.1 and 0.27 ± 0.07, assuming the HIPPARCOS distance. We note that despite these low fitting error bars, the eccentricity of β Pictoris c might still be over-estimated. If no prior is provided on the mass of β Pictoris b, we obtain a very low value that is inconsistent with what is derived from brightness-mass models. When we set an evolutionary model motivated prior to the mass of β Pictoris b, we find a solution in the 10–11 MJup range. Conversely, β Pictoris c’s mass is well constrained, at 7.8 ± 0.4 MJup, assuming both planets are on coplanar orbits. These values depend on the assumptions on the distance of the β Pictoris system. The absolute astrometry HIPPARCOS-Gaia data are consistent with the solutions presented here at the 2σ level, but these solutions are fully driven by the relative astrometry plus RV data. Finally, we derive unprecedented limits on the presence of additional planets in the disk. We can now exclude the presence of planets that are more massive than about 2.5 MJup closer than 3 au, and more massive than 3.5 MJup between 3 and 7.5 au. Beyond 7.5 au, we exclude the presence of planets that are more massive than 1–2 MJup. Conclusions. Combining relative astrometry and RVs allows one to precisely constrain the orbital parameters of both planets and to give lower limits to potential additional planets throughout the disk. The mass of β Pictoris c is also well constrained, while additional RV data with appropriate observing strategies are required to properly constrain the mass of β Pictoris b.

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Weiss, Lauren M., Howard Isaacson, Andrew W. Howard, Benjamin J. Fulton, Erik A. Petigura, Daniel Fabrycky, Daniel Jontof-Hutter et al. „The Kepler Giant Planet Search. I. A Decade of Kepler Planet-host Radial Velocities from W. M. Keck Observatory“. Astrophysical Journal Supplement Series 270, Nr. 1 (27.12.2023): 8. http://dx.doi.org/10.3847/1538-4365/ad0cab.

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Abstract Despite the importance of Jupiter and Saturn to Earth’s formation and habitability, there has not yet been a comprehensive observational study of how giant exoplanets correlate with the architectural properties of close-in, sub-Neptune-sized exoplanets. This is largely because transit surveys are particularly insensitive to planets at orbital separations ≳1 au, and so their census of Jupiter-like planets is incomplete, inhibiting our study of the relationship between Jupiter-like planets and the small planets that do transit. To investigate the relationship between close-in, small and distant, giant planets, we conducted the Kepler Giant Planet Survey (KGPS). Using the W. M. Keck Observatory High Resolution Echelle Spectrometer, we spent over a decade collecting 2844 radial velocities (RVs; 2167 of which are presented here for the first time) of 63 Sunlike stars that host 157 transiting planets. We had no prior knowledge of which systems would contain giant planets beyond 1 au, making this survey unbiased with respect to previously detected Jovians. We announce RV-detected companions to 20 stars from our sample. These include 13 Jovians ( 0.3 M J < M sin i < 13 M J , 1 au < a < 10 au), eight nontransiting sub-Saturns, and three stellar-mass companions. We also present updated masses and densities of 84 transiting planets. The KGPS project leverages one of the longest-running and most data-rich collections of RVs of the NASA Kepler systems yet, and it will provide a basis for addressing whether giant planets help or hinder the growth of sub-Neptune-sized and terrestrial planets. Future KGPS papers will examine the relationship between small, transiting planets and their long-period companions.

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Renner, Matt A. M. Braggins. „Systematically relevant characters of the Radula sporophyte (Radulaceae: Hepaticae)“. Nova Hedwigia 81, Nr. 3-4 (01.11.2005): 271–300. http://dx.doi.org/10.1127/0029-5035/2005/0081-0271.

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Zhu, Wei. „The Intrinsic Multiplicity Distribution of Exoplanets Revealed from the Radial Velocity Method“. Astronomical Journal 164, Nr. 1 (13.06.2022): 5. http://dx.doi.org/10.3847/1538-3881/ac6f59.

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Abstract Planet multiplicities are useful in constraining the formation and evolution of planetary systems, but they are usually difficult to constrain observationally. Here, we develop a general method that can properly take into account the survey incompleteness and recover the intrinsic planet multiplicity distribution. We then apply it to the radial velocity (RV) planet sample from the California Legacy Survey (CLS). Within the 1 au (10 au) region, we find 21% ± 4% (19.2% ± 2.8%) of Sun-like stars host planets with masses above 10 M ⊕ (0.3 M J), about 30% (40%) of which are multiplanet systems; in terms of the RV semi-amplitude K, 33% ± 7% (25% ± 3%) of Sun-like stars contain planets of K > 1 m s−1 (3 m s−1), and each system hosts on average 1.8 ± 0.4 (1.63 ± 0.16) planets. We note that the hot Jupiter rate in the CLS Sun-like sample is higher than the consensus value of ∼1% by a factor of about three. We also confirm previous studies on the correlation between inner ( <1 au) and outer ( >1 au) planets.

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Udry, Stephane, Guillermo Torres, Birgitta Nordström, Francis C. Fekel, Kenneth C. Freeman, Elena V. Glushkova, Geoffrey W. Marcy et al. „COMMISSION 30: RADIAL VELOCITIES“. Proceedings of the International Astronomical Union 4, T27A (Dezember 2008): 316–25. http://dx.doi.org/10.1017/s1743921308025763.

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This three-year period has seen considerable activity in the Commission, with a wide range of applications of radial velocities as well as a significant push toward higher precision. The latter has been driven in large part by the exciting research on extrasolar planets. This field is now on the verge of detecting Earth-mass bodies around nearby stars, as demonstrated by recent work summarized below, and radial velocities continue to play a central role.

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Hirano, Teruyuki, Bun'ei Sato, Kento Masuda, Othman Michel Benomar, Yoichi Takeda, Masashi Omiya und Hiroki Harakawa. „Search for Close-in Planets around Evolved Stars with Phase-curve variations and Radial Velocity Measurements“. Proceedings of the International Astronomical Union 11, A29A (August 2015): 63–64. http://dx.doi.org/10.1017/s1743921316002404.

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AbstractTidal interactions are a key process to understand the evolution history of close-in exoplanets. But tidals still have a large uncertainty in their prediction for the damping timescales of stellar obliquity and semi-major axis. We have worked on a search for transiting giant planets around evolved stars, for which few close-in planets were discovered. It has been reported that evolved stars lack close-in planets, which is often attributed to the tidal evolution and/or engulfment of close-in planets by the hosts. Meanwhile, Kepler has detected a certain fraction of transiting planet candidates around evolved stars. Confirming the planetary nature for these candidates is especially important since the comparison between the occurrence rates of close-in planets around main sequence stars and evolved stars provides a unique opportunity to discuss the final stage of close-in planets. With the aim of confirming KOI planet candidates around evolved stars, we measured precision radial velocities (RVs) for evolved stars with transiting planet candidates using Subaru/HDS. We also developed a new code which simultaneously models and fits the observed RVs and phase-curve variations in the Kepler data (e.g., transits, stellar ellipsoidal variations, and planet emission/reflected light). As a result of applying the global fit to KOI giants/subgiants, we confirmed two giant planets around evolved stars (Kepler-91 and KOI-1894), as well as revealed that KOI-977 is more likely a false positive.

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Cruzado-Tafur, Edith, Katarzyna Bierla, Lisard Torró und Joanna Szpunar. „Accumulation of As, Ag, Cd, Cu, Pb, and Zn by Native Plants Growing in Soils Contaminated by Mining Environmental Liabilities in the Peruvian Andes“. Plants 10, Nr. 2 (27.01.2021): 241. http://dx.doi.org/10.3390/plants10020241.

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The capability of native plant species grown in polluted post-mining soils to accumulate metals was evaluated in view of their possible suitability for phytoremediation. The study areas included two environmental liabilities in the Cajamarca region in the Peruvian Andes. The content of As, Ag, Cd, Cu, Pb, and Zn was determined in individual plant organs and correlated with soil characteristics. The degree of the pollution depended on the metal with results ranging from uncontaminated (Cd) to moderately (Zn), strongly (As, Cu), and extremely contaminated (Pb, Ag) soils. The metals were mainly present in the fractions with limited metal mobility. The bioaccumulation of the metals in plants as well the translocation into overground organs was determined. Out of the 21 plants evaluated, Pernettya prostrata and Gaultheria glomerate were suitable for Zn, and Gaultheria glomerata and Festuca sp. for Cd, phytostabilization. The native species applicable for Cd phytoremediation were Ageratina glechonophylla, Bejaria sp., whereas Pernettya prostrata Achyrocline alata,Ageratina fastigiate, Baccharis alnifolia, Calceolaria tetragona, Arenaria digyna, Hypericum laricifolium, Brachyotum radula, and Nicotiana thyrsiflora were suitable for both Cd and Zn. None of the studied plants appeared to be suitable for phytoremediation of Pb, Cu, As and Ag.

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Rogers, Leslie A. „Combining Transit and Radial Velocity Data“. Proceedings of the International Astronomical Union 11, A29A (August 2015): 214–16. http://dx.doi.org/10.1017/s1743921316002866.

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AbstractThe Kepler Mission, combined with ground based radial velocity (RV) follow-up, has revolutionized the observational constraints on sub-Neptune-size planet compositions. Kepler's unprecedentedly large and homogeneous samples of planets with both mass and radius constraints open the possibility of statistical studies of the underlying planet composition distribution. This presentation describes the application of hierarchical Bayesian models to constrain the underlying planet composition distribution from a sample of noisy mass-radius measurements. This approach represents a promising avenue toward a quantitative measurement of the amount of physical scatter in small planet compositions, the identification of planet sub-populations that may be tied to distinct formation pathways, and empirical constraints on the dominant compositional trends in the planet sample. Both the transit and radial velocity techniques are subject to selection effects, and approaches to mitigate the resulting biases will be addressed. In addition to distilling composition-distribution insights from the current sample of Kepler planets with RV masses, this framework may be used to optimize the target selection for future transiting planet RV follow-up surveys.

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Harinantenaina, Liva, und Yoshinori Asakawa. „Malagasy Liverworts, Source of New and Biologically Active Compounds“. Natural Product Communications 2, Nr. 6 (Juni 2007): 1934578X0700200. http://dx.doi.org/10.1177/1934578x0700200616.

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The phytochemical investigation of eight Jungermaniales liverwort species: Bazzania decrescens, B. madagassa (Lepidoziaceae), Plagiochila barteri, P. terebrans (Plagiochilaceae), Isotachis aubertii (Isotachidaceae), Mastigophora diclados (Lepicoleaceae), Radula appressa (Radulaceae), and Thysananthus spathulistipus (Lejeuneaceae), collected from Madagascar, has been carried out to afford new and structurally interesting terpenoids and aromatic compounds. The biological activities of the isolated secondary metabolites were determined and the herbertene-type sesquiterpenoids were shown to have antibacterial activity. A new ent-clerodane diterpene from Thysananthus spathulistipus and bis-bibenzyls-type aromatic compounds exhibited strong inhibition of NO production in RAW 264.7 cells, while marchantin C produced moderate α-glucosidase inhibition. The chemosystematics of the studied species are discussed.

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Santos, Thauany Torres, Iago Vilar Lira, Rosilda Maria Batista, Samilla da Silva Andrade, Thais Margarida Silva Santos, Daniele de Oliveira Cabral Pessoa, Maria Eduarda de Lira Andrade und Tarcio Correia Campos. „Potencial farmacológico observado em canabinoide presente em plantas do gênero radula“. Brazilian Journal of Health Review 2, Nr. 6 (2019): 5785–88. http://dx.doi.org/10.34119/bjhrv2n6-072.

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OLIVEIRA-DA-SILVA, FUVIO RUBENS, S. ROBBERT GRADSTEIN und ANNA LUIZA ILKIU-BORGES. „A new species and a new variety of Radula Dumort. (Radulaceae, Marchantiophyta) from Brazil“. Phytotaxa 454, Nr. 1 (27.07.2020): 24–30. http://dx.doi.org/10.11646/phytotaxa.454.1.2.

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In the course of a taxonomic study of Radula in Brazil, a new species from Bahia and a new variety of R. fendleri from Rio de Janeiro were detected. The new species is characterized by plants irregularly pinnate, leaves oblong-ovate with entire to sinuate margins, cell walls with small trigones at leaf base and midleaf, increasing in size toward the leaf margins, and lobules distant to subimbricate with a rounded base, covering 2/3 to fully overlapping the stem. The new variety differs from the type variety by plants paroicous, leaf cells with trigones small or lacking, and absence of caducous leaves. A full description and illustration of the new taxa as well as comments on morphology, taxonomy, and distribution are provided.

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Blunt, Sarah, Adolfo Carvalho, Trevor J. David, Charles Beichman, Jon K. Zink, Eric Gaidos, Aida Behmard et al. „Overfitting Affects the Reliability of Radial Velocity Mass Estimates of the V1298 Tau Planets“. Astronomical Journal 166, Nr. 2 (14.07.2023): 62. http://dx.doi.org/10.3847/1538-3881/acde78.

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Abstract Mass, radius, and age measurements of young (≲100 Myr) planets have the power to shape our understanding of planet formation. However, young stars tend to be extremely variable in both photometry and radial velocity (RV) measurements, which makes constraining these properties challenging. The V1298 Tau system of four ∼0.5 R J planets transiting a pre-main-sequence star presents an important, if stress-inducing, opportunity to observe and measure directly the properties of infant planets. Suárez Mascareño et al. published radial-velocity-derived masses for two of the V1298 Tau planets using a state-of-the-art Gaussian process regression framework. The planetary densities computed from these masses were surprisingly high, implying extremely rapid contraction after formation in tension with most existing planet-formation theories. In an effort to constrain further the masses of the V1298 Tau planets, we obtained 36 RVs using Keck/HIRES, and analyzed them in concert with published RVs and photometry. Through performing a suite of cross-validation tests, we found evidence that the preferred model of Suárez Mascareño et al. suffers from overfitting, defined as the inability to predict unseen data, rendering the masses unreliable. We detail several potential causes of this overfitting, many of which may be important for other RV analyses of other active stars, and recommend that additional time and resources be allocated to understanding and mitigating activity in active young stars such as V1298 Tau.

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Jones, Hugh R. A., John Barnes, Mikko Tuomi, James S. Jenkins und Guillem Anglada-Escude. „Radial velocity studies of cool stars“. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, Nr. 2014 (28.04.2014): 20130088. http://dx.doi.org/10.1098/rsta.2013.0088.

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Our current view of exoplanets is one derived primarily from solar-like stars with a strong focus on understanding our Solar System. Our knowledge about the properties of exoplanets around the dominant stellar population by number, the so-called low-mass stars or M dwarfs, is much more cursory. Based on radial velocity discoveries, we find that the semi-major axis distribution of M dwarf planets appears to be broadly similar to those around more massive stars and thus formation and migration processes might be similar to heavier stars. However, we find that the mass of M dwarf planets is relatively much lower than the expected mass dependency based on stellar mass and thus infer that planet formation efficiency around low-mass stars is relatively impaired. We consider techniques to overcome the practical issue of obtaining good quality radial velocity data for M dwarfs despite their faintness and sustained activity and emphasize (i) the wavelength sensitivity of radial velocity signals, (ii) the combination of radial velocity data from different experiments for robust detection of small amplitude signals, and (iii) the selection of targets and radial velocity interpretation of late-type M dwarfs should consider H α behaviour.

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Ludwiczuk, Agnieszka, Fumihiro Nagashima, Rob S. Gradstein und Yoshinori Asakawa. „Volatile Components from Selected Mexican, Ecuadorian, Greek, German and Japanese Liverworts“. Natural Product Communications 3, Nr. 2 (Februar 2008): 1934578X0800300. http://dx.doi.org/10.1177/1934578x0800300205.

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Twenty-one liverworts from Mexico, Ecuador, Greece, Germany and Japan were extracted with diethyl ether and the crude extracts analyzed by TLC and GC/MS. Several volatile sesqui- and diterpenoids, and also bibenzyls were identified. Many of these compounds are important chemical markers of liverworts genus or family. Sacculatane-type diterpene dialdehydes occur in the Pelliaceae family, while bibenzyls, especially with a prenyl group are characteristic of the Japanese Radula perrottetii. Eudesman-type sesquiterpene lactones and pinguisane-type sesquiterpenoids are significant markers of Frullania tamarisci and Trocholejeunea sandvicensis, respectively. The Greek Fossombronia angulosa contained exactly the same compounds previously found in brown algae. Such chemical similarity suggests that some families of liverworts and algae may have an evolutionary relationship.

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Zurlo, A., D. Mesa, S. Desidera, S. Messina, R. Gratton, C. Moutou, J.-L. Beuzit et al. „Imaging radial velocity planets with SPHERE“. Monthly Notices of the Royal Astronomical Society 480, Nr. 1 (07.07.2018): 35–48. http://dx.doi.org/10.1093/mnras/sty1809.

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Standing, Matthew R., Amaury H. M. J. Triaud, João P. Faria, David V. Martin, Isabelle Boisse, Alexandre C. M. Correia, Magali Deleuil et al. „BEBOP II: sensitivity to sub-Saturn circumbinary planets using radial-velocities“. Monthly Notices of the Royal Astronomical Society 511, Nr. 3 (25.01.2022): 3571–83. http://dx.doi.org/10.1093/mnras/stac113.

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ABSTRACT BEBOP is a radial-velocity survey that monitors a sample of single-lined eclipsing binaries, in search of circumbinary planets by using high-resolution spectrographs. Here, we describe and test the methods we use to identify planetary signals within the BEBOP data and establish how we quantify our sensitivity to circumbinary planets by producing detection limits. This process is made easier and more robust by using a diffusive nested sampler. In the process of testing our methods, we notice that contrary to popular wisdom, assuming circular orbits in calculating detection limits for a radial-velocity survey provides overoptimistic detection limits by up to $40{{\ \rm per\ cent}}$ in semi-amplitude with implications for all radial-velocity surveys. We perform example analyses using three BEBOP targets from our Southern HARPS survey. We demonstrate for the first time a repeated ability to reach a residual root mean squared scatter of $3\, \rm m\, s^{-1}$ (after removing the binary signal), and find that we are sensitive to circumbinary planets with masses down to that of Neptune and Saturn, for orbital periods up to $1000\, \rm d$.

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Korhonen, Heidi, Jan Marie Andersen und Silva Järvinen. „Starspot-Induced Radial Velocity Jitter During a Stellar Cycle“. Proceedings of the International Astronomical Union 8, S293 (August 2012): 382–84. http://dx.doi.org/10.1017/s1743921313013203.

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AbstractLate-type stars exhibit cool regions on their surface, the stellar equivalent of sunspots. These dark starspots can also mimic the radial velocity variations caused by orbiting planets, making it at times difficult to distinguish between planets and activity signatures. The amount of spots on the Sun and other cool stars changes cyclically during an activity cycle, which has length varying from about a year to longer than the solar 11 years. In this work we investigate the influence of varying amount of starspots on the sparsely sampled radial velocity observations - which are the norm in the radial velocity studies searching for exoplanets on wide orbits. We study two simulated cases: one with a random spot configuration, and one where the spot occurrence is concentrated. In addition we use Doppler images of young solar analogue V889 Her as a high activity case.

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