19 research outputs found
ExoClock Project: An open platform for monitoring the ephemerides of Ariel targets with contributions from the public
The Ariel mission will observe spectroscopically around 1000 exoplanets to further characterise their atmospheres. For the mission to be as efficient as possible, a good knowledge of the planets' ephemerides is needed before its launch in 2028. While ephemerides for some planets are being refined on a per-case basis, an organised effort to collectively verify or update them when necessary does not exist. In this study, we introduce the ExoClock project, an open, integrated and interactive platform with the purpose of producing a confirmed list of ephemerides for the planets that will be observed by Ariel. The project has been developed in a manner to make the best use of all available resources: observations reported in the literature, observations from space instruments and, mainly, observations from ground-based telescopes, including both professional and amateur observatories. To facilitate inexperienced observers and at the same time achieve homogeneity in the results, we created data collection and validation protocols, educational material and easy to use interfaces, open to everyone. ExoClock was launched in September 2019 and now counts over 140 participants from more than 15 countries around the world. In this release, we report the results of observations obtained until the 15h of April 2020 for 119 Ariel candidate targets. In total, 632 observations were used to either verify or update the ephemerides of 83 planets. Additionally, we developed the Exoplanet Characterisation Catalogue (ECC), a catalogue built in a consistent way to assist the ephemeris refinement process. So far, the collaborative open framework of the ExoClock project has proven to be highly efficient in coordinating scientific efforts involving diverse audiences. Therefore, we believe that it is a paradigm that can be applied in the future for other research purposes, too
Evaluating model outputs using integrated global speleothem records of climate change since the last glacial
Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercomparison Project Phase 6, so it is timely to evaluate different approaches to using the speleothem data for data–model comparisons. Here, we illustrate this using 456 globally distributed speleothem δ18O records from an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled atmospheric circulation model. We show that the SISAL records reproduce the first-order spatial patterns of isotopic variability in the modern day, strongly supporting the application of this dataset for evaluating model-derived isotope variability into the past. However, the discontinuous nature of many speleothem records complicates the process of procuring large numbers of records if data–model comparisons are made using the traditional approach of comparing anomalies between a control period and a given palaeoclimate experiment. To circumvent this issue, we illustrate techniques through which the absolute isotope values during any time period could be used for model evaluation. Specifically, we show that speleothem isotope records allow an assessment of a model's ability to simulate spatial isotopic trends. Our analyses provide a protocol for using speleothem isotope data for model evaluation, including screening the observations to take into account the impact of speleothem mineralogy on δ18O values, the optimum period for the modern observational baseline and the selection of an appropriate time window for creating means of the isotope data for palaeo-time-slices
PARASITISM OF FRUIT FLIES (TEPHRITIDAE) IN FIELD, AFTER THE RELEASES OF Diachasmimorpha longicaudata (ASHMEAD) (HYMENOPTERA: BRACONIDAE) IN RIO GRANDE DO SUL
Holocene Cyclic Records of Ice-Rafted Debris and Sea Ice Variations on the East Greenland and Northwest Iceland Margins
The dynamics of the Greenland Ice Sheet and drift of sea ice from the Arctic Ocean reaching Denmark Strait are poorly constrained. We present data on the provenance of Fe oxide detrital grains from two cores in the Denmark Strait area and compare the Fe grain source data with other environmental proxies in order to document the variations and potential periodicities in ice-rafted debris delivery during the Holocene. Based on their Fe grain geochemistry, the sediments can be traced to East Greenland sources and to more distal sites around the Arctic Basin. On the Holocene time scales of the two cores, sea ice biomarker (IP25) data, and quartz weight percent reveal positive associations with T°C and inverse associations with biogenic carbonate wt%. Trends in the data were obtained from Singular Spectrum Analysis (SSA), and residuals were tested for cyclicity. Trends on the environmental proxies explained between 15 and 90% of the variance. At both sites the primary Fe grain sources were from Greenland, but significant contributions were also noted from Banks Island and Svalbard. There is a prominent cyclicity of 800 yrs as well as other less prominent cycles for both Greenland and arctic sources. The Fe grain sources from Greenland and the circum-Arctic Ocean are in synchronization, suggesting that the forcings for these cycles are regional and not local ice sheet instabilities
Record of lonchaeids (Diptera: Lonchaeidae) in municipalities of Alagoas State, Brazil.
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Record of lonchaeids (Diptera: Lonchaeidae) in municipalities of Alagoas State, Brazil.
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Previous issue date: 2019-01-17bitstream/item/191271/1/ART18115.pd
Last glacial and Holocene stable isotope record of fossil dripwater from subtropical Brazil based on analysis of fluid inclusions in stalagmites
The stable isotope composition of fossil dripwater preserved in stalagmites fluid inclusions is a promising tool to reconstruct paleopluviosity in the tropics and subtropics. Here we present δD and δ18O records of fossil dripwater from two stalagmites collected in Botuverá Cave (subtropical Brazil), covering the last glacial period and the Holocene. The observed millennial-scale variability of fossil dripwater δD and δ18O values is of the order of 10 to 20‰ and 1 to 3.5‰ (V-SMOW), respectively. Fluid inclusion δD and δ18O values are higher than the weighted mean δD and δ18O values of modern precipitation, suggesting a possible intensification of extratropical cold surges during both the last glacial period and the Early Holocene, followed by a progressive Late Holocene transition towards modern pluviosity conditions. Fluid inclusions δ18O values vary in parallel with stalagmite δ18O values during the Holocene but not during the last glacial period. This suggests that the δ18O value of precipitation may not be the only dominant factor controlling the δ18O values of the analyzed stalagmites. Isotope disequilibrium effects arising from Prior Calcite Precipitation (PCP) possibly affected stalagmites δ18O values to a greater extent than previously considered, though this effect does not bias non-quantitative paleopluviosity reconstructions based on stalagmite δ18O values. Isotope-based paleotemperature calculated for the Late Holocene matches modern cave temperature (19 °C) within ± 2.4 °C. This encourages further application of isotope analyses of fluid inclusion for climatic reconstructions
Provenance and sedimentary environments of the Proterozoic S\ue3o Roque Group, SE-Brazil: Contributions from petrography, geochemistry and Sm-Nd isotopic systematics of metasedimentary rocks
The Proterozoic metasedimentary sequences exposed in the S\ue3o Roque Domain (Apia\ued Terrane, Ribeira Belt, southeast Brazil) consist of metasandstones and meta-felspathic wackes with some volcanic layers of within-plate geochemical signature (Boturuna Formation), a passive margin turbidite sequence of metawackes and metamudstones (Piragibu Formation), and volcano-sedimentary sequences with MORB-like basalts (Serra do Itaberaba Group; Pirapora do Bom Jesus Formation). A combination of zircon provenance studies in metasandstones, whole-rock geochemistry and Sm-Nd isotopic systematics in metamudstones was used to understand the provenance and tectonic significance of these sequences, and their implications to the evolution of the Precambrian crust in the region.Whole-rock geochemistry of metamudstones, dominantly from the Piragibu Formation, points to largely granitic sources (as indicated for instance by LREE-rich moderately fractionated REE patterns and subtle negative Eu anomalies) with some mafic contribution (responding for higher contents of Fe2O3, MgO, V, and Cr) and were subject to moderate weathering (CIA - 51 to 85). Sm-Nd isotope data show three main peaks of Nd TDM ages at ca. 1.9, 2.1 and 2.4 Ga; the younger ages define an upper limit for the deposition of the unit, and reflect greater contributions from sources younger than the >2.1 Ga basement.The coincident age peaks of Nd TDM and U-Pb detrital zircons at 2.1-2.2 Ga and 2.4-2.5 Ga, combined with the possible presence of a small amount of zircons derived from mafic (gabbroid) sources with the same ages, as indicated by a parallel LA-ICPMS U-Pb dating study in metapsammites, are suggestive that these were major periods of crustal growth in the sources involving not only crust recycling but also some juvenile addition.A derivation from similar older Proterozoic sources deposited in a passive margin basin is consistent with the main sedimentary sequences in the S\ue3o Roque Domain being broadly coeval and in part laterally continuous. The coincident age, Sm-Nd isotope signature and geographic proximity make the exposures of basement orthogneisses in the Apia\ued Terrane candidates for source material to the S\ue3o Roque Domain. Additional sources with younger Nd TDM could be juvenile 2.2 Ga basement from the southern portion of the S\ue3o Francisco Craton and its marginal belts (e.g., Mineiro Belt and Juiz de Fora Complex)
Infestación natural de Lonchaeidae (Diptera) en variedades de melocotón
Se estudió la ocurrencia de Lonchaeidae en variedades de melocotón, conducidos sobre los patrones ‘Okinawa’ y Umê: Tropical, Ouromel 3, Jóia 4, Régis, Talismã, Aurora 2, Aurora 1, Dourado 2 y Doçura 2. Se colectaron muestras de 30 frutos por planta en el Banco de Germoplasma en Presidente Prudente, Brasil. Se obtuvieron 633 especímenes de Lonchaeidae; 394 de ellos en frutos de variedades sobre ‘Okinawa’ y 239 sobre Umê. Se capturaron especies como Neosilba zadolicha, N. inesperata, N. pendula, N. certa y Neosilba spp. (hembras). N. zadolicha y N. inesperata, se observaron en 77,78% de las muestras de las variedades sobre ‘Okinawa’. Sobre el patrón Umê la mayor incidencia fue de N. zadolicha , N. inesperata y N. pendula (55,6%, 33,3% y 33,3% respectivamente). Las variedades Ouromel 3, Talismã, Doçura 2 y Aurora 2 presentaron mayores infestaciones por Lonchaeidae. N. certa tuvo una menor incidencia y sólo se observó en la variedad Doçura 2 sobre ‘Okinawa’. Plantas con mayor número de frutos presentaron mayor incidencia de moscas por fruto; sin embargo, no hubo correlación entre peso del fruto y número de moscas. No se observó diferencia para peso del fruto y número de moscas por fruto entre los dos patrones, ‘Okinawa’ y Umê. Melocotones crecidos en los patrones ‘Okinawa’ y Umê en Presidente Prudente están infestados por especies de Lonchaeidae que presentan preferencia independientemente del peso de los frutos. El aporte de este trabajo al conocimiento de la comunidad de especies de Lonchaeidae ofrece una base para su control.The occurrence of Lonchaeidae was studied in peach fruit varieties on the rootstocks 'Okinawa' and Ume: Tropical, Ouromel 3, Joia 4, Regis, Talisma, Aurora 2, Aurora 1, Dourado 2 and Docura 2. Samples of 30 fruits were collected from each available plant in the Germplasm Bank located in Presidente Prudente, Brazil. A total of 633 specimens of Lonchaeidae were obtained with 394 from fruit varieties on 'Okinawa' and 239 on Ume. Captured species included Neosilba zadolicha, N. inesperata, N. pendula, N. cella, and Neosilba spp. (females). N. zadolicha and N. inesperata were observed in 77.78% of samples from the varieties on 'Okinawa'. on the lime rootstock, the greatest incidence was of N. zadolicha, N. inesperata and N. penduda (55.6%, 33.3% and 33.3%). The varieties Ouromel 3, Talisma, Docura 2 and Aurora 2 had the highest infestation rates by Lonchaeidae. N. certa had the lowest incidence and was only observed in the variety Docura 2 on 'Okinawa'. Plants with more fruits showed a higher incidence of flies per fruit. Nevertheless, there was no significant correlation between fruit weight and fly number. No significant difference was observed in fruit weight and number of flies per fruit between the two rootstocks, 'Okinawa' and lime. Peaches grown on 'Okinawa' and Ume rootstocks in the city of Presidente Prudente, are infested by Lonchaeidae species that present a preference for the different varieties, independent of fruit weight. This is a contribution to an understanding of the community of Lonchaeidae species, which provides a basis for their control