Abstract
Constraining planet formation based on the atmospheric composition of exoplanets is a fundamental goal of the exoplanet community. Existing studies commonly try to constrain atmospheric ...abundances, or to analyze what abundance patterns a given description of planet formation predicts. However, there is also a pressing need to develop methodologies that investigate how to transform atmospheric compositions into planetary formation inferences. In this study we summarize the complexities and uncertainties of state-of-the-art planet formation models and how they influence planetary atmospheric compositions. We introduce a methodology that explores the effect of different formation model assumptions when interpreting atmospheric compositions. We apply this framework to the directly imaged planet HR 8799e. Based on its atmospheric composition, this planet may have migrated significantly during its formation. We show that including the chemical evolution of the protoplanetary disk leads to a reduced need for migration. Moreover, we find that pebble accretion can reproduce the planet’s composition, but some of our tested setups lead to too low atmospheric metallicities, even when considering that evaporating pebbles may enrich the disk gas. We conclude that the definitive inversion from atmospheric abundances to planet formation for a given planet may be challenging, but a qualitative understanding of the effects of different formation models is possible, opening up pathways for new investigations.
There is ongoing debate as to the subduction direction of the Bangong–Nujiang Ocean during the Mesozoic (northward, southward or bidirectional subduction). Arc-related intermediate to felsic ...intrusions could mark the location of the subduction zone and, more importantly, elucidate the dominant geodynamic processes. We report whole rock geochemical and zircon U–Pb and Hf isotopic data for granitoids from the west central Lhasa subterrane (E80° to E86°). All rocks show metaluminous to peraluminous, calc-alkaline signatures, with strong depletion of Nb, Ta and Ti, enrichment of large ion lithophile elements (e.g., Cs, Rb, K), a negative correlation between SiO2 and P2O5, and a positive correlation between Rb and Th. All these features are indicative of I-type arc magmatism. New zircon U–Pb results, together with data from the literature, indicate continuous magmatism from the Late Jurassic to the Early Cretaceous (160 to 130Ma). Zircon U–Pb ages for samples from the northern part of the west central Lhasa subterrane (E80° to E82°30′) yielded formation ages of 165 to 150Ma, whereas ages of 142 to 130Ma were obtained on samples from the south. This suggests flat or low-angle subduction of the Bangong–Nujiang Ocean, consistent with a slight southward decrease in zircon εHf(t) values for Late Jurassic rocks. Considering the crustal shortening, the distance from the Bangong–Nujiang suture zone, and a typical subduction zone melting depth of ~100km, the subduction angle was less than 14° for Late Jurassic magmatism in the central Lhasa interior, consistent with flat or low-angle subduction. Compared with Late Jurassic rocks (main εHf(t) values of −16 to −7), Early Cretaceous rocks (145 to 130Ma) show markedly higher εHf(t) values (mainly −8 to 0), possibly indicating slab roll-back, likely caused by slab foundering or break-off. Combined with previously published works on arc magmatism in the central Lhasa and west part of the southern Qiangtang subterranes, our results support the bidirectional subduction of the Bangong–Nujiang Ocean along the Bangong–Nujiang Suture Zone, and indicates flat or low-angle southward subduction (165 to 145Ma) followed by slab roll-back (145 to 130Ma).
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•All the granitoids sampled from the west central Lhasa subterrane are arc magmatism.•These rocks show continuous zircon U–Pb ages from 160 to 130Ma.•Our results support the bidirectional subduction of the Bangong–Nujiang Ocean.•Flat or low-angle subduction followed by slab roll-back likely developed.
This bold challenge to conventional notions about medieval music disputes the assumption of pure literacy and replaces it with a more complex picture of a world in which literacy and orality ...interacted. Asking such fundamental questions as how singers managed to memorize such an enormous amount of music and how music composed in the mind rather than in writing affected musical style, Anna Maria Busse Berger explores the impact of the art of memory on the composition and transmission of medieval music. Her fresh, innovative study shows that although writing allowed composers to work out pieces in the mind, it did not make memorization redundant but allowed for new ways to commit material to memory. Since some of the polyphonic music from the twelfth century and later was written down, scholars have long assumed that it was all composed and transmitted in written form. Our understanding of medieval music has been profoundly shaped by German philologists from the beginning of the last century who approached medieval music as if it were no different from music of the nineteenth century. But Medieval Music and the Art of Memory deftly demonstrates that the fact that a piece was written down does not necessarily mean that it was conceived and transmitted in writing. Busse Berger's new model, one that emphasizes the interplay of literate and oral composition and transmission, deepens and enriches current understandings of medieval music and opens the field for fresh interpretations.
Commercially important edible nut seeds were analyzed for chemical composition and moisture sorption. Moisture (1.47−9.51%), protein (7.50−21.56%), lipid (42.88−66.71%), ash (1.16−3.28%), total ...soluble sugars (0.55−3.96%), tannins (0.01−0.88%), and phytate (0.15−0.35%) contents varied considerably. Regardless of the seed type, lipids were mainly composed of mono- and polyunsaturated fatty acids (>75% of the total lipids). Fatty acid composition analysis indicated that oleic acid (C18:1) was the main constituent of monounsaturated lipids in all seed samples. With the exception of macadamia, linoleic acid (C18:2) was the major polyunsaturated fatty acid. In the case of walnuts, in addition to linoleic acid (59.79%) linolenic acid (C18:3) also significantly contributed toward the total polyunsaturated lipids. Amino acid composition analyses indicated lysine (Brazil nut, cashew nut, hazelnut, pine nut, and walnut), sulfur amino acids methionine and cysteine (almond), tryptophan (macadamia, pecan), and threonine (peanut) to be the first limiting amino acid as compared to human (2−5 year old) amino acid requirements. The amino acid composition of the seeds was characterized by the dominance of hydrophobic (range = 37.16−44.54%) and acidic (27.95−33.17%) amino acids followed by basic (16.16−21.17%) and hydrophilic (8.48−11.74%) amino acids. Trypsin inhibitory activity, hemagglutinating activity, and proteolytic activity were not detected in the nut seed samples analyzed. Sorption isotherms (A w range = 0.08−0.97) indicated a narrow range for monolayer water content (11−29 mg/g of dry matter). No visible mold growth was evident on any of the samples stored at A w < 0.53 and 25 °C for 6 months. Keywords: Tree nuts; chemical composition; protein; lipids; fatty acids; phytates; tannins; amino acids; storage; sorption isotherm
Crude glycerol is the primary byproduct of the biodiesel industry. Producing docosahexaenoic acid (DHA, 22:6 n-3) through fermentation of the alga Schizochytrium limacinum on crude glycerol provides ...a unique opportunity to utilize a large quantity of this byproduct. The objective of this work is to investigate the effects of impurities contained in the crude glycerol on DHA production and algal biomass composition. Crude glycerol streams were obtained from different biodiesel refineries. All of the glycerol samples contained methanol, soaps, and various elements including calcium, phosphorus, potassium, silicon, sodium, and zinc. Both methanol and soap were found to negatively influence algal DHA production; these two impurities can be removed from culture medium by evaporation through autoclaving (for methanol) and by precipitation through pH adjustment (for soap). The glycerol-derived algal biomass contained 45−50% lipid, 14−20% protein, and 25% carbohydrate, with 8−13% ash content. Palmitic acid (C16:0) and DHA were the two major fatty acids in the algal lipid. The algal biomass was rich in lysine and cysteine, relative to many common feedstuffs. Elemental analysis by inductively coupled plasma showed that boron, calcium, copper, iron, magnesium, phosphorus, potassium, silicon, sodium, and sulfur were present in the biomass, whereas no heavy metals (such as mercury) were detected in the algal biomass. Overall, the results show that crude glycerol was a suitable carbon source for algal fermentation. The crude glycerol-derived algal biomass had a high level of DHA and a nutritional profile similar to that of commercial algal biomass, suggesting a great potential for using crude glycerol-derived algae in omega-3-fortified food or feed.
For a multi-resource service request task (MRSRTask) in manufacturing grid (MGrid) system, in addition to the search for all qualified resource services according to each subtask, the system selects ...one candidate resource service for each subtask. Then the system generates a new composite resource service (CRS) and selects the optimal resource service composite path from all possible paths to execute the task with the given multi-objective (e.g., time minimization, cost minimization and reliability maximization) and multi-constraints. The above problem is defined as multi-objective MGrid resource service composition and optimal-selection (MO-MRSCOS) problem. The formulation is presented for an MO-MRSCOS problem. The correlations among resource services are taken into account during MGrid resource service composition, and a QoS description mode supporting resource service correlation is presented. The basic resource service composite modes (RSCM) for CRS are described, and the principles for translating a complicated RSCM into a simple sequence RSCM are presented for simplifying the resolving process and complexity of MO-MRSCOS problem. A new method based on the principles of particle swarm optimization (PSO), is proposed for solving MO-MRSCOS problem. Unlike previous works: (a) the proposed PSO algorithms combine the non-dominated sorting technique to achieve the selection of global best position and private best position; (b) the parameters of particle updating formulation in PSO are dynamical generated in order to make a compromise between the global exploration and local exploitation abilities of PSO; (c)
permutation-based and
objective-based population trimming operators are applied in PSO to maintain diversity of solutions in population. The experimental results and performance comparison show that the proposed method is both effective and efficient.
Geochemical and geochronologic data are presented for meta-mafic to meta-felsic rocks along the Paleo-Tethys Suture in the Binalood Mountains east of Neyshabur, NE Iran. The rocks have a late ...Cambrian age (U–Pb zircon, ~ 490 Ma) and were metamorphosed in the Early Jurassic (
40
Ar/
39
Ar amphibole and plagioclase, 199–192 Ma). The rocks of this suite are alkaline and sub-alkaline (tholeiitic). The alkaline rocks are enriched in light relative to heavy rare earth elements, and do not show depletion of high-field strength elements on primitive mantle-normalized multi-element diagrams; they are similar to ocean island basalts (OIB). The tholeiitic rocks are depleted in Nb and Ta and have higher MgO and lower TiO
2
than the alkaline rocks. Both types have similar, high and variable
87
Sr/
86
Sr
(i)
isotopic compositions of 0.7044 to 0.7082 and
143
Nd/
144
Nd
(i)
values of 0.5118 to 0.5122. The alkaline rocks are lower-degree partial melts than the tholeiitic rocks and were generated at greater depths; they likely originated from a garnet pyroxenite-rich source. The spatial, temporal, and geochemical relationships of early Paleozoic meta-mafic to felsic rocks along the Paleo-Tethys Suture (e.g., Shahrud, Jajarm, Binalood, Torbat-e-Jam) substantiate the role of a mantle plume in continental breakup along the northern margin of Gondwana and a late Cambrian-Ordovician onset of rifting that resulted in the opening of the Paleo-Tethys Ocean. The Early Jurassic metamorphism post-dates its closure.
Graphical abstract
Earth's continental crust is dominantly made of buoyant, felsic igneous material (granitoids), that was ultimately extracted from the mantle as a result of Earth's differentiation. Since felsic melts ...are not in chemical equilibrium with the mantle, they can originate either from melting of older crustal lithologies, or from differentiation of a primitive mantle melt; only the latter case will contribute to crustal growth. To understand the mechanisms of continental crust growth and differentiation through time, it is therefore necessary to unravel the respective contribution of these two different mechanisms in the genesis of granitoid suites. In modern Earth, granitoids are chiefly generated in convergent plate boundaries (subduction and collision). This paper examines the granitic suites in a late-collision environment, the Variscan French Massif Central (FMC), and compares them with the suites found in an oceanic arc. We therefore describe, and compare, two end-members sites of granite generation.
In the FMC, several main types of granites are described. Muscovite and Cordierite bearing Peraluminous Granites (resp. MPG and CPG) contain large amounts of inherited zircons, and their chemistry demonstrates that their sources were older crustal material (resp. metasediments and metaigneous). On the other hand, Potassic Calc-alkaline Granites (KCG), associated to potassic diorites (vaugnerites) do not contain inherited zircons, and ultimately derive from the vaugnerites. The vaugnerites in turn form by partial melting of a mantle contaminated by the regional crust. Therefore, although they are isotopically similar to the crust, the KCG are net contributors to crustal growth. Thus we conclude that although late-orogenic settings are dominated by crustal melting and recycling, they may be sites of net crustal growth, even though this is not visible from isotopes only. In contrast, arc granitoids are purely or almost purely mantle derived. However, the preservation potential of arcs is much smaller than the preservation of late-orogenic domains, such that at the scale of a whole orogenic belt, late-orogenic magmatism is probably as important as arc magmatism.
Finally, we speculate that the situation may have been similar in the Archaean, or even more skewed towards late-orogenic sites (or similar environments, dominated by melting of an altered mafic protocrust), owing to the hotter mantle and less stable subductions during that period.
•We describe the different granite types in a late collision environment, the Variscan French Massif Central (FMC).•Most granitoids are crustal melts Some granites are mantle-derived, but have isotopic properties controlled by small amounts of crustal recycling to the mantle.•Late-collision sites are significant for crustal growth; although less efficient than subductions, they are better preserved.•Sites similar to late collision may be a realistic alternative to supra-subduction arcs for Archaean crustal growth.
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