scholarly journals Delivery of carbon, nitrogen, and sulfur to the silicate Earth by a giant impact

2019 ◽  
Vol 5 (1) ◽  
pp. eaau3669 ◽  
Author(s):  
Damanveer S. Grewal ◽  
Rajdeep Dasgupta ◽  
Chenguang Sun ◽  
Kyusei Tsuno ◽  
Gelu Costin
Keyword(s):  
Building Blocks ◽  
Major And Trace Elements ◽  
Isotopic Signatures ◽  
Left Behind ◽  
Inverse Monte Carlo ◽  
Planetary Embryo ◽  
Enstatite Chondrite ◽  
Magma Oceans ◽  
The Impact ◽  
Late Veneer

Earth’s status as the only life-sustaining planet is a result of the timing and delivery mechanism of carbon (C), nitrogen (N), sulfur (S), and hydrogen (H). On the basis of their isotopic signatures, terrestrial volatiles are thought to have derived from carbonaceous chondrites, while the isotopic compositions of nonvolatile major and trace elements suggest that enstatite chondrite–like materials are the primary building blocks of Earth. However, the C/N ratio of the bulk silicate Earth (BSE) is superchondritic, which rules out volatile delivery by a chondritic late veneer. In addition, if delivered during the main phase of Earth’s accretion, then, owing to the greater siderophile (metal loving) nature of C relative to N, core formation should have left behind a subchondritic C/N ratio in the BSE. Here, we present high pressure-temperature experiments to constrain the fate of mixed C-N-S volatiles during core-mantle segregation in the planetary embryo magma oceans and show that C becomes much less siderophile in N-bearing and S-rich alloys, while the siderophile character of N remains largely unaffected in the presence of S. Using the new data and inverse Monte Carlo simulations, we show that the impact of a Mars-sized planet, having minimal contributions from carbonaceous chondrite-like material and coinciding with the Moon-forming event, can be the source of major volatiles in the BSE.

Mechanically-Tunable Quantum Interference in Ferrocene-Based Single-Molecule Junctions

2020 ◽  
Author(s):  
María Camarasa-Gómez ◽  
Daniel Hernangómez-Pérez ◽  
Michael S. Inkpen ◽  
Giacomo Lovat ◽  
E-Dean Fung ◽  
...  
Keyword(s):  
Single Molecule ◽  
Quantum Interference ◽  
Degrees Of Freedom ◽  
Building Blocks ◽  
Ferrocene Derivative ◽  
Single Molecule Junctions ◽  
Molecule Junction ◽  
Single Molecule Junction ◽  
The Impact ◽  
D Orbitals

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted<br>some interest as functional elements of molecular-scale devices. Here we investigate the impact of<br>the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction<br>conductance. Measurements indicate that the conductance of the ferrocene derivative, which is<br>suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated<br>by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.<br>

Model Pembelajaran Teams Games Tournaments (TGT) untuk Meningkatkan Hasil Belajar Siswa

2019 ◽  
Vol 3 (2) ◽  
pp. 110
Author(s):  
Suwarno Suwarno
Keyword(s):  
Social Capital ◽  
Academic Success ◽  
Service Learning ◽  
Learning Outcomes ◽  
School Effectiveness ◽  
Social Trust ◽  
Building Blocks ◽  
Learning Model ◽  
Committee Report ◽  
The Impact

<p><strong>A</strong><strong>bstract</strong><strong>. </strong>This study aims to determine the effectiveness of the Teams Games Tournament (TGT) learning model to improve student learning outcomes. This research is important because the lecture learning model makes learning meaningless so it impacts on low learning outcomes. This research uses quasi experiment using control class and experimental class. Respondents in this study were students of class X SMK 8 Semarang Academic Year 2017/2018. Sample selection using random sampling, class X1 is <em>used</em> as a control class and X2 is an experimental class. The experimental class was given an intervention by learning Teams Games Tournaments (TGT), while the control class used lecture learning. The effectiveness of the model was measured by the student test analysis method. then analyzed by completeness test and average difference test. The findings of this study are the learning outcomes of experimental class students achieving better learning outcomes than classes using the lecture method.</p><p><strong><em>Keywords</em></strong><em>: Learning Model, Teams Games Tournaments (TGT)</em><em>. Students</em></p><p><strong><br /></strong></p><p><strong>Daftar Pustaka</strong></p><p align="center"> </p><p>Bofota, Y. B., &amp; Bofota, Y. B. (2017). <em>The impact of social capital on children educational outcomes : the case of Tanzania The impact of social capital on children educational outcomes : The case of Tanzania</em>.</p><p>Cahuc, P., Shleifer, A., &amp; Algan, Y. (2014). <em>Teaching Practices and Social Capital</em>. (6052).</p><p>Catts, R., &amp; Ozga, J. (2015). <em>What is Social Capital and how might it be used in Scotland ’ s Schools ?</em> (36).</p><p>Flint, N. (2017). <em>Full report Schools , communities and social capital : building blocks in the ’ Big Society ’ Contents</em>.</p><p>Goddard, R. D. (2016). <em>Relational Networks , Social Trust , and Norms : A Social Capital Perspective on Students ’ Chances of Academic Success</em>. <em>25</em>(1), 59–74.</p><p>Eddy Prasongko, 2017. Team Game Tournament. Bandung. Jawa Barat</p><p>Endang Poerwanti, dkk. 2008. <em>Asesmen Pembelajaran SD.</em> Jakarta: Direktorat Jendral Pendidikan Tinggi Departemen Pendidikan Nasional</p><p>Hargreaves, A. (2015). <em>School Social Capital and School Effectiveness</em>. <em>37</em>, 119–136.</p><p>Kurnia, Inggridwati. dkk. 2018. <em>Perkembangan belajar peserta didik</em><em>.</em> Jakarta: Direktorat Jendral Pendidikan Tinggi Departemen Pendidikan Nasional</p><p>Purwanto. M Ngalim. 2015. <em>Psikologi Pendidikan</em>. Bandung: PT Remaja Rosdakarya</p><p>Siddiq, M. Djauhar. 2018. <em>Pengembangan Bahan Pembelajaran SD</em>. Jakarta: Direktorat Jendral Pendidikan Tinggi Departemen Pendidikan Nasional.</p><p>Sugiyono, 2005. Metode Penelitian Kuantitatif, Kualitatif dan Rn D, Bandung Aftabeta</p><p>Lash, D., &amp; Belfiore, G. (2017). <em>5 Essentials in Building Social Capital Report 4 of the MyWays Student Success Series</em>. (October).</p><p>Mikiewicz, P., Jonasson, J. T., Gudmundsson, G., Blondal, K. S., &amp; Korczewska, D. M. (2011). <em>Comparative research between Poland and Iceland</em>.</p><p>Schlesselman, L., Borrego, M., Bloom, T. J., Mehta, B., Drobitch, R. K., &amp; Smith, T. (2015). An Assessment Of Service-Learning In 34 US Schools Of Pharmacy Follow Up On The 2001 Professional Affairs Committee Report. <em>American Journal of Pharmaceutical Education</em>, <em>79</em>(8). https://doi.org/10.5688/ajpe798116</p><p><em><br /></em></p>

Development of Strategies for Glycopeptide Synthesis: An Overview on the Glycosidic Linkage

2020 ◽  
Vol 24 (21) ◽  
pp. 2475-2497
Author(s):  
Andrea Verónica Rodríguez-Mayor ◽  
German Jesid Peralta-Camacho ◽  
Karen Johanna Cárdenas-Martínez ◽  
Javier Eduardo García-Castañeda
Keyword(s):  
Chemical Synthesis ◽  
Solid Phase ◽  
Building Blocks ◽  
Heterogeneous Environments ◽  
Phase Synthesis ◽  
Low Concentrations ◽  
Biological Sources ◽  
Synthetic Routes ◽  
The Impact ◽  
Potential Use

Glycoproteins and glycopeptides are an interesting focus of research, because of their potential use as therapeutic agents, since they are related to carbohydrate-carbohydrate, carbohydrate-protein, and carbohydrate-lipid interactions, which are commonly involved in biological processes. It has been established that natural glycoconjugates could be an important source of templates for the design and development of molecules with therapeutic applications. However, isolating large quantities of glycoconjugates from biological sources with the required purity is extremely complex, because these molecules are found in heterogeneous environments and in very low concentrations. As an alternative to solving this problem, the chemical synthesis of glycoconjugates has been developed. In this context, several methods for the synthesis of glycopeptides in solution and/or solid-phase have been reported. In most of these methods, glycosylated amino acid derivatives are used as building blocks for both solution and solid-phase synthesis. The synthetic viability of glycoconjugates is a critical parameter for allowing their use as drugs to mitigate the impact of microbial resistance and/or cancer. However, the chemical synthesis of glycoconjugates is a challenge, because these molecules possess multiple reaction sites and have a very specific stereochemistry. Therefore, it is necessary to design and implement synthetic routes, which may involve various protection schemes but can be stereoselective, environmentally friendly, and high-yielding. This review focuses on glycopeptide synthesis by recapitulating the progress made over the last 15 years.

scholarly journals Ontogenetic shift in the trophic role of the invasive killer shrimp Dikerogammarus villosus: a stable isotope study

2021 ◽  
Author(s):  
Francesco Mancini ◽  
Raffaele De Giorgi ◽  
Alessandro Ludovisi ◽  
Salvatrice Vizzini ◽  
Giorgio Mancinelli
Keyword(s):  
Dietary Habits ◽  
Trophic Position ◽  
Ecological Impact ◽  
Central Italy ◽  
Local Conditions ◽  
Dikerogammarus Villosus ◽  
Isotopic Signatures ◽  
Depth Analysis ◽  
Stable Isotope Study ◽  
The Impact

AbstractThe introduction of the amphipod Dikerogammarus villosus in European fresh waters is to date recognized as a threat to the integrity of invaded communities. Predation by D. villosus on native benthic invertebrates is assumed as the key determinant of its ecological impact, yet available information describe the species as a primary consumer as well as a carnivore depending on local conditions. Here, we assessed the trophic position (TP) of D. villosus in Lake Trasimeno, a recently invaded lentic system in central Italy, using the CN isotopic signatures of individuals captured in winter spanning two orders of magnitude in body size. TP estimations were compared with those characterizing the native amphipod Echinogammarus veneris and other representative invertebrate predators. On average, D. villosus showed a trophic position higher than E. veneris, and comparable with that of odonate nymphs. An in-depth analysis revealed that large-sized individuals had a trophic position of 3.07, higher than odonates and close to that of the hirudinean predator Erpobdella octoculata, while small-sized specimens had a trophic position of 2.57, similar to that of E. veneris (2.41). These findings indicate that size-related ontogenetic shifts in dietary habits may per se vary the nature of the interaction between Dikerogammarus villosus and native invertebrates from competition to predation. Information collated from published isotopic studies corroborated the generality of our results. We conclude that intra-specific trophic flexibility may potentially amplify and make more multifaceted the impact of the species on other invertebrate species in invaded food webs.

scholarly journals Progress and challenges of implantable neural interfaces based on nature-derived materials

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Eugenio Redolfi Riva ◽  
Silvestro Micera
Keyword(s):  
Interface Design ◽  
Specific Area ◽  
Building Blocks ◽  
Matrix Proteins ◽  
Neural Interface ◽  
Neural Interfaces ◽  
Biomedical Science ◽  
Chronic Inflammatory Response ◽  
The Impact

AbstractNeural interfaces are bioelectronic devices capable of stimulating a population of neurons or nerve fascicles and recording electrical signals in a specific area. Despite their success in restoring sensory-motor functions in people with disabilities, their long-term exploitation is still limited by poor biocompatibility, mechanical mismatch between the device and neural tissue and the risk of a chronic inflammatory response upon implantation.In this context, the use of nature-derived materials can help address these issues. Examples of these materials, such as extracellular matrix proteins, peptides, lipids and polysaccharides, have been employed for decades in biomedical science. Their excellent biocompatibility, biodegradability in the absence of toxic compound release, physiochemical properties that are similar to those of human tissues and reduced immunogenicity make them outstanding candidates to improve neural interface biocompatibility and long-term implantation safety. The objective of this review is to highlight progress and challenges concerning the impact of nature-derived materials on neural interface design. The use of these materials as biocompatible coatings and as building blocks of insulation materials for use in implantable neural interfaces is discussed. Moreover, future perspectives are presented to show the increasingly important uses of these materials for neural interface fabrication and their possible use for other applications in the framework of neural engineering.

scholarly journals Urban Geometry Optimization to Mitigate Climate Change: Towards Energy-Efficient Buildings

2020 ◽  
Vol 13 (1) ◽  
pp. 27
Author(s):  
Hatem Mahmoud ◽  
Ayman Ragab
Keyword(s):  
Climate Change ◽  
Heat Stress ◽  
Thermal Efficiency ◽  
Energy Demand ◽  
Building Blocks ◽  
Climate Projections ◽  
Climate Change Scenarios ◽  
Urban Geometry ◽  
Outdoor Spaces ◽  
The Impact

The density of building blocks and insufficient greenery in cities tend to contribute dramatically not only to increased heat stress in the built environment but also to higher energy demand for cooling. Urban planners should, therefore, be conscious of their responsibility to reduce energy usage of buildings along with improving outdoor thermal efficiency. This study examines the impact of numerous proposed urban geometry cases on the thermal efficiency of outer spaces as well as the energy consumption of adjacent buildings under various climate change scenarios as representative concentration pathways (RCP) 4.5 and 8.5 climate projections for New Aswan city in 2035. The investigation was performed at one of the most underutilized outdoor spaces on the new campus of Aswan University in New Aswan city. The potential reduction of heat stress was investigated so as to improve the thermal comfort of the investigated outdoor spaces, as well as energy savings based on the proposed strategies. Accordingly, the most appropriate scenario to be adopted to cope with the inevitable climate change was identified. The proposed scenarios were divided into four categories of parameters. In the first category, shelters partially (25–50% and 75%) covering the streets were used. The second category proposed dividing the space parallel or perpendicular to the existing buildings. The third category was a hybrid scenario of the first and second categories. In the fourth category, a green cover of grass was added. A coupling evaluation was applied utilizing ENVI-met v4.2 and Design-Builder v4.5 to measure and improve the thermal efficiency of the outdoor space and reduce the cooling energy. The results demonstrated that it is better to cover outdoor spaces with 50% of the overall area than transform outdoor spaces into canyons.

scholarly journals Electrochemical synthesis of biobased polymers and polymer building blocks from vanillin

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8970-8985
Author(s):  
Robin Kunkel ◽  
Volkmar M. Schmidt ◽  
Carsten Cremers ◽  
Dominik Müller ◽  
Detlef Schmiedl ◽  
...  
Keyword(s):  
Process Parameters ◽  
Current Density ◽  
Electrode Material ◽  
Electrochemical Synthesis ◽  
Building Blocks ◽  
Biobased Polymers ◽  
The Impact

Hydrovanilloin and polyvanillin were synthesized electrochemically investigating the impact of process parameters such as electrode material, charge and current density.

scholarly journals The Impact of No Child Left Behind on Students, Teachers, and Schools

2010 ◽  
Vol 2010 (2) ◽  
pp. 149-194 ◽  
Author(s):  
Thomas S. Dee ◽  
Brian A. Jacob
Keyword(s):  
No Child Left Behind ◽  
Left Behind ◽  
The Impact
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