ALBERT

Beschreibung: The reaction of 2-(1,2,3,4-tetrahydronapthalen-1-ylidene)hydrazinecarbothioamide (TTSC) with pyrazine-2,3,5,6-tetracarbonitrile (tetracyanopyrazine, TCNP) yields the title 2:1 charge-transfer adduct, 2C11H12N3S·C6N8. The complete TCNP molecule is generated by a crystallographic inversion centre and the non-aromatic ring in the TTSC molecule adopts an envelope conformation with a methylene C atom as the flap. In the crystal, the thiosemicarbazone molecules are connected through inversion-related pairs of N—H...S interactions, building a polymeric chain along the b-axis direction. The TCNP molecules are embedded in the structure, forming TTSC–TCNP–TTSC stacks with the aromatic rings of TTSC and the molecular plane of TCNP in a parallel arrangement [centroid–centroid distance = 3.5558 (14) Å]. Charge-transfer (CT) via π-stacking is indicated by a CT band around 550 cm−1 in the single-crystal absorption spectrum.

Beschreibung: The atomic nucleus is composed of two different kinds of fermions: protons and neutrons. If the protons and neutrons did not interact, the Pauli exclusion principle would force the majority of fermions (usually neutrons) to have a higher average momentum. Our high-energy electron-scattering measurements using (12)C, (27)Al, (56)Fe, and (208)Pb targets show that even in heavy, neutron-rich nuclei, short-range interactions between the fermions form correlated high-momentum neutron-proton pairs. Thus, in neutron-rich nuclei, protons have a greater probability than neutrons to have momentum greater than the Fermi momentum. This finding has implications ranging from nuclear few-body systems to neutron stars and may also be observable experimentally in two-spin-state, ultracold atomic gas systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hen, O -- Sargsian, M -- Weinstein, L B -- Piasetzky, E -- Hakobyan, H -- Higinbotham, D W -- Braverman, M -- Brooks, W K -- Gilad, S -- Adhikari, K P -- Arrington, J -- Asryan, G -- Avakian, H -- Ball, J -- Baltzell, N A -- Battaglieri, M -- Beck, A -- May-Tal Beck, S -- Bedlinskiy, I -- Bertozzi, W -- Biselli, A -- Burkert, V D -- Cao, T -- Carman, D S -- Celentano, A -- Chandavar, S -- Colaneri, L -- Cole, P L -- Crede, V -- D'Angelo, A -- De Vita, R -- Deur, A -- Djalali, C -- Doughty, D -- Dugger, M -- Dupre, R -- Egiyan, H -- El Alaoui, A -- El Fassi, L -- Elouadrhiri, L -- Fedotov, G -- Fegan, S -- Forest, T -- Garillon, B -- Garcon, M -- Gevorgyan, N -- Ghandilyan, Y -- Gilfoyle, G P -- Girod, F X -- Goetz, J T -- Gothe, R W -- Griffioen, K A -- Guidal, M -- Guo, L -- Hafidi, K -- Hanretty, C -- Hattawy, M -- Hicks, K -- Holtrop, M -- Hyde, C E -- Ilieva, Y -- Ireland, D G -- Ishkanov, B I -- Isupov, E L -- Jiang, H -- Jo, H S -- Joo, K -- Keller, D -- Khandaker, M -- Kim, A -- Kim, W -- Klein, F J -- Koirala, S -- Korover, I -- Kuhn, S E -- Kubarovsky, V -- Lenisa, P -- Levine, W I -- Livingston, K -- Lowry, M -- Lu, H Y -- MacGregor, I J D -- Markov, N -- Mayer, M -- McKinnon, B -- Mineeva, T -- Mokeev, V -- Movsisyan, A -- Munoz Camacho, C -- Mustapha, B -- Nadel-Turonski, P -- Niccolai, S -- Niculescu, G -- Niculescu, I -- Osipenko, M -- Pappalardo, L L -- Paremuzyan, R -- Park, K -- Pasyuk, E -- Phelps, W -- Pisano, S -- Pogorelko, O -- Price, J W -- Procureur, S -- Prok, Y -- Protopopescu, D -- Puckett, A J R -- Rimal, D -- Ripani, M -- Ritchie, B G -- Rizzo, A -- Rosner, G -- Roy, P -- Rossi, P -- Sabatie, F -- Schott, D -- Schumacher, R A -- Sharabian, Y G -- Smith, G D -- Shneor, R -- Sokhan, D -- Stepanyan, S S -- Stepanyan, S -- Stoler, P -- Strauch, S -- Sytnik, V -- Taiuti, M -- Tkachenko, S -- Ungaro, M -- Vlassov, A V -- Voutier, E -- Walford, N K -- Wei, X -- Wood, M H -- Wood, S A -- Zachariou, N -- Zana, L -- Zhao, Z W -- Zheng, X -- Zonta, I -- Jefferson Lab CLAS Collaboration -- New York, N.Y. -- Science. 2014 Oct 31;346(6209):614-7. doi: 10.1126/science.1256785. Epub 2014 Oct 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Tel Aviv University, Tel Aviv 69978, Israel. or.chen@mail.huji.ac.il. ; Florida International University, Miami, FL 33199, USA. ; Old Dominion University, Norfolk, VA 23529, USA. ; Tel Aviv University, Tel Aviv 69978, Israel. ; Universidad Tecnica Federico Santa Maria, Casilla 110-V Valparaiso, Chile. Yerevan Physics Institute, 375036 Yerevan, Armenia. ; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA. ; Universidad Tecnica Federico Santa Maria, Casilla 110-V Valparaiso, Chile. ; Massachusetts Institute of Technology, Cambridge, MA 02139, USA. ; Argonne National Laboratory, Argonne, IL 60439, USA. ; Yerevan Physics Institute, 375036 Yerevan, Armenia. ; Commissariat a l'Energie Atomique et aux Energies Alternatives, Centre de Saclay, Irfu/Service de Physique Nucleaire, 91191 Gif-sur-Yvette, France. ; Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Genova, 16146 Genova, Italy. ; Tel Aviv University, Tel Aviv 69978, Israel. Nuclear Research Center Negev, P.O. Box 9001, Beer-Sheva 84190, Israel. ; Institute of Theoretical and Experimental Physics, Moscow, 117259, Russia. ; Fairfield University, Fairfield, CT 06824, USA. ; University of South Carolina, Columbia, SC 29208, USA. ; Ohio University, Athens, OH 45701, USA. ; INFN, Sezione di Roma Tor Vergata, 00133 Rome, Italy. ; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA. Idaho State University, Pocatello, ID 83209, USA. Catholic University of America, Washington, DC 20064, USA. ; Florida State University, Tallahassee, FL 32306, USA. ; INFN, Sezione di Roma Tor Vergata, 00133 Rome, Italy. Universita di Roma Tor Vergata, 00133 Rome, Italy. ; University of South Carolina, Columbia, SC 29208, USA. University of Iowa, Iowa City, IA 52242, USA. ; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA. Christopher Newport University, Newport News, VA 23606, USA. ; Arizona State University, Tempe, AZ 85287-1504, USA. ; Institut de Physique Nucleaire ORSAY, Orsay, France. ; University of South Carolina, Columbia, SC 29208, USA. Skobeltsyn Institute of Nuclear Physics, Lomonosov, Russia. ; Idaho State University, Pocatello, ID 83209, USA. ; University of Richmond, Richmond, VA 23173, USA. ; College of William and Mary, Williamsburg, VA 23187-8795, USA. ; Florida International University, Miami, FL 33199, USA. Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA. ; University of Virginia, Charlottesville, VA 22901, USA. ; University of New Hampshire, Durham, NH 03824-3568, USA. ; University of South Carolina, Columbia, SC 29208, USA. The George Washington University, Washington, DC 20052, USA. ; University of Glasgow, Glasgow G12 8QQ, UK. ; Skobeltsyn Institute of Nuclear Physics, Lomonosov, Russia. ; University of Connecticut, Storrs, CT 06269, USA. ; Idaho State University, Pocatello, ID 83209, USA. Norfolk State University, Norfolk, VA 23504, USA. ; Kyungpook National University, Daegu 702-701, Republic of Korea. ; Catholic University of America, Washington, DC 20064, USA. ; INFN, Sezione di Ferrara, 44100 Ferrara, Italy. ; Carnegie Mellon University, Pittsburgh, PA 15213, USA. ; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA. Institut de Physique Nucleaire ORSAY, Orsay, France. Moscow State University, Moscow, 119234, Russia. ; James Madison University, Harrisonburg, VA 22807, USA. ; INFN, Sezione di Ferrara, 44100 Ferrara, Italy. Universita di Ferrara, 44122 Ferrara, Italy. ; Yerevan Physics Institute, 375036 Yerevan, Armenia. University of New Hampshire, Durham, NH 03824-3568, USA. ; Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA. Kyungpook National University, Daegu 702-701, Republic of Korea. ; INFN, Laboratori Nazionali di Frascati, 00044 Frascati, Italy. ; California State University, Dominguez Hills, Carson, CA 90747, USA. ; Old Dominion University, Norfolk, VA 23529, USA. University of Virginia, Charlottesville, VA 22901, USA. ; The George Washington University, Washington, DC 20052, USA. ; Edinburgh University, Edinburgh EH9 3JZ, UK. ; Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA. ; Universita di Genova, 16146 Genova, Italy. ; Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier, CNRS/IN2P3, Institut National Polytechnique, Grenoble, France. ; University of South Carolina, Columbia, SC 29208, USA. Canisius College, Buffalo, NY 14208, USA. ; University of New Hampshire, Durham, NH 03824-3568, USA. Edinburgh University, Edinburgh EH9 3JZ, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25323697" target="_blank"〉PubMed〈/a〉

Beschreibung: The reaction of 2-(1,2,3,4-tetrahydronapthalen-1-ylidene)hydrazinecarbothioamide (TTSC) with pyrazine-2,3,5,6-tetracarbonitrile (tetracyanopyrazine, TCNP) yields the title 2:1 charge-transfer adduct, 2C11H12N3S·C6N8. The complete TCNP molecule is generated by a crystallographic inversion centre and the non-aromatic ring in the TTSC molecule adopts an envelope conformation with a methylene C atom as the flap. In the crystal, the thiosemicarbazone molecules are connected through inversion-related pairs of N—H...S interactions, building a polymeric chain along theb-axis direction. The TCNP molecules are embedded in the structure, forming TTSC–TCNP–TTSC stacks with the aromatic rings of TTSC and the molecular plane of TCNP in a parallel arrangement [centroid–centroid distance = 3.5558 (14) Å]. Charge-transfer (CT)viaπ-stacking is indicated by a CT band around 550 cm−1in the single-crystal absorption spectrum.

Beschreibung: Here, we present results from sediments collected in the Argentine Basin, a non-steady state depositional marine system characterized by abundant oxidized iron within methane-rich layers due to sediment reworking followed by rapid deposition. Our comprehensive inorganic data set shows that iron reduction in these sulfate and sulfide-depleted sediments is best explained by a microbially mediated process—implicating anaerobic oxidation of methane coupled to iron reduction (Fe-AOM) as the most likely major mechanism. Although important in many modern marine environments, iron-driven AOM may not consume similar amounts of methane compared with sulfate-dependent AOM. Nevertheless, it may have broad impact on the deep biosphere and dominate both iron and methane cycling in sulfate-lean marine settings. Fe-AOM might have been particularly relevant in the Archean ocean, 〉2.5 billion years ago, known for its production and accumulation of iron oxides (in iron formations) in a biosphere likely replete with methane but low in sulfate. Methane at that time was a critical greenhouse gas capable of sustaining a habitable climate under relatively low solar luminosity, and relationships to iron cycling may have impacted if not dominated methane loss from the biosphere.

Beschreibung: The Polar Regions play an important role in the global processes of our planet, from climate change to sea level rise, protection from UV (ultraviolet) radiation to uptake of carbon dioxide. In addition, their scientific importance, extraordinary beauty and adventurous history provide perfect ingredients for both education and public outreach.Polar examples provide an excellent way to transmit basic concepts about a wide range of STEM (science, technology, engineering and mathematics) disciplines. The IPY (International Polar Year) brought educators and scientists together and provided the incentive for the formation of the PEI (Polar Educators International), an organization encouraging the exchange of ideas between educators and researchers and enhancement of the profile of polar education on the international scene. Educators must be adequately informed about current scientific polar research and have the confidenceto teach it to students. Scientists have the knowledge and data to explain these complexities, but may lack the communication skills to make the subject accessible to non-technical audiences. The development of this new network between polar educators and scientists has the potential to break down walls that restrict international collaboration and understanding, provide educators with topical and reliable information and share best practices internationally in an effective way.

Beschreibung: Since 2012, 60 lakes in northern Alaska have been instrumented under the auspices of CALON, a project designed to document landscape-scale variability in physical and biogeochemical processes of Arctic lakes in permafrost terrain. The network has ten observation nodes along two latitudinal transects extending from the Arctic Ocean inland some 200 km to the Brooks Range foothills. At each node, a meteorological station is deployed, and six representative lakes of differing area and depth are instrumented and sampled at different intensity levels to collect basic field measurements. In April, sensors measuring water temperature and depth are deployed through the ice in each lake, ice and snow thickness recorded, and water samples are collected. Data are downloaded, lakes re-sampled, and bathymetric surveys are conducted in August. In 2014, the snow cover on inland lakes was thinner than in previous years but thicker on lakes located near the coast. Lake ice was generally thinner near the coast, but the difference diminished inland. Winters (Oct-March) have been progressively warmer over the 3-year period, which partially explains the thinner lake ice that formed in 2013-14. Lakes are typically well–mixed and largely isothermal, with minor thermal stratification occurring in deeper lakes during calm, sunny periods. These regional lake and meteorological data sets, used in conjunction with satellite imagery, supports the wind-driven lake circulation model for the origin of thermokarst lakes. Results of biogeochemical analyses of lake waters generally show notably higher concentrations of cations/anions, chromophoric dissolved organic matter, and chlorophyll-a during April as compared with August. Dissolved methane concentrations are also much higher under ice than in open water during summer, although all lakes are a source of atmospheric methane. Interviews with indigenous elders in Anaktuvuk Pass indicate that mountain lakes are drying up. During the 2014 breakup period, 350 entrants participated in the 2nd Annual Toolik Lake Ice Classic including elementary school children, the general public, and international researchers. Ice off occurred on 23 June, and 11 people correctly guessed this day. All field data is archived at A-CADIS, and further information is at www.arcticlakes.org.

Beschreibung: Climate warming in the Arctic may result in release of carbon dioxide and/or methane from thawing permafrost soils, resulting in a positive feedback to warming. Permafrost thaw may also result in release of methane from previously trapped natural gas. The Arctic landscape is approximately 50% covered by shallow permafrost lakes, and these environments may serve as bellwethers for climate change – carbon cycle feedbacks, since permafrost thaw is generally deeper under lakes than tundra soils. Since 2011, the Circum-Arctic Lakes Observation Network (CALON) project has documented landscape-scale variability in physical and biogeochemical processes of Arctic lakes in permafrost terrain, including carbon cycle feedbacks to climate warming. Here we present a dataset of concentrations, isotope ratios (13C and 2H), and atmospheric fluxes of methane from lakes in Arctic Alaska. Concentrations of methane in lake water ranged from 0.3 to 43 micrograms per liter, or between 6 and 750 times supersaturated with respect to air. Isotopic measurements of dissolved methane indicated that most of the lakes had methane derived from anaerobic organic matter decomposition, but that some lakes may have a small source of methane from fossil fuel sources such as natural gas or coal beds. Concurrent measurements of methane fluxes and dissolved methane concentrations in summer of 2014 will aid in translating routine dissolved measurements into fluxes, and will also elucidate the relative importance of diffusive versus ebulliative fluxes. It is essential that measurements of methane emissions from Arctic lakes be continued long-term to determine whether methane emissions are on the rise, and whether warming of the lakes leads to increased venting of fossil fuel methane from enhanced thaw of permafrost beneath the lakes.