Sources and proxy potential of long chain alkyl diols in lacustrine environments

Long chain 1,13- and 1,15-alkyl diols form the base of a number of recently proposed proxies used for climate reconstruction. However, the sources of these lipids and environmental controls on their distribution are still poorly constrained. We have analyzed the long chain alkyl diol (LCD) composition of cultures of ten eustigmatophyte species, with three species from different families grown at various temperatures, to identify the effect of species composition and growth temperature on the LCD distribution. The results were compared with the LCD distribution of sixty-two lake surface sediments, and with previously reported LCD distributions from marine environments. The different families within the Eustigmatophyceae show distinct LCD patterns, with the freshwater family Eustigmataceae most closely resembling LCD distributions in both marine and lake environments. Unlike the other two eustigmatophyte families analyzed (Monodopsidaceae and Goniochloridaceae), C28 and C30 1,13-alkyl diols and C30 and C32 1,15-alkyl diols are all relatively abundant in the family Eustigmataceae, while the mono-unsaturated C32 1,15-alkyl diol was below detection limit. In contrast to the marine environment, LCD distributions in lakes did not show a clear relationship with temperature. The Long chain Diol Index (LDI), a proxy previously proposed for sea surface temperature reconstruction, showed a relatively weak correlation (R2 = 0.33) with mean annual air temperature used as an approximation for annual mean surface temperature of the lakes. A much-improved correlation (R2 = 0.74, p-value<0.001) was observed applying a multiple linear regression analysis between LCD distributions and lake temperatures reconstructed using branched tetraether lipid distributions. The obtained regression model provides good estimates of temperatures for cultures of the family Eustigmataceae, suggesting that algae belonging to this family have an important role as a source for LCDs in lacustrine environments, or, alternatively, that the main sources of LCDs are similarly affected by temperature as the Eustigmataceae. The results suggest that LCDs may have the potential to be applicable as a palaeotemperature proxy for lacustrine environments, although further calibration work is still required.

(Table 1.15) Composition of glassy basalts from the north part of the Bougault anomaly, Mid-Atlantic Ridge 15°N

Structure and composition of sub-surface bottom sediments from the southwest Barents Sea have been under study. The study has revealed heterogeneity of sediment structure resulted from temporal irregularity and variability of sedimentation processes. The study of the heavy minerals from 0.1-0.01 mm grain size fraction has shown prevalence of green hornblende, epidote, garnet, and ilmenite in all types of sediments; these minerals are the basis of terrigenous-mineralogical province. At the same time in different areas local terrigenous-mineralogical associations have been identified. Clay mineral composition of in the sediments was quite uniform: biotite, chlorite, hydromica, smectite. Despite this, a number of features indicating initial stages of clay mineral transformation has been identified. Differences in material composition and structure of the studied sediments are associated with rapid change in paleogeographic situation on the land - ice cover melting on the Kola Peninsula and subsequent Holocene climatic situation.

La Traca : semanari pa la gent de tro: Año I Número 1 - 15 noviembre 1884

Recurso electrónico. Valencia: BVNP, 2014

Electrophysiological evidence for a hyperpolarizing, galanin (1-15)-selective receptor on hippocampal CA3 pyramidal neurons

The effects of the 29-amino acid neuropeptide galanin [GAL (1–29)], GAL(1–15), GAL(1–16), and the GAL subtype 2 receptor agonist d-tryptophan2-GAL(1–29) were studied in the dorsal hippocampus in vitro with intracellular recording techniques. GAL(1–15) induced, in the presence of tetrodotoxin, a dose-dependent hyperpolarization in hippocampal CA3 neurons. Most of the GAL(1–15)-sensitive neurons did not respond to GAL(1–29), GAL(1–16), or d-tryptophan2-GAL(1–29). These results indicate the presence of a distinct, yet-to-be cloned GAL(1–15)-selective receptor on CA3 neurons in the dorsal hippocampus.

Revista moderna : Anno 1, n. 1 (15 maio 1897)

Impressa em papel couché. De acordo com Ana Luiza Martins em sua obra "Revistas em revista": "A Revista Moderna, impressa em Paris, em 1897, introduzia o que havia de mais avançado em periodismo, primando por elaboradas reportagens, coberturas de acontecimentos marcantes do tempo, geralmente ilustradas com desenhos tomados a partir dos acontecimentos, não se furtando ao sensacionalismo em voga."

Revista moderna : Anno 11, n. 1 (15 dez.1897)

Impressa em papel couché. De acordo com Ana Luiza Martins em sua obra "Revistas em revista": "A Revista Moderna, impressa em Paris, em 1897, introduzia o que havia de mais avançado em periodismo, primando por elaboradas reportagens, coberturas de acontecimentos marcantes do tempo, geralmente ilustradas com desenhos tomados a partir dos acontecimentos, não se furtando ao sensacionalismo em voga."

Does Europe Need a Common Foreign & Security Policy? CES Germany & Europe Working Papers, No. 06.1, 15 September, 1996

CFSP's performance is widely regarded as weak. Why did Europe's stance in world politics not improve with the Treaty of Maastricht? The article analyses the present policy approach and the institutionalist and militarystrategic reform proposals. It is argued that policy and proposals suffer from drawbacks leading to an uncomprehensive formulation of a Common Foreign and Security Policy. Both do not provide CFSP with a necessary strategy but instead largely duplicate existing organizations. Furthermore, they propose concepts that are not viable because member states do not agree on a common defense policy. In addition, they fail to offer answers adequate to today's challenges, which are not primarily military in nature. Instead, a socioeconomic security policy appears to be a more realistic option. It is necessary because no other organization provides it sufficiently; it is viable because member states could agree on iti and it is adequate because the stabilization of countries in Eastern Europe is best achieved by social and economic policy-and not by military deterrence.

US Democracy Promotion from Bush to Obama. EUSpring Working Paper No. 1, 15 April 2015

Throughout the twenty-first century the United States (U.S.) has attempted to balance its traditional national security interests, whilst also seeking to promote the long-term transformation of the Middle East and North Africa (MENA) towards democracy based on liberal values. With the September 11, 2001 terrorist attacks providing a catalyst for policy change, the U.S. has moved away from its twentieth-century policy of pursuing a regional status quo and instinctively balking at political change. Yet, the U.S. has not abandoned its reliance on autocratic regimes that cooperate on more immediate national security interests such as counter-terrorism, counter-proliferation, and the free-flow energy sources into the global market. Rather, U.S. democracy promotion in the MENA has become incremental by design and is characterized by its gradualist and often-collaborative nature. U.S. foreign policy in the MENA is, therefore, depicted by a cautious evolutionary stance rather than supporting revolutionary shifts in power.

Russian basic course : pronunciation dialogues 1-15 /

Russian and English.