High‐performance carbon fibers prepared by continuous stabilization and carbonization of electron beam‐irradiated textile grade polyacrylonitrile fibers

The manufacturing of high‐performance carbon fibers (CFs) from low‐cost textile grade poly(acrylonitrile) (PAN) homo‐ and copolymers using continuous electron beam (EB) irradiation, stabilization, and carbonization on a kilogram scale is reported. The resulting CFs have tensile strengths of up to 3.1 ± 0.6 GPa and Young's moduli of up to 212 ± 9 GPa, exceeding standard grade CFs such as Toray T300. Additionally, the Weibull strength and modulus, the microstructure, and the morphology of these CFs are determined.Dralon Gmb

Electrophysiological assessment methodology of sensory processing dysfunction in schizophrenia and dementia of the Alzheimer type

Schizophrenia and Alzheimer’s disease impacts on various sensory processings are extensively reviewed in the present publication. This article describes aspects of a research project whose aim is to delineate the neurobiology that may underlie Social Withdrawal in Alzheimer’s disease, Schizophrenia and Major Depression. This is a European-funded IMI 2 project, identified as PRISM (Psychiatric Ratings using Intermediate Stratified Markers). This paper focuses specifically on the selected electrophysiological paradigms chosen based on a comprehensive review of all relevant literature and practical constraints. The choice of the electrophysiological biomarkers were fundamentality based their metrics and capacity to discriminate between populations. The selected electrophysiological paradigms are resting state EEG, auditory mismatch negativity, auditory and visual based oddball paradigms, facial emotion processing ERP’s and auditory steady-state response. The primary objective is to study the effect of social withdrawal on various biomarkers and endophenotypes found altered in the target populations. This has never been studied in relationship to social withdrawal, an important component of CNS diseases

Local and regional trends in Plio-Pleistocene δ18O records from benthic foraminifera

We present new orbital-resolution Pliocene-Pleistocene benthic stable oxygen isotope (δ18Ob) records from Ocean Drilling Program Sites 1264 and 1267, from Walvis Ridge in the Southeast Atlantic. We compare long-term (>250 kyr) interbasin δ18Ob-gradients between Pacific and North Atlantic regional stacks, as well as intra and interbasin gradients from the perspective of Walvis Ridge. The δ18Ob values from Sites 1264 and 1267 are almost always higher than deep North Atlantic and Pacific sites, with large gradients (>0.5‰) emerging abruptly at ∼2.4 Ma and persisting until ∼1.3 Ma. From this, we infer the presence of a new water mass, which resulted from the influence of dense, 18O-enriched Nordic sea overflow waters via the abyssal East Atlantic. Meanwhile, long-term average δ18Ob values in the North Atlantic appear to have remained within 0–0.25‰ lower than in the Pacific. However, the magnitude of this difference is sensitive to the inclusion of records from the equatorial West Atlantic. These results, together with constraints based on temperature, salinity, and density, suggest an influence of the seawater δ18O (δ18OSW) versus salinity relationship of source waters on δ18Ob values within the Atlantic. In particular, the abrupt emergence at ∼2.4 Ma of higher δ18Ob values at Sites 1264 and 1267, relative to North Atlantic records, appears to require a low-latitude surface water δ18OSW signal. This implies a connection between northward heat transport and deep water export into the abyssal East Atlantic. Hence, our results have implications for the interpretation of δ18Ob records and highlight the potential for δ18Ob to constrain deep Atlantic water mass sources and pathways during the Plio-Pleistocene

Paleoclimate, Paleoclimate history of the Arctic

Although the Arctic occupies less than 5% of the Earth's surface, it includes some of the strongest positive feedbacks in the climate system. Reconstructing the climate history of the Quaternary requires a suite of climate proxies that can be placed in a secure time frame. Most Arctic proxies reflect past summer temperatures, although a subset is sensitive to winter temperatures and/or precipitation. During the Quaternary, the Arctic has experienced a greater change in temperature, vegetation, and ocean surface characteristics than has any other Northern Hemisphere latitudinal band. Arctic temperature amplification is a consequence of several strong positive feedbacks. They include the fast feedbacks of snow and ice albedo, sea-ice insulation, vegetation, and permafrost, as well as a suite of slower responding feedbacks operating on glacial–interglacial timescales tied to the growth and decay of aerially extensive, thick continental ice sheets. Large changes in Arctic temperatures impact regions outside the Arctic through their proximal influence on the planetary energy balance and circulation of the Northern Hemisphere atmosphere and ocean, and with potential global impacts through changes in sea level, the release of greenhouse gases, and impacts on the ocean's meridional overturning circulation. Quantitative paleoclimate reconstructions for specific cold and warm times during the Quaternary suggest that Arctic temperature changes have been 3 to 4 times the corresponding hemispheric or globally averaged changes. This article provides a brief overview of climate changes leading up to the last ice age, then overviews the changes in Arctic climate during the Quaternary

Temperature and precipitation history of the Arctic

As the planet cooled from peak warmth in the early Cenozoic, extensive Northern Hemisphere ice sheets developed by 2.6 Ma ago, leading to changes in the circulation of both the atmosphere and oceans. From not, vert, similar2.6 to not, vert, similar1.0 Ma ago, ice sheets came and went about every 41 ka, in pace with cycles in the tilt of Earth’s axis, but for the past 700 ka, glacial cycles have been longer, lasting not, vert, similar100 ka, separated by brief, warm interglaciations, when sea level and ice volumes were close to present. The cause of the shift from 41 ka to 100 ka glacial cycles is still debated. During the penultimate interglaciation, not, vert, similar130 to not, vert, similar120 ka ago, solar energy in summer in the Arctic was greater than at any time subsequently. As a consequence, Arctic summers were not, vert, similar5 °C warmer than at present, and almost all glaciers melted completely except for the Greenland Ice Sheet, and even it was reduced in size substantially from its present extent. With the loss of land ice, sea level was about 5 m higher than present, with the extra melt coming from both Greenland and Antarctica as well as small glaciers. The Last Glacial Maximum (LGM) peaked not, vert, similar21 ka ago, when mean annual temperatures over parts of the Arctic were as much as 20 °C lower than at present. Ice recession was well underway 16 ka ago, and most of the Northern Hemisphere ice sheets had melted by 6 ka ago. Solar energy reached a summer maximum (9% higher than at present) not, vert, similar11 ka ago and has been decreasing since then, primarily in response to the precession of the equinoxes. The extra energy elevated early Holocene summer temperatures throughout the Arctic 1–3 °C above 20th century averages, enough to completely melt many small glaciers throughout the Arctic, although the Greenland Ice Sheet was only slightly smaller than at present. Early Holocene summer sea ice limits were substantially smaller than their 20th century average, and the flow of Atlantic water into the Arctic Ocean was substantially greater. As summer solar energy decreased in the second half of the Holocene, glaciers re-established or advanced, sea ice expanded, and the flow of warm Atlantic water into the Arctic Ocean diminished. Late Holocene cooling reached its nadir during the Little Ice Age (about 1250–1850 AD), when sun-blocking volcanic eruptions and perhaps other causes added to the orbital cooling, allowing most Arctic glaciers to reach their maximum Holocene extent. During the warming of the past century, glaciers have receded throughout the Arctic, terrestrial ecosystems have advanced northward, and perennial Arctic Ocean sea ice has diminished. Here we review the proxies that allow reconstruction of Quaternary climates and the feedbacks that amplify climate change across the Arctic. We provide an overview of the evolution of climate from the hot-house of the early Cenozoic through its transition to the ice-house of the Quaternary, with special emphasis on the anomalous warmth of the middle Pliocene, early Quaternary warm times, the Mid Pleistocene transition, warm interglaciations of marine isotope stages 11, 5e, and 1, the stage 3 interstadial, and the peak cold of the last glacial maximum