Antarctic sea ice region as a source of biogenic organic nitrogen in aerosols

Dall'Osto, Manuel ... et al.-- 10 pages, 5 figuresClimate warming affects the development and distribution of sea ice, but at present the evidence of polar ecosystem feedbacks on climate through changes in the atmosphere is sparse. By means of synergistic atmospheric and oceanic measurements in the Southern Ocean near Antarctica, we present evidence that the microbiota of sea ice and sea ice-influenced ocean are a previously unknown significant source of atmospheric organic nitrogen, including low molecular weight alkyl-amines. Given the keystone role of nitrogen compounds in aerosol formation, growth and neutralization, our findings call for greater chemical and source diversity in the modelling efforts linking the marine ecosystem to aerosol-mediated climate effects in the Southern OceanThe cruise was funded by the Spanish Ministry of Economy through projects PEGASO (CTM2012-37615) and Bio-Nuc (CGL2013-49020-R), and by the EU though the FP7-PEOPLE-2013-IOF programme (Project number 624680, MANU – Marine Aerosol NUcleations). [...] The NUI Galway and ISAC-CNR Bologna groups acknowledge funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) project BACCHUS under grant agreement n° 603445. The work was further supported by the CNR (Italy) under AirSEaLab: Progetto Laboratori Congiunti. The National Centre for Atmospheric Science NCAS Birmingham group is funded by the UK Natural Environment Research Council. [...] CC, MFF and RA acknowledge funding from the Marine Institute, University of Plymouth to enable participation in PEGASOPeer Reviewe

Harnessing the Wisdom in Colloidal Chemistry to Make Stable Single-Atom Catalysts

Research on single‐atom catalysts (SACs), or atomically dispersed catalysts, has been quickly gaining momentum over the past few years. Although the unique electronic structure of singly dispersed atoms enables uncommon—sometimes exceptional—activities and selectivities for various catalytic applications, developing reliable and general procedures for preparing stable, active SACs in particular for applications under reductive conditions remains a major issue. Herein, the challenges associated with the synthesis of SACs are highlighted semiquantitatively and three stabilization techniques inspired by colloidal science including steric, ligand, and electrostatic stabilization are proposed. Some recent examples are discussed in detail to showcase the power of these strategies in the synthesis of stable SACs without compromising catalytic activity. The substantial further potential of steric, ligand, and electrostatic effects for developing SACs is emphasized. A perspective is given to point out opportunities and remaining obstacles, with special attention given to electrostatic stabilization where little is done so far. The stabilization strategies presented herein have a wide applicability in the synthesis of a series of new SACs with improved performances

Magnetic correlations in a layered iridate, Na2IrO3

This chapter examines the first uses of the word sadism at the end of the nineteenth century and the earlier visions of sexual cruelty as social violence that operated in psychiatric and criminological thought. In these texts, sadism stood as a sign for degeneration since fusions of sex and violence were imagined to belong in the barbarous stage of social evolution. In ‘civilized’ societies such desires could only be perverse. Early twentieth-century nationalist propaganda throughout Europe frequently invoked images of a barbarous ‘other’ whose brutal and cruel sexual desire threatened the virginity of a feminine icon of civilized nationhood

Transverse magnetic exchange springs in a DyFe2/YFe2 superlattice

Using a history-dependent method, it is possible to prepare magnetic superlattices, consisting of alternating hard and soft layers, in transverse exchange spring states. The procedure, which involves both physical rotation and magnetization routines, is illustrated using a (110)-oriented [DyFe 2(60) 15 multilayer film. In small applied fields, it is shown that the magnetic response of a transverse magnetic exchange spring is reversible. However, in fields of up to 14 T, the Dy moments are pulled up out of their local in-plane [001̄] minimum into an out-of-plane [100] (or equivalent [010]) axis. The reversible transverse exchange spring state is then lost. Thereafter, the magnetic loop is characterized by an irreversible out-of-plane magnetic exchange spring state. © 2012 American Physical Society

Magnetic reversal in a YFe2 dominated DyFe2/YFe2 multilayer film

Magnetic reversal in a (110)-oriented [DyFe 2 (60 Å)/YFe 2 (240 Å) × 15 multilayer film is investigated using magnetometry, micro-magnetic modeling, and element-specific soft x-ray magnetic circular dichroism. At temperatures between ∼60 and 120 K, the magnetic reversal involves a two-step process. It is shown that the reversal mechanism can be described as switching from an in-plane [001] reversed anti-ferromagnetic state, to an out-of-plane [100] transverse spring exchange state, and finally to an in-plane [001] magnetic exchange spring state. © 2012 American Institute of Physics