Reconstruction of the Holocene monsoon climate variability in the Arabian Sea based on alkenone sea surface temperature, primary productivity and denitrification proxies

The Indian monsoon climate influences large parts of the world’s population. But relatively little is known about its decadal to centennial scale variation at time scales of societal relevance. The aim of this study was to reconstruct the Holocene history of summer and winter monsoon variability in high-resolution by analyzing sediment cores from different locations in the Arabian Sea (northern Indian Ocean). Oceanic properties and biogeochemical processes in the Arabian Sea, such as sea surface temperature (SST), primary productivity and the intensity of the mid-water oxygen minimum zone and water column denitrification are closely coupled to the seasonal monsoon cycle. While primary productivity and SST in the northwestern Arabian Sea are mainly impacted by upwelling processes associated with the summer monsoon, in the northeastern Arabian Sea off Pakistan low SST and high primary productivity are driven by the north-easterly winds of the winter monsoon. Based on this modern setting, I analyzed alkenone-derived SST changes together with proxies of primary productivity (organic carbon, carbonate/opal, δ15N) in a well-laminated sediment core from the Pakistan continental margin to establish a high-resolution record of winter monsoon strength for the late Holocene (chapter 3). Over the last 2400 years reconstructed SST decreased whereas productivity increased, reflecting a long-term trend of winter monsoon strengthening. A comparison of my winter monsoon record with records of summer monsoon strength shows that an inverse relationship of summer and winter monsoon strength exists in the Asian monsoon region over the late Holocene. The linked variation of summer and winter monsoon strength most likely was caused by shifts in the long-term latitudinal position of the Intertropical Convergence Zone (ITCZ), forced by changes in solar output. Reconstruction and comparison of alkenone-derived SST patterns from two sediment cores, one from the summer monsoon dominated northwestern Arabian Sea and one from the winter monsoon influenced northeastern Arabian Sea, reveal that this antagonistic behavior of summer and winter monsoon strength was also evident over the last 25,000 years (chapter 4). Strong upwelling at the coast of northern Oman reflects intensified summer monsoon activity during the early Holocene climate optimum, contemporaneous with a decline in winter monsoon strength as indicated by increasing SST off Pakistan. Strengthening of winter monsoon activity since the early Holocene was forced by a southward displacement of the ITCZ throughout the Holocene. The late Holocene alkenone-based SST record from the northeastern Arabian Sea shows a close correlation to decadal to centennial scale climate variability recorded on the Asian continent and the high-latitude Northern Hemisphere. Colder climate conditions (as observed during the Little Ice Age) increase the strength of northeast monsoonal winds and lower SST in the northeastern Arabian Sea. Chapter 5 deals with the temporal and spatial variability of the Arabian Sea oxygen minimum zone (OMZ) over the Holocene and its relation to varying monsoon strength. Proxies of mid-water oxygenation and southwest monsoon strength were analyzed in a sediment core from the northern Oman Margin representing the late and mid Holocene. The comparison of my δ15N and Mn/Al records with other records of denitrification and oxygenation from the northern Arabian Sea shows that the location of the core OMZ has shifted from the northwest (early Holocene) to the northeast (late Holocene) throughout the Holocene. This shift was caused by a reorganization of mid-water circulation (oxygen supply) in the northern Arabian Sea due to sea level rise together with spatial differences in the response of primary productivity (oxygen demand) to varying monsoon activity

First Test of Lorentz Invariance in the Weak Decay of Polarized Nuclei

A new test of Lorentz invariance in the weak interactions has been made by searching for variations in the decay rate of spin-polarized 20Na nuclei. This test is unique to Gamow-Teller transitions, as was shown in the framework of a recently developed theory that assumes a Lorentz symmetry breaking background field of tensor nature. The nuclear spins were polarized in the up and down direction, putting a limit on the amplitude of sidereal variations of the form |(\Gamma_{up} - \Gamma_{down})| / (\Gamma_{up} + \Gamma_{down}) < 3 * 10^{-3}. This measurement shows a possible route toward a more detailed testing of Lorentz symmetry in weak interactions.Comment: 11 pages, 6 figure

South African NGOs and the public sphere: between popular movements and partnerships for development.

This article examines the widespread notion that post-apartheid democracy can be deepened and civil society strengthened by NGO activities in the sphere of public debate and participation. I focus on a number of interrelated processes which I argue may compromise NGOs' ability to expand the public sphere: first, donors' overwhelming focus on NGOs as the sole representative of civil society may contribute to a homogenous and institutionalised public sphere; second, the tendency for NGOs to be drawn into partnerships with government bodies and corporate sponsors casts doubt on their ability to open up spaces for critical public debate. By directing attention to popular movements as potentially offering a site for the production of critique, NGOs' relationships to such movements are examined. It is argued that attention must be paid to the processes of NGO-isation and reformism by which NGOs themselves come to define what civil society should be and may consequently contain counterpublic spheres

A gas cell for stopping, storing and polarizing radioactive particles

A radioactive beam of 20Na is stopped in a gas cell filled with Ne gas. The stopped particles are polarized by optical pumping. The degree of polarization that can be achieved is studied. A maximum polarization of 50% was found. The dynamic processes in the cell are described with a phenomenological model.Comment: 16 pages, 6 figure

‘The Rest is Silence’:Psychogeography, Soundscape and Nostalgia in Pat Collins’ Silence

Guy Debord defines the term psychogeography as 'the study of the precise laws and specific effects of the geographical environment, consciously organised or not, on the emotions and behaviour of individuals' (Debord 1955: 23). Similar to the belief of psychogeographers that the geography of an environment has a psychological effect on the human mind, proponents of acoustic ecology such as R. Murray Schafer hold that humans are affected by the sound of the environment in which they find themselves. Further to this, they examine the extent to which soundscapes can be shaped by human behaviour. Recently a body of Irish films has emerged that directly engages with the Irish soundscape and landscape on a psychogeographical level. Rather than using landscape as a physical space for the locus of action, these representations of the Irish landscape allow for an engagement with the aesthetic effects of the geographical landscape as a reflection of the psychological states of the protagonists. Bearing this in mind, this article examines how Silence (Collins 2012) arguably demonstrates the most overt and conscious incursion into this area to date. It specifically interrogates how the filmic representation of the psychogeography and soundscape of the Irish rural landscape can serve to express emotion, alienation and nostalgia, thus confronting both the Irish landscape and the weight of its associated history

Tuning the Morphological Appearance of Iron(III) Fumarate: Impact on Material Characteristics and Biocompatibility

Iron(III) fumarate materials are well suited for biomedical applications as they feature biocompatible building blocks, porosity, chemical functionalizability, and magnetic resonance imaging (MRI) activity. The synthesis of these materials however is difficult to control, and it has been challenging to produce monodisperse particle sizes and morphologies that are required in medical use. Here, we report the optimization of iron(III) fumarate nano- and microparticle synthesis by surfactant-free methods, including room temperature, solvothermal, microwave, and microfluidic conditions. Four variants of iron(III) fumarate with distinct morphologies were isolated and are characterized in detail. Structural characterization shows that all iron(III) fumarate variants exhibit the metal–organic framework (MOF) structure of MIL-88A. Nanoparticles with a diameter of 50 nm were produced, which contain crystalline areas not exceeding 5 nm. Solvent-dependent swelling of the crystalline particles was monitored using in situ X-ray diffraction. Cytotoxicity experiments showed that all iron(III) fumarate variants feature adequate biotolerability and no distinct interference with cellular metabolism at low concentrations. Magnetic resonance relaxivity studies using clinical MRI equipment, on the other hand, proved that the MRI contrast characteristics depend on particle size and morphology. All in all, this study demonstrates the possibility of tuning the morphological appearance of iron(III) fumarate particles and illustrates the importance of optimizing synthesis conditions for the development of new biomedical materials

Recent Asian origin of chytrid fungi causing global amphibian declines

Globalized infectious diseases are causing species declines worldwide, but their source often remains elusive. We used whole-genome sequencing to solve the spatiotemporal origins of the most devastating panzootic to date, caused by the fungus Batrachochytrium dendrobatidis, a proximate driver of global amphibian declines. We traced the source of B. dendrobatidis to the Korean peninsula, where one lineage, BdASIA-1, exhibits the genetic hallmarks of an ancestral population that seeded the panzootic. We date the emergence of this pathogen to the early 20th century, coinciding with the global expansion of commercial trade in amphibians, and we show that intercontinental transmission is ongoing. Our findings point to East Asia as a geographic hotspot for B. dendrobatidis biodiversity and the original source of these lineages that now parasitize amphibians worldwide

Development and worldwide use of non-lethal, and minimal population-level impact, protocols for the isolation of amphibian chytrid fungi

© The Author(s) 2018.Parasitic chytrid fungi have emerged as a significant threat to amphibian species worldwide, necessitating the development of techniques to isolate these pathogens into culture for research purposes. However, early methods of isolating chytrids from their hosts relied on killing amphibians. We modified a pre-existing protocol for isolating chytrids from infected animals to use toe clips and biopsies from toe webbing rather than euthanizing hosts, and distributed the protocol to researchers as part of the BiodivERsA project RACE; here called the RML protocol. In tandem, we developed a lethal procedure for isolating chytrids from tadpole mouthparts. Reviewing a database of use a decade after their inception, we find that these methods have been applied across 5 continents, 23 countries and in 62 amphibian species. Isolation of chytrids by the non-lethal RML protocol occured in 18% of attempts with 207 fungal isolates and three species of chytrid being recovered. Isolation of chytrids from tadpoles occured in 43% of attempts with 334 fungal isolates of one species (Batrachochytrium dendrobatidis) being recovered. Together, these methods have resulted in a significant reduction and refinement of our use of threatened amphibian species and have improved our ability to work with this group of emerging pathogens.T.W.J.G., M.C.F., D.S.S., A.L., E.C., F.C.C., J.B., A.A.C., C.M., F.S., B.R.S., S.O., were supported through the Biodiversa project RACE: Risk Assessment of Chytridiomycosis to European Amphibian Biodiversity (NERC standard grant NE/K014455/1 and NE/E006701/1; ANR-08-BDVA-002-03). M.C.F., J.S., C.W., P.G. were supported by the Leverhulme Trust (RPG-2014-273), M.C.F., A.C., C.W. were supported by the Morris Animal Foundation. J.V. was supported by the Bolyai János Research Grant of the Hunagrian Academy of Sciences (BO/00597/14). F.G. and D.G. were supported by the Conservation Leadership Programme Future Conservationist Award. C.S.A. was supported by Fondecyt (No. 1181758). M.C.F. and A.C. were supported by. Mohamed bin Zayed Species Conservation Fund Project (152510704). GMR held a doctoral scholarship (SFRH/ BD/69194/2010) from Fundação para a Ciência e a Tecnologia. L.F.T., C.L., L.P.R. K.R.Z., T.Y.J., T.S.J. were supported by São Paulo Research Foundation (FAPESP #2016/25358-3), the National Counsel of Technological and Scientifc Development (CNPq #300896/2016–6) and a Catalyzing New International Collaborations grant from the United States NSF (OISE-1159513). C.S.A. was supported by Fondecyt (No. 1181758). T.M.D. was supported by the Royal Geographical Society and the Royal Zoological Society of Scotland. B.W. was supported by the National Research Foundation of Korea (2015R1D1A1A01057282).Peer Reviewe