Photosynthetic maximum quantum yield increases are an essential component of the Southern Ocean phytoplankton response to iron

It is well established that an increase in iron supply causes an increase in total oceanic primary production in many regions, but the physiological mechanism driving the observed increases has not been clearly identified. The Southern Ocean iron enrichment experiment, an iron fertilization experiment in the waters closest to Antarctica, resulted in a 9-fold increase in chlorophyll (Chl) concentration and a 5-fold increase in integrated primary production. Upon iron addition, the maximum quantum yield of photosynthesis (phi(m)) rapidly doubled, from 0.011 to 0.025 mol C.mol quanta(-1). Paradoxically, this increase in light-limited productivity was not accompanied by a significant increase in light-saturated productivity (P-max(b)). P-max(b) maximum Chl normalized productivity, was 1.34 mg C.mg Chl(-1).h(-1) outside and 1.49 mg C.mg Chl(-1)-h(-1) inside the iron-enriched patch. The importance of phi(m) as compared with P-max(b) in controlling the biological response to iron addition has vast implications for understanding the ecological response to iron. We show that an iron-driven increase in phi(m) is the proximate physiological mechanism affected by iron addition and can account for most of the increases in primary production. The relative importance of phi(m) over P-max(b) in this iron-fertilized bloom highlights the limitations of often-used primary productivity algorithms that are driven by estimates of P-max(b) but largely ignore variability in phi(m) and light-limited productivity. To use primary productivity models that include variability in iron supply in prediction or forecasting, the variability of light-limited productivity must be resolved

2-(2-Methoxy­phen­yl)butane­dinitrile

In the title compound, C11H10N2O, the butane­dinitrile unit adopts a synclinal conformation. The crystal packing is stabilized by weak inter­molecular C—H⋯N hydrogen bonding

Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: An example from the Paulsens Mine, Southern Pilbara Craton

Paulsens is a mesothermal orogenic gold deposit located in the Wyloo Inlier on the southern margin of the Pilbara craton of Western Australia. Gold occurs in quartz-sulfide veins hosted within a folded and faulted gabbro dike, from which baddeleyite yields a U-Pb crystallization age of 2701 ± 11 Ma. Monazite and xenotime in the veins and from hydrothermally altered country rocks yield three distinct U-Pb dates of ca. 2400, 1730, and 1680 Ma. Textural relationships between euhedral xenotime and pyrite with rounded native gold inclusions from within the quartz-sulfide veins show that the primary gold mineralization was synchronous with xenotime crystallization at 2403 ± 5 Ma, and coeval with pervasive alteration of the host rocks, which yield monazite ages of 2398 ± 37 and 2403 ± 38 Ma. Regional-scale hydrothermal events at ca. 1730 and 1680 Ma are linked to the growth of monazite within phyllitic rocks at 1730 ± 28 and 1721 ± 32 Ma, carbonate veining at 1655 ± 37 Ma, and gold remobilization or introduction of new gold at 1680 ± 9 Ma. The ca. 2400 Ma age for mineralization and hydrothermal alteration does not correspond with any known deformation event in the region, indicating a significantly different and more complicated low-temperature tectonothermal evolution for the southern Pilbara region than previously recognized. The in situ secondary ion mass spectrometry dating of monazite and xenotime employed here will lead to better targeting of orogenic gold deposits in the northern Capricorn Orogen, and these techniques can be utilized for orogenic gold exploration worldwide

Phi meson production in relativistic heavy ion collisions

Within a multiphase transport model we study phi meson production in relativistic heavy ion collisions from both superposition of initial multiple proton-proton interactions and the secondary collisions in the produced hadronic matter. The yield of phi mesons is then reconstructed from their decaying product of either the kaon-antikaon pairs or the dimuon pairs. Since the kaon-antikaon pairs at midrapidity with low transverse momenta are predominantly rescattered or absorbed in the hadronic medium, they can not be used to reconstruct the phi meson and lead thus to a smaller reconstructed phi meson yield than that reconstructed from the dimuon channel. With in-medium mass modifications of kaons and phi mesons, the phi yield from dimuons is further enhanced compared to that from the kaon-antikaon pairs. The model result is compared with the experimental data at the CERN/SPS and RHIC energies and its implications to quark-gluon plasma formation are discussed.Comment: Revised version, to appear in Nucl. Phys.

The complexity of sediment recycling as revealed by common Pb isotopes in K-feldspar

© 2018 China University of Geosciences (Beijing) and Peking University. Detrital zircon U–Pb geochronology has become the gold standard in evaluating source to sink relationships in sedimentary basins. However, the physical and chemical robustness of zircon, which make it such a useful mineral for provenance studies, is also a hindrance as zircon can be recycled through numerous sedimentary basins, thus obscuring the first cycle source to sink relationship. An elegant approach to addressing this potential issue is to compare the Pb isotope composition of detrital K-feldspar, a mineral which is unlikely to survive more than one erosion-transport-deposition cycle, with that of magmatic K-feldspar from potential basement source terranes. Here we present new in situ Pb isotope data on detrital K-feldspar from two Proterozoic arkosic sandstones from Western Australia, and magmatic K-feldspar grains from potential igneous source rocks, as inferred by the age and Hf isotope composition of detrital zircon grains. The data indicate that the detrital zircon and K-feldspar grains could not have been liberated from the same source rocks, and that the zircon has most likely been recycled through older sedimentary basins. These results provide a more complete understanding of apparently simple source to sink relationships in this part of Proterozoic Western Australia

The birth of the Malaysian society for music in medicine: a concerted move to promote the use of music for therapeutic purposes

Malaysia is a multi-cultural society and the resulting myriad forms of music played in the nation are an ethnomusicologist’s haven. A simple cross-sample taken across the different kinds of music available reflects a diverse range reflective of much of the Asian region as a whole. Music medicine has existed for as long as the indigenous tribes have lived in the region. Formalized music therapy started in Malaysia approximately two decades ago by way of Western trained music therapists and is still in its infancy in therapeutic usage. As allopathic practitioners increasingly develop an evidence-based holistic mindset to complementary healing modalities, it is hoped that the use of music for therapeutic purposes will increase over time, and be localized for a population that blends Western, Chinese, Indian and indigenous healing systems. Efforts are made to conduct research using music-based intervention to provide evidence for integration of music medicine into Malaysian healthcare

Spot the Difference-Development of a Syndrome Based Protein Microarray for Specific Serological Detection of Multiple Flavivirus Infections in Travelers

Background The family Flaviviridae, genus Flavivirus, holds many of the world’s most prevalent arboviral diseases that are also considered the most important travel related arboviral infections. In most cases, flavivirus diagnosis in travelers is primarily based on serology as viremia is often low and typically has already been reduced to undetectable levels when symptoms set in and patients seek medical attention. Serological differentiation between flaviviruses and the false-positive results caused by vaccination and cross-reactivity among the different species, are problematic for surveillance and diagnostics of flaviviruses. Their partially overlapping geographic distribution and symptoms, combined with increase in travel, and preexisting antibodies due to flavivirus vaccinations, expand the need for rapid and reliable multiplex diagnostic tests to supplement currently used methods. Goal We describe the development of a multiplex serological protein microarray using recombinant NS1 proteins for detection of medically important viruses within the genus Flavivirus. Sera from clinical flavivirus patients were used for primary development of the protein microarray. Results Results show a high IgG and IgM sensitivity and specificity for individual NS1 antigens, and limited cross reactivity, even within serocomplexes. In addition, the serology based on this array allows for discrimination between infection and vaccination response for JEV vaccine, and no cross-reactivity with TBEV and YFV vaccine induced antibodies when testing for antibodies to other flaviviruses. Conclusion Based on these data, multiplex NS1-based protein microarray is a promising tool for surveillance and diagnosis of flaviviruses.

Plasmon-phonon coupling in large-area graphene dot and antidot arrays

Nanostructured graphene on SiO2 substrates pave the way for enhanced light-matter interactions and explorations of strong plasmon-phonon hybridization in the mid-infrared regime. Unprecedented large-area graphene nanodot and antidot optical arrays are fabricated by nanosphere lithography, with structural control down to the sub-100 nanometer regime. The interaction between graphene plasmon modes and the substrate phonons is experimentally demonstrated and structural control is used to map out the hybridization of plasmons and phonons, showing coupling energies of the order 20 meV. Our findings are further supported by theoretical calculations and numerical simulations.Comment: 7 pages including 6 figures. Supporting information is available upon request to author

Pervasive iron limitation at subsurface chlorophyll maxima of the California Current

Subsurface chlorophyll maximum layers (SCMLs) are nearly ubiquitous in stratified water columns and exist at horizontal scales ranging from the submesoscale to the extent of oligotrophic gyres. These layers of heightened chlorophyll and/or phytoplankton concentrations are generally thought to be a consequence of a balance between light energy from above and a limiting nutrient flux from below, typically nitrate (NO3). Here we present multiple lines of evidence demonstrating that iron (Fe) limits or with light colimits phytoplankton communities in SCMLs along a primary productivity gradient from coastal to oligotrophic offshore waters in the southern California Current ecosystem. SCML phytoplankton responded markedly to added Fe or Fe/light in experimental incubations and transcripts of diatom and picoeukaryote Fe stress genes were strikingly abundant in SCML metatranscriptomes. Using a biogeochemical proxy with data from a 40-y time series, we find that diatoms growing in California Current SCMLs are persistently Fe deficient during the spring and summer growing season. We also find that the spatial extent of Fe deficiency within California Current SCMLs has significantly increased over the last 25 y in line with a regional climate index. Finally, we show that diatom Fe deficiency may be common in the subsurface of major upwelling zones worldwide. Our results have important implications for our understanding of the biogeochemical consequences of marine SCML formation and maintenance