Photochemical reactivity of ancient marine dissolved organic carbon

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 39 (2012): L18602, doi:10.1029/2012GL052974.Marine dissolved organic carbon (DOC) is the largest reservoir of reduced carbon in seawater and persists up to 4,000–6,000 conventional radiocarbon (14C) years on average. Photochemical degradation has been suggested as a geochemical sink for these long-lived molecules, yet there have been no studies relating photochemical lability to the 14C-ages of surface DOC. We observed apparent second order (2°) kinetics with respect to DOC and a strong trend from Δ14C-enriched to depleted values during exhaustive photomineralization of surface marine DOC with high energy UV light. Geochemically, these results suggest that surface DOC is an isotopically-heterogeneous mixture of molecules for which photochemical lability and 14C ages are correlated. Photochemical mineralization may therefore be an important control on the persistence of 14C-depleted DOC in the ocean.This study was supported under NSF grant OCE-0961980 to E. R. M. Druffel.2013-03-2

Beyond Purity: Moral Disgust toward Bad Character

Previous studies support a link between moral disgust and impurity, while anger is linked to harm. We challenge this strict correspondence, and show that disgust is sensitive to information about moral character, even for harm violations. By contrast, anger is sensitive to information about actions, including their moral wrongness and consequences. Study 1 examined disgust and anger toward an action that indicates especially bad moral character (animal cruelty) versus an action that is more wrong (domestic abuse). Animal cruelty was associated with more disgust, whereas domestic abuse was associated with more anger. Studies 2 and 3 manipulated character by varying the agent’s desire to cause harm, and also varied the action’s harmful consequences. Desire to harm predicted only disgust (controlling for anger), while consequences were more closely related to anger (controlling for disgust). Taken together, these results indicate disgust responds to evidence of bad moral character, not just to impurity

Optimizing a microwave gas ion source for continuous-flow accelerator mass spectrometry

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of American Institute of Physics for personal use, not for redistribution. The definitive version was published in Review of Scientific Instruments 83 (2012): 02B304, doi:10.1063/1.3656408.A 2.45 GHz microwave ion source coupled with a magnesium charge exchange canal (CxC) has been successfully adapted to a large acceptance radiocarbon accelerator mass spectrometry system at the National Ocean Sciences AMS Facility (NOSAMS), Woods Hole Oceanographic Institution. CO2 samples from various preparation sources are injected into the source through a glass capillary at 370 µl/min. Routine system parameters are about 120 - 140 µA of negative 12C current after the CxC, leading to about 400 14C counts per second for a modern sample and implying a system efficiency of 0.2%. While these parameters already allow us to perform high quality AMS analyses on large samples, we are working on ways to improve the output of the ion source regarding emittance and efficiency. Modeling calculations suggest modifications in the extraction triode geometry, shape and size of the plasma chamber could improve emittance and hence ion transport efficiency. Results of experimental tests of these modifications are presented.This work has been supported by the US National Science Foundation through Cooperative Agreement OCE-0753487

Comprehensive Solid-State Characterization of Rare Earth Flouride Nanoparticles

The combination of multinuclear solid-state NMR spectroscopy and powder X-ray diffraction has been applied to characterize the octahedron-shaped crystalline nanoparticle products resulting from an inverse micelle synthesis. Rietveld refinements of the powder X-ray diffraction data from the nanoparticles revealed their general formula to be (H3O)Y3F10·xH2O. 1H magic-angle spinning (MAS) NMR experiments provided information on sample purity and served as an excellent probe of the zeolithic incorporation of atmospheric water. 19F MAS NMR experiments on a series of monodisperse nanoparticle samples of various sizes yielded spectra featuring three unique 19F resonances arising from three different fluorine sites within the (H3O)Y3F10·xH2O crystal structure. Partial removal of zeolithic water from the internal cavities and tunnels of the nanoparticles led to changes in the integrated peak intensities in the 19F MAS NMR spectra; the origin of this behavior is discussed in terms of 19F longitudinal relaxation. 19F–89Y variable-amplitude cross-polarization (VACP) NMR experiments on both stationary samples and samples under MAS conditions indicated that two distinct yttrium environments are present, and on the basis of the relative peak intensities, the population of one of the two sites is closely linked to the nanoparticle size. Both 19F MAS and 19F–89Y VACP/MAS experiments indicated small amounts of an impurity present in certain nanoparticles; these are postulated to be spherical amorphous YF3 nanoparticles. We discuss the importance of probing molecular-level structure in addition to microscopic structure and how the combination of these characterization methods is crucial for understanding nanoparticle design, synthesis, and application

Recognizing Emotions in a Foreign Language

Expressions of basic emotions (joy, sadness, anger, fear, disgust) can be recognized pan-culturally from the face and it is assumed that these emotions can be recognized from a speaker's voice, regardless of an individual's culture or linguistic ability. Here, we compared how monolingual speakers of Argentine Spanish recognize basic emotions from pseudo-utterances ("nonsense speech") produced in their native language and in three foreign languages (English, German, Arabic). Results indicated that vocal expressions of basic emotions could be decoded in each language condition at accuracy levels exceeding chance, although Spanish listeners performed significantly better overall in their native language ("in-group advantage"). Our findings argue that the ability to understand vocally-expressed emotions in speech is partly independent of linguistic ability and involves universal principles, although this ability is also shaped by linguistic and cultural variables

Childhood trauma may increase risk of psychosis and mood disorder in genetically high-risk children and adolescents by enhancing the accumulation of risk indicators

Background: Genetically high-risk children carry indicators of brain dysfunctions that adult patients with schizophrenia or bipolar disorder display. The accumulation of risk indicators would have a higher predictive value of a later transition to psychosis or mood disorder than each individual risk indicator. Since more than 50% of adult patients report having been exposed to childhood trauma, we investigated whether exposure to trauma during childhood was associated with the early accumulation of risk indicators in youths at genetic risk. Methods: We first inspected the characteristics of childhood trauma in 200 young offspring (51% male) born to a parent affected by DSM-IV schizophrenia, bipolar disorder, or major depressive disorder. A subsample of 109 offspring (51% male) had measurements on four risk indicators: cognitive impairments, psychotic-like experiences, nonpsychotic nonmood childhood DSM diagnoses, poor global functioning. Trauma was assessed from direct interviews and reviews of lifetime medical and school records of offspring. Results: Trauma was present in 86 of the 200 offspring (43%). The relative risk of accumulating risk indicators in offspring exposed to trauma was 3.33 (95% CI 1.50, 7.36), but more pronounced in males (RR = 4.64, 95% CI 1.71, 12.6) than females (RR = 2.01, 95% CI 0.54, 7.58). Conclusion: Childhood trauma would be related to the accumulation of developmental precursors of major psychiatric disorders and more so in young boys at high genetic risk. Our findings may provide leads for interventions targeting the early mechanisms underlying the established relation between childhood trauma and adult psychiatric disorders

The influence of microstructure on charge separation dynamics in organic bulk heterojunction materials for solar cell applications

Light-induced charge formation is essential for the generation of photocurrent in organic solar cells. In order to gain a better understanding of this complex process, we have investigated the femtosecond dynamics of charge separation upon selective excitation of either the fullerene or the polymer in different bulk heterojunction blends with well-characterized microstructure. Blends of the pBTTT and PBDTTPD polymers with PCBM gave us access to three different scenarios: either a single intermixed phase, an intermixed phase with additional pure PCBM clusters, or a three-phase microstructure of pure polymer aggregates, pure fullerene clusters and intermixed regions. We found that ultrafast charge separation (by electron or hole transfer) occurs predominantly in intermixed regions, while charges are generated more slowly from excitons in pure domains that require diffusion to a charge generation site. The pure domains are helpful to prevent geminate charge recombination, but they must be sufficiently small not to become exciton traps. By varying the polymer packing, backbone planarity and chain length, we have shown that exciton diffusion out of small polymer aggregates in the highly efficient PBDTTPD:PCBM blend occurs within the same chain and is helped by delocalization