Infrared and Near-Infrared Spectroscopy of Acetylacetone and Hexafluoroacetylacetone

The infrared and near-infrared spectra of acetylacetone, acetylacetone-d8, and hexafluoroacetylacetone are characterized from experiment and computations at different levels. In the fundamental region, the intramolecular hydrogen bonded OH-stretching transition is clearly observed as a very broad band with substantial structure and located at significantly lower frequency compared to common OH-stretching frequencies. There is no clear evidence for OH-stretching overtone transitions in the near-infrared region, which is dominated by the CH-stretching overtones of the methine and methyl CH bonds. From molecular dynamics (MD) simulations, with a potential energy surface previously validated for tunneling splittings, the infrared spectra are determined and used in assigning the experimentally measured ones. It is found that the simulated spectrum in the region associated with the proton transfer mode is exquisitely sensitive to the height of the barrier for proton transfer. Comparison of the experimental and the MD simulated spectra establishes that the barrier height is around 2.5 kcal/mol, which favorably compares with 3.2 kcal/mol obtained from high-level electronic structure calculations

Mammals of Iowa: Holocene to the End of the 20th Century

This review of Iowa\u27s mammal fauna at the close of the 20th century summarizes changes in distributional patterns following Euroamerican settlement in the early 1800s. Data from historical records, museum specimens, and presettlement late Holocene fossils indicate presence of 69 resident mammals at that time. Hunting pressures and the conversion of prairie and forest to agricultural fields reduced the populations and ranges of many state mammals, and 14 species were extirpated by 1900. An additional 15 species are either uncommon or rare today, and the Iowa Department of Natural Resources lists four species as endangered, three as threatened and one as of special concern. Species dependent upon either forest or prairie have suffered most; forest-edge species generally have thrived and even increased. River otters and a captive bison herd were reintroduced recently, and several (like the spotted skunk and the bobcat) have benefited from setaside acreage, flood-plain and wetland reclamation, and roadside management initiatives. Species distribution and relative abundance vary slightly among the state\u27s five geographic regions

The topobiology of chemical elements in seabird feathers

The highly organized morphogenesis of bird feathers holds important phylo- and ontogenetic information on the evolution of birds, organogenesis, tissue regeneration, and the health status of individual animals. Altered topobiological patterns are regularly used as retrospective evidence for disturbed developmental trajectories due to the past exposure to environmental stressors. Using the most advanced high-resolution (5-70 μm) X-ray fluorescence microscopy (XFM), we describe in the feathers from three species of Procellariiformes hitherto unknown, depositions of elements (Zn, Ca, Br, Cu, Fe) that are independent of pigmentation or any underlying variation in density or polymer structure. In the case of Zn, the pattern across several species of Procellariiformes, but not other species, consisted of highly regular bands of Zn numbering 30-32, which may reflect the estimated number of days of active feather growth or the duration of the moult period. Thus, speculatively, the highly consistent Zn pattern might be the result of a so far unknown diurnal systemic regulation rather than local heterogeneity amongst the follicular stem cells

Novel application of X-ray fluorescence microscopy (XFM) for the non-destructive micro-elemental analysis of natural mineral pigments on Aboriginal Australian objects

Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.This manuscript presents the first non-destructive synchrotron micro-X-ray fluorescence study of natural mineral pigments on Aboriginal Australian objects. Our results demonstrate the advantage of XFM (X-ray fluorescence microscopy) of Aboriginal Australian objects for optimum sensitivity, elemental analysis, micron-resolution mapping of pigment areas and the method also has the advantage of being non-destructive to the cultural heritage objects. Estimates of pigment thickness can be calculated. In addition, based on the elemental maps of the pigments, further conclusions can be drawn on the composition and mixtures and uses of natural mineral pigments and whether the objects were made using traditional or modern methods and materials. This manuscript highlights the results of this first application of XFM to investigate complex mineral pigments used on Aboriginal Australian objects

Palaeomagnetic and synchrotron analysis of \u3e1.95 Ma fossil-bearing palaeokarst at Haasgat, South Africa

Palaeomagnetic analysis indicates that Haasgat, a fossil-bearing palaeocave in the Gauteng Province of South Africa, is dominated by reversed magnetic polarity in its oldest, deepest layers and normal polarity in the younger layers. The presence of in-situ Equus specimens suggests an age of less than ~2.3 Ma, while morphological analysis of faunal specimens from the ex-situ assemblage suggests an age greater than 1.8 Ma. Given this faunal age constraint, the older reversed polarity sections most likely date to the beginning of the Matuyama Chron (2.58–1.95 Ma), while the younger normal polarity deposits likely date to the very beginning of the Olduvai Sub-Chron (1.95–1.78 Ma). The occurrence of a magnetic reversal from reversed to normal polarity recorded in the sequence indicates the deposits of the Bridge Section date to ~1.95 Ma. All the in-situ fossil deposits that have been noted are older than the 1.95 Ma reversal, but younger than 2.3 Ma. Haasgat therefore dates to an interesting time period in South African human evolution that saw the last occurrence of two australopith species at ~2.05–2.02 Ma (Sts5 Australopithecus africanus from Sterkfontein Member 4) to ~1.98 Ma ( Australopithecus sediba from Malapa) and the first occurrence of early Homo (Sk847), Paranthropus and the Oldowan within Swartkrans Member 1 between ~2.0 Ma and ~1.8 Ma

Distribution of Metals in the Termite Tumulitermes tumuli (Froggatt): Two Types of Malpighian Tubule Concretion Host Zn and Ca Mutually Exclusively

The aim of this study was to determine specific distribution of metals in the termite Tumulitermes tumuli (Froggatt) and identify specific organs within the termite that host elevated metals and therefore play an important role in the regulation and transfer of these back into the environment. Like other insects, termites bio-accumulate essential metals to reinforce cuticular structures and utilize storage detoxification for other metals including Ca, P, Mg and K. Previously, Mn and Zn have been found concentrated in mandible tips and are associated with increased hardness whereas Ca, P, Mg and K are accumulated in Malpighian tubules. Using high resolution Particle Induced X-Ray Emission (PIXE) mapping of whole termites and Scanning Electron Microscope (SEM) Energy Dispersive X-ray (EDX) spot analysis, localised accumulations of metals in the termite T. tumuli were identified. Tumulitermes tumuli was found to have proportionally high Mn concentrations in mandible tips. Malpighian tubules had significant enrichment of Zn (1.6%), Mg (4.9%), P (6.8%), Ca (2.7%) and K (2.4%). Synchrotron scanning X-ray Fluorescence Microprobe (XFM) mapping demonstrated two different concretion types defined by the mutually exclusive presence of Ca and Zn. In-situ SEM EDX realisation of these concretions is problematic due to the excitation volume caused by operating conditions required to detect minor amounts of Zn in the presence of significant amounts of Na. For this reason, previous researchers have not demonstrated this surprising finding

Caenorhabditis elegans Maintains Highly Compartmentalized Cellular Distribution of Metals and Steep Concentration Gradients of Manganese

Bioinorganic chemistry is critical to cellular function. Homeostasis of manganese (Mn), for example, is essential for life. A lack of methods for direct in situ visualization of Mn and other biological metals within intact multicellular eukaryotes limits our understanding of management of these metals. We provide the first quantitative subcellular visualization of endogenous Mn concentrations (spanning two orders of magnitude) associated with individual cells of the nematode, Caenorhabditis elegans

The Milky Way Tomography With SDSS. III. Stellar Kinematics

We study Milky Way kinematics using a sample of 18.8 million main-sequence stars with r 20 degrees). We find that in the region defined by 1 kpc < Z < 5 kpc and 3 kpc < R < 13 kpc, the rotational velocity for disk stars smoothly decreases, and all three components of the velocity dispersion increase, with distance from the Galactic plane. In contrast, the velocity ellipsoid for halo stars is aligned with a spherical coordinate system and appears to be spatially invariant within the probed volume. The velocity distribution of nearby (Z < 1 kpc) K/M stars is complex, and cannot be described by a standard Schwarzschild ellipsoid. For stars in a distance-limited subsample of stars (< 100 pc), we detect a multi-modal velocity distribution consistent with that seen by HIPPARCOS. This strong non-Gaussianity significantly affects the measurements of the velocity-ellipsoid tilt and vertex deviation when using the Schwarzschild approximation. We develop and test a simple descriptive model for the overall kinematic behavior that captures these features over most of the probed volume, and can be used to search for substructure in kinematic and metallicity space. We use this model to predict further improvements in kinematic mapping of the Galaxy expected from Gaia and the Large Synoptic Survey Telescope.NSF AST-615991, AST-0707901, AST-0551161, AST-02-38683, AST-06-07634, AST-0807444, PHY05-51164NASA NAG5-13057, NAG5-13147, NNXO-8AH83GPhysics Frontier Center/Joint Institute for Nuclear Astrophysics (JINA) PHY 08-22648U.S. National Science FoundationMarie Curie Research Training Network ELSA (European Leadership in Space Astrometry) MRTN-CT-2006-033481Fermi Research Alliance, LLC, United States Department of Energy DE-AC02-07CH11359Alfred P. Sloan FoundationParticipating InstitutionsJapanese MonbukagakushoMax Planck SocietyHigher Education Funding Council for EnglandMcDonald Observator

The Milky Way Tomography with SDSS: III. Stellar Kinematics

We study Milky Way kinematics using a sample of 18.8 million main-sequence stars with r<20 and proper-motion measurements derived from SDSS and POSS astrometry, including ~170,000 stars with radial-velocity measurements from the SDSS spectroscopic survey. Distances to stars are determined using a photometric parallax relation, covering a distance range from ~100 pc to 10 kpc over a quarter of the sky at high Galactic latitudes (|b|>20 degrees). We find that in the region defined by 1 kpc <Z< 5 kpc and 3 kpc <R< 13 kpc, the rotational velocity for disk stars smoothly decreases, and all three components of the velocity dispersion increase, with distance from the Galactic plane. In contrast, the velocity ellipsoid for halo stars is aligned with a spherical coordinate system and appears to be spatially invariant within the probed volume. The velocity distribution of nearby ($Z<1$ kpc) K/M stars is complex, and cannot be described by a standard Schwarzschild ellipsoid. For stars in a distance-limited subsample of stars (<100 pc), we detect a multimodal velocity distribution consistent with that seen by HIPPARCOS. This strong non-Gaussianity significantly affects the measurements of the velocity ellipsoid tilt and vertex deviation when using the Schwarzschild approximation. We develop and test a simple descriptive model for the overall kinematic behavior that captures these features over most of the probed volume, and can be used to search for substructure in kinematic and metallicity space. We use this model to predict further improvements in kinematic mapping of the Galaxy expected from Gaia and LSST.Comment: 90 pages, 26 figures, submitted to Ap

Detection of Genetically Altered Copper Levels in Drosophila Tissues by Synchrotron X-Ray Fluorescence Microscopy

Tissue-specific manipulation of known copper transport genes in Drosophila tissues results in phenotypes that are presumably due to an alteration in copper levels in the targeted cells. However direct confirmation of this has to date been technically challenging. Measures of cellular copper content such as expression levels of copper-responsive genes or cuproenzyme activity levels, while useful, are indirect. First-generation copper-sensitive fluorophores show promise but currently lack the sensitivity required to detect subtle changes in copper levels. Moreover such techniques do not provide information regarding other relevant biometals such as zinc or iron. Traditional techniques for measuring elemental composition such as inductively coupled plasma mass spectroscopy are not sensitive enough for use with the small tissue amounts available in Drosophila research. Here we present synchrotron x-ray fluorescence microscopy analysis of two different Drosophila tissues, the larval wing imaginal disc, and sectioned adult fly heads and show that this technique can be used to detect changes in tissue copper levels caused by targeted manipulation of known copper homeostasis genes