Cone pigment variations in four genera of new world monkeys

AbstractPrevious research revealed significant individual variations in opsin genes and cone photopigments in several species of platyrrhine (New World) monkeys and showed that these in turn can yield significant variations in color vision. To extend the understanding of the nature of color vision in New World monkeys, electroretinogram flicker photometry was used to obtain spectral sensitivity measurements from representatives of four platyrrhine genera (Cebus, Leontopithecus, Saguinus, Pithecia). Animals from each genus were found to be polymorphic for middle to long-wavelength (M/L) sensitive cones. The presence of a short-wavelength sensitive photopigment was established as well so these animals conform to the earlier pattern in predicting that all male monkeys are dichromats while, depending on their opsin gene array, individual females can be either dichromatic or trichromatic. Across subjects a total of five different M/L cone pigments were inferred with a subset of three of these present in each species

Beyond the Red Pen: Clarifying Our Role in the Response Process

Describes two research studies with high school teachers and students that examine various aspects of both students\u27 and teachers\u27 perspectives on teacher responses to student writing. Examines how well teachers put their own theory about writing instruction into practice with their response style; analyzes teacher comments and students\u27 understanding of them; and offers the teachers\u27 responses to the studies

Zigzag-shaped nickel nanowires via organometallic template-free route

In this manuscript, the formation of nickel nanowires (average size: several tens to hundreds of μm long and 1.0-1.5 μm wide) at low temperature is found to be driven by dewetting of liquid organometallic precursors during spin coating process and by self-assembly of Ni clusters. Elaboration of metallic thin films by low temperature deposition technique makes the preparation process compatible with most of the substrates. The use of iron and cobalt precursor shows that the process could be extended to other metallic systems. In this work, AFM and SEM are used to follow the assembly of Ni clusters into straight or zigzag lines. The formation of zigzag structure is specific to the Ni precursor at appropriate preparation parameters. This template free process allows a control of anisotropic structures with homogeneous sizes and angles on standard Si/SiO2 surface

Floating stones off El Hierro, Canary Islands: xenoliths of pre-island sedimentary origin in the early products of the October 2011 eruption

The eruption that started off the south coast of El Hierro, Canary Islands, in October 2011 has emitted intriguing eruption products found floating in the sea. These specimens appeared as floating volcanic "bombs" that have in the meantime been termed "restingolites" (after the close-by village of La Restinga) and exhibit cores of white and porous pumice-like material. Currently the nature and origin of these "floating stones" is vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i) juvenile high-silica magma (e.g. rhyolite), (ii) remelted magmatic material (trachyte), (iii) altered volcanic rock, or (iv) reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have collected and analysed the structure and composition of samples and compared the results to previous work on similar rocks found in the archipelago. Based on their high silica content, the lack of igneous trace element signatures, and the presence of remnant quartz crystals, jasper fragments and carbonate relicts, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary rocks that were picked up and heated by the ascending magma causing them to partially melt and vesiculate. They hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies in the Canary Islands as well as in similar Atlantic islands that rest on sediment/covered ocean crust (e.g. Cape Verdes, Azores). The occurrence of these "restingolites" does therefore not indicate the presence of an explosive high-silica magma that is involved in the ongoing eruption

CO2 bubble generation and migration during magma-carbonate interaction

We conducted quantitative textural analysis of vesicles in high temperature and pressure carbonate assimilation experiments (1200 °C, 0.5 GPa) to investigate CO2 generation and subsequent bubble migration from carbonate into magma. We employed Mt. Merapi (Indonesia) and Mt. Vesuvius (Italy) compositions as magmatic starting materials and present three experimental series using (1) a dry basaltic-andesite, (2) a hydrous basaltic-andesite (2 wt% H2O), and (3) a hydrous shoshonite (2 wt% H2O). The duration of the experiments was varied from 0 to 300 s, and carbonate assimilation produced a CO2-rich fluid and CaO-enriched melts in all cases. The rate of carbonate assimilation, however, changed as a function of melt viscosity, which affected the 2D vesicle number, vesicle volume, and vesicle size distribution within each experiment. Relatively low-viscosity melts (i.e. Vesuvius experiments) facilitated efficient removal of bubbles from the reaction site. This allowed carbonate assimilation to continue unhindered and large volumes of CO2 to beliberated, a scenario thought to fuel sustained CO2-driven eruptions at the surface. Conversely, at higher viscosity (i.e. Merapi experiments), bubble migration became progressively inhibited and bubble concentration at the reaction site caused localised volatile over-pressure that can eventually trigger short-lived explosive outbursts. Melt viscosity therefore exerts a fundamental control on carbonate assimilation rates and, by consequence, the style of CO2-fuelled eruptions

CO2 bubble generation and migration during magma–carbonate interaction

We conducted quantitative textural analysis of vesicles in high temperature and pressure carbonate assimilation experiments (1200 °C, 0.5 GPa) to investigate CO2 generation and subsequent bubble migration from carbonate into magma. We employed Mt. Merapi (Indonesia) and Mt. Vesuvius (Italy) compositions as magmatic starting materials and present three experimental series using (1) a dry basaltic-andesite, (2) a hydrous basaltic-andesite (2 wt% H2O), and (3) a hydrous shoshonite (2 wt% H2O). The duration of the experiments was varied from 0 to 300 s, and carbonate assimilation produced a CO2-rich fluid and CaO-enriched melts in all cases. The rate of carbonate assimilation, however, changed as a function of melt viscosity, which affected the 2D vesicle number, vesicle volume, and vesicle size distribution within each experiment. Relatively low-viscosity melts (i.e. Vesuvius experiments) facilitated efficient removal of bubbles from the reaction site. This allowed carbonate assimilation to continue unhindered and large volumes of CO2 to be liberated, a scenario thought to fuel sustained CO2-driven eruptions at the surface. Conversely, at higher viscosity (i.e. Merapi experiments), bubble migration became progressively inhibited and bubble concentration at the reaction site caused localised volatile over-pressure that can eventually trigger short-lived explosive outbursts. Melt viscosity therefore exerts a fundamental control on carbonate assimilation rates and, by consequence, the style of CO2-fuelled eruptions

Environmental disclosure in Spain: Corporate characteristics and media exposure

Social and environmental issues have become a major concern for accounting research over the past two decades. Social and Environmental Accounting has attracted the attention of a number of researchers attempting to understand, explain and predict the disclosure of information on the social and environmental implications of business activities. Empirical research has hypothesized that size, profitability and the potential environmental impact of the firm are the main factors explaining the amount of information disclosed. On the other hand, several studies have focused on the motivations for disclosing environmental information, hypothesizing that disclosures are aimed at building or sustaining corporate legitimacy. We test the main hypotheses developed to date by empirical research with regard to the disclosure of environmental information based on a sample of companies listed on the Madrid Stock Exchange. Results of a content analysis show that firms disclosing environmental information tend to be larger, have higher risk (measured by the beta coefficient) and operate in industries that have a high potential environmental impact. The environmental implications of the activities carried out by these companies also seem to receive more attention from print media. Our results also provide evidence that two factors directly associated with the amount of environmental information disclosed are the potential environmental impact of the industry and the extent of media coverage of the firms

Magma-Carbonate Interaction Processes and Associated CO2 Release at MerapiVolcano, Indonesia: Insights from Experimental Petrology

There is considerable evidence for continuing, late-stage interaction between the magmatic system at Merapi volcano, Indonesia, and local crustal carbonate (limestone). Calc-silicate xenoliths within Merapi basaltic-andesite eruptive rocks display textures indicative of intense interaction between magma and crustal carbonate, and Merapi feldspar phenocrysts frequently contain crustally contaminated cores and zones. To resolve the interaction processes between magma and limestone in detail we have performed a series of time-variable decarbonation experiments in silicate melt, at magmatic pressure and temperature, using a Merapi basaltic-andesite and local Javanese limestone as starting materials.We have used in situ analytical methods to determine the elemental and strontium isotope composition of the experimental products and to trace the textural, chemical, and isotopic evolution of carbonate assimilation. The major processes of magma^carbonate interaction identified are: (1) rapid decomposition and degassing of carbonate; (2) generation of a Ca-enriched, highly radiogenic strontium contaminant melt, distinct from the starting material composition; (3) intense CO2 vesiculation, particularly within the contaminated zones; (4) physical mingling between the contaminated and unaffected melt domains; (5) chemical mixing between melts. The experiments reproduce many of the features of magma^carbonate interaction observed in the natural Merapi xenoliths and feldspar phenocrysts. The Ca-rich, high 87Sr/86Sr contaminant melt produced in the experiments is considered as a precursor to the Ca-rich (often ‘hyper-calcic’) phases found in the xenoliths and the contaminated zones inMerapi feldspars.The xenoliths also exhibit micro-vesicular textures that can be linked to the CO2 liberation process seen in the experiments.This study, therefore, provides well-constrained petrological insights into the problem of crustal interaction at Merapi and points toward the substantial impact of such interaction on the volatile budget of the volcano

Investigating H2O contents in clinopyroxene from explosive versus effusive eruption products from Merapi volcano, Indonesia

&amp;lt;p&amp;gt;The 2010 eruption of Merapi produced pyroclastic deposits and lava flows that are compositionally very similar, raising the question as to the underlying reason of the differences in eruptive styles between the various phases of the 2010 eruptive events. To test whether primary magmatic volatile content is the reason for the different eruption styles, we analyzed magmatic water contents in nominally anhydrous clinopyroxene crystals contained in lava and ash from the 2010 eruptive events. We utilized two analytical approaches: (i) Fourier-transform infrared spectroscopy (FTIR) analysis of fresh clinopyroxene from the ash and lava samples and (ii) FTIR analysis of clinopyroxene both prior to and after experimental re-hydration. By employing calculated partition coefficients, we determined the magmatic water content of the magma from which the various crystals grew. The magmatic water content determined from the unmodified clinopyroxenes from lava samples yield a range of 0.35 wt.% to 2.02 wt.% H&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O, whereas magmatic water contents determined from untreated clinopyroxene contained in the ash samples range between 0.04 and 3.25 wt.%, with two outliers at 4.62 and 5.19 and wt.%, respectively. In contrast, for the rehydrated crystals the range for lava derived clinopyroxene crystals is between 1.94 and 2.19 wt.% and for ash between 1.74 and 2.66 wt.%, with two crystals at extreme values of 0.85 and 3.20 wt.%. We interpret these results to indicate that crystals from different populations are present in the 2010 eruptive products, with the dominant group reflecting relatively low magmatic H&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O contents (around 2 wt.%) due to storage in shallow magma reservoirs and pockets at high levels within the Merapi plumbing systems (e.g. top 3 km). The overall higher H&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O range and the occasionally more extreme values recorded in clinopyroxenes from ash deposits may then represent the presence of a crystal population that last equilibrated at deeper levels and at higher water contents, i.e. these crystals derive from the replenishing magma that activated the shallow portion of the plumbing system during the 2010 events. While this is work in progress, our results so far seem to suggest that the pyroclastic deposits of the 2010 Merapi eruption may contain a higher fraction of clinopyroxene derived from &amp;amp;#8216;deeper magma&amp;amp;#8217; with higher H&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O contents then what we have detected in associated lavas.&amp;lt;/p&amp;gt; </jats:p