“Sweating meteorites”-Water-soluble salts and temperature variation in ordinary chondrites and soil from the hot desert of Oman

The common appearance of hygroscopic brine (“sweating”) on ordinary chondrites (OCs) from Oman during storage under room conditions initiated a study on the role of water-soluble salts on the weathering of OCs. Analyses of leachates from OCs and soils, combined with petrography of alteration features and a 11-month record of in situ meteorite and soil temperatures, are used to evaluate the role of salts in OC weathering. Main soluble ions in soils are Ca2+, SO42−, HCO3−, Na+, and Cl−, while OC leachates are dominated by Mg2+ (from meteoritic olivine), Ca2+ (from soil), Cl− (from soil), SO42− (from meteoritic troilite and soil), and iron (meteoritic). “Sweating meteorites” mainly contain Mg2+ and Cl−. The median Na/Cl mass ratio of leachates changes from 0.65 in soils to 0.07 in meteorites, indicating the precipitation of a Na-rich phase or loss of an efflorescent Na-salt. The total concentrations of water-soluble ions in bulk OCs ranges from 600 to 9000 μg g−1 (median 2500 μg g−1) as compared to 187–14140 μg g−1 in soils (median 1148 μg g−1). Soil salts dissolved by rain water are soaked up by meteorites by capillary forces. Daily heating (up to 66.3 °C) and cooling of the meteorites cause a pumping effect, resulting in a strong concentration of soluble ions in meteorites over time. The concentrations of water-soluble ions in meteorites, which are complex mixtures of ions from the soil and from oxidation and hydrolysis of meteoritic material, depend on the degree of weathering and are highest at W3. Input of soil contaminants generally dominates over the ions mobilized from meteorites. Silicate hydrolysis preferentially affects olivine and is enhanced by sulfide oxidation, producing local acidic conditions as evidenced by jarosite. Plagioclase weathering is negligible. After completion of troilite oxidation, the rate of chemical weathering slows down with continuing Ca-sulfate contamination.

Age of the Peach Springs Tuff, Southeastern California and Western Arizona

Sanidine separates from pumice of the early Miocene Peach Springs Tuff are concordantly dated at 18.5 ± 0.2 Ma by two isotopic techniques. The Peach Springs Tuff is the only known unit that can be correlated between isolated outcrops of Miocene strata from the central Mojave Desert of southeastern California to the western Colorado Plateau in Arizona, across five structural provinces, a distance of 350 km. Thus the age of the Peach Springs Tuff is important to structural and paleogeographic reconstructions of a large region. Biotite and sanidine separates from bulk samples of the Peach Springs Tuff from zones of welding and vapor-phase alteration have not produced consistent ages by the K-Ar method. Published ages of mineral separates from 17 localities ranged from 16.2 to 20.5 Ma. Discordant 40Ar/39Ar incremental release spectra were obtained for one biotite and two of the sanidine separates. Ages that correspond to the last gas increments are as old as 27 Ma. The 40Ar/39Ar incremental release determinations on sanidine separated from blocks of Peach Springs Tuff pumice yield ages of 18.3 ± 0.3 and 18.6 ± 0.4 Ma. Laser fusion measurements yield a mean age of 18.51 ± 0.10. The results suggest that sanidine and biotite K-Ar ages older than about 18.5 Ma are due to inherited Ar from pre-Tertiary contaminants, which likely were incorporated into the tuff during deposition. Sanidine K-Ar ages younger than 18 Ma probably indicate incomplete extraction of radiogenic 40Ar, whereas laser fusion dates of biotite and hornblende younger than 18 Ma likely are due to postdepositional alteration. Laser fusion ages as high as 19.01 Ma on biotite grains from pumice suggest that minerals from pre-Tertiary country rocks also were incorporated in the magma chamber.

Atmospheric Dynamics of Hot Exoplanets

The characterization of exoplanetary atmospheres has come of age in the last decade, as astronomical techniques now allow for albedos, chemical abundances, temperature profiles and maps, rotation periods and even wind speeds to be measured. Atmospheric dynamics sets the background state of density, temperature and velocity that determines or influences the spectral and temporal appearance of an exoplanetary atmosphere. Hot exoplanets are most amenable to these characterization techniques; in the present review, we focus on highly-irradiated, large exoplanets (the "hot Jupiters"), as astronomical data begin to confront theoretical questions. We summarize the basic atmospheric quantities inferred from the astronomical observations. We review the state of the art by addressing a series of current questions and look towards the future by considering a separate set of exploratory questions. Attaining the next level of understanding will require a concerted effort of constructing multi-faceted, multi-wavelength datasets for benchmark objects. Understanding clouds presents a formidable obstacle, as they introduce degeneracies into the interpretation of spectra, yet their properties and existence are directly influenced by atmospheric dynamics. Confronting general circulation models with these multi-faceted, multi-wavelength datasets will help us understand these and other degeneracies. The coming decade will witness a decisive confrontation of theory and simulation by the next generation of astronomical data.

THE EFFECTS OF IRRADIATION ON HOT JOVIAN ATMOSPHERES: HEAT REDISTRIBUTION AND ENERGY DISSIPATION

Hot Jupiters, due to the proximity to their parent stars, are subjected to a strong irradiating flux that governs their radiative and dynamical properties. We compute a suite of three-dimensional circulation models with dual-band radiative transfer, exploring a relevant range of irradiation temperatures, both with and without temperature inversions. We find that, for irradiation temperatures T irr lsim 2000 K, heat redistribution is very efficient, producing comparable dayside and nightside fluxes. For T irr ≈ 2200-2400 K, the redistribution starts to break down, resulting in a high day-night flux contrast. Our simulations indicate that the efficiency of redistribution is primarily governed by the ratio of advective to radiative timescales. Models with temperature inversions display a higher day-night contrast due to the deposition of starlight at higher altitudes, but we find this opacity-driven effect to be secondary compared to the effects of irradiation. The hotspot offset from the substellar point is large when insolation is weak and redistribution is efficient, and decreases as redistribution breaks down. The atmospheric flow can be potentially subjected to the Kelvin-Helmholtz instability (as indicated by the Richardson number) only in the uppermost layers, with a depth that penetrates down to pressures of a few millibars at most. Shocks penetrate deeper, down to several bars in the hottest model. Ohmic dissipation generally occurs down to deeper levels than shock dissipation (to tens of bars), but the penetration depth varies with the atmospheric opacity. The total dissipated Ohmic power increases steeply with the strength of the irradiating flux and the dissipation depth recedes into the atmosphere, favoring radius inflation in the most irradiated objects. A survey of the existing data, as well as the inferences made from them, reveals that our results are broadly consistent with the observational trends.

Service Brand Relationship Quality: Hot or Cold?

Customers’ long-term brand relations are crucial drivers of a service brand’s sustainable competitive advantage. This research empirically examines the quality of customer-service brand relationships in the context of an airline’s frequent flyer program. The authors show that service brand relationship quality (BRQ) involves both a hot (based on emotions) and a cold (based on objectrelevant beliefs) component. They find that these two components have different implications for a service brand’s performance and are at least partially driven by different antecedents whose relative importance changes over time. Specifically, cold BRQ is important for word-of-mouth behavior and is strongly driven by partner quality (i.e., the generalized assessment of the brand in its role as a relationship counterpart). Hot BRQ, on the other hand, has a stronger impact on willingness to pay a price premium and consideration set size. In early stages of a customer-brand relationship hot BRQ is more strongly driven by self-congruence (i.e., consumer’s perception of the fit between his/her self and the brand’s personality), in later stages partner quality becomes more relevant. The authors discuss the implications of their findings for the development of BRQ and the implementation of alternative growth strategies in a services context.

Sulfate and Nitrate Assimilation in Leaves of Quercus ilex and Quercus pubescens Grown Near Natural CO2 Springs in Central Italy

The effect of long-term exposure to elevated pCO2 concentrations on sulfate and nitrate assimilation was studied under field conditions using leaves from Quercus ilex and Quercus pubescens trees growing with ambient or elevated CO2 concentrations in the vicinity of three natural CO2 springs, Bossoleto, Laiatico and Sulfatara, in Tuscany, Italy. The activity of the key enzymes of sulfate assimilation, adenosine 5′-phosphosulfate reductase (APR) and nitrate assimilation, nitrate reductase (NR), were measured together with the levels of acid soluble thiols, and soluble non-proteinogenic nitrogen compounds. Whereas NR activity remained unaffected in Q. ilex or increased Q. pubescence, APR activity decreased in the area of CO2 springs. The latter changes were often accompanied by increased GSH concentrations, apparently synthesized from H2S and SO2 present in the gas mixture emitted from the CO2 springs. Thus, the diminished APR activity in leaves of Q. ilex and Q. pubescence from spring areas can best be explained by the exposure to gaseous sulfur compounds. Although the concentrations of H2S and SO2 in the gas mixture emitted from the vents at the CO2 springs were low at the Bossoleto and Laiatico spring, these sulfur gases pose physiological effects, which may override consequences of elevated pCO2.

Identification of a new genomic hot spot of evolutionary diversification of protein function.

Establishment of phylogenetic relationships remains a challenging task because it is based on computational analysis of genomic hot spots that display species-specific sequence variations. Here, we identify a species-specific thymine-to-guanine sequence variation in the Glrb gene which gives rise to species-specific splice donor sites in the Glrb genes of mouse and bushbaby. The resulting splice insert in the receptor for the inhibitory neurotransmitter glycine (GlyR) conveys synaptic receptor clustering and specific association with a particular synaptic plasticity-related splice variant of the postsynaptic scaffold protein gephyrin. This study identifies a new genomic hot spot which contributes to phylogenetic diversification of protein function and advances our understanding of phylogenetic relationships.

Attributing trends in extremely hot days to changes in atmospheric dynamics

This paper presents a method for attributing regional trends in the frequency of extremely hot days (EHDs) to changes in the frequency of the atmospheric patterns that characterize such extraordinary events. The study is applied to mainland Spain and the Balearic Islands for the extended summers of the period 1958–2008, where significant and positive trends in maximum temperature (Tx) have been reported during the second half of the past century. First, the study area was split into eight regions attending to their different temporal variability of the daily Tx series obtained from the Spain02 gridded data set using a clustering procedure. Second, the large-scale atmospheric situations causing EHDs are defined by circulation types (CTs). The obtainment of the CTs differs from the majority of CT classifications proposed in the literature. It is based on regional series and on a previous characterization of the main atmospheric situations obtained using only some days classified as extremes in the different regions. Three different atmospheric fields (SLP, T850, and Z500) from ECMWF reanalysis and analysis data and combinations of them (SLP–T850, SLP–Z500, and T850–Z500) are used to produce six different CT classifications. Subsequently, links between EHD occurrence in the different regions and CT for all days have been established. Finally, a simple model to relate the trends in EHDsfor each region to the changes in the CT frequency appearance has been formulated. Most regions present positive and significant trends in the occurrence of EHDs. The CT classifications using two variables perform better. In particular, SLP–T850 is the best for characterizing the atmospheric situations leading to EHD occurrences for most of the regions. Only a small number of CTs have significant trends in their frequency and are associated with high efficiency causing EHD occurrences in most regions simultaneously, especially in the northern and central regions. Attribution results show that changes in circulation can only explain some part of the regional EHD trends. The percentage of the trend attributable to changes in atmospheric dynamics varies from 15 to 50 %, depends on the region and is sensitive to the selected large-scale variables.

Di filosofye : ṿos zi iz un ṿi zi hot zikh entṿiḳelṭ

fun H̤ayim Zshiṭloṿsḳi

Life-long growth of Quercus ilex L. at natural CO2 springs acclimates sulphur, nitrogen and carbohydrate metabolism of the progeny to elevated pCO2

The aim of the present study was to analyse whether offspring of mature Quercus ilex trees grown under life-long elevated pCO2 show alterations in the physiological response to elevated pCO2 in comparison with those originating from mature trees grown at current ambient pCO2. To investigate changes in C- (for changes in photosynthesis, biomass and lignin see Polle, McKee & Blaschke Plant, Cell and Environment 24, 1075–1083, 2001), N-, and S-metabolism soluble sugar, soluble non-proteinogenic nitrogen compounds (TSNN), nitrate reductase (NR), thiols, adenosine 5′-phosphosulphate (APS) reductase, and anions were analysed. For this purpose Q. ilex seedlings were grown from acorns of mother tree stands at a natural spring site (elevated pCO2) and a control site (ambient pCO2) of the Laiatico spring, Central Italy. Short-term elevated pCO2 exposure of the offspring of control oaks lead to higher sugar contents in stem tissues, to a reduced TSNN content in leaves, and basipetal stem tissues, to diminished thiol contents in all tissues analysed, and to reduced APS reductase activity in both, leaves and roots. Most of the components of C-, N- and S-metabolism including APS reductase activity which were reduced due to short-term elevated pCO2 exposure were recovered by life-long growth under elevated pCO2 in the offspring of spring oaks. Still TSNN contents in phloem exudates increased, nitrate contents in lateral roots and glutathione in leaves and phloem exudates remained reduced in these plants. The present results demonstrated that metabolic adaptations of Q. ilex mother trees to elevated pCO2 can be passed to the next generation. Short- and long-term effects on source-to-sink relation and physiological and genetic acclimation to elevated pCO2 are discussed.

Was hot er gesogt? Oestraichsch sollen mer werden hot er gesogt? Waih geschriggen! Hoste gehört, was is gekummen vor a Geschrai in die Zeitungen? ...

Welsch (Projektbearbeiter): Kritische Kommentierung der Wahl Erzherzog Johanns zum Reichsverweser (29. Juni 1848): "Vier und draißig Ferschten un noch a Ferscht! ... Vier und draißig Geseires un noch a neue Geseire! Waih geschriggen!" Warnung vor der bevorstehenden Unterordnung Preußens: "Praißen is gewesen der Herr vun Taitschland, nanu soll es werden der Bedienter vun Oestreich."