Low ASI Research Articles

Could the association between ozone and arterial stiffness be modified by fish oil supplementation?

BackgroundArterial stiffness (AS) is an important predicting factor for cardiovascular disease. However, no epidemiological studies have ever explored the mediating role of biomarkers in the association between ozone and AS, nor weather fish oil modified such association. MethodsStudy participants were drawn from the UK biobank, and a total of 95,699 middle-aged and older adults were included in this study. Ozone was obtained from Community Multiscale Air Quality (CMAQ) model matched to residential addresses, fish oil from self-reported intake, and arterial stiffness was based on device measurements. First, we applied a double robust approach to explore the association between ozone or fish oil intake and arterial stiffness, adjusting for potential confounders at the individual and regional levels. Then, how triglycerides, apolipoprotein B (Apo B)/apolipoprotein A (ApoA) and non-high-density lipoprotein cholesterol (Non-HDL-C) mediate the relationship between ozone and AS. Last, the modifying role of fish oil was further explored by stratified analysis. ResultsThe mean age of participants was 55 years; annual average ozone exposure was associated with ASI (beta:0.189 [95%CI: 0.146 to 0.233], P < 0.001), and compared to participants who did not consume fish oil, fish oil users had a lower ASI (beta: 0.061 [95%CI: -0.111 to -0.010], P = 0.016). The relationship between ozone exposure and AS was mediated by triglycerides, ApoB/ApoA, and Non-HDL-C with mediation proportions ranging from 10.90% to 18.30%. Stratified analysis showed lower estimates on the ozone-AS relationship in fish oil users (P = 0.011). ConclusionOzone exposure was associated with higher levels of arterial stiffness, in contrast to fish oil consumption, which showed a protective association. The association between ozone exposure and arterial stiffness was partially mediated by some biomarkers. In the general population, fish oil consumption might provide protection against ozone-related AS.

Simulated drought stress unravels differential response and different mechanisms of drought tolerance in newly developed tropical field corn inbreds.

Corn is one of the most important cereal crops in the world with highest yield potential. Nevertheless, its potential productivity is constrained by the occurrences of drought stress worldwide. Besides, in the era of climate change, frequent occurrences of severe droughts are predicted. The present investigation was carried out at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad in split plot design to study response of twenty-eight new corn inbreds under drought free (well-watered) conditions and drought simulated by withholding irrigation from 40 to 75 DAS to create water stress. Significant differences among the corn inbreds, moisture treatments and interaction between inbreds were observed for morpho-physiological, yield and yield components indicating differential response of corn inbreds. The inbreds CAL 1426-2 (higher RWC, SLW& wax and lower ASI), PDM 4641(higher SLW, proline, & wax, and lower ASI) and GPM 114 (higher proline & wax, and lower ASI) were drought tolerant. These inbreds are having higher production potential (>5.0 t/ha) under moisture stress condition with less per cent reduction (<24.4%) over non-moisture stress condition and hence are putative candidates for developing drought tolerant hybrids suitable for rainfed ecosystem besides using them in population improvement program to combine different drought tolerant mechanisms to evolve highly potent drought tolerant inbreds. The results of the study suggested that proline content, wax content, anthesis silking interval, relative water content can be better surrogate traits to identify drought tolerant inbreds in corn.

Late Jurassic magmatism and associated Au–Cu polymetallic mineralization in the North China Craton: Constraints from U–Pb–Hf–Sr–Nd isotopes of the Xiayingfang intermediate-felsic igneous rocks

The Xiayingfang Au–Cu polymetallic deposit (22.5 Mt. @1.9 g/t Au, 0.54% Cu) in the northern margin of the North China Craton consists of the Xiajinbao and Dongliang ore blocks. It is characterized by multiple magmatic rocks, including rhyolitic tuff, granite porphyry, diorite porphyry, quartz porphyry, and monzonite porphyry. The Xiajinbao and Dongliang mineralization occurs mainly as auriferous quartz-sulfide veins in granite porphyry and diorite porphyry, respectively.Rhyolitic tuff, granite porphyry, diorite porphyry, quartz porphyry, and monzonite porphyry at Xiayingfang yielded zircon U–Pb ages of 162.3 ± 1.3 Ma (MSWD = 1.4), 161.8 ± 1.5 Ma (MSWD = 1.3), 162.7 ± 1.7 Ma (MSWD = 1.4), 162.9 ± 1.7 Ma (MSWD = 2.4), 162.7 ± 1.6 Ma (MSWD = 0.7), respectively, suggesting their Late Jurassic emplacement. The rhyolitic tuff, granite porphyry, quartz porphyry, and monzonite porphyry are characterized by high aluminum saturation index (ASI = 1.0 to 1.3), positive P2O5 vs. SiO2 correlation, negative Eu anomaly (δEu = 0.29 to 0.78), low average Nb/Th (3.05) and Nb/U (8.80) ratios, low Mg# values (14 to 42), negative zircon εHf(t) (–8.7 to –10.1) and high initial 87Sr/86Sr value (0.712 for granite porphyry), indicating a sedimentary origin. In contrast, the diorite porphyry is characterized by high Sr/Y (29.2 to 53.2), low Y (9.7 to 15.0 ppm) and Yb (1.4 to 1.8 ppm), indicating an adakite-like affinity. Moreover, its listric-shaped normalized REE patterns with no Eu anomalies, low ASI (0.8–0.9), zircon εHf(t) (–7.7 to –11.1), εNd(t) (–10 to –16) and initial 87Sr/86Sr (0.705 to 0.706), high Nb/Th (9.25), Nb/U (30.6) ratios, Mg# values (46 to 54), indicating a dominantly sub-continental lithospheric mantle (SCLM) source, which may have evolved to adakite-like signatures through amphibole fractionation. The mineral assemblages of paragenetic bornite, enargite and electrum at Xiayingfang reveals the highly oxidized condition of ore-related magma, as supported by the magnetic susceptibility (20 to 65 × 10–3SI unit) and average zircon Ce4+/Ce3+ ratio (352) of the diorite porphyry, and clearly different from those barren Xiayingfang porphyries (magnetic susceptibility below 1 × 10–3SI unit, and low average zircon Ce4+/Ce3+ ratio of 128). This reveals that the diorite porphyry may have been ore-causative at Xiayingfang, which is also supported by its clear ore-related alteration (illite, carbonate, and chlorite) and close spatial relations with the orebodies. Mineral Exploration programs in this area should therefore target the diorite porphyries instead.

Petrogenesis of Ordovician granitoids in Western Kunlun, NW Tibetan Plateau: Insights into the evolution of the Proto-Tethys Ocean

Abstract Granitoid rocks are universal in continental crust and are of special significance in understanding tectonic settings. This paper presents detailed zircon U-Pb dating, Hf isotope, whole-rock geochemistry, and Sr-Nd-Pb isotope analyses, and mineralogy of two Ordovician granitoid intrusions and one quartz diorite intrusion in Western Kunlun, NW Tibetan Plateau. The Yutian Complex is composed of diverse rock suites, including monzogabbros, quartz monzodiorites, monzogranites, and monzodioritic enclaves. These suites have similar rock formation ages (447–440 Ma) and minerals, e.g., amphibole grains from different suites belonging to pargasite. Moreover, they exhibit geochemical similarities, such as broadly parallel trace-element patterns characterized by enrichments in light rare earth elements and large ion lithophile elements, and depletions in high field strength elements, which are typical features of arc rocks. Furthermore, the studied samples display homogeneous zircon Hf values, e.g., εHf(t) = −1 to −3, and whole-rock isotopic compositions, e.g., εNd(t) = −4 to −6. Thus, they were most likely derived from a mantle wedge enriched by subducted sediments and fluids, which then evolved into different suites through fractional crystallization of hornblende and plagioclase. The ca. 440 Ma North Yutian quartz diorite intrusion, with an average of εHf(t) value of −6, was a product of the partial melting of mafic lower crust through slightly fractional crystallization of hornblende. In contrast, the ca. 470 Ma Aqiang granodiorite intrusion has εHf(t) values varying from −5 and −2, but it has heterogeneous petrological and geochemical features. It is considered to be a product of the partial melting of the overriding mantle wedge modified by fluids derived from the subducted Proto-Tethys slab and some mixed crustal materials. The Aqiang samples belong to the slightly fractionated I-type series, but they have variable alumina saturation index (ASI = molar Al2O3/[CaO – 3.33 × P2O5 + Na2O + K2O]) values (0.74–1.03) due to variable peraluminous biotite contents. The different suites in the Yutian Complex display low ASI values (&amp;lt;1) controlled by sources and fractional crystallization. The Yutian Complex and the North Yutian intrusion were emplaced during the southward subduction of the Proto-Tethys oceanic lithosphere, and the Aqiang intrusion was emplaced in response to the northward subduction.

Interplay Between Silicon Nanocrystal Size and Local Environment Within Porous Silicon on the Analyte-Dependent Photoluminescence Response.

Porous silicon (pSi) exhibits strong photoluminescence (PL) and its PL is often exploited for chemical sensor development. However, the sensor response is not uniform across a pSi specimen. We use co-localized confocal PL and Raman scattering mapping to establish a relationship between the analyte-induced PL response and the silicon nanocrystallite size, size distribution, and amorphous silicon (aSi) contribution across a pSi specimen. Using toluene as a model analyte, high analyte-induced PL response is associated with areas within the specimen that have (i) low aSi content, (ii) silicon nanocrystallites having diameters between 2 and 5 nm, and (iii) silicon nanocrystallites that exhibit a narrow size distributions (≤1% relative standard deviation).

Fluorine partitioning between titanite and silicate melt and its dependence on melt composition: experiments at 50–200 MPa and 875–925°C

We present experimental results constraining the partitioning of fluorine (F) between titanite and metaluminous silicate melt under H 2 O-saturated conditions at 50–200 MPa, 875–925 °C. Resulting experimental melts are metaluminous with ASI values [aluminium saturation index, calculated as molar Al 2 O 3 /(CaO+Na 2 O+K 2 O)] falling in the range 0.68–0.97. Titanite crystals and coexisting melts have F contents that vary from 0.2 to 2.6 wt% and from 0.2 to 3.2 wt%, respectively. The calculated proportion of the F–O substitution is within 0.02–0.28 per formula unit, which is predominantly compensated by the substitution of Al and Fe 3+ for Ti, as well as a subordinate amount of Ti–Mg 2+ substitution. The mass-ratio partition coefficient D Ttn − melt F is within 0.5–1.2, and there is little influence of pressure under the conditions investigated. However, the potential effect of temperature needs further investigation. D Ttn − melt F is positively correlated with melt ASI, and can be predicted using the following relation: D Ttn − melt F = 2.26 ∗ ASI – 1:05: This equation is valid only for metaluminous melts (ASI D Ttn − melt F is related to structural properties of F-bearing melts, which can incorporate higher F concentrations at lower ASI. Assuming that the high-Ti titanite investigated here is subject to ideal mixing, we calculated a Margules parameter ( W melt F ) of 48.6 ± 4.3 kJ/mol for F in silicate melt with a symmetric binary mixing model. The high value of W melt F confirms that O–F mixing in silicate melt is far from ideal. The reliability of using of D Ttn − melt F to calculate melt F contents has been checked by investigating plutonic rocks of the Liujiawa pluton in the Dabie orogen of eastern China. Our new estimates of melt F content are consistent with those derived from amphibole, biotite and apatite compositions.

Prediction and validation of double cross hybrids in maize (Zea mays L.)

The experiment comprised of six F1’s, which were selected based on the combinations of low yield × high yield and low ASI × high ASI. The selected six F1’s were crossed in full diallel mating design to synthesise 16 double crosses was estimated and validated on the basis of performance of their constituent single crosses. Out of 16 hybrids, DCH 15 recorded lower tasseling and silking days and hence it can be used further in breeding programme. While, DCH 13 recorded narrow mean for ASI are suggested for use in deriving superior inbred lines with a combination of narrow ASI and higher ear circumference and kernel rows ear-1.The expected yield performance of DCH 5 (125.88), DCH 8 (124.23), DCH 10 (123.96), DCH 15 (123.73), DCH 6 (122.77) and DCH 12 (120.76) out yielded best check, Hema (119.00) for grain yield plant-1respectively. DCH 12 predicted better for most of the characters viz., ASI, ear length, ear circumference, kernel rows-1 and 100 grain weight. While, DCH 15 predicted better for characters viz., days to tasseling, days to silking, plant height (cm), ear height (cm), kernels row-1 and shelling percentage. Therefore, these two crosses may be used as double cross hybrids for breeding programme. In both prediction methods, nearly 14 out of 16 double cross hybrids manifested significant differences between realised and predicted performance suggesting involvement of epistasis in genetic control of grain yield plant-1

High Periostin Expression is an Independent Positive Prognostic Factor in Pancreatic Ductal Adenocarcinoma

Fig. 5: The strongest expression is detected in the periacinar spaces. Fig. 6: Encasement of acini by the periostin-rich ECM High periostin expression (31.2 Mo vs. 14.9 Mo, p=0.006), low ASI (23.9 Mo vs. 14.8 Mo, p=0.009), T-Stage (T2/T3/T4: 42.7/21.5/10.6 Mo, p=0.031), metastasis to interaortocaval lymph nodes (22.5 Mo vs. 14.9 Mo, p=0.03) and grade of the tumor (G1/G2/G3: 34.2/22.4/15.1, p=0.044) were significant variables in single factor analysis.

The Soils of The Lower Asi River Basin

Bu calismada Asagi Asi Nehri havzasi topraklarinin olusum ve gelisimlerinde etkili olan faktorler, baslica toprak serileri (ordolari) ve bunlarin ozelikleri aciklanmasi amaclanmistir. Ilgili amac kapsaminda literatur esliginde degisik olceklerdeki farkli haritalardan ve cesitli verilerinden yararlanilmistir. Bunun akabinde havza alaninda arazi calismalari yapilmis ve toprak ornekleri alinarak, analiz edilmistir. Daha sonraki adimda butun bu veriler Cografi Bilgi Sistemleri (CBS) teknikleri ile tematik haritalara donusturulmus ve metne aktarilmistir. Sonucta havza alaninda topraklarin olusum ve gelisiminde basta iklim, jeomorfolojik ozellikler ve ana materyal olmak uzere bircok faktorun etkili oldugu gorulmustur. Bu baglamda havza alaninda Alfisol, Andisol, Entisol, Histosol, Inceptisol, Mollisol ve Vertisol turunde topraklarin dagilis gosterdigi anlasilmistir. En yaygin toprak serilerinin ise genclik veya ergenlik safhasinda olan Entisol ve Inceptisol oldugu belirlenmistir. Havza alaninda siltli balcik ve killi balcik en yaygin toprak tekstur siniflarini olusturmaktadir. Bu durum havzada genel itibariyle agir bunyeli topraklarin hakim oldugunu yansitmaktadir

LA-ICP MS zircon dating, whole-rock and Sr–Nd–Pb–O isotope geochemistry of the Camiboğazı pluton, Eastern Pontides, NE Turkey: Implications for lithospheric mantle and lower crustal sources in arc-related I-type magmatism

Late Cretaceous I-type plutons are widespread in the Eastern Pontides, NE Turkey. The studied Camiboğazı pluton is a composite pluton consisting of diorite, tonalite, monzodiorite, monzonite, quartz monzonite, granite, and mafic microgranular enclaves (MMEs). Laser ablation ICP-MS U–Pb dating of zircon yielded crystallization ages of 76.21±0.79Ma, 75.65±0.50Ma, 75.04±0.83Ma, and 74.73±0.86Ma for diorite, monzodiorite, monzonite, and granite, respectively. The rocks of the pluton have I-type, high-K to shoshonitic and metaluminous character, displaying whole-rock geochemical features of arc-related granites. They are enriched in large-ion lithophile and light rare-earth elements, and depleted in high-field-strength elements. Major element variations can be attributed to fractionation of plagioclase, clinopyroxene, hornblende, and Fe–Ti oxides. The rocks show considerable variation in 87Sr/86Sr(i) (0.70498 to 0.70622), εNd(i) (−2.79 to −0.36), δ18O values (+6.3 to +11.4) and Nd model ages (TDM) (0.81Ga to 1.26Ga). Besides, they have (206Pb/204Pb)=18.44–19.09, (207Pb/204Pb)=15.64–15.69, and (208Pb/204Pb)=38.37–38.89. Although isotope signatures of the mafic microgranular enclaves (MMEs) (87Sr/86Sr(i)=0.70551 to 0.70622; εNd(i)=−2.9 to −1.23; δ18O=+8.3 to +9.7) are largely similar to the host rocks, MMEs are characterized by relatively high Mg-numbers (32–36), low contents of SiO2 (52–56wt.%) and low ASI (0.7–0.9). Estimated crystallization temperatures for the rocks of the pluton range from 735±58°C to 844±24°C and a shallow intrusion depth (<10km) is estimated from Al-in-hornblende thermobarometry. Whole-rock geochemical and isotopic data suggest magma generation by dehydration melting of an amphibolite-type lower crustal component with additional input of a subcontinental lithospheric mantle component. Furthermore, Sr–Nd isotope mixing model reveals ~30% to 40% lower crustal magma contribution to the mantle component.

The influence of composition on the local structure around yttrium in quenched silicate melts — Insights from EXAFS

The structural environment around Y in silicate and aluminosilicate glasses containing 5000ppm Y was investigated as a function of melt composition and polymerization using Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. The used glass compositions were taken from Prowatke and Klemme (2005) varying in the aluminum saturation index (ASI, molar ratio of Al2O3/(Na2O+K2O+CaO)) from 0.115 to 0.768. Furthermore, a set of glass compositions from the system CaO–Al2O3–SiO2 (CAS) was used, for which structural data from computer simulations are available (Haigis et al., 2013--this issue). Structural parameters of the Y–O pair correlation of the first coordination shell were determined from the EXAFS based on a gamma-like distribution function that accounts for the large static disorder and non-Gaussian pair distributions. The analysis shows an increase in the coordination number from 6 to 8, along with an increase of the average Y–O distance by 0.13Å for the composition of Prowatke and Klemme (2005). For the CAS-composition an increase of the coordination number from 6 to 7, along with an increase of the average Y–O distance by 0.06Å is obtained. The change of these parameters is associated with a considerable increase in the asymmetry and width of the Y–O pair distribution. Due to its size and charge, 6-fold coordinated Y will preferentially bond to non-bridging oxygens of the polymeric melt network to form a stable configuration, as is the case for the less polymerized melts with low ASI. In highly polymerized melts with ASI values close to one, 6-fold coordination of Y is not possible because almost only bridging oxygens are available. Consequently, over-bonding of bridging oxygens around Y is counterbalanced by an increase of coordination number and Y–O distance to satisfy local charge balance requirements.

Are Shock Index and Adjusted Shock Index useful in predicting mortality and length of stay in community-acquired pneumonia?

Background Community Acquired Pneumonia (CAP) is a common infection which is associated with a significant mortality. Shock index, heart rate divided by blood pressure, has been shown to predict mortality in several conditions including sepsis, acute myocardial infarction and traumatic injuries. Very little is known about the prognostic value of shock index in community acquired pneumonia (CAP). Objective To examine the usefulness of shock index (SI) and adjusted shock index (corrected to temperature) (ASI) in predicting mortality and hospital length of stay in patients admitted to hospital with CAP. Methods A prospective study was conducted in three hospitals in Norfolk & Suffolk, UK. We compared risk of mortality and longer length of stay for low (=<1.0, i.e. heart rate =< systolic BP) and high (> 1.0, i.e. heart rate > systolic BP) SI and ASI adjusting for age, sex and other parameters which have been shown to be associated with mortality in CAP. Results A total of 190 patients were included (males = 53%). The age range was 18–101 years (median = 76 years). Patients with SI & ASI > 1.0 had higher likelihood of dying within 6 weeks from admission. The adjusted odds ratio for 30 days mortality were 2.48 (1.04–5.92; p = 0.04) for SI and 3.16 (1.12–8.95; p = 0.03) for ASI. There was no evidence to suggest that they predict longer length of stay. Conclusion Both SI and ASI of > 1.0 predict 6 weeks mortality but not longer length of stay in CAP.

Environmental and Genetic Control of Arsenic Accumulation and Speciation in Rice Grain: Comparing a Range of Common Cultivars Grown in Contaminated Sites Across Bangladesh, China, and India

The concentration of arsenic (As) in rice grains has been identified as a risk to human health. The high proportion of inorganic species of As (As(i)) is of particular concern as it is a nonthreshold, class 1 human carcinogen. To be able to breed rice with low grain As, an understanding of genetic variation and the effect of different environments on genetic variation is needed. In this study, 13 cultivars grown at two field sites each in Bangladesh, India, and China are evaluated for grain As. There was a significant site, genotype, and site by genotype interaction for total grain As. Correlations were observed only between sites in Bangladesh and India, not between countries or within the Chinese sites. For seven cultivars the As was speciated which revealed significant effects of site, genotype, and site by genotype interaction for percentage As(i). Breeding low grain As cultivars that will have consistently low grain As and low As(i), over multiple environments using traditional breeding approaches may be difficult, although CT9993-5-10-1-M, Lemont, Azucena, and Te-qing in general had low grain As across the field sites.

A Rhyolite Compositional Continuum Governed by Lower Crustal Source Conditions in the Taupo Volcanic Zone, New Zealand

Rhyolites generated in the modern Taupo Volcanic Zone (TVZ), New Zealand, have previously been interpreted as having evolved by a combination of extensive fractional crystallization of mantle-derived mafic magmas and limited crustal assimilation (up to 25%). Polytopic vector analysis (PVA), a form of multivariate statistical analysis, of the major-element compositions of over 475 basaltic to rhyolitic bulk-rock samples, representing over 600 kyr of volcanism within the TVZ, has provided a robust platform for rhyolite characterization and new insights into rhyolite petrogenesis. There is a continuum of compositions between two rhyolite end-member magma types (EM1 and EM2), which have been identified on the basis of the PVA and which have distinct petrological and geochemical characteristics, as follows. EM1: crystal-rich (up to 45%), hydrous phases (± hornblende ± biotite ± cummingtonite), high Aluminum Saturation Index [ASI; molar Al 2 O 3 /(CaO + Na 2 O + K 2 O)], low FeO*/MgO (calc-alkaline series), depleted abundances of middle rare earth elements (MREE) and Y, and high Sr; EM2: crystal-poor (<10%), anhydrous phases (orthopyroxene ± clinopyroxene), high FeO*/MgO (tholeiitic series), low ASI, less depleted MREE and Y, and low Sr. The range of ASI values, and relative depletion in MREE and Y in the rhyolites is consistent with the results of experiments to constrain the partial melting behaviour of amphibolite at crustal pressures. The major- and trace-element data are also consistent with 50-60% equilibrium crystallization of a crustally contaminated, hornblende-bearing andesite to produce the TVZ rhyolites. Distinct major- and trace-element variations along the continuum between the two rhyolite end-member types can be effectively modelled by simulating changes in the temperature-fO 2 -fH 2 O conditions in the lower crust where mantle-derived mafic magmas are stored and differentiate. Low T and high fO 2 and fH 2 O in the crustal magma storage zone promote abundant hornblende crystallization and suppress plagioclase crystallization, which produces the EM1 type rhyolite. By increasing the temperature and/or lowering fO 2 and fH 2 O in the magma storage region, plagioclase becomes more dominant and hornblende crystallization is suppressed, producing more EM2-like rhyolitic magma types.

Mineralogy, whole-rock and Sr–Nd isotope geochemistry of mafic microgranular enclaves in Cretaceous Dagbasi granitoids, Eastern Pontides, NE Turkey: Evidence of magma mixing, mingling and chemical equilibration

Rocks of the Late Cretaceous Dagbasi Pluton (88–83 Ma), located in the eastern Pontides, include mafic microgranular enclaves (MMEs) ranging from a few centimetres to metres in size, and from ellipsoidal to ovoid in shape. The MMEs are composed of gabbroic diorite, diorite and tonalite, whereas the felsic host rocks comprise mainly tonalite, granodiorite and monzogranite based on both mineralogical and chemical compositions. MMEs are characterized by a fine-grained, equigranular and hypidiomorphic texture. The common texture of felsic host rocks is equigranular and also reveals some special types of microscopic textures, e.g., oscillatory-zoned plagioclase, poikilitic K-feldspar, small lath-shaped plagioclase in large plagioclase, blade-shaped biotite, acicular apatite, spike zones in plagioclase and spongy-cellular plagioclase textures and rounded plagioclase megacrysts in MMEs. Compositions of plagioclases (An 33–An 60), hornblendes (Mg#=0.77–1.0) and biotites (Mg#=0.61–0.63) of MMEs are slightly distinct or similar to those of host rocks (An 12–57; hbl Mg#=0.63–1.0; Bi Mg#=0.50–0.69), which suggest partial to complete equilibration during mafic–felsic magma interactions. The felsic host rocks have SiO 2 between 60 and 76 wt% and display low to slightly medium-K tholeiitic to calc-alkaline and peraluminous to slightly metaluminous characteristics. Chondrite-normalized rare-earth element (REE) patterns are fractionated (La cn/Lu cn=1.5–7.3) with pronounced negative Eu anomalies (Eu/Eu*=0.46–1.1). Initial ε Nd(i) values vary between −3.1 and 1.6, initial 87Sr/ 86Sr values between 0.7056 and 0.7067. Compared with the host rocks, the MMEs are characterized by relatively high Mg-number of 22–52, low contents of SiO 2 (53–63 wt%), low ASI (0.7–1.1) and low to medium-K tholeiitic to calc-alkaline, metaluminous to peraluminous composition. Chondrite-normalized REE patterns are relatively flat [(La/Yb) cn=1.4–3.9; (Tb/Yb) cn=0.9–1.5] and show small negative Eu anomalies (Eu/Eu*=0.63–1.01). Isotope signatures of these rocks ( 87Sr/ 86Sr (i)=0.7054–0.7055; ε Nd(i)=–1.0 to 1.9) are largely similar to the host rocks. Gabbroic diorite enclaves have relatively low contents of SiO 2, ASI; high Mg#, CaO, Al 2O 3, TiO 2, P 2O 5, Sr and Nb concentrations compared to dioritic and tonalitic enclaves. The geochemical and isotopic similarities between the MMEs and their host rocks indicate that the enclaves are of mixed origin and are most probably formed by the interaction between the lower crust- and mantle-derived magmas. All the geochemical data suggest that a basic magma derived from an enriched subcontinental lithospheric mantle, interacted with a crustal melt that originated from dehydration melting of the mafic lower crust at deep crustal levels. The existence of compositional and textural disequilibrium and the nature of chemical and isotopic variation in these rock types indicate that magma mixing/mingling between an evolved mafic and a granitic magma was involved in their genesis. Microgranular enclaves are thus interpreted to be globules of a more mafic magma probably from an enriched lithospheric mantle source. Al-in-amphibole estimates the pluton emplacement at ca. 0.3–3.8 kbar, and therefore, magma mixing and mingling must have occurred at 3.8 kbar or below this level.

PROVENIÊNCIA E AMBIENTAÇÃO TECTÔNICA DE METASSEDIMENTOS DE ALTO GRAU: NAPPE TRÊS PONTAS-VARGINHA, SUL DO CRÁTON SÃO FRANCISCO

Samples of granulite- to amphibolite-facies metasedimentary rocks of the Três Pontas-Varginha Nappe, south of São Francisco Craton, were analised. The results indicated that the kyanite-bearing gneisses from the base of the nappe, Três Pontas area, can be divided in two groups with different chemical characteristics. The first one presents high SiO 2 /Al 2 O 3 , ratios (3.28-4.69), low K 2 /Na 2 O (0.45- 1.06) ratios, and low IAQ values (48-60). The second group exhibits high and varied SiO 2 /Al 2 O 3 ratios (2.55-4.71) and high K 2 O/Na 2 O ratios (2.30-11.71), probably constituting products of relatively pure pelitic sediments. The ASI values are high (67-79) and suggestive of a long weathering period marked by intense chemical weathering. Passive margin settings or, alternatively, old crustal sources are the most probable origin for these sediments. The upper unit of kyanitc/sillimanite-bearing gnesseis from the Varginha area are more homogeneous and show high SiO 2 /AlO 3 ratios (3.03-4.59) and relatively low K 2 O/Na 2 O ratios (0.23-2.48), which suggest an origin from feldspar-rich psamitic sediments, probably wackes. The low ASI values (5 1-65) indicate that rocks from the source area were lesser affected by chemical weathering, suggesting a general prevalence of physical weathering or other short-termed weathering processes. These characteristics are compatible with post-Archean active margin settings.

Proveniência e ambientação tectônica de metassedimentos de alto grau: nappe três pontas-varginha, sul do Cráton São Francisco

Samples of granulite- to amphibolite-facies metasedimentary rocks of the Tres Pontas-Varginha Nappe, south of Sao Francisco Craton, were analised. The results indicated that the kyanite-bearing gneisses from the base of the nappe, Tres Pontas area, can be divided in two groups with different chemical characteristics. The first one presents high SiO 2 /Al 2 O 3 ratios (3.28-4.69), low K 2 O/Na 2 O (0.45-1.06) ratios, and low IAQ values (48-60). The second group exhibits high and varied SiO 2 /Al 2 O 3 ratios (2.55-4.71) and high K 2 O/Na 2 O ratios (2.30-11.71), probably constituting products of relatively pure pelitic sediments. The ASI values are high (67-79) and suggestive of a long weathering period marked by intense chemical weathering. Passive margin settings or, alternatively, old crustal sources are the most probable origin for these sediments. The upper unit of kyanite/sillimanite-bearing gneisses from the Varginha area are more homogeneous and show high SiO 2 /Al 2 O 3 ratios (3.03-4.59) and relatively low K 2 O/Na 2 O ratios (0.23-2.48), which suggest an origin from feldspar-rich psamitic sediments, probably wackes. The low ASI values (51-65) indicate that rocks from the source area were lesser affected by chemical weathering, suggesting a general prevalence of physical weathering or other short-termed weathering processes. These characteristics are compatible with post- Archean active margin settings.

Fearful responding to repeated CO 2 inhalation: A preliminary investigation

In an effort to explore factors which maintain fear of physical sensations, repeated administration of 35% CO 2 was used with college students scoring high and low on the Anxiety Sensitivity Index. Half of each group was administered 12 CO 2 trials, while the other half received 9 CO 2 trials, followed by a dishabituation trial (Trial 10) and 2 more CO 2 administrations (Trials 11 and 12). Measures included subjective anxiety, heart rate, skin conductance, and number of panic symptoms reported. Results indicated a nonsignificant trend for the High ASI group to show increased pre-inhalation anxiety across trials, while the Low ASI group showed a rapid reduction in pre-inhalation anxiety. Post-inhalation skin conductance mirrored this pattern, although rapid reduction in post-inhalation heart rate was observed. Overall, the High ASI participants showed a notable lack of fear reduction across trials. Results are discussed in light of sensitization as a factor contributing to anticipatory anxiety, with implications for understanding the etiology and maintenance of Panic Disorder.

Anxiety sensitivity, state anxiety and perceptions of facial emotions

We investigated relationships between anxiety sensitivity and perceptions of facial emotions following relaxation and hyperventilation. The Anxiety Sensitivity Index was administered to 606 female college undergraduates and samples of high ( n = 30) and low ( n = 25) scorers were obtained from the top and bottom 15% of the distribution. Following exposure to randomly counterbalanced 5-minute relaxation and hyperventilation instructions, participants rated the intensity of seven basic emotions in photographs of faces using a standardized test of affect-receiving ability. High ASI scorers perceived significantly more intense fear and anger than did low ASI respondents and reported relatively larger increases in ratings of sadness and fear following hyperventilation. ASI was significantly correlated with heightened state anxiety and vigilance prior to beginning the experiment, and these affects mediated interpersonal perceptions. Results suggest that high ASI scorers may manifest a chronic state of vigilance that triggers heightened anxiety in ambiguous situations. The combination of high anxiety sensitivity and state anxiety appears to foster greater sensitivity to interpersonal stimuli.