Search results for "cycle"

2012

Abstract. Mineral dust is a major fraction of global atmospheric aerosol, and the oxidation of SO2 on mineral dust has implications for cloud formation, climate and the sulfur cycle. Stable sulfur isotopes can be used to understand the different oxidation processes occurring on mineral dust. This study presents measurements of the 34S/32S fractionation factor α34 for oxidation of SO2 on mineral dust surfaces and in the aqueous phase in mineral dust leachate. Sahara dust, which accounts for ~60% of global dust emissions and loading, was used for the experiments. The fractionation factor for aqueous oxidation in dust leachate is αleachate = 0.9917±0.0046, which is in agreement with previous m…

The impact of geoengineering on vegetation in experiment G1 of the GeoMIP

2015

Solar Radiation Management (SRM) has been proposed as a mean to partly counteract global warming. The Geoengineering Model Intercomparison Project (GeoMIP) has simulated the climate consequences of a number of SRM techniques. Thus far, the effects on vegetation have not yet been thoroughly analyzed. Here the vegetation response to the idealized GeoMIP G1 experiment from eight fully coupled Earth system models (ESMs) is analyzed, in which a reduction of the solar constant counterbalances the radiative effects of quadrupled atmospheric CO2 concentrations (abrupt4 × CO2). For most models and regions, changes in net primary productivity (NPP) are dominated by the increase in CO2, via the CO2 fe…

2012

Abstract. The oxidation of SO2 to sulfate on sea salt aerosols in the marine environment is highly important because of its effect on the size distribution of sulfate and the potential for new particle nucleation from H2SO4 (g). However, models of the sulfur cycle are not currently able to account for the complex relationship between particle size, alkalinity, oxidation pathway and rate – which is critical as SO2 oxidation by O3 and Cl catalysis are limited by aerosol alkalinity, whereas oxidation by hypohalous acids and transition metal ions can continue at low pH once alkalinity is titrated. We have measured 34S/32S fractionation factors for SO2 oxidation in sea salt, pure water and NaOCl…

Accelerated Changes of Environmental Conditions on the Tibetan Plateau Caused by Climate Change

2011

Abstract Variations of land surface parameters over the Tibetan Plateau have great importance on local energy and water cycles, the Asian monsoon, and climate change studies. In this paper, the NOAA/NASA Pathfinder Advanced Very High Resolution Radiometer (AVHRR) Land (PAL) dataset is used to retrieve the land surface temperature (LST), the normalized difference vegetation index (NDVI), and albedo, from 1982 to 2000. Simultaneously, meteorological parameters and land surface heat fluxes are acquired from the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) dataset and the Global Land Data Assimilation System (GLDAS), respectively. Results show that from …

The Influence of Land Surface Temperature in Evapotranspiration Estimated by the S-SEBI Model

2020

Evapotranspiration (ET) is one of the least understood components of the hydrological cycle. Its applications are varied, from agricultural, ecological and hydrological monitoring, to control of the evolution of climate change. The goal of this work was to analyze the influence that uncertainties in the estimate of land surface temperature (Ts) can cause on ET estimates by S-SEBI model in the Pampa biome area. Also, the specificities of native grassland of Pampa biome related to energy balance were analyzed. The results indicate that the daily evapotranspiration is higher when the pixel Ts is lower, which also shows the influence of land use on the variability of ET. The results demonstrate…

Storage and release of false transmitters after infusion of (+)- and (?)-?-methyldopamine

1971

Rabbits were given an infusion of 10 mg/kg (−)- or 30 mg/kg (+)-α-methyldopamine and killed after 135 min. The noradrenaline content of the heart was decreased to 26±5 and 34±2%, respectively, of the control value. After infusion of the (+)-isomer the missing noradrenaline was replaced by (−)-α-methylnoradrenaline. Electrical stimulation of the sympathetic nerves or infusion of acetylcholine plus atropine caused an output of noradrenaline and (−)-α-methylnoradrenaline from the isolated heart. The two amines were released in the same proportion as they were stored in the heart and the total output of both amines equalled the output of noradrenaline from control hearts. Nerve stimulation caus…

Male steroid hormones and female preference for male body odor

2006

It has been suggested that human scent works as a signal in mate selection, but the empirical evidence is scarce. Here, we examined whether women’s olfactory preferences for a man’s scent could be correlated with his testosterone, estradiol, or cortisol concentrations, and whether these preferences change along with the menstrual cycle. In line with previous studies, women in their most fertile period gave the highest attractiveness ratings to all men. However, the intensity ratings by women at different menstrual phases did not significantly differ statistically. Interestingly, we found that cortisol concentration in saliva correlated positively with the attractiveness but not with the int…

Height predicts jealousy differently for men and women

2008

Because male height is associated with attractiveness, dominance, and reproductive success, taller men may be less jealous. And because female height has a curvilinear relationship with health and reproductive success (with average-height females having the advantages), female height may have a curvilinear relationship with jealousy. In Study 1, male height was found to be negatively correlated with self-reported global jealousy, whereas female height was curvilinearly related to jealousy, with average-height women reporting the lowest levels of jealousy. In Study 2, male height was found to be negatively correlated with jealousy in response to socially influential, physically dominant, and…

Attractors/Basin of Attraction

2020

It is a controversial issue to decide who first coined the term “attractor”. According to Peter Tsatsanis, the editor of the English version of Prédire n’est pas expliquer, it was René Thom who first introduced such a term. It is necessary, however, to remember that Thom thought that it was first introduced by the American mathe- matician Steven Smale, “although Smale says it was Thom that coined the neolo- gism “attractor”“(Tsatsanis 2010: 63–64 n. 20). From this point of view, Bob Williams expressed a more cautious opinion by saying that “the word “attractor” was invented by these guys, Thom and Smale” (Cucker and Wong 2000: 183). But other mathematicians are of the opinion that the term …

Corrosion Resistance of Alloys in IGCC Environment

2001

IGCC recovery boiler materials are subject to severe corrosion in environments composed of a gas mixture (CO-H 2 -H 2 O-CO 2 -H 2 S) and vanadium-containing fly-ash resulting from the combustion of oil residues. This paper presents a study of the corrosion behaviour of two Fe-Ni-Cr austenitic alloys in a typical IGCC environment at 400°C. The alloy composition influences the vanadium incorporated in the corrosion scales during the test, which affects the scale growth process. The valence state (determined by micro-XANES) and the amount of the incorporated vanadium is modified by a subsequent air flow at 400°C.