Orbital Observations of Dust Lofted by Daytime Convective Turbulence

Over the past several decades, orbital observations of lofted dust have revealed the importance of mineral aerosols as a climate forcing mechanism on both Earth and Mars. Increasingly detailed and diverse data sets have provided an ever-improving understanding of dust sources, transport pathways, and sinks on both planets, but the role of dust in modulating atmospheric processes is complex and not always well understood. We present a review of orbital observations of entrained dust on Earth and Mars, particularly that produced by the dust-laden structures produced by daytime convective turbulence called “dust devils”. On Earth, dust devils are thought to contribute only a small fraction of the atmospheric dust budget; accordingly, there are not yet any published accounts of their occurrence from orbit. In contrast, dust devils on Mars are thought to account for several tens of percent of the planet’s atmospheric dust budget; the literature regarding martian dust devils is quite rich. Because terrestrial dust devils may temporarily contribute significantly to local dust loading and lowered air quality, we suggest that martian dust devil studies may inform future studies of convectively-lofted dust on Earth

Development and evaluation of on-line detection techniques for polar organics in ultrapure water

An on-line monitor that can perform rapid, trace detection of polar organics such as acetone and isopropanol in ultrapure water (UPW) is necessary to efficiently recycle water in semiconductor manufacturing facilities. The detection of these analytes is problematic due to their high solubility in water, resulting in low partitioning into sensor coatings for direct water analysis or into the vapor phase for detection by vapor phase analyzers. After considering various options, we have evaluated two conventional laboratory techniques: gas chromatography and ion mobility spectroscopy. In addition, optimizations of sensor coating materials and sample preconditioning systems were performed with the goal of a low cost, chemical sensor system for this application. Results from these evaluations, including recommendations for meeting the needs of this application, are reported

Philosophical conceptions of information

“The original publication is available at www.springerlink.com” Copyright Springer'I love information upon all subjects that come in my way, and especially upon those that are most important.' Thus boldly declares Euphranor, one of the defenders of Christian faith in Berkley’s Alciphron (Berkeley, (1732), Dialogue 1, Section 5, Paragraph 6/10). Evidently, information has been an object of philosophical desire for some time, well before the computer revolution, Internet or the dot.com pandemonium (see for example Dunn (2001) and Adams (2003)). Yet what does Euphranor love, exactly? What is information? The question has received many answers in different fields. Unsurprisingly, several surveys do not even converge on a single, unified definition of information (see for example Braman 1989, Losee (1997), Machlup and Mansfield (1983), Debons and Cameron (1975), Larson and Debons (1983)).Peer reviewe

Is estradiol cardioprotection a nitric oxide-mediated effect?

BACKGROUND: Estradiol exerts a number of biological effects that support extensive observational data suggesting a protective role for estrogen in cardiovascular disease prevention. These include effects on lipid and carbohydrate metabolism, coagulation/fibrinolysis as well as a possible effect on vascular reactivity. It has been proposed that this might be mediated by vascular endothelial nitric oxide (NO) production. Accordingly, we designed complementary in-vivo and in-vitro studies to investigate this hypothesis further.<p></p> METHODS: Firstly, in a group of 10 healthy post-menopausal women, bilateral venous occlusion plethysmography was used to examine forearm vasoconstrictor responses to intrabrachial N-G-monomethyl-l-arginine (l-NMMA; a substrate inhibitor of nitric oxide synthase) both before and after 4 weeks of treatment with transdermal 17beta-estradiol (E-2) (80 mug/day). Secondly, we examined the direct effects of acute (24 h) and chronic (7 days) treatment with E-2 (10 pmol/l and 10 nmol/l) on endothelial nitric oxide synthase (eNOS) gene expression in cultured human aortic endothelial cells.<p></p> RESULTS: No significant differences were observed between the vasoconstrictor responses to l-NMMA (2, 4, 8 mumol/min) before and after E-2 treatment. Comparison of E-2-treated endothelial cells with control cells showed no significant increase in eNOS mRNA expression following either acute or chronic estradiol treatment.<p></p> CONCLUSIONS: The present studies do not provide evidence for an eNOS-mediated cardioprotective response to estrogen and therefore suggest that additional mechanisms other than the endothelial NO system may have an important role in the cardiovascular effects of estrogen.<p></p&gt