Fluorescence Analysis for Multi-Site Aluminum Binding to Natural Organic Matter

Natural organic matter (NOM) samples isolated from different water sources in Norway were compared using their fluorescence properties. Fluorescence surfaces were observed at pH 4.36 and deconvoluted using SIMPLISMA (Windig and Guilment 1991). There were a total of seven different fluorophores observed for these samples and each sampling site had between four and six ofthe fluorescent components. These components were observed to bind Al during titrations at the same pH. Multiresponse titration curves were fit using the method of Smith and Kramer (1998) and most of the binding strengths are similar to values for Suwannee River fulvic acid (1ogK’ between 4.8 and 5.5), but there are strong sites (IogK’ = 7) and weak sites (1ogK’ between 3 and 4) also observed. Results depended on the isolation method used; reverse osmosis and low pressure evaporation yielded different values but with no consistent trends

Fluorescence Analysis for Multi-Site Aluminum Binding to Natural Organic Matter

Natural organic matter (NOM) samples isolated from different water sources in Norway were compared using their fluorescence properties. Fluorescence surfaces were observed at pH 4.36 and deconvoluted using SIMPLISMA (Windig and Guilment 1991). There were a total of seven different fluorophores observed for these samples and each sampling site had between four and six ofthe fluorescent components. These components were observed to bind Al during titrations at the same pH. Multiresponse titration curves were fit using the method of Smith and Kramer (1998) and most of the binding strengths are similar to values for Suwannee River fulvic acid (1ogK’ between 4.8 and 5.5), but there are strong sites (IogK’ = 7) and weak sites (1ogK’ between 3 and 4) also observed. Results depended on the isolation method used; reverse osmosis and low pressure evaporation yielded different values but with no consistent trends

Multi-site Proton Interactions with Natural Organic Matter

Water samples from various locations in Norway were used to isolate natural organic matter (NOM). The NOM was isolated using both reverse osmosis and low-pressure low-temperature evaporation for each sample site. These samples were titrated from -log[H+] 3 to 11 at 0.1 unit intervals. The data were analyzed using the Discrete Site Analysis (DISI) technique for pKa intervals of 0.2. The acidity constants are grouped into four classes: strong (pKa \u3c 5), intermediate strong (5.1\u3c pKa \u3c 7.5), intermediate weak (7.6 \u3c pKa \u3c 9.2), and weak (pKa \u3e 9.3). All samples, regardless of isolation method, were found to contain strong and weak ligands, along with some intermediate ligands. For the same sample site, the concentration of these ligands were found to be dependent on isolation method and titration direction (acid then base vs. base then acid). In addition, the concentration and classes of ligands present were found to vary between sample sites. Suwannee River fulvic acid was analyzed as a reference sample, and was qualitatively similar to the NOM samples but quantitatively different. Overall, the differences in pKa spectra due to isolation method and/or titration direction are almost as significant as differences between sample location, but there are no consistent trends in effects of isolation method or titration direction on characterization of NOM

NEOWISE: Observations of the Irregular Satellites of Jupiter and Saturn

We present thermal model fits for 11 Jovian and 3 Saturnian irregular satellites based on measurements from the WISE/NEOWISE dataset. Our fits confirm spacecraft-measured diameters for the objects with in situ observations (Himalia and Phoebe) and provide diameters and albedo for 12 previously unmeasured objects, 10 Jovian and 2 Saturnian irregular satellites. The best-fit thermal model beaming parameters are comparable to what is observed for other small bodies in the outer Solar System, while the visible, W1, and W2 albedos trace the taxonomic classifications previously established in the literature. Reflectance properties for the irregular satellites measured are similar to the Jovian Trojan and Hilda Populations, implying common origins.Comment: 17 pages, 3 figures, accepted for publication in Astrophysical Journa

History of sea water. Constant temperature-pressure equilibrium models compared to liquid inclusion analyses

An inorganic ocean is derived from the solution equilibrium of clay minerals, calcite, OH-apatite, CO2-F-apatite, phillipsite, gypsum, strontianite, celestite and aragonite. The minerals are considered in equilibrium in different combinations with and without chloride.A "most probable" model for the major ions has concentrations very close to modern sea water; an "upper limit", model has concentrations slightly higher than modern sea water except that Mg and SO4 are 5 to 6 times higher than modern ocean concentrations. A "lower limit" model is quite similar to "fresh" water. The presence or absence of Cl seems to be the most important factor in determining "fresh" or saline water concentrations. It is suggested that very ancient ocean waters may have been quite similar in composition and concentration to modern "fresh" water environments.Liquid inclusion analyses from salt and chert from the Silurian Salina and Niagaran Groups of Michigan, Ontario, Ohio and Wisconsin compare very favorably with modern ocean compositions except that Ca and Mg compositions appear to be reversed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32001/1/0000043.pd

Association of the Tobacco mosaic virus 126kDa replication protein with a GDI protein affects host susceptibility

AbstractAn interaction between the Tobacco mosaic virus (TMV) 126kDa replication protein and a host-encoded Rab GDP dissociation inhibitor (GDI2) was identified and investigated for its role in infection. GDI proteins are essential components of vesicle trafficking pathways. TMV infection alters the localization of GDI2 from the cytoplasm to ER-associated complexes. Partial silencing of GDI2 results in significant increases in the number of TMV infection foci observed in inoculated tissues. However, GDI2 silencing does not affect TMV accumulation at the infection site, cell-to-cell movement, or susceptibility of the host to mechanical inoculation. Furthermore, increases in the number of successful infection foci were specific to TMV and correlated with the appearance of vesicle-like rearrangements in the vacuolar membrane. Tissue infiltrations with brefeldin A, an inhibitor of vesicle trafficking, also enhanced host susceptibility to TMV. Combined these findings suggest that the 126kDa–GDI2 interaction alters vesicle trafficking to enhance the establishment of an infection

The infuence of glycosidic linkage neighbors on disaccharide conformation in vacuum

Correct description of the free energy of conformation change of disaccharides is important in understanding a variety of biochemical processes and, ultimately, in the manufacture of better food and paper products. In this study, we determine the relative free energy of a series of 12 disaccharides in vacuum using replica exchange molecular dynamics (repMD) simulations. The chosen sugars and the novel application of this method allow the exploration of the role of glycosidic linkage neighbors in conformer stabilization. In line with expectations, we find that hydrogen bonding (and therefore energetically preferred conformations) are determined both by the nature of the glycosidic linkage (i.e., 1 f 2, 1 f 3, or 1 f 4), the C1 epimer of the of the nonreducing monosaccharide, and by the configuration of carbon atoms once removed from the glycosidic linkage. Contrary to suggestions by prior authors for repMD more generally, we also demonstrate that repMD provides enhanced sampling, relative to conventional MD simulations of equivalent length, for disaccharides in vacuum at 300 K.Fundação para a Ciência e a Tecnologia (FCT)SFRH/BPD/20555/2004/0GVLNational Science Foundation under Grant CHE-043132

The Large and Small Scale Structures of Dust in the Star-Forming Perseus Molecular Cloud

We present an analysis of ~3.5 square degrees of submillimetre continuum and extinction data of the Perseus molecular cloud. We identify 58 clumps in the submillimetre map and we identify 39 structures (`cores') and 11 associations of structures (`super cores') in the extinction map. The cumulative mass distributions of the submillimetre clumps and extinction cores have steep slopes (alpha ~ 2 and 1.5 - 2 respectively), steeper than the Salpeter IMF (alpha = 1.35), while the distribution of extinction super cores has a shallow slope (alpha ~ 1). Most of the submillimetre clumps are well fit by stable Bonnor-Ebert spheres with 10K < T < 19K and 5.5 < log_10(P_ext/k) < 6.0. The clumps are found only in the highest column density regions (A_V > 5 - 7 mag), although Bonnor-Ebert models suggest that we should have been able to detect them at lower column densities if they exist. These observations provide a stronger case for an extinction threshold than that found in analysis of less sensitive observations of the Ophiuchus molecular cloud. The relationship between submillimetre clumps and their parent extinction core has been analyzed. The submillimetre clumps tend to lie offset from the larger extinction peaks, suggesting the clumps formed via an external triggering event, consistent with previous observations.Comment: 38 pages, 12 figures, accepted by Astrophysical Journal slight changes to original due to a slight 3" error in the coordinates of the SCUBA ma

Information Management to Mitigate Loss of Control Airline Accidents

Loss of control inflight continues to be the leading contributor to airline accidents worldwide and unreliable airspeed has been a contributing factor in many of these accidents. Airlines and the FAA developed training programs for pilot recognition of these airspeed events and many checklists have been designed to help pilots troubleshoot. In addition, new aircraft designs incorporate features to detect and respond in such situations. NASA has been using unreliable airspeed events while conducting research recommended by the Commercial Aviation Safety Team. Even after significant industry focus on unreliable airspeed, research and other evidence shows that highly skilled and trained pilots can still be confused by the condition and there is a lack of understanding of what the associated checklist(s) attempts to uncover. Common mode failures of analog sensors designed for measuring airspeed continue to confound both humans and automation when determining which indicators are correct. This paper describes failures that have occurred in the past and where/how pilots may still struggle in determining reliable airspeed when confronted with conflicting information. Two latest generation aircraft architectures will be discussed and contrasted. This information will be used to describe why more sensors used in classic control theory will not solve the problem. Technology concepts are suggested for utilizing existing synoptic pages and a new synoptic page called System Interactive Synoptic (SIS). SIS details the flow of flight critical data through the avionics system and how it is used by the automation. This new synoptic page as well as existing synoptics can be designed to be used in concert with a simplified electronic checklist (sECL) to significantly reduce the time to configure the flight deck avionics in the event of a system or sensor failure

Dust emissivity in the Submm/Mm: SCUBA and SIMBA observations of Barnard 68

We have observed the dark cloud Barnard 68 with SCUBA at 850 um and with SIMBA at 1.2 mm. The submillimetre and millimetre dust emission correlate well with the extinction map of Alves, Lada and Lada (2001).The A_V/850um correlation is clearly not linear and suggests lower temperatures for the dust in the inner core of the cloud. Assuming a model for the temperature gradient, we derive the cloud-averaged dust emissivities (normalised to the V-Band extinction efficiency) at 850 um and 1.2 mm. We find k_850um/k_V = 4.0 +/- 1.0 x 10^-5 and k_1.2mm/k_V = 9.0 +/- 3.0 x 10^-6. These values are compared with other determinations in this wavelength regime and with expectations for models of diffuse dust and grain growth in dense clouds.Comment: 8 pages, 4 figures, A&A accepted (Letter), referee forma