Dust source identification using MODIS: A comparison of techniques applied to the Lake Eyre Basin, Australia

The impact of mineral aerosol (dust) in the Earth's system depends on particle characteristics which are initially determined by the terrestrial sources from which the sediments are entrained. Remote sensing is an established method for the detection and mapping of dust events, and has recently been used to identify dust source locations with varying degrees of success. This paper compares and evaluates five principal methods, using MODIS Level 1B and MODIS Level 2 aerosol data, to: (a) differentiate dust (mineral aerosol) from non-dust, and (2) determine the extent to which they enable the source of the dust to be discerned. The five MODIS L1B methods used here are: (1) un-processed false colour composite (FCC), (2) brightness temperature difference, (3) Ackerman's (1997: J.Geophys. Res., 102, 17069-17080) procedure, (4) Miller's (2003:Geophys. Res. Lett. 30, 20, art.no.2071) dust enhancement algorithm and (5) Roskovensky and Liou's (2005: Geophys. Res. Lett. 32, L12809) dust differentiation algorithm; the aerosol product is MODIS Deep Blue (Hsu et al., 2004: IEEE Trans. Geosci. Rem. Sensing, 42, 557-569), which is optimised for use over bright surfaces (i.e. deserts). These are applied to four significant dust events from the Lake Eyre Basin, Australia. OMI AI was also examined for each event to provide an independent assessment of dust presence and plume location. All of the techniques were successful in detecting dust when compared to FCCs, but the most effective technique for source determination varied from event to event depending on factors such as cloud cover, dust plume mineralogy and surface reflectance. Significantly, to optimise dust detection using the MODIS L1B approaches, the recommended dust/non-dust thresholds had to be considerably adjusted on an event by event basis. MODIS L2 aerosol data retrievals were also found to vary in quality significantly between events; being affected in particular by cloud masking difficulties. In general, we find that OMI AI and MODIS AQUA L1B and L2 data are complementary; the former are ideal for initial dust detection, the latter can be used to both identify plumes and sources at high spatial resolution. Overall, approaches using brightness temperature difference (BT10-11) are the most consistently reliable technique for dust source identification in the Lake Eyre Basin. One reason for this is that this enclosed basin contains multiple dust sources with contrasting geochemical signatures. In this instance, BTD data are not affected significantly by perturbations in dust mineralogy. However, the other algorithms tested (including MODIS Deep Blue) were all influenced by ground surface reflectance or dust mineralogy; making it impossible to use one single MODIS L1B or L2 data type for all events (or even for a single multiple-plume event). There is, however, considerable potential to exploit this anomaly, and to use dust detection algorithms to obtain information about dust mineralogy.     

The breakdown into nitric oxide of compounds potentially derived from nitrite in a biological matrix

Summary N-Nitroso compounds can be determined using a chemiluminescence analyzer by means of the nitric oxide liberated as a volatile product of their denitrosation using hydrogen bromide [1, 2]. Much of the nitrite present in or added to a food matrix can be lost even during storage in a refrigerated condition and thus the possibility arises of its conversion into compounds other than nitrosamines and nitrosamides which could also give rise to nitric oxide under, for instance, thermal degradation. Among compounds potentially formed from nitrite that have been studied in relation to their breakdown to nitric oxide have been included an alkyl nitrate, an alkyl nitrite, an amine oxide, an azoxy compound, a nitramine, a nitro guanidine, a nitrolic acid, a nitrone, an oxime, a pseudonitrole, a pseudonitrosite, a thionitrite, a thionitrate as well as C-nitro and C-nitroso compounds. Only in the case of the nitrolic acid and the thionitrate was it likely that interference with the determination of N-nitroso compounds could occur to any considerable extent.

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Abspaltung von NO aus möglichen Folgeprodukten von Nitrit in einer biologischen Matrix

Zusammenfassung N-Nitrosoverbindungen können durch die Chemiluminiscenz-Methode über das Stickoxid bestimmt werden, das durch Denitrosierung mit HBr als flüchtiges Produkt entsteht. Ein großer Teil des Nitrits, das in Lebensmitteln enthalten ist oder zugesetzt wurde kann auch bei Kühllagerung bereits verloren gehen und in andere Produkte als Nitrosamine oder Nitrosamide umgewandelt werden, die bei der thermischen Zersetzung zur Bildung von NO Anlaß geben. Unter den mit Nitrit entstehenden Verbindungen, die zu einer Abspaltung von NO führen könnten, wurden näher untersucht ein Alkylnitrat, ein Alkylnitrit, ein Aminoxyd, eine Azoxy-Verbindung, ein Nitramin, ein Nitroguanidin, eine Nitrolsäure, ein Nitron, ein Oxim, ein Pseudonitrol, ein Pseudonitrosit, ein Thionitrit, sowie C-Nitro- und C-Nitroso-Verbindungen. Nur bei der Nitrolsäure und bei Thionitrat könnte eine Störung der Bestimmung von N-Nitrosoverbindungen über die NO-Abspaltung in beachtlichem Umfang eintreten.

     

Extending the Similarity‐Attraction Effect: The Effects of When‐Similarity in Computer‐Mediated Communication

The feeling of connectedness experienced in computer‐mediated relationships can be explained by the similarity‐attraction effect (SAE). Though SAE is well established in psychology, the effects of some types of similarity have not yet been explored. In 2 studies, we demonstrate similarity‐attraction based on the timing of activities—“when‐similarity.” We describe a novel experimental paradigm for manifesting when‐similarity while controlling for the activities being performed (what‐similarity). Study 1 (N = 24) shows when‐similarity attraction in the evaluation of connectedness with others. Study 2 (N = 42) identifies an interaction between who‐similarity—similarity in personal backgrounds—and when‐similarity. Both studies show that real‐time computer‐mediated interaction can lead to greater feelings of connectedness between people when there is an opportunity to discover when‐similarity.     

Interlingua-based English–Korean Two-way Speech Translation of Doctor–Patient Dialogues with CCLINC

Development of a robust two-way real-time speech translationsystem exposes researchers and system developers to various challenges of machine translation(MT) and spoken language dialogues. The need for communicating in at least two differentlanguages poses problems not present for a monolingual spoken language dialogue system,where no MT engine is embedded within the process flow. Integration of various componentmodules for real-time operation poses challenges not present for text translation. In this paper,we present the CCLINC (Common Coalition Language System at Lincoln Laboratory) English–Koreantwo-way speech translation system prototype trained on doctor–patient dialogues,which integrates various techniques to tackle the challenges of automatic real-time speechtranslation. Key features of the system include (i) language–independent meaning representation which preserves the hierarchicalpredicate–argument structure of an input utterance, providing a powerful mechanism for discourse understanding of utterances originating from different languages,word-sense disambiguation and generation of various word orders of many languages, (ii) adoptionof the DARPA Communicator architecture, a plug-and-play distributed system architecturewhich facilitates integration of component modules and system operation in real time, and (iii)automatic acquisition of grammar rules and lexicons for easy porting of the system to differentlanguages and domains. We describe these features in detail and present experimental results.     

Support for the discharge model of emotion: A reply to Zuckerman.

Responds to criticisms by M. Zuckerman (see record 1984-11616-001) of a study by the present author et al (see record 1983-05644-001) which reported evidence in support of the discharge model of the relation between facial expressivity and physiological reactivity. It is argued that Zuckerman's challenge to the Notarius et al study and conclusions is unfounded for 2 reasons: (a) Zuckerman's critique contains several interpretative errors of the Notarius et al study, and (b) subsequent data analysis, recommended by Zuckerman, overwhelmingly supports the original interpretation of the study. (2 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Annealing and diffusion processes in thin film CdS/Cu2S solar cells

Diffusion of copper during post-fabrication annealing of CdS/Cu₂S thin film solar cells was studied by Auger electron spectroscopy. Depth profiles of the constituent element concentrations indicate that, for samples annealed in air, a deep penetration of copper into the cadmium sulphide layer occurs together with a significant out-diffusion of cadmium. In contrast, the copper penetration which results from vacuum or hydrogen annealing treatment is substantially less and no out-diffusion of cadmium is observed for annealing temperatures up to 400°C.     

Automated patent searching: Preliminary results of USPTO studies

The United States Patent and Trademark Office has begun development of a ‘paperless’ automated system to replace its paper search files. In order to answer several questions related to automated operation, the US Office conducted a number of studies involving commercial patent search systems. The results of these studies are summarized in this paper.     

Anthropocentrism and computers

This paper introduces the multi-dimensional concept of anthropocentrism with respect to computers, the tendency to believe that (1) computers do not possess human physical and psychological capabilities; and (2) it is not acceptable for computers to fill routinized (e.g., auto mechanic), interpretive (e.g., newspaper reporter), and persona) (e.g., baby sitter) roles traditionally held only by people. A mail survey (n = 133) of individuals in Northern California focuses on individual differences rather than differences between technologies. As suggested by the literature on ethnocentrism, experience with other cultures and education are strong predictors of the dimensions of anthropocentrism; surprisingly, experience with computers fails as a predictor.     

External and internal electrostatic potentials of cholinesterase models

The electrostatic potentials for the three-dimensional structures of cholinesterases from various species were calculated, using the Delphi algorithm, on the basis of the Poisson–Boltzmann equation. We used structures for Torpedo californica and mouse acetylcholinesterase, and built homology models of the human, Bungarus fasciatus, and Drosophila melanogaster acetylcholinesterases and human butyrylcholinesterase. All these structures reveal a negative external surface potential, in the area around the entrance to the active-site gorge, that becomes more negative as the rim of the gorge is approached. Moreover, in all cases, the potential becomes increasingly more negative along the central axis running down the gorge, and is largest at the base of the gorge, near the active site. Ten key acidic residues conserved in the sequence alignments of AChE from various species, both in the surface area near the entrance of the active-site gorge and at its base, appear to be primarily responsible for these potentials. The potentials are highly correlated among the structures examined, down to sequence identities as low as 35%. This indicates that they are a conserved property of the cholinesterase family, could serve to attract the positively charged substrate into and down the gorge to the active site, and may play other roles important for cholinesterase function.     

Schedule of Events

In this study, the effect of the user choice on social responses to computer-synthesized speech is investigated. Three previous findings about social responses to computer-synthesized speech (i.e., social identification, proximate source orientation, and similarity attraction) were tested using the choice paradigm. Social identification and proximate source orientation effects were found even when users had chosen a computer voice at their discretion. In addition, the primacy effect in the user choice prevailed: Participants were more likely to select whatever voice that they heard first between two options. The similarity attraction effect, however, was negated by the cognitive dissonance effect after user choices. The robustness of social responses, its implications for human–computer interaction, and the importance of the user choice in voice-interface designs are discussed.