1,405 research outputs found

    Two new advanced forms of spectrometry for space and commercial applications

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    Reagentless ultraviolet absorption spectrometry (UVAS) and Liquid Atomic Emission Spectrometry (LAES) represent new forms of spectrometry with extensive potential in both space and commercial applications. Originally developed under KSC sponsorship for monitoring nutrient solutions for the Controlled Ecological Life Support System (CELSS), both UVAS and LAES have extensive analytical capabilities for both organic and inorganic chemical compounds. Both forms of instrumentation involve the use of remote fiber optic probes and real-time measurements for on-line process monitoring. Commercial applications exist primarily in environmental analysis and for process control in the chemical, pulp and paper, food processing, metal plating, and water/wastewater treatment industries

    Reticulate Reef Patterns - Antecedent Karst Versus Self-Organization

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    Reticulate ridges of reefs and sediment in Holocene lagoons are usually interpreted as an inheritance of antecedent karst topography. Satellite imagery served as a template for integrating plan-view geometry with published data from coring, drilling and seismic surveys to test the antecedent-karst hypothesis. The link between karst morphology and overlying reef patterns can be demonstrated convincingly for a rather limited number of examples, particularly those on a substrate of tower karst with high relief. On very young limestones, doline karst with reticulate patterns develops very slowly because of the high porosity. Moreover, karst control can be ruled out for the significant number of reticulate reefs that are founded on terrigenous sediment or on demonstrably flat pre-Holocene rock surfaces. One likely cause of reticulate patterns is biotic self-organization that has been shown to generate reticulate and labyrinthic patterns of mussel beds on tidal flats and tree cover of arid ecosystems. Another pathway to reticulate reefs may be the colonization of reticulate hydrodynamic bedforms by reef builders. Thus, reticulate patterns of Holocene reef-sediment ridges are highly ambiguous indicators of antecedent karst

    A mobile data acquisition system

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    A mobile data aquisition (MobiDAQ) was developed for the ATLAS central hadronic calorimeter (TileCal). MobiDAQ has been designed in order to test the functionalities of the TileCal front-end electronics and to acquire calibration data before the final back-end electronics were built and tested. MobiDAQ was also used to record the first cosmic ray events acquired by an ATLAS subdetector in the underground experimental area

    Enhanced detection method for corneal protein identification using shotgun proteomics

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    <p>Abstract</p> <p>Background</p> <p>The cornea is a specialized transparent connective tissue responsible for the majority of light refraction and image focus for the retina. There are three main layers of the cornea: the epithelium that is exposed and acts as a protective barrier for the eye, the center stroma consisting of parallel collagen fibrils that refract light, and the endothelium that is responsible for hydration of the cornea from the aqueous humor. Normal cornea is an immunologically privileged tissue devoid of blood vessels, but injury can produce a loss of these conditions causing invasion of other processes that degrade the homeostatic properties resulting in a decrease in the amount of light refracted onto the retina. Determining a measure and drift of phenotypic cornea state from normal to an injured or diseased state requires knowledge of the existing protein signature within the tissue. In the study of corneal proteins, proteomics procedures have typically involved the pulverization of the entire cornea prior to analysis. Separation of the epithelium and endothelium from the core stroma and performing separate shotgun proteomics using liquid chromatography/mass spectrometry results in identification of many more proteins than previously employed methods using complete pulverized cornea.</p> <p>Results</p> <p>Rabbit corneas were purchased, the epithelium and endothelium regions were removed, proteins processed and separately analyzed using liquid chromatography/mass spectrometry. Proteins identified from separate layers were compared against results from complete corneal samples. Protein digests were separated using a six hour liquid chromatographic gradient and ion-trap mass spectrometry used for detection of eluted peptide fractions. The SEQUEST database search results were filtered to allow only proteins with match probabilities of equal or better than 10<sup>-3 </sup>and peptides with a probability of 10<sup>-2 </sup>or less with at least two unique peptides isolated within the run along with default Xcorr values. These parameters resulted in the identification of over 350 proteins, including over 225 new proteins not previously detected in the cornea by mass spectrometry. In addition, corneal layer separation resulted in identification of nearly every protein that was identified in the complete cornea assay. The epithelium and endothelium each revealed many unique proteomes specific to each layer. In the endothelium, the protein olfactomedin-like 3 was identified for the first time in the cornea by this analysis. Olfactomedin-3 is a neuronal expressed protein also known as optimedin that stimulates formation of cell adherent and cell-cell tight junctions and its expression modulates cytoskeleton organization and cell migration. However, the function of this protein in rabbit corneal endothelium is currently unknown.</p> <p>Conclusion</p> <p>This manuscript presents a description of a more comprehensive proteomic profile for mammalian cornea compared to past methods. The use of simple dissection procedures of the tissue and the application of long chromatographic gradients, many more proteins can be identified.</p

    Observations of meteoric material and implications for aerosol nucleation in the winter Arctic lower stratosphere derived from in situ particle measurements

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    Number concentrations of total and non-volatile aerosol particles with size diameters >0.01 μm as well as particle size distributions (0.4–23 μm diameter) were measured in situ in the Arctic lower stratosphere (10–20.5 km altitude). The measurements were obtained during the campaigns European Polar Stratospheric Cloud and Lee Wave Experiment (EUPLEX) and Envisat-Arctic-Validation (EAV). The campaigns were based in Kiruna, Sweden, and took place from January to March 2003. Measurements were conducted onboard the Russian high-altitude research aircraft Geophysica using the low-pressure Condensation Nucleus Counter COPAS (COndensation PArticle Counter System) and a modified FSSP 300 (Forward Scattering Spectrometer Probe). Around 18–20 km altitude typical total particle number concentrations nt range at 10–20 cm−3 (ambient conditions). Correlations with the trace gases nitrous oxide (N2O) and trichlorofluoromethane (CFC-11) are discussed. Inside the polar vortex the total number of particles >0.01 μm increases with potential temperature while N2O is decreasing which indicates a source of particles in the above polar stratosphere or mesosphere. A separate channel of the COPAS instrument measures the fraction of aerosol particles non-volatile at 250°C. Inside the polar vortex a much higher fraction of particles contained non-volatile residues than outside the vortex (~67% inside vortex, ~24% outside vortex). This is most likely due to a strongly increased fraction of meteoric material in the particles which is transported downward from the mesosphere inside the polar vortex. The high fraction of non-volatile residual particles gives therefore experimental evidence for downward transport of mesospheric air inside the polar vortex. It is also shown that the fraction of non-volatile residual particles serves directly as a suitable experimental vortex tracer. Nanometer-sized meteoric smoke particles may also serve as nuclei for the condensation of gaseous sulfuric acid and water in the polar vortex and these additional particles may be responsible for the increase in the observed particle concentration at low N2O. The number concentrations of particles >0.4 μm measured with the FSSP decrease markedly inside the polar vortex with increasing potential temperature, also a consequence of subsidence of air from higher altitudes inside the vortex. Another focus of the analysis was put on the particle measurements in the lowermost stratosphere. For the total particle density relatively high number concentrations of several hundred particles per cm3 at altitudes below ~14 km were observed in several flights. To investigate the origin of these high number concentrations we conducted air mass trajectory calculations and compared the particle measurements with other trace gas observations. The high number concentrations of total particles in the lowermost stratosphere are probably caused by transport of originally tropospheric air from lower latitudes and are potentially influenced by recent particle nucleation

    HAIRY-like Transcription Factors and the Evolution of the Nematode Vulva Equivalence Group

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    SummaryBackgroundNematode vulva formation provides a paradigm to study the evolution of pattern formation and cell-fate specification. The Caenorhabditis elegans vulva is generated from three of six equipotent cells that form the so-called vulva equivalence group. During evolution, the size of the vulva equivalence group has changed: Panagrellus redivivus has eight, C. elegans six, and Pristionchus pacificus only three cells that are competent to form vulval tissue. In P. pacificus, programmed cell death of individual vulval precursor cells alters the size of the vulva equivalence group.ResultsWe have identified the genes controlling this cell-death event and the molecular mechanism of the reduction of the vulva equivalence group. Mutations in Ppa-hairy, a gene that is unknown from C. elegans, result in the survival of two precursor cells, which expands the vulva equivalence group. Mutations in Ppa-groucho cause a similar phenotype. Ppa-HAIRY and Ppa-GROUCHO form a molecular module that represses the Hox gene Ppa-lin-39 and thereby reduces the size of the vulva equivalence group. The C. elegans genome does not encode a similar hairy-like gene, and no typical HAIRY/GROUCHO module exists.ConclusionsWe conclude that the vulva equivalence group in Pristionchus is patterned by a HAIRY/GROUCHO module, which is absent in Caenorhabditis. Thus, changes in the number, structure, and function of nematode hairy-like transcription factors are involved in the evolutionary alteration of this equivalence group

    Synchroneity of major late Neogene sea level fluctuations and paleoceanographically controlled changes as recorded by two carbonate platforms

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    Shallow-water carbonate systems are reliable recorders of sea level fluctuations and changes in ambient seawater conditions. Drilling results from Ocean Drilling Program (ODP) Legs 133 and 166 indicate that the timing of late Neogene sedimentary breaks triggered by sea level lowerings is synchronous in the sedimentary successions of the Queensland Plateau and the Great Bahama Bank. This synchrony indicates that these sea level changes were eustatic in origin. The carbonate platforms were also affected by contemporary, paleoceanographically controlled fluctuations in carbonate production. Paleoceanographic changes are recorded at 10.7, 3.6, and 1.7–2.0 Ma. At the Queensland Plateau, sea surface temperature shifts are documented by shifts from tropical to temperate carbonates (10.7 Ma) and vice versa (3.6 Ma); the modern tropical platform was established at 2.0–1.8 Ma. At Great Bahama Bank, changes were registered in compositional variations of platform-derived sediment, such as major occurrence of peloids (3.6 Ma) and higher rates of neritic carbonate input (1.7 Ma). The synchroneity of these changes attests to the far-field effects of modifications in the oceanographic circulation on shallow-water, low-latitude carbonate production

    Modeling the evolution of aerosol particles in a ship plume using PartMC-MOSAIC

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    This study investigates the evolution of ship-emitted aerosol particles using the stochastic particle-resolved model PartMC-MOSAIC (Particle Monte Carlo model-Model for Simulating Aerosol Interactions and Chemistry). Comparisons of our results with observations from the QUANTIFY (Quantifying the Climate Impact of Global and European Transport Systems) study in 2007 in the English Channel and the Gulf of Biscay showed that the model was able to reproduce the observed evolution of total number concentration and the vanishing of the nucleation mode consisting of sulfate particles. Further process analysis revealed that during the first hour after emission, dilution reduced the total number concentration by four orders of magnitude, while coagulation reduced it by an additional order of magnitude. Neglecting coagulation resulted in an overprediction of more than one order of magnitude in the number concentration of particles smaller than 40 nm at a plume age of 100 s. Coagulation also significantly altered the mixing state of the particles, leading to a continuum of internal mixtures of sulfate and black carbon. The impact on cloud condensation nuclei (CCN) concentrations depended on the supersaturation threshold <i>S</i> at which CCN activity was evaluated. For the base case conditions, characterized by a low formation rate of secondary aerosol species, neglecting coagulation, but simulating condensation, led to an underestimation of CCN concentrations of about 37% for <i>S</i> = 0.3% at the end of the 14-h simulation. In contrast, for supersaturations higher than 0.7%, neglecting coagulation resulted in an overestimation of CCN concentration, about 75% for <i>S</i> = 1%. For <i>S</i> lower than 0.2% the differences between simulations including coagulation and neglecting coagulation were negligible. Neglecting condensation, but simulating coagulation did not impact the CCN concentrations below 0.2% and resulted in an underestimation of CCN concentrations for larger supersaturations, e.g., 18% for <i>S</i> = 0.6%. We also explored the role of nucleation for the CCN concentrations in the ship plume. For the base case the impact of nucleation on CCN concentrations was limited, but for a sensitivity case with higher formation rates of secondary aerosol over several hours, the CCN concentrations increased by an order of magnitude for supersaturation thresholds above 0.3%

    Technical Note: Characterisation of a DUALER instrument for the airborne measurement of peroxy radicals during AMMA 2006

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    A DUALER (dual-channel airborne peroxy radical chemical amplifier) instrument has been developed and optimised for the airborne measurement of the total sum of peroxy radicals during the AMMA (African Monsoon Multidisciplinary Analyses) measurement campaign which took place in Burkina Faso in August 2006. The innovative feature of the instrument is that both reactors are sampling simultaneously from a common pre-reactor nozzle while the whole system is kept at a constant pressure to ensure more signal stability and accuracy. &lt;br&gt;&lt;br&gt; Laboratory experiments were conducted to characterise the stability of the NO&lt;sub&gt;2&lt;/sub&gt; detector signal and the chain length with the pressure. The results show that airborne measurements using chemical amplification require constant pressure at the luminol detector. Wall losses of main peroxy radicals HO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt; were investigated. The chain length was experimentally determined for different ambient mixtures and compared with simulations performed by a chemical box model. &lt;br&gt;&lt;br&gt; The DUALER instrument was successfully mounted within the German DLR-Falcon. The analysis of AMMA data utilises a validation procedure based on the O&lt;sub&gt;3&lt;/sub&gt; mixing ratios simultaneously measured onboard. The validation and analysis procedure is illustrated by means of the data measured during the AMMA campaign. The detection limit and the accuracy of the ambient measurements are also discussed

    Archetypal Reading of Fairytales

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    Tema je rada arhetipsko tumačenje bajke. Polazne pretpostavke istraživanja bile su moguće definicije bajki unutar kojih se pokušalo smjestiti jungovsku psihoanalitičku teoriju o arhetipovima na primjerima različitih likova svjetskih, europskih, kao i hrvatskih bajki. Ponajprije se bajka definira kao vrsta, a zatim je definiran pojam arhetipa, koji pripada psihoanalizi Carla Gustava Junga. Prema Jungovoj teoriji, arhetipovi su modeli osobnosti, „praslike“ i dio kolektivno nesvjesnoga te je u njima moguće pronaći simboliku za mnoge modele ponašanja svih ljudi. Cilj je rada proučiti psihoanalitičke stavove Carla Gustava Junga s obzirom na tumačenje arhetipova te primijeniti ta učenja na bajku i njezine likove. Predstavljeni su narativni čimbenici bajke te kako se njihova uloga uklapa u koncept arhetipskog čitanja, a poseban je naglasak stavljen na arhetipove Jastva, Anime, Animusa, Sjene i Persone, na temelju čijih su karakteristika i simbolike razvrstani mnogi likovi iz poznatih europskih i hrvatskih bajki. Svaki je arhetip predstavljen s psihoanalitičke strane, koristeći kao glavnu teorijsku literarnu jedinicu knjigu Jolande Jacobi Psihologija C.G.Junga, a u interpretaciji arhetipskih likova u bajkama knjigu Marie-Louise von Franz Interpretacija bajki
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