Intercalibration of SUMER and CDS on SOHO. III. SUMER and CDS-GIS. Solar and Heliospheric Observatory

Simultaneous observation of the same solar sources with different instruments is one way to test prelaunch radiometric calibrations and to detect changes in responsivity with time of extreme-ultraviolet instruments in space. Here we present the results of intercalibration of the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrometer (detectors A and B) and the GIS (Grazing Incidence Spectrometer), one of two spectrometers that compose the CDS (Coronal Diagnostic Spectrometer) on the Solar and Heliospheric Observatory (SOHO). The two instruments observed simultaneously radiances of emission lines at or near the center of the solar disk. The emission line chosen for intercomparison was Ne VIII at 770 A. However, such an intercomparison of the SUMER and CDS-GIS measurements means comparing two data sets with large differences in resolution and field of view. The latter difference, especially, introduces differences in the measured intensities caused by the solar variability that is relatively strong in the 770-A line. Using a statistical approach to overcome this problem, we found that the ratio of the GIS to the SUMER average radiances amounted to 2.6 +/- 0.9 before the SOHO's loss of attitude and to 2.1 +/- 0.7 afterward. These findings confirm earlier estimates of the GIS's responsivity being too low, and an update of the GIS calibration is recommended. Despite the large differences in resolution and field of view of the two instruments, the shapes of their normalized and rescaled histograms of the radiances agree well and therefore represent characteristic features of the Ne VIII line.     

Intercalibration of SUMER and CDS on SOHO. II. SUMER Detectors A and B and CDS NIS

Results of an intercalibration between the extreme-ultraviolet spectrometers Coronal Diagnostic Spectrometer (CDS) and Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on board the Solar and Heliospheric Observatory (SOHO) are reported. The results of the joint observing program Intercal_01 are described, and intercalibration results up to July 2000 of both SUMER detectors A and B and of the CDS Normal Incidence Spectrometer (NIS) are presented. The instruments simultaneously observed radiance of emission lines at the center of the Sun, and three lines have been chosen for intercomparison: He i 584 A, Mg x 609 A, and Mg x 624 A. Initially the same area was observed by both instruments, but, after restrictions were imposed by the scanning mechanism of SUMER in November 1996, the instruments viewed areas of different sizes. Nevertheless, the temporal correlation between the two instruments remained good through June 1998, when contact with the SOHO spacecraft was lost. Until then the CDS instrument measured (33 ? 5)% and (38 ? 7)% (?1varsigma) higher intensity than SUMER in the He i 584-A line on average for detectors A and B, respectively. Data from SUMER detector B agreed well for Mg x 609 A and Mg x 624 A with the CDS intensities, showing offsets of (2 ? 10)% and (9 ? 15)%, much less than the data of detector A with offsets of (7 ? 8)% and (16 ? 7)% for the two lines, respectively, relative to CDS. Finally, the intercalibration measurements after the loss and recovery of the SOHO spacecraft are analyzed. The data for observations from November 1998 to July 2000 are compared, and it is shown that, although the responses of the instruments have changed, the CDS and the SUMER still perform well, and their temporal correlation is good.     

Toxicity of the combustion and decomposition products of polyurethanes

The acute toxicity by inhalation of polyurethane combustion and decomposition products was investigated by means of animal experiments. The results demonstrated that previous regulative and normative approaches which are based on the chemical nature of the materials tested and the analytically determined concentration data for major fire gas components are inconsistent with the research findings set out in TR 9122 of ISO TC92 SC3. The animal experiments, which complied with the test and assessment criteria put forward by the experts of ISO TC92 SC3 ‘Toxic Hazards in Fire’, provided convincing evidence that the overall toxic potency of the decomposition products released by polyurethane foam and PU coatings under comparable fire conditions was the same as for wood or wool. It was found that the acute toxic hazard potential of combustion gases is determined by the concentration of toxic components in the fire effluents (which in turn depends on the quantity of material burned in unit time) and by local conditions. This means that all parameters capable of affecting the combustion process are critical.     

Structural studies on Ca3Al4MgO10 (C3A2M)—A ternary phase in the system CaO–Al2O3–MgO

In a sequence of temperature-dependent solid-state reactions in the system CaO–Al₂O₃–MgO the formation of the ternary phase Ca₃Al₄MgO₁₀ or C₃A₂M has been studied. Whereas the compound could not be prepared at 1200°C, a yield of 85 wt.-% of Ca₃Al₄MgO₁₀ was obtained at 1320°C (incongruent melting point: 1330°C). Powder diffraction data compare well with results of previous investigations from the 1960s. Single crystals of Ca₃Al₄MgO₁₀ could be retrieved from the sinter-pellets. Basic crystallographic data are as follows: orthorhombic symmetry, space group Pbcm, a = 5.14073(8), b = 16.7576(2), c = 10.70977(16) Å, V = 922.61(2) ų, Z = 4. Using synchrotron diffraction data it was possible to solve the crystal structure. Least-squares refinements resulted in a residual of R(|F|) = 0.021 for 1000 independent observed reflections with I > 2σ(I) and 97 parameters. The structure contains [TO₄]-tetrahedra (T=Al,Mg) forming a three-dimensional (3-D) framework whose topological characteristics have been determined. Al-Mg distributions on the different T-sites have been studied. The calcium cations are located in voids of the network. More than 50 years after its first observation our investigation clarifies the crystal structure of a compound belonging to a system that is of relevance for several fields of materials science.     

Nenek: a cloud-based collaboration platform for the management of Amerindian language resources

This article presents Nenek: A cloud-based collaboration platform for language documentation of underresourced languages. Nenek is based on a crowdsourcing scheme that supports native speakers, indigenous associations, government agencies and researchers in the creation of virtual communities of minority language speakers on the Internet. Nenek includes a set of web tools that enables users to work collaboratively on language documentation tasks, build lexicographic assets and produce new language resources. This platform includes a three-stage management model to control the acquisition of existent language resources, the manufacturing of new resources, as well as their distribution within the virtual community and to the general public. In the acquisition stage, existent language resources are either automatically extracted from the web by a crawler or received through donations from users who participate in a monolingual social network. In the manufacturing stage, lexicographic and collaborative tools enable users to build new resources while the acquired and manufactured resources are published in the diffusion stage, either within the virtual community or publicly. We present a life cycle mapping scheme that registers the transformations of the language resources at each of the three stages of language resource management. This scheme also traces the utilization and diffusion of each resource produced by the virtual community. The paper includes a case study in which we present the use of the Nenek platform in a language documentation project of a Mayan language spoken in Mexico's Gulf coast region called Huastec. This case study reveals Nenek's efficiency in terms of acquisition, annotation, manufacturing and diffusion of language resources; it also discusses the participation of the members of the virtual community.     

Intercalibration of SUMER and CDS on SOHO. I. SUMER detector A and CDS NIS

The results of an intercalibration between the extreme ultraviolet spectrometers Coronal Diagnostic Spectrometer (CDS) and Solar Ultraviolet Measurements of Emitted Radiation (SUMER) onboard the Solar and Heliospheric Observatory (SOHO) are presented. During the joint observing program Intercal_01, CDS and SUMER were pointed at the same locations in quiet Sun areas and observed in the same wavelength bands located around the spectral lines He i 584 A, Mg x 609 A, and Mg x 624 A. The data sets analyzed here consist of raster images recorded by the CDS normal-incidence spectrometer and SUMER detector A and span the time from March 1996 to August 1996. Effects of the different spatial and spectral resolutions of both instruments have been investigated and taken into account in the analysis. We find that CDS measures generally a 30% higher intensity than SUMER in the He i 584-A line, while it measures 9% and 17% higher intensities in Mg x 609 A and Mg x 624 A, respectively. Both instruments show very good temporal correlation and stability, indicating that solar variations dominate over changes in instrumental sensitivity. Our analysis also provides in-flight estimates of the CDS spatial point-spread functions.     

Persistent organic pollutants and mercury in dead and dying glaucous gulls (Larus hyperboreus) at Bjørnøya (Svalbard)

Dead and dying glaucous gulls (Larus hyperboreus) were collected on Bjørnøya in the Barents Sea in 2003, 2004 and 2005. Autopsies of the seabirds only explained a clear cause of death for three (14%) of the 21 birds. A total of 71% of the birds were emaciated. Liver and brain samples were analysed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ether (PBDEs), hexabromocyclododecanes (HBCDs) and mercury (Hg). High levels of ΣOCPs, ΣPCBs, ΣPBDEs and α-HBCD were found in liver and brain. Compared to the dead and dying glaucous gulls found 1989, the congeners' composition tended to change toward more persistent compounds in the 2003–2005 samples. The brain levels of OCPs and PCBs did not differ between 1989 and 2003–2005, while the liver levels were significantly lower. The brain/liver ratio for PCB and PBDE significantly decreased with halogenations of the molecule, indicating a clear discrimination of highly halogenated PCBs and PBDEs entering the brain. There was further a clear negative correlation between contaminant concentrations and body condition. The brain levels were not as high as earlier published lethal levels of p,p′-DDE or PCB. However, more recent studies reported a range of sub-lethal OCP- and PCB-related effects in randomly sampled glaucous gulls. An additional elevation of pollutants due to emaciation may increase the stress of the already affected birds. The high brain levels of OCP, PCB and PBDE of present study might therefore have contributed to the death of weakened individuals of glaucous gull.     

Predictive elution window stretching and shifting as a generic search strategy for automated method development for liquid chromatography

We report on the possibilities of a new method development (MD) algorithm that searches the chromatographic parameter space by systematically shifting and stretching the elution window over different parts of the time-axis. In this way, the search automatically focuses on the most promising areas of the solution space. Since only the retention properties of the first and last eluting compounds of the sample need to be (approximately) known, the algorithm can be directly applied to samples with unknown composition, and the proposed solutions are not sensitive to any modeling errors. The search efficiency of the algorithm has been evaluated on an extensive set of random-generated in silico samples covering a broad range of different retention properties. Compared to a pure grid-based search, the algorithm could reduce the number of missed components by 50% and more. The algorithm has also been applied to solve three different real-world separation problems from the pharmaceutical industry. All problems could be successfully solved in a very short time (order of 12 h of instrument time).     

Toxicologic evaluation of pyrethroids in indoor air: demonstrated with the example of cyfluthrin and permethrin

Pyrethroids have varying activities depending on vehicle or route of administration (oral, dermal, inhalational). Specific features like the sensory irritation potential of the alpha-cyano-pyrethroids on the respiratory tract can only be quantified adequately by inhalation testing. Thus equitoxic dosages can vary between inhalative and oral application, especially for alpha-cyano-pyrethrolds. The no-effect values for chronic exposures derived for permethrin (type I pyrethroid) and cyfluthrin (type II pyrethroid) show clearly, that each pyrethroid has to be considered as an individual substance toxicologically, and that any extrapolation from the oral to the inhalative route should only be done after a thorough assessment of the specific toxicological profile. The study of simulated pest control measures on carpets pretreated with permethrin showed, that no significant enrichment of permethrin in total dust could be seen from a carpet additionally treated with pyrethroids. The missing correlation between absolute (mg pyrethroid/m3 air) and relative (mg pyrethroid/kg dust) concentrations in air-borne dust as well as the low degree of translocation of pyrethroids from carpets (only about 0.044% x m(-2) x h(-1) of the cyfluthrin applied to the carpet can be regarded as possibly respirable) prove, that analyses of pyrethroids in household sedimented dust ("vacuum cleaner bag analyses") without knowing the absolute surface concentration and respective air concentrations are of little value for risk assessment. The data allow the conclusion, that a scientific assessment of health risks is only possible based on absolute concentrations of pyrethroids in indoor air.     

Nitrogen form affects yield and taste of tomatoes

Different nitrogen forms in organic or mineral fertilizers affect yield, quality and taste of tomatoes. Tomato plants were grown in a greenhouse for 10 weeks and fertilized with two different organic fertilizers (manure or grass and clover mulch) or with three different mineral nutrient solutions (NO₃^?:NH₄⁺) ratios 4:1 or 1:4). In an attempt to mimic the nutrient supply of the organic production systems, mineral fertilizers with ammonium as the dominating N‐source were combined with two chloride levels. Total nitrogen supply was 650 mg N plant^?1 week^?1 in all treatments. There was no difference in the yield of red tomatoes between the treatments (mean 1.95 kg FW plant^?1). However, the yield of green tomatoes at the final harvest was significantly higher in the mineral nutrient treatments (mean 1.37 kg FW plant^?1) compared with the organic treatments (mean 0.88 kg FW plant^?1). Plant biomass was higher for the mineral nutrient treatments (mean 1.05 kg FW plant^?1) compared with the organic treatments (0.89 kg and 0.72 kg FW plant^?1 in the manure and the grass and clover mulch treatments, respectively). Significantly higher scores were achieved for sweetness, acidity, flavour and acceptance for the tomatoes grown with the organic or the ammonium‐dominated treatments compared with the tomatoes grown with the nitrate dominated nutrient solution. It is suggested that ammonium is an equivalent nitrogen source for tomato plants compared with nitrate and that, when tomato plants are supplied with reduced nitrogen forms such as ammonium or organic nitrogen, an improved tomato fruit taste can be observed. Copyright © 2005 Society of Chemical Industry