| 1. |
- Kratz, David P., et al.
(författare)
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An inter-comparison of far-infrared line-by-line radiative transfer models
- 2005
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier BV. - 0022-4073 .- 1879-1352. ; 90:3-4, s. 323-341
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Tidskriftsartikel (refereegranskat)abstract
- A considerable fraction (>40%) of the outgoing longwave radiation escapes from the Earth's atmosphere-surface system within a region of the spectrum known as the far-infrared (wave-numbers less than ). Dominated by the line and continuum spectral features of the pure rotation band of water vapor, the far-infrared has a strong influence upon the radiative balance of the troposphere, and hence upon the climate of the Earth. Despite the importance of the far-infrared contribution, however, very few spectrally resolved observations have been made of the atmosphere for wave-numbers less than . The National Aeronautics and Space Administration (NASA), under its Instrument Incubator Program (IIP), is currently developing technology that will enable routine, space-based spectral measurements of the far-infrared. As part of NASA's IIP, the Far-Infrared Spectroscopy of the Troposphere (FIRST) project is developing an instrument that will have the capability of measuring the spectrum over the range from 100 to at a resolution of . To properly analyze the data from the FIRST instrument, accurate radiative transfer models will be required. Unlike the mid-infrared, however, no inter-comparison of codes has been performed for the far-infrared. Thus, in parallel with the development of the FIRST instrument, an investigation has been undertaken to inter-compare radiative transfer models for potential use in the analysis of far-infrared measurements. The initial phase of this investigation has focused upon the inter-comparison of six distinct line-by-line models. The results from this study have demonstrated remarkably good agreement among the models, with differences being of order 0.5%, thereby providing a high measure of confidence in our ability to accurately compute spectral radiances in the far-infrared.
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| 2. |
- Mlynczak, Martin G., et al.
(författare)
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Energy transport in the thermosphere during the solar storms of April 2002
- 2005
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Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 110:A12
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Tidskriftsartikel (refereegranskat)abstract
- The dramatic solar storm events of April 2002 deposited a large amount of energy into the Earth's upper atmosphere, substantially altering the thermal structure, the chemical composition, the dynamics, and the radiative environment. We examine the flow of energy within the thermosphere during this storm period from the perspective of infrared radiation transport and heat conduction. Observations from the SABER instrument on the TIMED satellite are coupled with computations based on the ASPEN thermospheric general circulation model to assess the energy flow. The dominant radiative response is associated with dramatically enhanced infrared emission from nitric oxide at 5.3 μm from which a total of ∼7.7 × 1023 ergs of energy are radiated during the storm. Energy loss rates due to NO emission exceed 2200 Kelvin per day. In contrast, energy loss from carbon dioxide emission at 15 μm is only ∼2.3% that of nitric oxide. Atomic oxygen emission at 63 μm is essentially constant during the storm. Energy loss from molecular heat conduction may be as large as 3.8% of the NO emission. These results confirm the “natural thermostat” effect of nitric oxide emission as the primary mechanism by which storm energy is lost from the thermosphere below 210 km.
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| 3. |
- Mlynczak, Martin G., et al.
(författare)
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Evidence for a solar cycle influence on the infrared energy budget and radiative cooling of the thermosphere
- 2007
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Ingår i: Journal of Geophysical Research - Space Physics. - 2169-9380 .- 2169-9402. ; 112:A12
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Tidskriftsartikel (refereegranskat)abstract
- We present direct observational evidence for solar cycle influence on the infrared energy budget and radiative cooling of the thermosphere. By analyzing nearly five years of data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, we show that the annual mean infrared power radiated by the nitric oxide (NO) molecule at 5.3 μm has decreased by a factor of 2.9. This decrease is correlated (r = 0.96) with the decrease in the annual mean F10.7 solar index. Despite the sharp decrease in radiated power (which is equivalent to a decrease in the vertical integrated radiative cooling rate), the variability of the power as given in the standard deviation of the annual means remains approximately constant. A simple relationship is shown to exist between the infrared power radiated by NO and the F10.7 index, thus providing a fundamental relationship between solar activity and the thermospheric cooling rate for use in thermospheric models. The change in NO radiated power is also consistent with changes in absorbed ultraviolet radiation over the same time period. Computations of radiated power using an empirical model show much less variability than observed by SABER.
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| 4. |
- Mlynczak, Martin G., et al.
(författare)
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Solar-terrestrial coupling evidenced by periodic behavior in geomagnetic indexes and the infrared energy budget of the thermosphere
- 2008
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 35:5
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Tidskriftsartikel (refereegranskat)abstract
- We examine time series of the daily global power (W) radiated by carbon dioxide (at 15 μm) and by nitric oxide (at 5.3 μm) from the Earth's thermosphere between 100 km and 200 km altitude. Also examined is a time series of the daily absorbed solar ultraviolet power in the same altitude region in the wavelength span 0 to 175 run. The infrared data are derived from the SABER instrument and the solar data are derived from the SEE instrument, both on the NASA TIMED satellite. The time series cover nearly 5 years from 2002 through 2006. The infrared and solar time series exhibit a decrease in radiated and absorbed power consistent with the declining phase of the current 11-year solar cycle. The infrared time series also exhibits high frequency variations that are not evident in the solar power time series. Spectral analysis shows a statistically significant 9-day periodicity in the infrared data but not in the solar data. A very strong 9-day periodicity is also found to exist in the time series of daily Ap and Kp geomagnetic indexes. These 9-day periodicities are linked to the recurrence of coronal holes on the Sun. These results demonstrate a direct coupling between the upper atmosphere of the Sun and the infrared energy budget of the thermosphere. Copyright 2008 by the American Geophysical Union.
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| 5. |
- Mlynczak, Martin G., et al.
(författare)
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Sounding of the Atmosphere using Broadband Emission Radiometry observations of daytime mesospheric O2(1Δ) 1.27 μm emission and derivation of ozone, atomic oxygen, and solar and chemical energy deposition rates
- 2007
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Ingår i: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 112:D15
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Tidskriftsartikel (refereegranskat)abstract
- We report observations of the daytime O2(1Δ) airglow emission at 1.27 μm recorded by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite. The measured limb radiances are inverted to yield vertical profiles of the volume emission rate of energy from the O2 molecule. From these emission rates we subsequently derive the mesospheric ozone concentrations using a nonlocal thermodynamic equilibrium (non-LTE) radiative and kinetic model. Rates of energy deposition due to absorption of ultraviolet radiation in the Hartley band of ozone are also derived, independent of knowledge of the ozone abundance and solar irradiances. Atomic oxygen concentrations are obtained from the ozone abundance using photochemical steady state assumptions. Rates of energy deposition due to exothermic chemical reactions are also derived. The data products illustrated here are from a test day (4 July 2002) of SABER Version 1.07 data which are now becoming publicly available. This test day illustrates the high quality of the SABER O2(1Δ) airglow and ozone data and the variety of fundamental science questions to which they can be applied.
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| 6. |
- Nene, Vishvanath, et al.
(författare)
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Genome sequence of Aedes aegypti, a major arbovirus vector.
- 2007
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 316:5832, s. 1718-23
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Tidskriftsartikel (refereegranskat)abstract
- We present a draft sequence of the genome of Aedes aegypti, the primary vector for yellow fever and dengue fever, which at approximately 1376 million base pairs is about 5 times the size of the genome of the malaria vector Anopheles gambiae. Nearly 50% of the Ae. aegypti genome consists of transposable elements. These contribute to a factor of approximately 4 to 6 increase in average gene length and in sizes of intergenic regions relative to An. gambiae and Drosophila melanogaster. Nonetheless, chromosomal synteny is generally maintained among all three insects, although conservation of orthologous gene order is higher (by a factor of approximately 2) between the mosquito species than between either of them and the fruit fly. An increase in genes encoding odorant binding, cytochrome P450, and cuticle domains relative to An. gambiae suggests that members of these protein families underpin some of the biological differences between the two mosquito species.
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| 7. |
- Siskind, David E., et al.
(författare)
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Decreases in atomic hydrogen over the summer pole : Evidence for dehydration from polar mesospheric clouds?
- 2008
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 35:13
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Tidskriftsartikel (refereegranskat)abstract
- Observations from the Sounding of the Atmosphere with Broadband Emission Radiometry (SABER) instrument on the NASA/Thermospheric Ionosphere Mesosphere Energetics and Dynamics satellite show a surprising decrease in the inferred atomic hydrogen (H) over the polar regions in the lowermost thermosphere during the summer. This contrasts with predictions by global models that H should peak in this region at this time. We suggest the decrease is a consequence of the sequestering of the water vapor by the formation of polar mesospheric clouds (PMCs) that redistributes the H2O thus reducing the chemical source of H. This decrease is more pronounced in the Northern rather than the Southern summer which is roughly consistent with the known morphology of PMCs. A model calculation which includes a PMC parameterization gives good qualitative agreement with the data suggesting that this process should be considered in global models of the coupling between the middle and upper atmosphere. Copyright 2008 by the American Geophysical Union.
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| 8. |
- Smith, Anne K., et al.
(författare)
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Satellite observations of high nighttime ozone at the equatorial mesopause
- 2008
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 113:17
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Tidskriftsartikel (refereegranskat)abstract
- Measurements by the Sounding of the Atmosphere using Broadband Emission Radiometry instrument enable the characterization of the seasonal variation of ozone and temperature in the upper mesosphere. These are the first global measurements that resolve both the structure of the secondary ozone maximum at night and the temperature over all seasons of the year. The average nighttime mixing ratios at the altitude of the maximum vary with latitude and season. Analysis shows that the highest mixing ratios are clustered near the equator during equinoxes. The high ozone mixing ratios are observed in exactly the place and time at which the diurnal tide is largest. The diurnal tidal phase is such that coldest temperatures at 95 km occur near midnight. The high ozone is coincident with regions that have both low temperature and low amounts of atomic hydrogen. We focus particularly on ozone mixing ratios in the range of 18-50 ppmv; these occur intermittently in the equinoctial tropics on days when the night temperature is particularly cold. The occurrence of ozone maxima over 20 ppmv was unexpected but is shown in this paper to be consistent with theory and is a result of large-amplitude diurnal tides. The same seasonal and latitudinal characteristics are seen in ozone density measured by Global Ozone Monitoring by Occultation of Stars. Copyright 2008 by the American Geophysical Union.
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| 9. |
- Abelson, Anna-Karin, et al.
(författare)
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STAT4 Associates with SLE through two independent effects that correlate with gene expression and act additively with IRF5 to increase risk
- 2009
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 68:11, s. 1746-1753
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To confirm and define the genetic association of STAT4 and systemic lupus erythematosus, investigate the possibility of correlations with differential splicing and/or expression levels, and genetic interaction with IRF5. METHODS: 30 tag SNPs were genotyped in an independent set of Spanish cases and controls. SNPs surviving correction for multiple tests were genotyped in 5 new sets of cases and controls for replication. STAT4 cDNA was analyzed by 5'-RACE PCR and sequencing. Expression levels were measured by quantitative PCR. RESULTS: In the fine-mapping, four SNPs were significant after correction for multiple testing, with rs3821236 and rs3024866 as the strongest signals, followed by the previously associated rs7574865, and by rs1467199. Association was replicated in all cohorts. After conditional regression analyses, two major independent signals represented by SNPs rs3821236 and rs7574865, remained significant across the sets. These SNPs belong to separate haplotype blocks. High levels of STAT4 expression correlated with SNPs rs3821236, rs3024866 (both in the same haplotype block) and rs7574865 but not with other SNPs. We also detected transcription of alternative tissue-specific exons 1, indicating presence of tissue-specific promoters of potential importance in the expression of STAT4. No interaction with associated SNPs of IRF5 was observed using regression analysis. CONCLUSIONS: These data confirm STAT4 as a susceptibility gene for SLE and suggest the presence of at least two functional variants affecting levels of STAT4. Our results also indicate that both genes STAT4 and IRF5 act additively to increase risk for SLE.
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| 10. |
- Bergblomma, Marcus, et al.
(författare)
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Wireless ECG network
- 2009
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Ingår i: WORLD CONGRESS ON MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING, VOL 25, PT 5. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783642039034 ; , s. 244-247
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Konferensbidrag (refereegranskat)abstract
- This paper presents a time synchronized wireless ECG sensor network with reliable data communication. Wireless ECG systems are a popular research area where several research groups have presented point-to-point solutions. Alongside the wireless ECG research, the wireless sensor network research has created an increasing interest for secure, low power and predictable network applications. Combining these research areas is a natural step for the evolution of secure wireless monitoring of physiological parameters. In this study the Bluetooth radio standard has been chosen for its versatility. This paper focuses on both the hardware and the software development for a functional multihop ECG network using Bluetooth. The presented wireless ECG network is reliable up to link loss and is easily configured to send more or different types of signals. The system has been tested and verified for secure multihop communication.
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