Moderate Bands Research Articles

VIIRS-derived ocean color product using the imaging bands

A technique and implementation for deriving ocean color product using the imaging band (I-band) measurements from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) have been developed. The three VIIRS-SNPP image bands (638, 862, and 1600nm) with spatial resolution of 375m are much better than the VIIRS moderate (M) resolution bands of 750m, which have been used for routinely producing VIIRS global ocean color products. In particular, the high spatial resolution of VIIRS-derived normalized water-leaving radiance at the wavelength of 638nm (I1 band) nLw(638) can provide useful information about water optical, biological, and biogeochemical properties over turbid coastal and inland waters. In addition, VIIRS-derived nLw(638) data provide an important spectral point and coverage along with nLw(λ) from the seven VIIRS M-bands at wavelengths of 410, 443, 486, 551, 671, 745, and 862nm, particularly over turbid coastal and inland waters. In this paper, we describe our effort to develop a technique for deriving VIIRS nLw(λ) spectra for both M-bands and I-bands using the Multi-Sensor Level-1 to Level-2 (MSL12) ocean color data processing system. Some examples of VIIRS-derived nLw(638) are provided and discussed, showing the usefulness of this added capability for providing water properties over global turbid coastal and inland waters. Therefore, MSL12 is now capable of routinely and efficiently producing VIIRS nLw(638) for both spatial resolutions of 375 and 750m, along with nLw(λ) spectra at VIIRS M1–M7 with the spatial resolution of 750m.

On-Orbit Line Spread Function Estimation of the SNPP VIIRS Imaging System From Lake Pontchartrain Causeway Bridge Images

The visible infrared imaging radiometer suite (VIIRS) instrument was launched on October 28, 2011 onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite. The VIIRS instrument is a whiskbroom system with 22 spectral and thermal bands split between 16 moderate resolution bands (M-bands), five imagery resolution bands (I-bands), and a day–night band. In this study, we estimate the along-scan line spread function (LSF) of the I-bands and M-bands based on measurements performed on images of the Lake Pontchartrain Causeway Bridge. In doing so, we develop a model for the LSF that closely matches the prelaunch laboratory measurements. We utilize VIIRS images co-geolocated with a Landsat TM image to precisely locate the bridge linear feature in the VIIRS images as a linear best fit to a straight line. We then utilize nonlinear optimization to compute the best fit equation of the VIIRS image measurements in the vicinity of the bridge to the developed model equation. From the found parameterization of the model equation, we derive the full-width at half-maximum as an approximation of the sensor field of view for all bands, and compare these on-orbit measured values with prelaunch laboratory results.

Improving the Algorithm of Extracting Regional Total Precipitable Water Vapor Over Land From MODIS Images

Precise estimation of total precipitable water vapor (TPW) with high temporal and spatial resolutions is of great importance in different disciplines. Moderate-Resolution Imaging Spectroradiometer (MODIS) is one of the sensors which have absorption and nonabsorption bands of water vapor. There is a standard algorithm to produce TPW product of MODIS (MOD05/MYD05) which uses the ratios of reflectances in strong, moderate, and weak absorption bands of water vapor to nonabsorption ones (transmission). This paper aims to present a method based on this algorithm to optimize TPW estimation in local scale. To do so, the western part of Iran was chosen as the study region. Terra MODIS images and MOD05 in clear-sky conditions related to the 100 days in four seasons of 2015–2016 were provided as the selected data. To validate and improve the results, TPW measured in six radiosonde stations and interpolated for overpass time of Terra was utilized. Four procedures were performed. In the first procedure, the coefficients of transmissions were extracted using linear least-squares technique, separately. For the second procedure, the coefficients were calculated in terms of the highest atmospheric transmission sensitivity to TPW for each absorption band separately, and in the third procedure, they were calculated simultaneously. In the last procedure, the errors from third one were modeled with a linear relationship between reflectance ratios of absorption bands. Based on the results, in highest accuracy, the coefficient of determination ${{{\text{R}}}}^{2}$ and Root Mean Square Error was 0.878 and 2.702 mm, respectively, which were acceptable comparing those of other researchers.

Cross-calibration of S-NPP VIIRS moderate resolution reflective solar bands against MODIS Aqua over dark water scenes.

The Visible Infrared Imaging Radiometer Suite (VIIRS) is being used to continue the record of Earth Science observations and data products produced routinely from National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS) measurements. However, the absolute calibration of VIIRS's reflected solar bands is thought to be biased, leading to offsets in derived data products such as aerosol optical depth (AOD) as compared to when similar algorithms are applied to different sensors. This study presents a cross-calibration of these VIIRS bands against MODIS Aqua over dark water scenes, finding corrections to the NASA VIIRS Level 1 (version 2) reflectances between approximately +1 % and -7 % (dependent on band) are needed to bring the two into alignment (after accounting for expected differences resulting from different band spectral response functions), and indications of relative trending of up to ^0.35 % per year in some bands. The derived calibration gain corrections are also applied to the VIIRS reflectance and then used in an AOD retrieval, and are shown to decrease the bias and total error in AOD across the midvisible spectral region compared to the standard VIIRS NASA reflectance calibration. The resulting AOD bias characteristics are similar to those of NASA MODIS AOD data products, which is encouraging in terms of multisensor data continuity.

Estimation of daily average downward shortwave radiation from MODIS data using principal components regression method: Fars province case study

Abstract Downward shortwave radiation is a key quantity in the land-atmosphere interaction. Since the moderate resolution imaging spectroradiometer data has a coarse temporal resolution, which is not suitable for estimating daily average radiation, many efforts have been undertaken to estimate instantaneous solar radiation using moderate resolution imaging spectroradiometer data. In this study, the principal components analysis technique was applied to capture the information of moderate resolution imaging spectroradiometer bands, extraterrestrial radiation, aerosol optical depth, and atmospheric water vapour. A regression model based on the principal components was used to estimate daily average shortwave radiation for ten synoptic stations in the Fars province, Iran, for the period 2009-2012. The Durbin-Watson statistic and autocorrelation function of the residuals of the fitted principal components regression model indicated that the residuals were serially independent. The results indicated that the fitted principal components regression models accounted for about 86-96% of total variance of the observed shortwave radiation values and the root mean square error was about 0.9-2.04 MJ m−2 d−1. Also, the results indicated that the model accuracy decreased as the aerosol optical depth increased and extraterrestrial radiation was the most important predictor variable among all.

Multiple shear bands in granular materials

The transition regime from quasi-static to dynamic shear regime is studied by discrete element method (DEM) and by means of a mesoscopic model. We show that at moderate shear rate multiple shear bands appear which eventually appear as a continuous shear profile for large shear rates. The model and the DEM simulations both show a minimum in the shear stress and a maximum for the number of simultaneous shear bands, however the position of the two do not coincide. The scaling analysis of the kinetic energy indicates that the peak in the latter is the relevant parameter. We also show how the long range order present in the quasi-static regime is gradually destroyed by the presence of multiple shear bands.

Using Ground Targets to Validate S-NPP VIIRS Day-Night Band Calibration

In this study, the observations from S-NPP VIIRS Day-Night band (DNB) and Moderate resolution bands (M bands) of Libya 4 and Dome C over the first four years of the mission are used to assess the DNB low gain calibration stability. The Sensor Data Records produced by NASA Land Product Evaluation and Algorithm Testing Element (PEATE) are acquired from nearly nadir overpasses for Libya 4 desert and Dome C snow surfaces. A kernel-driven bidirectional reflectance distribution function (BRDF) correction model is used for both Libya 4 and Dome C sites to correct the surface BRDF influence. At both sites, the simulated top-of-atmosphere (TOA) DNB reflectances based on SCIAMACHY spectral data are compared with Land PEATE TOA reflectances based on modulated Relative Spectral Response (RSR). In the Libya 4 site, the results indicate a decrease of 1.03% in Land PEATE TOA reflectance and a decrease of 1.01% in SCIAMACHY derived TOA reflectance over the period from April 2012 to January 2016. In the Dome C site, the decreases are 0.29% and 0.14%, respectively. The consistency between SCIAMACHY and Land PEATE data trends is good. The small difference between SCIAMACHY and Land PEATE derived TOA reflectances could be caused by changes in the surface targets, atmosphere status, and on-orbit calibration. The reflectances and radiances of Land PEATE DNB are also compared with matching M bands and the integral M bands based on M4, M5, and M7. The fitting trends of the DNB to integral M bands ratios indicate a 0.75% decrease at the Libya 4 site and a 1.89% decrease at the Dome C site. Part of the difference is due to an insufficient number of sampled bands available within the DNB wavelength range. The above results indicate that the Land PEATE VIIRS DNB product is accurate and stable. The methods used in this study can be used on other satellite instruments to provide quantitative assessments for calibration stability.

Measurement of the Band-to-Band Registration of the SNPP VIIRS Imaging System from On-Orbit Data.

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument was launched 28 October 2011 onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite. The VIIRS instrument is a whiskbroom system with 22 spectral and thermal bands split between 16 moderate resolution bands (M-bands), five imagery resolution bands (I-bands) and a day-night band. In this study we measure the along-scan and along-track band-to-band registration between the I-bands and M-bands from on-orbit data. This measurement is performed by computing the Normalized Mutual Information (NMI) between shifted image band pairs and finding the amount of shift required (if any) to produce the peak in NMI value. Subpixel accuracy is obtained by utilizing bicubic interpolation. The product of the NMI peak slope and the NMI peak value is shown to be a better criterion for evaluating the quality of the NMI result than just the NMI peak value. Registration shifts are found to be similar to pre-launch measurements and stable (within measurement error) over the instrument's first four years in orbit.

Adaptation of the Azimuthal Decomposition Technique to Jet Noise Measurements in Full-Scale Tests

To develop jet noise-reduction concepts, it is necessary to understand the physics underlying the noise-generation process. Decomposition of the sound field into azimuthal modes is one of the effective experimental methods that allows extracting subtle features of different types of noise sources. For turbulent flows, the interpretation of the noise analysis results using the azimuthal decomposition technique was developed by the authors in previous papers. In the present paper, a generalization of this method allowing the decomposition of the jet acoustic field into azimuthal modes by means of reduced number of microphones is developed. It is shown that jet noise measurements by only three microphones in each cross section allow reconstruction of three azimuthal mode directivities (axisymmetric, first, and second) for both low and moderate frequency bands. Furthermore, two-microphone measurements, provided the microphones are properly located, make it possible to reconstruct directivity of the axisymmetric mode and total directivity of the first and second modes. The latter method is shown to be suitable for using with an outdoor test bench. The modified methodology is first validated on a small-scale laboratory database. Next, it is applied to the jet of a real engine in ground tests. The information about the azimuthal modes properties may be used to investigate physical aspects of the large-scale jet noise sources.

JPSS-1 VIIRS Radiometric Characterization and Calibration Based on Pre-Launch Testing

The Visible Infrared Imaging Radiometer Suite (VIIRS) on-board the first Joint Polar Satellite System (JPSS) completed its sensor level testing on December 2014. The JPSS-1 (J1) mission is scheduled to launch in December 2016, and will be very similar to the Suomi-National Polar-orbiting Partnership (SNPP) mission. VIIRS instrument has 22 spectral bands covering the spectrum between 0.4 and 12.6 μm. It is a cross-track scanning radiometer capable of providing global measurements twice daily, through observations at two spatial resolutions, 375 m and 750 m at nadir for the imaging and moderate bands, respectively. This paper will briefly describe J1 VIIRS characterization and calibration performance and methodologies executed during the pre-launch testing phases by the government independent team to generate the at-launch baseline radiometric performance and the metrics needed to populate the sensor data record (SDR) Look-Up-Tables (LUTs). This paper will also provide an assessment of the sensor pre-launch radiometric performance, such as the sensor signal to noise ratios (SNRs), radiance dynamic range, reflective and emissive bands calibration performance, polarization sensitivity, spectral performance, response-vs-scan (RVS), and scattered light response. A set of performance metrics generated during the pre-launch testing program will be compared to both the VIIRS sensor specification and the SNPP VIIRS pre-launch performance.

Monitoring the NOAA Operational VIIRS RSB and DNB Calibration Stability Using Monthly and Semi-Monthly Deep Convective Clouds Time Series

The Visible and Infrared Imaging Radiometer Suite (VIIRS) onboard the Joint Polar Satellite System (JPSS)/Suomi National Polar-Orbiting Partnership (SNPP) satellite provide sensor data records for the retrievals of many environment data records. It is critical to monitor the VIIRS long-term calibration stability to ensure quality EDR retrieval. This study investigates the radiometric calibration stability of the NOAA operational SNPP VIIRS Reflective Solar Bands (RSB) and Day-Night-Band (DNB) using Deep Convective Clouds (DCC). Monthly and semi-monthly DCC time series for 10 moderate resolution bands (M-bands, M1–M5 and M7–M11, March 2013–September 2015), DNB (March 2013–September 2015, low gain stage), and three imagery resolution bands (I-bands, I1–I3, January 2014–September 2015) were developed and analyzed for long-term radiometric calibration stability monitoring. Monthly DCC time series show that M5 and M7 are generally stable, with a stability of 0.4%. DNB has also been stable since May 2013, after its relative response function update, with a stability of 0.5%. The stabilities of M1–M4 are 0.6%–0.8%. Large fluctuations in M1–M4 DCC reflectance were observed since early 2014, correlated with F-factor (calibration coefficients) trend changes during the same period. The stabilities of M8-M11 are from 1.0% to 3.1%, comparable to the natural DCC variability at the shortwave infrared spectrum. DCC mean band ratio time series show that the calibration stabilities of I1–I3 follow closely with M5, M7, and M10. Relative calibration changes were observed in M1/M4 and M5/M7 DCC mean band ratio time series. The DCC time series are generally consistent with results from the VIIRS validation sites and VIIRS/MODIS (the Moderate-resolution Imaging Spectroradiometer) simultaneous nadir overpass time series. Semi-monthly DCC time series for RSB M-bands and DNB were compared with monthly DCC time series. The results indicate that semi-monthly DCC time series are useful for stability monitoring at higher temporal resolution.

Land Cover Mapping of a Tropical Region by Integrating Multi-Year Data into an Annual Time Series

Generating annual land cover maps in the tropics based on optical data is challenging because of the large amount of invalid observations resulting from the presence of clouds and haze or high moisture content in the atmosphere. This study proposes a strategy to build an annual time series from multi-year data to fill data gaps. The approach was tested using the Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation index and spectral bands as input for land cover classification of Colombia. In a second step, selected ancillary variables, such as elevation, L-band Radar, and precipitation were added to improve overall accuracy. Decision-tree classification was used for assigning eleven land cover classes using the International Geosphere-Biosphere Programme (IGBP) legend. Maps were assessed by their spatial confidence derived from the decision tree approach and conventional accuracy measures using reference data and statistics based on the error matrix. The multi-year data integration approach drastically decreased the area covered by invalid pixels. Overall accuracy of land cover maps significantly increased from 58.36% using only optical time series of 2011 filtered for low quality observations, to 68.79% when using data for 2011 ± 2 years. Adding elevation to the feature set resulted in 70.50% accuracy.

On-orbit calibration of Visible Infrared Imaging Radiometer Suite reflective solar bands and its challenges using a solar diffuser

The reflective solar bands (RSBs) of the Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi National Polar-Orbiting Partnership satellite are calibrated by a solar diffuser (SD) panel whose performance is itself monitored by an accompanying solar diffuser stability monitor (SDSM). In this comprehensive work we describe the SD-based calibration algorithm of the RSBs, analyze the calibration data, and derive the performance results-the RSB calibration coefficients or F-factors-for the current three and a half years of mission. The application of the newly derived product of the SD bidirectional reflectance factor and the vignetting function for the SD screen and the newly derived SD degradation, so-called H-factors, effectively minimizes the artificial seasonal patterns in the RSB calibration coefficients due to the errors of these ingredient inputs. The full illumination region, the "sweet spot," during calibration events for SD view is carefully examined and selected to ensure high data quality and to reduce noise owing to non-fully illuminated samples. A time-dependent relative spectral response (RSR), coming from the large out-of-band contribution and the VIIRS optical system wavelength-dependent degradation, is derived from an iterative approach and applied in the SD calibration for each RSB. The result shows that VIIRS RSBs degrade much faster at near-infrared (NIR) and shortwave-infrared (SWIR) wavelength ranges due to the faster degradation of the rotating telescope assembly against the remaining part of the system. The gains of the VIIRS RSBs have degraded 2.0% (410nm, Band M1), 0.2% (443nm, Band M2), -0.3% (486nm, Band M3), 0.2% (551nm, Band M4), 6.2% (640nm, Band I1), 11.0% (671nm, Band M5), 21.3% (745nm, Band M6), 35.8% (862nm, Band I2), and 35.8% (862nm, Band M7), respectively, since launch and 24.8% (1238nm, Band M8), 18.5% (1378nm, Band M9), 11.5% (1610nm, Band I3), 11.5% (1610, Band M10), and 4.0% (2250nm, Band M11), respectively, since 20 January 2012. It is established that the SD calibration accurately catches the on-orbit RSB degradation according to the instrument design and the calibration algorithm. However, due to the inherent nonuniform degradation of the SD affecting especially the short wavelength bands and the lack of capability of the SDSM calibration to catch degradation beyond 935nm, the direct and the unmitigated application of the SD calibration result will introduce nonnegligible error into the calibration coefficients resulting in long-term drifts in the sensor data records and consequently the high-level products. We explicitly unveil the effect of the nonuniformity in SD degradation in the RSB calibration coefficients but also briefly discuss a critical yet simple mitigation to restore the accuracy of the calibration coefficients based on lunar observations. The methodology presented here thus remains intact as the cornerstone of the RSB calibration, and our derived RSB calibration coefficients represent the optimal result. This work has the most impact on the quality of the ocean color products that sensitively depend on the moderate visible and NIR bands (M1-M7), as well as the SWIR bands (M8, M10, and M11).

Suomi NPP VIIRS reflective solar band on-orbit radiometric stability and accuracy assessment using desert and Antarctica Dome C sites

The Visible Infrared Imaging Radiometer Suite (VIIRS) is a key instrument flying aboard Suomi NPP satellite. It is a follow on mission for NOAA series AVHRR and NASA MODIS. The radiometric stability and accuracy of VIIRS are critical to make its data useful for weather and climate applications. This study is focused on analyzing VIIRS radiometric performance using well established calibration sites and through the inter-comparison with other satellite instruments such as AQUA MODIS and Landsat 8 OLI. The paper analyzes stability of VIIRS reflective solar bands over more than two years by using sites such as Libya 4, Sudan 1 and Dome C. VIIRS absolute radiometric accuracy is quantified using AQUA MODIS over the above mentioned sites. For VIIRS band M11 (2.1μm), since there is no matching MODIS band pair, this study uses matching SWIR band from Landsat 8 OLI as a reference to quantify the absolute calibration accuracy of M11. The study shows that VIIRS moderate resolution reflective solar bands are stable with better than 0.5% for most of the bands with uncertainty on the order of 1%. After accounting the spectral differences, the absolute radiometric bias estimated through VIIRS and MODIS inter-calibration is within 2% for bands M1–5 and M10 and about 3% for bands M7–8. Similarly, M11 bias estimated using VIIRS and OLI inter-comparison is 5.4%.

Prelaunch Radiometric Characterization and Calibration of the S-NPP VIIRS Sensor

The Visible Infrared Imaging Radiometer Suite (VIIRS) is a key instrument onboard the Suomi National Polar-orbiting Partnership (S-NPP) spacecraft that was launched on October 28, 2011. VIIRS is designed to provide top of the atmosphere radiometric measurements and imaging of the entire planet Earth twice daily. It is a wide-swath (3040 km) cross-track scanning radiometer with spatial resolutions of 375 and 750 m at nadir for imaging and moderate bands, respectively. It has 22 spectral bands covering the spectrum between 0.4 and 12.5 μm, including 15 reflective solar bands and 7 thermal emissive bands. VIIRS observations are used to generate 22 environmental data records used by various operational applications and for climate research. This paper describes the prelaunch radiometric calibration and characterization methodologies used by the NASA VIIRS Characterization Support Team, including performance assessments for the reflective and emissive band radiometric calibration, the signal-to-noise ratios, dual gain transition, and dynamic range. Other aspects of the sensor performance such as scattered light response, response versus scan angle, polarization sensitivity, relative spectral response, and crosstalk will also be briefly described. A comprehensive set of performance metrics generated during the prelaunch testing program will be compared to the sensor requirements, and a list of lessons learned will be presented to enhance testing and performance assessment for future Joint Polar-Orbiting Satellite System VIIRS sensors.

On-orbit calibration of the Suomi National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite for ocean color applications.

The NASA Ocean Biology Processing Group (OBPG) developed two independent calibrations of the Suomi National Polar-Orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) moderate resolution reflective solar bands using solar diffuser measurements and lunar observations, and implemented a combined solar- and lunar-based calibration to track temporal changes in radiometric response of the instrument. Differences between the solar and lunar data sets have been used to identify issues and verify improvements in each. Linearization of the counts-to-radiance conversion yields a more consistent calibration at low radiance levels. Correction of a recently identified error in the VIIRS solar unit vector coordinate frame has been incorporated into the solar data and diffuser screen transmission functions. Temporal trends in the solar diffuser stability monitor data have been evaluated and addressed. Fits to the solar calibration time series show mean residuals per band of 0.067%-0.17%. Periodic residuals in the VIIRS lunar data are confirmed to arise from a wavelength-dependent libration effect for the sub-spacecraft point in the output of the U.S. Geological Survey Robotic Lunar Observatory photometric model of the Moon. Temporal variations in the relative spectral responses for each band have been assessed, and significant impact on band M1 (412 nm) lunar data has been identified and rectified. Fits to the lunar calibration time series, incorporating sub-spacecraft point libration corrections, show mean residuals per band of 0.069%-0.20%. Lunar calibrations have been used to adjust the solar-derived radiometric corrections for bands M1, M3, and M4. After all corrections, the relative differences in the solar and lunar calibrations for bands M1-M7 are 0.093%-0.22%. The OBPG has achieved a radiometric stability for the VIIRS on-orbit calibration that is commensurate with those achieved for SeaWiFS and Aqua MODIS, supporting the incorporation of VIIRS data into the long-term NASA ocean color data record.

Suomi NPP VIIRS prelaunch and on‐orbit geometric calibration and characterization

AbstractThe Visible Infrared Imaging Radiometer Suite (VIIRS) sensor was launched 28 October 2011 on the Suomi National Polar‐orbiting Partnership (SNPP) satellite. VIIRS has 22 spectral bands covering the spectrum between 0.412 µm and 12.01 µm, including 16 moderate resolution bands (M‐bands) with a nominal spatial resolution of 750 m at nadir, five imaging resolution bands (I‐bands) with a nominal spatial resolution of 375 m at nadir, and a day‐night band (DNB) with a near‐constant nominal 750 m spatial resolution throughout the scan. These bands are located in a visible and near‐infrared focal plane assembly (FPA), a shortwave and midwave infrared FPA, and a long‐wave infrared FPA. All bands, except the DNB, are coregistered for proper environmental data records retrievals. Observations from VIIRS instrument provide long‐term measurements of biogeophysical variables for climate research and polar satellite data stream for the operational community's use in weather forecasting and disaster relief and other applications. Well Earth‐located (geolocated) instrument data are important to retrieving accurate biogeophysical variables. This paper describes prelaunch pointing and alignment measurements, and the two sets of on‐orbit correction of geolocation errors, the first of which corrected error from 1300 m to within 75 m (20% I‐band pixel size) and the second of which fine‐tuned scan‐angle dependent errors, bringing VIIRS geolocation products to high maturity in one and a half years of the SNPP VIIRS on‐orbit operations. Prelaunch calibration and the on‐orbit characterization of sensor spatial impulse responses and band‐to‐band coregistration are also described.

Neck musculature fatigue affects specific frequency bands of postural dynamics during quiet standing

Proprioceptive input from the neck is important for maintenance of upright standing. Although neck musculature fatigue has been demonstrated to impair standing balance, there is limited understanding of the underlying postural mechanisms. This study aimed to further examine the effects of neck musculature fatigue on standing by using modern analysis of center of pressure (CoP) data. Forty-eight young healthy adults stood quietly on a balance board for 1min before and after performing repeated weight-resisted scapular elevation exercises. In a supplementary study on 20 participants, we examined (i) the effects of visual deprivation and (ii) the test–retest reliability of the traditional and wavelet-based CoP measures. Test–retest reliability of the CoP measures was moderate to good (intraclass correlation coefficients ranged from 0.58 to 0.94). With neck muscle fatigue or without vision, traditional measures of CoP velocity and standard deviation increased monotonically. Wavelet analysis revealed that CoP velocity within the ultralow (<0.10Hz) and moderate (1.56–6.25Hz) frequency bands increased post-fatigue. Without vision, CoP velocity increased in all but the ultralow frequency band. Our data suggest that post-fatigue, vision may be the main compensatory postural mechanism for altered neck proprioception. In conclusion, our findings reveal more nuances than the simple assertion that neck musculature fatigue increased postural sway and they advocate the use of wavelet analysis in examining postural mechanisms associated with neck proprioception.

Absorption of methane in the Saturn's atmosphere near 2009 equinox

The latitudinal variations of intensity of the absorption bands of methane on Saturn before and after the equinox in 2009 are considered, when the tilt of the planet's equator to the direction to the Sun was close to zero and both hemispheres were in equal insolation. The basic global changes of meridional distribution of absorption in the weak and moderate bands of methane in the wavelength range of 580-800 nm are extracted. The most characteristic feature of Saturn – a reduced absorption of methane in the equatorial belt – retains.

Bandemia with Normal White Blood Cell Counts Associated with Infection

ObjectiveMeasuring immature white blood cell forms (“bands”) has been considered clinically unnecessary. We performed this study to determine whether elevated band counts, with normal total white blood cells on admission, were associated with infection or in-hospital death. MethodsWe performed a retrospective cohort study including all patients admitted to the Christiana Care Health System 2-hospital, 1100-bed community-based academic health system in 2009 with normal white blood cells (3800-10,800 per mm3) on admission who had manual differentials performed. We defined our band groups as normal (≤10% bands and other immature cells), moderate (11%-19%), or high (≥20%). Via chart review, we ascertained vital signs and culture results for all patients with elevated bands and 407 randomly sampled patients with normal bands. Cultures likely to be contaminants were excluded. We used multivariable logistic regression to determine whether bandemia was predictive of significant positive cultures or death. ResultsOf 2342 patients, 167 (7.1%) had high bands and 205 (8.6%) had moderate bands. The mean white blood cell count was 7.5 cells/mm3, with no difference among groups. Bandemia was associated with increased odds of having any significant positive culture (adjusted odds ratio [OR], 2.0, 95% confidence interval [CI], 1.3-3.1 for moderate bands; adjusted OR, 2.8, 95% CI, 1.7-4.3 for high bands) and having positive blood cultures (adjusted OR, 3.8, 95% CI, 2.0-7.2 for moderate bands; adjusted OR, 6.2, 95% CI, 3.2-11.8 for high bands). Patients with moderate or high bands also had increased odds of in-hospital death (adjusted OR, 3.2, 95% CI, 1.7-6.1; adjusted OR, 4.7, 95% CI, 2.4-9.0, respectively). ConclusionsEven with normal total white blood cells, patients with moderate and high bandemia on admission had significantly increased odds of having positive cultures, including blood cultures, and of in-hospital mortality.