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Groundwater plays a critical role in the water- food-energy nexus and extensively supports global drinking water and food production. Despite the pressing demands for groundwater resources, groundwater withdrawals are not actively monitored in most regions. Thus, reliable methods are required to estimate withdrawals at local scales suitable for implementing sustainable groundwater management practices. Here, we combine publicly available remote sensing datasets into a deep learning framework for estimating groundwater withdrawals at high resolution (5 km) over the states of Arizona and Kansas in the USA. We compare ensemble machine learning and deep learning algorithms using groundwater pumping data from 2002–2019. Our research shows promising results in sub-humid and semi-arid (Kansas) and arid (Arizona) regions, which demonstrates the robustness and extensibility of this integrated approach. The success of this method indicates that we can effectively and accurately estimate local-scale groundwater withdrawals under different climatic conditions and aquifer properties.

Background: There is a paucity of data regarding osteochondral lesions of the tibial plafond (OLTPs), in part because they are far less common than osteochondral lesions of the talus. Purpose: To evaluate the topographical characteristics of OLTPs and outcomes after surgical intervention, while analyzing the level of evidence (LOE) and quality of evidence (QOE) of the included studies. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review of the MEDLINE, EMBASE, and Cochrane Library databases was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies reporting clinical data for OLTPs were included. The LOE and QOE of the included studies were evaluated using a 5-level grading system and the modified Coleman Methodology Score, respectively. Results: Included were 20 studies with 426 OLTPs; 4 studies were LOE 2 and 16 studies were LOE 4. Overall, 86.7% of OLTPs were associated with a traumatic history and/or previous ankle sprain. OLTPs were most commonly located in the centromedial region of the tibial plafond (30.4%), with the fewest number of OLTPs found in the anteromedial region of the tibial plafond (3.9%). In 17 of the studies, a total of 46.9% of OLTPs were associated with coexisting osteochondral lesions of the talus. The most frequently used surgical technique to treat OLTPs was microfracture, which resulted in good clinical outcomes at midterm follow-up. Conclusion: The results of this systematic review indicated that OLTPs are frequently preceded by ankle trauma and are often associated with coexisting osteochondral lesions of the talus. Clinical outcomes after arthroscopic intervention appear to produce good results in the midterm, but the low LOE, poor QOE, marked heterogeneity, and underreporting of the data confound any recommendation based on this systematic review.

Groundwater is the largest source of Earth’s liquid freshwater and plays a critical role in global food security. With the rising global demand for drinking water and increased agricultural product...

The Bidirectional Reflectance Distribution Function (BRDF) and Total Hemispherical Reflectance (THR) of two candidate black diffuse materials for the dim calibration targets of the NASA GSFC PACE Ocean Color Instrument (OCI) were reported in the SPIE conference last year. In this paper, we present new BRDF and THR results of the two black diffuse materials following additional UV exposure and solar wind tests. The BRDF measurements for five samples of each two black diffuse material were made at incident angles of 0° and 45° and at the wavelengths of 360 nm, 600 nm, and 1600 using the Table-top Goniometer (TTG) located in the Diffuser Calibration Laboratory (DCL) at NASA GSFC. The THR of the samples, 15 mm in diameter, was measured using a commercial UV-VIS-NIR spectrophotometer from 200 nm to 2500 nm. The spectral THR results of the two black diffuse materials exposed to UV and solar wind show an approximate 10 % higher reflectivity than the unexposed samples. The spectral profiles of the THR of the exposed and unexposed samples are relatively similar. The BRDF results at the incident angle of 45° show different trends in the forward and backward scattering regions, while those at normal incident angle are consistent with the THR results. We will also present the details of the samples’ surface features and the comparison of the 0°/45° BRDF and THR results, demonstrate the significance of background subtraction in the THR measurements for small, low reflectance samples, and discuss validation of BRDF scale, measurement repeatability, and major contributions of uncertainty.

Spectralon® is a high reflectance excellent Lambertian diffuser used to reflect sunlight for use as a calibrator for on-orbit and ground instruments. Radiometric calibration of the reflective bands in the 0.4 to 2.5μm wavelength range is performed by measuring the sunlight reflected from Spectralon® . Reflected sunlight is directly proportional to the Bidirectional Reflectance Distribution Function (BRDF) of the Spectralon® . On-orbit exposure to sunlight results in solarization due to solar UV. Previously, the rate / amount of solarization has varied as observed from on orbit measurements as well as laboratory UV exposure testing of samples. A method for determining whether a particular batch of Spectralon® has low solarization has been developed. This method relies on hemispherical reflectance measurements in the 0.25- 0.5 μm wavelength range before and after Spectralon® bake out. This method is reliable for as-made Spectralon® , not for contamination verification after shipment. We have also determined that additional Spectralon® bake outs do not change the as-made Spectralon® solarization rate. Knowledge of possible Spectralon solarization is important prior to its shipment to customers and eventual deployment in satellite and ground-based instrument calibration.

Levels of iron and iron-related proteins including ferritin are higher in the lung tissue and lavage fluid of individuals with chronic obstructive pulmonary disease (COPD), when compared to healthy controls. Whether more iron in the extracellular milieu of the lung associates with distinct clinical phenotypes of COPD, including increased exacerbation susceptibility, is unknown. We measured iron and ferritin levels in the bronchoalveolar lavage fluid (BALF) of participants enrolled in the SubPopulations and InteRmediate Outcome Measures In COPD (SPIROMICS) bronchoscopy sub-study (n = 195). BALF Iron parameters were compared to systemic markers of iron availability and tested for association with FEV1 % predicted and exacerbation frequency. Exacerbations were modelled using a zero-inflated negative binomial model using age, sex, smoking, and FEV1 % predicted as clinical covariates. BALF iron and ferritin were higher in participants with COPD and in smokers without COPD when compared to non-smoker control participants but did not correlate with systemic iron markers. BALF ferritin and iron were elevated in participants who had COPD exacerbations, with a 2-fold increase in BALF ferritin and iron conveying a 24% and 2-fold increase in exacerbation risk, respectively. Similar associations were not observed with plasma ferritin. Increased airway iron levels may be representative of a distinct pathobiological phenomenon that results in more frequent COPD exacerbation events, contributing to disease progression in these individuals.

Study abroad is considered a high-impact practice (HIP) in higher education. However, few discipline-specific study abroad courses are offered in computer science (CS) or physics. We implemented a CS/physics-based short-term study abroad course to England that focused on the history and science of information. This work provides insight for anyone considering the development and implementation of such a course at their own institution.

Introduction to special section on Modeling highly heterogeneous aquifers : Lessons learned in the last 30 years from the MADE experiments and others INTRODUCTION

Space-based astrophysical and remote sensing observations often require the detection and measurement of light originating from distant and relatively faint objects. These observations are highly susceptible to scattered light which may introduce imaging artifacts, obscure object details, and increase measurement noise. This paper describes the initial work of characterizing representative black materials used in coronagraph instruments and other spaceborne instruments. Measurements of “blackness” and the achieved reflectance of black silicon are provided in the spectral range from 400nm to 2500nm using 8o directional hemispherical measurements. The bidirectional reflectance of black silicon was also measured at discrete wavelengths, 633nm, and 1064nm, using the optical scatterometer located at NASA Goddard Space Flight Center’s Diffuser Calibration Laboratory (DCL). A 100mm diameter black silicon sample was fabricated and optically characterized. The BRDF of other well-known black materials such as Z306 and Fractal Black are also presented and discussed.

Many of NASA’s direct imaging of exoplanet missions and projects require fabricated coronagraph masks to control scattering and diffraction of light. The designed, patterned mask intended for the coronagraphic testbeds are highly absorptive in the visible range on non-metallic regions. In this work, we employed the cryogenic etching process to fabricate black silicon (BSi) to achieve a high aspect ratio (HAR) structures with higher etch rate than conventional reactive ion etching (REI). Recent bidirectional reflectance distribution function (BRDF) measurements of uniformly etched BSi on silicon wafer show highly diffusive BSi with a specular reflective component in the orders of seven magnitudes lower than the total hemispherical reflectance when the polarized or non-polarized incident beam is used.

Significant advances have been made in recent years by many countries and agencies in Earth observations via remote sensing instruments operated onboard LEO and GEO satellites. For passive optical sensors, reflective solar (RS) calibration remains extremely challenging in terms of calibration traceability, accuracy, stability, and consistency. The objective of this paper is to provide an overview of sensor RS calibration approaches with examples from the MODIS on the Terra and Aqua spacecraft and the VIIRS on the S-NPP and N-20. Lessons and calibration strategies developed to address various challenging issues are also discussed.

The Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) has successfully operated for more than three years since its launch in October 2011. Fifteen of the 22 VIIRS spectral bands are in the reflective solar spectral region, covering wavelengths from 0.41 to 2.3 $\mu\mbox{m}$ . Similar to its heritage sensor, i.e., Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA Terra and Aqua spacecraft, the measurements of these spectral bands are routinely calibrated on orbit by a solar diffuser (SD) and an SD stability monitor (SDSM) system. In addition, lunar observations are regularly scheduled and implemented, allowing the reflective solar band (RSB) calibration stability to be independently monitored. This paper provides an overview of VIIRS RSB on-orbit calibration activities and methodologies, with a focus on the approaches and strategies developed for the lunar calibration. Results derived from VIIRS lunar observations are used to assess its RSB on-orbit performance and to compare with that derived from the SD measurements. Also discussed in this paper are issues identified since launch through comparisons of VIIRS SD and lunar calibration, remaining challenges, and future improvements. Specifically, potential impacts due to degradation caused by the telescope mirror coating contamination on both SD and lunar calibration are assessed. As demonstrated in this paper, VIIRS lunar calibration activities have been successfully planned and executed, in support of its RSB on-orbit calibration. Overall, the long-term response trending derived from lunar calibrations has been consistent with that derived from SD observations. In addition to small features in SD measurements, noticeable seasonal variations, on the order of 1%, between the lunar measurements and the model have been identified. These variations are likely due to the effect of different lunar viewing angles on the lunar irradiance reference model. Future improvements to the sensor's lunar response trending could be achieved with an improved lunar irradiance model.

Category: Ankle; Sports; Trauma Introduction/Purpose: Osteochondral lesions of the talus (OLTs) account for the majority of osteochondral lesions (OCLs) of the tibiotalar joint, with osteochondral lesions of the tibial plafond (OLTP) being less commonly reported. The purpose of this systematic review was to evaluate the topographical characteristics of OLTPs, and outcomes following surgical intervention. Methods: A systematic review of the MEDLINE, EMBASE and Cochrane Library databases was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies reporting clinical data for OLTPs were included. The level and quality of evidence of the included studies was evaluated using the Modified Coleman Methodology Score. Results: Nineteen studies with 395 OLTPs were included. Overall, 75.9% of OLTPs were associated with a traumatic history and/or previous ankle sprain. OLTPs were most commonly located in the centromedial region of the tibial plafond (30.4%), with the fewest number of OLTPs found in the anterolateral region of the tibial plafond (3.9%). In total, 46.9% of OLTPs were associated with co-existing osteochondral lesions of the talus. Microfracture was the most frequently utilised surgical technique amongst the included studies, and reported good clinical outcomes at mid-term follow up. Four studies were level of evidence II and 15 studies were level of evidence IV. Conclusion: This systematic review has found that osteochondral lesions of the tibial plafond are not a rare clinical finding in the setting of ankle trauma and are often associated with co-existing osteochondral lesions of the talus. Clinical outcomes following arthroscopic intervention appear to produce good results in the mid-term, but the low level of evidence, poor quality of evidence, marked heterogeneity and underreporting of the data confounds any recommendation based on this systematic review.

A KHz Pulsed Laser Detection System was developed employing the concept of charge integration with an electrometer, in the NASA Goddard Space Flight Center, Code 618 Calibration Lab for the purpose of using the pulsed lasers for radiometric calibration. Comparing with traditional trans-impedance (current-voltage conversion) detection systems, the prototype of this system consists of a UV-Enhanced Si detector head, a computer controlled shutter system and a synchronized electrometer. The preliminary characterization work employs light sources running in either CW or pulsed mode. We believe this system is able to overcome the saturation issue when a traditional trans-impedance detection system is used with the pulsed laser light source, especially with high peak-power pulsed lasers operating at kilohertz repetition rates (e.g. Ekspla laser or KHz OPO). The charge integration mechanism is also expected to improve the stability of measurements for a pulsed laser light source overcoming the issue of peak-to-peak stability. We will present the system characterizations including signal-to-noise ratio and uncertainty analysis and compare results against traditional trans-impedance detection systems.

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 $\mu \hbox{m}$ , 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.

We present system-level responsivity calibration results of the visible and near infrared channels of JPSS-1 VIIRS in the reflective solar band (RSB) from bands M1( 412 nm) to M7 (865 nm). A monochromator-based method based on the Spectral Measurement Assembly (SpMA), and a laser-based calibration method based on Travelling-Spectral Irradiance and Radiance responsivity Calibrations using Uniform Sources (T-SIRCUS) were applied with different illumination methods to obtain the relative and absolute spectral responses (RSR and ASR). The spectral features of RSR for each band are verified by comparing to the component-level spectral transmittance of the VIIRS bandpass filters. Variation of RSR results of a single pixel/detector with respect to the band-averaged for each band is also investigated. Utilization of RSR results from SpMA and T-SIRCUS with different illumination methods as well as the component transmittance results enables us to recognize optical and electrical cross-talk from out-of-band, which is estimated at about 3 %. We also attempted to use the ASRs from T-SIRCUS to validate the gain coefficients derived from an independent radiometric calibration test using a broadband source. Three spectral shapes of flat spectral radiance, Tungsten lamp, and solar emission are used to simulate different scenarios for baseline, pre-launch calibration, and on-orbit calibration to verify the radiometric coefficients with the more accurate NIST-traceable calibration.

Changes in the directional reflectance properties of pressed and sintered polytetrafluoroethylene (PTFE) diffusers induced by exposure to vacuum ultraviolet (VUV) irradiation before and after controlled contamination with Pennzane are presented in this paper. A set of 99% reflective, white, optical grade diffuse calibration standards were irradiated with a VUV source positioned at 60? to the diffuser normal. The bidirectional reflectance distribution functions before and after contamination and VUV irradiation were measured and compared at a number of scatter geometries and wavelengths in the UV, VIS and IR spectral ranges. The 8? directional hemispherical reflectance?s were also measured and compared from 200?nm to 2500?nm. Our results indicate a measureable impact of VUV irradiation on pressed and sintered PTFE diffusers as manifested by a directional dependent change in their reflectance. Such an effect needs to be considered in the on-orbit deployment of PTFE diffusers.

The Visible Infrared Imaging Radiometer Suite (VIIRS) sensor aboard the Suomi National Polar-orbiting Partnership spacecraft has successfully operated since its launch in October 2011. The VIIRS collects data in 22 spectral bands that are calibrated by a set of onboard calibrators (OBC). In addition, lunar observations are made to independently track VIIRS long-term calibration stability for the reflective solar bands (RSB). This paper provides an overview of VIIRS OBC functions as well as its on-orbit operation and calibration activities. It also describes sensor calibration methodologies and demonstrates VIIRS on-orbit performance from launch to present. Results reported in this paper include on-orbit changes in sensor spectral band responses, detector noise characterization, and key calibration parameters. Issues identified and their potential impacts on sensor calibration are also discussed. Since launch, the VIIRS instrument nominal operation temperature has been stable to within ±1.0 K. The cold focal plane temperatures have been well controlled, with variations of less than 20 mK over a period of 1.5 years. In general, changes in thermal emissive bands (TEB) detector responses have been less than 0.5%. Despite large response degradation in several near-infrared and short-wave infrared bands and large SD degradation at short visible wavelengths, the VIIRS sensor and OBC overall performance has been excellent postlaunch. The degradation caused by the telescope mirror coating contamination has been modeled and its impact addressed through the use of modulated relative spectral response in the improved calibration and the current sensor data record data production. Based on current instrument characteristics and performance, it is expected that the VIIRS calibration will continue to meet its design requirements, including RSB detector signal to noise ratio and TEB detector noise equivalent temperature difference, throughout its 7 year design lifetime.

Category: Midfoot/Forefoot Introduction/Purpose: Hallux rigidus is a common degenerative joint condition of the foot. In advanced stages of the disease, extensive procedures have been utilized including Keller arthroplasty, interpositional arthroplasty (IPA), arthrodesis, total joint replacement or synthetic cartilage replacement. IPA is a surgical procedure that attempts to maintain joint motion through insertion of a biologic spacer into the joint. However, there is still a paucity of overall clinical data regarding outcomes and complication rates following IPA procedure for the treatment of hallux rigidus.The purpose of the current study was to systematically review the outcomes of IPA in the treatment of hallux rigidus. Methods: A systematic search of the MEDLINE, EMBASE and Cochrane Library databases was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Outcomes collected and analysed included: AOFAS score, VAS score, SF36 score, range of motion, radiographic parameters, and postoperative complications. The level and quality of evidence were recorded and assessed. Results: Sixteen studies with a total of 433 patients met inclusion/exclusion criteria. The mean AOFAS improved from 56.8±7.3 (range, 43.2-64.3) preoperatively to 84.0±6.7 (range, 71.6-90.0) postoperatively. The preoperative weighted mean total ROM was 37.7±16.2 degrees and the postoperative weighted mean total ROM was 60.3±13.4 degrees. Five studies examined joint space narrowing on plain radiographs. The mean preoperative joint space was 1.2±0.2 mm (range, 1 -1.5) and the mean postoperative joint space was 2.5±0.5 mm (range, 1.9-3). The complication rate was 18.2% with metatarsalgia as the most commonly reported complication. One study was Level III and 15 studies were Level IV. Conclusion: This systematic review demonstrates improvement in functional and ROM outcomes following IPA. The procedure however has a high complication rate. There is a low level and quality of evidence in the current literature with inconsistent reporting of data. Therefore, further well designed studies must be carried out to determine the efficacy of IPA in the treatment of hallux rigidus.

The majority of slug tests done at sites of shallow groundwater contamination are performed in wells screened across the water table and are affected by mechanisms beyond those considered in the standard slug-test models. These additional mechanisms give rise to a number of practical issues that are yet to be fully resolved; four of these are addressed here. The wells in which slug tests are performed were rarely installed for that purpose, so the well design can result in problematic (small signal to noise ratio) test data. The suitability of a particular well design should thus always be assessed prior to field testing. In slug tests of short duration, it can be difficult to identify which portion of the test represents filter-pack drainage and which represents formation response; application of a mass balance can help confirm that test phases have been correctly identified. A key parameter required for all slug test models is the casing radius. However, in this setting, the effective casing radius (borehole radius corrected for filter-pack porosity), not the nominal well radius, is required; this effective radius is best estimated directly from test data. Finally, although conventional slug-test models do not consider filter-pack drainage, these models will yield reasonable hydraulic conductivity estimates when applied to the formation-response phase of a test from an appropriately developed well.

Use of diamond as a semiconductor material suffers from the high activation energy of all known impurity dopants (0.37 eV for Boron, 0.6 eV for Phosphorous). To achieve the simultaneous carrier concentration and mobility desired for devices operating at room temperature, growth of a nanometric thick ‘delta’ layer doped to above the metal insulator transition adjacent to high mobility intrinsic material can provide a 2D high mobility conduction layer. Critical to obtaining the enhanced mobility of the carriers in the layer next to the ‘delta’ doped layer is the abruptness of the doping interface. Single and multiple nanometer thick epitaxial layers of heavily boron ‘delta’ doped diamond have been grown on high quality, intrinsic lab grown diamond single crystals. These layers were grown in a custom microwave plasma activated chemical vapor deposition reactor based on a rapid reactant switching technique. Characterization of the ‘delta’ layers by various analytical techniques will be presented. Electrical measurements demonstrating enhanced hole mobility (100 to 800 cm2/V sec) as well as other electrical characterizations will be presented.

The first VIIRS instrument has successfully operated for more than 4 years on-board the Suomi-National Polar-orbiting Partnership (S-NPP) spacecraft. The sensor data records (SDR) derived from VIIRS on-orbit observations have been used to produce many environment data records (EDR), enabling a wide range of applications by the users from operational and research community. This paper provides an overview of instrument operations and its calibration activities, and presents an update of its radiometric performance, in terms of on-orbit changes in sensor spectral band responses and noise characterization. It also describes the effort made to improve sensor calibration, and the strategies developed in support of producing consistent SDR and, consequently, the EDR with improved quality.

The MODIS has successfully operated on-board the NASA's EOS Terra and Aqua spacecraft for more than 16 and 14 years, respectively. MODIS instrument was designed with stringent calibration requirements and comprehensive on-board calibration capability. In the reflective solar spectral region, Aqua MODIS has performed better than Terra MODIS and, therefore, has been chosen by the Global Space-based Inter-Calibration System (GSICS) operational community as the calibration reference sensor in cross-sensor calibration and calibration inter-comparisons. For the same reason, it has also been used by a number of earth observing sensors as their calibration reference. Considering that Aqua MODIS has already operated for nearly 14 years, it is essential to transfer its calibration to a follow-on reference sensor with a similar calibration capability and stable performance. The VIIRS is a follow-on instrument to MODIS and has many similar design features as MODIS, including their on-board calibrators (OBC). As a result, VIIRS is an ideal candidate to replace MODIS to serve as the future GSICS reference sensor. Since launch, the S-NPP VIIRS has already operated for more than 4 years and its overall performance has been extensively characterized and demonstrated to meet its overall design requirements. This paper provides an overview of Aqua MODIS and S-NPP VIIRS reflective solar bands (RSB) calibration methodologies and strategies, traceability, and their on-orbit performance. It describes and illustrates different methods and approaches that can be used to facilitate the calibration reference transfer, including the use of desert and Antarctic sites, deep convective clouds (DCC), and the lunar observations.

The VIIRS instrument on board the S-NPP spacecraft has successfully operated for more than four years since its launch in October 2011. Many VIIRS environmental data records (EDR) have been continuously generated from its sensor data records (SDR) with improved quality, enabling a wide range of applications in support of users in both the operational and research communities. This paper provides a brief review of sensor on-orbit calibration methodologies for both the reflective solar bands (RSB) and the thermal emissive bands (TEB) and an overall assessment of their on-orbit radiometric performance using measurements from instrument on-board calibrators (OBC), as well as regularly scheduled lunar observations. It describes and illustrates changes made and to be made for calibration and data quality improvements. Throughout the mission, all of the OBC have continued to operate and function normally, allowing critical calibration parameters used in the data production systems to be derived and updated. The temperatures of the on-board blackbody (BB) and the cold focal plane assemblies are controlled with excellent stability. Despite large optical throughput degradation discovered shortly after launch in several near- and short-wave infrared spectral bands and strong wavelength-dependent solar diffuser degradation, the VIIRS overall performance has continued to meet its design requirements. Also discussed in this paper are challenging issues identified and efforts to be made to further enhance the sensor calibration and characterization, thereby maintaining or improving data quality.

Traditionally, satellite instruments that measure Earth-reflected solar radiation in the visible and near infrared wavelength regions have been calibrated for radiance responsivity in a two-step method. In the first step, the relative spectral response (RSR) of the instrument is determined using a nearly monochromatic light source such as a lamp-illuminated monochromator. These sources do not typically fill the field of view of the instrument nor act as calibrated sources of light. Consequently, they only provide a relative (not absolute) spectral response for the instrument. In the second step, the instrument views a calibrated source of broadband light, such as a lamp-illuminated integrating sphere. The RSR and the sphere's absolute spectral radiance are combined to determine the absolute spectral radiance responsivity (ASR) of the instrument. More recently, a full-aperture absolute calibration approach using widely tunable monochromatic lasers has been developed. Using these sources, the ASR of an instrument can be determined in a single step on a wavelength-by-wavelength basis. From these monochromatic ASRs, the responses of the instrument bands to broadband radiance sources can be calculated directly, eliminating the need for calibrated broadband light sources such as lamp-illuminated integrating spheres. In this work, the traditional broadband source-based calibration of the Suomi National Preparatory Project Visible Infrared Imaging Radiometer Suite sensor is compared with the laser-based calibration of the sensor. Finally, the impact of the new full-aperture laser-based calibration approach on the on-orbit performance of the sensor is considered.

Spatial variations in hydraulic conductivity (K) are a primary control on contaminant movement in groundwater, but characterization of these variations has proven difficult. Over the last two decades, significant progress has been made in utilizing Direct Push (DP) technology to characterize K variations in unconsolidated settings. Profiling methods have been developed based on empirical correlations between K and more readily evaluated formation properties and on the formation response to water injection or extraction. The latter (hydraulic) methods appear to have the most potential. Initial work on these methods involved adaptation of conventional well tests, but recent efforts have better exploited DP capabilities. The High-Resolution K and continuous Direct Push Injection Logger (DPIL) methods are the most promising approaches. Both provide high-resolution (0.015 m) K profiles, although the DPIL profile is only qualitative in nature. Currently, the K range of both is approximately 0.001 to 60 m/d, but that range should increase in the near future.

We offer a cautionary note in response to an increasing level of enthusiasm regarding high-resolution aquifer characterization with hydraulic tomography. We use synthetic examples based on two recent field experiments to demonstrate that a high degree of nonuniqueness remains in estimates of hydraulic parameter fields even when those estimates are based on simultaneous analysis of a number of carefully controlled hydraulic tests. We must, therefore, be careful not to oversell the technique to the community of practicing hydrogeologists, promising a degree of accuracy and resolution that, in many settings, will remain unattainable, regardless of the amount of effort invested in the field investigation. No practically feasible amount of hydraulic tomography data will ever remove the need to regularize or bias the inverse problem in some fashion in order to obtain a unique solution. Thus, along with improving the resolution of hydraulic tomography techniques, we must also strive to couple those techniques with procedures for experimental design and uncertainty assessment and with other more cost-effective field methods, such as geophysical surveying and, in unconsolidated formations, direct-push profiling, in order to develop methods for subsurface characterization with the resolution and accuracy needed for practical field applications.

A Light-Emitting Diode (LED)-driven integrating sphere light source has been fabricated and assembled in the NASA Goddard Space Flight Center (GSFC) Code 618 Biospheric Sciences Laboratory’s Calibration Facility. This light source is a 30.5 cm diameter integrating sphere lined with Spectralon. A set of four LEDs of different wavelengths are mounted on the integrating sphere’s wall ports. A National Institute of Standards and Technology (NIST) characterized Si detector is mounted on a port to provide real-time monitoring data for reference. The measurement results presented here include the short-term and long-term stability and polarization characterization of the output from this LED-driven integrating sphere light source. As an initial application, this light source is used to characterize detector/pre-amplifier gain linearity in light detection systems. The measurement results will be presented and discussed.

The VIS/NIR bands polarization sensitivity of Joint Polar Satellite Sensor 1 (JPSS1) Visible/Infrared Imaging Radiometer Suite (VIIRS) instrument was measured using a broadband source. While polarization sensitivity for bands M5-M7, I1, and I2 was less than 2.5%, the maximum polarization sensitivity for bands M1, M2, M3, and M4 was measured to be 6.4%, 4.4%, 3.1%, and 4.3%, respectively with a polarization characterization uncertainty of less than 0.3%. A detailed polarization model indicated that the large polarization sensitivity observed in the M1 to M4 bands was mainly due to the large polarization sensitivity introduced at the leading and trailing edges of the newly manufactured VISNIR bandpass focal plane filters installed in front of the VISNIR detectors. This was confirmed by polarization measurements of bands M1 and M4 bands using monochromatic light. Discussed are the activities leading up to and including the instruments two polarization tests, some discussion of the polarization model and the model results, the role of the focal plane filters, the polarization testing of the Aft-Optics-Assembly, the testing of the polarizers at Goddard and NIST and the use of NIST's T-SIRCUS for polarization testing and associated analyses and results.

Background and purpose To compare early (3 and 6 month) and later (12 and 24 month) functional outcomes of stage III and IV (M0) oropharyngeal squamous cancer patients treated in sequential cohorts with 3D conformal (3DCRT) or intensity modulated radiotherapy (IMRT). Patients and methods 200 patients in sequential population based cohorts of 83 and 117 patients treated at a single institution with 3DCRT and then IMRT respectively were prospectively assessed at pre-treatment and 3, 6, 12 and 24 months post treatment. A standard functional outcomes protocol including performance status (KPS, ECOG), 3 Performance Status scales for Head and Neck (PSS-HN), the Royal Brisbane Hospital Outcome Measure for Swallowing (RBHOMS), Voice Handicap Index-10 (VHI-10) and self-rated xerostomia were applied. Results Mean age at diagnosis was 59 years. The primary site was base of tongue in 77 and tonsil or soft palate in 123 patients. Median follow up was 2.5 years for the second cohort. Concomitant therapy was used in 159 (79.5%). Overall survival at 3 years was 75.6% and 71.5% for IMRT and 3DCRT cohorts respectively (not significant). A multiple imputation technique was used to estimate missing values in order to avoid a healthy patient bias. KPS and ECOG reached nadirs at 3 to 6 months but approached baseline values at 12 to 24 months and did not differ by treatment. The 3 PSS-HN scales, Eating in Public (p

Purpose: Radiation oncology’s popularity as a career in Canada has surged in the past 5 years. Consequently, resident numbers in Canadian radiation oncology residencies are at all-time highs. This study aimed to survey Canadian radiation oncology residents about their opinions of their specialty and training experiences. Methods and Materials: Residents of Canadian radiation oncology residencies that enroll trainees through the Canadian Resident Matching Service were identified from a national database. Residents were mailed an anonymous survey. Results: Eight of 101 (7.9%) potential respondents were foreign funded. Fifty-two of 101 (51.5%) residents responded. A strong record of graduating its residents was the most important factor residents considered when choosing programs. Satisfaction with their program was expressed by 92.3% of respondents, and 94.3% expressed satisfaction with their specialty. Respondents planning to practice in Canada totaled 80.8%, and 76.9% plan to have academic careers. Respondents identified job availability and receiving adequate teaching from preceptors during residency as their most important concerns. Conclusions: Though most respondents are satisfied with their programs and specialty, job availability and adequate teaching are concerns. In the future, limited time and resources and the continued popularity of radiation oncology as a career will magnify the challenge of training competent radiation oncologists in Canada.

Comparison of independent measurement results allows an assessment of the accuracy of the underlying methods. In this work, four multichannel filter radiometers were calibrated using tunable laser-illuminated and lamp-illuminated integrating sphere sources (ISSs). The determination of the radiance of the laser-illuminated ISS is based on electrical substitution radiometry at cryogenic temperatures and dimensional metrology of circular apertures. The determination of the spectral radiance of the lamp-illuminated ISS is based on blackbody physics, referenced to the freezing temperature of gold. By calibrating the filter radiometers using both methods, we compare the `detector-based' to the `source-based' radiance scale at the National Institute of Standards and Technology (NIST).

In radiometry or pyrometry, radiometers are often used to assign the spectral radiance or radiance temperatures of sources using ratios of signals which can differ by several decades. For performing ratios between such sources with low uncertainties, the linearity of the detectors used in the transfer radiometers needs to be characterized. The linearity of InGaAs photodiodes has been studied using the flux-addition method using a broadband infrared source with a visible-blocking filter. Using this technique, 18 InGaAs photodiodes from four different vendors were studied without spectral filtering in a broad wavelength region from 900 nm to 1700 nm with the diodes underfilled by the incident flux. The linearity of InGaAs photodiodes was determined within the range of photocurrents from 10−8 A to 10−4 A. All the InGaAs photodiodes demonstrated linearity from 10−7 A to 10−4 A within the expanded uncertainties of 0.08% (k = 2). The uncertainty in the linearity measurement below 10−8 A is increased due to the increased noise in the photocurrent arising from the feedback resistance of the transimpedance amplifier being greater than the shunt resistance of the photodiode.

When addressing tobacco control and smoking cessation measures, the homeless have been perceived as a difficult to reach population. The purpose of this study was to examine the smoking characteristics of a homeless population. Data were derived from a larger study that examined smoking among inner–city residents. Homeless smokers (n = 107) were compared to nonhomeless smokers (n = 491) on sociodemographics, smoking characteristics, motivation to quit, and smoking cessation experiences. Results showed that homeless smokers were more likely to be white, smoke more cigarettes per day, initiate smoking at a younger age, and have a longer smoking history. Knowledge about the risks of smoking and the benefits of quitting was equally high in both groups. Homeless smokers were less likely to be preparing to quit smoking compared to nonhomeless smokers. These factors place homeless smokers at increased risk of tobacco–related diseases. Programs are needed to design and test effective cessation interventions for homeless smokers.

A new direct-push procedure has been developed for the purpose of conducting discrete-interval slug tests to define vertical variations in hydraulic conductivity (K.) This approach is an extension of existing dual-tube methods developed for soil sampling. In this procedure, nested rods (tubes) are simultaneously advanced to predetermined test intervals. The inner rods are then removed and a screen is inserted into the formation for slug testing and possible water sampling. Once testing and sampling are completed, the screen is retrieved, the inner rods reinserted, and the system is advanced to the next test interval. A series of field tests were performed in a highly permeable sand and gravel aquifer to assess the effectiveness of this new approach. Dual-tube profiling results were compared to multilevel slug tests conducted in conventional monitoring wells for intervals in which hydraulic conductivity ranged from 175 ft/day to over 800 ft/day. An initial evaluation found that the dual-tube profiling results were in good agreement (< or =12 percent difference) with K values obtained from multilevel slug tests in the closest monitoring well. Two more-detailed profiles demonstrate that the dual-tube method can effectively delineate small-scale vertical and horizontal variations in hydraulic conductivity. This field assessment shows that the dual-tube method is an accurate and efficient procedure for obtaining information about spatial variations in hydraulic conductivity. This information can be useful for selecting intervals for well installations, for assessment of various remediation alternatives, and for identifying preferential flow paths and other features that can control contaminant movement in the subsurface. The information is obtained without the need for permanent wells. Because this is a direct-push procedure, drill cuttings are eliminated and the volume of development water generated is significantly reduced.

The potential of direct-push technology for hydraulic characterization of saturated flow systems was investigated at a field site with a considerable degree of subsurface control. Direct-push installations were emplaced by attaching short lengths of screen (shielded and unshielded) to the bottom end of a tool string that was then advanced into the unconsolidated sediments. A series of constant-rate pumping tests were performed in a coarse sand and gravel aquifer using direct-push tool strings as observation wells. Very good agreement (within 4%) was found between hydraulic conductivity (K) estimates from direct-push installations and those from conventional wells. A program of slug tests was performed in direct-push installations using small-diameter adaptations of solid-slug and pneumatic methods. In a sandy silt interval of moderate hydraulic conductivity, K values from tests in a shielded screen tool were in excellent agreement (within 2%) with those from tests in a nearby well. In the coarse sand and gravel aquifer, K values were within 12% of those from multilevel slug tests at a nearby well. However, in the more permeable portions of the aquifer (K > 70 m/day), the smaller-diameter direct-push rods (0.016 m inner diameter [I.D.]) attenuated test responses, leading to an underprediction of K. In those conditions, use of larger-diameter rods (e.g., 0.038 m I.D.) is necessary to obtain kappa values representative of the formation. This investigation demonstrates that much valuable information can be obtained from hydraulic tests in direct-push installations. As with any type of hydraulic test, K estimates are critically dependent on use of appropriate emplacement and development procedures. In particular, driving an unshielded screen through a heterogeneous sequence will often lead to a buildup of low-K material that can be difficult to remove with standard development procedures.

The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission is designed to make SItraceable measurements and provide a long-term benchmarking data record for the detection, projection, and attribution of changes in the Earths climate system. The CLARREO mission will include instruments operating in the reflected solar (RS) wavelength region from 320 nm to 2300 nm and the thermal infrared wavelength region from 5 μm to 50 μm. A major objective of CLARREO is to improve the accuracy of SI-traceable absolute calibration in the infrared and reflected solar wavelengths. In this paper we describe a tool developed to assess the uncertainty of the top of the atmosphere (TOA) Earth reflectance, to be measured by the CLARREO reflected solar (RS) instrument. The tool provides an error estimate based on the preliminary prototype instrument design. The on-orbit calibration approach currently implemented in the tool uses a direct view of the Sun through an attenuator. Several attenuation approaches are considered and incorporated as options of viewing the Sun through: a pinhole; a perforated plate; a combination between a pinhole and reduced exposure time and/or a neutral density (ND) filter. Additional approaches can readily be implemented. The tool is realized in Excel and is intended to facilitate error budget assessments specifically of the CLARREO RS instrument. Towards deriving a realistic estimate we started compiling a database of values for the various uncertainty contributors using results from testing prototypes or from other missions utilizing similar design.

Steward et al. (1) assess the hydrologic and agricultural future of the High Plains Aquifer. We have many concerns about hydrologic aspects of their study and describe the most significant here.

Commonly used analytical approaches for estimation of pumping-induced drawdown and stream depletion are based on a series of idealistic assumptions about the stream-aquifer system. A new solution has been developed for estimation of drawdown and stream depletion under conditions that are more representative of those in natural systems (finite width stream of shallow penetration adjoining an aquifer of limited lateral extent). This solution shows that the conventional assumption of a fully penetrating stream will lead to a significant overestimation of stream depletion (> 100%) in many practical applications. The degree of overestimation will depend on the value of the stream leakance parameter and the distance from the pumping well to the stream. Although leakance will increase with stream width, a very wide stream will not necessarily be well represented by a model of a fully penetrating stream. The impact of lateral boundaries depends upon the distance from the pumping well to the stream and the stream leakance parameter. In most cases, aquifer width must be on the order of hundreds of stream widths before the assumption of a laterally infinite aquifer is appropriate for stream-depletion calculations. An important assumption underlying this solution is that stream-channel penetration is negligible relative to aquifer thickness. However, an approximate extension to the case of nonnegligible penetration provides reasonable results for the range of relative penetrations found in most natural systems (up to 85%). Since this solution allows consideration of a much wider range of conditions than existing analytical approaches, it could prove to be a valuable new tool for water management design and water rights adjudication purposes.

Laboratory measurements of the bidirectional reflectance distribution function (BRDRF) of diffuse reflectors are required to support calibration in the Earth Observing System (EOS) program of the National Aeronautics and Space Administration.

We present an analysis of the transmission properties of index-shifted Bragg gratings. Theoretical predictions of the transmission properties of these gratings are obtained using a generalized transfer matrix method. Our theoretical predictions show that a precise modification of the average refractive index of Bragg gratings can lead to the generation of narrowband transmission windows within a broad low transmission band. The theoretical predictions are compared to experimental results obtained with fiber Bragg gratings.

The identification of spatial variations in hydraulic conductivity (K) on a scale of relevance for transport investigations has proven to be a considerable challenge. Recently, a new field method for the estimation of interwell variations in K has been proposed. This method, hydraulic tomography, essentially consists of a series of short-term pumping tests performed in a tomographic-like arrangement. In order to fully realize the potential of this approach, information about lateral and vertical variations in pumping-induced head changes (drawdown) is required with detail that has previously been unobtainable in the field. Pumping tests performed in networks of multilevel sampling (MLS) wells can provide data of the needed density if drawdown can accurately and rapidly be measured in the small-diameter tubing used in such wells. Field and laboratory experiments show that accurate transient drawdown data can be obtained in the small-diameter MLS tubing either directly with miniature fiber-optic pressure sensors or indirectly using air-pressure transducers. As with data from many types of hydraulic tests, the quality of drawdown measurements from MLS tubing is quite dependent on the effectiveness of well development activities. Since MLS ports of the standard design are prone to clogging and are difficult to develop, alternate designs are necessary to ensure accurate drawdown measurements. Initial field experiments indicate that drawdown measurements obtained from pumping tests performed in MLS networks have considerable potential for providing valuable information about spatial variations in hydraulic conductivity.

The diffraction efficiency of volume holographic gratings can depend strongly on the state of polarization of the incident light. We have experimentally studied the diffraction properties of highly polarization-sensitive, volume holographic gratings in the highly modulated regime formed using DMP-128 photopolymer and have compared data in this regime to existing theories. We have found that rigorous coupled-wave theory accurately predicts experimental measurements of the diffraction efficiency in the highly-modulated, polarization-sensitive regime, while a simpler two-wave theory modified to include form birefringence does not.

The Earth Observing System (EOS) is an international, 18-year program in global remote sensing of the Earth comprising multiple instruments flown on several satellite platforms. The first EOS platform, AM1, scheduled for launch in 1998, includes five instruments designed to make radiometric and reflectance measurements of the Earth over a wavelength range extending from the visible to the thermal infrared. The goal of the EOS-AM1 platform and instruments is to advance the scientific understanding of the Earth in the areas of clouds, aerosols, radiative balance, terrestrial and oceanic characterization, and the carbon cycle. In order to achieve this goal, the EOS-AM1 instruments must produce state-of-the-art accurate, precise, and consistent radiance and reflectance measurements over their five-year lifetimes. In addition, the production of continuous remote-sensing data from multiple instruments on several platforms requires that the remote-sensing measurements of the AM1 platform be radiometrically tied to the measurements made by instruments on successive platforms. This is achieved through careful prelaunch and postlaunch instrument calibration, cross-calibration, and level 1B data validation (i.e. vicarious calibration). This paper presents an overview of the calibration, cross-calibration, and level 1B data validation strategy for the AM1 platform.