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(Abridged) We show that sizeable fractions of incident ionizing radiation from stochastic astrophysical sources can be redistributed to biologically and chemically important UV wavelengths, a significant fraction of which can reach the surface. This redistribution is mediated by secondary electrons, resulting from Compton scattering and X-ray photoabsorption, with energies low enough to excite atmospheric molecules and atoms, resulting in a rich aurora-like spectrum. We calculate the fraction of energy redistributed into biologically and chemically important wavelength regions for spectra characteristic of stellar flares and supernovae using a Monte-Carlo transport code written for this problem and then estimate the fraction of this energy that is transmitted from the atmospheric altitudes of redistribution to the surface for a few illustrative cases. Redistributed fractions are found to be of order 1%, even in the presence of an ozone shield. This result implies that planetary organisms will be subject to mutationally significant, if intermittent, fluences of UV-B and harder radiation even in the presence of a narrow-band UV shield like ozone. We also calculate the surficial transmitted fraction of ionizing radiation and redistributed ultraviolet radiation for two illustrative evolving Mars atmospheres whose initial surface pressures were 1 bar. Our results suggest that coding organisms on planets orbiting low-mass stars (and on the early Earth) may evolve very differently than on contemporary Earth, with diversity and evolutionary rate controlled by a stochastically varying mutation rate and frequent hypermutation episodes., 21 pages, 2 figures, accepted for publication in Origins of Life and Evolution of the Biosphere

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Cross-track Infrared Sounder (CrIS) is a Fourier Transform interferometric sensor that measures earth radiances at high spectral resolution. Algorithms use the data to provide pressure, temperature, and moisture profiles of the atmosphere. The CrIS instrument contains photovoltaic detectors with spectral cut-offs denoted by SWIR [ λc(98 K) ~ 5 µm], MWIR [λc(98 K) ~ 9 µm] and LWIR [λc(81 K) ~ 15 µm]. The CrIS instrument requires large-area, photovoltaic detectors with state-of-art detector performance at temperatures attainable with passive cooling. For example, detectors as large as 1 mm in diameter are required. To address these needs, Molecular Beam Epitaxy (MBE) is used to grow the appropriate bandgap n-type Hg 1-xCdxTe on lattice matched CdZnTe. The p-side is obtained via arsenic implantation followed by appropriate annealing steps. 1/f noise in photovoltaic Hg 1-xCdxTe detectors is a critical parameter that limits the sensitivity of the CrIS instrument. Therefore, an understanding of the mechanisms that impact noise currents in a photovoltaic detector is of great importance. MBE grown Hg1-xCdxTe Double Layer Planar Heterostructure (DLPH) photovoltaic detectors have been characterized to determine the dominant mechanisms impacting detector I-V performance. Excess low frequency noise has been measured on a number of 1000 µm diameter active area detectors of varying “quality” (i.e. having a wide range of I-V performance at 78 K). The 1/f noise was measured as a function of bias, cutoff wavelength, and under illuminated conditions. For SWIR [λc(98 K) ~ 5 µm] detectors at 98 K, minimal 1/f noise was measured. The noise was white and in the mid 10 -15 A/Hz 1/2 range. For MWIR [λc(98 K) ~ 9 µm] detectors, the most important point to note is that the photo-induced noise spectra are nearly identical at 0 mV and 100 mV reverse bias, with a noise current to photocurrent ratio of α P in the mid x 10

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Cross-track Infrared Sounder (CrIS) is a Fourier Transform interferometer-based sensor used to measure earth radiance at high spectral resolution and low spatial resolution. Measured radiance data are analyzed by end users to provide pressure, temperature and moisture profiles of the atmosphere. The CrIS instrument contains Mercury-Cadmium-Telluride (MCT) photovoltaic (PV) detectors with spectral response in the SWIR, MWIR and LWIR ranges. The CrIS instrument requires large area detectors with state-of-the-art detector performance at temperatures attainable with passive cooling. In the case of the LWIR bands noise associated with the detectors limit the instrument performance. In this paper we describe a study of the noise characteristics of a sample of CrIS MCT PV detectors, emphasizing acquisition and validation of 1/f noise measurements for these devices. Interesting aspects of the 1/f noise dependence on bias-voltage and bias-current are noted. The results are analyzed further in a companion paper1 that emphasizes the relationship between leakage current mechanisms in the diodes and 1/f noise observed.

In 1854, Abraham Lincoln was retained to prepare a state legislative proposal to charter a homeopathic medical college in Chicago. This was a complex task in view of the deep-seated animosity between allopathic or orthodox medical practitioners and irregular healers. Homeopathy was regarded as a cult by the nascent American Medical Association. In addition, the poor reputation of medical education in the United States in general, further complicated the project. Lincoln and influential individuals in Illinois lobbied legislators and succeeded in securing the charter. Subsequently, the Hahnemann Homeopathic Medical College accepted its first class in 1860 and with its successors remained in existence for almost sixty-five years.

Relative Time Period: Follows the Early Eastern Woodland tradition in the lower Great Lakes and precedes the Northeast Late Woodland and Proto-Iroquois traditions.

The present investigation was undertaken in response to music therapists working in school settings for information relating to the availability of music therapy assessments and the feasibility of standardizing an assessment instrument for music therapists to use in school settings. Five research questions were identified, and the music therapy literature was surveyed to compile responses to those questions. Three different online data bases (ERIC, PsycINFO, and Article 1st) were used, covering articles published between 1980 and 1997. Individual hand searches were done of the Arts in Psychotherapy, Journal of Music Therapy, Journal of Research in Music Education, Journal of the International Association of Music for the Handicapped, Music Therapy and Music Therapy Perspectives. The questions and responses were as follows: 1. Which music-based assessment tools are being used with children with disabilities? Little commonality in assessment tools being used by music therapists and researchers was discovered. Of the total 41 studies, 20 (49%) reported using a "named" or "titled" assessment tool, and in the remaining 51% of studies, the authors reported using an untitled, and usually experimenter-designed, original assessment tool. 2. Have certain assessments been used in more than one study? Very limited replication of existing assessments was found. Of the 16 "named" assessments, only 3 were found to be used in more than one research study. 3. Are the actual assessments published along with the articles describing their use? Only 3 of the 20 studies using named assessments were published along with the journal article. Of the remaining 21 studies using original, experimenter-designed assessment tools, only 6 (28%) had the assessment instrument published with the article. 4. What is the primary purpose for using the assessment? Six primary purposes emerged from the review of the literature: to compare with data obtained from other assessment measures or from other populations (39%), as a baseline or pretest measure (29%), to determine eligibility for services or the receipt of treatment (12%), to determine the psychometric properties of the assessment (7%), suitability of the instrument for the given population (7%), and the identification of musical preferences (5%). 5. What are the musical or nonmusic elements being assessed? Musical elements were: music perception (37%), musical aptitude (29%), musical preferences (12%), and attention to/enjoyment of music (2%). Nonmusical behaviors/responses were: self-expression (10%), motor responses (10%), behavioral responses (7%), cognitive development (2%), and acts of communication (2%). 6. What subject populations are being assessed? Subject populations were: children with developmental disabilities/mental retardation (44%), children with autism (10%), children with hearing impairments (17%), "psychiatric" clients or emotionally disturbed (22%), individuals described as "handicapped" (5%), individuals with physical disabilities (2%), and a student with a speech impairment (2%). Nondisabled individuals were also included in 12 of the aforementioned studies.

Dense SnO2-based ceramics (relative density >95%) have been obtained by natural sintering at a moderate temperature (≤ 1300°C) with the help of a small amount of manganese. Further thermal treatments above 1500°C result in grain growth and transport of manganese toward the sample surface. If the ceramic is embedded inside alumina powder, the diffusion of Mn out of the sample and into alumina during such heat treatments leads to a manganese-free body (

For many terrestrial JR imaging applications, speed and sensitivity requirements can be met byseveral sensor technologies, including PtSi staring arrays, second generation scanned MCTarrays, InSb, and MCT staring arrays. However, for high quantum efficiency staring arrays,MCT and InSb in particular, much of the available signal remains unused because of well-fillrestrictions. In narrow spectral band imaging applications the available photon flux isdramatically lower and high quantum efficiency becomes critical. One such application isdetection and imaging of gases. High quantum efficiency arrays allow the use of narrow bandfilters centered on the absorption band of the gas, thus enhancing the ability of the imager todiscriminate between background and gas emission. Results of imaging studies performed on acamera with a narrow band filter for gas detection are presented and analyzed.Keywords: infrared, infrared imaging, infrared detectors, gas detection, indium antimonideAs infrared imaging detector development moves toward greater resolutions and wider fields ofview, applications other than simple JR imaging are becoming possible as well as moreintriguing. Uses of JR cameras to produce images of gases with emission (or absorption) lineswithin the passband of the camera have already found many applications. It is possible toproduce images of exhaled air from the lungs without great effort. The question to be consideredhere is how does one produce the highest possible gas detection capability by narrowing thespectral region that the JR camera sees to only the passband of the gas to be detected. Theobvious tradeoff here is that once the camera is optimized for use in only one narrow passband itcannot be used for other gases, unless they happen to be in the same passband. In order to boundthe problem two approaches have been used here. Images of a gas in the narrow passband inwhich it emits have been obtained. Noise and uniformity measurements taken for the cameraunder controlled conditions indicate the maximum sensitivity for gas detection that can beobtained with the camera as studied here. It should be pointed out that this study is preliminaryand in no way has optimization of the system for this purpose been performed.

The effects of hypercapnia on cerebral electrical activity and mitochondrial oxidative phosphorylation were studied in the anesthetized neonatal dog by using the electrocorticogram (ECoG) and 31P-magnetic resonance spectroscopy. Three levels of hypercapnia with arterial PCO2 values of approximately 70, 100, and 140 Torr reduced the intracellular pH of the brain from 7.11 to 6.99, 6.87, and 6.76, respectively. These levels of hypercapnia also reduced ADP concentration ([ADP]) from 21.5 to 18.1, 14.8, and 12.9 microM as well as the average ECoG power output by 20, 30, and 40%. A Michaelis-Menten relationship for the mitochondrial respiratory enzymes was fitted with [ADP] and the change in the average ECoG. The result suggests that mitochondrial respiration is regulated by [ADP] and that the in vivo Michaelis-Menten constant for ADP was 21 microM, a value close to the in vitro value. The mitochondrial maximal reaction velocity was reduced by only 10% during hypercapnia and showed no relationship with the degree of acidosis, suggesting that mitochondrial respiratory enzymes are not responsible for the inhibition of the brain electrical activity.

Previous models of reversible catch in echi- noid spines, as a property of muscle or of collagen, are briefly reviewed and discussed. This brief review offers a new interpretation of catch in primary spines of Eucidaris tribuloides, viewing the collagen and small muscles of the catch ligament working together as a variable-length ten- don. In the model presented, changes in ligament length when out of catch are accommodated by sliding of dis- continuous, interdigitating and cross-link-stabilized col- umns of collagen fibrils, the muscle layer external to the ligament effecting spine movement. Catch is viewed as a consequence of contraction of small muscles inserted on the collagen columns within the ligament. Ligament shortening tightens the profuse (ca. 30,000/mm2) and highly ordered collagen insertion loops within the ster- eoms of the spine base and test, and catch results from the multiplicative effect of these friction sites in series. New data are presented on novel structural cross-links between collagen fibrils. The cross-links stabilize the liga- ment columns. The central ligament in Eucidaris plays a purely passive mechanical role in maintaining the align- ment of the spine-test articulation. It contains no muscle and neither contracts nor undergoes catch; its insertions are simple, unlike the complex stereom insertions of the main ligament.

Il existe une relation directe entre des revenus faibles et une alimentation pauvre, car le manque de moyens financiers empechent les familles de manger a leur faim

This work is about the calculation of thermal conductivity of insulating building materials made from plant particles. To determine the type of raw materials, the particle sizes or the volume fractions of plant and binder, a tool dedicated to calculate the thermal conductivity of heterogeneous materials has been developped, using the discrete element method to generate the volume element and the finite element method to calculate the homogenized properties. A 3D optical scanner has been used to capture plant particle shapes and convert them into a cluster of discret elements. These aggregates are initially randomly distributed but without any overlap, and then fall down in a container due to the gravity force and collide with neighbour particles according to a velocity Verlet algorithm. Once the RVE is built, the geometry is exported in the open-source Salome-Meca platform to be meshed. The calculation of the effective thermal conductivity of the heterogeneous volume is then performed using a homogenization technique, based on an energy method. To validate the numerical tool, thermal conductivity measurements have been performed on sunflower pith aggregates and on packed beds of the same particles. The experimental values have been compared satisfactorily with a batch of numerical simulations.

Determining the relationship between light absorption and chromophore concentration in brain is complicated by photon scattering, which makes it difficult to determine pathlength. In the current study we apply newly developed phase modulation (PMS) and time-resolved (TRS) spectrometers to determine tissue scattering, pathlength and brain vascular hemoglobin saturation (BVH). PMS measurements were made from both frontal cortices of 36 adults using light guides separated by 4 cm and tightly placed against the forehead. TRS measurements were done with a 5 cm probe separation. For the PMS measurements, changes in phase shift were detected at 754 and 816 nm wavelengths. For TRS, the wavelength was 670 nm in all subjects, and some subjects had additional measurements made at a wavelength of 820 nm. Scattering and the extrapolated pathlength in the absence of hemoglobin were determined from the TRS data. This information was combined with the PMS data to determine BVH. The coefficient variation for the calculated saturation was only 0.04. This suggests both scattering and pathlength have significant intersubject variability and need to be explicitly determined for appropriate calculation of hemoglobin saturation.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The recent trend toward temporary inocclusion of proximal vessels prior to attempted aneurysm clipping places these patients at a risk for brain damage from focal ischemia secondary to inadequate collateral circulation. Though this risk is small with temporary occlusion of short duration, laboratory data and anecdotal clinical experience suggests this risk greatly increases with increasing duration of vessel occlusion. Because of this there has been renewed interest in attempting to increase the tolerance of the brain to these potential focal ischemic insults and several centers have begun to use large doses of intravenous anesthetics, most commonly thiopental or etomidate, toward this end.

The preparation for appropriate airway management in patients with actual or potential spinal injury begins with the recognition of patients at risk. In the traumatized patient, vertebral fractures are relatively common in patients with 1) head injury plus bleeding; 2) multiple injuries including fractures elsewhere; 3) brain injury and impaired consciousness; and 4) the intoxicated. Look for 1) alert patients who cannot move extremities on command, 2) unconscious patients who do not move in response to sternal pressure, 3) unconscious patients with a history of blunt trauma, 4) patients with penetrating injury to the neck or torso who cannot move on command or to sternal pressure, 5) patients with maxillofacial trauma, and 6) alert patients with neck or back pain (1). Hastings and Marks (2), emphasize the importance of neck pain or tenderness as signs of cervical spine injury. Patients can have significant bony or ligamental injury and vertebral column instability without neurologic damage. In addition, injury may occur to ligaments and instability may be present without bony injury.

Safety in anesthesia has improved because of better understanding of the pathophysiologic changes that occur in the anesthetized state, improved and more specific drugs, and improved monitoring of physiologic function. Blood pressure, electrocardiography (ECG), body temperature, pulse oximetry, and capnography are routine in virtually all operating rooms. Despite the innovations in monitoring and a plethora of new monitoring techniques, most monitors routinely available to the anesthesiologist do not measure adequacy of tissue perfusion or oxygenation despite the fact that prevention of ischemia at the organ level is a key role for the anesthesiologist. The only routine monitor that examines functional perfusion is the ECG where changes in the ST segment or arrhythmias may suggest inadequate myocardial perfusion.

Since first proposed by Demopoulos et al. (1,2) the hypothesis that free radicals were involved in the generation of post ischemic brain damage has remained provocative, but unproven. Four major lines of research attempting to demonstrate the validity of this hypothesis are in progress: 1) attempts to integrate the free radical hypothesis into changing concepts of ischemic brain damage, 2) the identification of free radicals in metabolically stressed tissue, 3) using free radical inhibitors in an attempt to protect the brain during various types of brain injury, and 4) expanding the concept of free radical damage to other types of nervous tissue damage such as spinal cord injury and vasospasm.

As the emphasis in infrared detector research shifts toward larger and more complicated arrays the amount of time spent on simple single-element and small arrays is decreasing. One set of applications where discrete detectors and arrays are still finding use is in satellites. In addition, scanned imaging arrays based on single element detectors and small arrays are still being manufactured. Discussion here is for small arrays and single element detectors. One of the aspects of detector operation that always needs to be addressed is amplification. Often detectors are attached to amplifiers through rather long leads. Such systems are subject to unwanted microphonic response as a result of the motion of the leads relative to each other or to the ground plane. This sort of microphonic response can many times be eliminated through careful wiring and routing techniques, however, in some severe environments it is not possible to eliminate all microphonic response. A commonly used solution to this problem is to hybridize the detector with a JFET front end to reduce the effective output resistance of the detector circuit relative to the amplifier input. The TIA in such configurations is completed off the focal plane at room temperature. This means that half the circuit is operating at cryogenic temperatures while the other part is operating at room temperature some distance away. Ideally it would be more convenient, if not better, to include the amplifier on the focal plane with the detector. (Of course this hybridization is necessary for large two-dimensional arrays.) Data have been acquired to show some of the limitations and opportunities for such an approach. Typical bipolar operational amplifiers (OP-27, OP-37, LM108) will not operate well at cryogenic temperatures. CMOS operational amplifiers generally will operate at cryogenic temperatures but suffer from high front-end voltage noise. The TLC2201 from Texas Instruments is a CMOS op-amp manufactured for low voltage noise. A discussion of its applicability to IR detector operation is presented herein.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

International audience; This paper examines the role of different factors in the microstructure of ceramic YBa2Cu3O7-δ with emphasis on its electrical response. In particular we discuss : 1. the effect of microstructural variations on jc and ρ300, 2. measurement of jc, 3. the presence of minor phases and carbonates, 4. oxygen uptake and microcracks, 5. plastic deformation and related structural defects.

Mitochondrial bioenergetics were investigated in newborn, neonatal and adult dog brains during normoxia and hypoxia. The ratio of the rate of ATP synthesis to the maximum synthesis rate (V/Vmax), phosphorylation potential, [ADP] and PCr/Pi, were used to evaluate age related mitochondrial hypoxic tolerance. These indicators were calculated from the phosphorus compounds measured by in vivo 31P MRS quantitatively using ATP as an internal reference. Indicators and substrates of mitochondrial function, V/Vmax, ADP, and Pi reached a peak value during the neonatal (3-21 days) period of development, suggesting that the oxidative metabolism of the neonate is more vulnerable to stress when compared to newborns and adults. Distinction among newborns and neonates became apparent during hypoxia. Newborns (0-2 days old) showed substantial tolerance by maintaining V/Vmax until exposure to severe hypoxia. Older neonates (3-21 days old) showed increases in V/Vmax, [Pi] and [ADP] under less than severe conditions of hypoxia. Adults exhibited low V/Vmax values even during exposure to severe hypoxia, further indicating that mitochondrial oxidative processes are more stable in adults than in newborns and neonates. This study provides evidence that newborns and adults are more capable of maintaining mitochondrial function under conditions of minimal to moderate hypoxia than 3-21 day old neonates.

The resolution of cytochrome and hemoglobin changes in in vivo rat and cat brains has required studies over wide wavelength ranges (580–1100 nm) with a novel spectroscopic technique using blood-free and blood-perfused brains. Tissue oxygen was varied from physiological levels to 0 and hematocrits were varied from normal to less than 1%. The experimental results were subjected to a multicomponent analysis using the Beer-Lambert law. At normal hematocrits, the oxygen saturation of hemoglobin in the brain was found to be 30–50% in rats and cats, indicating that the optical method responded primarily to the saturation of the venous ends of the capillary beds. With low hematocrits, both brains showed the absorption band of reduced cytochrome c , the iron component of cytochrome aa 3 , plus the absorption band of the oxidized copper component. In cat brains, the background absorption changed at all wavelengths. Thus, no isosbestic points were observed in the spectra. In rat brains, however, they were readily observed. The “overtones” of water absorption in the NIR region were found to be significant in the difference spectra of the cat brain, but not in the rat brain. Parallel absorbance changes in the heme and copper components of cytochrome aa 3 were obtained in rat and cat brains during the normoxic-hypoxic transition. The ratio of the iron absorbance at 605 nm to the copper absorbance at 830 nm is much smaller in both brains than the in vitro value due to the shorter path length of photon migration at the shorter wavelengths. The results indicate the validity of cytochrome measurements in the blood-free brain but confirm the extreme difficulty of quantitative measurements of cytochrome iron and copper in the blood-perfused brain.

The relationship between biochemical and physiological responses and tissue O2 during hypoxia was investigated in vivo in the dog brain by 31P nuclear magnetic resonance (NMR) spectroscopy. Our findings demonstrate how ATP synthesis in the brain can be maintained during hypoxia because of compensatory changes in NADH, ADP, and Pi. Eleven beagle dogs were anesthetized and mechanically ventilated, and a steady-state graded hypoxia was induced by decreasing the fraction of inspired O2 (FIO2) stepwise at 20-min intervals. Biochemical metabolites were measured using 31P-NMR and fluorescence spectroscopy. When sagittal sinus O2 partial pressure (PVO2) had decreased to 15 Torr, NADH increased by 30%, Pi increased by 50%, and phosphocreatine (PCr) decreased by 20%. In contrast, ATP remained constant. There was a 10% increase in ADP in dogs that maintained a steady temperature, but ADP decreased by as much as 30% in dogs in which body temperature decreased with the falling PVO2. PCr/Pi was logarithmically related to the phosphorylation potential during steady-state hypoxia. Compensation for the O2 lack is attributed to increases in ADP, Pi, and NADH as a result of the reciprocal relationship of the Michaelis-Menten equation. If the Michaelis-Menten constants (Km) of ADP, Pi, and O2 are the same as determined in vitro in mitochondria, the minimum brain cytosolic O2 capable of maintaining a steady-state ATP is near its Km (0.1 Torr) at a PVO2 of 7.5 Torr. At this critical O2 level, PCr/Pi is 0.9, intracellular pH is 6.75, phosphorylation potential is 38.5 mM-1, and the calculated maximum velocity of ATP formation by oxidative phosphorylation is 55% of normal.

Context.—Preemptive analgesia can decrease the sensitization of the central nervous system that would ordinarily amplify subsequent nociceptive input, but a clear demonstration of its clinical efficacy is necessary for it to become a routine component of acute pain therapy.Objective.—To determine the impact of preemptive epidural analgesia on postoperative pain and other clinically important outcome variables after radical retropubic prostatectomy.Design and Setting.—A block randomized double-blind clinical trial lasting 20 months at a single academic medical center.Patients.—A total of 100 generally healthy and neurologically intact patients scheduled for radical retropubic prostatectomy for the treatment of prostate cancer in whom an epidural catheter for treating postoperative pain was to be placed prior to the induction of general anesthesia.Interventions.—Epidural bupivacaine, epidural fentanyl, or no epidural drug was administered prior to induction of anesthesia and throughout the entire operation, followed by aggressive postoperative epidural analgesia for all patients.Main Outcome Measures.—Daily pain scores during hospitalization and pain scores obtained 3.5, 5.5, and 9.5 weeks after hospital discharge.Results.—The patients who received epidural fentanyl or bupivacaine prior to surgical incision (preemptive analgesia) experienced 33% less pain while hospitalized (P=.007). Pain scores in those receiving preemptive analgesia were significantly lower at 9.5 weeks (P=.02), but were not significantly different at 3.5 or 5.5 weeks. At 9.5 weeks, 32 (86%) of 37 patients receiving preemptive analgesia were pain-free compared with 9 (47%) of 19 control patients (P=.004). Patients receiving preemptive analgesia were more active 3.5 weeks after surgery (P=.01), but not at 5.5 or 9.5 weeks.Conclusions.—Even in the presence of aggressive postoperative pain management, preemptive epidural analgesia significantly decreases postoperative pain during hospitalization and long after discharge, and is associated with increased activity levels after discharge.

The principle of economy that emerged from the views of William of Occam, namely that where alternative hypotheses exist, the one involving the fewest assumptions is to be preferred, is still valid in science. Indeed, it was the application of "Occam's razor" that led us to propose a new model (1) to explain that mechanism of catch contraction in the primary spines of Eucidaris tribuloides--the model that I. C. Wilkie (2) considers inadequate through its failure to invoke collagen mutability.

A short-wave infrared (700–2500-nm) radiometer has been designed and built to calibrate and cross calibrate spherical-integrating sources used in the calibration of satellite sensors residing on NASA’s Earth Observing System platforms. We describe the design, predicted and measured performance, and calibration of the transfer radiometer.