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Case reports A 55-year-old woman presented with numbness and pain in both lower extremities. The pain was of sudden onset and of 4 months' duration. A nerve conduction study demonstrated a bilateral sensorimotor peripheral neuropathy with axonal and demyelinating features of a mild degree. Initial treatment with oral thiamine and topiramate had little efficacy and caused unacceptable side effects. A switch to 1500 mg bid levetiracetam plus nortriptyline resulted in a 60% improvement in pain symptoms. A 75-year-old man presented with numbness in both feet of 5 years' duration. The sensation of numbness had progressed to persistent pain, resulting in sleep disruption. The patient's use of oral thiamine did not lead to pain relief, but the addition of 500 mg levetiracetam once in the evening led to a complete resolution of his pain and to sleep improvement. A 67-year-old obese male was referred from a podiatrist with progressive dysfunction in both lower extremities that developed over a 1-year period. Walking more than a few steps resulted in sharp, shooting pain that at night disrupted sleep. A nerve conduction study demonstrated a severe bilateral sensorimotor peripheral neuropathy with axonal and demyelinating features. Treatment with 1000 mg levetiracetam bid resulted in complete absence of pain. Conclusions In these 3 case studies, levetiracetam was demonstrated to be an effective therapy in the treatment of neuropathic pain. It has the benefits of a low incidence of adverse events and an improvement in patients' sleep.

PRICE, M., P. MOSS, and S. RANCE. Effects of Sodium Bicarbonate Ingestion on Prolonged Intermittent Exercise. Med. Sci. Sports Exerc., Vol. 35, No. 8, pp. 1303–1308, 2003. Purpose: The aim of this study was to determine the effects of sodium bicarbonate ingestion on prolonged intermittent exercise and performance. Methods: Eight healthy male subjects (mean SD: age 25.4 6.4 yr, mass 70.9 5.1 kg, height 179 7 cm, V u O2max 4.21 0.51 L·min 1 ) volunteered for the study, which had received ethical approval. Subjects undertook two 30-min intermittent cycling trials (repeated 3-min blocks; 90 s at 40% V u O2max ,6 0 sa t 60% Vu O2max, 14-s maximal sprint, 16-s rest) after ingestion of either sodium bicarbonate (NaHCO3; 0.3 g·kg 1 ) or sodium chloride (NaCl; 0.045 g·kg 1 ). Expired air, blood lactate (BLa), bicarbonate (HCO3 ), and pH were measured at rest, 30 and 60 min postingestion, and during the 40% V u O2max component of exercise (4, 10, 16, and 29 min). Results: After ingestion, pH increased from rest to 7.46 0.03 and 7.40 0.01 for NaHCO3 and NaCl, respectively (main effect for time and trial; P 0.05). Values decreased at 15 min of exercise to 7.30 0.07 and 7.21 0.06, respectively, remaining at similar levels until the end of exercise. BLa peaked at 15 min (12.03 4.31 and 10.00 2.58 mmol·L 1 , for NaHCO3 and NaCl, respectively; P 0.05) remaining elevated until the end of exercise (P 0.05). Peak power expressed relative to sprint 1 demonstrated a significant main effect between trials ( P 0.05). Sprint 2 increased by 11.5 5% and 1.8 9.5% for NaHCO3 and NaCl, respectively. During NaHCO3, sprint 8 remained similar to sprint 1 (0.2 17%), whereas a decrease was observed during NaCl (10.0 16.0%). Conclusion: The results of this study suggest that ingestion of NaHCO3 improves sprint performance during prolonged intermittent cycling. Key Words: BLOOD LACTATE, PH, ALKALOSIS, PEAK POWER, PERFORMANCE, RPE

This study examined the effects of the level of spinal cord injury upon the thermoregulatory responses of wheelchair athletes during prolonged wheelchair exercise in warm conditions.Eight tetraplegic (TP), 10 high-level paraplegic (HP), and 10 low-level paraplegic (LP) athletes exercised for 60 min at 60% [OV0312]O(2peak) in a warm environment (31.5 +/- 1.7 degrees C, 42.9 +/- 8.0% relative humidity). Skin temperature and aural temperature were monitored.Aural temperature increased gradually during the exercise period by 1.1 +/- 0.3 and 1.4 +/- 0.5 degrees C for the HP and LP groups, with a more marked increase observed for the TP group (2.1 +/- 0.5 degrees C; P0.05). Upper-arm skin temperature was higher for the TP when compared with the HP and LP between 30 and 60 min (P0.05). Back skin temperature was higher for the TP when compared with the HP and LP between 45 and 60 min (P0.05). No differences were noted between groups for the thigh or calf skin temperatures. During recovery, skin temperature remained elevated for the TP group when compared with the HP and LP groups (P0.05). Heat storage was greatest for the TP athletes at the end of exercise and remained elevated throughout recovery (P0.05).All athletes completed the exercise task even though the gradual increase in aural temperature observed for the HP and LP groups suggests a degree of thermal imbalance. However, this was much less than observed for TP athletes, who demonstrated a much greater imbalance in temperature regulation. Increasing the exercise or environmental strain may result in the thermoregulatory responses of athletes with a spinal cord injury being compromised.

Both the Mie scattering and polarimetric transport models indicate that, in the LWIR, the atmospheric effect on the transport of right-hand circularly polarized signals and left-hand circularly polarized signals is identical. In the LWIR, the observed normalized circular polarization anisotropy, S3/SO, of a signal should not require any atmospheric corrections. Because natural LWIR light in not circularly polarized, only an active system will be able to exploit this finding. Both the Mie scattering and polarimetric transport models indicate that, in the LWIR, the atmospheric effect on the transport of the two orthogonal components of linearly polarized signals should be significantly different. In the LWIR both the observed degree of lineal polarization and the observed normalized linear polarization anisotropy Si/SO of a signal should require atmospheric corrections.

This monograph examines the ability of the United States Army to shape the battlefield without the use of conventional landmines. The United States must determine alternatives to conducting warfare without the use of landmines. The humanitarian crisis landmines create calls for this and current and future technologies make it possible. Weapons that cannot discriminate between combatant and non-combatant will lose their legitimacy in the future battlespace. This study traces the evolution of landmines and their purposes. It then reviews current Amen can, British, and Canadian counter-mobility doctrine in order to establish a foundation to build upon. With this solid foundation of the past and present, the study then progresses to address how the United States can shape the future battlespace. This study offers alternatives to conventional landmines through technology, doctrine, and training. Through their evolution, landmines have become an effective force enabler in the conduct of land warfare, but in recent times their usefulness has diminished. Situational and scatterable landmines have increased importance in the changing environment. The evolution of the humanitarian crisis from their use supports a complete ban on the use of conventional landmines. The costs associated with landmine use are mind numbing. Medical and rehabilitation costs alone exceed 5750 million. The effects of wars long past continue to plague ravished nations. With current dc-mining efforts, the estimate by the Vietnam Veterans of America Foundation (VVAF) to remove the existing landmines exceeds forty years. Based on this, the evidence supports a total ban on the use of conventional landmines, both anti-personnel and anti-tank.

The aim of this study was to assess the influence of three imposed crank rates on the attainment of peak oxygen consumption (VO2peak) and other physiological responses during incremental arm crank ergometry. Twenty physically active, although non-specifically trained, males volunteered for the study. They completed an exercise protocol using an electrically braked arm ergometer (Lode Angio, Groningen, Netherlands) at crank rates of 60, 70 and 80 rev x min(-1). The order of tests was randomized and they were separated by at least 2 days. Peak VO2 was significantly higher (P0.05) at 70 and 80 rev x min(-1) than at 60 rev x min(-1). Peak ventilation volume increased as a function of crank rate and was higher (P0.05) at 80 than at 60 rev x min(-1). Peak heart rate was higher (P0.05) at 70 and 80 rev x min(-1) than at 60 rev x min(-1). Furthermore, 70 and 80 rev x min(-1) resulted in an extended test time compared with 60 rev x min(-1). The greater physiological responses observed during the tests at the two faster crank rates might have been the result of a postponement of acute localized neuromuscular fatigue, allowing for more work to be completed. We recommend, therefore, that an imposed crank rate between 70 and 80 rev x min(-1) should be used to elicit VO2peak and other physiological responses in arm crank ergometry.

Seven wheelchair athletes participated in this study. On separate occasions all athletes performed 60 min of arm crank ergometry and wheelchair ergometry at 60% of the ergometer specific VO2peak in cool conditions (21.5+/-1.3 degrees C; 54.2+/-6.3% relative humidity, 21.2+/-1.9 degrees C; 55.5+/-11.9% relative humidity, respectively). The order of testing was randomised. Aural and skin temperatures were continually measured throughout the 60 min test. Expired air was collected at 5, 15, 30, 45, and 60 min during the exercise period. Oxygen consumption was similar for both trials (1.09+/-0.21 and 1.16+/-0.331 x min-(-1), for the ACE and WCE trials, respectively). Heat storage was calculated at these time-points. Aural temperature was elevated from rest between 25 to 45 min of wheelchair ergometry (0.5+/-0.3 degrees C; P < 0.05) when compared to between 20 min of exercise and 5 min of recovery (0.6+/-0.3 degrees C; P

Purpose: To design and investigate the imaging and dosimetric capabilities of a novel, CT/MR‐suitable, anatomically adaptive, shielded cervical HDR/PDR brachytherapy applicator. Method and Materials: An applicator was constructed featuring an inter‐colpostat shield that can translate/rotate about the colpostat's long‐axis. Artifact‐free CTimaging was achieved using a “step‐and‐shoot” technique; pausing the scanner midway through the scan and moving the shield out of the beam's path. Artifact‐free MRIimaging was achieved by utilizing MRI‐compatible ovoid components and pulse‐sequences that minimize susceptibility artifacts. The applicator's imaging capabilities were demonstrated acquiring images using phantoms that positioned the novel and Fletcher‐Williamson ICBT applicators in clinically‐applicable geometries for both modalities. Artifacts were qualitatively compared. To evaluate any dosimetric advantages, Monte‐Carlo models of the novel and FW applicators were first validated. Anatomies of patients that have undergone ICBT for cervical disease were modeled using Monte‐Carlo and spatially registered with models of both applicators using SolidWorks; a CAD software suite. Equivalent, clinically‐applicable 192 Ir loadings were simulated for both applicators using Monte‐Carlo techniques. The novel applicator shield's rotation and translation was adjusted for each dwell position in order to minimize dose to the rectum and superimposed for comparison to equivalent FW treatments. Rectal dose (rate and absolute) volume histograms were determined for both applicators and compared. Results: Using a “step‐and‐shoot” CT scanning method and MR compliant materials and optimal pulse‐sequences, images of the novel applicator were artifact‐free using both modalities. Additionally, for the patient case presented, there is a 26% and 13% reduction of d90 and d50, respectively, and a 13% reduction in overall absolute dose to the rectum when compared to equivalent Fletcher‐Williamson ICBT treatments. Conclusion: A novel ICBT applicator can be imaged using CT/MR without artifact and reduce dose to the rectum compared to the current state‐of‐the‐art, FW ICBT applicator. Conflict‐of‐Interest: Work partially supported by Nucletron Corp.

Purpose: To calculate the dose distribution around a high dose‐rate (HDR) 192Ir brachytherapysource in water by a multi‐group discrete ordinates code and compare with a benchmarked Monte Carlo calculated dose distribution. Methods and Materials: The multi‐group discrete ordinates code, Attila™ version 5.0.2 (Transpire Inc., Gig Harbor, WA) was used to calculate the dose distribution around the Nucletron microSelectron HDR source (Nucletron B.V., Veenendaal, The Netherlands). MCNPX 2.4.k was used to benchmark the deterministic calculations. The source was constructed with Solidworks (Solidworks Corp., Concord, MA), a mechanical design software. The constructed geometry of the source,dose scoring plane and sphere were exported in Parasolid® file format so that it could be imported into Attila. MCNPX 2.4.k was used to compute the Monte Carlodose distribution. 50 million histories were simulated resulting in standard errors of the mean of less than 5% at a point 7 cm from the center of the source. The source geometry was identical to that of the Attila run except for minor differences in modeling the source due to limitations of the MCNPX code. Dose rate matrices were exported from both codes and imported into an in‐house data analysissoftware. This software overlaid the matrices and quantified the percent dose difference and distance‐to‐agreement for all points in the matrices. The number of points passing a 2%/2mm criterion were reported. Results: Attila calculated dose to within ±2% or 2mm for 99% of the points. The Attila calculations required approximately 38 minutes of CPU versus 568 minutes for MCNPX on the same CPU. Conclusions: The Attila multi‐group discrete ordinates code accurately calculated the anisotropy from the microselectron HDR source. Attila accurately calculated dose in an efficient manner.

The purpose of this study was to determine (1) the repeatability of a currently recommended protocol for determination of VO2 peak during upper body exercise involving a crank rate of 60 rev min-1 (Hale et al. 1988), (2) whether employing a higher crank rate (70 rev min-1) elicits higher VO2 peak values; (3) whether including an additional exercise stage 5 min after volitional exhaustion would elicit higher VO2 peak values. Twenty subjects (mean +/- SD) age, height and body mass were 22.8 +/- 1.8 years, 176 +/- 5.0 cm and 77.5 +/- 4.0 kg, respectively) visited the laboratory on three separate occasions. Subjects performed a different test to determine upper body VO2 peak on each visit. The tests were continuous and incremental in nature and were performed on a Monark cycle ergometer (Model 814E) adapted for arm exercise. Test 1 required subjects to exercise at a crank rate of 60 rev min-1 (60RPM-1). Test 2 was identical to test 1 (60RPM-2) but after 5 min recovery from the test subjects performed a further exercise stage (60RPM-F). Test 3 employed a crank rate of 70 rev min-1 (70RPM). Five minutes after volitional exhaustion a further exercise stage was performed (70RPM-F). The levels of agreement for the 60 rev min-1 protocol were +/-0.50 1 min-1. All VO2 peak values achieved were within these limits. However, a higher VO2 peak was achieved by employing a crank rate of 70 rev min-1 (p0.05). The VO2 peak achieved for 60RPM-F was similar to 60RPM whereas the VO2 peak for 70RPM-F tended to be less than that for 70RPM (p = 0.064). The results of this study suggest that the 60 rev min-1 protocol can reliably determine VO2 peak, however it would appear to be more appropriate to employ a 70 rev min-1 protocol as higher values were attained.

The thermoregulatory responses of ten paraplegic (PA; T3/4-L4) and nine able-bodied (AB) upper body trained athletes were examined at rest and during prolonged arm-cranking exercise and passive recovery. Exercise was performed for 90 min at 80% peak heart rate, and at 21.5 (1.7) degrees C and 47.0 (7.8)% relative humidity on a Monark cycle ergometer (Ergomedic 814E) adapted for arm exercise. Mean peak oxygen uptake values for the PA and AB athlete groups were 2.12 (0.41) min(-1) and 3.19 (0.38) l x min(-1), respectively (P

Head injuries in skiing have been a cause for concern due to the high incidence of injury particularly in young people. Furthermore, head trauma is the leading cause of death overall in skiing. Encouraging individuals to wear helmets can be problematic, especially since helmets are not compulsory in many resorts, are an additional expense and not seen as a necessity. The aim was (1) To synthesise information regarding head injuries and helmet use in young people. (2) To make a recommendation for the appropriateness of helmets use. Following ethical approval and informed consent, 101 responses were gathered from an electronic survey. This was administered to secondary schools across England which organise ski trips to identify helmet use. Electronic databases were searched for articles dating back 15 years and synthesised with grey literature as a narrative review to inform current concepts on helmet use in young people. The pooled narrative findings from literature suggest helmet use has reduced the number and severity of injuries to the head. The overall consensus is for helmets to be recommended, especially in the young. From 101 secondary schools surveyed, 96% of teachers expect young people to wear helmets whilst skiing. Discussion: The compulsory wearing of helmets in several resorts has helped to increase the awareness and importance of helmet use. A potential impact on not wearing a helmet is the concern that holiday insurance could be invalidated if injured. One British insurer now stipulates for the mandatory wearing of helmets within their policy. Findings show helmet use has been associated with a reduced risk of head injuries and the International Ski Federation recommends that all skiers regardless of ability and age use helmets. Ski helmets should be included within the ski rental package to decrease financial barriers.

A multispectral normalization processing system has been developed to produce percent reflectance maps from multispectral imagery (MSI) in the .4 to 2.5 micron wavelength range. It is adaptive to multiple spatial resolutions, supporting resolutions in the .25 meter to 30 meter range. The normalization process takes advantage of known naturally occurring and man-made materials in the image to remove the effects of atmospheric haze and sensor gain contributions for each multispectral band. The output product is a percent reflectance map for each multispectral band. Although the normalization technique is well known, the MSI normalization system (MSINS) provides a simple, adaptive, robust graphical user interface for normalizing multispectral imagery from various sensor platforms. Over 130 different surface material spectra have been collected from reputable sources in literature and other spectral material libraries and installed in the MSINS Materials Spectral Information Database (MSID). The MSID has been designed to allow the addition of new material spectra into the system via a menu interface. A neural-net-based region grower has been developed to minimize user interaction and increase the robustness and repeatability of the normalization. New multispectral sensor platforms can be introduced into the system quickly via a menu interface. The current system was developed and tested using Landsat Thematic Mapper, Erim M7 Mapper, Positive Systems ADAR 5500, and ITRES casi multispectral imagery.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Purpose: To evaluate the potential for an implantable dosimeter to be also used as an internal fiducial maker. Additionally, to evaluate the synergy of the dosimeter/fiducial capabilities. Method and Materials: Two implantable MOSFETdetectors (DVS®, Sicel Technologies, Inc.) were placed inside an acrylic pelvic phantom for which a wedged‐field photon plan and an eight‐field prostate treatment plan were developed. For each plan, conditions were simulated so that detectors were in their correct positions or slightly displaced to represent patient setup error and/or organ motion. Doses measured by the two detectors after irradiation were compared to those calculated by the treatment planning software. Additionally, using localization software (MarkerVision, Varian MedicalSystems) and kilovoltage images of each setup, the displacement of the detectors from their correct locations was calculated and compared to the induced physical displacement. Results: For all alignments and detector positions, measured and calculated doses showed an average disagreement of 2.7%. The detectors were easily visualized in AP and lateral radiographs, and the induced detector displacements were typically recognized by the localization software within 0.1 cm, and were recognized within 0.16 cm at worst. The relationship between the geometric displacement and measured dose was dependent on the positioning of the dosimeter and dose gradients. If the detector was placed in a uniform dose region then geometric displacements did not induce any dosimetric discrepancies. Alternately, if the detector was placed in a strong dose gradient then even high geometric accuracy resulted in dosimetric discrepancies. Conclusion: The implantable detector functioned well as both an internal dosimeter and as an internal fiducial marker and thus may be useful as a clinical tool to localize the target volume and verify dose delivery in vivo. Conflict of Interest: Research was supported by a grant from Varian MedicalSystems.

Purpose: To demonstrate the capability of a prototype, high‐dose‐rate/pulsed‐dose‐rate (HDR/PDR) intracavitary brachytherapy cervical applicator to be (a) imaged using computed tomography(CT) with minimal artifacts as compared to current, clinically‐utilized applicators and (b) deliver dose to a simulated disease plane that is at least equivalent to that delivered by the FW applicator while delivering less dose to multiple, simulated rectal planes for equivalent loadings. Capability (b) demonstrates the prototype applicator's ability to adapt to varying patient anatomies utilizing a remotely adjustable shield contained within the colpostat. Method and Materials:CTimage sets were acquired of the Fletcher‐Suite‐Delclos (FSD), Fletcher‐Williamson (FW), and prototype applicators (utilizing a step‐and‐shoot technique) and artifacts generated by each were compared qualitatively. Images were acquired of the applicators positioned parallel to the table and in positions that simulated applicator placement during treatment. Using film validated MCNPXMonte Carlo(MC) models of the prototype and FW applicators, dose comparisons (min, max, average, and dose‐surface histograms) were made in simulated disease (1cm medial to colpostat) and multiple rectal (1cm distal and 0, 0.5, and 1cm medial to the colpostat) planes. Results: Preliminary results indicate that the prototype applicator is CT‐friendly; qualitatively minimizing anatomy‐obscuring artifacts compared to equivalent FW and FSD image sets. Additionally, the prototype applicator is able to deliver comparable dose levels (within +/− 5%) to a simulated disease plane while reducing dose (32% average) to varying simulated rectal planes when compared to equivalent FW treatments. Conclusion: The prototype applicator is able to be CTimaged with minimal artifacts and substantially reduce dose delivered to the rectum while maintaining dose delivered to disease when compared to current ICBT technologies. Currently, the model is being extended to include two prototype applicators and a 15° tandem so that dose‐volume histograms can be generated using specific‐patient cases of varying anatomical geometries.

Purpose: 1) To validate a Monte Carlo (MC) model of the Ir‐192 pulsed‐dose rate (PDR) source inside the Fletcher‐Williamson (FW) ovoid using radiochromic film measurements. 2) To compare the FW dose distributions in water to those of Cs‐137 low‐dose rate (LDR) pellet inside the Selectron Fletcher‐Suit‐Delclos (FSD) ovoid. Method and Materials: Detailed mechanical drawings of the FW colpostat were obtained from the vendor. MCNPX 2.5e MC code was used to model the small right FW ovoid and an Ir‐192 source (mHDR v2) centered within the ovoid. MC models of actual and virtual Ir‐192 source in air were also run to derive the conversion from contained to apparent activity. MD‐55 radiochromic film was placed in a polystyrene phantom at a plane parallel to and displaced medially 2.0 cm from the long axis of the colpostat. To compare with the FSD ovoid, MC runs in a 30 cm water sphere were run for common ovoid loadings of 5, 10, 15, and 20 mgRaeq. Results:MCNPX calculated dose relative to film measurements is within ±2% or 2mm distance‐to‐agreement for 92% of the dose grid. For the FW simulations in water, the overall shapes were found to be similar in regions away from the shields to those obtained for the FSD ovoid; however, large but localized deviations were found in high dose‐gradient regions close to the rectal and bladder shields, mainly due to differences in source and shields geometry. Conclusion: The dose distributions predicted by MCNPX are in good agreement with the film results. Dose‐rate atlases calculated in clinically‐relevant 2D planes around the FW and FSD ovoids provide information to aid in the transfer of current LDR intracavitary brachytherapy practice to that using PDR for treatment of gynecological cancers.Conflict of Interest: Partial support by Nucletron Corporation.

Dopamine is a neurotransmitter found in the retina. Delays in the visual evoked responses and abnormalities in contrast sensitivity occur in patients with Parkinson's disease. Improvement in the P100 has followed L-dopa therapy. Suspected abnormalities at the retinal level in Parkinson's disease are observed in reductions in photopic, scotopic, and pattern-derived electroretinograms. We studied 35 patients with Parkinson's disease and 26 controls of comparable age and visual acuities using visual evoked responses, color vision, and contrast sensitivity testing. Contrast sensitivity thresholds were significantly different at most frequencies tested, using both stationary and temporally modulated sinusoidal gratings. The total error score of the Farnsworth-Munsell 100 Hue Test revealed significant differences between the patients and controls. The contrast thresholds derived from certain spatial frequencies and the total error in color score were significantly related to the duration of disease. A stepwise discriminant analysis correctly identified 94% of the patients and 94% of the controls. The significant error in chromatic discrimination observed in Parkinson's disease patients may be due to altered intraretinal dopaminergic synaptic activity in these patients.

New measurements of the equivalent widths of the 4.0 S(0) and S(1) H2 quadrupole lines in the Uranian spectrum have been obtained using high dispersion (4.12 A/mm) image-tube spectrography. The measured equivalent widths are 62 plus or minus 19 mA and 58 plus or minus 13 mA for the S(0) and S(1) lines, respectively. Curve-of-growth analysis in terms of a reflecting layer model yields an H2 column density of 780 (+940 or -330) km amagat and a temperature of 78 (+80 or -24) K. Interpretation using a semiinfinite, homogeneous, isotropically scattering model for line formation yields a scattering mean free path at 6400 A of 550 plus or minus 250 km amagat. Quoted errors for both the H2 column density and the scattering mean free path include the effect of uncertainty in the choice of atmospheric temperature. The results are discussed in terms of current models for the Uranian atmosphere.

The pattern electroretinogram (PERG) may reflect ganglion cell or inner retinal layer activity. The most sensitive spatial and temporal variables for testing patients with glaucoma have not yet been identified. Fifty-two glaucoma suspects, 51 glaucoma patients, and 28 normal subjects were studied with the PERG and VEP, using three repetition rates and three spatial frequencies. Fast Fourier transforms were calculated at each spatial frequency and reversal rate. An analysis of variance revealed that normals could be differentiated from ocular hypertension and glaucoma patients using the amplitude of the PERG (second and fourth harmonic). Abnormalities in phase of the PERG between groups were also detected. A discriminant analysis of all amplitude and phase data revealed that the phase shift of the response of the second harmonic at 11 alternations/s (15-min checks) and at 5.5 alternations/s (15-min checks) correctly identified 81% of the normal and 75% of the glaucoma patients. The phase shift determinations of the VEP revealed significant abnormalities using 2 and 1/2 standard deviation confidence limits. There was significant overlap in the pattern ERG amplitude and phase shift in all three groups.

Indirect solar illumination of Saturn's ring via scattering from the ball of the planet provides a new ground-based observational technique for studying the single scattering albedo and phase function of the individual particles. Information concerning optical thickness may also be obtained. Essentially complete phase angle coverage can be achieved by studying the variation with azimuth of the indirect contribution to the surface brightness of the ring. Initial application of the technique is reported. The indirect contribution to the radiation scattered from the ring has been marginally detected by electronographic areal photometry. The results have been interpreted using simple scattering models. The photometric accuracy was insufficient to permit investigation of departures from isotropic scattering. But high single scattering albedos, and an essentially opaque ring, are indicated.

Results are presented for pinhole and slit narrowband photoelectric area-scanning photometry of the Uranus disk at eight central wavelengths ranging from 5600 to 7500 A. The observations were undertaken to detect limb brightening on the planet and to study the nature of its disk profile as a function of geometrical albedo. A coarse analysis of the results shows that the disk must exhibit limb brightening in the two CH4 bands at 6190 and 7300 A relative to all other wavebands investigated. Except for the two CH4 bands, the shapes and widths of the images are found to be essentially identical; point-spread-function data for all wavebands indicate no significant variation in the representative Gaussian l/e width with wavelength. A fine analysis of the data reveals absolute limb brightening in the 7300-A CH4 band and absolute limb darkening in the adjacent wavebands. These results are shown to be consistent with the hypothesis that clouds are absent from the visible atmosphere of Uranus.

Infrared (10 and 20 microns) thermal emission data for Saturn's rings are discussed in terms of simple isothermal radiative transfer models of finite optical thickness. Recent brightness temperature measurements, corresponding to essentially maximum ring tilt, indicate that optical single scattering albedos less than 0.75 are required to provide sufficient heating of the ring material. Reconciliation with analyses of the optical scattering properties of the ring requires the backscattering efficiency to be even higher than for a macroscopic sphere. Historical brightness temperature measurements are used to show that no unique isothermal ring model exists. Instead, a temperature gradient perpendicular to the ring plane appears to be present.

Quantitative predictions of the diffuse reflection and transmission properties of Saturn's rings, relevant to the September 1979 Pioneer 11 flyby, are presented. Predictions are based on an elementary anisotropic scattering model. Interparticle separations are considered to be sufficiently large that mutual shadowing is negligible. Likely ranges in both the single scattering albedo and perpendicular optical thickness of the ring are considered. Situations of pronounced back-scattering and of isotropic scattering are treated individually. Spacecraft measurement of the radiation suffering diffuse scattering by the ring can provide a useful test of the basic ring model.

Further analysis of visual (V) wavelength photometric function data for Saturn's ring is presented. Evidence indicating both that primary scattering dominates, and that mutual shadowing is an irrelevant concept, is reviewed. Simple anisotropic scattering radiative transfer models are used to define the probable ranges in the single scattering albedo, and in the general shape of the scattering phase function of the individual particles. Limitations on the mean perpendicular optical thickness of the ring are also obtained. Results indicate that the ring particles are highly efficient back-scatterers of visual radiation. Macroscopic particles account for the basic shape of the scattering phase function. Based on an infinite optical thickness for the ring, a minimum single scattering albedo ≈0.75 is found. Use of conservative scattering leads to a minimum optical thickness ≈0.7. The analysis is consistent with the ring particles being centimeter-size pieces of ice.

Orthogonal narrow-band (100 A) photoelectric slit scan photometry of Uranus has been used to infer the basic two-dimensional structure of the disk within the 7300-A methane band. Numerical image reconstruction and restoration techniques have been applied to quantitatively estimate the degrees of polar and limb brightening on the planet. Through partial removal of atmospheric smearing, an effective spatial resolution of approximately 0.9 arcsec has been achieved. Peak polar, limb, and central intensities on the disk are in the respective proportions 3:2:1. In addition, the bright polar feature is displaced from the geometric pole towards the equator of the planet.

Pattern evoked electroretinograms (PERG), diffuse flash electroretinograms (ERG) and visual evoked potentials were studied in patients with unilateral optic nerve disease. Patients with Snellen acuities of less than 6/30 did not have recordable PERGs in their affected eye, whereas their diffuse flash ERGs were normal. The VEPs were correspondingly reduced or absent when recorded from the poorer seeing eyes. A second group of patients with Snellen acuity between 6/6 and 6/30 in the involved eye showed reductions in the mean PERG amplitude of the affected as compared with the normal eyes. All affected eyes showed an abnormal contrast threshold measured with the PERG amplitude. Such results underscore the diagnostic value of the PERG in detecting even mildly affected cases of optic nerve disease.

An error in the Hayes and Belton (1977) , Icarus 32, 383–401) estimate of the rotation period of Neptune is corrected. If Neptune exhibits the same degree of limb darkening as Uranus near 4900 A, the rotation period is 15.4 ± 3 hr. This value is compatible with a recent spectroscopic determination of Munch and Hippelein (1979) who find a period of 11.2−1.2+1.8 hr. However, if, as indirect evidence suggests, the law of darkening on Neptune at these wavelengths is less pronounced than on Uranus, then the above estimates may need to be lengthened by several hours. Recent photometric data are independently analyzed and are found to admit several possible periods, none of which can be confidently assumed to be correct. The period of Neptune most probably falls somewhere in the range 15–20 hr. The Hayes-Belton estimate of the period of Uranus is essentially unaffected by the above-mentioned error and remains at 24 ± 4 hr. All observers agree that the rotation period of Uranus is longer than that of Neptune.

A semiquantitative analysis of clearing in the 1971 great dust storm on Mars is presented as a function of time and altitude, using Mariner 9 orange- and visual-light photos. Steady settling of dust approximately accounts for the decline of the storm after Dec. 22, 1971. Continuous settling cannot be invoked prior to that date; injection of dust into the atmosphere, i.e., a storm resurgence, occurred in mid-December 1971. Theoretical models of optical depth vs time are developed for various distributions of particles in the atmosphere. By interpreting settling in terms of Stokes' law, estimates of the maximum radii of dust particles throughout the atmosphere have been obtained. Models which best account for the dust-storm decline indicate particles less than 5 microns in diameter high in the atmosphere, with a concentration of larger particles near the ground in the lowest parts of Mars.

Measurements of limb brightening on the Uranus disk within the lambda 7300 A CH4 band are interpreted using an elementary inhomogeneous radiative transfer model to describe the atmosphere. A two layer model which consists of a finite, optically thin, region of conservatively scattering particles overlying a semi-infinite clear H2-CH4 atmosphere satisfactorily explains the observations. The maximum optical thickness of the upper layer appears to lie in the range 0.1 to 0.2. The CH4/H2 mixing ratio in the lower layer is larger than the corresponding solar value by a factor on the order of three or greater. The results are discussed briefly in terms of current models of the Uranus atmosphere.

A general Monte Carlo relaxation method has been formulated for the computation of physically self-consistent model stellar atmospheres. The local physical state is obtained by solving simultaneously the equations of statistical equilibrium for the atomic and ionic level populations, the kinetic energy balance equation for the electron gas to obtain the electron temperature, and the equation of radiative transfer. Anisotropic Thomson scattering is included in the equation of transfer and radiation pressure effects are included in the hydrostatic equation. The constraints of hydrostatic and radiative equilibrium are enforced. Local thermodynamic equilibrium (L.T.E.) is assumed as a boundary condition deep in the atmosphere. Elsewhere in the atmosphere L.T.E. is not assumed.

Further simultaneous two-color photoelectric photometry of Ganymede was carried out at blue (4500 A) and yellow (5790 A) wavelengths during its eclipse by Jupiter on Mar. 10, 1971. In both colors, the shape of the ingress light curve was again reliably determined for extinctions up to 9 mag. Neither curve showed any evidence of a refraction tail. The observations have been interpreted in terms of the local optical transmission properties of the Jovian atmosphere. At gas number densities of about 5 x 10 to the 18th power per cu cm the maximum photon scattering mean free path at visual wavelengths was 47 km atm. Evidence indicates that neither a simple reflecting-layer model or a semiinfinite homogeneous scattering model provides an adequate physical description of the atmosphere.

Simultaneous two-color photometry of Ganymede was carried out at blue (γ 4500 A) and yellow (γ 5790 A) wavelengths during its eclipse by Jupiter on 1970 March 24. In both colors, the shape of the ingress light curve was reliably determined for extinctions up to 9 magnitudes using an area-scanning photometer. Both curves showed a refraction tail, caused by sunlight passing through the Jovian atmosphere, after the satellite had entered the geometrical shadow of the planet. The observations have been used to infer the basic optical scattering properties of the atmosphere. At gas number densities near 5 × 10 18 cm −3 , the Jovian atmosphere contains a haze of aerosol particles whose radii are at least 1 μ. Their maximum permissible number density in those regions of the atmosphere is 0.2 cm −3 . At both blue and yellow wavelengths the amount of gas in a scattering mean free path is estimated to be 140 km atm. The observations give an optimum photometric radius for Ganymede of 2200 (±100) km.

We tested 47 eyes in 47 patients (ten normal subjects, 15 with suspected glaucoma, and 22 with glaucoma) with the Pickford-Nicholson anomaloscope to assess the retinal nerve fiber layer and measure color vision. The 47 subjects were randomly selected from a group of 132 for whom Farnsworth-Munsell 100-hue color error scores were known. The yellow-blue and green-blue anomaloscopic matching ranges correlated significantly with diffuse retinal nerve fiber loss. There was no correlation with localized retinal nerve fiber loss.

Videotapes were analyzed to assess sperm motility and morphology in the semen of 5 fertile donors and 20 infertile patients. The slow motion playback control of the video recorder allowed simultaneous assessment of the motility and morphology of individual sperm cells. Similar values were obtained with this method for living sperm cells and for sperm on fixed, Papanicolaou-stained seminal smears. Spermatozoa with abnormal morphology more often were immotile or weakly motile than were the normal sperm in the same ejaculates. Normal oval sperm in the semen of infertile men were less likely to be motile and tended to swim more slowly than did morphologically normal sperm in the semen of fertile men.

A case of coccidioidomycosis of the prostate is presented, adding another case to the 6 antemortem cases in the English literature since 1940.

We measured a number of structural characteristics of the optic nerve head and retina in 52 glaucoma suspects, 51 glaucoma patients, and 28 normal eyes. In all of the patients, a number of psychophysical functions were recorded and evoked cortical potentials and pattern electroretinography were obtained. The correlations between these structural and functional parameters were established by multiple regression. Diffuse structural changes in the optic nerve head and retina were related to differential light threshold and color that measure diffuse psychophysical disturbances. Localized changes in the retinal nerve fibers and the vertical cup/disk ratio related to the "corrected loss variance," which is an index measuring localized psychophysical changes.

Sprint tests are frequently used to evaluate between-subject differences and can provide a valuable insight into performance capacity. The present study determined the reproducibility of peak and mean power output during upper-body sprints. After familiarization 25 men (mean [+/- SD] age 29 [6] years, body mass 82.8 [12.7] kg and height 1.76 [0.05] m) completed 2 20-second upper-body sprint tests using an adapted cycle ergometer. Mean (+/- SD) values of all power (uncorrected and corrected) measurements achieved during the 2 tests were checked for systematic bias using separate paired t-tests. Test-retest reproducibility was examined using coefficients of variation and single-measure intraclass correlation coefficients, as well as an assessment of the typical (random) error and the 95% limits of agreement. The value of corrected peak power (628 [167] W) was higher (p0.05) compared with the uncorrected value (509 [109] W). Values of corrected (465 [95] W) and uncorrected (444 [87] W) mean power were similar (p0.05). The mean bias value for all power parameters equated to less than +/-1% of the absolute values of power measured. Intraclass correlation coefficients for all data sets ranged from 0.97 to 0.98. Coefficients of variation for uncorrected and corrected values of peak power were 2.8 and 4.5%, while corresponding values for mean power were 2.9 and 3.2%, respectively. The reproducibility of all power indices was below 5%. The results of this study indicate that both uncorrected and corrected measurements of peak power output and mean power output can be used to assess performance during sprint arm ergometry.

INTRODUCTION: Previous research has indicated that carrying a backpack elicits an increase in postural sway during quiet standing (Heller et al. 2009) and stride-to-stride gait variability during walking (Qu and Yeo, 2011). Despite these initial enquires into the effects of carrying external loads on postural stability, little research has examined the effects of anterior load carriage. This gap in the literature is important because many daily (e.g. carrying a laundry basket) and occupational (e.g. courier delivery) activities require loads to be carried in front of the body. Within this context, to further develop the external load-postural stability database we examined the effects of increasing loads carried anteriorly on postural sway and gait parameters in healthy adults. METHODS: Twenty-nine subjects (19 males, 10 females, age = 33.8 ± 12.7 years, height = 1.73 ± 0.07 m, mass = 75.1 ± 13.7 kg) were assessed in four conditions; (1) carrying no load (CON), (2) carrying a load with no added weight (i.e. empty box), (3) carrying a load with 5% body mass, and (4) carrying a load with 10% body mass. Anteroposterior and mediolateral centre of pressure (COP) displacement (cm) and the mean COP velocity (cm·s-1) were used to characterise postural sway. Coefficient of variation of the stride length, stride time and double support time were calculated from 1 min of treadmill walking at a preferred pace for gait assessment. RESULTS: When compared to CON, anteroposterior COP displacement increased with the addition of a 5% (P < 0.001, d = 0.74) and 10% (P < 0.001, d = 1.59) load. The anteroposterior COP displacement also increased from the 5% to the 10% load (P < 0.001, d = 0.75). The addition of the 10% load increased stride time (d = 1.71) and stride length (d = 1.20) variability when compared to CON (P < 0.001). Additionally, stride length variability was significantly greater during 10% compared to 0% (P = 0.004, d = 1.08) and 5% (P = 0.001, d = 1.01) conditions. CONCLUSION: In summary, the increase in postural sway and gait variability with added weight is dependent on the magnitude of the load, where the greater the load, the greater the effect on static and dynamic stability. Changes in the mass-inertia characteristics of the body is one of several mechanisms that have been offered to explain the increased postural sway and gait variability when holding an external load. Given that increased postural sway (Johansson et al. 2017) and gait variability (Verghese et al. 2009) are indicators of increased fall-risk, it can be inferred from the present findings that carrying heavy loads in front of the body increases the likelihood of fall-related incidents.

The paper examines the feasibility of using the H2 rotational Raman spectrum to study the physical structure of the atmospheres of the outer planets. Computations of the strengths of the S(0) and S(1) lines are made for a wide range of physical conditions on the basis of a semi-infinite homogeneous pure H2 atmospheric model. Initial applications of the Raman probe technique to Jupiter and Uranus are reported.

Intensity variation across Uranus disk during limb darkening-brightening cycles observations to test cloud absence theory, predicting limb brightening in methane bands

Reliable data defining the photometric function of the Saturn ring system at visual (V) wavelengths are interpreted in terms of a simple scattering model. To facilitate the analysis, new photographic photometry of the ring has been carried out utilizing the Lowell observatory plate collection. Homogeneous measurements of the mean surface brightness (rings A and B together), covering almost the complete range in planetocentric solar declination angle, are presented. The ring model adopted is a plane-parallel slab of isotropically scattering particles; the single scattering albedo and the perpendicular optical thickness are both arbitrary. Results indicate that primary scattering is inadequate to describe the photometric properties of the ring; multiple scattering predominates for all angles of tilt with respect to the Sun and Earth.