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A Circularly Polarized Parallel Plate Waveguide Lens-Like Multiple-Beam Linear Array Antenna for Satcom Applications

This work presents a full metal circularly-polarized lens-like antenna for Satcom applications at Ka-band. The antenna is composed of two continuous parallel plate waveguide (PPW) quasi-optical beamformers (QOBF), feeding an array of septum polarizers to generate circular polarization. The QOBFs operate over a wide band and provide a multi-beam coverage over a large field of view in the azimuthal plane, while maintaining a relatively simple mechanical design. The array of septum polarizers is based on a stepped profile to generate circular polarization with a good polarization purity in the uplink of Ka-band (27 - 31 GHz). The antenna is fully realized in aluminium. The antenna system provides 14 beams with alternating right/left handed circular polarization (RHCP/LHCP) with an axial ratio (AR) below 3 Db over an angular range of ±19° in the uplink of Ka-Band. The maximum gain in the azimuthal plane at 30 GHz is about 21 dB over the whole angular range, with a scan loss lower than 1.5 dB. The antenna efficiency is better than 78% for all beams in the operative band.

Subcostal versus right lateral ultrasound measurements of inferior vena cava: Measurements obtained from these two views are not equivalent in non-ICU patients.

The objective of this study is to assess concordance between the subcostal and right lateral view for ultrasonographic inferior vena cava measurements including the end-inspiratory diameter, end-expiratory diameter and respiratory variation represented by the caval index in spontaneously breathing healthy adults. We recruited a convenience sample of 33 healthy adults. A phased array ultrasound probe was used to obtain inferior vena cava measurements from a subcostal view in the sagittal plane and from a right lateral view in the coronal plane with B-mode ultrasound. End-inspiratory diameter, end-expiratory diameter and caval index were obtained for each view. A two-tailed t-test was performed to compare the caval indices obtained by the two views. Bland-Altman analysis was used to obtain the limits of agreement for the inferior vena cava diameter and caval index across the two views. Subcostal and right lateral caval indices across all participants were significantly different according to a paired t-test (p < 0.0001). The Bland-Altman analysis showed wide limits of agreement in end-inspiratory diameter (-0.97 and 0.50 cm) and in end-expiratory diameter (-0.94 and 0.90 cm). The right lateral view underestimated the inferior vena cava caval index relative to the subcostal view. The subcostal and right lateral views are not equivalent in obtaining inferior vena cava measurements in spontaneously breathing healthy adults. Current cut-off values for measurement-based applications of inferior vena cava ultrasound, including fluid responsiveness using caval indices, may not be accurate when values are obtained from the right lateral view in the coronal plane of the inferior vena cava in patients.

Advantages of multiple field of view spectrometer

Increasing range of applications of spectral detection has brought more attention to spectrometers. Some of the existing spectrometers are no longer relevant to the demands of the application. High spectral resolution, wide spectral dynamic range, and high compactness are the main features of current spectrometers. We present a multiple field of view spectrometer (MFOVS) concept in the context of a planar diffraction grating spectrometer. By setting multiple field of view (FOV) in the sagittal plane of the spectrometer, spectra from different FOV can be acquired simultaneously by one spectrometer. An area imaging sensor was chosen as the detector to cover the spectrum from all FOVs. A cylindrical lens was placed in front of the detector to control the width of the spectrum in the sagittal direction. In the simulation models, we superimposed the spectra from different FOV to form a spectrum covering a larger area of the detector, or separated the spectra from different FOV spatially so that the spectra from each FOV can be acquired independently. The two design goals mean that the spectrometer was expected to be more sensitive to weak signals or to replace multiple spectrometers with one spectrometer. Experimental prototypes based on practical applications were also presented. The results indicated that MFOVS have the advantages of having a wider spectral dynamic range or simultaneous acquisition of multiple spectral information, depending on the application requirement and design objective.

EFFICACY OF HEMIARTHROPLASTY FOR HUMERAL FOUR-PART FRACTURES IN ELDERLY

Background: There are four anatomic parts of the proximal humerus namely, head, greater tuberosity, lesser tuberosity, and surgical neck. 140 ͦ is the approx angle that is formed by the neck-shaft of the humeral. With prevalence rate of 5-6% among the elderly its incidence increase with the advancement in the age. There are various factors affecting this advancement of the elderly patients towards the proximal humerus including increasing age, osteoporosis, age, sex and other similar factors.&#x0D; Aim: To study the efficacy of Hemiarthroplasty for Humeral Four-part Fractures in Elderly Patients&#x0D; Methods: It was an observational study. 30 patients were taken up for the study, who were diagnosed with humeral fracture. All the patients were included in the study after getting written consent from them. Radiography was done for all the patients from an AP view, a lateral shoulder view in the scapular plane, and of the axilla according to the Neer’s classification.&#x0D; Results: The above table shows that the number of patients was 10 and that of the female patients was 20. The mean age for the patients was 75.45±10.69 years. The VAS score before treatment was found to be ranged from 50-90 and the VAS score after treatment was found to be ranged from 75-95. The above table shows that the VAS pain was 20 in 3 months follow up time that increased to 25 in 1 year follow up time. The VAS disability score within 3 months follow up was 53 that reduced to 47 in 1 year follow-up period. The CMS activity score was in 3 months follow-up was 10.5 and that in 1 year follow up was 15. The CMS mobility after 3 months follow-up was 13 that increased to 22 in 1 year follow-up period.&#x0D; Conclusion: In the light of above results and discussion it is evident that the Hemiarthroplasty is a more viable option for reducing pain and increasing mobility in elderly patients suffering from four-part humeral fracture as compared to any other operative technique.

Validity of a one-item drawing-based instrument to assess trunk deformity perception in kyphotic deformities.

Body image and trunk appearance perception are two crucial attributes in determiningthequality of lifeofindividuals with spinal deformities.The Trunk Appearance Perception Scale (TAPS) is a drawing-based instrument used to evaluate this feature. TheTAPS does not include a sagittal view of the trunkso it is neverbeenusedto assess trunk deformity perception inhyperkyphoticpatients.Thisstudyaimsto analyze theeffect of introducing a newdrawing on the TAPS scalerepresentingthe trunk view in the sagittal plane. 170 non-surgical patients were included (mean age 16.9years and 77.4% women) distributed in three groups. CONTROL group (no deformity): 22 cases;KYPHOSIS group (sagittal deformity): 49 cases and SCOLIOSIS group (coronal deformity): 99 cases (mean Cobb 42.4º). Cross-sectional study.A new drawing (TAPS4) was designed to represent the deformity in the sagittal plane with five response options. Clinical (SRS-22 and TAPS 4-items) and radiological (kyphosis T4-T12) data were collected in all patients. The statistical analysis consisted in determining for each group theinternal consistencyof the 3-items TAPS vs 4-items TAPS, as well as the discriminant validity (correlation with kyphosis magnitude) and convergent validity (correlation with the SRS-22 image subscale).In addition, test-retest reliability of new item 4 was determined in a subgroup of 30 kyphotic patients.During control visit,thepatients received a complete physical examinationanda full-spine AP and lateralX-ray in standing position using a low-radiation technique and fulfilledinstruments TAPS 4 items and SRS-22r. The three groups were found to have statistically significant differencesinthe magnitude ofkyphosis, quality of life, body image perception,the 3-items TAPS,4-itemsTAPS and new item 4score. The addition of the item 4 to TAPS 3 itemsdid not cause a significant change in the internal consistency of the scales (Cronbach's alpha) (TAPS 3-items 0.8 vs. TAPS 4-items 0.8).Kyphosismagnitudewas not correlated with the 3-items TAPS and 4-items TAPSscores; however, in the KYPHOSIS group, a significant negative correlation was observed between kyphosis anditem 4(Rho = -0.4, p = 0.0001).A significant correlation was found in all groups between TAPS 3-items and TAPS 4-items and SRS-22 imagedomain; the correlation betweenitem4 and SRS-22bodyimagedomainwas 0.3 in the Scoliosis group and 0.7 in the Kyphosisgroup. The 4-items TAPS scale does not provide advantages in the assessment of trunk deformity over the 3-items scale. However, in patients with kyphosis, theitem 4 (Kypho-TAPS) alone isavalidand reliableinstrument to monitor the perception of thetrunkdeformity.

Faceted Fresnel DOEs creating the perception of a floating 3D virtual object under divergent illumination

An approach for the optimization and fabrication of a phase-only faceted Fresnel type diffractive optical element (FDOE) creating 3D virtual object is proposed. The FDOE is a transmissive Fresnel type DOE array, which produces the perception of a customized floating 3D virtual object behind the FDOE when illuminated with a divergent monochromatic Light Emitter Diode (LED) source. Each DOE unit of the FDOE is optimized by a modified iterative Fourier transform algorithm (M-IFTA). Every unit of the FDOE locally deflects the incident light to the same position to form a designated view in the target plane. The FDOE is fabricated using our home-built parallel writing photo-lithography machine. Numerical simulations and optical experiments are performed to verify the proposed design method. This work may find important applications in the advanced design of optical security hologram and anti-counterfeiting component.

Facet joint degeneration adversely affects ultrasound imaging of the lumbar spine.

Ultrasound of neuraxis can be used to identify the best possible inter-spinous space to perform neuraxial block.The aim of this study was to assess the anatomical correlation between neuraxial ultrasound and magnetic resonance imaging(MRI). Twenty-one patients who underwent MRI of the lumbar spine had ultrasound of lumbarneuraxis performed by an experienced operator. Each lumbar interspinous space was graded on ultrasound as good [posteriorcomplex (ligamentum flavum and duramater) and anterior complex (posterior longitudinal ligament) visible], intermediate (eitheranterior complex or posterior complex visible) or poor (both anterior complex and posterior complex not visible) in boththe transverse median (TM) and paramedian sagittal oblique (PSO) plane. Pre-determined MRI parameters were measuredby a radiologist blinded to sonographic findings at each inter-spinal level. Seventy-eight lumbar interspinous spaceswere evaluated. There was a significant association (p<0.004) between the facet joint degeneration on MRI and the poor ultrasoundview in the transverse median (TM) group. The odds of obtaining a poor view in TM plane was 7 times higher (95% CI1.7-28.9, p=0.007) in the presence of facet joint degeneration. None of the other variables had a significant association with a poor neuraxial view in the TM plane. Poor views in the parasagittal oblique (PSO) plane did not correlate with any of thevariables measured on MRI. Facet joint degeneration is a major contributing factor to poor neuraxial ultrasoundviews in the TM plane.

The Virtue of Mercy According to Maimonides: Ethics, Law, and Theology

AbstractThis article explores Maimonides’s position with regard to mercy in various aspects—ethics, law, and theology—and examines its unity. The first section discusses Maimonides’s view on the question of mercy in the moral plane: is mercy a virtue? It begins with a short discussion of the Aristotelian stance and then analyzes Maimonides’s view. It shows that Maimonides rejected the philosophical critique of mercy and deemed it a virtue. The second section discusses Maimonides’s view in the judicial plane: may a judge show mercy in judgment and be lenient when ruling? It also explores how Maimonides justifies the negation of mercy in the legal plane in contrast with his view of mercy as a virtue. The third section explores Maimonides’s view of mercy in the theological context. In his discussion of the divine attributes Maimonides interprets the attributes of “merciful and gracious,” and offered a metaphorical interpretation. Since humans are mandated to imitate God, this interpretation has consequences in the normative sphere. The theological discussion therefore raises the question of the moral and legal standing of mercy from a new perspective. It also raises the question of the relation between Maimonides’s position in theGuide of the Perplexedand that in his halakhic compositions. Are these two apparently different positions compatible?

Stellar imaging coronagraph and exoplanet coronal spectrometer: two additional instruments for exoplanet exploration onboard the WSO-UV 1.7-m orbital telescope

The World Space Observatory for Ultraviolet (WSO-UV) is an orbital optical telescope with a 1.7-m diameter primary mirror currently under development. The WSO-UV is aimed to operate in the 115- to 310-nm UV spectral range. Its two major science instruments are UV spectrographs and UV imaging field cameras with filter wheels. The WSO-UV project is currently in the implementation phase, with a tentative launch date in 2023. As designed, the telescope field of view in the focal plane is not fully occupied by instruments. Recently, two additional instruments devoted to exoplanets have been proposed for WSO-UV, which are the focus of this paper. UVSPEX, a UV-spectrograph for exoplanets, aims to determine atomic hydrogen and oxygen abundance in the exospheres of terrestrial exoplanets. The spectral range is 115 to 130 nm, which enables simultaneous measurement of hydrogen and oxygen emission intensities during an exoplanet transit. A study of exosphere transit photometric curves can help differentiate among different types of rocky planets. The exospheric temperature of an Earth-like planet is much higher than that of a Venus-like planet because of the low mixing ratio of the dominant coolant (CO2) in the upper atmosphere of the former, which causes a large difference in transit depth at the oxygen emission line. Thus, whether the terrestrial exoplanet is Earth-like, Venus-like, or other can be determined. A Stellar Coronagraph for Exoplanet Direct Imaging (SCEDI) is aimed to directly detect the starlight reflected from exoplanets orbiting their parent stars or from the stellar vicinity including circumstellar disks, dust, and clumps. SCEDI will create an achromatic (optimized to 420- to 700-nm wavelength range), high-contrast stellocentric coronagraphic image of a circumstellar vicinity. The two instruments, such as UVSPEX and SCEDI, share common power and control modules. The present communication outlines the science goals of both proposed instruments and explains some of their engineering features.

Reciprocal space mapping and strain scanning using X-ray diffraction microscopy

Dark-field X-ray microscopy is a new full-field imaging technique for nondestructively mapping the structure of deeply embedded crystalline elements in three dimensions. Placing an objective in the diffracted beam generates a magnified projection image of a local volume. By placing a detector in the back focal plane, high-resolution reciprocal space maps are generated for the local volume. Geometrical optics is used to provide analytical expressions for the resolution and range of the reciprocal space maps and the associated field of view in the sample plane. To understand the effects of coherence a comparison is made with wavefront simulations using the fractional Fourier transform. Reciprocal space mapping is demonstrated experimentally at an X-ray energy of 15.6 keV. The resolution function exhibits suppressed streaks and an FWHM resolution in all directions of ΔQ/Q = 4 × 10−5 or better. It is demonstrated by simulations that scanning a square aperture in the back focal plane enables strain mapping with no loss in resolution to be combined with a spatial resolution of 100 nm.

Axial plane dissimilarities of two identical Lenke-type 6C scoliosis cases visualized and analyzed by vertebral vectors

The global appearance of scoliosis in the horizontal plane is not really known. Therefore, the aims of this study were to analyze scoliosis in the horizontal plane using vertebral vectors in two patients classified with the same Lenke group, and to highlight the importance of the information obtained from these vertebral vector-based top-view images in clinical practice. Two identical cases of scoliosis were selected, based on preoperative full-body standing anteroposterior and lateral radiographs obtained by the EOS™ 2D/3D system. Three-dimensional (3D) surface reconstructions of the spinal curves were performed by using sterEOS™ 3D software before and after surgery. In both patients, we also determined the vertebral vectors and horizontal plane coordinates for analyzing the curves mathematically before and after surgery. Despite the identical appearance of spinal curves in the frontal and sagittal planes, the horizontal views seemed to be significantly different. The vertebral vectors in the horizontal plane provided different types of parameters regarding scoliosis and the impact of surgical treatment: reducing lateral deviations, achieving harmony of the curves in the sagittal plane, and reducing rotations in the horizontal plane. Vertebral vectors allow the evolution of scoliosis curve projections in the horizontal plane before and after surgical treatment, along with representation of the entire spine. The top view in the horizontal plane is essential to completely evaluate the scoliosis curves, because, despite the similar representations in the frontal and sagittal planes, the occurrence of scoliosis in the horizontal plane can be completely different. These slides can be retrieved under Electronic Supplementary Material.

Inclination of standing posture due to the presentation of tilted view through an immersive head-mounted display

[Purpose] The purpose of the present study is to clarify whether tilted scenery presented through an immersive head-mounted display (HMD) causes the inclination of standing posture. [Subjects and Methods] Eleven healthy young adult males who provided informed consent participated in the experiment. An immersive HMD and a stereo camera were employed to develop a visual inclination system. The subjects maintained a standing posture twice for 5s each while wearing the visual inclination system. They performed this task under two conditions: normal view and 20° leftward tilted view. A three-dimensional motion analysis system was used to measure the subjects’ postures, and two force plates were used to measure the vertical component of the floor reaction force of each leg. [Results] In the 20° leftward tilted view, the head and trunk angles in the frontal plane were similarly inclined toward the left, and the vertical component of the floor reaction force increased in the left leg, whereas it decreased in the right leg. [Conclusion] When the view in the immersive HMD was tilted, the participants’ trunk side bent toward the same side as that of the view. This visual inclination system seems to be a simple intervention for changing standing posture.

Microcomputed tomography-based assessment of retrieved dental implants.

The aim of this study was to demonstrate the potential of microcomputed tomography (micro-CT) technology in the assessment of retrieved dental implants. Cases are presented to illustrate the value of micro-CT imaging techniques in determining possible mechanical causes for dental implant failures. Eight retrieved dental implants were randomly selected from a pool and imaged using a micro-CT device. Source voltages (80 to 100 kV) and source-to-detector distances (65 to 70 mm) were based on signal quality requirements with an additional criterion of achieving the highest resolution with the sample entirely in the field of view in the projection plane. One additional sample was chosen for histology and tomographic imaging so that the information contained therein could be compared. The micro-CT images displayed high contrast between the implant, bone, and background, with negligible metal artifacts. The micro-CT technology used in this study delivered excellent images of the retrieved implants. As a result of the quality and resolution (pixel size: 5.52 to 6.15 μm) of the images, surface morphology as well as internal structures of the retrieved implants could be observed in great detail. The majority of the retrieved implants had increased wear, dents, pits, regular shallow scratches, and deep scratches in the implant-to-abutment engagement area. Furthermore, plastic deformations, microcracks, and brittle implant fractures were observed in two implants. The mechanical competence of dental implant components plays a major role in the success of implant treatment. When failures do occur, a nondestructive three-dimensional assessment of such failed implants and their components is helpful in understanding the underlying factors. Micro-CT was found to be a useful tool for the morphologic assessment of retrieved dental implants.

Line-imaging optical recording velocity interferometer at Shenguang-II laser facility and its applications

A line-imaging optical recording velocity interferometer (VISAR) is implemented at the Shenguang II laser facility. The spatial resolution is ～ 7 m, the effective field of view in the target plane is ～ 1 mm. We propose a new illumination method with increasing three times the luminosity of such a diagnostic. The VISAR is applied to experiments of laser-driven equation of state shockless compression, and shocktiming.

Investigation of portable in situ fluorescence optical detection for microfluidic 3D cell culture assays

A portable fluorescence optical detection system was developed to demonstrate real-time in situ analysis of cells that are three-dimensionally cultured in an extracellular matrix under microfluidic environment. The system was designed to provide a large field of view in the lateral plane to average out cellular processes in an axial layer and simultaneously diffraction-limited axial resolution. In this proof-of-concept study, the detection system was applied to quantitative analyses of short-term measurements of cell staining and cell cytotoxicity and long-term monitoring of a cell-invasion assay. For assays, colon cancer cells were cultured in a Matrigel or alginate matrix. The measured data were largely consistent with predicted results and revealed quantitatively cell dynamics specific to 3D cell cultures. The detection system has a potential as a single package to investigate 3D cultures in a microfluidic system.

What Are You Looking At?

AbstractThere is a rebirth of interest in anamorphic perspective ‐ that erudite artistic trick that allows one to represent different points of view in a single plane or view. Neil Spiller sees a new future for this arcane spatial practice that enables objects to dissolve their muteness. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Assessment of fetal Sylvian fissure operculization between 22 and 32 weeks: a subjective approach

Sylvian fissure operculization (SFO) is a dynamic process throughout gestation and is a reliable feature of fetal cortex gyration that is amenable to prenatal ultrasound examination. This study aimed to define a subjective and reproducible method for SFO assessment. This was a cross-sectional study of the sonographic anatomy of SFO conducted over a 9-month period in 200 fetuses with normal anatomical ultrasound examination at 22-32 weeks of gestation. We used a standardized view in an axial cerebral plane. SFO was scored according to a pre-defined scoring sheet based on the degree of overriding of the insula by the temporal lobe across gestational age. Because of the nested nature of the dataset, linear mixed effects models were used for concurrent assessment of inter- and intraobserver agreement of this scoring method. Subject-specific variance of the score was derived for each week of gestation from the whole repeated-measures dataset and the 5(th) and 95(th) percentiles of the score (mean score(week) +/- 1.645 SD(subject, week)) were determined. The inter- and intraobserver agreement correlation coefficients were 0.91 (0.89-1.00) and 0.95 (0.93-1.00), respectively, with a standard error of measurement < 1 scoring unit, which corresponds to an accuracy of within 1 week. A reference chart was fitted, showing the increase of the SFO score between 22 and 32 weeks, along with age-specific 5(th) and 95(th) percentiles. A simple scoring evaluation of the SFO is a reliable method for its assessment at between 22 and 32 weeks of gestation.

Quadricuspid aortic valve in a patient with mitral valve prolapse

A 72-year-old man was admitted to Yuksek Ihtisas Hospital, Ankara, Turkey, with dyspnea. His medical history was remarkable only for hypertension. On physical examination, his blood pressure was 120/70 mmHg and his pulse rate was 86 beats/min. Cardiac auscultation revealed a grade 3/6 systolic murmur at the apex, and auscultation of the lungs revealed bilateral rales. A 12-lead electrocardiogram showed a normal sinus rhythm. Transthoracic echocardiography demonstrated anterior mitral valve leaflet prolapse with severe mitral regurgitation and a quadricuspid aortic valve with four equal-sized cusps, causing moderate aortic regurgitation, with an X-shaped commissural aspect in diastole. Transesophageal echocardiography demonstrated a quadricuspid aortic valve (Figures 1A and ​and1B)1B) with central moderate aortic regurgitation and a flail segment on the anterior mitral valve leaflet with severe mitral regurgitation. The patient underwent elective mitral valve replacement. Figure 1) A Transesophageal echocardiographic view in the aortic valve plane in diastole. The aortic valve demonstrated a characteristic X pattern with equal-sized cusps. B Transesophageal echocardiographic view in the aortic valve plane in systole. The aortic ... Mitral valve prolapse is a common valvular abnormality. Although the overall prognosis of patients with mitral valve prolapse is excellent, it may cause serious complications, including infective endocarditis, sudden cardiac death, cerebrovascular ischemic events and severe mitral regurgitation (1). The most important complication of mitral valve prolapse is severe mitral regurgitation, which may result from progressive myxomatous degeneration or chordal rupture (1). A quadricuspid aortic valve is a rare congenital malformation of the aortic valve. The main functional abnormality of a quadricuspid aortic valve is insufficiency (2). The structure of a quadricuspid aortic valve varies according to the dimension of each individual valve cusp: four equal cusps, three equal cusps with one minor cusp, or two large cusps with two small cusps (2). In the present case, we presented this rare condition again.

Improved radiological imaging of acetabular screw socket

The improved radiological representation of the cementless acetabular screw-socket at two levels is of fundamental importance for the postoperative determination of position as well as for the judgement of an aseptic loosening. To improve the radiological representation two special radiographic techniques in the anterior-posterior as well as in the axial view have been examined on a human preparation of pelvis and have been scrutinized on a great number of clinical patients. The a.-p. radiography with twenty degrees cranio-caudal prone view in the sagittal plane and the axial radiography with forty-five degrees caudo-cranial prone view in the coronal plane shows the best and fewest overlayed representation of the screw-socket. The position of inclination and anteversion could have been directly determined out of these two radiographs. Malpositions of the screw-socket, especially with regard to the anteversion are easily identifiable due to the special axial radiographic technique. Overprojection of adjoining bone areas, which were possible should be considered at the judgment of the implant-bone-contact. Radiographic technical and positioning problems were not observed in patients. Out of these examinations the a.-p. radiography with twenty degrees cranio-caudal prone view in the sagittal plane and the axial radiography with forty-five degrees caudo-cranial prone view in the coronal plane could be recommended to the radiological diagnosis after implantations of hip prosthesis.

Visual fields of four batoid fishes: a comparative study

The visual fields of elasmobranch fishes are not well characterized even though this is a fundamental element of the visual system. The batoid fishes (skates, rays) form a monophyletic clade within the subclass Elasmobranchii and exhibit a broad range of morphologies and corresponding ecologies. We hypothesized that their visual field characteristics would reflect their diverse morphology and ecology. This was tested by quantifying the monocular, binocular and cyclopean horizontal and vertical visual fields of four batoid species (Raja eglanteria, Urobatis jamaicensis, Dasyatis sabina and Rhinoptera bonasus) that encompassed a range from a basal skate to a more derived ray. The horizontal and vertical visual fields differed significantly among species; however, all species possessed horizontal anterior and dorsal binocular overlaps. Urobatis jamaicensis, a small reef-associated stingray, demonstrated a 360 degrees panoramic visual field in the horizontal plane, and R. bonasus, a schooling benthopelagic ray, a 360 degrees panoramic view in the vertical plane. Large anterior binocular overlaps were measured in D. sabina (72 degrees ) and R. bonasus (46 degrees ) but came at the expense of large posterior blind areas. The anterior binocular overlaps in R. eglanteria (28 degrees ) and U. jamaicensis (34 degrees ) were smaller but were coupled with large monocular fields that provided expansive peripheral views. The most phylogenetically basal species, the clearnose skate (Raja eglanteria), had the most reduced visual field in contrast to the more derived ray species. To our knowledge, this study represents the first comparative assessment of visual fields in basal vertebrates.