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AIM To investigate whether pattern reversal visual evoked potentials (PRVEPs) could predict future visual acuity in infants with cerebral visual impairment (CVI). METHOD Fifty-five children (27 males, 28 females) with severe CVI seen in the ophthalmology department of a specialist children's hospital were identified retrospectively. Behavioural visual acuity and visual evoked potentials (VEPs) at presentation (time 1, T1) were compared with final visual acuity at late preschool/early school age (time 2, T2). Predictors of visual acuity at T2 were identified using univariate and multivariate logistic and linear regression analysis. RESULTS Median age was 14 months at T1 (range: 6-44mo) and 63 months at T2 (range: 29-150mo). The presence of a PRVEP produced by a check width of 50' (minutes of arc) or smaller (T1) predicted (p=0.05) the presence of measurable preferential looking acuity at T2. The presence of PRVEP to check widths of 25' or smaller (T1) predicted (p=0.02) better preferential looking acuity (logMAR-equivalent) scores at T2. The latter association was independent of presenting acuity at T1. INTERPRETATION The presence of PRVEPs to check widths of 50' and 25' in infancy provided useful information. VEPs in young children with CVI may have prognostic value regarding future acuity.

At a spatial resolution level of 5 by 5 arc minute, we estimate anthropogenic nitrogen (N) loads to freshwater, globally. The global anthropogenic N load to freshwater systems from diffuse and point sources in the period 2002–2010 was 32.6 million tonnes per year. China contributed about 45% to this global anthropogenic N load. The USA was the second largest contributor (7%), followed by Russia (6%) and India (5%). Three quarters of the N loads came from diffuse sources (agriculture), 23% from domestic point sources and 2% from industrial point sources. Among the crops, production of cereals had the largest contribution to the N loads (18%, of which 7% wheat and 6% maize), followed by vegetables (15%) and oil crops (11%). It is estimated that, globally, 18% of the total N input on crop fields in the form of artificial fertilizer and manure leaches to freshwater systems.

NESSI (New Mexico Exoplanet Spectroscopic Survey Instrument) was originally conceived, designed and built under a NASA NM-EPSCoR funded effort as a near-infrared multi-object spectrograph for characterizing exoplanet transits at the Magdalena Ridge Observatory. With the help of funding from JPL, we are moving NESSI to its new home on the Hale telescope in early 2018. Salient features of the New NESSI include a 6.5 arc minute field-of-view, low (R~250) or moderate (R~1100) spectral resolutions across J, H and/or K bands, the ability to stare at transits with high frame-rates, and finally a suite of on-board filters for imaging applications. We present the new design of NESSI, lessons learned in the refurbishment process, as well as an update for next steps in the process.

PURPOSE: To determine the size of a halo in the visual field induced by bright light in healthy eyes of all ages using the Vision Monitor (MonCv3; Metrovision, Pérenchies, France) and to assess the repeatability of the method. METHODS: Measurements were made in the right eyes of 147 healthy subjects (mean age: 48.2 ± 16.2 years) who were classified into six age groups. Using the Vision Monitor, optotypes of low luminance were presented at a distance of 2.5 m. The visual angle subtended by the radius of the halo was calculated in minutes of arc (arc min). The repeatability of the method was determined in a subset of 37 subjects older than 50 years by calculating the Bland–Altman coefficient of repeatability. RESULTS: The mean radius of the halo was 111.6 ± 39.8 arc min. Halo radius started to increase significantly from the age of 50 to 59 years. The relationship between halo radius and age (r = 0.65; P < .0001) was described by fitting a power function to the data. Halo size was independent of gender. The coefficient of repeatability of the method was ±44 arc min. CONCLUSIONS: Halo size increases with age following a power model. The normal halo size values provided could help clinicians distinguish between normal or abnormal glare problems. The intersession repeatability observed for halo size measurement indicates this method could be useful for assessing visual impairment caused by glare. [ J Refract Surg. 2013;29(9):618–622.]

The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High Energy Astrophysics (Athena), will provide high spectral resolution (2.5 eV up to 7 keV) over a 5 arc minute (equivalent diameter) field of view. The X-IFU is currently in the middle of its Phase A study phase. In this paper, we review the technical challenges (system level issues, TES array, readout, cooling, …) as identified during the first year of the study. This instrument is developed by a large international consortium under a French leadership. The Netherlands and Italy, as Co-PIs, with ESA member state from Belgium, Finland, Germany, Poland, Spain, Switzerland, are the European contributors, with additional contributions from the United States and Japan.

Galactic cirrus emission at far-infrared wavelengths affects many extragalactic observations. Separating this emission from that associated with extragalactic objects is both important and difficult. In this paper we discuss a particular case, the M81 group, and the identification of diffuse structures prominent in the infrared, but also detected at optical wavelengths. The origin of these structures has previously been controversial, ranging from them being the result of a past interaction between M81 and M82 or due to more local Galactic emission. We show that over of order a few arcminute scales the far-infrared (Herschel 250 &\mu&m) emission correlates spatially very well with a particular narrow velocity (2-3 km/s) component of the Galactic HI. We find no evidence that any of the far-infrared emission associated with these features actually originates in the M81 group. Thus we infer that the associated diffuse optical emission must be due to galactic light back scattered off dust in our galaxy. Ultra-violet observations pick out young stellar associations around M81, but no detectable far-infrared emission. We consider in detail one of the Galactic cirrus features, finding that the far-infrared HI relation breaks down below arc minute scales and that at smaller scales there can be quite large dust temperature variations.

We compared the pattern reversal visual evoked response (PVER) amplitude-check size functions from 25 eyes (25 normal subjects; visual acuities > or = 20/20) with those from 32 eyes (22 patients; visual acuities 20/15 to 20/50; mean, 20/25.5) with mild optic nerve disease to determine if spatial tuning loss of the PVER occurs in the presence of optic nerve dysfunction. The steady-state PVER was recorded with five check sizes (range, 160 to 10 minutes of arc). To analyze the PVER amplitude-check size function, we calculated the difference between the maximum and minimum PVER amplitudes and then calculated the area of spatial tuning (the area under the function). Values were significantly smaller in patients than in normal subjects (1.81 +/- 1.27 microV versus 5.73 +/- 3.27 microV; F = 41.24, p = 0.0001; 3.87 +/- 2.70 area units versus 12.57 +/- 7.60 area units; F = 38.62, p = 0.0001). There was no shift in the distribution of peak check sizes. Results suggest that a spatial tuning loss occurs in optic nerve disease. The shape of the function, including the area of spatial tuning, appears to be a sensitive indicator of early or mild optic nerve dysfunction.

International audience; During fixation, the eyes are not still but often exhibit microsaccadic movements. The function of microsaccades is controversial, largely because the neural mechanisms responsible for their generation are unknown. Here, we show that the superior colliculus (SC), a retinotopically organized structure involved in voluntary-saccade target selection, plays a causal role in microsaccade generation. Neurons in the foveal portion of the SC increase their activity before and during microsaccades with sizes of only a few minutes of arc and exhibit selectivity for the direction and amplitude of these movements. Reversible inactivation of these neurons significantly reduces microsaccade rate without otherwise compromising fixation. These results, coupled with computational modeling of SC activity, demonstrate that microsaccades are controlled by the SC and explain the link between microsaccades and visual attention.

I have examined over 1500 historical tsunami travel-time records for 127 tsunamigenic earthquakes that occurred in the Pacific and Indian Oceans. After subjecting the observations to simple tests to rule out gross errors I compare the remaining reports to simple travel-time predictions using Huygens method and the long-wave approximation, thus simulating the calculations that typically take place in a tsunami warning situation. In general, I find a high correspondence between predicted and reported travel times however, significant departures exist. Some outliers imply significantly slower propagation speeds than predicted; many of these are clearly the consequences of observers not being able to detect the (possibly weak?) first arrivals. Other outliers imply excessively long predicted travel times. These outliers reflect peculiar geometric and bathymetric conditions that are poorly represented in global bathymetric grids, leading to longer propagation paths and consequently increased travel times. Analysis of Δt, the difference between observed and predicted travel time, yields a mean Δt of 19 minutes with a standard deviation of 131 minutes. Robust statistics, being less sensitive to outliers, yield a median Δt of just 18 seconds and a median absolute deviation of 33 minutes. Care is needed to process bathymetry to avoid excessive travel-time delays in shallow areas. I also show that a 2×2 arc minute grid yields better results that a 5×5 arc minute grid; the latter in general yielding slightly slower propagation predictions. The largest remaining source of error appears to be the inadequacy of the point-source approximation to the finite tsunami-generating area.

Methods for accelerometer unit calibration are usually based on sufficiently strict requirements on the knowledge of the gravity orientation with respect to the unit (of the order of fractions of an arc minute). But it is not always possible to know the orientation with such high accuracy. In the present paper, we consider an approach to accelerometer unit calibration for whose implementation it suffices to have rough angular information (of the order of tens of arc minutes). We use a guaranteeing approach to calculate optimal schemes calibration experiments and propose an iterative scheme of calibration.

PURPOSE: To compare disk halo size in response to a glare source in eyes with an aspheric apodized diffractive multifocal intraocular lens (IOL) or aspheric monofocal IOL. SETTING: Rementeria Ophthalmological Clinic, Madrid, Spain. DESIGN: Prospective randomized masked study. METHOD: Halo radius was measured using a vision monitor (MonCv3) with low-luminance optotypes in eyes that had cataract surgery and bilateral implantion of an Acrysof Restor SN6AD1 multifocal IOL or Acrysof IQ monofocal IOL 6 to 9 months previously. The visual angle subtended by the disk halo radius was calculated in minutes of arc (arcmin). Patient complaints of halo disturbances were recorded. Monocular uncorrected distance visual acutity (UDVA) and corrected distance visual acuity (CDVA) were measured using high-contrast (96%) and low-contrast (10%) logMAR letter charts. RESULTS: The study comprised 39 eyes of 39 subjects (aged 70 to 80 years); 21 eyes had a multifocal IOL and 18 eyes a monofocal IOL. The mean halo radius was 35 arcmin larger in the multifocal IOL group than the monofocal group (P

Working with computer usually required prolonged static sitting. Both static work and awkward posture are well known as the two major ergonomie risk factors in such activity. Workstation arrangement guidelines are usually suggested based on good working posture. In this study, rather than investigating on the physical dimensions of the workstation (i.e., table and chair) like others, we look into the font size factor instead. Our research is separated into two phases. The first phase is to study the effect of font size (8 moa, 12 moa, 16 moa, and 24 moa) and viewing distance on working performance as measured by text-entering speed. Our results show that both factors are not significant (p-value = 0.464 and 0.913 respectively). Then, in the second phase, we look at whether there are tendency of sitting posture change due to the different font size. Our findings show significant difference on neck angle (p-value = 0.007) but not back angle (p-value = 0.314). Our finding suggests that there are more posture deviations under smaller font size conditions.

Vision provided the obvious source of determining the dimensions of nerve fibers when suitable achromatic microscopes were directed at neural tissue in the 1830s. The earlier microscopes of Hooke and Leeuwenhoek were unable to resolve such small structures adequately. However, it was not Hooke's microscope that led to an estimate of the dimensions of nerve fibers, but his experiments on the limits of visual resolution; he determined that a separation of one minute of arc was the minimum that could normally be seen. Descartes had earlier speculated that the retina consisted of the ends of fibers of the optic nerve, and that their size defined the limits of what could be seen. Estimates of the diameters of nerve fibers were made on the basis of human visual acuity by Porterfield in 1738; he calculated the diameters of nerve fibers in the retina as one 7,200th part of an inch (0.0035 mm), based on the resolution of one minute as the minimum visible. In the same year, Jurin questioned the reliability of such estimates because of variations in visual resolution with different stimuli.

H.E.S.S. is an experiment for ground based GeV/TeV gamma ray astronomy of the new generation. It consists of four large Cherenkov telescopes operating in stereoscopic observation mode. Its construction in Namibia was completed at the end of 2003. Already during the installation phase, exciting results have been achieved, and after completion several discoveries have been made. Some of the results and discoveries are reported, such as the first image of a shell-type supernova remnant resolved at arc minute scale (RXJ 1713 – 3946), the discovery of the unique binary pulsar system PSR B1259 – 63 and of a yet-unidentified source in the same field of view (HESS J1303 – 631), and the observation of the galactic centre region. Amongst the extragalactic sources, the blazers Mkn 421 and PKS 2155 – 304 have also been detected.

This paper presents formulas for the calculation of the refraction anomalies caused by the inclination of atmospheric boundary layers. Anomalies were calculated for a few zenith distances for several different atmospheric models. It was established, that near Earth the atmospheric boundary layers have the global inclination in meridian plane near one minute of arc from North to South. They are calculated with standard deviation ±0.2′–±0.35′. The tilts are decreased gradually with the altitude and equal nearly 0 on the heights 8–10 km. Then direction of inclination is changed on opposite (from South to North) and maximum 1′ reaches on the heights 15–18 km. Next inclinations slowly decrease and equal 0 on the heights 28–30 km. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Background: New computer-controlled psychophysical procedures allow one to measure some temporal aspects of binocular coordination. The present study investigates whether these procedures can be operated by children and whether the tests are useful to detect previously reported impairments in dynamics and stability of vergence in children with disability in reading and writing. Methods: To assess the variability in vergence accuracy (fixation disparity), a stationary fusion stimulus appeared on a computer monitor superimposed by short-term presentations of two dichoptic vertical nonius lines with varying horizontal offset. From the variability of the responses, a measure of vergence variability was deduced. Vergence velocity was estimated with nonius lines that appeared at a fixed delay of 400 ms after a sudden change in disparity of 30 minutes of arc. The full sample comprised 66 children, aged 7-16 years. 16 of these were not able to localize the nonius lines accurately in a control condition; therefore, these children were excluded from the following analysis. Results: In the remaining 50 children, a group of 30 pupils with different aspects of disability in reading and writing had a nearly significant worse vergence performance both with respect to convergence velocity and to variability of fixation disparity (as compared to a control group of n=20). These two findings corresponded to each other since convergence velocity and variability of fixation disparity were correlated. Conclusions: The results confirm previous reports and suggest further research on temporal aspects of vergence with respect to dyslexia. The computer-controlled test procedures are applicable in children of about 10 years or older.

In re-ionized models, the measurement of polarization of CMBR can be a good criterion to narrow down the parameter space for cosmological models. A Vishniac-type effect in second order polarization over arc minute scales has been calculated. It has been shown that while the effect is very small (∼10−2 µK) for CDM models, it can be significant (∼0.3µK) for some isocurvature models.

In this paper we demonstrate a new alignment device in which we use the five parallel laser beams each set to rapidly and accurately align their corresponding optical axis of porro prism binocular (PPB). At all interpupillary distances (IPD), this technique assures parallelized right and left optics axis of PPB. In this method the left and right optical axis of a PPB are made parallel to each central beam of two “five parallel laser beams alignment devices” in the plane of incidence. And above process is assured by examining the direction of these five transmitted laser beams that transmitted through PPB in the way that the height and orientation of the PPB are fine tuned. The parallelism of the left and right optical axis of the PPB was measured by laser rangefinder. This novel method is used to obtain the parallelism of left and right optical axis of PPB in a maximum tolerance of three arc minute.

et al., [Purpose]: The purpose of this study was to assess the orientation of the anterior and posterior corneal surfaces with respect to the keratometric axis in the three-dimensional space. [Methods]: A group of 407 normal corneas of 211 subjects with ages ranging from 4 to 79 years was analyzed by fitting their elevation topographies to a general three-axes ellipsoid model. [Results]: The resulting average tilt (-1.20 degrees) and tip (1.83 degrees) of the anterior surface are consistent with previous findings. In addition, we found that the posterior surface is also misaligned with the anterior by a similar amount. The cornea seems to rotate as a solid body by 2 minutes of arc per year. [Conclusions]: The misalignment between the cornea and the keratometric axis increases as a function of age. This tiny, but significant (p < 0.005), rotation may have an important impact on optical quality because it could cause an important increase of the higher order aberrations of the cornea with age.Copyright © 2013 American Academy of Optometry.

An experiment was conducted to investigate the main and interaction effects of screen distances (600 mm and 900 mm), screen letter heights (for visual angles of 16, 20, and 30 minutes of arc), and source document distances (same as the screen distance and closer than the screen distance) on visual performance and subjective preference in text proofreading tasks. Thirty subjects in different age groups participated in the experiment. The experimental results revealed that the subjects' performance improved from the letter height of 16 minutes of arc to the letter height of 20 minutes of arc for the 600 mm screen distance, but from 20 minutes of arc to 16 minutes of arc for the 900 mm screen distance. The subjects generally preferred a screen distance slightly higher than 600 mm, a letter height at the 22 minutes of arc, and a small difference between the visual angle of screen letters and the visual angle of source letters.

Several computerized procedures for determination of the axis-angle pair characterizing grain misorientation in bicrystals using Laue patterns are described. The procedures are based on the linear least squares fit method; they are rapid and easy to use. One of the procedures can be used for determination of single-crystal orientation. It is necessary to measure the coordinates of spots and the origin in the reference system of the Laue pattern and find the indices hkl of at least two spots. Attention is paid to accuracy of determination of the rotation axis and rotation angle. In favourable cases of orientation, they are determined with a precision of several minutes of arc.

Aggregate measures that capture multiple aspects of socio-ecological vulnerability in a single or small number of vulnerability indices can produce vulnerability maps that act as powerful visual tools to identify those areas most susceptible to future environmental changes. Such indices are easily communicable and offer valuable guidance to policymakers and investors, providing insights as to where more targeted research or policy interventions can address current challenges and reduce future risks. However, such aggregation inevitably reduces the richness of information provided by the suites of individual vulnerability indicators on which the maps are based. This trade-off between information richness and information communicability is a challenge in the quantification and communication of complex phenomena such as socio-ecological vulnerability. This paper investigates the use of Principal Component Analysis (PCA) techniques as a means of creating information-rich spatially-explicit aggregate indices of socio-ecological vulnerability. We present a ‘proof of concept’ analysis of socio-ecological vulnerability for the Southern Africa Development Community (SADC) region using both PCA and traditional normalization based techniques for generating spatially explicit, aggregated socio-ecological vulnerability indices. The vulnerability indices are based on published biophysical and socio-economic data and mapped at a 10 arc minute resolution. The resulting PCA based vulnerability maps indicate the regional spatial variability of four statistically independent, unique components of socio-ecological vulnerability, providing more information than the single index produced using a normalization/summation approach. Such uncorrelated, information-rich vulnerability indices represent a potentially useful policy tool for identifying areas of greatest concern in terms of both the relative level, and the underlying causes and impacts of, socioecological vulnerability to environmental changes across broad spatial scales. Aggregate measures that capture multiple aspects of socio-ecological vulnerability in a single or small number of vulnerability indices can produce vulnerability maps that act as powerful visual tools to identify those areas most susceptible to future environmental changes. Such indices are easily communicable and offer valuable guidance to policymakers and investors, providing insights as to where more targeted research or policy interventions can address current challenges and reduce future risks. However, such aggregation inevitably reduces the richness of information provided by the suites of individual vulnerability indicators on which the maps are based. This trade-off between information richness and information communicability is a challenge in the quantification and communication of complex phenomena such as socio-ecological vulnerability. This paper investigates the use of PrincipalComponent Analysis (PCA) techniques as a means of creating information-rich spatially-explicit aggregate indices of socio-ecological vulnerability.We present a ‘proof of concept’ analysis of socio-ecological vulnerability for the Southern Africa Development Community (SADC) region using both PCA and traditional normalization based techniques for generating spatially explicit, aggregated socio-ecological vulnerability indices. The vulnerability indices are based on published biophysical and socio-economic data and mapped at a 10 arc minute resolution. The resulting PCA based vulnerability maps indicate the regional spatial variability of four statistically independent, unique components of socio-ecological vulnerability, providing more information than the single index produced using a normalization/summation approach. Such uncorrelated, information-rich vulnerability indices represent a potentially useful policy tool for identifying areas of greatest concern in terms of both the relative level, and the underlying causes and impacts of, socioecological vulnerability to environmental changes across broad spatial scales.

PURPOSE: To investigate the effect of intraocular straylight (IOS) induced by white opacity filters (WOF) on threshold measurements for stimuli employed in three perimeters: standard automated perimetry (SAP), pulsar perimetry (PP) and the Moorfields motion displacement test (MDT).¦METHODS: Four healthy young (24-28 years old) observers were tested six times with each perimeter, each time with one of five different WOFs and once without, inducing various levels of IOS (from 10% to 200%). An increase in IOS was measured with a straylight meter. The change in sensitivity from baseline was normalized, allowing comparison of standardized (z) scores (change divided by the SD of normative values) for each instrument.¦RESULTS: SAP and PP thresholds were significantly affected (P < 0.001) by moderate to large increases in IOS (50%-200%). The drop in motion displacement (MD) from baseline with WOF 5, was approximately 5 dB, in both SAP and PP which represents a clinically significant loss; in contrast the change in MD with MDT was on average 1 minute of arc, which is not likely to indicate a clinically significant loss.¦CONCLUSIONS: The Moorfields MDT is more robust to the effects of additional straylight in comparison with SAP or PP.

Summary Two sextants constructed for Tycho Brahe are preserved in the National Technical Museum in Prague. One was constructed by Erasmus Habermel, the other by Jost Burgi. Both were made in the year 1600. To overcome the observational errors, several improvements were made in the construction of these instruments, especially in the case of Burgi's sextant. It would appear both from these instruments and from his tables of sines that Tycho wanted to reduce the errors to one minute of arc. A replica of Burgi's sextant, which is currently under construction, will allow the accuracy of the instrument to be tested.

The participation in BRITE Consortium gives Poland the possibility to launch into space the first Polish scientific satellite. This paper presents the Polish technical contribution to the BRITE Program to be realized in two institutes of the Polish Academy of Sciences: Nicolaus Copernicus Astronomical Center and Space Research Center.. BRITE Constellation, short for "BRIght Target Explorer Constellation," is a group of up to six nano-satellites whose purpose is to photometrically measure low-level oscillations and temperature variations in the sky's 286 stars brighter than visual magnitude 3.5, with unprecedented precision and time sampling not achievable through terrestrial-based methods. The three-axis pointing performance (1 arc minute rms stability) of each BRITE satellite is a significant advancement over anything that has ever flown before on a nano-satellite and is an important factor that enables the high precision photometry mission. The paper summarizes the technical details of the BRITE satellite based on Generic Nanosatellite Bus from SFL/UTIAS. The first Polish satellite, BRITE -PL 1, will be a modified version of the original SFL design. The second Polish satellite, BRITE-PL 2, will include the significant changes to be implemented by SRC PAS.

Shortly after opening, the Vancouver mass transit system experienced severe rail and wheel corrugation problems. Poor alignment of wheelsets in trucks, generation of ‘roll-slip’ oscillations between wheel and rail and the development of close conformity between the wheel tread and the rail were judged to be associated with the development of corrugations. Remedies included reducing the tolerance on wheelset misalignment to ±10 minutes of arc, applying a friction modifier to wheels to change the friction characteristic between wheel tread and rail from negative to positive, regauging the track and grinding the rail to different profiles in each of the four equal sections of tangent track. These remedies have virtually eliminated corrugation from the system.

Purely symmetrical vergence stimuli aligned along the midline (cyclopean axis) require only a pure vergence response. Yet, in most responses saccades are observed and these saccades must either produce an error in the desired midline response or correct an error produced by asymmetry in the vergence response. A previous study (Semmlow, et al. 2008) has shown that the first saccade to appear in a response to a pure vergence stimulus usually increased the deviation from the midline, although all subjects (N = 12) had some responses where the initial saccade corrected a vergence induced midline error. This study focuses on those responses where the initial saccade produces an increased midline deviation and the resultant compensation that ultimately brings the eyes to the correct binocular position. This correction is accomplished by a higher level compensatory mechanism that uses offsetting asymmetrical vergence and/or corrective saccades. While responses consist of a mixture of the two compensatory mechanisms, the dominant mechanism is subject-dependent. Since fixation errors are quite small (minutes of arc), some feedback controlled physiological process involving smooth eye movements, and possibly saccades, must move the eyes to reduce binocular error to fixation disparity levels.

The Gemini Multi-Conjugate Adaptive Optics project was launched in April 1999 to become the Gemini South AO facility in Chile. The system includes 5 laser guide stars, 3 natural guide stars and 3 deformable mirrors optically conjugated at 0, 4.5 and 9km to achieve near-uniform atmospheric compensation over a 1 arc minute square field of view. Sub-contracted systems with vendors were started as early as October 2001 and were all delivered by July 2007, but for the 50W laser (due around September 2008). The in-house development began in January 2006, and is expected to be completed by the end of 2008 to continue with integration and testing (I&T) on the telescope. The on-sky commissioning phase is scheduled to start during the first half of 2009. In this general overview, we will first describe the status of each subsystem with their major requirements, risk areas and achieved performance. Next we will present our plan to complete the project by reviewing the remaining steps through I&T and commissioning on the telescope, both during day-time and at night-time. Finally, we will summarize some management activities like schedules, resources and conclude with some lessons learned.

NOAA’s National Geophysical Data Center (NGDC) has extensive holdings of airborne and marine magnetic data. Such data have been collected for more than half a century, providing global coverage of the Earth. Due to the changing main field from the Earth’s core, and due to differences in quality and coverage, combining these data to a consistent global magnetic anomaly grid is challenging. A key ingredient is the long wavelength magnetic field observed by the low-orbiting CHAMP satellite. To produce a homogeneous grid, the marine and aeromagnetic trackline data are first line-leveled and then merged with the existing grids of continental-scale compilations by Least Squares Collocation. In the final processing step the short-to-intermediate wavelengths of the near-surface grid are merged with a CHAMP satellite magnetic anomaly model. In analogy to NGDC’s 2-arcminute resolution ETOPO2 grid, we call our initial 3-arcminute magnetic anomaly grid EMAG3. The grid will be updated regularly. It is available in digital form and as plug-ins for NASA World Wind and Google Earth.

The automatic calibration system for 3-component vector DC magnetometers of Nurmijarvi Geophysical Observatory (Finland) is in operation for more than 10 years. It is based on a three axes reference coil system and Observatory reference magnetometer. It is shown experimentally that the system allows determining of magnetometer transformation factor with an error below 0.02% and angle errors (non-orthogonality of the magnetometer axes and angles between mechanical and magnetic axes) with error below 1 arc minute. During this period the parameters of the system were measured routinely with absolute measure. In the paper the infrastructure of the system is described and also the procedure of its accrediting is proposed

Stereoscopic images while providing enhanced depth and image quality can cause moderate discomfort. In this paper, we present the results of two experiments aimed at investigating one possible source of discomfort: whole-field vertical disparities. In both experiments, we asked viewers to rate their comfort level while viewing a 3D feature film in which the left and right images were vertically misaligned. The feature film was presented on a large theater type screen. In Experiment 1, the vertical offset was changed randomly on a scene-by-scene basis resulting in an average vertical disparity of 31 minutes or arc at the closest viewing distance. The results showed that whole- field vertical disparities produced a marginal increase in discomfort that became only slightly more pronounced with time. In Experiment 2, we alternated periods of low, medium and high levels of whole-field vertical disparity. At the closest distance, the mean vertical disparity was 15, 30, or 62 minutes of arc for the low, medium and high disparity conditions, respectively. In this experiment, discomfort increased with vertical disparity, but again only marginally even after prolonged exposure. We conclude that whole-field vertical disparities cannot be a major contributor to the discomfort experienced by observers when viewing stereoscopic images.

Livestock contributes directly to the livelihoods and food security of almost a billion people and affects the diet and health of many more. With estimated standing populations of 1.43 billion cattle, 1.87 billion sheep and goats, 0.98 billion pigs, and 19.60 billion chickens, reliable and accessible information on the distribution and abundance of livestock is needed for a many reasons. These include analyses of the social and economic aspects of the livestock sector; the environmental impacts of livestock such as the production and management of waste, greenhouse gas emissions and livestock-related land-use change; and large-scale public health and epidemiological investigations. The Gridded Livestock of the World (GLW) database, produced in 2007, provided modelled livestock densities of the world, adjusted to match official (FAOSTAT) national estimates for the reference year 2005, at a spatial resolution of 3 minutes of arc (about 5×5 km at the equator). Recent methodological improvements have significantly enhanced these distributions: more up-to date and detailed sub-national livestock statistics have been collected; a new, higher resolution set of predictor variables is used; and the analytical procedure has been revised and extended to include a more systematic assessment of model accuracy and the representation of uncertainties associated with the predictions. This paper describes the current approach in detail and presents new global distribution maps at 1 km resolution for cattle, pigs and chickens, and a partial distribution map for ducks. These digital layers are made publically available via the Livestock Geo-Wiki (http://www.livestock.geo-wiki.org), as will be the maps of other livestock types as they are produced., SCOPUS: ar.j, info:eu-repo/semantics/published

The FAR.XITE is a proposed balloon payload. After a test flight, our initial goal is to fly 10 nested mirror modules, but then even more modules can be added until the mass limit of the pointing system and balloon gondola are reached. These limits are yet to be determined. In our design, Wolter I mirrors are coated with multilayers that allow FAR.XITE to reach 100 keV with better than 1 arc minute angular resolution. We summarize the science objectives, optical design and specifications that were previously reported, and present our recent results of advances in X-ray mirror and detector.

Publisher Summary This chapter discusses the concept of linear combinations of ordered symmetric observations and its applications to visual acuity. In vision research, the Snellen chart is commonly used to assess visual acuity and is made up of letters of graduated sizes. By combining letter size and chart distance, it is possible to determine the minimum visual angle of retinal resolution. A visual acuity of 20/30 means that at 20 feet the minimum angle of resolution is times the resolution standard (about 5 minutes of arc). The vision of a normal eye is recorded as 20/20 and corresponds to zero in the scale determined by the logarithm of the minimum angle of resolution (Log MAR). Normally, a single measure of visual acuity is made in each eye, say Y 1 , Y 2 , together with one or more covariates X , such as the subject's age, reading performance, physical condition, etc. Because smaller values of Log MAR correspond to better visual acuity, the extremes of visual acuity are defined in terms of the “best” acuity Y (1) = min{ Y 1 , Y 2 } and the “worst” acuity Y (2) = max{ Y 1 , Y 2 }. Ordered acuity measurements are also required to determine the person's total vision impairment.

GPA is an expression that describes how the number of dots/inch and the number of graylevels/dot tradeoff in determining the number of graylevels per area (GPA). The metric is based on the assumption that anything that falls within a visual angle of approximately 3 minutes of arc will be spatially-integrated by the optical blur properties of our eyes.

The observation of an area of 120° × 56° centered on RA=8 h DEC=20° at 408 MHz was the first astronomical use of the MPIfR 100-m telescope (1970) and was designed to compile a complete sky survey using also data from Jodrell Bank and Parkes (Haslam et al., 1982). The observation of the northern sky at 1420 MHz started in 1972 using the Stockert 25-m telescope and was finished in 1976 (Reich and Reich 1986). This survey has been completed to an all sky survey using data from Villa Elisa (Argentina). The two surveys are absolutely calibrated. The angular resolutions are 0.8° and 0.59°, respectively. A number of surveys of the Galactic plane have been made with the 100-m telescope at arc minute angular resolution. Surveys at 2695 MHz (|b| ≤ 5°) (Reich et al. 1990, Furst et al. 1990) and at 1410 MHz (|b| ≤ 4°) (Reich et al. 1990) are public.

Background: Grating acuity measured by Teller cards Is mildly reduced in children with developmental delay. Vernier acuity, the ability to detect offsets, also can be measured, but has not been studied in children with developmental delay. Methods: In a prospective cross-sectional pilot study, 12 nonverbal children with developmental delay established by pediatrie assessment of developmental milestones were tested blnocularly with vernier and Teller cards. Ages ranged from 4 to 24 months. Vernier offsets ranged from 2 to 64 minutes of arc. Results: All children were testable with Teller acuity cards. Binocular grating acuity ranged from 1.7 to 7.4 cpd (median, 1.0 octaves below normal). Binocular vernier acuity ranged from unrecordable to 8 minutes of arc (median, "unrecordable"). Only four of the 12 children demonstrated a measurable vernier acuity. Normal children of this age have a vernier acuity of 2 to 16 minutes of arc measured by this technique. Conclusion: The response to vernier acuity cards appears to be more severely degraded by developmental delay than the response to Teller cards.

Between 1992 October 4 and 1993 August 1, 11 GRBs were concurrently observed by CGRO, Mars Observer (MO), and Ulysses. Unfortunately, for all but one of the events MO was in a low-time-resolution mode. Arrival time analysis was used to compute error boxes whose larger dimensions are typically of the same order as the diameters of the BATSE-only boxes and whose smaller dimensions are in the arc minute range. By and large, our arrival-time results are consistent with the BATSE RMS errors stated in the 3B Catalog. That is, the mean uncertainty in the locations of the stronger BATSE events appears to be about 2 degrees.

The celestial bodies appear to us slightly higher above the horizon than they really are, and this displacement increases the nearer they get to the horizon. This accounts for the flattening of t he sun and the moon on the horizon. At sunset, the lower edge o f the sun’s disk appears, on average, 35 minutes of arc higher than it actually is, but the top edge, which is farther from the horizon, only 29. The flattening amounts, therefore, to 6 minutes of arc, or about 1/5 of the sun’s diameter.

A new system of infrared oculography has been developed which provides binocular recordings and allows simultaneous measurement of horizontal and vertical eye movements. The sensitivity of the system is 1 minute of arc, and it has a horizontal range of +/- 30 degrees and a vertical range of +/- 20 degrees. Using this system for routine clinical evaluations, it was possible to record divergent spontaneous nystagmus and divergent thermally induced nystagmus. Rotatory nystagmus can also be recorded. The binocular infrared oculographic system (BIRO) satisfies nearly all the requirements of an ideal recording system.

A number of meteorological models at the Air Force Global Weather Central (AFGWC) make use of eighth mesh resolution terrain elevation and geography (land/coastline/water) data sets. Unfortunately, the data sets currently in use at AFGWC are of extremely poor quality. Therefore, as part of GL efforts to upgrade the Real-Time Nephanalysis Model, new hemispheric eighth mesh (approximately 25 nautical mile resolution) data sets were developed. The global Navy 10 arc minute terrain elevation and land characteristics data (approximately 10 nautical mile resolution) were used as source data. This report describes the averaging and remapping techniques used in the development of these new accurate hemispheric data sets.

It is shown that the Slingram-type TEM systems that have been successful in Australian exploration in the last decade have all had magnetic moments, and sensitivities, which were one to two orders greater than those commonly used in North America. It is shown that frequency domain systems of the same sensitivity would require relative receivertransmitter alignment accuracies of better than one minute of arc which is impracticable in production geophysics. Time domain EM systems do not require such accuracy, and will become increasingly dominant in exploration throughout the world with the increasing need to explore at depth.

At altitudes greater than a few kilometers the horizon is indistinct because of contrast reduction, even on extraordinarily clear days. An airplane passenger flying over an ocean cannot point to the apparent boundary between earth and sky and confidently proclaim its distance. To determine the distance to the horizon to within 10% requires knowing its angular position to within a few minutes of arc. This is unattainable in a realistic atmosphere, even one that is very clean. Scattering by the air molecules themselves is not quite sufficient to blur the horizon, but it does not take many particles before the horizon becomes indistinct.

In this paper, we describe the three different detection systems for analysing gamma ray bursts, in the SIGMA experiment : 1. Image detection with 1.5 arc minute resolution 2. Search for optical counterparts to gamma ray bursts with star sensor images 3. Iog N-Log S analysis using the anticoincidence system.

The latency of the first (P1) and second (P2) major positive waves of the pattern reversal visual evoked potential (VEP) for small checks (15 minutes of arc) was measured in 68 visually normal children and 32 amblyopic children with mild to moderate visual acuity losses. In the normal children there were no P1 and P2 interocular latency differences. The amblyopic children showed longer P1 latencies and shorter P2 latencies in their amblyopic eye than their normal fellow eye. These findings can be accounted for by a selective loss of the contrast-specific evoked potential mechanisms in amblyopia. The 'shorter' P2 latency obtained from amblyopic eyes for small checks is a reflection of the luminance responses that are normally elicited by larger (60 minute) checks.

Binocular visual acuity of normal newborn infants, preterm newborn infants, and newborn, full-term infant patients with nonophthalmologic abnormalities was measured by means of grating acuity cards. Each test took about six minutes to complete, and 89% of the tests (154 of 174) were successful. Visual acuity of infants at 39 to 40 weeks of gestational age was about 0.023 stripes per minute of arc, or 0.69 cycles per degree (20/866). Between 34 and 44 weeks of gestational age, visual acuity improved at the rate of 0.46 octaves per month. This test is simple, fast, and reliable, and requires no apparatus except the cards themselves.

The investigation of the distribution of number densities and radial velocities in the Perseus cluster led us to the conclusion that this cluster possesses dominant substructures. This result is in agreement with a corresponding result for the Hydra-I cluster and with former conclusions of different authors that substructures are a typical phenomenon for a high percentage of all clusters of galaxies. The complex of the Perseus cluster has a diameter of 60–80 minutes of arc. Die Untersuchung der Anzahl-Dichte-Verteilung sowie der Verteilung der Radialgeschwindigkeiten im Perseus Haufen fuhrt uns zu dem Ergebnis, das dieser Haufen deutliche Unterstrukturen besitzt. Dieses Ergebnis steht in Einklang mit einem entsprechenden Ergebnis fur den Hydra-I Haufen und mit den Schlusfolgerungen verschiedener Autoren, das Unterstrukturen eine typische Erscheinung in einem grosen Prozentsatz aller Galaxienhaufen sind. Der Komplex des Perseus Haufens besitzt einen Durchmesser von 60–80 Bogenminuten.

Hong's model (1985) for the brightness behaviour of the Zodiacal Light has been applied to investigate the possibility of detecting an enhancement of intensity on the sunward side of Venus. It is shown that any detectable effect would not be observed beyond a few tenths of an arc minute from Venus, making it unlikely to be seen by the unaided eye.