Preliminary normative data for a new device to measure dynamic visual acuity

PURPOSE: Historically, dynamic visual acuity (OVA) measurement relied on instruments that presented a moving target at a high velocity that was gradually slowed until the subject could correctly identify it (head stable, target moving). This type of testing, however, bears little resemblance to typical OVA stimuli encountered in daily life. The purpose of this project is to introduce preliminary normative data for a new device using a stationary stimulus viewed during calibrated head movements to measure OVA. This condition is much more representative of the OVA tasks encountered in everyday life. METHODS: Fifty-four subjects aged 23-57 years were evaluated using the inVision™ system (NeuroCom® International, Inc.). The PC-based instrument presents a tumbling E stimulus when the subject achieves a given head movement velocity as monitored by a head-borne accelerometer. Subjects are instructed to move the head to and fro (as if to say no ) at differing velocities. When the target head velocity is reached, a tumbling E is presented on the computer monitor and the subject must make a forced choice regarding the orientation of the stimulus. Data were obtained for two protocols: OVA (head velocity is held constant and the stimulus size is gradually reduced) and gaze stabilization (stimulus size is held constant and head velocity is increased). RESULTS: The inVision™ system demonstrated excellent testability, all fifty-four subjects were able to complete both test protocols. With increasing age, there appears to be a trend toward decreasing performance, but no statistical significant differences were found. Further testing involving older subjects is needed to uncover more definite trends with age. When the data were analyzed by refractive category, high myopes (\u3e4.000) performed significantly poorer on the OVA test. There were no differences in this group based on static visual acuity, age, or type of correction. CONCLUSION: While the inVision™ system is currently being used mostly in vestibular/ENT cl inical settings, it offers intriguing potential for utilization in optometric science. Previous studies have shown that OVA performance cannot be predicted by other tests commonly used in optometric patient evaluations, and our results suggest the same. Hence, this instrument may provide a unique new assessment tool to aid the clinician in the diagnosis and management of visual conditions that cannot be quantified using static methods of visual assessment

Enforcement Evasion Highlights Need for Better Satellite‐Based Forest Governance

Our recent article, “Are Brazil’s Deforesters Avoiding Detection?” demonstrated that focusing illegal deforestation enforcement on the subset of forest monitored by the flagship PRODES system has caused PRODES to capture a declining share of deforestation in the Brazilian Amazon. Deforesters may be purposively seeking out forests not monitored for enforcement. Addressing the problem would help Brazil maintain a cutting‐edge forest governance model worthy of transfer to other nations. Two commentaries questioned our decision to investigate solely PRODES and not additional government monitoring systems. We focused on PRODES because it is the most salient deforestation monitoring system. Other key deforestation monitoring systems are all either limited to the same monitoring footprint as PRODES, not used for enforcement, or are rarely used for measuring forest loss in the Brazilian Amazon. We do agree with the commentaries that Brazil’s new satellite monitoring protocol for greenhouse gas emissions estimation is critical progress of the type we were advocating in our original article.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138285/1/conl12379_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138285/2/conl12379.pd

Egg-laying of salamanders

25 p. : ill. ; 24 cm.Includes bibliographical references (p. 24-25)

Magnetic iron oxide nanowires formed by reactive dewetting

The growth and reactive dewetting of ultra-thin films of iron oxides supported on Re(0001) surfaces have been imaged in-situ in real time. Initial growth forms a non-magnetic stable FeO (wüstite like) layer in a commensurate network upon which high aspect ratio nanowires of several microns length but less than 40nm width can be fabricated. The nanowires are closely aligned with the substrate crystallography and imaging by X-ray magnetic circular dichroism shows that each contain a single magnetic domain. The driving force for dewetting appears to be the minimization of strain energy of the Fe3O4 crystallites and follows the Tersoff and Tromp model in which strain is minimized at constant height by extending in one epitaxially matched direction. Such wires are promising in spintronic applications and we predict that the growth will also occur on other hexagonal substrates

How does the radio enhancement of broad absorption line quasars relate to colour and accretion rate?

The origin of radio emission in different populations of radio-quiet quasars is relatively unknown, but recent work has uncovered various drivers of increased radio-detection fraction. In this work, we pull together three known factors: optical colour (g - i), C IV distance (a proxy for L/LEdd), and whether or not the quasar contains broad absorption lines (BALQSOs) which signify an outflow. We use SDSS (Sloan Digital Sky Survey) DR14 spectra along with the LOFAR Two Metre Sky Survey Data Release 2 and find that each of these properties have an independent effect. BALQSOs are marginally more likely to be radio-detected than non-BALQSOs at similar colours and L/LEdd, moderate reddening significantly increases the radio-detection fraction and the radio detection increases with L/LEdd above a threshold for all populations. We test a widely used simple model for radio wind shock emission and calculate energetic efficiencies that would be required to reproduce the observed radio properties. We discuss interpretations of these results concerning radio-quiet quasars more generally. We suggest that radio emission in BALQSOs is connected to a different physical origin than the general quasar population since they show different radio properties independent of colour and C IV distance

The Origins of a Rich Absorption Line Complex in a Quasar at Redshift 3.45

We discuss the nature and origin of a rich complex of narrow absorption lines in the quasar J102325.31+514251.0 at redshift 3.447. We measure nine C IV(\lambda1548,1551) absorption line systems with velocities from -1400 to -6200 km/s, and full widths at half minimum ranging from 16 to 350 km/s. We also detect other absorption lines in these systems, including H I, C III, N V, O VI, and Si IV. Lower ionisation lines are not present, indicating a generally high degree of ionisation in all nine systems. The total hydrogen column densities range from <=10^{17.2} to 10^{19.1}cm^{-2}. We examine several diagnostics to estimate more directly the location and origin of each absorber. Four of the systems can be attributed to a quasar-driven outflow based on line profiles that are smooth and broad compared to thermal line widths. Several systems also have other indicators of a quasar outflow origin, including partial covering. Altogether there is direct evidence for 6 of the 9 systems forming in a quasar outflow. Consistent with a near-quasar origin, eight of the systems have metallicity values or lower limits in the range Z >= 1-8 Z_{sun}. The lowest velocity system, which has an ambiguous location, also has the lowest metallicity, Z <= 0.3 Z_{sun}, and might form in a non-outflow environment farther from the quasar. Overall, however, this complex of narrow absorption lines can be identified with a highly structured, multi-component outflow from the quasar. The high metallicities are similar to those derived for other quasars at similar redshifts and luminosities, and are consistent with evolution scenarios wherein quasars appear after the main episodes of star formation and metal enrichment in the host galaxies.Comment: 16 pages, 12 figures, Accepted to MNRAS, July 201

Prospectus, September 21, 1983

CONSTRUCTION PROGRESSES; Manager runs unique Hardee\u27s; Elect your senator Sept. 21-22; Prisons pursue harsher sentencing; Student admits scary reality; Mr. Roberts: never a water shortage; StuGo elections held this week; Paxton- town of peace ; Working women ignored in many countries; Rape affects into past; Pregnancy problem for teenagers; Dress for success; Segregation exists-- progress is little; Classified; Stu-Go happenings; Produce prices will be stable; Rockabilly E.B.\u27s are Movin\u27 Up ; Campus Paperback Bestsellers; New & Recommended; Ballet Nacional Español to be at Assembly Hall; Stray Cats definitely strut; Crenshaw\u27s Field Day; UI Ticket Exchange Area designated; Gym guidelines; Henkels looks to volleyball nationals; Fast Freddy Contest; Traffic Changes for UI footballhttps://spark.parkland.edu/prospectus_1983/1010/thumbnail.jp

Metallicity and Far-Infrared Luminosity of High Redshift Quasars

We present the results of an exploratory study of broad line region (BLR) metallicity in 34 2.2 < z < 4.6 quasars with far-infrared (FIR) luminosities (L_FIR) from 10^13.4 to 10^12.1 L_\odot . Quasar samples sorted by L_FIR might represent an evolutionary sequence if the star formation rates (SFRs) in quasar hosts generally diminish across quasar lifetimes. We use rest-frame ultraviolet spectra from the Sloan Digital Sky Survey to construct three composite spectra sorted by L_FIR, corresponding to average SFRs of 4980, 2130 and 340 M_\odot yr^-1 after correcting for a nominal quasar FIR contribution. The measured N V {\lambda} 1240/C IV {\lambda} 1550 and Si IV {\lambda} 1397+O IV] {\lambda} 1402/C IV {\lambda} 1550 emission line ratios indicate super-solar BLR metallicities in all three composites, with no evidence for a trend with the star formation rate. The formal derived metallicities, Z ~ 5-9 Z_\odot , are similar to those derived for the BLRs of other quasars at similar redshifts and luminosities. These results suggest that the ongoing star formation in the host is not responsible for the metal enrichment of the BLR gas. Instead, the BLR gas must have been enriched before the visible quasar phase. These results for high quasar metallicities, regardless of L_FIR, are consistent with evolution scenarios wherein visibly bright quasars appear after the main episode(s) of star formation and metal enrichment in the host galaxies. Finally, young quasars, those more closely associated with a recent merger or a blowout of gas and dust, may exhibit tracers of these events, such as redder continuum slopes and higher incidence of narrow absorption lines. With the caveat of small sample sizes, we find no relation between L_FIR and the reddening or the incidence of absorption lines.Comment: 10 pages, 3 figures. Accepted to MNRAS, May 201