The effect of training on reaction time

A visual enhancement training program utilizing the Eyespan was evaluated for its effect on reaction time (RT} and motor response time (MRT). The RT\u27s and MRT\u27s of 47 subjects were measured under identical conditions before and after a training program. Twenty four experimental subjects participated in a three week training program involving a minimum of 15 five minute sessions with the Eyespan. The other twenty three subjects served as the control for the study. After the training program, results indicated a significant improvement in RT\u27s and MRT\u27s of the experimental group in comparison to the control group. Since the effect of training with the Eyespan appears to be transferrable, it may be possible to improve athletic performance by improving RT\u27s and MRT\u27s through this type of visual enhancement therapy

African Americans and Appomattox Manor Within the Structured Landscape of the Eppes Plantation

The Civil War brought about many changes in Virginian society, including the area around City Point, Virginia. These changes greatly effected the manner in which plantation owners managed their farms. Plantation owners had to find new ways of obtaining and exploiting their labor, and protecting their resources. The goal of this report is to explore those changes between the years 1851 and 1872 on the Eppes' plantations. I examine how Dr. Eppes structured his landscape to aid in controlling his productive resources, and the relationship he held with African-Americans. Part of exploring that relationship will be examining the living conditions of African-Americans on the Eppes' plantations as slaves and freedmen laborers. Dr. Eppes' home, Appomattox Manor, and its grounds now make up the City Point Unit of the Petersburg National Battlefield. This report will place the City Point Unit into its larger historic context. Though the unit is best known as the location of General Grant's headquarters during the Siege of Petersburg, its history is far more extensive. In this report, I place City Point and Appomattox Manor in the plantation context which surrounded them before and after the war. It will show how the Civil War was not an isolated event, but was effected by and affected the social world around it

Pollen dimorphism and dioecy in Vitis aestivalis

Problems of low production and sterile pollen in varieties of Vitis vinifera may be tracable to their ancestral relations with dioecious wild grapes.Like V. riparia, the wild summer grape V. aestivalis has dimorphic male and female flowers; but unlike V. riparia it also has dimorphic pollen grains with the pollen from the female flower being significantly smaller.It seems fairly certain that V. aestivalis is truly dioecious

The Gamma-Ray Blazar Content of the Northern Sky

Using survey data, we have re-evaluated the correlation of flat spectrum radio sources with EGRET sources in the Northern sky. A likelihood analysis incorporating the radio and X-ray properties and the Gamma-ray source localization is used to gauge the reliability of associations and to search for counterparts of previously unidentified EGRET sources. Above |b|=10deg, where the classification is complete, we find that 70% of the Northern EGRET sources have counterparts similar to the bright EGRET blazars. For several of these we identify known blazar counterparts more likely than the earlier proposed 3EG association; for ~20 we have new identifications. Spectroscopic confirmation of these candidates is in progress and we have found flat spectrum radio quasars and BL Lac counterparts with redshifts as high as 4. We also find strong evidence for a set of 28 objects with no plausible counterpart like the known EGRET Blazars. These thus represent either a new extragalactic population or a population of Galactic objects with a large scale height. The survey has been extended into the plane, where we find several new blazar candidates; the bulk of the sources are, however, Galactic. Looking ahead to the GLAST era we predict that several of the present 3EG sources are composite and that higher resolution data will break these into multiple Blazar IDs.Comment: 13 pages, 6 figures, submitted to Ap

Lyman-alpha absorption around nearby galaxies

We have used STIS aboard HST to search for Lyman-alpha (Lya) absorption lines in the outer regions of eight nearby galaxies using background QSOs and AGN as probes. Lya lines are detected within a few hundred km/s of the systemic velocity of the galaxy in all cases. We conclude that a background line-of-sight which passes within 26-200 h-1 kpc of a foreground galaxy is likely to intercept low column density neutral hydrogen with log N(HI) >~ 13.0. The ubiquity of detections implies a covering factor of ~ 100% for low N(HI) gas around galaxies within 200 h-1 kpc. We discuss the difficulty in trying to associate individual absorption components with the selected galaxies and their neighbors, but show that by degrading our STIS data to lower resolutions, we are able to reproduce the anti-correlation of Lya equivalent width and impact parameter found at higher redshift. We also show that the equivalent width and column density of Lya complexes (when individual components are summed over ~ 1000 km/s) correlate well with a simple estimate of the volume density of galaxies brighter than M(B) = -17.5 at the same redshift as a Lya complex. We do not reject the hypothesis that the selected galaxies are directly responsible for the observed Lya lines, but our analysis indicates that absorption by clumpy intragroup gas is an equally likely explanation. (Abriged)Comment: Accepted for publication in Nov 20, 2002 issue of ApJ. Paper with all figures can be found at http://www.astro.princeton.edu/~dvb/lyapaper.ps (preferable). Minor typos fixe

Space Telescope Imaging Spectrograph slitless observations of Small Magellanic Cloud Planetary Nebulae: a study on morphology, emission line intensity, and evolution

A sample of 27 Planetary Nebulae (PNs) in the Small Magellanic Clouds (SMC) have been observed with the Hubble Space Telescope Imaging Spectrograph (HST/STIS) to determine their morphology, size, and the spatial variation of the ratios of bright emission lines. The morphologies of SMC PNs are similar to those of LMC and Galactic PNs. However, only a third of the resolved SMC PNs are asymmetric, compared to half in the LMC. The low metallicity environment of the SMC seems to discourage the onset of bipolarity in PNs. We measured the line intensity, average surface brightness (SB), and photometric radius of each nebula in halpha, hbeta, [O III] lambda4959 and 5007, [NII] 6548 and 6584, [S II] lambda6716 and 5731, He I 6678, and [OI] 6300 and 6363. We show that the surface brightness to radius relationship is the same as in LMC PNs, indicating its possible use as a distance scale indicator for Galactic PNs. We determine the electron densities and the ionized masses of the nebulae where the [S II] lines were measured accurately, and we find that the SMC PNs are denser than the LMC PNs by a factor of 1.5. The average ionized mass of the SMC PNs is 0.3 Msun. We also found that the median [O III]/hbeta intensity ratio in the SMC is about half than the corresponding LMC median. We use Cloudy to model the dependence of the [O III]/hbeta ratio on the oxygen abundance. Our models encompass very well the average observed physical quantities. We suggest that the SMC PNs are principally cooled by the carbon lines, making it hard to study their excitation based on the optical lines at our disposal.Comment: Accepted for publication in the Astrophysical Journal, 30 pages, 13 figures, 6 tables. For high resolution version of Figs 1 to 6, see http://archive.stsci.edu/hst/mcpn/home.htm