600 research outputs found
When Walls are No Longer Barriers: Perception of Wall Height in Parkour
Through training, skilled parkour athletes (traceurs) overcome everyday obstacles, such as walls, that are typically insurmountable. Traceurs and untrained novices estimated the height of walls and reported their anticipated ability to climb the wall. The traceurs perceived the walls as shorter than did novices. This result suggests that perception is scaled by the perceiver’s anticipated ability to act, and is consistent with the action-specific account of perception
Action-Specific Effects Underwater
Action-specific effects on perception are apparent in terrestrial environments. For example, targets that require more effort to walk, jump, or throw to look farther away than when the targets require less effort. Here, we examined whether action-specific effects would generalize to an underwater environment. Instead, perception might be geometrically precise, rather than action-specific, in an environment that is novel from an evolutionary perspective. We manipulated ease to swim by giving participants swimming flippers or taking them away. Those who estimated distance while wearing the flippers judged underwater targets to be closer than did participants who had taken them off. In addition, participants with better swimming ability judged the targets to be closer than did those with worse swimming ability. These results suggest perceived distance underwater is a function of the perceiver’s ability to swim to the targets
Stories in Song : Voice Faculty Recital
The talented members of the KSU voice faculty present a special recital with the works of Britten, Schubert, and Schumann. Featured Faculty artists include: Todd Wedge, Heather Witt, Jana Young, and Dr.s Nathan Munson and Eric Jenkins.https://digitalcommons.kennesaw.edu/musicprograms/2307/thumbnail.jp
Imaging a Quasar Accretion Disk with Microlensing
We show how analysis of a quasar high-magnification microlensing event may be
used to construct a map of the frequency-dependent surface brightness of the
quasar accretion disk. The same procedure also allows determination of the disk
inclination angle, the black hole mass (modulo the caustic velocity), and
possibly the black hole spin. This method depends on the validity of one
assumption: that the optical and ultraviolet continuum of the quasar is
produced on the surface of an azimuthally symmetric, flat equatorial disk,
whose gas follows prograde circular orbits in a Kerr spacetime (and plunges
inside the marginally stable orbit). Given this assumption, we advocate using a
variant of first-order linear regularization to invert multi-frequency
microlensing lightcurves to obtain the disk surface brightness as a function of
radius and frequency. The other parameters can be found by minimizing
chi-square in a fashion consistent with the regularized solution for the
surface brightness.
We present simulations for a disk model appropriate to the Einstein Cross
quasar, an object uniquely well-suited to this approach. These simulations
confirm that the surface brightness can be reconstructed quite well near its
peak, and that there are no systematic errors in determining the other model
parameters. We also discuss the observational requirements for successful
implementation of this technique.Comment: accepted to ApJ for publicatio
Non-obstructive azoospermia and maturation arrest with complex translocation 46,XY t(9;13;14)(p22;q21.2;p13) is consistent with the Luciani-Guo hypothesis of latent aberrant autosomal regions and infertility
OBJECTIVE: To describe clinical and histological features observed in the setting of an unusual complex translocation involving three autosomes (9, 13, and 14) identified in an otherwise healthy male referred for infertility consultation. MATERIALS AND METHODS: The patient was age 30 and no family history was available (adopted). Total azoospermia was confirmed on multiple semen analyses. Peripheral karyotype showed a 46,XY t(9;13;14)(p22:q21.2;p13) genotype; no Y-chromosome microdeletions were identified. Cystic fibrosis screening was negative. Bilateral testis biopsy revealed uniform maturation arrest and peritubular fibrosis. RESULTS: Formal genetic counseling was obtained and the extant literature reviewed with the couple. Given the low probability of obtaining sperm on testicular biopsy, as well as the high risk of any retrieved sperm having an unbalanced genetic rearrangement, the couple elected to proceed with fertility treatment using anonymous donor sperm for insemination. CONCLUSION: Although genes mapped to the Y-chromosome have been established as critical to normal testicular development and spermatogenesis, certain autosomal genes are now also recognized as important in these processes. Here we present clinical evidence to support the Luciani-Guo hypothesis (first advanced in 1984 and refined in 2002), which predicts severe spermatogenic impairment with aberrations involving chromosomes 9, 13, and/or 14, independent of Y-chromosome status. Additional study including fluorescent in situ hybridization and molecular analysis of specific chromosomal regions is needed to characterize more fully the contribution(s) of these autosomes to male testicular development and spermatogenesis
Observation of the Far-ultraviolet Continuum Background with SPEAR/FIMS
We present the general properties of the far-ultraviolet (FUV; 1370-1720A)
continuum background over most of the sky, obtained with the Spectroscopy of
Plasma Evolution from Astrophysical Radiation instrument (SPEAR, also known as
FIMS), flown aboard the STSAT-1 satellite mission. We find that the diffuse FUV
continuum intensity is well correlated with N_{HI}, 100 m, and H-alpha
intensities but anti-correlated with soft X-ray. The correlation of the diffuse
background with the direct stellar flux is weaker than the correlation with
other parameters. The continuum spectra are relatively flat. However, a weak
softening of the FUV spectra toward some sight lines, mostly at high Galactic
latitudes, is found not only in direct-stellar but also in diffuse background
spectra. The diffuse background is relatively softer that the direct stellar
spectrum. We also find that the diffuse FUV background averaged over the sky
has about the same level as the direct-stellar radiation field in the
statistical sense and a bit softer spectrum compared to direct stellar
radiation. A map of the ratio of 1400-1510A to 1560-1660A shows that the sky is
divided into roughly two parts. However, this map shows a lot of patchy
structures on small scales. The spatial variation of the hardness ratio seems
to be largely determined by the longitudinal distribution of spectral types of
stars in the Galactic plane. A correlation of the hardness ratio with the FUV
intensity at high intensities is found but an anti-correlation at low
intensities. We also find evidence that the FUV intensity distribution is
log-normal in nature.Comment: 39 pages, 26 figures, accepted for publication in ApJ
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Sex Hormone-Binding Globulin Levels Are Inversely Associated With Nonalcoholic Fatty Liver Disease in HIV-Infected and -Uninfected Men.
BackgroundNonalcoholic fatty liver disease (NAFLD) is a leading cause of liver disease worldwide. Elevated sex hormone-binding globulin (SHBG) levels have been observed in the setting of HIV and may protect against some metabolic disorders. We aimed to investigate whether higher SHBG levels may protect against NAFLD in men with/without HIV.MethodsNAFLD was assessed using noncontrast computed tomography in 530 men in the Multicenter AIDS Cohort Study (MACS) who drank <3 alcoholic drinks/d and were uninfected with chronic hepatitis C or B (340HIV+, 190HIV-). Morning serum samples were tested for SHBG, total testosterone (TT), and adiponectin. Multivariable logistic regression was used to assess associations between HIV, SHBG, TT, adiponectin, and NAFLD.ResultsMedian SHBG was highest among HIV+/NAFLD- men and lowest among HIV-/NAFLD+ men. Adjusted for demographics, HIV, visceral adiposity, HOMA-IR, TT, and PNPLA3 genotype, higher SHBG was associated with lower odds of NAFLD (odds ratio [OR], 0.52 per doubling; 95% confidence interval [CI], 0.34-0.80). In separate multivariable models without SHBG, HIV (OR, 0.46; 95% CI, 0.26-0.79) and higher adiponectin (OR, 0.66 per doubling; 95% CI, 0.49-0.89) were associated with lower NAFLD odds, whereas TT was not significantly associated (OR, 0.74 per doubling; 95% CI, 0.53-1.04). Adjusting for SHBG attenuated the associations of HIV (OR, 0.61; 95% CI, 0.34-1.08) and adiponectin (OR, 0.74; 95% CI, 0.54-1.02) with NAFLD.ConclusionsSHBG levels were higher among HIV+ men, were independently associated with lower NAFLD, and could partially explain the associations of HIV and higher adiponectin with lower NAFLD in our cohort. These findings suggest that SHBG may protect against NAFLD, supporting further prospective and mechanistic studies
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