146 research outputs found
Telgo323: an H.323 Bridge for deaf telephony
We have developed a prototype bridge that relays text and speech between Teldem, a text telephone for the Deaf, and a standard telephone or H.323 endpoint. Telgo323 uses modified H.323 media gateways and open source Text to Speech and Speech to Text software. The approach allows for easy integration of new tools as the technologies mature. This paper presents the design of the implementation prototype, discusses Teldem tone decoding, and suggests directions for future work. The Telgo323 provides evidence that an automated relay bridge is imminently viable for the Deaf Community, and further demonstrates an attractive approach for building bridges over the Digital Divide.Telkom, Siemens, THRIPDepartment of HE and Training approved lis
Cross-cultural effects of color, but not morphological masculinity, on perceived attractiveness of men's faces
This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 ElsevierMuch attractiveness research has focused on face shape. The role of masculinity (which for adults is thought to be a relatively stable shape cue to developmental testosterone levels) in male facial attractiveness has been examined, with mixed results. Recent work on the perception of skin color (a more variable cue to current health status) indicates that increased skin redness, yellowness, and lightness enhance apparent health. It has been suggested that stable cues such as masculinity may be less important to attractiveness judgments than short-term, more variable health cues. We examined associations between male facial attractiveness, masculinity, and skin color in African and Caucasian populations. Masculinity was not found to be associated with attractiveness in either ethnic group. However, skin color was found to be an important predictor of attractiveness judgments, particularly for own-ethnicity faces. Our results suggest that more plastic health cues, such as skin color, are more important than developmental cues such as masculinity. Further, unfamiliarity with natural skin color variation in other ethnic groups may limit observers' ability to utilize these color cues
The Metagalactic Ionizing Radiation Field at Low Redshift
We compute the ionizing radiation field at low redshift, arising from
Seyferts, QSOs, and starburst galaxies. This calculation combines recent
Seyfert luminosity functions, extrapolated ultraviolet fluxes from our IUE-AGN
database, and a new intergalactic opacity model based on Hubble Space Telescope
and Keck Ly-alpha absorber surveys. At z = 0 for AGN only, our best estimate
for the specific intensity at 1 Ryd is I_0 = 1.3 (+0.8/-0.5) x 10^-23
ergs/cm^2/s/Hz/sr, independent of H_0, Omega_0, and Lambda. The one-sided
ionizing photon flux is Phi_ion = 3400 (+2100/-1300) photons/cm^2/s, and the H
I photoionization rate is Gamma_HI = 3.2 (+2.0/-1.2) x 10^-14 s^-1 for alpha_s
= 1.8. We also derive Gamma_ HI for z = 0 - 4. These error ranges reflect
uncertainties in the spectral indexes for the ionizing EUV (alpha_s = 1.8 +/-
0.3) and the optical/UV (alpha_UV = 0.86 +/- 0.05), the IGM opacity model, the
range of Seyfert luminosities (0.001 - 100 L*) and the completeness of the
luminosity functions. Our estimate is a factor of three lower than the most
stringent upper limits on the ionizing background (Phi_ion < 10^4
photons/cm^2/s) obtained from H-alpha observations in external clouds, and it
lies within the range implied by other indirect measures. Starburst galaxies
with a sufficiently large Lyman continuum escape fraction, f_ esc > 0.05, may
provide a comparable background to AGN, I_0 (z=0) = 1.1 (+1.5/-0.7) x 10^{-23).
An additional component of the ionizing background of this magnitude would
violate neither upper limits from H-alpha observations nor the acceptable range
from other measurements.Comment: 30 pages, 9 figures, accepted for Astronomical J. (Oct. 1999
Spatial proteomics finds CD155 and Endophilin-A1 as mediators of growth and invasion in medulloblastoma
The composition of the plasma membrane (PM)-associated proteome of tumor cells determines cell-cell and cell-matrix interactions and the response to environmental cues. Whether the PM-associated proteome impacts the phenotype of Medulloblastoma (MB) tumor cells and how it adapts in response to growth factor cues is poorly understood. Using a spatial proteomics approach, we observed that hepatocyte growth factor (HGF)-induced activation of the receptor tyrosine kinase c-MET in MB cells changes the abundance of transmembrane and membrane-associated proteins. The depletion of MAP4K4, a pro-migratory effector kinase downstream of c-MET, leads to a specific decrease of the adhesion and immunomodulatory receptor CD155 and of components of the fast-endophilin-mediated endocytosis (FEME) machinery in the PM-associated proteome of HGF-activated MB cells. The decreased surface expression of CD155 or of the fast-endophilin-mediated endocytosis effector endophilin-A1 reduces growth and invasiveness of MB tumor cells in the tissue context. These data thus describe a novel function of MAP4K4 in the control of the PM-associated proteome of tumor cells and identified two downstream effector mechanisms controlling proliferation and invasiveness of MB cells
Developing defined substrates for stem cell culture and differentiation
Over the past few decades, a variety of different reagents for stem cell maintenance and differentiation have been commercialized. These reagents share a common goal in facilitating the manufacture of products suitable for cell therapy while reducing the amount of non-defined components. Lessons from developmental biology have identified signalling molecules that can guide the differentiation process in vitro, but less attention has been paid to the extracellular matrix used. With the introduction of more biologically relevant and defined matrices, that better mimic specific cell niches, researchers now have powerful resources to fine-tune their in vitro differentiation systems, which may allow the manufacture of therapeutically relevant cell types. In this review article, we revisit the basics of the extracellular matrix, and explore the important role of the cell âmatrix interaction. We focus on laminin proteins because they help to maintain pluripotency and drive cell fate specification. This article is part of the theme issue âDesigner human tissue: coming to a lab near youâ
Changes in salivary estradiol predict changes in womenâs preferences for vocal masculinity
Although many studies have reported that womenâs preferences for masculine physical characteristics in men change systematically during the menstrual cycle, the hormonal mechanisms underpinning these changes are currently poorly understood. Previous studies investigating the relationships between measured hormone levels and womenâs masculinity preferences tested only judgments of menâs facial attractiveness. Results of these studies suggested that preferences for masculine characteristics in menâs faces were related to either womenâs estradiol or testosterone levels. To investigate the hormonal correlates of within-woman variation in masculinity preferences further, here we measured 62 womenâs salivary estradiol, progesterone, and testosterone levels and their preferences for masculine characteristics in menâs voices in five weekly test sessions. Multilevel modeling of these data showed that changes in salivary estradiol were the best predictor of changes in womenâs preferences for vocal masculinity. These results complement other recent research implicating estradiol in womenâs mate preferences, attention to courtship signals, sexual motivation, and sexual strategies, and are the first to link womenâs voice preferences directly to measured hormone levels
Symmetry and sexual dimorphism in human faces: interrelated preferences suggest both signal quality
Symmetry and masculinity in human faces have been proposed to be cues to the quality of the owner. Accordingly, symmetry is generally found attractive in male and female faces and femininity is attractive in female faces. Womenâs preferences for male facial masculinity vary in ways that may maximise genetic benefits to womenâs offspring. Here we examine same- and opposite-sex preferences for both traits (Study 1) and intercorrelations between preferences for symmetry and sexual dimorphism in faces (Study 1, Study 2) using computer manipulated faces. For symmetry, we found that male and female judges preferred symmetric faces more when judging faces of the opposite-sex than when judging same-sex faces. A similar pattern was seen for sexual dimorphism (i.e. women preferred more masculine male faces than men did), but women also showed stronger preferences for femininity in female faces than men reported. This suggests that women are more concerned with female femininity than are men. We also found that in women preferences for symmetry were positively correlated with preferences for masculinity in male faces and that in men preferences for symmetry were positively correlated with preferences for femininity in female faces. These latter findings suggest that symmetry and sexual dimorphism advertise a common quality in faces or that preferences for these facial cues are dependent on a common quality in the judges. Collectively, our findings support the view that preferences for symmetry and sexual dimorphism are related to mechanisms involved in sexual selection and mate choice rather than functionless by-products of other perceptual mechanisms
Changes in salivary estradiol predict changes in womenâs preferences for vocal masculinity
Although many studies have reported that womenâs preferences for masculine physical characteristics in men change systematically during the menstrual cycle, the hormonal mechanisms underpinning these changes are currently poorly understood. Previous studies investigating the relationships between measured hormone levels and womenâs masculinity preferences tested only judgments of menâs facial attractiveness. Results of these studies suggested that preferences for masculine characteristics in menâs faces were related to either womenâs estradiol or testosterone levels. To investigate the hormonal correlates of within-woman variation in masculinity preferences further, here we measured 62 womenâs salivary estradiol, progesterone, and testosterone levels and their preferences for masculine characteristics in menâs voices in five weekly test sessions. Multilevel modeling of these data showed that changes in salivary estradiol were the best predictor of changes in womenâs preferences for vocal masculinity. These results complement other recent research implicating estradiol in womenâs mate preferences, attention to courtship signals, sexual motivation, and sexual strategies, and are the first to link womenâs voice preferences directly to measured hormone levels
The End of the Rainbow: What Can We Say About the Extragalactic Sub-Megahertz Radio Sky?
The Galactic disc is opaque to radio waves from extragalactic sources with
frequencies nu less than ~3 MHz. However, radio waves with kHz, Hz, and even
lower frequencies may propagate through the intergalactic medium (IGM). I argue
that the presence of these waves can be inferred by using the Universe as our
detector. I discuss possible sub-MHz sources and set new non-trivial upper
limits on the energy density of sub-MHz radio waves in galaxy clusters and the
average cosmic background. Limits based on five effects are considered: (1)
changes in the expansion of the Universe from the radiation energy density (2)
heating of the IGM by free-free absorption; (3) radiation pressure squeezing of
IGM clouds by external radio waves; (4) synchrotron heating of electrons in
clusters; and (5) Inverse Compton upscattering of sub-MHz radio photons. Any
sub-MHz background must have an energy density much smaller than the CMB at
frequencies below 1 MHz. The free-free absorption bounds from the Lyman-alpha
forest are potentially the strongest, but are highly dependent on the
properties of sub-MHz radio scattering in the IGM. I estimate an upper limit of
6 * 10^4 L_sun Mpc^-3 for the emissivity within Lyman-alpha forest clouds in
the frequency range 5 - 200 Hz. The sub-MHz energy density in the Coma cluster
is constrained to be less than ~10^-15 erg cm^-3. At present, none of the
limits is strong enough to rule out a maximal T_b = 10^12 K sub-MHz synchrotron
background, but other sources may be constrained with a better knowledge of
sub-MHz radio propagation in the IGM.Comment: Accepted by MNRAS, 4 figures, 20 pages
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