The Color Octet Effect from e+e−→J/ψ+X+γe^+ e^-\to{J/\psi}+X+\gamma at B Factory

We study the initial state radiation process $e^+ e^-\to{J/\psi}+X+\gamma$ for $J/\psi$ production at B factory, and find the cross section is 61% larger than it's Born one for color octet part and is about half as it's Born one for color singlet part. Furthermore, the color singlet and color octet signal are very clearly separated in it's $E_\gamma$ spectra due to kinematics difference. We suggest to measure this $E_\gamma$ spectra at B factory to determine the color octet effect.Comment: 4 pages, 4 figures and 1 tabl

The Limits of Reductionism in Medicine: Could Systems Biology Offer an Alternative?

In the first of a two part series, Ahn and colleagues discuss the reductionist approach pervading medicine and explain how a systems approach (as advocated by systems biology) may complement reductionism

Far-Ultraviolet Absorption Lines in the Remnant of SN 1006

We have obtained a far-ultraviolet spectrum (1150-1600 Å) of a hot subdwarf star behind the remnant of supernova 1006 with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope. The high-quality spectrum is used to test previous identifications of the strong absorption features discovered with the International Ultraviolet Explorer. These features have FWHM = 4000 (±300) km s-1 and are not at the rest wavelengths of known interstellar lines, as opposed to the broader (~8000 km s-1 FWHM) Fe II lines from the remnant centered at 0 km s-1 in near-UV FOS spectra. We confirm that the broad absorption features are principally due to redshifted Si II, Si III, and Si IV lines, which are centered at a radial velocity of 5100 (±200) km s-1. The Si II λ1260.4 profile is asymmetric, with a nearly flat core and sharp red wing, unlike the Si II λ1526.7 and Si IV λλ1393.8, 1402.8 profiles. One possible explanation is additional absorption from another species. Previous work has suggested that S II λλ1250.6, 1253.8, 1259.5 at a radial velocity of ~6000 km s-1 is responsible, but this would require a sulfur-to-silicon abundance ratio that is at least a factor of 10 higher than expected. Another possible explanation is that the Si II and Si IV profiles are intrinsically different, but this does not explain the symmetric (albeit weaker) Si II λ1526.7 profile

Far-UV Absorption Lines in the Remnant of SN 1006

We have obtained a far-ultraviolet spectrum (1150 - 1600 Ang.) of a hot subdwarf star behind the remnant of SN 1006 with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope. The high-quality spectrum is used to test previous identifications of the strong absorption features discovered with the International Ultraviolet Explorer. These features have FWHM = 4000 (+/- 300) km/sec and are not at the rest wavelengths of known interstellar lines, as opposed to the broader (8000 km/sec FWHM) Fe II lines from the remnant centered at zero km/sec in near-UV FOS spectra. We confirm that the broad absorption features are principally due to redshifted Si II, Si III, and Si IV lines, which are centered at a radial velocity of 5100 (+/- 200) km/sec. The Si II 1260.4 profile is asymmetric, with a nearly flat core and sharp red wing, unlike the Si II 1526.7 and Si IV 1393.8, 1402.8 profiles. One possible explanation is additional absorption from another species. Previous work has suggested that S II 1250.6, 1253.8, 1259.5 at a radial velocity of 6000 km/sec is responsible, but this would require a sulfur to silicon abundance ratio that is at least a factor of ten higher than expected. Another possible explanation is that the Si II and Si IV profiles are intrinsically different, but this does not explain the symmetric (albeit weaker) Si II 1526.7 profile.Comment: 17 pages, Latex, 2 postscript figures; to appear in ApJ (Letters

In Vivo Imaging Reveals Dendritic Targeting of Laminated Afferents by Zebrafish Retinal Ganglion Cells

SummaryTargeting of axons and dendrites to particular synaptic laminae is an important mechanism by which precise patterns of neuronal connectivity are established. Although axons target specific laminae during development, dendritic lamination has been thought to occur largely by pruning of inappropriately placed arbors. We discovered by in vivo time-lapse imaging that retinal ganglion cell (RGC) dendrites in zebrafish show growth patterns implicating dendritic targeting as a mechanism for contacting appropriate synaptic partners. Populations of RGCs labeled in transgenic animals establish distinct dendritic strata sequentially, predominantly from the inner to outer retina. Imaging individual cells over successive days confirmed that multistratified RGCs generate strata sequentially, each arbor elaborating within a specific lamina. Simultaneous imaging of RGCs and subpopulations of presynaptic amacrine interneurons revealed that RGC dendrites appear to target amacrine plexuses that had already laminated. Dendritic targeting of prepatterned afferents may thus be a novel mechanism for establishing proper synaptic connectivity

Effect of Pulsed or Continuous Delivery of Salt on Sensory Perception Over Short Time Intervals

Salt in the human diet is a major risk factor for hypertension and many countries have set targets to reduce salt consumption. Technological solutions are being sought to lower the salt content of processed foods without altering their taste. In this study, the approach was to deliver salt solutions in pulses of different concentrations to determine whether a pulsed delivery profile affected sensory perception of salt. Nine different salt profiles were delivered by a Dynataste device and a trained panel assessed their saltiness using time–intensity and single-score sensory techniques. The profile duration (15 s) was designed to match eating conditions and the effects of intensity and duration of the pulses on sensory perception were investigated. Sensory results from the profiles delivered in either water or in a bouillon base were not statistically different. Maximum perceived salt intensities and the area under the time– intensity curves correlated well with the overall perceived saltiness intensity despite the stimulus being delivered as several pulses. The overall saltiness scores for profiles delivering the same overall amount of sodium were statistically not different from one another suggesting that, in this system, pulsed delivery did not enhance salt perception but the overall amount of salt delivered in each profile did affect sensory perception

Perturbation of Retinoid Homeostasis Increases Malformation Risk in Embryos Exposed to Pregestational Diabetes

Funding. This work was supported by funding from Hong Kong Research Grants Council General Research Fund project reference 441606 and 474109 to A.S.W.S., Y.C.L., C.C.W., P.J.M. and A.J.C..Peer reviewedPostprin