The effect of ultradian and orbital cycles on plant growth

In a series of experiments using sugar beets, researchers investigated the effects of varying cycles lengths on growth (0.37 hr to 48 hr). Each cycle was equally divided into a light and dark period so that each treatment regardless of cycle length received the same amount of light over the 17 weeks of the experiment. Two growth parameters were used to evaluate the effects of cycle length, total fresh weight and sucrose content of the storage root. Both parameters showed very similar responses in that under long cycles (12 hr or greater) growth was normal, whereas plants growing under shorter cycle periods were progressively inhibited. Minimum growth occurred at a cycle period of 0.75 hr. The yield at the 0.75 hr cycle, where was at a minimum, for total fresh weight was only 51 percent compared to the 24 hr cycle. The yield of sucrose was even more reduced at 41 percent of the 24 hr cycle

Small-mass effects in heavy-to-light form factors

We present the heavy-to-light form factors with two different non-vanishing masses at next-to-next-to-leading order and study its expansion in the small mass. The leading term of this small-mass expansion leads to a factorized expression for the form factor. The presence of a second mass results in a new feature, in that the soft contribution develops a factorization anomaly. This cancels with the corresponding anomaly in the collinear contribution. With the generalized factorization presented here, it is possible to obtain the leading small-mass terms for processes with large masses, such as muon-electron scattering, from the corresponding massless amplitude and the soft contribution.Comment: 20 pages, 4 figures, 1 ancillary file, published versio

Electron-beam-sustained discharge revisited - light emission from combined electron beam and microwave excited argon at atmospheric pressure

A novel kind of electron beam sustained discharge is presented in which a 12keV electron beam is combined with a 2.45GHz microwave power to excite argon gas at atmospheric pressure in a continuous mode of operation. Optical emission spectroscopy is performed over a wide wavelength range from the vacuum ultraviolet (VUV) to the near infrared (NIR). Several effects which modify the emission spectra compared to sole electron beam excitation are observed and interpreted by the changing plasma parameters such as electron density, electron temperature and gas temperature.Comment: 10 pages, 9 figure

Anisotropic flow and jet quenching in ultra-relativistic U+U collisions

Full-overlap U+U collisions provide significantly larger initial energy densities at comparable spatial deformation, and significantly larger deformation and volume at comparable energy density, than semicentral Au+Au collisions. We show quantitatively that this provides a long lever arm for studying the hydrodynamic behavior of elliptic flow in much larger and denser collision systems and the predicted non-linear path-length dependence of radiative parton energy loss.Comment: 4 pages, incl. 5 figures. First figure of v1 removed due to space limitations. Title changed by journal request. Minor other changes and a few references added or updated. This version accepted by Physical Review Letter

Methylation Status of Imprinted Genes and Repetitive Elements in Sperm DNA from Infertile Males

Stochastic, environmentally and/or genetically induced disturbances in the genome-wide epigenetic reprogramming processes during male germ-cell development may contribute to male infertility. To test this hypothesis, we have studied the methylation levels of 2 paternally (H19 and GTL2) and 5 maternally methylated (LIT1, MEST, NESPAS, PEG3, and SNRPN) imprinted genes, as well as of ALU and LINE1 repetitive elements in 141 sperm samples, which were used for assisted reproductive technologies (ART), including 106 couples with strictly male-factor or combined male and female infertility and 28 couples with strictly female-factor infertility. Aberrant methylation imprints showed a significant association with abnormal semen parameters, but did not seem to influence ART outcome. Repeat methylation also differed significantly between sperm samples from infertile and presumably fertile males. However, in contrast to imprinted genes, ALU methylation had a significant impact on pregnancy and live-birth rate in couples with male-factor or combined infertility. ALU methylation was significantly high-er in sperm samples leading to pregnancy and live-birth than in those that did not. Sperm samples leading to abortions showed significantly lower ALU methylation levels than those leading to the birth of a baby. Copyright (C) 2011 S. Karger AG, Base

Characteristics of Magnetohydrodynamic Oscillations Observed with Michelson Doppler Imager

We report on the spatial distribution of magnetogram oscillatory power and phase angles between velocity and magnetogram signals as observed with the Michelson Doppler Imager. The dataset is 151.25 arcsec times 151.25 arcsec containing sunspot from Dec 2, 1997 with a temporal sampling interval of 60 seconds and spatial sampling of 0.605 arcsec. Simultaneously observed continuum intensity and surface velocity accompany the magnetic information. We focus on three frequency regimes: 0.5-1.0, 3.0-3.5 and 5.5-6.0 mHz corresponding roughly to timescales of magnetic evolution, p-modes and the 3 minute resonant sunspot oscillation. Significant low frequency magnetogram power is found in lower flux pixels, 100-300 Gauss, in a striking ring with filamentary structure surrounding sunspot. Five minute magnetogram power peaks in extended regions of flux 600-800 Gauss. The 3 minute oscillation is observed in sunspot umbra in pixels whose flux measures 1300-1500 Gauss. Phase angles of approximately -90 degrees between velocity and magnetic flux in the 3.0-3.5 and 5.5-6.0 mHz regimes are found in regions of significant cross amplitude.Comment: 4 Pages, 4 Figures -- For better Figure files see: http://www.astro.ucla.edu/~norton/pub_list.htm