Oxygen minimum zone expansion in the eastern tropical North Pacific during deglaciation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95396/1/grl21420.pd

Registration of N614, A3N615, N616, and N617 Shattercane Genetic Stocks with Cytoplasmic or Nuclear Male Sterility and Juicy or Dry Midribs

Four shattercane [Sorghum bicolor subsp. drummondii (Nees ex Steud.) de Wet ex Davidse] genetic stocks—N614 (Reg. No. GS-652, PI 665684), A3N615 (Reg. No. GS-651, PI 665683), N616 (Reg. No. GS-653, PI 665685), and N617 (Reg. No. GS-654, PI 665686)—with A3 cytoplasmic male sterility or the nuclear male sterility gene ms3 containing either juicy (dd) or dry (DD) culms were developed jointly by the USDA-ARS; the Iowa Agricultural and Home Economics Experiment Station, College of Agriculture and Life Sciences, Iowa State University; and the Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska. The stocks were released in July 2011. The source material for these genetic stocks was isolated from an archetypical shattercane population found near Lincoln, NE. Release of these genetic stocks makes available shattercane lines with both A3 cytoplasmic male sterility, and ms3 genetic (nuclear) male sterility to facilitate crossing. These genetic stocks also contain juicy (dd) or dry (DD) culms, a visible genetic marker to facilitate screening progeny resulting from crosses. The genetic stocks have immediate application for basic research involving gene flow from cultivated sorghum [Sorghum bicolor (L.) Moench] to shattercane and on the fitness of offspring resulting from such crosses

Inducing spin-dependent tunneling to probe magnetic correlations in optical lattices

We suggest a simple experimental method for probing antiferromagnetic spin correlations of two-component Fermi gases in optical lattices. The method relies on a spin selective Raman transition to excite atoms of one spin species to their first excited vibrational mode where the tunneling is large. The resulting difference in the tunneling dynamics of the two spin species can then be exploited, to reveal the spin correlations by measuring the number of doubly occupied lattice sites at a later time. We perform quantum Monte Carlo simulations of the spin system and solve the optical lattice dynamics numerically to show how the timed probe can be used to identify antiferromagnetic spin correlations in optical lattices.Comment: 5 pages, 5 figure

High-field vortices in Josephson junctions with alternating critical current density

We study long Josephson junctions with the critical current density alternating along the junction. New equilibrium states, which we call the field synchronized or FS states, are shown to exist if the applied field is from narrow intervals centered around equidistant series of resonant fields, $H_m$. The values of $H_m$ are much higher than the flux penetration field, $H_s$. The flux per period of the alternating critical current density, $\phi_i$, is fixed for each of the FS states. In the $m$-th FS state the value of $\phi_i$ is equal to an integer amount of flux quanta, $\phi_i =m\phi_0$. Two types of single Josephson vortices carrying fluxes $\phi_0$ or/and $\phi_0/2$ can exist in the FS states. Specific stepwise resonances in the current-voltage characteristics are caused by periodic motion of these vortices between the edges of the junction.Comment: 4 pages, 5 figure

Preparation of ultracold atom clouds at the shot noise level

We prepare number stabilized ultracold clouds through the real-time analysis of non-destructive images and the application of feedback. In our experiments, the atom number ${N\sim10^6}$ is determined by high precision Faraday imaging with uncertainty $\Delta_N$ below the shot noise level, i.e., $\Delta_N <\sqrt{N}$. Based on this measurement, feedback is applied to reduce the atom number to a user-defined target, whereupon a second imaging series probes the number stabilized cloud. By this method, we show that the atom number in ultracold clouds can be prepared below the shot noise level.Comment: Main text: 4 Figures, 4 pages. Supplemental Information: 4 figures, 5 page

Antiferromagnetic noise correlations in optical lattices

We analyze how noise correlations probed by time-of-flight (TOF) experiments reveal antiferromagnetic (AF) correlations of fermionic atoms in two-dimensional (2D) and three-dimensional (3D) optical lattices. Combining analytical and quantum Monte Carlo (QMC) calculations using experimentally realistic parameters, we show that AF correlations can be detected for temperatures above and below the critical temperature for AF ordering. It is demonstrated that spin-resolved noise correlations yield important information about the spin ordering. Finally, we show how to extract the spin correlation length and the related critical exponent of the AF transition from the noise.Comment: 4 pages, 4 figure

Spin dynamics in a two dimensional quantum gas

We have investigated spin dynamics in a 2D quantum gas. Through spin-changing collisions, two clouds with opposite spin orientations are spontaneously created in a Bose-Einstein condensate. After ballistic expansion, both clouds acquire ring-shaped density distributions with superimposed angular density modulations. The density distributions depend on the applied magnetic field and are well explained by a simple Bogoliubov model. We show that the two clouds are anti-correlated in momentum space. The observed momentum correlations pave the way towards the creation of an atom source with non-local Einstein-Podolsky-Rosen entanglement.Comment: 5 pages, 4 figure

Occurrence of the Waxy Alleles \u3ci\u3ewxa\u3c/i\u3e and \u3ci\u3ewxb\u3c/i\u3e in Waxy Sorghum Plant Introductions and Their Effect on Starch Thermal Properties

The existence of two waxy alleles, wxa associated with no detectable granule bound starch synthase (GBSS) and wxb associated with apparently inactive GBSS, was recently reported in sorghum [Sorghum bicolor (L.) Moench]. In this paper, the occurrence of the wxa and wxb alleles in the USDA-ARS photoperiod-insensitive sorghum collection was determined, and the effects of the wxa and wxballeles on thermal properties of sorghum starch (gelatinization temperatures and energy requirements) measured by differential scanning calorimetry. Of the 51 purported waxy accessions examined, 14 tested positive for presence of amylose by iodine staining and were considered to be previously misclassified wild type lines. Nine accessions were mixed for presence or absence of amylose. Twenty-four of the 28 accessions confirmed to be waxy by negative iodine staining for amylose had no detectable GBSS using sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) (wxa), and four were show to contain GBSS (wxb). Mean gelatinization onset, peak, and end temperatures were significantly lower for wild-type than either of the two waxy genotypes. Mean gelatinization onset temperature was slightly higher for waxy-GBSS+ genotypes than waxy-GBSS− genotypes. Mean gelatinization end temperature was slightly higher for waxy-GBSS− genotypes than waxy-GBSS+ genotypes. Significant genetic variation was observed within genotypic classes, suggesting influence of additional modifier genes affecting sorghum starch structure or micro-environmental effects

Occurrence of the Waxy Alleles \u3ci\u3ewxa\u3c/i\u3e and \u3ci\u3ewxb\u3c/i\u3e in Waxy Sorghum Plant Introductions and Their Effect on Starch Thermal Properties

The existence of two waxy alleles, wxa associated with no detectable granule bound starch synthase (GBSS) and wxb associated with apparently inactive GBSS, was recently reported in sorghum [Sorghum bicolor (L.) Moench]. In this paper, the occurrence of the wxa and wxb alleles in the USDA-ARS photoperiod-insensitive sorghum collection was determined, and the effects of the wxa and wxballeles on thermal properties of sorghum starch (gelatinization temperatures and energy requirements) measured by differential scanning calorimetry. Of the 51 purported waxy accessions examined, 14 tested positive for presence of amylose by iodine staining and were considered to be previously misclassified wild type lines. Nine accessions were mixed for presence or absence of amylose. Twenty-four of the 28 accessions confirmed to be waxy by negative iodine staining for amylose had no detectable GBSS using sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) (wxa), and four were show to contain GBSS (wxb). Mean gelatinization onset, peak, and end temperatures were significantly lower for wild-type than either of the two waxy genotypes. Mean gelatinization onset temperature was slightly higher for waxy-GBSS+ genotypes than waxy-GBSS− genotypes. Mean gelatinization end temperature was slightly higher for waxy-GBSS− genotypes than waxy-GBSS+ genotypes. Significant genetic variation was observed within genotypic classes, suggesting influence of additional modifier genes affecting sorghum starch structure or micro-environmental effects