Distribution of radioactive jackrabbit pellets in the vicinity of the B-C CRIBS, 200 East Area, U.S.A.E.C. Hanford Reservation

During 1972 and 1973 a study was conducted in the B-C Cribs, 200 East Area, to learn the extent to which jackrabbits (Lepus californicus) and their predators had dispersed buried radioactive wastes in their fecal pellets and scats. The specific objective was to gather sufficient data on the pattern of dispersal so that statistically valid sampling strategies could be developed in future programs, depending upon management planning objectives for the area. A secondary objective was to relate these data with parameters, such as topography, wind direction, vegetation types, animal behavior, that might help explain the pattern of dispersal. In 1972, 2625 circular sampling sites were surveyed along 30 transects radiating out 2.4 to 3.2 km from the B-C Cribs. Radioactive contaminated feces, urine, soil and vegetation were distributed in all directions from the cribs, but the area to the south and southwest was more densely and uniformly contaminated. Of the ultimate sampling units surveyed, 278 or 10.6% had activity in excess o f 10,000 counts per minute (cprn) measured with a Geiger-Mueller counter. Of these 278 circular areas, 179 or 64% were found within 0.5 km of the cribs, 23.4% were between 0.5 and 1.0 km, and the remaining 12.2% were further than 1 km from the central point. Although most droppings with a count rate greater than 20,000 cpm were found within 400 meters of the crib, pellets registering in excess of 100,000 cprn were found up to 1.6 km from the cribs. The pellets appeared to be distributed into the prevailing wind directions and contrary to the immediate contours: the only correlation seemed to be with increased vegetation density to the south and southwest, vegetation that is prime jackrabbit habitat. In May-June, 1973, 48 additional transects were run: 7 were parallel to lines established in the B-C Crib Area during 1972; 18 radiated from an abandoned gun battery site 3.2 km east of the cribs; and 23 were run from power lines 5 km south to southwest of the cribs back towards the source of contamination. No contaminated jackrabbit pellets were found at these distances, but one contaminated coyote scat was found near the gun battery site. During 1972 and 1973 field crews walked 106.7 km along 78 radii and recorded observations on 6671 ultimate sampling units of approximately 1.4 m{sup 2}

Hybridization of sub-gap states in one-dimensional superconductor/semiconductor Coulomb islands

We present measurements of one-dimensional superconductor-semiconductor Coulomb islands, fabricated by gate confinement of a two-dimensional InAs heterostructure with an epitaxial Al layer. When tuned via electrostatic side gates to regimes without sub-gap states, Coulomb blockade reveals Cooper-pair mediated transport. When sub-gap states are present, Coulomb peak positions and heights oscillate in a correlated way with magnetic field and gate voltage, as predicted theoretically, with (anti) crossings in (parallel) transverse magnetic field indicating Rashba-type spin-orbit coupling. Overall results are consistent with a picture of overlapping Majorana zero modes in finite wires

Tunable, Concurrent Multiband, Single Chain Radio Architecture for Low Energy 5G-RANs

This invited paper considers a key next step in the design of radio architectures aimed at supporting low energy consumption in 5G heterogeneous radio access networks. State-of-the-art mobile radios usually require one RF transceiver per standard, each working separately at any given time. Software defined radios, while spanning a wide range of standards and frequency bands, also work separately at any specific time. In 5G radio access networks, where continuous, multiband connectivity is envisaged, this conventional radio architecture results in high network power consumption. In this paper, we propose the novel concept of a concurrent multiband frequency-agile radio (CM-FARAD) architecture, which simultaneously supports multiple standards and frequency bands using a single, tunable transceiver. We discuss the subsystem radio design approaches for enabling the CM-FARAD architecture, including antennas, power amplifiers, low noise amplifiers and analogue to digital converters. A working prototype of a dual-band CM-FARAD test-bed is also presented together with measured salient performance characteristics

Supercurrent transport through 1ee-periodic full-shell Coulomb islands

We experimentally investigate supercurrent through Coulomb islands, where island and leads are fabricated from semiconducting nanowires with fully surrounding superconducting shells. Applying flux along the wire yields a series of destructive Little-Parks lobes with reentrant supercurrent. We find Coulomb blockade with 2$e$ peak spacing in the zeroth lobe and 1$e$ average spacing, with regions of significant even-odd modulation, in the first lobe. Evolution of Coulomb-peak amplitude through the first lobe is consistent with a theoretical model of supercurrent carried predominantly by zero-energy states in the leads and the island.Comment: 11 pages, 5+5 figure

Evidence for Dirac nodes from quantum oscillations in SrFe2As2

We present a detailed study of quantum oscillations in the antiferromagnetically ordered pnictide compound SrFe2As2 as the angle between the applied magnetic field and crystalline axes is varied. Our measurements were performed on high-quality single crystals in a superconducting magnet, and in pulsed magnetic fields up to 60 T, allowing us to observe orbits from several small Fermi-surface pockets. We extract the cyclotron effective mass m☆ and frequency F for these orbits and track their values as the field is rotated away from the c axis. While a constant ratio of m☆/F is expected for a parabolic band, we observe deviations from this behavior. We conclude that this observation points to orbits derived from a band with Dirac dispersion near the Fermi level

Quiescence: early evolutionary origins and universality do not imply uniformity

Cell cycle investigations have focused on relentless exponential proliferation of cells, an unsustainable situation in nature. Proliferation of cells, whether microbial or metazoan, is interrupted by periods of quiescence. The vast majority of cells in an adult metazoan lie quiescent. As disruptions in this quiescence are at the foundation of cancer, it will be important for the field to turn its attention to the mechanisms regulating quiescence. While often presented as a single topic, there are multiple forms of quiescence each with complex inputs, some of which are tied to conceptually challenging aspects of metazoan regulation such as size control. In an effort to expose the enormity of the challenge, I describe the differing biological purposes of quiescence, and the coupling of quiescence in metazoans to growth and to the structuring of tissues during development. I emphasize studies in the organism rather than in tissue culture, because these expose the diversity of regulation. While quiescence is likely to be a primitive biological process, it appears that in adapting quiescence to its many distinct biological settings, evolution has diversified it. Consideration of quiescence in different models gives us an overview of this diversity