6,971 research outputs found
Ecology and Economic Impact of the Invasive Brown Marmorated Stink Bug (Hemiptera: Pentatomidae; Halyomorpha halys) in the Utah Agricultural Landscape
The brown marmorated stink bug (BMSB) is a major insect pest that causes economic loss to a diversity of U.S. fruit and vegetable crops, and invades homes and human structures, causing nuisance issues for homeowners. This destructive insect causes millions of dollars of crop damage annually, and is difficult to manage due to its resistance to some common insecticides. BMSB is a relatively new pest to Utah, and its biology and ecology is not well known in the high elevation, arid Intermountain West region. In Chapter II, I explored the potential impact of BMSB to tart cherry, an unstudied crop in regards to BMSB susceptibility. I determined that tart cherry fruits may abort if fed on by BMSB from the flower petal-fall through fruit pit-hardening stages, causing severe economic loss. In Chapter III, I evaluated several commercially available stink bug traps baited with pheromone lures in diverse specialty crop habitats to assess BMSB location preferences and attraction to traps. These results will guide BMSB monitoring and management decision-making. I found that Utah specialty crop fields are often small enough in size that BMSB invades the entire site and does not concentrate around field borders as in other U.S. regions. Additionally, I determined that pyramid-style traps were more effective in attracting BMSB under low densities as experienced in Utah to-date. Lastly, in Chapters IV and V, I discuss findings and results of surveys for parasitoid wasps that attack and kill developing BMSB eggs, and share extension materials aimed to inform growers and the public about biological control agents of this pest in the Utah agricultural landscape
Adiabatic radio frequency potentials for the coherent manipulation of matter waves
Adiabatic dressed state potentials are created when magnetic sub-states of
trapped atoms are coupled by a radio frequency field. We discuss their
theoretical foundations and point out fundamental advantages over potentials
purely based on static fields. The enhanced flexibility enables one to
implement numerous novel configurations, including double wells, Mach-Zehnder
and Sagnac interferometers which even allows for internal state-dependent atom
manipulation. These can be realized using simple and highly integrated wire
geometries on atom chips.Comment: 13 pages, 2 figure
Ultracold atoms in radio-frequency-dressed potentials beyond the rotating wave approximation
We study dressed Bose-Einstein condensates in an atom chip radio-frequency
trap. We show that in this system sufficiently strong dressing can be achieved
to cause the widely used rotating wave approximation (RWA) to break down. We
present a full calculation of the atom - field coupling which shows that the
non-RWA contributions quantitatively alter the shape of the emerging dressed
adiabatic potentials. The non-RWA contributions furthermore lead to additional
allowed transitions between dressed levels. We use RF spectroscopy of
Bose-Einstein condensates trapped in the dressed state potentials to directly
observe the transition from the RWA to the beyond-RWA regime.Comment: 6 pages, 4 figure
Noise Thermometry with Two Weakly Coupled Bose-Einstein Condensates
Here we report on the experimental investigation of thermally induced
fluctuations of the relative phase between two Bose-Einstein condensates which
are coupled via tunneling. The experimental control over the coupling strength
and the temperature of the thermal background allows for the quantitative
analysis of the phase fluctuations. Furthermore, we demonstrate the application
of these measurements for thermometry in a regime where standard methods fail.
With this we confirm that the heat capacity of an ideal Bose gas deviates from
that of a classical gas as predicted by the third law of thermodynamics.Comment: 4 pages, 4 figure
Modeling meander morphodynamics over self-formed heterogeneous floodplains
This work addresses the signatures embedded in the planform geometry of meandering rivers consequent to the formation of floodplain heterogeneities as the river bends migrate. Two geomorphic features are specifically considered: scroll bars produced by lateral accretion of point bars at convex banks and oxbow lake fills consequent to neck cutoffs. The sedimentary architecture of these geomorphic units depends on the type and amount of sediment, and controls bank erodibility as the river impinges on them, favoring or contrasting the river migration. The geometry of numerically generated planforms obtained for different scenarios of floodplain heterogeneity is compared to that of natural meandering paths. Half meander metrics and spatial distribution of channel curvatures are used to disclose the complexity embedded in meandering geometry. Fourier Analysis, Principal Component Analysis, Singular Spectrum Analysis and Multivariate Singular Spectrum Analysis are used to emphasize the subtle but crucial differences which may emerge between apparently similar configurations. A closer similarity between observed and simulated planforms is attained when fully coupling flow and sediment dynamics (fully-coupled models) and when considering self-formed heterogeneities that are less erodible than the surrounding floodplain
Two-point density correlations of quasicondensates in free expansion
We measure the two-point density correlation function of freely expanding
quasicondensates in the weakly interacting quasi-one-dimensional (1D) regime.
While initially suppressed in the trap, density fluctuations emerge gradually
during expansion as a result of initial phase fluctuations present in the
trapped quasicondensate. Asymptotically, they are governed by the thermal
coherence length of the system. Our measurements take place in an intermediate
regime where density correlations are related to near-field diffraction effects
and anomalous correlations play an important role. Comparison with a recent
theoretical approach described by Imambekov et al. yields good agreement with
our experimental results and shows that density correlations can be used for
thermometry of quasicondensates.Comment: 4 pages, 4 figures, minor change
Hadron multiplicities in e+e- annihilation with heavy primary quarks
The multiple hadron production in the events induced by the heavy primary
quarks in annihilation is reconsidered with account of corrected
experimental data. New value for the multiplicity in events is
presented on the basis of pQCD estimates.Comment: 16 pages, 6 figures. Version accepted for publication in EPJ
Effect of Magnetization Inhomogeneity on Magnetic Microtraps for Atoms
We report on the origin of fragmentation of ultracold atoms observed on a
permanent magnetic film atom chip. A novel technique is used to characterize
small spatial variations of the magnetic field near the film surface using
radio frequency spectroscopy of the trapped atoms. Direct observations indicate
the fragmentation is due to a corrugation of the magnetic potential caused by
long range inhomogeneity in the film magnetization. A model which takes into
account two-dimensional variations of the film magnetization is consistent with
the observations.Comment: 4 pages, 4 figure
Common Stink Bugs of Utah
This fact sheet provides information of some of Utah\u27s commonly encountered stink bugs, including what they look like, where to find them, and other key identifying characteristics
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