72 research outputs found
First Test of Lorentz Invariance in the Weak Decay of Polarized Nuclei
A new test of Lorentz invariance in the weak interactions has been made by
searching for variations in the decay rate of spin-polarized 20Na nuclei. This
test is unique to Gamow-Teller transitions, as was shown in the framework of a
recently developed theory that assumes a Lorentz symmetry breaking background
field of tensor nature. The nuclear spins were polarized in the up and down
direction, putting a limit on the amplitude of sidereal variations of the form
|(\Gamma_{up} - \Gamma_{down})| / (\Gamma_{up} + \Gamma_{down}) < 3 * 10^{-3}.
This measurement shows a possible route toward a more detailed testing of
Lorentz symmetry in weak interactions.Comment: 11 pages, 6 figure
Diurnal variation and size dependence of the hygroscopicity of organic aerosol at a forest site in Wakayama, Japan: their relationship to CCN concentrations
Formation of biogenic secondary organic aerosol (BSOA)
and its subsequent evolution can modify the hygroscopicity of the organic
aerosol component (OA) in the forest atmosphere, and affect the
concentrations of cloud condensation nuclei (CCN) there. In this study,
size-resolved aerosol hygroscopic growth at 85 % relative humidity and
size-resolved aerosol composition were measured using a hygroscopic tandem
differential mobility analyzer and an aerosol mass spectrometer,
respectively, at a forest site in Wakayama, Japan, in August and September
2015. The hygroscopicity parameter of OA (κorg) presented daily
minima in the afternoon hours, and it also showed an increase with the increase in particle dry diameter. The magnitudes of the diurnal variations in
κorg for particles with dry diameters of 100 and 300 nm were on
average 0.091 and 0.096, respectively, and the difference in κorg between particles with dry diameters of 100 and 300 nm was on
average 0.056. The relative contributions of the estimated fresh BSOA and
regional OA to total OA could explain 40 % of the observed diurnal
variations and size dependence of κorg. The hygroscopicity
parameter of fresh BSOA was estimated to range from 0.089 to 0.12 for
particles with dry diameters from 100 to 300 nm. Compared with the use of
time- and size-resolved κorg, the use of time- and
size-averaged κorg leads to under- and over-estimation of the
fractional contribution of OA to CCN number concentrations in the range from
−5.0 % to 26 %. This indicates that the diurnal variations and
size dependence of κorg strongly affect the overall
contribution of OA to CCN concentrations. The fractional contribution of
fresh BSOA to CCN number concentrations could reach 0.28 during the period
of intensive BSOA formation. The aging of the fresh BSOA, if it occurs,
increases the estimated contribution of BSOA to CCN number concentrations by
52 %–84 %.</p
Universal Resistances of the Quantum RC circuit
We examine the concept of universal quantized resistance in the AC regime
through the fully coherent quantum RC circuit comprising a cavity (dot)
capacitively coupled to a gate and connected via a single spin-polarized
channel to a reservoir lead. As a result of quantum effects such as the Coulomb
interaction in the cavity and global phase coherence, we show that the charge
relaxation resistance is identical for weak and large transmissions and
it changes from to when the frequency (times ) exceeds
the level spacing of the cavity; is the Planck constant and the
electron charge. For large cavities, we formulate a correspondence between the
charge relaxation resistance and the Korringa-Shiba relation of the
Kondo model. Furthermore, we introduce a general class of models, for which the
charge relaxation resistance is universal. Our results emphasize that the
charge relaxation resistance is a key observable to understand the dynamics of
strongly correlated systems.Comment: 12 pages, 3 figure
Studies of an array of PbF2 Cherenkov crystals with large-area SiPM readout
The electromagnetic calorimeter for the new muon (g-2) experiment at Fermilab
will consist of arrays of PbF2 Cherenkov crystals read out by large-area
silicon photo-multiplier (SiPM) sensors. We report here on measurements and
simulations using 2.0 -- 4.5 GeV electrons with a 28-element prototype array.
All data were obtained using fast waveform digitizers to accurately capture
signal pulse shapes versus energy, impact position, angle, and crystal
wrapping. The SiPMs were gain matched using a laser-based calibration system,
which also provided a stabilization procedure that allowed gain correction to a
level of 1e-4 per hour. After accounting for longitudinal fluctuation losses,
those crystals wrapped in a white, diffusive wrapping exhibited an energy
resolution sigma/E of (3.4 +- 0.1) % per sqrt(E/GeV), while those wrapped in a
black, absorptive wrapping had (4.6 +- 0.3) % per sqrt(E/GeV). The
white-wrapped crystals---having nearly twice the total light
collection---display a generally wider and impact-position-dependent pulse
shape owing to the dynamics of the light propagation, in comparison to the
black-wrapped crystals, which have a narrower pulse shape that is insensitive
to impact position.Comment: 14 pages, 19 figures, accepted to Nucl.Instrum.Meth. A. In v2, edited
Figures 14,15, and 17 for clarity, improved explanation of energy resolution
systematics, added reference to SiP
Juvenile Hormone (JH) Esterase of the Mosquito Culex quinquefasciatus Is Not a Target of the JH Analog Insecticide Methoprene
Juvenile hormones (JHs) are essential sesquiterpenes that control insect development and reproduction. JH analog (JHA) insecticides such as methoprene are compounds that mimic the structure and/or biological activity of JH. In this study we obtained a full-length cDNA, cqjhe, from the southern house mosquito Culex quinquefasciatus that encodes CqJHE, an esterase that selectively metabolizes JH. Unlike other recombinant esterases that have been identified from dipteran insects, CqJHE hydrolyzed JH with specificity constant (kcat/KM ratio) and Vmax values that are common among JH esterases (JHEs). CqJHE showed picomolar sensitivity to OTFP, a JHE-selective inhibitor, but more than 1000-fold lower sensitivity to DFP, a general esterase inhibitor. To our surprise, CqJHE did not metabolize the isopropyl ester of methoprene even when 25 pmol of methoprene was incubated with an amount of CqJHE that was sufficient to hydrolyze 7,200 pmol of JH to JH acid under the same assay conditions. In competition assays in which both JH and methoprene were available to CqJHE, methoprene did not show any inhibitory effects on the JH hydrolysis rate even when methoprene was present in the assay at a 10-fold higher concentration relative to JH. Our findings indicated that JHE is not a molecular target of methoprene. Our findings also do not support the hypothesis that methoprene functions in part by inhibiting the action of JHE
The body unbound: ritual scarification and autobiographical forms in Wole Soyinka’s Aké: the years of childhood
The scarification in Aké is invested with major significance apropos Soyinka’s ideas on African
subjectivity. Scarification among the Yoruba is one of the rites of passage associated with personal
development. Scarification literally and metaphorically “opens” the person up socially and cosmically.
Personal formation and self-realization are enabled by the Yoruba social code brought into being
by its mythology. The meaning of the scarification incident in Aké is profoundly different. Determined
by the form of autobiography which creates a self-constituting subject, the enabling Yoruba sociocultural
context is elided. The story of Soyinka’s personal development is allegorical of the story
of the development of the modern African subject. For Soyinka, the African subject is a rational
subject whose constitution precludes the splitting of the scientific and spiritual which is a consequence
of the Cartesian rupture. The African subject should be open to other subjects and the object
world. Subjectivity constituted by the autobiographical mode closes off the opening up symbolically
signalled by scarification.Web of Scienc
Latent variables and route choice behavior
In the last decade, a broad array of disciplines has shown a general interest in enhancing discrete choice models by considering the incorporation of psychological factors affecting decision making. This paper provides insight into the comprehension of the determinants of route choice behavior by proposing and estimating a hybrid model that integrates latent variable and route choice models. Data contain information about latent variable indicators and chosen routes of travelers driving regularly from home to work in an urban network. Choice sets include alternative routes generated with a branch and bound algorithm. A hybrid model consists of measurement equations, which relate latent variables to measurement indicators and utilities to choice indicators, and structural equations, which link travelers' observable characteristics to latent variables and explanatory variables to utilities. Estimation results illustrate that considering latent variables (i.e., memory, habit, familiarity, spatial ability, time saving skills) alongside traditional variables (e.g., travel time, distance, congestion level) enriches the comprehension of route choice behavior
Muon (g-2) Technical Design Report
The Muon (g-2) Experiment, E989 at Fermilab, will measure the muon anomalous magnetic moment a factor-of-four more precisely than was done in E821 at the Brookhaven National Laboratory AGS. The E821 result appears to be greater than the Standard-Model prediction by more than three standard deviations. When combined with expected improvement in the Standard-Model hadronic contributions, E989 should be able to determine definitively whether or not the E821 result is evidence for physics beyond the Standard Model. After a review of the physics motivation and the basic technique, which will use the muon storage ring built at BNL and now relocated to Fermilab, the design of the new
experiment is presented. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2/3 approval
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