5,510 research outputs found
Gauge Equivalence in Two--Dimensional Gravity
Two-dimensional quantum gravity is identified as a second-class system which
we convert into a first-class system via the Batalin-Fradkin (BF) procedure.
Using the extended phase space method, we then formulate the theory in most
general class of gauges. The conformal gauge action suggested by David, Distler
and Kawai is derived from a first principle. We find a local, light-cone gauge
action whose Becchi-Rouet-Stora-Tyutin invariance implies Polyakov's curvature
equation , revealing the origin of the
Kac-Moody symmetry. The BF degree of freedom turns out be dynamically
active as the Liouville mode in the conformal gauge, while in the light-cone
gauge the conformal degree of freedom plays that r{\^o}le. The inclusion of the
cosmological constant term in both gauges and the harmonic gauge-fixing are
also considered.Comment: 30 pages, KANAZAWA 93-
High-fructose corn-syrup-sweetened beverage intake increases 5-hour breast milk fructose concentrations in lactating women
This study determined the effects of consuming a high-fructose corn syrup (HFCS)-sweetened beverage on breast milk fructose, glucose, and lactose concentrations in lactating women. At six weeks postpartum, lactating mothers (n = 41) were randomized to a crossover study to consume a commercially available HFCS-sweetened beverage or artificially sweetened control beverage. At each session, mothers pumped a complete breast milk expression every hour for six consecutive hours. The baseline fasting concentrations of breast milk fructose, glucose, and lactose were 5.0 ± 1.3 µg/mL, 0.6 ± 0.3 mg/mL, and 6.8 ± 1.6 g/dL, respectively. The changes over time in breast milk sugars were significant only for fructose (treatment × time, p < 0.01). Post hoc comparisons showed the HFCS-sweetened beverage vs. control beverage increased breast milk fructose at 120 min (8.8 ± 2.1 vs. 5.3 ± 1.9 µg/mL), 180 min (9.4 ± 1.9 vs. 5.2 ± 2.2 µg/mL), 240 min (7.8 ± 1.7 vs. 5.1 ± 1.9 µg/mL), and 300 min (6.9 ± 1.4 vs. 4.9 ± 1.9 µg/mL) (all p < 0.05). The mean incremental area under the curve for breast milk fructose was also different between treatments (14.7 ± 1.2 vs. −2.60 ± 1.2 µg/mL × 360 min, p < 0.01). There was no treatment × time interaction for breast milk glucose or lactose. Our data suggest that the consumption of an HFCS-sweetened beverage increased breast milk fructose concentrations, which remained elevated up to five hours post-consumption
Hybridization Mechanism for Cohesion of Cd-based Quasicrystals
Cohesion mechanism of cubic approximant crystals of newly discovered binary
quasicrystals, CdM (M=Yb and Ca), are studied theoretically. It is found
that stabilization due to alloying is obtained if M is an element with
low-lying unoccupied states. This leads to conclusion that the cohesion of
the Cd-based compounds is due to the hybridization of the states of Yb and
Ca with a wide band. %unlike known stable quasicrystals without transition
elements %such as Al-Li-Cu and Zn-Mg-RE (RE:rare earth). Although a diameter of
the Fermi sphere coincides with the strong Bragg peaks for Cd-Yb and Cd-Ca, the
Hume-Rothery mechanism does not play a principal role in the stability because
neither distinct pseudogap nor stabilization due to alloying is obtained for
isostructural Cd-Mg. In addition to the electronic origin, matching of the
atomic size is very crucial for the quasicrystal formation of the Cd-based
compounds. It is suggested that the glue atoms, which do not participate in the
icosahedral cluster, play an important role in stabilization of the compound.Comment: 4 pages, 2 figure
A Phase-Space Approach to Collisionless Stellar Systems Using a Particle Method
A particle method for reproducing the phase space of collisionless stellar
systems is described. The key idea originates in Liouville's theorem which
states that the distribution function (DF) at time t can be derived from
tracing necessary orbits back to t=0. To make this procedure feasible, a
self-consistent field (SCF) method for solving Poisson's equation is adopted to
compute the orbits of arbitrary stars. As an example, for the violent
relaxation of a uniform-density sphere, the phase-space evolution which the
current method generates is compared to that obtained with a phase-space method
for integrating the collisionless Boltzmann equation, on the assumption of
spherical symmetry. Then, excellent agreement is found between the two methods
if an optimal basis set for the SCF technique is chosen. Since this
reproduction method requires only the functional form of initial DFs but needs
no assumptions about symmetry of the system, the success in reproducing the
phase-space evolution implies that there would be no need of directly solving
the collisionless Boltzmann equation in order to access phase space even for
systems without any special symmetries. The effects of basis sets used in SCF
simulations on the reproduced phase space are also discussed.Comment: 16 pages w/4 embedded PS figures. Uses aaspp4.sty (AASLaTeX v4.0). To
be published in ApJ, Oct. 1, 1997. This preprint is also available at
http://www.sue.shiga-u.ac.jp/WWW/prof/hozumi/papers.htm
Induced Anisotropies in NiCo Obliquely Deposited Films and Their effect on Magnetic Domains
English Article: Oblique and in-plane anisotropies in obliquely evaporated NiCo thin films were investigated in order to understand their origin. All the compositions studied clearly show the effect of columnar grain morphology coupled with some intrinsic factors such as magnetostriction and crystallinity. Energy calculations are undertaken to explain the effect of
Nonlinear Supersymmetry, Brane-bulk Interactions and Super-Higgs without Gravity
We derive the coupling of a hypermultiplet of N=2 global supersymmetry to the
Dirac-Born-Infeld Maxwell theory with linear N=1 and a second nonlinear
supersymmetry. At the level of global supersymmetry, this construction
corresponds to the interaction with Maxwell brane fields of bulk
hypermultiplets, such as the universal dilaton of type IIB strings compactified
on a Calabi-Yau manifold. It displays in particular the active role of a
four-form field. Constrained N=1 and N=2 superfields and the formulation of the
hypermultiplet in its single-tensor version are used to derive the nonlinear
realization, allowing a fully off-shell description. Exact results with
explicit symmetries and supersymmetries are then obtained. The
electric-magnetic dual version of the theory is also derived and the gauge
structure of the interaction is exemplified with N=2 nonlinear QED of a charged
hypermultiplet. Its Higgs phase describes a novel super-Higgs mechanism without
gravity, where the goldstino is combined with half of the hypermultiplet into
an N=1 massive vector multiplet.Comment: 42 page
Magnetic properties of the Ag-In-rare-earth 1/1 approximants
We have performed magnetic susceptibility and neutron scattering measurements
on polycrystalline Ag-In-RE (RE: rare-earth) 1/1 approximants. In the magnetic
susceptibility measurements, for most of the RE elements, inverse
susceptibility shows linear behaviour in a wide temperature range, confirming
well localized isotropic moments for the RE ions. Exceptionally for the
light RE elements, such as Ce and Pr, non-linear behaviour was observed,
possibly due to significant crystalline field splitting or valence fluctuation.
For RE = Tb, the susceptibility measurement clearly shows a bifurcation of the
field-cooled and zero-field-cooled susceptibility at ~K,
suggesting a spin-glass-like freezing. On the other hand, neutron scattering
measurements detect significant development of short-range antiferromagnetic
spin correlations in elastic channel, which accompanied by a broad peak at
~meV in inelastic scattering spectrum. These features have
striking similarity to those in the Zn-Mg-Tb quasicrystals, suggesting that the
short-range spin freezing behaviour is due to local high symmetry clusters
commonly seen in both the systems.Comment: 14 pages, 12 figure
Timing of sea ice retreat can alter phytoplankton community structure in the western Arctic Ocean
This study assesses the response of phytoplankton assemblages to recent
climate change, especially with regard to the shrinking of sea ice in the
northern Chukchi Sea of the western Arctic Ocean. Distribution patterns of
phytoplankton groups in the late summers of 2008â2010 were analysed based
on HPLC pigment signatures and, the following four major algal groups were
inferred via multiple regression and cluster analyses: prasinophytes,
diatoms, haptophytes and dinoflagellates. A remarkable interannual
difference in the distribution pattern of the groups was found in the
northern basin area. Haptophytes dominated and dispersed widely in warm
surface waters in 2008, whereas prasinophytes dominated in cold water in
2009 and 2010. A difference in the onset date of sea ice retreat was evident
among yearsâthe sea ice retreat in 2008 was 1â2 months earlier than in
2009 and 2010. The spatial distribution of early sea ice retreat matched the
areas in which a shift in algal community composition was observed.
Steel-Dwass's multiple comparison tests were used to assess the physical,
chemical and biological parameters of the four clusters. We found a
statistically significant difference in temperature between the
haptophyte-dominated cluster and the other clusters, suggesting that the
change in the phytoplankton communities was related to the earlier sea ice
retreat in 2008 and the corollary increase in sea surface temperatures.
Longer periods of open water during the summer, which are expected in the
future, may affect food webs and biogeochemical cycles in the western Arctic
due to shifts in phytoplankton community structure
The effect of 1.0% tropicamide/2.5% phenylephrine and Paremyd on pupil diameter, accomodative amplitude and intraocular pressure
Background: The demand for a milder, yet effective dilation drop prompted Allergan to introduce Paremyd⢠to the eye care community in 1993. This study sought to form clinical comparisons between Paremyd⢠and the standard drug regimen for dilation of 1% tropicamide/2.5% phenylephrine.
Methods: 23 subjects who ranged from 23-29 years of age were dilated with 1 drop each of 1% tropicamide and 2.5% phenylephrine in the right eye and 1 drop of Paremyd⢠in the left eye. Pupil diameter and accommodative amplitude (using the push up method) was evaluated at 0, 10, 20, 30, 45, 60, 90, 120, 150 and 180 minute intervals while intraocular pressures were attained at 0, 30, 60, 120 and 180 minute intervals.
Results: Analysis revealed that Paremyd⢠had a slightly less mydriatic and cycloplegic effect than the standard drug regimen. There was also a difference in efficacy when segregating participants due to irides\u27 color with both dilation methods having a greater mydriatic effect on non-brown eyed vs. brown eyed subjects. The reverse was true when cycloplegic effect was analyzed.
Conclusions: It is difficult to assess which regimen should be the drug or drugs of choice with regard to pupil dilation. Paremyd⢠proves to be an effective, milder mydriatic agent. Although in brown eyed individuals, one drop of Paremyd⢠may fall slightly short of the desired 7 mm dilated pupil
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