1,635 research outputs found
Crustal structure between the Knipovich Ridge and the Van Mijenfjorden (Svalbard)
The Alfred Wegener Institute of Polar and Marine Research, the University of Bergenand the Hokkaido University acquired new seismic refraction data along a transect fromthe Knipovich Ridge to the inner Van Mijenfjorden in southern Svalbard. A close spacing ofon- and offshore receivers and a dense marine shot pattern provide the data for a high resolutionp-wave velocity model for geological interpretation. Additional new seismic reflection data(University of Bergen) yield structural information for a more reliable analysis.Crustal thickness along the Van Mijenfjorden is 33 to 34 km. Seismic velocities of 5.0 km/sare observed within the upper crustal section of the Tertiary Central Spitsbergen Basin.A Paleozoic sedimentary basin with a depth of 8 to 10 km is associated with the Nordfjorden Block.The seismic velocities are up to 6.0 km/s. Paleozoic sedimentary rocks are expected furtherto the west of the Hornsund Lineament since seismic velocities reveal a similar range here.West of the Bellsund the continental crust thins gradually over a 90 km wide rifted zone.The velocity structure within this section is very complex and comprises zones of decreasedvelocities below the West Spitsbergen Fold Belt (down to 20 km depth) and slightly elevatedvelocities (7.2 km/s) at the crust-mantle transition. The first structure is interpreted as intensivelyfractured rocks linked to post-Late Paleocene transpressive orogenic activity and subsequentlyaffected by transtension during break-up from Greenland. The faster deep-crustal velocities aresupposed to express magmatic intrusions of an unidentified origin. Melts could either be channelled by theSpitsbergen Shear Zone from more distant sources, or originate in magmatic interaction between the northern Knipovich Ridgeand the neighbouring young rifted crust.Oceanic crust each side of the Knipovich Ridge is thin (~3.5 km) and is characterised by theabsence of oceanic layer 3 (3.5/4.1 to 4.7 km/s). The oceanic section exhibits zones of verythin crust (~1 km) that are interpreted as fracture zones. Beneath these we observed decreasedmantle velocities (~7.3 km/s) indicating probable serpentinization of peridotites along thesefracture zones. Thickness variations further provide information about the segmentationand magma supply along the northern Knipovich Ridge
Scattering functions of knotted ring polymers
We discuss the scattering function of a Gaussian random polygon with N nodes
under a given topological constraint through simulation. We obtain the Kratky
plot of a Gaussian polygon of N=200 having a fixed knot for some different
knots such as the trivial, trefoil and figure-eight knots. We find that some
characteristic properties of the different Kratky plots are consistent with the
distinct values of the mean square radius of gyration for Gaussian polygons
with the different knots.Comment: 4pages, 3figures, 3table
Experimental ancilla-assisted qubit transmission against correlated noise using quantum parity checking
We report the experimental demonstration of a transmission scheme of photonic
qubits over unstabilized optical fibers, which has the plug-and-play feature as
well as the ability to transmit any state of a qubit, regardless of whether it
is known, unknown, or entangled to other systems. A high fidelity to the
noiseless quantum channel was achieved by adding an ancilla photon after the
signal photon within the correlation time of the fiber noise and by performing
quantum parity checking. Simplicity, maintenance-free feature and robustness
against path-length mismatches among the nodes make our scheme suitable for
multi-user quantum communication networks.Comment: 8 pages, 4 figures; published in New J. Phys. and selected in IOP
Selec
Attenuation of ischemic liver injury by monoclonal anti-endothelin antibody, awETN40
Background: Enhanced production of endothelin-1 (ET1), vasoconstrictive 21 amino acids produced by endothelial cells during ischemia and after reperfusion of the liver, is known to cause sinusoidal constriction and microcirculatory disturbances, which lead to severe tissue damage. Using a 2- hour hepatic vascular exclusion model in dogs, we tested our hypothesis that neutralization of ET-1 by monoclonal anti-ET-1 and anti-ET-2 antibody (AwETN40) abates vascular dysfunction and ameliorates ischemia/reperfusion injury of the liver. Study Design: After skeletonization, the liver was made totally ischemic by cross-clamping the portal vein, the hepatic artery, and the vena cava (above and below the liver). Venovenous bypass was used to decompress splanchnic and inferior systemic congestion. AwETN40, 5 mg/kg, was administered intravenously 10 minutes before ischemia (treatment group, n = 5). Nontreated animals were used as controls (control group, n = 10). Animal survival, hepatic tissue blood flow, liver function tests; total bile acid, high-energy phosphate, ET-1 levels, and liver histopathology were studied. Results: Treatment with AwETN40 improved 2-week animal survival from 30% to 100%. Hepatic tissue blood flow after reperfusion was significantly higher in the treatment group. The treatment significantly attenuated liver enzyme release, total bile acid, and changes in adenine nucleotides. Immunoreactive ET-1 levels in the hepatic venous blood of the control group showed a significant increase and remained high for up to 24 hours after reperfusion. Histopathologic alterations were significantly lessened in the treatment group. Conclusions: These results indicate that ET-1 is involved in ischemia/reperfusion injury of the liver, which can be ameliorated by the monoclonal anti-ET-1 and antiET-2 antibody AwETN40
Search for long-lived states in antiprotonic lithium
The spectrum of the (L_i^3 + p-bar + 2e) four-body system was calculated in
an adiabatic approach. The two-electron energies were approximated by a sum of
two single-electron effective charge two-center energies as suggested in [6].
While the structure of the spectrum does not exclude the existence of
long-lived states, their experimental observability is still to be clarified
Relaxation of a Single Knotted Ring Polymer
The relaxation of a single knotted ring polymer is studied by Brownian
dynamics simulations. The relaxation rate lambda_q for the wave number q is
estimated by the least square fit of the equilibrium time-displaced correlation
function to a double exponential decay at long times. The relaxation rate
distribution of a single ring polymer with the trefoil knot appears to behave
as lambda_q=A(1/N^)x for q=1 and lambda_q=A'(q/N)^x' for q=2 and 3, where
x=2.61, x'=2.02 and A>A'. The wave number q of the slowest relaxation rate for
each N is given by q=2 for small values of N, while it is given by q=1 for
large values of N. This crossover corresponds to the change of the structure of
the ring polymer caused by the localization of the knotted part to a part of
the ring polymer.Comment: 13 pages, 5 figures, uses jpsj2.cl
Comparison between Serum and Saliva Biochemical Constituents in Dairy Cows during Lactation and Dry Period
The present study was undertaken to compare serum and salivary biochemical constituents during lactation and dry period in dairy cows. Also, the present study evaluated for the first time the salivary biochemical constituents in dairy cows. The study was carried out using 45 healthy multiparous Holstein cows maintained in dairy farms located in Morioka city (Iwate prefecture, Japan). Cows were classified into groups based on the month of lactation. Serum, saliva and milk samples were collected and analyzed. Data were statistically analyzed and the variation in serum and salivary biochemical constituents during lactation and dry period were discussed. From the present study, it could be concluded that the 1st month of lactation has the highest levels for serum free fatty acids (FFA), β- Hydroxy butyric acid (BHBA) and aceto Acetic acid (ACAC). The dry period has the highest serum glucose level and the lowest serum FFA, BHBA and aspartate aminotransferase levels. Both serum and salivary FFA showed the highest value during the 1st month of lactation. Saliva contains a high level of gamma glutamyl transferase. The level of ammonia in saliva is higher than its serum level during all months of lactation and dry period. Most of the biochemical constituents in saliva change in different way from serum during lactation and dry period. Milk protein/fat ratio of 0.7 may be not indicative for subclinical ketosis
One-way quantum computing in a decoherence-free subspace
We introduce a novel scheme for one-way quantum computing (QC) based on the
use of information encoded qubits in an effective cluster state resource. With
the correct encoding structure, we show that it is possible to protect the
entangled resource from phase damping decoherence, where the effective cluster
state can be described as residing in a Decoherence-Free Subspace (DFS) of its
supporting quantum system. One-way QC then requires either single or two-qubit
adaptive measurements. As an example where this proposal can be realized, we
describe an optical lattice setup where the scheme provides robust quantum
information processing. We also outline how one can adapt the model to provide
protection from other types of decoherence.Comment: 9 pages, 4 figures, RevTeX
Average Structures of a Single Knotted Ring Polymer
Two types of average structures of a single knotted ring polymer are studied
by Brownian dynamics simulations. For a ring polymer with N segments, its
structure is represented by a 3N -dimensional conformation vector consisting of
the Cartesian coordinates of the segment positions relative to the center of
mass of the ring polymer. The average structure is given by the average
conformation vector, which is self-consistently defined as the average of the
conformation vectors obtained from a simulation each of which is rotated to
minimize its distance from the average conformation vector. From each
conformation vector sampled in a simulation, 2N conformation vectors are
generated by changing the numbering of the segments. Among the 2N conformation
vectors, the one closest to the average conformation vector is used for one
type of the average structure. The other type of the averages structure uses
all the conformation vectors generated from those sampled in a simulation. In
thecase of the former average structure, the knotted part of the average
structure is delocalized for small N and becomes localized as N is increased.
In the case of the latter average structure, the average structure changes from
a double loop structure for small N to a single loop structure for large N,
which indicates the localization-delocalization transition of the knotted part.Comment: 15 pages, 19 figures, uses jpsj2.cl
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