836 research outputs found
Prediction of topographic changes of a circular sandy island using BG model
The BG model (a three-dimensional model for predicting beach changes based on Bagnold's concept) was applied to predict the three-dimensional topographic changes of a sandy island due to waves, which were observed in a movable-bed experiment by Uda and Yamamoto (1991). Taketomi island in the Sea of Okhotsk was formed as an island composed of sand by a volcanic eruption, the the island was markedly deformed by wave action, resulting in the formation of a double tombolo behind the island (Zenkovich, 1967). The BG model was also applied to predict these topographic changes of the island. The predicted and measured topographic changes in the two examples were in good agreement
Effects of anthropogenic factors on development of sand spits and cuspate forelands with rythmic shapes
The development of sand spits and cuspate forellands with rhythmic shapes was numerically predicted using the BG model (a 3-D model for predicting beach changes based on Bagnold's concept) under the oblique wave incidence that the angle between the direction normal to the shoreline and the wave direction is +-60 degrees, given an infinitesimal perturbation as the initial condition. Then the effects of the anthropogenic factors such as the construction of a groin and an offshore breakwater on the development of sand spits and cuspate forelands were investigated using the same model. The construction of a groin had a considerable impact on the sandy beach: the alteration from the field with the development of the sand spits to that with the elongation of a single sand spit, as well as the acceleration of offshore sand transport because of the blockage of longshore sand transport. The construction of an offshore breakwater strengthened the wave-seltering effect as well as the blockage of longshore sand transport, resulting in dominant beach changes. The calculated results in case of an offshore breakwater reasonably explained the example of the formation of the sand bars with two lagoons inside observed in a shallow lagoon surrounded by the Black Sea and Azov Sea
Change in carbonate beach triggered by construction of a bridge on Irabu island and its simulation using BG model
In constructing the Irabu bridge connecting Miyako to Irabu islands, a causeway was exended as part of the bridge on the reef flat, resulting in the formation of a wave-shelter zone on both sides of the causeway. After the construction, marked beach changes occured on the carbonate surrounded by a coral reef, and the nesting sites of the sea turtles were extensively lost. The BG model (a three-dimensional model for predicting beach changes based on Bagnold's concept) was applied to predict these beach changes. Then, the stabilization method of the beach was considered. A suitable measure was to install groins as well as beach nourishment
5-State Rotation-Symmetric Number-Conserving Cellular Automata are not Strongly Universal
We study two-dimensional rotation-symmetric number-conserving cellular
automata working on the von Neumann neighborhood (RNCA). It is known that such
automata with 4 states or less are trivial, so we investigate the possible
rules with 5 states. We give a full characterization of these automata and show
that they cannot be strongly Turing universal. However, we give example of
constructions that allow to embed some boolean circuit elements in a 5-states
RNCA
Analysis of mechanism of sand deposition inside a fishing port using BG model
A large amount of sand deposited in the wave-shelter zone of Ohtsu fishing port located in northern Ibaraki Prefecture, Japan, resulting in a difficulty in navigation at the pot entrance. The BG model (a three-dimensional model for predicting beach changes based on Bagnold's concept) ws used to solve this problem. Measures against sand deposition inside the port were investigated and the most appropriate measure found for preventing sand deposition was the extension of a jetty by 100 m at the tip of the west breakwater. The applicability of the BG model to such prediction was confirmed
Peritoneal and genital coccidioidomycosis in an otherwise healthy Danish female:a case report
BACKGROUND: Coccidioidomycosis is a fungal infection that usually presents as a primary lung infection. The fungus is endemic to the Southwest United States of America, northern Mexico and parts of Central and South America the infection is rare outside these areas. However, some patients develop disseminated infection that can lie dormant for several years and can present itself in travelers. We report the first case of extra pulmonary Coccidioidomycosis in a non-immunocompromised individual in Denmark. CASE PRESENTATION: A 32Â year old Danish woman presented at the Emergency department with abdominal pain. Computed tomography scan and ultrasound examination of the pelvis raised suspicion of salpingitis. A laparoscopy exposed a necrotic salpinx and several small white elements that resembled peritoneal carcinomatosis. Histological workup however determined that she suffered from disseminated coccidioidomycosis. The patient had lived 2Â years in Las Vegas, in the United States of America, 7Â years prior and had no memory of lung infection at the time. CONCLUSIONS: Disseminated coccidioidomycosis is rare in non-immunocompromised individuals. The patient in this case underwent several rounds of in vitro fertilization treatment in the years before admittance. We suspect that the hormonal treatment in combination with low-dose prednisolone may have triggered reemergence of the disease and present literature that support this
Topographic changes on Ajigura beach triggered by elongation of offshore breakwater
On Ajigaura Beach in Ibaraki Prefecture, Japan, severe beach erosion has occurred. Despite beach nourishment as a measure against beach erosion, wave run-up damage occurred in the south part of the beach where the foreshore was narrowed. The topographic changes of the beach were investigated on the basis of past aerial photographs and bathymetric survey data, and a numerical simulation using the BG model (a three-dimensional model for predicting beach changes based on Bagnold???s concept) was carried out. The measured and calculated results were in good agreement. It was concluded that the beach changes at Ajigaura Beach were triggered by northward longshore sand transport, which was induced by the wave-sheltering effect of the offshore breakwater
Di-neutron correlation and soft dipole excitation in medium mass neutron-rich nuclei near drip-line
The neutron pairing correlation and the soft dipole excitation in medium-mass
nuclei near drip-line are investigated from a viewpoint of the di-neutron
correlation. Numerical analyses by means of the coordinate-space HFB and the
continuum QRPA methods are performed for even-even O, Ca
and Ni. A clear signature of the di-neutron correlation is found in
the HFB ground state; two neutrons are correlated at short relative distances
\lesim 2 fm with large probability . The soft dipole excitation is
influenced strongly by the neutron pairing correlation, and it accompanies a
large transition density for pair motion of neutrons. This behavior originates
from a coherent superposition of two-quasiparticle configurations consisting of continuum states with high orbital angular momenta
reaching an order of . It raises a picture that the soft dipole
excitation under the influence of neutron pairing is characterized by motion of
di-neutron in the nuclear exterior against the remaining subsystem.
Sensitivity to the density dependence of effective pair force is discussed.Comment: 35 pages, 22 figure
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