5,433 research outputs found
The Dynamics of Economic Growth 1985-2000 in Chinese Provinces
This paper concerns the provincial growth pattern in China during the period 1985-2000. The hypothesis that provinces with similar growth rates are more spatially clustered than by pure chance is tested. In addition, we test the convergence hypothesis. We find evidence of spatial dependence between neighboring provinces and solve it by including a spatial lag, alternatively a spatial error term, in the growth equation. Other important factors explaining the provincial economic growth are foreign direct investments, infrastructure, preferential policies, and the distribution of industrial enterprises
Pattern Avoidance in k-ary Heaps
In this paper, we consider pattern avoidance in k-ary heaps, where the permutation associated with the heap is found by recording the nodes as they are encountered in a breadth-first search. We enumerate heaps that avoid patterns of length 3 and collections of patterns of length 3, first with binary heaps and then more generally with k-ary heaps
Upgraded demonstration vehicle task report
Vehicle/battery performance capabilities and interface problems that occurred when upgraded developmental batteries were integrated with upgraded versions of comercially available electric vehicles were investigated. Developmental batteries used included nickel zinc batteries, a nickel iron battery, and an improved lead acid battery. Testing of the electric vehicles and upgraded batteries was performed in the complete vehicle system environment to characterize performance and identify problems unique to the vehicle/battery system. Constant speed tests and driving schedule range tests were performed on a chassis dynamometer. The results from these tests of the upgraded batteries and vehicles were compared to performance capabilities for the same vehicles equipped with standard batteries
Controlling Access to Commercial Users by Telecommunications Providers—The FCC\u27s Failure to Separate the Market
Controlling Access to Commercial Users by Telecommunications Providers—The FCC\u27s Failure to Separate the Market
Universal Probability Distribution Function for Bursty Transport in Plasma Turbulence
Bursty transport phenomena associated with convective motion present
universal statistical characteristics among different physical systems. In this
letter, a stochastic univariate model and the associated probability
distribution function for the description of bursty transport in plasma
turbulence is presented. The proposed stochastic process recovers the universal
distribution of density fluctuations observed in plasma edge of several
magnetic confinement devices and the remarkable scaling between their skewness
and kurtosis . Similar statistical characteristics of variabilities have
been also observed in other physical systems that are characterized by
convection such as the X-ray fluctuations emitted by the Cygnus X-1 accretion
disc plasmas and the sea surface temperature fluctuations.Comment: 10 pages, 5 figure
The pumpistor: a linearized model of a flux-pumped SQUID for use as a negative-resistance parametric amplifier
We describe a circuit model for a flux-driven SQUID. This is useful for
developing insight into how these devices perform as active elements in
parametric amplifiers. The key concept is that frequency mixing in a
flux-pumped SQUID allows for the appearance of an effective negative
resistance. In the three-wave, degenerate case treated here, a negative
resistance appears only over a certain range of allowed input signal phase.
This model readily lends itself to testable predictions of more complicated
circuits.Comment: 4 pages, 3 figure
Neutral gas in Lyman-alpha emitting galaxies Haro 11 and ESO 338-IG04 measured through sodium absorption
Context. The Lyman alpha emission line of galaxies is an important tool for
finding galaxies at high redshift, and thus probe the structure of the early
universe. However, the resonance nature of the line and its sensitivity to dust
and neutral gas is still not fully understood.
Aims. We present measurements of the velocity, covering fraction and optical
depth of neutral gas in front of two well known local blue compact galaxies
that show Lyman alpha in emission: ESO 338-IG 04 and Haro 11. We thus test
observationally the hypothesis that Lyman alpha can escape through neutral gas
by being Doppler shifted out of resonance.
Methods. We present integral field spectroscopy from the GIRAFFE/Argus
spectrograph at VLT/FLAMES in Paranal, Chile. The excellent wavelength
resolution allows us to accurately measure the velocity of the ionized and
neutral gas through the H-alpha emission and Na D absorption, which traces the
ionized medium and cold interstellar gas, respectively. We also present
independent measurements with the VLT/X-shooter spectrograph which confirm our
results.
Results. For ESO 338-IG04, we measure no significant shift of neutral gas.
The best fit velocity is -15 (16) km/s. For Haro 11, we see an outflow from
knot B at 44 (13) km/s and infalling gas towards knot C with 32 (12) km/s.
Based on the relative strength of the Na D absorption lines, we estimate low
covering fractions of neutral gas (down to 10%) in all three cases.
Conclusions. The Na D absorption likely occurs in dense clumps with higher
column densities than where the bulk of the Ly-alpha scattering takes place.
Still, we find no strong correlation between outflowing neutral gas and a high
Lyman alpha escape fraction. The Lyman alpha photons from these two galaxies
are therefore likely escaping due to a low column density and/or covering
fraction.Comment: 9 pages, 3 figure
Right hemithoracic pseudocyst with splenic artery aneurysm: two rare complications of an uncommon disease
Pleural involvement is an uncommon but well recognized complication of chronic pancreatitis, mainly in the form of pleural effusion affecting the left hemithorax. Pancreatic pseudocyst extending to the posterior mediastinum with or without communication with the pleural space is another rare form of this involvement.The treatment of chronic pancreatic pleural effusions and pancreatic pseudocysts generally starts with a conservative approach including bowel rest, drainage of the pleural effusion by repeated thoracentesis or a chest tube, and total parenteral nutrition (TPN) for a period of time determined by the clinical course. Other treatment modalities including percutaneous drainage, endoscopic retrograde cholangiopancreatogram (ERCP) with stenting of the pancreatic duct and surgical drainage are used if conservative approaches fail.We report a patient with a complicated pancreatic pseudocyst who showed an involvement of the posterior mediastinum and right pleural space, with conspectus sparing of the left hemithorax. The patient had a prolonged and complicated course that included recurrence of the pseudocyst with oral feedings and the development of a splenic artery aneurysm. Some of the above findings have been reported separately as uncommon complications of chronic pancreatitis and pancreatic pseudcyst, but to our knowledge a single case with all these complications was not published in the English literature
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