1,330 research outputs found
Profits, Markups and Entry: Fiscal Policy in an Open Economy
In this paper we develop a general model of an imperfectly competitive small open economy. There is a traded and non-traded sector, whose outputs are combined in order to produce a single final good that can be either consumed or invested. We make general assumptions about preferences and technology, and analyze the impact of fiscal policy on the economy. We find that the fiscal multiplier is between zero and one, and provide sufficient conditions for it to be increasing in the degree of imperfect competition. We also are able to compare the multiplier under free-entry and with a fixed number of firms and welfare. A simple graphical representation of the model is developed.Imperfect competition, open economy, fiscal policy
Different strategies for recovering metals from CARON process residue
http://dx.doi.org/10.1016/j.jhazmat.2011.03.048The capacity of Acidithiobacillus thiooxidans DMS 11478 to recover the heavy metals contained in
the residue obtained from the CARON process has been evaluated. Different bioreactor configurations
were studied: a two-stage batch system and two semi-continuous systems (stirred-tank reactor
leaching and column leaching). In the two-stage system, 46.8% Co, 36.0% Mg, 26.3% Mn and 22.3% Ni
were solubilised after 6 h of contact between the residue and the bacteria-free bioacid. The results
obtained with the stirred-tank reactor and the column were similar: 50% of the Mg and Co and
40% of the Mn and Ni were solubilised after thirty one days. The operation in the column reactor
allowed the solid–liquid ratio to be increased and the pH to be kept at low values (<1.0). Recirculation
of the leachate in the column had a positive effect on metal removal; at sixty five days
(optimum time) the solubilisation levels were as follows: 86% Co, 83% Mg, 72% Mn and Ni, 62% Fe and
23% Cr. The results corroborate the feasibility of the systems studied for the leaching of metals from
CARON process residue and these methodologies can be considered viable for the recovery of valuable
metals
EDGE: a code to calculate diffusion of cosmic-ray electrons and their gamma-ray emission
The positron excess measured by PAMELA and AMS can only be explained if there
is one or several sources injecting them. Moreover, at the highest energies, it
requires the presence of nearby (hundreds of parsecs) and middle age
(maximum of hundreds of kyr) source. Pulsars, as factories of electrons
and positrons, are one of the proposed candidates to explain the origin of this
excess. To calculate the contribution of these sources to the electron and
positron flux at the Earth, we developed EDGE (Electron Diffusion and Gamma
rays to the Earth), a code to treat diffusion of electrons and compute their
diffusion from a central source with a flexible injection spectrum. We can
derive the source's gamma-ray spectrum, spatial extension, the all-electron
density in space and the electron and positron flux reaching the Earth. We
present in this contribution the fundamentals of the code and study how
different parameters affect the gamma-ray spectrum of a source and the electron
flux measured at the Earth.Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017),
Bexco, Busan, Kore
The calibration of the first Large-Sized Telescope of the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) represents the next generation of very
high-energy gamma-ray observatory, which will provide broad coverage of gamma
rays from 20 GeV to 300 TeV with unprecedented sensitivity. CTA will employ
three different sizes of telescopes, and the Large-Sized Telescopes (LSTs) of
23-m diameter dish will provide the sensitivity in the lowest energies down to
20 GeV. The first LST prototype has been inaugurated in October 2018 at La
Palma (Canary Islands, Spain) and has entered the commissioning phase. The
camera of the LST consists of 265 PMT modules. Each module is equipped with
seven high-quantum-efficiency Photomultiplier Tubes (PMTs), a slow control
board, and a readout board. Ensuring high uniformity and precise
characterization of the camera is the key aspects leading to the best
performance and low systematic uncertainty of the LST cameras. Therefore, prior
to the installation on site, we performed a quality check of all PMT modules.
Moreover, the absolute calibration of light throughput is essential to
reconstruct the amount of light received by the telescope. The amount of light
is affected by the atmosphere, by the telescope optical system and camera, and
can be calibrated using the ring-shaped images produced by cosmic-ray muons. In
this contribution, we will show the results of off-site quality control of PMT
modules and on-site calibration using muon rings. We will also highlight the
status of the development of Silicon Photomultiplier modules that could be
considered as a replacement of PMT modules for further improvement of the
camera
- …