117,415 research outputs found
Optimal Monetary and Fiscal Policies In a Search-theoretic Model of Money and Unemployment
No full textIn this paper we study the optimal monetary and fiscal policies of a general equilibrium model of unemployment and money with search frictions both in labor and goods markets as in Berentsen, Menzio and Wright (2010). We abstract from revenue-raising motives to focus on the welfare-enhancing properties of optimal policies. We show that some of the inefficiencies in the Berentsen, Menzio and Wright (2010) framework can be restored with appropriate fiscal policies. In particular, when lump sum monetary transfers are possible, a production subsidy financed by money printing can increase output in the decentralized market and a vacancy subsidy financed by a dividend tax even when the Hosios’ rule does not hold.Search and matching, Fiscal polices,Money, Unemployment, Efficiency
SICURA: a new handheld radionuclide identification device with gamma and neutron response
No full textSICURA is a two-year project that aims to develop a portable device to be employed in the prevention of illicit trafficking of radioactive material through γ and neutron detection. In order to be attractive to industries, efforts were made to fulfill the following characteristics: portability, good photon energy resolution and sensitivity in compliance with relevant international standards, sensitivity to neutrons with energies typical of the most common sources, fast response, low cost, user friendly interface. The SICURA system consists of two photon detectors for photon detection (CsI) and spectrometry (CZT) and a moderated Helium-3 counter for neutron detection. Dedicated analog and digital electronics readout have been developed, ensuring high energy resolution for accurate elements identification, signal digitization, alarm and information transmission to the end user. This paper describes the development of the SICURA device and the first results of its individual detectors characterizations
Optimal Monetary and Fiscal Policies in a Search-Theoretic Model of Money and Unemployment
No full textIn this paper we study the optimal monetary and fiscal policies of a general equilibrium model of unemployment and money with search frictions both in labor and goods markets as in Berentsen, Menzio and Wright (2010). We abstract from revenue-raising motives to focus on the welfare-enhancing properties of optimal policies. We show that some of the inefficiencies in the Berentsen, Menzio and Wright (2010) framework can be restored with appropriate fiscal policies. In particular, when lump sum monetary transfers are possible, a production subsidy financed by money printing can increase output in the decentralized market and a vacancy subsidy financed by a dividend tax even when the Hosios’ rule does not hold.Search and matching; Fiscal polices; Money; Unemployment; Efficiency
Design of a novel compact neutron collimator
No full textIn this work the concept of a novel slow neutron collimator and the way to operate it are presented. The idea is based on the possibility to decouple the device's field-of-view from its collimation power. A multi-channel geometry is proposed consisting of a chess-board structure where highly neutron-absorbing channels are alternated to air channels. A borated polymer was purposely developed to produce the attenuating components in the form of square-sectioned long rods. A scalable structure consisting of multiple collimation sectors can be arranged. The geometrical parameter L/D, corresponding to the ratio between the length of a channel and its width, defines the collimation power. Several sectors can be arranged one after the other to reach relevant collimation powers. Each sector, 100 mm long, is composed by several channels with D = 2.5 mm corresponding to an L/D coefficient of 40. The target field of view is 50×50 mm2. This novel collimator, developed inside the INFN-ANET collaboration, due to its intrinsic compactness, will be of great importance to enhance the neutron imaging capability of small to medium-size neutron sources
Block Recursive Equilibria for Stochastic Models of Search on the Job
No full textIn this paper, we develop a general stochastic model of directed search on the job. Like in the analogous models of random search on the job, the state of the economy in our model includes the infinite-dimensional distribution of workers across different employment states (unemployment, and employment at different wages). Unlike the analogous models of random search on the job, our model admits an equilibrium in which the agents' value and policy functions do not depend on the distribution of workers. We refer to this type of equilibrium as a Block Recursive Equilibrium. Therefore, while solving the equilibrium of a random search model in a stochastic environment is a difficult task both analytically and computationally, solving the Block Recursive Equilibrium of our model is as easy as solving a representative agent model.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A numerical model to predict pulse height distribution of alpha particles in thin ZnS(Ag) scintillators
No full textThe SnowWhite7 numerical model was developed to predict pulse height distribution from multicrystalline ZnS(Ag) scintillators exposed to alpha particles. The model, implemented in LabView, treats the following effects: charged particle energy loss, stopping-power-dependent light yield, and light self absorption in the multicrystalline matrix. SnowWhite7 was validated against experimental data obtained with scintillators manufactured at INFN-LNF and having thickness from 1.6 mg
cm
up to about 10 mg
cm−2. The scintillation light output was collected using a commercial photomultiplier and a digitizer. SnowWhite7 internal parameters were adjusted to satisfactorily match the experimental spectra. SnowWhite7 will be used in a broader project on the design of neutron sensitive scintillators based on ZnS(Ag) combined with 6LiF
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
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