Can market-clearing models explain U.S. labor market fluctuations?

Throughout the past two decades, market-clearing models of the business cycle have been praised for their ability to explain key empirical features of the post-war U.S. business cycle. Real business cycle (RBC) theory shows that in a model grounded in microeconomic foundations, disturbances to national productivity can explain how aggregate variables such as GDP, consumption and investment behave over time, relative to each other. One of the primary weaknesses of the standard RBC model, however, is its inability to account for some important aspects of U.S. labor market fluctuations. In this article, Victor E. Li summarizes important U.S. business cycle facts and examines how and why these market-clearing models have so much difficulty explaining the mannner in which these facts pertain to the labor market. Li then develops a simple market-clearing framework that demonstrates how a more realistic treatment of unemployment and incomplete risk-sharing may provide an alternative approach to better account for these labor market facts. In particular, Li looks at the situation where the risk of being unemployed cannot be completely shared across all individuals when there are unexpected aggregate economic shocks.Business cycles ; Labor market ; Econometric models

Decentralized Exchange and Factor Payments: A Multiple-Matching Approach

The emergence of fiat money is studied in an environment in which exchange is organized around trading posts where many producers and shoppers are matched in a dynamic monopolistically competitive framework. Each household consumes a bundle of commodities and has a preference for consumption variety. Within this multiple matching structure we determine the endogenous organization of exchange between firms and shoppers and the means of factor payment (remuneration) as well as the price at which these trades occur. Although each household contacts many sellers, the specialization of tastes implies that the variety of the consumption basket under barter mediated exchange is sparser than that obtained under monetary exchange. We verify that the endogenous linkage of factor payments with the medium of exchange can lead to a monetary equilibrium outcome where only fiat money trades for goods, an ex-ante feature of cash-in-advance models. We also examine the long-run effects of money growth on the equilibrium pattern of exchange. A primary finding, consistent with documented hyperinflationary episodes, is that a sufficiently rapid expansion of money supply and inflation leads to the gradual emergence of barter. Under these circumstances sellers will accept both goods and cash payments whereas workers receive part of their remuneration in goods.Variety Preference, Search, Trading Post, Monetary vs. Barter Equilibrium

Credit Mismatch and Breakdown

This paper studies the phenomenon of mismatch in a decentralized credit market where borrowers and lenders must engage in costly search to establish credit relationships. Our dynamic general equilibrium framework integrates incentive based informational frictions with a matching process highlighted by (i) borrowers’ endogenous market entry and exit decision (entry frictions) and (ii) time and resource costs necessary to locate credit opportunities (search frictions). A key feature of the incentive compatible loan contract negotiated between borrowers and lenders is the interaction of informational frictions (in the form of moral hazard) with entry and search frictions. We find that the removal of entry barriers can eliminate information-based equilibrium credit rationing. More generally, entry and incentive frictions are important in understanding the extent of credit rationing, while entry and search frictions are important for understanding credit market breakdown.Entry, Moral Hazard, Credit Rationing, Credit Mismatch, Credit-Market Breakdown

Inflation and economic activity in a multiple matching model of money

This paper investigates the relationship between money growth, inflation, and productive activity in a general equilibrium model where search frictions motivate the transactions role of money. The use of a multiple matching technique, where search frictions are captured by limited consumption variety, allows us to study price determination in a search-theoretic environment with divisible money and goods. We find that in such a setting, a positive feedback between work and shopping effort decisions create a channel by which inflation can positively influence real activity. This feature also creates the possibility of multiple steady state equilibria. We also analyze the impact of inflation on capital accumulation, the role search frictions play in determining the extent to which inflation distorts relative prices, and the effect of money growth on firm entry on trade friction. In doing so, we demonstrate that a multiple matching model of money is amendable to study a wide range of traditional issues in monetary theory.Inflation (Finance) ; Money ; Econometric models

A novel haptic model and environment for maxillofacial surgical operation planning and manipulation

This paper presents a practical method and a new haptic model to support manipulations of bones and their segments during the planning of a surgical operation in a virtual environment using a haptic interface. To perform an effective dental surgery it is important to have all the operation related information of the patient available beforehand in order to plan the operation and avoid any complications. A haptic interface with a virtual and accurate patient model to support the planning of bone cuts is therefore critical, useful and necessary for the surgeons. The system proposed uses DICOM images taken from a digital tomography scanner and creates a mesh model of the filtered skull, from which the jaw bone can be isolated for further use. A novel solution for cutting the bones has been developed and it uses the haptic tool to determine and define the bone-cutting plane in the bone, and this new approach creates three new meshes of the original model. Using this approach the computational power is optimized and a real time feedback can be achieved during all bone manipulations. During the movement of the mesh cutting, a novel friction profile is predefined in the haptical system to simulate the force feedback feel of different densities in the bone

Author Correction: Fermiology and electron dynamics of trilayer nickelate La4Ni3O10.

The original version of this Article contained errors in Fig. 2, Fig. 3a-c and Supplementary Fig. 2. In Fig. 2g and Supplementary Fig. 2, the band structure plot calculated from density function theory (DFT) had a missing band of mainly z2 character that starts at about - 0.25 eV at the Y point and disperses downwards towards the Γ point. This band was inadvertently neglected when transferring the lines from the original band plot to the enhanced version for publication. Also in Fig. 2g, the points labelled M and Y were not exactly at (1/2 1/2 0) and (0 1/2 0), but rather (0.52 0.48 0) and (0 0.48 0) due to a bug in XCrysDen for low-symmetry structures that the authors failed to identify before publication. Thus, the bands presented were slightly off the true M-Y direction and additional splitting incorrectly appeared (in particular for the highly dispersive bands of x2-y2 character). The correct versions of Fig. 2g (cited as Fig. 1) and Supplementary Fig. 2 (cited as Fig. 2) are:which replaces the previous incorrect version, cited here as Fig. 3 and Fig. 4:Neither of these errors in Fig. 2g or Supplementary Fig. 2 affects either the discussion or any of the interpretations of the ARPES data provided in the paper. The authors discussed the multilayer band splitting along the Γ-M direction (δ band and α band as assigned in the paper), and ARPES did not see any split band. The authors did not discuss the further splitting that arises due to back folding along the M-Y direction.In Fig. 3a-c, the errors in the M and Y points in Fig. 2g cause subtle changes to the DFT dispersions. The correct version of Fig. 3a-c is cited here as Fig 5:which replaces the previous incorrect version (Fig. 6):However, the influence on the effective mass results of Fig. 3d is negligible.These errors have now been corrected in both the PDF and HTML versions of the Article. The authors acknowledge James Rondinelli and Danilo Puggioni from Northwestern University for calling our attention to these issues

High density NV sensing surface created via He^(+) ion implantation of (12)^C diamond

We present a promising method for creating high-density ensembles of nitrogen-vacancy centers with narrow spin-resonances for high-sensitivity magnetic imaging. Practically, narrow spin-resonance linewidths substantially reduce the optical and RF power requirements for ensemble-based sensing. The method combines isotope purified diamond growth, in situ nitrogen doping, and helium ion implantation to realize a 100 nm-thick sensing surface. The obtained 10^(17) cm^(-3) nitrogen-vacancy density is only a factor of 10 less than the highest densities reported to date, with an observed spin resonance linewidth over 10 times more narrow. The 200 kHz linewidth is most likely limited by dipolar broadening indicating even further reduction of the linewidth is desirable and possible.Comment: 5 pages including references. 3 figure

Chronic thoracic hemisection spinal cord injury in adult rats induces a progressive decline in transmission from uninjured fibers to lumbar motoneurons

Although most spinal cord injuries are anatomically incomplete, only limited functional recovery has been observed in people and rats with partial lesions. To address why surviving fibers cannot mediate more complete recovery, we evaluated the physiological and anatomical status of spared fibers after unilateral hemisection (HX) of thoracic spinal cord in adult rats. We made intracellular and extracellular recordings at L5 (below HX) in response to electrical stimulation of contralateral white matter above (T6) and below (L1) HX. Responses from T6 displayed reduced amplitude, increased latency and elevated stimulus threshold in the fibers across from HX, beginning 1-2 weeks after HX. Ultrastructural analysis revealed demyelination of intact axons contralateral to the HX, with a time course similar to the conduction changes. Behavioral studies indicated partial recovery which arrested when conduction deficits began. These findings suggest a chronic pathological state in intact fibers and necessity for prompt treatment to minimize it

Network-coding-based Cooperative V2V Communication in Vehicular Cloud Networks

Chinacom 2018 - 13th EAI International Conference on Communications and Networking in China, 23-25 October 2018, Chengdu, ChinaThis is the author accepted manuscript. the final version is available from Springer Verlag via the DOI in this recordWe investigate the potential of applying cooperative relaying and network coding techniques to support vehicle-to-vehicle (V2V) communication in vehicular cloud networks (VCN). A reuse-mode MIMO content distribution system with multiple sources, multiple relays, and multiple destinations under Nakagami-m fading is considered. We apply a class of finite field network codes in the relays to achieve high spatial diversity in an efficient manner and derive the system communication error probability that the destinations fail to recover the desired source messages. The results show that our method can improve the performance over conventional data transmission solutions