67 research outputs found
Inter-Regional Trade and Lobbying
In a federation, local policies with inter-regional spillovers depend on the extent and the nature of local capture. Local lobbyists who have multi-regional scope internalize inter-jurisdictional externalities to a larger extent than the lobbyists with interests in a single region. In particular, multi-regional industrial groups lobby for lower interregional trade barriers than local industrial lobbies. The results are based on a simple model, case-study evidence, and econometric analysis of micro-level panel data from Russia. Controlling for firm-level fixed effects, the performance of firms increases with an increase in the number of neighboring regions captured by multiregional groups. The paper has implications for international trade: lobbying by multinationals should lead to lower protectionism compared to lobbying by national corporations.
Effects of Spatial Dispersion on Reflection from Mushroom-type Artificial Impedance Surfaces
Several recent works have emphasized the role of spatial dispersion in wire
media, and demonstrated that arrays of parallel metallic wires may behave very
differently from a uniaxial local material with negative permittivity. Here, we
investigate using local and non-local homogenization methods the effect of
spatial dispersion on reflection from the mushroom structure introduced by
Sievenpiper. The objective of the paper is to clarify the role of spatial
dispersion in the mushroom structure and demonstrate that under some conditions
it is suppressed. The metamaterial substrate, or metasurface, is modeled as a
wire medium covered with an impedance surface. Surprisingly, it is found that
in such configuration the effects of spatial dispersion may be nearly
suppressed when the slab is electrically thin, and that the wire medium can be
modeled very accurately using a local model. This result paves the way for the
design of artificial surfaces that exploit the plasmonic-type response of the
wire medium slab.Comment: submitted for publication, under revie
Preperitoneal Blockade in the Treatment of Patients with Perforated Gastroduodenal Ulcers and Peritonitis
The objective of this study was to improve the results of surgical treatment for patients with perforated gastroduodenal ulcers and peritonitis (PGDU-P) by applying the preperitoneal blockade.
Materials and Methods: The study included 102 patients with perforated gastroduodenal ulcers (PGDU) complicated by peritonitis. Patients between 18 and 30 years were predominant. Pain was measured using the Visual Analog Scale (VAS) for Pain. The measurements of intra-abdominal pressure (IAP) by indirect infravesical tensometry were performed daily from the first day after the operation. Surgical interventions (laparotomy, laparoscopic suturing of PGDU, sanitation and drainage of the abdominal cavity) was performed under endotracheal anesthesia in all patients. Patients were divided into two groups depending on the method of postoperative analgesia. Patients of Group 1 (n=62) were subjected only to systemic opioid analgesia (an intramuscular injection of 1% solution of Promedol 1ml 4 times a day). Patients of Group 2 were subjected to systemic opioid analgesia and catheterization of the preperitoneal space for infusion of 0.5% solution of Novocaine in the postoperative period.
Results: Postoperative analgesia using preperitoneal blockade after laparotomy and suturing of perforated gastroduodenal ulcers reduced the pain intensity by 2 times in comparison with conventional analgesia. The preperitoneal blockade after laparotomy in PGDU-P patients promotes the effective reduction of intra-abdominal hypertension (IAH) for 2 days. The comparative evaluation of the incidence of the early postoperative complications showed that using preperitoneal blockade contributed to significantly reducing the complications in Group 2. Postoperative mortality was 1.6% in Group 1 and 0 in Group 2. The average length of stay was reduced by approximately 3 days in Group 2 compared to traditional anesthesia
Analysis of Keyless Massive MIMO-based Cryptosystem Security
A cryptosystem for wireless communications, recently proposed by T.~Dean and A.~Goldsmith, is considered. That system can be regarded as a second revolution in cryptography because the confidentiality of the messages transmitted over a wireless massive MIMO-based channel is provided by the difference in the space locations of legal and illegal users and it does not require any secret key distribution. However our investigation shows that there is a chance of eavesdropping the cipher texts by using a suboptimal algorithm. Therefore we investigate some additional conditions for channel matrices and additive noises in order to provide a desired security. A combination of wiretap channel coding with a MIMO-based cryptosystem is also considered
Anomalous microwave response in the dissipative regime of topological superconducting devices based on Bi2Te2.3Se0.7
Superconducting proximity junctions based on topological insulators are
widely believed to harbor Majorana-like bound states. The latter serves as a
paradigm non-local topological quantum computation protocols. Nowadays, a
search for topological phases in different materials, perspective for a
realization of topological qubits, is one of the central efforts in quantum
physics. It is motivated, in particular, by recent observation of anomalous ac
Josephson effect, which being a signature of Majorana physics. Its
manifestations, such as a fractional Josephson frequency and the absence of the
first (or several odd in more rare cases), Shapiro steps, were reported for
different materials. Here we study Shapiro steps in Nb/Bi2Te2.3Se0.7/Nb
junctions, based on ultrasmall single crystals of a 3D topological insulator
synthesized by a physical vapor deposition (PVD) technique. We present evidence
that our junctions are ballistic. When subjected to microwave radiation, the
junctions exhibit Shapiro steps, but the first step is missing. Typically it is
assumed that the missing first step (MFS) effect cannot be observed in the
presence of quasiparticle poisoning due to suppression of the 4{\pi}-periodic
component. Our findings within the context of the RSJ-model of Josephson
junction dynamics show that such behaviour of samples corresponds to a specific
condition, requiring a minimum of 5% of the 4{\pi}-component for disappearance
of the first Shapiro step.Comment: Keywords: Shapiro step missing, Topological insulator,
Superconductivity, Ballistic transport, 4{\pi}-periodic componen
Electrochemical reduction of multilayer graphene oxide in alkaline electrolyte
The results of the study of the electrochemical reduction of multilayer graphene oxide in the potentiostatic mode are presented and the possibility of using alkaline electrolyte (KOH) with the concentration below 0.1 M is shown. The identification of the electrochemically reduced graphene oxide was carried out using the XRD, FTIR and Raman-spectroscopy methods. Applying the method of Raman spectroscopy the increase in the intensity of the G and 2D bands, indicating the formation of few-layer forms of reduced graphene oxide was found. The surface morphology of the electrochemically reduced graphene oxide was studied by means of the SEM method
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