521 research outputs found

    Monetary policy and financial market evolution

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    Monetary policy ; Financial markets

    Equity markets, transaction costs, and capital accumulation

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    There is a close, if imperfect, relationship between the effectiveness of an economy's capital markets and its level (or rate of growth) of real development. This may be because financial markets provide liquidity, promote the sharing of information, or permit agents to specialize. There is literature about how these functions help increase real activity, but surprisingly little literature predicting how the volume of activity in financial markets relates to the level or efficiency of an economy's productive activity. The authors address this question: how does the efficiency of an economy's equity market -- as measured by transaction costs -- affect its efficiency in producing physical capital and, through this channel, final goods and services? The answer: As the efficiency of an economy's capital markets increases (that is, as the transaction costs fall), the general effect is to cause agents to make longer-term -- hence, more transction-intensive -- investments. The result is a higher rate of return on savings and a change in its composition. These general equilibrium effects on the composition of savings cause agents to hold more of their wealth in the form of existing equity claims and to invest less in the initiation of new capital investments. As a result, a reduction in transaction costs can cause the capital stock either to rise or fall (under scenarios described in the paper). Further, a reduction in transaction costs will typically alter the composition of saving and investment, and any analysis of the consequences of such changes must take those effects into account.International Terrorism&Counterterrorism,Economic Theory&Research,Environmental Economics&Policies,Payment Systems&Infrastructure,Banks&Banking Reform,Economic Theory&Research,Environmental Economics&Policies,Banks&Banking Reform,International Terrorism&Counterterrorism,Trade and Regional Integration

    Signature of a polyamorphic transition in the THz spectrum of vitreous GeO2

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    The THz spectrum of density fluctuations, S(Q,ω)S(Q, \omega), of vitreous GeO2_2 at ambient temperature was measured by inelastic x-ray scattering from ambient pressure up to pressures well beyond that of the known α\alpha-quartz to rutile polyamorphic (PA) transition. We observe significant differences in the spectral shape measured below and above the PA transition, in particular, in the 30-80 meV range. Guided by first-principle lattice dynamics calculations, we interpret the changes in the phonon dispersion as the evolution from a quartz-like to a rutile-like coordination. Notably, such a crossover is accompanied by a cusp-like behavior in the pressure dependence of the elastic response of the system. Overall, the presented results highlight the complex fingerprint of PA phenomena on the high-frequency phonon dispersion.Comment: 18 pages, 5 figure

    Acute bleeding obstruction pancreatitis after Roux-en-Y anastomosis in total gastrectomy: a single center experience

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    Anastomotic intraluminal bleeding is a well-known complication after total gastrectomy. Nevertheless, few data are published on acute bleeding obstruction pancreatitis (BOP) due to a bleeding from the jejunojejunostomy (JJ). In this paper we describe our experience. A total of 140 gastrectomies for EGJ cancer were performed in our Institute from January 2012 to January 2017. All reconstructions were performed with a Roux-en-Y anastomosis: a mechanical end-to-side esophago-jejunostomy and a mechanical end-to-side JJ. Three patients suffered from a bleeding at the JJ with a consequent BOP. We analyzed the time of diagnosis, the treatment and the outcomes. The three patients presented anemia at the laboratory findings on postoperative day (POD) 1. In patient I laboratory findings of acute pancreatitis were found in POD 2. CT scan was performed and showed signs of BOP. Endoscopic treatment was tried without success. Therefore, patient underwent surgery: JJ take down, bleeding control and anastomosis rebuild were performed. In spite of this the patient died of MOF in POD 4. Patient II had a persistent anemia treated with blood transfusions until POD 3, when laboratory tests showed increased lipase and bilirubin levels. Patient was successfully treated with endoscopy but several blood transfusions and a prolonged recovery were necessary. Patient III had laboratory findings of acute pancreatitis on POD 1. Immediate surgery was performed and patient was discharged on POD 9 without sequelae. BOP is a rare but deadly complication after Roux-en-Y anastomosis. An early diagnosis and an aggressive treatment seem to improve the outcome

    Unemployment, migration, and growth

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    Economic development is typically accompanied by a very pronounced migration of labor from rural to urban employment. This migration, in turn, is often associated with large scale urban underemployment. Both factors appear to play a very prominent role in the process of development. We consider a model in which rural-urban migration and urban underemployment are integrated into an otherwise conventional neoclassical growth model. Unemployment arises not from any exogenous rigidities, but from an adverse selection problem in labor markets. We demonstrate that, in the most natural case, rural-urban migration - and its associated underemployment - can be a source of multiple, asymptotically stable steady state equilibria, and hence of development traps. They also easily give rise to an indeterminacy of perfect foresight equilibrium, as well as to the existence of a large set of periodic equilibria displaying undamped oscillation. Many such equilibria display long periods of uninterrupted growth and rural-urban migration, punctuated by brief but severe recessions associated with net migration from urban to rural employment. Such equilibria are argued to be broadly consistent with historical U.S. experience.Unemployment

    Optical constants modelling in silicon nitride membrane transiently excited by EUV radiation.

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    We hereby report on a set of transient optical reflectivity and transmissivity measurements performed on silicon nitride thin membranes excited by extreme ultraviolet (EUV) radiation from a free electron laser (FEL). Experimental data were acquired as a function of the membrane thickness, FEL fluence and probe polarization. The time dependence of the refractive index, retrieved using Jones matrix formalism, encodes the dynamics of electron and lattice excitation following the FEL interaction. The observed dynamics are interpreted in the framework of a two temperature model, which permits to extract the relevant time scales and magnitudes of the processes. We also found that in order to explain the experimental data thermo-optical effects and inter-band filling must be phenomenologically added to the model

    Short-wavelength four wave mixing experiments using single and two-color schemes at FERMI

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    The development of ultra-bright extreme ultraviolet (EUV) and X-ray free electron laser (FEL) sources has enabled the extension of wave-mixing approaches into the short wavelength regime. Such a class of experiments relies upon nonlinear interactions among multiple light pulses offering a unique tool for exploring the dynamics of ultrafast processes and correlations between selected excitations at relevant length and time scales adding elemental and site selectivity as well. Besides the availability of a suitable photon source, the implementation of wave mixing methodology requires efforts in developing the instrumental set-up. We have realized at the FERMI FEL two dedicated set-ups to handle multiple FEL beams with preselected parameters in a non-collinear fashion and control their interaction sequence at the target. These unique apparatuses, combined with the exceptional characteristics of the seeded FERMI FEL, have allowed us to make the first steps into this field and further advances are foreseen in the near future

    Free electron laser-driven ultrafast rearrangement of the electronic structure in Ti

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    High-energy density extreme ultraviolet radiation delivered by the FERMI seeded free-electron laser has been used to create an exotic nonequilibrium state of matter in a titanium sample characterized by a highly excited electron subsystem at temperatures in excess of 10 eV and a cold solid-density ion lattice. The obtained transient state has been investigated through ultrafast absorption spectroscopy across the Ti M2,3-edge revealing a drastic rearrangement of the sample electronic structure around the Fermi level occurring on a time scale of about 100 fs

    The newtonian approach in the meteorological tide waves forecasting: preliminary observations in the East Ligurian harbours

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    Sea level oscillations are the superposition of many contributions, among which the main are astronomic and meteorological low-frequency tides. In Ligurian Sea meteo-tide components, being most ample than astronomic fluctuations, drive water exchange in harbours. The present note shows first results about port of Genoa concerning a coherency study between atmospheric variation and corresponding sea level adjustment (meteorological tide). The newtonian forecasting method of meteorological tides is based on measurements of time elapsing between barometric sea level unbalance (Δg) and its meteorological tide compensation (inverse barometer component). Meteorological tide component is independent on the Earth-Moon-Sun gravitational relationships, moreover parameters related to the shifted water mass are too many to describe the phenomenon analytically (basin topography, barometric strength position and time, chemical water quality, off-shore sea circulation, etc.); then, meteorological tide can’t be accurately foreseen by atmospheric pressure measurements only. A gravimeter can detect the geodetic unbalance starting time and a tide-gauge can detect the newtonian compensation (tide wave) coming time. The difference between these two times is the meteorological tide delay. An opportune statistic of this delay provides an experimental law typical for each harbour to forecast the meteo-tide compensation wave delay. This paper describes the methodological procedure adopted and first evidences of the phenomenon in Genoa harbour

    The hERG1 potassium channel behaves as prognostic factor in gastric dysplasia endoscopic samples

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    Purpose: Gastric cancer (GC) is still a relevant health issue worldwide. The identification of prognostic factors for progression of gastric dysplasia (GD), the main pre-cancerous lesion of the intestinal-type GC, is hence mandatory.Patients and methods: A cohort of 83 GD endoscopic samples belonging to Italian subjects was collected. hERG1 expression was evaluated by immunohistochemistry and scored 0-3, depending on the percentage of stained cells. Expression data were analysed in conjunction with clinico-pathological and survival data.Results: hERG1 turned out to be expressed in 67.47% (56 out of 83) of the GD samples. hERG1 expression was higher in high-grade GD compared to low-grade GD (29 out of 39, 74.36% vs 27 out of 44, 61.36%), although the statistical significance was not reached (P=0.246). No association emerged between hERG1 expression and clinical features of the patients (age, gender, localization, H. pylori infection, gastritis and intestinal metaplasia). In a subset of cases for which sequential samples of gastric lesions (from GD to Early Gastric Cancer and Advanced Gastric Cancer) were available, hERG1 expression was maintained in all the steps of gastric carcinogenesis from GD onwards. A general trend to increased expression in advanced lesions was observed. hERG1 score had a statistically significant impact on both Progression-Free Survival (P=0.018) and Overall Survival (P=0.031). In particular, patients displaying a high hERG1 score have a shorter survival.Conclusion: hERG1 is aberrantly expressed in human GD samples and has an impact on both PFS and OS, hence representing a novel prognostic marker for progression of GD towards GC of the intestinal histotype. Once properly validated, hERG1 detection could be included in the clinical practice, during endoscopic surveillance protocols, for the management of GD at higher risk of progression, as already proposed for Barrett's oesophagus
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