Observing the intrinsic linewidth of a quantum-cascade laser: beyond the Schawlow-Townes limit

A comprehensive investigation of the frequency-noise spectral density of a free-running mid-infrared quantum-cascade laser is presented for the first time. It provides direct evidence of the leveling of this noise down to a white noise plateau, corresponding to an intrinsic linewidth of a few hundred Hz. The experiment is in agreement with the most recent theory on the fundamental mechanism of line broadening in quantum-cascade lasers, which provides a new insight into the Schawlow-Townes formula and predicts a narrowing beyond the limit set by the radiative lifetime of the upper level.Comment: 4 pages, 4 figure

Transparency, Civic Capital and Political Accountability: A Virtuous Relation?

Our paper investigates the intertwined relation among transparency, civic capital and political accountability in a large sample of Italian municipalities using a new indicator of institutional transparency. Firstly, we test the hypothesis that civic capital affects transparency of public administrations; secondly, we verify whether in municipalities where civic capital is high, citizens’ attention toward government accountability is also high, making it politically unfeasible to disregard the demand for transparency. We find that civic capital positively affects transparency and the latter, in turn, is politically rewarding for the local administrators only conditional to the level of civic capital. Our findings are robust to different samples and endogeneity concerns

Cooling Flows of Self-Gravitating, Rotating, Viscous Systems

We obtain self-similar solutions that describe the dynamics of a self-gravitating, rotating, viscous system. We use simplifying assumptions; but explicitly include viscosity and the cooling due to the dissipation of energy. By assuming that the turbulent dissipation of energy is as power law of the density and the speed v_{rms} and for a power-law dependence of viscosity on the density, pressure, and rotational velocity, we investigate turbulent cooling flows. It has been shown that for the cylindrically and the spherically cooling flows the similarity indices are the same, and they depend only on the exponents of the dissipation rate and the viscosity model. Depending on the values of the exponents, which the mechanisms of the dissipation and viscosity determine them, we may have solutions with different general physical properties. The conservation of the total mass and the angular momentum of the system strongly depends on the mechanisms of energy dissipation and the viscosity model.Comment: 19 pages, 5 figures, To appear in ApJ (scheduled for the v574, July 20, 2002

Multi-Centered Black Hole Flows

We describe the systematical construction of the first order formalism for multi-centered black holes with flat three dimensional base-space, within the so-called $T^{3}$ model of N=2, D=4 ungauged Maxwell-Einstein supergravity. The three possible flow classes (BPS, composite non-BPS and almost-BPS) are analyzed in detail, and various solutions, such as single-centered (static or under-rotating) and all known multi-centered black holes, are recovered in this unified framework. We also consider the possibility of obtaining new solutions. The almost-BPS class is proved to split into two general sub-classes, corresponding to a positive or negative value of the duality-invariant polynomial for the total charge; the well known almost BPS system is shown to be a particular solution of the second sub-class.Comment: 17 pages,no figure

Low-Mass Star Formation, Triggered by Supernova in Primordial Clouds

The evolution of a gas shell, swept by the supernova remnant of a massive first generation star, is studied with H_2 and HD chemistry taken into account. When a first-generation star explodes as a supernova, H_2 and HD molecules are formed in the swept gas shell and effectively cool the gas shell to temperatures of 32 K - 154 K. If the supernova remnant can sweep to gather the ambient gas, the gas shell comes to be dominated by its self-gravity, and hence, is expected to fragment. Our result shows that for a reasonable range of temperatures (200 K - 1000 K) of interstellar gas, the formation of second-generation stars can be triggered by a single supernova or hypernova.Comment: 38pages, 10 figures, The Astrophysical Journal, accepted 8 Dec. 200

CTLA-4 rs231775 and risk of acute renal graft rejection: an updated meta-analysis with trial sequential analysis

Contrasting results exist on the association between CTLA-4 rs231775 and acute rejection in kidney transplant recipients. We herein conducted an updated systematic review with meta-analysis and trial sequential analysis (TSA) to clarify this relationship and to establish whether the current evidence is sufficient to draw firm conclusions. In addition, noteworthiness of significant pooled odds ratios (ORs) was estimated by false positive report probability (FPRP). A comprehensive search was performed through PubMed, Web of Knowledge, Cochrane Library and Open Grey up to October 2019. Fifteen independent cohorts, including a total of 5,401 kidney transplant recipients, were identified through the systematic review. Overall, no association was detected with the allelic (OR 1.07, 95% CI 0.88\u20131.30, P = 0.49), dominant (OR 0.94, 95% CI 0.73\u20131.22, P = 0.66) or the recessive (OR 1.18, 95% CI 0.97\u20131.43, P = 0.096) model of CTLA-4 rs231775. In each genetic model, the cumulative Z-curve in TSA crossed the futility boundary and entered the\ua0futility\ua0area. In addition, none of the significant genetic comparisons detected in the subsequent and sensitivity analyses or in previously reported meta-analyses were found to be noteworthy by FPRP. In conclusion, this study provides strong evidence that CTLA-4 rs231775 is not a clinically-relevant genetic risk determinant of acute rejection after renal transplantation

Contribució al coneixement de la família Lepiotaceae Roze de les Illes Balears (IV) : una espècie poc coneguda: Lepiota andegavensis Mornand

Contribució al coneixement de la família Lepiotaceae Roze a les Illes Balears (IV). Una espècie poc coneguda: Lepiota andegavensis Mornand. Se cita i descriu per primera vegada tant per a les Balears com per a l'estat espanyol, Lepiota andegavensis Mornand; a més, s'aporten notes sobre la seva taxonomia, ecologia i distribució.Contribut ion to our knowledge of the fam. Lepiotaceae Roze from the Balearic Islands (Spain) IV. A rare species: Lepiota andegavensis Mornand. Lepiota andegavensis Mornand is described for the first time for the Balearic Is. (Western Mediterranean) and also for Spain, with remarks added on its taxonomy, ecology and distribution.Contribución al conocimiento de la familia Lepiotaceae Roze en las Islas Baleares (IV). Una espécie poco conocida: Lepiota andegavensis Mornand. Se cita y se describe por primera vez para las Islas Baleares y para España, Lepiota andegavensis Mornand; ademàs, se aportan datos sobre su taxonomia,ecología y distribución

Contribució al coneixement de la família Lepiotaceae Roze de les Illes Balears (IV) : una espècie poc coneguda: Lepiota andegavensis Mornand

Contribució al coneixement de la família Lepiotaceae Roze a les Illes Balears (IV). Una espècie poc coneguda: Lepiota andegavensis Mornand. Se cita i descriu per primera vegada tant per a les Balears com per a l'estat espanyol, Lepiota andegavensis Mornand; a més, s'aporten notes sobre la seva taxonomia, ecologia i distribució.Contribución al conocimiento de la familia Lepiotaceae Roze en las Islas Baleares (IV). Una espécie poco conocida: Lepiota andegavensis Mornand. Se cita y se describe por primera vez para las Islas Baleares y para España, Lepiota andegavensis Mornand; ademàs, se aportan datos sobre su taxonomia,ecología y distribución.Contribut ion to our knowledge of the fam. Lepiotaceae Roze from the Balearic Islands (Spain) IV. A rare species: Lepiota andegavensis Mornand. Lepiota andegavensis Mornand is described for the first time for the Balearic Is. (Western Mediterranean) and also for Spain, with remarks added on its taxonomy, ecology and distribution