Ring-theoretic properties of PVMDs

We extend to Pr\"ufer $v$-multiplication domains some distinguished ring-theoretic properties of Pr\"ufer domains. In particular we consider the t##-property, the $t$-radical trace property, $w$-divisoriality and $w$-stability.Comment: 15 pages, to appear in Communications in Algebr

w-Divisorial Domains

We study the class of domains in which each w-ideal is divisorial, extending several properties of divisorial and totally divisorial domains to a much wider class of domains. In particular we consider PvMDs and Mori domains

On the Convergence Speed of Turbo Demodulation with Turbo Decoding

Iterative processing is widely adopted nowadays in modern wireless receivers for advanced channel codes like turbo and LDPC codes. Extension of this principle with an additional iterative feedback loop to the demapping function has proven to provide substantial error performance gain. However, the adoption of iterative demodulation with turbo decoding is constrained by the additional implied implementation complexity, heavily impacting latency and power consumption. In this paper, we analyze the convergence speed of these combined two iterative processes in order to determine the exact required number of iterations at each level. Extrinsic information transfer (EXIT) charts are used for a thorough analysis at different modulation orders and code rates. An original iteration scheduling is proposed reducing two demapping iterations with reasonable performance loss of less than 0.15 dB. Analyzing and normalizing the computational and memory access complexity, which directly impact latency and power consumption, demonstrates the considerable gains of the proposed scheduling and the promising contributions of the proposed analysis.Comment: Submitted to IEEE Transactions on Signal Processing on April 27, 201

Semistar Dedekind Domains

Let $D$ be an integral domain and $\star$ a semistar operation on $D$. As a generalization of the notion of Noetherian domains to the semistar setting, we say that $D$ is a $\star$--Noetherian domain if it has the ascending chain condition on the set of its quasi--$\star$--ideals. On the other hand, as an extension the notion of Pr\"ufer domain (and of Pr\"{u}fer $v$--multiplication domain), we say that $D$ is a Pr\"ufer $\star$--multiplication domain (P$\star$MD, for short) if $D_M$ is a valuation domain, for each quasi--$\star_{_{f}}$--maximal ideal $M$ of $D$. Finally, recalling that a Dedekind domain is a Noetherian Pr\"{u}fer domain, we define a $\star$--Dedekind domain to be an integral domain which is $\star$--Noetherian and a P$\star$MD. In the present paper, after a preliminary study of $\star$--Noetherian domains, we investigate the $\star$--Dedekind domains. We extend to the $\star$--Dedekind domains the main classical results and several characterizations proven for Dedekind domains. In particular, we obtain a characterization of a $\star$--Dedekind domain by a property of decomposition of any semistar ideal into a ``semistar product'' of prime ideals. Moreover, we show that an integral domain $D$ is a $\star$--Dedekind domain if and only if the Nagata semistar domain Na$(D, \star)$ is a Dedekind domain. Several applications of the general results are given for special cases of the semistar operation $\star$

Damping-off of wheat by Fusarium culmorum (W.G. Sm.) Sacc., and its control

Imperial Users onl

First Report of Ventriculoperitoneal Shunt Infection due to Cyberlindnera fabianii.

Fungal infections in the central nervous system (CNS) are associated with significant morbidity and death. Transient fungemia in immunocompetent patients without any other risk factors for fungemia has been suggested as a possible mechanism that may lead to serious fungal ventriculoperitoneal (VP) shunt infections, but evidence is lacking. The clinical spectrum, diagnosis, and optimal therapy of Cyberlindnera fabianii infections remain to be determined. We describe the first case of CNS infection due to C. fabianii that occurred in an immunocompetent adult with a VP shunt. Spontaneous translocation with yeast that is not part of the normal gastrointestinal flora in the setting of ingestion of multiple servings of a fermentation product was the likely source from which Cyberlindnera fabianii gained entrance into the VP shunt system, causing meningitis in this patient. The authors conclude that, in view of the high morbidity associated with yeast infection of the CNS, long-term antifungal therapy should be strongly considered in cases where the VP shunt cannot be completely removed. Transient fungemia may lead to invasive disease in an immunocompetent host with VP shunt, even in the absence of any other risk factors for fungemia and even after remote placement of the VP shunt

Adiabatic DC-AC Power Converter with 99% Efficiency

This paper describes a novel approach to building a high efficiency and dimensionally compact power converter / inverter. A prototype was built for the Google / IEEE Little Box competition. The converter takes a 400-450 V DC input and creates a single-phase 230V AC output. It is capable of supplying 2kW continuously to a load. The design is based on a multi-winding DC-DC active transformer operating at around 500 kHz. The AC output sinewave is synthesized by switching between the DC tap levels produced by the active transformer. The transformer MOSFETs operate under ZVS and have an adiabatic gate driver. Early tests on the prototype demonstrate a high fidelity sinewave output and very high efficiency (better than 99%)

Ehteshami, Anoushiravan. Iran: Stuck in Transition. London and New York: Routledge, 2017.

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