Search results for " Lower"

Sea level and climate forcing of the Sr isotope composition of late Miocene Mediterranean marine basins

2014

Sr isotope records from marginal marine basins track the mixing between seawater and local continental runoff, potentially recording the effects of sea level, tectonic, and climate forcing in marine fossils and sediments. Our 110 new Sr-87/Sr-86 analyses on oyster and foraminifera samples from six late Miocene stratigraphic sections in southern Turkey, Crete, and Sicily show that Sr-87/Sr-86 fell below global seawater values in the basins several million years before the Messinian Salinity Crisis, coinciding with tectonic uplift and basin shallowing. 87Sr/86Sr from more centrally located basins (away from the Mediterranean coast) drop below global seawater values only during the Messinian S…

2014

This paper deals with the problem of robust model predictive control (RMPC) for a class of linear time-varying systems with constraints and data losses. We take the polytopic uncertainties into account to describe the uncertain systems. First, we design a robust state observer by using the linear matrix inequality (LMI) constraints so that the original system state can be tracked. Second, the MPC gain is calculated by minimizing the upper bound of infinite horizon robust performance objective in terms of linear matrix inequality conditions. The method of robust MPC and state observer design is illustrated by a numerical example.

Long-term results of conventional myotomy in patients with achalasia: a prospective 20-year analysis.

2006

Myotomy has proved to be an efficient primary therapy in patients with achalasia, especially in younger patients (<40 years of age). The results of laparoscopic myotomy cannot be finally assessed, on account of the shorter postoperative follow-up. Thus, there are considerable data regarding intermediate-term outcomes after laparoscopic myotomy. The aim of our study was a 20-year analysis of the conventional cardiomyotomy as the underlying basis assessing the results of minimal-invasive surgery. Within 20 years (September 1985 through September 2005), 161 operations for achalasia were performed in our clinic. Enrolled in this study were 108 patients with a conventional, transabdominal myotom…

Effects of pneumatic dilation and myotomy on esophageal function and morphology in patients with achalasia.

2005

Only two treatment modalities–pneumatic dilation and Heller myotomy–promise long-term relief from dysphagia and regurgitation in patients with achalasia. The objective of this study was to determine whether both options differ in their effects on esophageal function, morphology, and improvement in symptoms. Eighty-nine patients diagnosed with achalasia between January 1980 and December 2002 at a single center were enrolled in this study. Sixty-four patients underwent pneumatic dilation and 25 Heller myotomy in combination with an anterior semifundoplication (Dor procedure). Clinical evaluation (Eckardt-Score), esophageal manometry, and barium swallow were performed before and within 6 mont…

Deciphering the Macroeconomic Effects of Internal Devaluations in a Monetary Union

2020

We study the macroeconomic effects of internal devaluations undertaken by a periphery of countries belonging to a monetary union. We find that internal devaluations have large and positive output effects in the long run. Through an expectations channel, most of these effects carry over to the short run. Internal devaluations focused on goods markets reforms are generally more powerful in stimulating growth than reforms aimed at moderating wages, but the latter are less deflationary. For a monetary union with a periphery the size of the euro area's, the countries at the periphery benefit from internal devaluations even at the zero lower bound (ZLB) of the nominal interest rate. Nevertheless,…

LCRT: A ToA Based Mobile Terminal Localization Algorithm in NLOS Environment

2009

©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Article also available from publisher: http://dx.doi.org/10.1109/VETECS.2009.5073644 Non line-of-sight (NLOS) propagation in range measurement is a key problem for mobile terminal localization. This paper proposes a low computational residual test (LCRT) algorithm that can identify the number of line-of-sight (LOS) transmissions and reduce the computational com…

A kriging interpolation strategy for the optimization of Acidithiobacillus ferrooxidans biomass production using fed-batch bioreactors

2008

In this work, a procedure for the optimization of Acidithiobacillus ferrooxidans biomass production in fed-batch reactors using a model based on optimal spatial interpolation of experimental data is proposed. The approach is useful in those cases where specific growth and substrate consumption rates are unknown. Based on interpolation, the optimal values of biomass and substrate concentrations set points are obtained at the minimum of 2-dimensional cost function. In the fed-batch reactor biomass and substrate concentrations are controlled at their set points by changing the input flow and its concentration. We propose a minimum variance control strategy which improves the classical proporti…

Large two-dimensional electronic systems: Self-consistent energies and densities at low cost

2013

We derive a self-consistent local variant of the Thomas-Fermi approximation for (quasi-) two-dimensional (2D) systems by localizing the Hartree term. The scheme results in an explicit orbital-free representation of the electron density and energy in terms of the external potential, the number of electrons, and the chemical potential determined upon normalization. We test the method over a variety 2D nanostructures by comparing to the Kohn-Sham 2D local-density approximation (LDA) calculations up to 600 electrons. Accurate results are obtained in view of the negligible computational cost. We also assess a local upper bound for the Hartree energy. Peer reviewed

Quantum algorithms for search with wildcards and combinatorial group testing

2012

We consider two combinatorial problems. The first we call "search with wildcards": given an unknown n-bit string x, and the ability to check whether any subset of the bits of x is equal to a provided query string, the goal is to output x. We give a nearly optimal O(sqrt(n) log n) quantum query algorithm for search with wildcards, beating the classical lower bound of Omega(n) queries. Rather than using amplitude amplification or a quantum walk, our algorithm is ultimately based on the solution to a state discrimination problem. The second problem we consider is combinatorial group testing, which is the task of identifying a subset of at most k special items out of a set of n items, given the…

Neutrino Mass from Cosmology

2012

Neutrinos can play an important role in the evolution of the Universe, modifying some of the cosmological observables. In this contribution we summarize the main aspects of cosmological relic neutrinos and we describe how the precision of present cosmological data can be used to learn about neutrino properties, in particular their mass, providing complementary information to beta decay and neutrinoless double-beta decay experiments. We show how the analysis of current cosmological observations, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure, provides an upper bound on the sum of neutrino masses of order 1 eV or less, with very good p…