Simulation of Two-Dimensional Fractional Gaussian Noise

Fractional Brownian surfaces have frequently been used to model various physical processes and to generate artificial landscapes. We study a closely related process, called two-dimensional fractional Gaussian noise. We devise a method for generating realizations of this process using an approximate conditioning approach, motivated by results from the corresponding one-dimensional process applied in teletraffic modeling.     

Identification of hydrolysis products of AlCl(3)*6H(2)O in the presence of sulfate by electrospray ionization time-of-flight mass spectrometry and computational methods

ElectroSpray Ionization-Mass Spectrometry (ESI-MS) and computational methods (DFT, MP2, and COSMO) were used to investigate the hydrolysis products of aluminium chloride as a function of sulfate concentration at pH 3.7. With the aid of computational chemistry, structural information was deduced from the chemical compositions observed with ESI-MS. Many novel types of hydrolysis products were noted, revealing that our present understanding of aluminium speciation is too simple. The role of counterions was found to be critical: the speciation of aluminium changed markedly as a function of sulfate concentration. Ab initio calculations were used to reveal the energetically most favoured structures of aluminium sulfate anions and cations selected from the ESI-MS results. Several interesting observations were made. Most importantly, the bonding behaviour of the sulfate group changed as the number of aqua ligands increased. The accompanying structural rearrangement of the clusters revealed the highly active role of sulfate as a ligand. The gas phase calculations were expanded to the aquatic environment using a conductor-like screening model. As expected, the bonding behaviour of the sulfate group in the minimum energy structures was distinctly different in the aquatic environment compared to the gas phase. Together, these methods open a new window for research in the solution chemistry of aluminium species.     

Fast parameterized matching with q-grams

Two strings parameterize match if there is a bijection defined on the alphabet that transforms the first string character by character into the second string. The problem of finding all parameterized matches of a pattern in a text has been studied in both one and two dimensions but the research has been centered on developing algorithms with good worst-case performance. We present algorithms that solve this problem in sublinear time on average for moderately repetitive patterns.     

On improper integrals and differential equations in ordered Banach spaces

In this paper we study the existence of improper integrals of vector-valued mappings. The so obtained results combined with fixed point results in partially ordered functions spaces are then applied to derive existence and comparison results for least and greatest solutions of initial- and boundary-value problems in ordered Banach spaces. The considered problems can be singular, functional, nonlocal, implicit and discontinuous. Concrete examples are also solved.     

On functional improper Volterra integral equations and impulsive differential equations in ordered Banach spaces

In this paper we derive existence and comparison results for discontinuous improper functional integral equations of Volterra type in an ordered Banach space which has a regular order cone. For this purpose we prove Dominated and Monotone Convergence Theorems for improper integrals. The obtained results are then applied to first-order impulsive differential equations. Concrete examples are also solved by using symbolic programming.     

The γ-decay of the 1g92 and 2p inner-hole states in 111Sn via the 112Sn(3He, αγ) reaction at 32 MeV

The γ-decay of the deeply-bound hole states in ¹¹¹Sn has been investigated at 32 MeV incident energy by means of the ¹¹²Sn(³He, αγ) reaction. The α-particles emitted near 0° were detected in a Si counter located at the image plan of the superconducting solenoidal spectrometer SOLENO. The γ-rays in coincidence with the α-particles were detected by two Ge(Li) detectors located at 90° and 142° with respect to the beam direction, respectively. Energies, spins and decay schemes have been established for the low-lying states up to 2.5 MeV excitation energy in ¹¹¹Sn. The γ-decay of the broad bump, located around 4.2 MeV and previously attributed to neutron pick-up from the inner $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{,}\text{and}\text{2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ neutron. Subshells, reveals the importance of quasiparticle-phonon m the spreading mechanism of the inner-hole strengths. The $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ and 2p strength functions have been deduced from the α-decay of the enhanced structures (3 ≦ E_x≦ 8 MeV). They are compared to the ones measured in previous inclusive neutron pick-up experiments and to those calculated in the framework of the quasiparticle-phonon nuclear model.     

Identification and fragmentation of hydrolyzed aluminum species by electrospray ionization tandem mass spectrometry

Earlier characterization of some hydrolysis products of AlCl₃·6H₂O was confirmed by electrospray ionization tandem mass spectrometry with increasing collision energy of projectile ions. At lower collision energies, the aqua ligands were stripped off. At higher energies, two hydroxo groups formed a bridging oxo group with loss of one water molecule. Aluminum complexes could also capture aqua ligands in the collision chamber so long as the parent ion did not fragment, and the fragment ion spectra broadened toward higher m/z values. The chloro ligands were eliminated as hydrochloric acid. The aluminum cores remained highly intact. Copyright © 2004 John Wiley & Sons, Ltd.     

Characterization of ARC/CL wheat flour, pork meat and skim milk powder reference materials for contents of toxic elements

Summary Wheat flour, pork meat and skim milk powder reference materials (RM) prepared and employed for the activities of the Sub-network on Trace Element Status in Food of the FAO European Cooperative Research Network on Trace Elements were subjected to an interlaboratory comparison study on the contents of Pb, Cd and Hg. The homogeneity of the above materials had earlier been shown to be within 2% for several essential elements and within 5 to 10% for Pb and Cd. An interlaboratory comparison study was conducted involving 17 reference laboratories recognized for their reliability and specialized in heavy metal determinations in biological materials. A total of seven methods based on four different analytical principles were employed to determine the contents of the above heavy metals. After the exclusion of outliers, the recommended concentration values expressed as the medians ±95% confidence limits were established. All of the recommended values reported here fell into category A, i.e. values recommended with a high degree of confidence according to the certification criteria established by Pszonicki. The present materials contain very low naturally occurring levels of all the heavy metals studied and have been successfully employed in the analytical quality control program of the above FAO study during the past five years.