Analysis of normal parameters of gastric chemism after pentagastrin stimulation, its diagnostic value in duodenal ulcer

The development of puberty, the sexual debut and the sexual function were investigated in a longitudinal study of an unselected material of 220 primary cases of hypospadiacs, treated during the period 1965 to 1969 and followed-up during the period 1965 to 1974. The development of puberty in hypospadiacs strongly resembled that in a normal male population. Out of 121 hypospadiacs between 13 and 30 years of age 66 had had sexual intercourse. The median age for the sexual debut was 16.9 years compared to 16.6 years in a normal male population. Thirty out of 55 hypospadiacs without experience of sexual intercourse were in the age-group 13-16. Hypospadiacs with experience of sexual intercourse continued their sexual function was normal. Forty-one out of 66 were married and 24 out of 41 had children. In order to study the influence of the surgical treatment on the sexual debut and sexual function the 121 hypospadiacs were divided into two groups: those in whom treatment was completed before or at the age of 12 years, and those in whom treatment was completed at 13 years of age or later. The median age for the sexual debut was 15.5 years in the former group and 17.6 in the later group. An interesting finding was that almost half of the hypospadiacs in whom treatment was complted at 13 years of age or later had had a preoperative sexual debut despite the presence of curvature in all cases, and despite the fact that all types of hypospadias were represented. The median age for the sexual debut in this group was 17.1 years.     

Human spinal arachnoid villi and granulations

A commercially available recording of Northwestern University Auditory Test No. 6 (N.U. No. 6) produced by Auditec of St. Louis was evaluated in a series of four studies. Interlist equivalence of this version was initially investigated, and then normative intelligibility functions were developed using listerners with normal hearing. Intelligibility functions for the original version of N.U. No. 6. prepared by Northwestern University, were then derived, concurrently with functions of the Auditec version, using (1) a group of listeners with normal hearing; and (2) a group with sensorineural hearing loss. The results demonstrated good interlist equivalence for the Auditec version of N.U. No. 6. The comparative intelligibility functions for the Auditec and Northwestern versions of N.U. No 6 furthermore indicated a difference between the two recordings, but it was concluded that for clinical purposes the two versions may be considered equivalent.     

Sequential interpolation functions

In the present paper it is shown how to achieve special interpolation functions that can be applied to the finite element method, least squares methods or other related numerical techniques. We call these functions sequential interpolation functions since one of the main characteristics of this technique refers to the fact that the refinement of the solution does not require the redefinition of the interpolation funtions used in a previous step, as the case for instance in the FEM. The present theory and the FEM using an isoparametric element were compared for a plane stress problem. The results show that both have the same degree of accuracy. The choice of the sequential interpolation functions is easier than those used in the finite element formulation and the computer time was reduced by about 50 per cent.     

Surface chemical heterogeneity of bacteriogenic iron oxides from a subterranean environment

This study quantifies the surface chemical heterogeneity of bacteriogenic iron oxides (BIOS) and its end-members (2-line ferrihydrite and intermixed intact and fragmented bacteria). On a dry weight basis, BIOS consisted of 64.5 +/- 1.8% ferrihydrite and 34.5 +/- 1.8% organic matter. Enrichment of Al, Cu, Cr, Mn, Sr, and Zn was shown in the solid versus the aqueous phase (1.9 < log Kd < 4.2). Within the solid-phase Al (69.5%), Cu (78.7%), and Zn (77.9%) were associated with the bacteria, whereas Cr (59.8%), Mn (99.8%), and Sr (79.4%) preferred ferrihydrite. Acid-base titration data from the BIOS and bacteria were fitted using FOCUS pKa spectroscopy. The bacteria spectrum with pKa's of 4.18 +/- 0.37, 4.80 +/- 0.54, 6.98 +/- 0.45, and 9.75 +/- 0.68 was similar to discrete and continuous spectra for intact and fragmented bacteria. The BIOS spectrum recorded pKa's of 4.27 +/- 0.51, 6.61 +/- 0.51, 7.89 +/- 1.10, and 9.65 +/- 0.66 and was deconvoluted to remove overlapping binding site contributions from the bacteria. The resulting residual iron oxide spectrum coincided with discrete MUSIC spectra for goethite and lepidocrocite with pKa values of 4.10 +/- 0.43, 6.53 +/- 0.45, 7.81 +/- 0.76, and 9.51 +/- 0.68. Surface site density analysis showed that acidic sites (pKa < 6) were contributed by the bacteria (37%), whereas neutral sites (6 < pKa < 8) were characteristic of the iron oxide fraction (35%). Basic sites (8 < pKa) were higher in the bacteria (57%), than in the BIOS (44%) or iron oxide fractions (47%). This analysis suggested a high degree of bacterial group masking and a similarity between the BIOS and goethite surface reactivity. An understanding of the BIOS surface chemical heterogeneity and inherent proton and metal binding capacity was obtained through the use of FOCUS apparent pKa spectroscopy.     

A Method for Patching Interleaving-Replay Attacks in Faulty Security Protocols

The verification of security protocols has attracted a lot of interest in the formal methods community, yielding two main verification approaches: i) state exploration, e.g. FDR [Gavin Lowe. Breaking and fixing the needham-schroeder public-key protocol using FDR. In TACAs'96: Proceedings of the Second International Workshop on Tools and Algorithms for Construction and Analysis of Systems, pages 147–166, London, UK, 1996. Springer-Verlag] and OFMC [A.D. Basin, S. Mödersheim, and L. Viganò. An on-the-fly model-checker for security protocol analysis. In D. Gollmann and E. Snekkenes, editors, ESORICS'03: 8th European Symposium on Research in Computer Security, number 2808 in Lecture Notes in Computer Science, pages 253–270, Gjøvik, Norway, 2003. Springer-Verlag]; and ii) theorem proving, e.g. the Isabelle inductive method [Lawrence C. Paulson. The inductive approach to verifying cryptographic protocols. Journal in Computer Security, 6(1-2):85–128, 1998] and Coral [G. Steel, A. Bundy, and M. Maidl. Attacking the asokan-ginzboorg protocol for key distribution in an ad-hoc bluetooth network using coral. In H. König, M. Heiner, and A. Wolisz, editors, IFIP TC6 /WG 6.1: Proceedings of 23rd IFIP International Conference on Formal Techniques for Networked and Distributed Systems, volume 2767, pages 1–10, Berlin, Germany, 2003. FORTE 2003 (work in progress papers)]. Complementing formal methods, Abadi and Needham's principles aim to guide the design of security protocols in order to make them simple and, hopefully, correct [M. Abadi and R. Needham. Prudent engineering practice for cryptographic protocols. IEEE Transactions on Software Engineering, 22(1):6–15, 1996]. We are interested in a problem related to verification but far less explored: the correction of faulty security protocols. Experience has shown that the analysis of counterexamples or failed proof attempts often holds the key to the completion of proofs and for the correction of a faulty model. In this paper, we introduce a method for patching faulty security protocols that are susceptible to an interleaving-replay attack. Our method makes use of Abadi and Needham's principles for the prudent engineering practice for cryptographic protocols in order to guide the location of the fault in a protocol as well as the proposition of candidate patches. We have run a test on our method with encouraging results. The test set includes 21 faulty security protocols borrowed from the Clark-Jacob library [J. Clark and J. Jacob. A survey of authentication protocol literature: Version 1.0. Technical report, Department of Computer Science, University of York, November 1997. A complete specification of the Clark-Jacob library in CAPSL is available at http://www.cs.sri.com/millen/capsl/].     

Particle-Swarm Optimization in Antenna Design: Optimization of Log-Periodic Dipole Arrays

This paper presents a short tutorial and overview of optimization algorithms based on particle-swarm schemes, and their application to solving electromagnetic problems. As a practical example, a particle-swarm optimization (PSO) tool has been applied in conjunction with the Numerical Electromagnetics Code (NEC) to get the design curves of optimized log-periodic dipole arrays (LPDAs). The graphs show the performance of several radiation parameters (directive gain, front-to-back ratio, bandwidth, SWR, and half-power beamwidth in the E and H planes) as a function of typical design parameters of log-periodic dipole arrays (geometrical parameters and characteristics of the feed). Examples of optimized antennas are given, and their performance is compared to that of standard log-periodic dipole arrays.     

Mapping and monitoring riparian vegetation distribution,structure and composition with regression tree models and post-classification change metrics

Riparian systems have become increasingly susceptible to both natural and human disturbances as cumulative pressures from changing land use and climate alter the hydrological regimes. This article introduces a landscape dynamics monitoring protocol that incorporates riparian structural classes into the land-cover classification scheme and examines riparian change within the context of surrounding land-cover change. We tested whether Landsat Thematic Mapper (TM) imagery could be used to document a riparian tree die-off through the classification of multi-date Landsat images using classification and regression tree (CART) models trained with physiognomic vegetation data. We developed a post-classification change map and used patch metrics to examine the magnitude and trajectories of riparian class change relative to mapped disturbance parameters. Results show that catchments where riparian change occurred can be identified from land-cover change maps; however, the main change resulting from the die-off disturbance was compositional rather than structural, making accurate post-classification change detection difficult.     

Comparison of data gap-filling methods for Landsat ETM+ SLC-off imagery for monitoring forest degradation in a semi-deciduous tropical forest in Mexico

A number of methods to overcome the 2003 failure of the Landsat 7 Enhanced Thematic Mapper (ETM+) scan-line corrector (SLC) are compared in this article in a forest-monitoring application in the Yucatan Peninsula, Mexico. The objective of this comparison is to determine the best approach to accomplish SLC-off image gap-filling for the particular landscape in this region, and thereby provide continuity in the Landsat data sensor archive for forest-monitoring purposes. Four methods were tested: (1) local linear histogram matching (LLHM); (2) neighbourhood similar pixel interpolator (NSPI); (3) geostatistical neighbourhood similar pixel interpolator (GNSPI); and (4) weighted linear regression (WLR). All methods generated reasonable SLC-off gap-filling data that were visually consistent and could be employed in subsequent digital image analysis. Overall accuracy, kappa coefficients (κ), and quantity and allocation disagreement indices were used to evaluate unsupervised Iterative Self-Organizing Data Analysis (ISODATA) land-cover classification maps. In addition, Pearson correlation coefficients (r) and root mean squares of the error (RMSEs) were employed for estimates agreement with fractional land cover. The best results visually (overall accuracy > 85%, κ < 9%, quantity disagreement index < 5.5%, and allocation disagreement index < 12.5%) and statistically (r > 0.84 and RMSE < 7%) were obtained from the GNSPI method. These results suggest that the GNSPI method is suitable for routine use in reconstructing the imagery stack of Landsat ETM+ SLC-off gap-filled data for use in forest-monitoring applications in this type of heterogeneous landscape.     

SAR detection and characterization of sea surface slicks

In this paper we demonstrate SAR system capability for detecting and characterizing marine surface slicks. During an aircraft measurement campaign over the Gulf of Genoa (Italy), a multi-frequency SAR system, operating in P-, L- and C-bands, explored a sea area heavily covered by slicks. At the same time in situ measurements were performed with an interferential microwave probe, installed on board a small boat, capable of measuring high resolution sea spectra up to frequencies of capillary waves. By plotting SAR pixel intensity versus sea wave Bragg frequency we obtained wide portions of the sea spectrum region affected by the surface film damping. Spectra derived from SAR imagery and from gauge data present comparable slopes and furthermore the ratio between clean to slicked water spectrum obtained with the two techniques were surprisingly similar. This demonstrates the multi-frequency SAR systems ability to detect and characterize sea surface films assuming the Bragg mechanism in the radar backscatter. The outlined analysis suggests a simple methodology to monitor coastal water quality by using airborne SAR.