This paper presents an analysis of the Ziegler-Nichols frequency response method for tuning PI controllers, showing that this method has severe limitations. The limitations can be overcome by a simple modification for processes where the time delay is not too short. By a major modification it is possible to obtain new tuning rules that also cover processes that are lag dominated.

Background: We were concerned that a fixed rather than a weight-based dosing regimen of dalteparin sodium to prevent venous thromboembolism. (VTE) might result in decreased efficacy in obese patients and decreased safety in elderly patients. Methods: We retrospectively performed subgroup analyses using the database from the Prospective Evaluation of Dalteparin Efficacy for Prevention of VTE in Imm

Mammalian leukotriene A4 (LTA4) hydrolase is a bifunctional zinc metalloenzyme possessing an Arg/Ala aminopeptidase and an epoxide hydrolase activity, which converts LTA4 into the chemoattractant LTB4. We have previously cloned an LTA4 hydrolase from Saccharomyces cerevisiae with a primitive epoxide hydrolase activity and a Leu aminopeptidase activity, which is stimulated by LTA4. Here we used a m

Phosphine derivatives of alkylidyne tricobalt carbonyl clusters have been tested as catalysts/catalyst precursors in intermolecular and (asymmetric) intramolecular Pauson-Khand reactions. A number of new phosphine derivatives of the tricobalt alkylidyne clusters [Co(3)(mu(3)-CR)(CO)(9)] (R = H, CO(2)Et) were prepared and characterised. The clusters [Co(3)(mu(3)-CR)(CO)(9-x)(PR'(3))(x)] (PR'(3) = a

This is a study on the recovery and recycling of copolymer in aqueous two-phase systems containing random copolymers of ethylene oxide (EO) and propylene oxide (PO). The random copolymers separate from water solution when heated above the lower critical solution temperature (LCST). The primary phase systems were composed of EOPO copolymer and hydroxypropyl or hydroxyethyl starch. After phase separ

This paper describes the development of a prototype product named MAGIC-HAND that has been developed to open bottles, jars and packages that require a twisting action. Its intended users are people with severe disabilities, who are not capable of using the current range of package opening tools. MAGIC-HAND is a kitchen accessory device that fits into standard kitchen furniture. The machine uses no

We describe a simple radioimmunoassay of beta-microseminoprotein, one of the three most abundant secretory proteins of the prostate gland. The detection limit of the assay is 1 microgram/L, and its precision, expressed as the total coefficient of variation, is less than 10% for values between 10 and 150 micrograms/L. Using this assay, we found that beta-microseminoprotein immunoreactivity was pres

Changes in soil texture, bulk density, pH, concentrations and stocks of OC, N, P and K before and after conversion of a 6-year-old Acacia senegal plantation to other land management systems (LMS) were investigated, after three cropping seasons, in the drylands of western Sudan. LMS included pure and intercropped sorghum (PS), roselle (PR) and grasses (PC) with A. senegal at high and low-tree densi

in this paper, we introduce two new methods for solving binary quadratic problems. While spectral relaxation methods have been the workhorse subroutine for a wide variety of computer vision problems-segmentation, clustering, subgraph matching to name a few-it has recently been challenged by semidefinite programming (SDP) relaxations. In fact, it can be shown that SDP relaxations produce better low

Maternally derived androgens have been shown to influence offspring phenotype in various ways. In birds, the benefits of prenatal androgen exposure, such as increased competitiveness and accelerated growth in nestlings, have been suggested to be balanced by costs, such as reduced immune function. In this study, we used an integrative approach to examine the influence of yolk androgens on the devel

Objective: We examined pituitary tumor volumes in patients treated with pegvisomant for 18 months or longer and in whom the tumors were monitored for at least 3 years. We present details on 9 of 304 patients in clinical trials with pegvisomant who experienced tumor growth within the first year of treatment. Method: Magnetic reonance images prior to start of pegvisomant and at last follow-up were e

The admission control mechanism is an important part of many communication systems. In this paper we investigate load control mechanisms for server systems, that is systems that may be modelled as queueing systems. We show how control theory can be used when designing controllers for a G/G/1-system. We design a PI-controller for the system and compare the steady-state and transient behavior of thi

Background: Gallstone ileus is associated with high morbidity and mortality rates. Enterolithotomy as a single procedure is recommended to minimize complications. The trauma could potentially be reduced further by using a laparoscopic technique. Methods: Thirty-two consecutive patients with gallstone ileus operated by a laparoscopic or open approach between 1992 and 2004 were studied retrospective

The paper addresses a certain nonlocal plasticity model, where the consistency condition may be rewritten from a Fredholm equation of the second kind into a second order differential equation. Hereby, a case of equivalence between a nonlocal model and a gradient model will be found. (C) 2008 Elsevier Ltd. All rights reserved.

Degradation of the dry semiarid ecosystems in the Mu Us Sandy Land of north central China was explored using high-resolution satellite images from 1978, 1987 and 1996. This study monitored both changes in grassland biomass production and reclamation activities to detect the nature and scale of land degradation since major economic reforms were introduced in 1978. The position of the high-resolutio

The timing of reproduction in birds varies considerably within populations and is often under strong natural selection. Individual timing within years is dependent on a range of environmental factors in addition to having an additive genetic basis. In vertebrates, an increasing amount is known about the molecular basis for variation in biological timing. The Clock gene includes a variable poly-glu