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One potential source of folkbiological knowledge loss is changing patterns of interaction with the natural world stemming from ''modernizing'' material change. This article compares models of plant knowledge among age-matched groups of children and adults in two communities of a municipality located in the highlands of Chiapas, Mexico. Use of the Cultural Consensus Model (CCM), analysis of residual agreement, and examination of model content show that while plant knowledge remains fairly robust in the municipality, devolutionary change is ongoing and manifests in the urbanized municipal town center relative to a rural outlying hamlet. Quantifying disparities in folkbiological knowledge is considered as a preliminary step in understanding general processes of culture change. Recent investigations into domain-specific folkbiological expertise in adults and the acquisition of folkbiological models in children shows that differences in propositional knowledge interact with culture-specific reasoning strategies and have profound consequences for value complexes and environmental behavior. (knowl- edge devolution, child development, culture change, folkbotany, Tzotzil Maya)

This paper presents a parameter space approach to constrained variance and minimum variance PID controller design for LTI models. The technique is based on rational transfer functions of the plant and noise models. Loci corresponding to a fixed variance can be mapped into parameter planes for PID and PI type controllers to graphically display regions which satisfy the constraint, thereby guiding a design to appropriate controller gains. Requirements for tracking regulation can be readily achieved without excessively increasing the output variance. The usual advantages of parameter space techniques apply where other design criteria may be superimposed, allowing multiple objectives to be achieved non-conservatively. The superposition of the parameter space boundaries from existing robust control techniques thus allows non-conservative robust minimum variance PID design. A design example compares the technique to an algebraic minimum variance design using an integrator when tracking is required.

This work involves a study on laser ignition (LI) in an internal combustion (IC) engine and investigates the effects on control of engine combustion performance and stability of varying specific laser parameters (beam energy, beam quality, minimum beam waist size, focal point volume and focal length). A Q-switched Nd?:?YAG laser operating at the fundamental wavelength 1064?nm was successfully used to ignite homogeneous stoichiometric gasoline and air mixtures in one cylinder of a 1.6?litre IC test engine, where the remaining three cylinders used conventional electrical spark ignition (SI). A direct comparison between LI and conventional SI is presented in terms of changes in coefficient of variability in indicated mean effective pressure (COVIMEP) and the variance in the peak cylinder pressure position (VarPPP). The laser was individually operated in three different modes by changing the diameter of the cavity aperture, where the results show that for specific parameters, LI performed better than SI in terms of combustion performance and stability. Minimum ignition energies for misfire free combustion ranging from 4 to 28?mJ were obtained for various optical and laser configurations and were compared with the equivalent minimum optical breakdown energies in air.

A technique based on Horowitz’s nonlinear quantitative feedback theory is presented, in which the size of the uncertainty is reduced by cancellation of the plant nonlinearity through nonlinear inverse compensation. Linear identification of the open loop nonlinear inverse compensated plant is used to obtain an unstructured uncertainty representation, however, rather than computing QFT templates based on parametric uncertainty. An increase in achievable robust performance with any linear robust performance control design technique may then be obtained. The method is experimentally validated by application to a SISO automotive SI engine idle speed control problem using an electric dynamometer.

This paper presents a non-linear inverse compensation methodology based on a technique similar to Horowitz's non-linear quantitative feedback theory. A causal inverse is found based on an identified non-linear plant model. Linear identification of the non-linear identified inverse compensated system is carried out in order to achieve a reduction in the unstructured uncertainty representation. Subsequent robust control design results in an improvement in robust stability and robust performance over the uncompensated system. Using a parameter space linear robust control design technique, the method is applied to the automotive Spark ignition (SI) engine idle speed control problem and is experimentally validated using an electric dynamometer.

Treating non-linear systems as equivalent time-invariant systems with associated uncertainty is often excessively conservative and significantly reduces the achievable robust performance. This paper presents a method for reducing the associated uncertainty of non-linear uncertain single-input single-output systems based on Horowitz's method for non-linear quantitative feedback theory. The new method implements a non-linear compensator based on an approximate causal inversion of an identified nominal model. The inverse system compensator reduces the uncertainty associated with the linear time-invariant equivalent system. The method is applied and experimentally validated on the idle speed dynamics of an automotive SI engine system using an electric dynamometer.

An approach for tuning PID-type controllers is developed for single input single-output, linear time-invariant systems, based on an extension to the method of D-partition. This method permits design for simultaneous minimum gain and phase margin requirements. It also allows design for specified maximum gain and phase cross-over frequencies of the controlled system. The technique can be applied to systems with stable or unstable plants as well as to irrational systems with significant time delay. Another advantage of the method is that it can be used for various controller configurations including derivative in the feedback path. Three examples illustrate the tuning method.

Twenty-seven Wagyu-sired steers were fed for 90 (14 steers) or 170 (13 steers) days to study the effects of time on feed on palatability and fatty acid composition, and the effects of post-mortem aging time (2, 4 or 10 days) on palatability. Hot carcass weight, fat thickness, longissimus dorsi muscle area, yield grade, estimated kidney, pelvic and heart fat and maturity score were increased (p0.05) by an additional 80 days on the high concentrate feed, but marbling was not changed (p0.05). Feeding the high concentrate diet for 170 days increased Warner-Bratzler shear force values (p0.05) and tended to decrease tenderness (p0.05), flavor intensity and connective tissue scores. For the 90 day feeding group, 4 days of aging improved connective tissue score (p0.05) and tended to increase (p0.05) tenderness scores and decrease shear force, compared with 2 days of aging. For the 170 day feeding group, 10 days of aging improved (p0.05) shear force and all sensory attributes except flavor intensity, compared to 2 days of aging. An additional 80 days on feed decreased (p0.05) stearic acid and total saturated fatty acids (SFA) and generally increased (p0.05) monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), MUFA:SFA, and PUFA:SFA in subcutaneous fat and longissimus dorsi muscle. The cholesterol content of fat and muscle increased (p0.05) as time on feed increased. Ninety days on a high concentrate diet was adequate for yearling crossbred Wagyu steers to produce highly acceptable carcasses. The additional 80 days on feed produced little or no overall benefit and the steers became overfinished and less tender. Ten days post-mortem aging improved (p0.05) all palatability attributes except flavor intensity.

A graphical technique for tuning PID-type controllers based on the method of D-partition is proposed for single-input-single-output linear time invariant systems. The tuning method shifts all the roots of the characteristic equation of the controlled system to a certain desirable region in the left half of the complex plane (LHP) to achieve a specified least absolute and least relative stability margin. The method can be used to tune a precompensator, in a two degree of freedom structure, so as to improve tracking behaviour. The method can be used for both stable and unstable systems, for systems with significant time delay and for various controller configurations, including derivative in the feedback path.

This paper presents an approach for finding regions Of specified gain margins (GM) and phase margins (PM) in the parameter space of a single-input single-output (SISO) control system with adjustable parameters. The method uses the Nyquist stability criterion of encirclement of a point in the polar plot. The necessary boundaries of the specified GM or PM regions in the parameter space are fully treated by mapping a point related to specified GM or PM in the polar plane into the parameter space. A general problem with previous mapping techniques is identified where points in the parameter space do not necessarily satisfy the required GM or PM. A searchbased technique is proposed to address this problem. Three examples illustrate the theoretical development. I. Introduction G AIN margin (GM) and phase margin (PM) are perhaps the two most important and widespread accepted criteria in analysis and design of practical control systems. These criteria are related to the open-loop transfer function of systems. In the robust stabilization problem of control systems, however, parameter space methods generally consider the closed-loop characteristic equation of the system.1"3 Parameter space techniques were initially studied by Vishnegradesky for a third-order system using a graphical technique that was popularized by Nimark and was referred to as D-partition or D-decomposition4"6 in its early development. This method actually establishes a direct correlation between the variable parameters of the closed-loop characteristic equation and the various important stability regions, e.g., open left half of the complex plane (OLHP). The method is directly suitable for graphical representation, in which case it is convenient to consider two parameters at a time. The idea of correlating the free parameters of the open-loop transfer function of a system and the relative stability regions appears to have been initially given in Ref. 7. Unfortunately , the method was not developed in detail, and the idea of isolating the GM region in the parameter plane was not correct. A recent improvement to the idea was presented by introducing the gain-phase margin tester into the system,8 which attempted to isolate specified GM and PM regions in the parameter space to allow a choice of the adjustable parameters. However, it is argued here that in this latter approach all the possible boundaries of the relative stability regions are not in fact considered, and some and possibly all points in the relative stability region do not necessarily satisfy the actual specified relative stability margin. In particular, the so called "singular boundaries" of the D-partition method6 need to be considered. Finally, boundaries arising through frequency loci with re-entrant or convoluted characteristics also need to be considered with care. In this paper, a method for accounting for the

A novel λ -normalised air-fuel ratio (AFR)estimator for port-fuel injected (PFI) spark-ignition (SI) internal combustion (IC) engines is proposed. The estimator has an algebraic NARMAX structure which is developed by identification from dynamometer based engine test data. The estimated λ signal has significantly less time delay than the measured λ signal. A slow acting PID trimming loop is implemented to remove long time-scale drift between estimated and measured λ. Two robust linear controllers are designed each to provide a 2 x 2 MIMO feedback system to regulate λ and to allow tracking of torque demand. Both a mixed-sensitivity (MS) maximum singular value H∞ controller and a MS Frobenius norm H∞ controller are implemented and evaluated experimentally. The Frobenius norm H∞ controller, allows the use of an intuitive Hadamard element-by-element weighting selection. This is implemented to decouple the torque and AFR paths. Both controllers are otherwise found experimentally to have similar robustness and performance, but the Frobenius norm H∞ controller achieves a superior decoupling.

This paper presents a nonparametric approach to the design of feedback for stable invertible MIMO plants using Frobenius norm H∞, Hadamard weighted feedback control for mixed-sensitivity criterea. It is shown that the corresponding mixed sensitivity performance function may be reduced to one of quasi-circular type, appropriate for using Nehari-solution algorithms to achieve good solution-convergence by disk iteration. A non-parametric interpolation scheme is developed to retain the quasi-circular function and to guarantee internal stability. The disk-iteration method of Helton-Merino for analytic function optimisation may then be applied to optimise the mixed sensitivity criterion subject to the required internal stability constraints. The complete design process is thus based entirely on the plant frequency response. A simulation study of a 2 × 2 MIMO automotive IC engine torque and fuelling controller is given which compares the Frobenius norm H∞ method with a maximum singular norm H∞ controller . It is shown that the Frobenius norm method gives direct control over disturbance decoupling but otherwise enjoys similar robustness and performance to the maximum singular norm controller. The approach thus presents a nonparametric alternative to the state-space Frobenius norm methods of Van Diggelen and Glover.

Continuous chromatographic separator techniques have allowed the extraction of more simple sugars from molasses (MOL). The resultant byproduct, concentrated separator byproduct (CSB), has reduced readily fermentable carbohydrates but elevated CP and mineral content. The feed value of CSB was compared to that of MOL in two separate trials. In Trial 1, a chopped forage mixture containing 84% meadow grass hay and 8% alfalfa hay was mixed with either CSB or MOL at 7.3% of DM. Diets were administered to four ruminally cannulated cows in a single reversal design. digestibility of DM, ADF, NDF, and CP were measured. Ruminal pH, ammonia nitrogen (NH3), VFA, total viable bacteria (TVB), cellulose-xylan fermenting bacteria (CXFB), and ciliated protozoa (PTZ) were evaluated. Blood profiles of electrolytes were also measured. Digestibility of DM, ADF, NDF, and CP were 69.03, 68.58; 57.48, 57.77; 65.62, 64.75; and 67.63, 65.07% for the MOL and CSB diets, respectively. Only CP digestibility differed (P less than .02). Ruminal pH, NH3, VFA, TVB, CXFB, and PTZ were 6.97, 6.93; 14.21, 16.71 mg/dL; 74.30, 74.78 mumol/mL; 26.79, 27.36 x 10(9)/mL; 21.72, 21.36%; and 13.90, 7.80 x 10(3)/mL for the MOL and CSB diets, respectively. Ruminal measurements did not differ. Blood electrolyte profiles were not altered. Trial 2 was similar to Trial 1 except the basal diet used was 47% barley grain, 35% alfalfa hay, and 10% barley straw. Either MOL or CSB was added at 7.3% of the DM. Digestibilities of DM, ADF, NDF, and CP were 69.52, 71.33; 35.96, 37.11; 27.93, 33.47; and 71.10, 73.66% for the MOL and CSB diets, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

This paper describes a neural-network (NN)-based scheme for the control of a cylinder peak pressure position (PPP)—also known as the location of peak pressure (LPP)—by spark timing in a gasoline internal combustion engine. The scheme uses the ionization current to act as a virtual sensor, which is subsequently used for PPP control. A NN is trained offline on principal-component analysis data to predict the cylinder peak pressure position under dynamically varying engine load, speed, and spark advance (SA) settings. Experimental results demonstrate that the PPP prediction by the NN correlates well with those measured from in-cylinder pressure sensors across transients of load, SA, and engine speeds. The dynamic training data allow rapid model identification across the identified engine range, as opposed to just fixed operating points. A linear robust constrained-variance controller, which is a robustified form of the minimum variance controller, is used to regulate the PPP by SA control action, using the NN as a PPP sensor. The control scheme is validated by experimental implementation on a port fuel-injected four-cylinder 1.6 l gasoline internal combustion engine.

We report data from 31 subjects with focal hemisphere lesions (15 left hemisphere) as well as 16 normal controls on a battery of tasks assessing the estimation, production and reproduction of time intervals ranging from 2–12 seconds. Both visual and auditory stimuli were employed for the estimation and production tasks. First, ANOVAs were performed to assess the effect of stimulus modality on estimation and production tasks; a significant effect of stimulus modality was observed for the production but not the estimation task. Second, accuracy was significantly different for the 2 second interval as compared to longer intervals. Subsequent analyses of the data from 4–12 second stimuli demonstrated that patients with brain lesions were more variable than controls on the estimation and reproduction tasks. Additionally, patients with brain lesions but not controls exhibited significant differences in performance on the different tasks; patients with brain lesions under-produced but over-estimated time intervals of 4–12 seconds but performed relatively well on the reproduction task, a pattern of performance consistent with a “fast clock”. There was a significant correlation between impaired performance and lesions of the parietal lobe but there was no effect of laterality of lesion or correlation between lateral frontal lobe lesions and impairment on any task.

Population-based data from 10 centres in Burma, Thailand, China and Vietnam, have been analysed to assess those social and environmental factors which may be associated with pre-term delivery and low birth-weight. The philosophy behind the study was that if the same association was found in different countries, then the association may be causal; if associations differed in the various countries, then causality was unlikely. The major findings were as follows: a strong association between low birth-weight and pre-term delivery and the unmarried state (RR 1.64, 1.39), a consistent reduced risk of pre-term delivery when the father was in a managerial post (RR 0.77), an excess risk of pre-term delivery if the mother was a housewife (RR 1.16), lifting heavy objects at the time of quickening (RR 1.63) or frequently bending and stooping at the time of quickening (1.15). Strong associations were found with both paternal and maternal education levels but these were strongest for the mother's education level. The association was far stronger for pre-term delivery than for low birth-weight and it is assumed that the low birth-weight effect is secondary to pre-term delivery. The only variation with maternal age concerned an excess of low birth-weight among teenage mothers, but not of pre-term delivery, and an excess of low birth-weight but not pre-term delivery among mothers with small head circumferences or small arm circumferences. We conclude that the aetiology of growth retardation and pre-term delivery are probably different in South-east Asia, and point out the need to elucidate further the strong variation with education level.

We report a 53-year-old patient (AWF) who has an acquired deficit of audiovisual speech integration, characterized by a perceived temporal mismatch between speech sounds and the sight of moving lips. AWF was less accurate on an auditory digit span task with vision of a speaker's face as compared to a condition in which no visual information from the lower face was available. He was slower in matching words to pictures when he saw congruent lip movements compared to no lip movements or non-speech lip movements. Unlike normal controls, he showed no McGurk effect. We propose that multisensory binding of audiovisual language cues can be selectively disrupted.

Previous studies have demonstrated that both visual and proprioceptive feedback influence motor control. The relative contributions of these sensory modalities to the on-line computation of body position—that is, the body schema—remain unclear. We report a study designed to explore the roles of vision and proprioception in motor planning. The task required subjects to judge if a pictured stimulus was a right or left hand; stimuli included pictures of a right or left hand in a palm up or palm down position and in six different angular rotations (0 ◦ ,6 0 ◦ , 120 ◦ , 180 ◦ , 240 ◦ , 300 ◦ ). Each subject was tested with his/her right hand palm down and palm up. There were three conditions: a “control” condition (real hand in view), a “fake hand” condition (fake hand in view, real hand out of view), and a “proprioception” condition (no fake hand, real hand out of view). We found that proprioceptive input (that is, the subject’s “felt position”) had a significant influence on mental rotation whereas the visually perceived posture of the hand did not. We suggest that, at least under some circumstances, proprioceptive inflow may represent the dominant sensory input to the on-line representation of the body in space. © 2004 Elsevier Ireland Ltd. All rights reserved.

Integrating sensory information across modalities is necessary for a cohesive experience of the world; disrupting the ability to bind the multisensory stimuli arising from an event leads to a disjointed and confusing percept. We previously reported (Hamilton et al., 2006) a patient, AWF, who suffered an acute neural incident after which he displayed a distinct inability to integrate auditory and visual speech information. While our prior experiments involving AWF suggested that he had a deficit of audiovisual speech processing, they did not explore the hypothesis that his deficits in audiovisual integration are restricted to speech. In order to test this notion, we conducted a series of experiments aimed at testing AWF’s ability to integrate cross-modal information from both speech and non-speech events. AWF was tasked with making temporal order judgments (TOJs) for videos of object noises (such as hands clapping) or speech, wherein the onsets of auditory and visual information were manipulated. Results from the experiments show that while AWF performed worse than controls in his ability to accurately judge even the most salient onset differences for speech videos, he did not differ significantly from controls in his ability to make TOJs for the object videos. These results illustrate the possibility of disruption of intermodal binding for audiovisual speech events with spared binding for real-world, non-speech events.

Various types of optical fibres have been investigated and compared for delivering high power laser beams to an optical plug (comprising of lenses and an optical window) for the application of laser-induced ignition of gasoline and air mixtures in an automotive internal combustion engine. Three main types of optical fibre were examined: multi-mode step index silica, sapphire and photonic crystal. The fibres had various core sizes ranging from 35 to 600 μ ma nd numerical apertures between 0.046 and 0.64. A Q-switched Nd:YAG laser operating at the fundamental wavelength 1064 nm with a pulse length of 15 ns was used for the testing. Fibre output beam properties, including beam mode quality, output divergence, transmission losses, beam energy thresholds and effects of engine vibration were investigated. These fibre beam properties were compared with known beam parameters for laser ignition to assess the suitability of such fibres for a laser ignition system. Online fibre delivery laser ignition engine tests were performed with the most suitable fibres, which showed that combustion could be achieved with this system despite a relatively large percentage of misfires.

Singular perturbation methods are used to provide a basis for the analysis of the asymptotic controllability of multivariable linear systems containing small ‘ parasitic ’ elements, and for the design of feedback controllers which will effect asymptotic eigenvalue assignment in such systems.

Socioeconomic factors relating to all maternal deaths identified during the 12 months of the Jamaican Perinatal Morbidity and Mortality Survey were compared with a control population of over 10,000 women. The maternal mortality rate was 11.5 per 10,000 livebirths. Initial analyses revealed (a) that the risk of maternal death declined with increasing maternal education level, (b) that mothers who lived in households with direct pumped water and/or flush toilets enjoyed a reduced risk; (c) mothers who were themselves the major wage earner and (d) those living in households where the major wage earner and source of income was an agricultural worker or farmer were at increased risk of maternal death. A previous analysis showed that the mother's age, her parity and variables indicating access to medical care were important. Logistic regression showed that only maternal age and toilet facilities were independently associated with maternal mortality.

Prospectively gathered data from eight geographically defined areas in south-east Asia included serial measures of blood pressure, proteinuria and oedema during pregnancy. A total of 15,476 pregnancies were included. Both antenatal oedema and proteinuria were markers of increased risk of antenatal diastolic hypertension, proteinuric pre-eclampsia and eclampsia. However they identified fetuses at high risk of low birthweight and perinatal mortality only in areas where the incidence of hypertension was low. As a screening strategy to identify women who are at increased risk of antenatal diastolic hypertension, of proteinuric pre-eclampsia and of eclampsia, the most efficient strategy is probably to use the presence of oedema and/or proteinuria. The sensitivity of using this method for identifying women with proteinuric pre-eclampsia is high, but for identifying eclampsia it is still relatively low. Where resources are available there is probably no substitute for using a sphygmomanometer and measuring blood pressure.

Singular perturbation methods are used to demonstrate that the transfer function matrices of multivariable linear systems containing small ‘parasitic’ elements have a distinctive structure which can be exploited in the design of controllers fur systems of this class by the application of frequency-domain methods.

Explicit forms for the transmission operators for a wide class of linear systems subject to control by a class of feedback filter indicate that design may be made on the basis of separate subsystems in the manner associated with state-estimating controllers but realized by an output feedback compensator configuration without input sensing. The results show that an account must be taken of the joint influence that the properties of these separately designed subsystems have on the resulting basic closed-loop transmission operators and indicate directly how the choice of design parameters governs the complete structure of these operators.

The “alternation” in m.p. in homologous series is discussed. In particular four series of derivatives of methyl n-alkylketones are studied and the “alternations” shown diagrammatically.

The care of asthmatic children is commonly sub-optimal. Accordingly the costs and benefits of sending a district health authority community nurse, who had specific training in asthma management, into the homes of 43 families with asthmatic children were assessed. During the six months the asthma nurse visited these homes, the children developed and sustained, higher peak expiratory flow rates than 43 control asthmatics. The direct costs of the asthma nurse was 15 pounds/patient/six months.

Les methodes de quatre laboratoires sont decrites et composees dans le cadre de la mise en place d'une organisation interlaboratoire

STUDY OBJECTIVE: The objective was to test the hypothesis that easy access to sophisticated hospitals is associated with a reduction in perinatal mortality. DESIGN: The study was a nationwide questionnaire survey of a birth cohort. SUBJECTS: All deliveries greater than 500g weight of singleton live births and stillbirths occurring throughout Greece during April 1983 were included. Completed questionnaires were returned for 10,953 deliveries (8% of total annual registered births in Greece), and data on 10,790 singleton births were analysed, including 127 stillbirths and 137 early neonatal deaths. MEASUREMENTS AND MAIN RESULTS: The questionnaires contained information on demographic characteristics of each parent, mother's reproductive history, and clinical course of pregnancy, labour and perinatal period. Mothers living in big urban centres were compared with the rest of the country. Overall mortality rates were similar but births in the big urban centres were of significantly lower weight due to fetal growth retardation. Logistic regression analysis, taking account of birthweight, parity, maternal age, and maternal education showed that there was an advantage to mothers living in big urban centres, perinatal mortality being 63% higher in the rest of the country (chi 2 = 7.4, p less than 0.01). CONCLUSION: The evidence obtained supports the original hypothesis and suggest that a reduction in the high perinatal mortality rate in Greece may be achieved by restructuring the perinatal services.