1,212 research outputs found
MIMO nonlinear PID predictive controller
A class of nonlinear generalised predictive controllers (NGPC) is derived for multi-input multi-output (MIMO) nonlinear systems with offset or steady-state response error. The MIMO composite controller consists of an optimal NGPC and a nonlinear disturbance observer. The design of the nonlinear disturbance observer to estimate the offset is particularly simple, as is the associated proof of overall nonlinear closed-loop system stability. Moreover, the transient error response of the disturbance observer can be arbitrarily specified by simple design parameters. Very satisfactory performance of the proposed MIMO nonlinear predictive controller is demonstrated for a three-link nonlinear robotic manipulator example
Does a Carbonatite Deposit Influence Its Surrounding Ecosystem?
Carbonatites are unusual alkaline rocks with diverse compositions. Although previous work has characterized the effects these rocks have on soils and plants, little is known about their impacts on local ecosystems. Using a deposit within the Great LakesâSt. Lawrence forest in northern Ontario, Canada, we investigated the effect of a carbonatite on soil chemistry and on the structure of plant and soil microbial communities. This was done using a vegetation survey conducted above and around the deposit, with corresponding soil samples collected for determining soil nutrient composition and for assessing microbial community structure using 16S/ITS Illumina Mi-Seq sequencing. In some soils above the deposit a soil chemical signature of the carbonatite was found, with the most important effect being an increase in soil pH compared with the non-deposit soils. Both plants and microorganisms responded to the altered soil chemistry: the plant communities present in carbonatite-impacted soils were dominated by ruderal species, and although differences in microbial communities across the surveyed areas were not obvious, the abundances of specific bacteria and fungi were reduced in response to the carbonatite. Overall, the deposit seems to have created microenvironments of relatively basic soil in an otherwise acidic forest soil. This study demonstrates for the first time how carbonatites can alter ecosystems in situ
Studies on Pre-slaughter Handling of Pigs and its Relationship to Meat Quality
End of Project ReportsTwo quality defects of pork which are affected by preslaughter
handling are PSE (Pale Soft Exudative) and DFD (Dark
Firm Dry) meat.
The incidence of PSE pork is mainly a function of the breed of
pig but short-term stressful handling before slaughter and feeding
too close to slaughter are also involved. DFD meat is a result of
prolonged stressful handling. PSE meat is pale and uneven in
colour and exudes fluid making it unattractive in the retail display
while dark meat appears stale and is prone to bacterial spoilage.
After slaughter muscle metabolism continues and muscle glycogen
is converted to lactic acid reducing meat pH. Prolonged stress
results in glycogen depletion, pre-slaughter feeding results in
elevated levels. Colour may be assessed subjectively by eye or
objectively by a meter colour but pH of the meat is closely related
to colour and measurement of pH at 45 minutes post-slaughter is
frequently used to predict ultimate colour and pH.
The objective of this study was to examine pre-slaughter handling
practices and their relationship with meat quality (pH, colour).
In the first trial, a survey of the amounts of stomach contents in
pigs at slaughter in two factories found similar amounts to
comparable surveys in France and the UK. It was concluded that
most pigs had been fasted for an adequate time before delivery.
The relationship between the amount of stomach contents and
meat quality in this survey was poor.
In the second trial, pigs from the Moorepark herd fed by either a
computerised wet feeding system or an ad libitum dry feed system
were slaughtered after overnight fasting or with feed available up
to loading for transport to the factory, two to three hours before
slaughter. There was no difference between feeding systems in
meat colour or pH but fasted pigs, on both feeding systems, had
darker meat and meat of a higher pH.
In the third and fourth trials a survey of transport vehicles was
carried out and meat quality of pigs delivered in modern and old-type vehicles was compared. Most trucks examined (78%) were
four years old or more. Few had modern hydraulic lifting gear for
the top decks. Space allowances during transportation were
generally adequate but delays in unloading could, in warm weather,
cause stress on pigs. There was little evidence for an effect of
vehicle on meat quality parameters but day to day variation in
carcass temperature and pH suggested a need for further research
on factory influences on meat quality.
Feeding of Magneium Aspartate to pigs for the last 5 days prior
to slaughter has been shown, in Australia, to have a beneficial
effect on meat colour and drip loss. In the final trial in this study
Mg Asp had no effect on meat quality parameters.European Union Structural Funds (EAGGF
STS in management education: connecting theory and practice
This paper explores the value of science and technology studies (STS) to management education. The work draws on an ethnographic study of second year management undergraduates studying decision making. The nature and delivery of the decision making module is outlined and the value of STS is demonstrated in terms of both teaching method and module content. Three particular STS contributions are identified and described: the social construction of technological systems; actor network theory; and ontological politics. Affordances and sensibilities are identified for each contribution and a discussion is developed that illustrates how these versions of STS are put to use in management education. It is concluded that STS has a pivotal role to play in critical management (education) and in the process offers opportunities for new forms of managin
Inferring Deleterious-Mutation Parameters in Natural Daphnia Populations
Deng and Lynch (1, 2) proposed to characterize deleterious genomic mutations from changes in the mean and genetic variance of fitness traits upon selfing in outcrossing populations. Such observations can be readily acquired in cyclical parthenogens. Selfing and life-table experiments were performed for two such Daphnia populations. A significant inbreeding depression and an increase of genetic variance for all traits analyzed were observed. Deng and Lynch's (2) procedures were employed to estimate the genomic mutation rate (U), mean dominance coefficient ( [Image: see text] ), mean selection coefficient ( [Image: see text] ), and scaled genomic mutational variance ( [Image: see text] ). On average, [Image: see text] , [Image: see text] , [Image: see text] and [Image: see text] (^ indicates an estimate) are 0.84, 0.30, 0.14 and 4.6E-4 respectively. For the true values, the [Image: see text] and [Image: see text] are lower bounds, and [Image: see text] and [Image: see text] upper bounds
Probing Transport Theories via Two-Proton Source Imaging
Imaging technique is applied to two-proton correlation functions to extract
quantitative information about the space-time properties of the emitting source
and about the fraction of protons that can be attributed to fast emission
mechanisms. These new analysis techniques resolve important ambiguities that
bedeviled prior comparisons between measured correlation functions and those
calculated by transport theory. Quantitative comparisons to transport theory
are presented here. The results of the present analysis differ from those
reported previously for the same reaction systems. The shape of the two-proton
emitting sources are strongly sensitive to the details about the in-medium
nucleon-nucleon cross sections and their density dependence.Comment: 23 pages, 11 figures. Figures are in GIF format. If you need
postscript format, please contact: [email protected]
Healthy lifestyle is associated with reduced cardiovascular disease, depression and mortality in people at elevated risk of sleep apnea
OnlinePublWe assessed: (1) the independent and joint association of obstructive sleep apnea risk and healthy lifestyle with common consequences (excessive daytime sleepiness, depression, cardiovascular disease and stroke) of obstructive sleep apnea; and (2) the effect of healthy lifestyle on survival in people with increased obstructive sleep apnea risk. Data from 13,694 adults (median age 46 years; 50% men) were used for cross-sectional and survival analyses (mortality over 15 years). A healthy lifestyle score with values from 0 (most unhealthy) to 5 (most healthy) was determined based on diet, alcohol intake, physical activity, smoking and body mass index. In the crosssectional analysis, obstructive sleep apnea risk was positively associated with all chronic conditions and excessive daytime sleepiness in a doseâresponse manner (p for trend < 0.001). The healthy lifestyle was inversely associated with all chronic conditions (p for trend < 0.001) but not with excessive daytime sleepiness (p for trend = 0.379). Higher healthy lifestyle score was also associated with reduced odds of depression and cardiovascular disease. We found an inverse relationship between healthy lifestyle score with depression (p for trend < 0.001), cardiovascular disease (p for trend = 0.003) and stroke (p for trend = 0.025) among those who had high obstructive sleep apnea risk. In the survival analysis, we found an inverse association between healthy lifestyle and all-cause mortality for all categories of obstructive sleep apnea risk (moderate/high- and high-risk groups [p for trend < 0.001]). This study emphasises the crucial role of a healthy lifestyle in mitigating the effects of obstructive sleep apnea risk in individuals with an elevated obstructive sleep apnea risk.Yohannes Adama Melaku, Sarah Appleton, Amy C. Reynolds, Roger L. Milne, Brigid M. Lynch, Danny J. Eckert, Robert Adam
Archaeological Landscapes during the 10â8 ka Lake Stanley Lowstand on the AlpenaâAmberley Ridge, Lake Huron
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136243/1/gea21590.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136243/2/gea21590_am.pd
Finite element simulation of three-dimensional free-surface flow problems
An adaptive finite element algorithm is described for the stable solution of three-dimensional free-surface-flow problems based primarily on the use of node movement. The algorithm also includes a discrete remeshing procedure which enhances its accuracy and robustness. The spatial discretisation allows an isoparametric piecewise-quadratic approximation of the domain geometry for accurate resolution of the curved free surface.
The technique is illustrated through an implementation for surface-tension-dominated viscous flows modelled in terms of the Stokes equations with suitable boundary conditions on the deforming free surface. Two three-dimensional test problems are used to demonstrate the performance of the method: a liquid bridge problem and the formation of a fluid droplet
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