Relative Importance Of Controls Research Articles

Higher mosquito production in low-income neighborhoods of Baltimore and Washington, DC: understanding ecological drivers and mosquito-borne disease risk in temperate cities.

Mosquito-vectored pathogens are responsible for devastating human diseases and are (re)emerging in many urban environments. Effective mosquito control in urban landscapes relies on improved understanding of the complex interactions between the ecological and social factors that define where mosquito populations can grow. We compared the density of mosquito habitat and pupae production across economically varying neighborhoods in two temperate U.S. cities (Baltimore, MD and Washington, DC). Seven species of mosquito larvae were recorded. The invasive Aedes albopictus was the only species found in all neighborhoods. Culex pipiens, a primary vector of West Nile virus (WNV), was most abundant in Baltimore, which also had more tire habitats. Both Culex and Aedes pupae were more likely to be sampled in neighborhoods categorized as being below median income level in each city and Aedes pupae density was also greater in container habitats found in these lower income neighborhoods. We infer that lower income residents may experience greater exposure to potential disease vectors and Baltimore residents specifically, were at greater risk of exposure to the predominant WNV vector. However, we also found that resident-reported mosquito nuisance was not correlated with our measured risk index, indicating a potentially important mismatch between motivation needed to engage participation in control efforts and the relative importance of control among neighborhoods.

An Evaluation of the Effects of Experimenter Control of Objects on Individuals’ Engagement in Object Stereotypy

In two experiments, the authors evaluated the extent to which (a) individuals preferred engaging in object stereotypy versus observing an experimenter while the experimenter engaged in object stereotypy and (b) an experimenter's engagement in object stereotypy decreased the participants' engagement in object stereotypy. Results of Experiment 1 indicated that behaver-controlled (BC) object stereotypy was preferred over experimenter-controlled (EC) object stereotypy by three of four participants. Results of Experiment 2 indicated that EC object stereotypy decreased object stereotypy for only one of three participants. Implications of these findings for determining the relative importance of control over stimulation generated by stereotypy are briefly discussed.

Sea-level, topographical and sediment supply controls on Holocene sediment composition in the Humber Estuary, UK

To increase our understanding of the relative control of antecedent topography, sediment supply and sea-level change on grain size and organic content in the Humber Estuary, the composition of its Holocene fill over space and time has been evaluated. A model based-upon bed-by-bed description of over 3,500 bore holes was sub-horizontally 'sliced' to analyse the composition of sediments in different parts of the estuary across the entire fill, as well as solely within estuary marginal sequences. Results demonstrate that different physio-graphic parts of the estuary are characterized by distinctive vertical sediment profiles that reflect the relative control of antecedent topography as well as sea-level upon them. The results raise questions about the processes controlling sand and gravel abundance in marginal sequences, where the estuary is physio-graphically most constrained. This semi-quantitative evaluation, the first of its kind on an estuarine fill, provides a technique for interpreting the relative importance of controls on an estuarine system, but highlights the need for improved modelling of estuarine channel form and dynamics over centurial to millennial time-scales.

Biodiversity and the history of reefs

Current biodiversity estimates suggest that modern coral reefs house between 4 and 5% of all described species, although increasingly sophisticated molecular techniques may reveal the actual diversity to be far higher. The origins and maintenance of this considerable taxonomic biodiversity remain, however, poorly known, particularly as the relative importance of controls that maintain the structure of reef communities differ according to the scale of consideration. The diversity of local coral reef communities is strongly correlated with water depth and differences between habitats. Ecological structure is considered to be ordered mainly by interspecific interactions and differential responses to disturbance, whereas determinants of diversity at regional geographical scales include variation in rates of dispersal and recruitment from the available metapopulation. On evolutionary timescales, historical events such as unique radiations of key taxa and mass extinctions appear to be the main controls on biodiversity change. All these processes operate simultaneously, and must be integrated in order to gain an understanding of the evolutionary perspective. Depending upon the scale of population considered, reef communities may operate as both individualistic assemblages of taxa with similar requirements, and as more tightly integrated ecological entities. Copyright © 2001 John Wiley & Sons, Ltd.

Biodiversity and the history of reefs

AbstractCurrent biodiversity estimates suggest that modern coral reefs house between 4 and 5% of all described species, although increasingly sophisticated molecular techniques may reveal the actual diversity to be far higher. The origins and maintenance of this considerable taxonomic biodiversity remain, however, poorly known, particularly as the relative importance of controls that maintain the structure of reef communities differ according to the scale of consideration. The diversity of local coral reef communities is strongly correlated with water depth and differences between habitats. Ecological structure is considered to be ordered mainly by interspecific interactions and differential responses to disturbance, whereas determinants of diversity at regional geographical scales include variation in rates of dispersal and recruitment from the available metapopulation. On evolutionary timescales, historical events such as unique radiations of key taxa and mass extinctions appear to be the main controls on biodiversity change. All these processes operate simultaneously, and must be integrated in order to gain an understanding of the evolutionary perspective. Depending upon the scale of population considered, reef communities may operate as both individualistic assemblages of taxa with similar requirements, and as more tightly integrated ecological entities. Copyright © 2001 John Wiley & Sons, Ltd.

The use of linear multi-input/multi-output control theory to study posture control

Summary form only given. It is argued that recent results in linear multi-input/multi-output (MIMO) control theory provide new insights into the control of posture and that these methods can provide even more insight once they begin to motivate experiments. The first step in applying linear MIMO control theories to the control of posture is to create a mathematical model of the dynamic system to be controlled. Such a model, in the absence of simplifying assumptions, would be nonlinear and of very high state dimension. The size of the problem can be dealt with by focusing on a particular aspect that is fairly independent, such as the control of the posture of one leg. It is then at least plausible that the effect of the neglected portions of the system is only to perturb the controller for the leg. The next step is to model the sensors and to determine which states are available to the controller. A linear state-feedback control theory based on the linear quadratic regular (LQR) is discussed. This theory produces linear state-feedback controls that minimize a quadratic performance measure. The performance measure has some designer specified parameters that can be used to vary the relative importance of control versus state errors. This approach has been used to derive optimal linear state-feedback controls for regulating the posture of the 36 state limb model. >