2,576 research outputs found
Data from: Contextualizing macroecological laws: A big data analysis on electrofishing and allometric scalings in Ohio, USA
No full textWe investigated the influence of different electrofishing methods on allometric scaling features of fish assemblages in lotic environments. The ultimate aim was to elucidate to which extent the structure of fish assemblages is predictable by the three-quarter power law theory. Water bodies across the state of Ohio, USA, provided a suitable data set to analyze the size–biomass spectra of 2051 fish assemblages. For the first time, 41,070 allometric field observations were screened according to sampling methods (i.e., longline, tote barge, boat) adopted for sampling collection. Allometric patterns varied considerably in relation with the sampling method, in turn imposed by the local hydrology and morphology of the investigated water courses, as shown by the lowering of scalings from boatable to wadeable systems. There are several lines of evidence indicating that the chosen type of electrofishing acts as a pitfall for size spectra. Using individually weighted body-mass values as independent predictor of spectra we show that the specific sampling methodology required by the physical characteristics of different lotic habitats influence the allometric outcomes, a novel result that makes universality of community power laws not as straightforward as supposed until now
Detrital Dynamics and Cascading Effects on Supporting Ecosystem Services
No full textTop-down trophic cascades are well known in many autotrophic systems, yet their role in heterotrophic food webs is less clear. We collated data from 78 investigations and applied meta-analysis to evaluate the strength of detrital trophic cascades in freshwater and terrestrial food webs. Predators exerted significant, indirect controls on detrital resources, in line with theoretical predictions, whereas this was not the case for omnivores, suggesting that detritivory prevailed over predation and disrupted trophic cascades. Significant relationships were observed for both types of consumer in terms of their responses to detrital quality: specifically, unimodal curves across C:N and N:P gradients were the best fits for predators, whilst cascade strength responses to detrital quality were saddle shaped. These insights suggest that while predatory strategy is determining cascades within detrital-based systems, resource quality has bottom-up role effects on predators and on preferential consumption by omnivores. As such, these environmental responses seem to mirror some provisioning and supporting services; our findings are discussed within conceptual frameworks related to ecological stoichiometry and ecosystem services
Contextualizing macroecological laws: A big data analysis on electrofishing and allometric scalings in Ohio, USA
No full textWe investigated the influence of different electrofishing methods on allometric scaling features of fish assemblages in lotic environments. The ultimate aimwas to elucidate to which extent the structure of fish assemblages is predictable by the three-quarter power law theory. Water bodies across the state of Ohio, USA, provided a suitable data set to analyze the size–biomass spectra of 2051 fish assemblages. For the first time, 41,070 allometric field observations were screened according to sampling methods (i.e., longline, tote barge, boat) adopted for sampling collection. Allometric patterns varied considerably in relation with the sampling method, in turn imposed by the local hydrology and morphology of the investigated water courses, as shown by the lowering of scalings from boatable to wadeable systems. There are several lines of evidence indicating that the chosen type of electrofishing acts as a pitfall for size spectra. Using individually weighted body-mass values as independent predictor of spectrawe show that the specific sampling methodology required by the physical characteristics of different lotic habitats influence the allometric outcomes, a novel result that makes universality of community power laws not as straightforward as supposed until now
Decontextualizing big data for a better perception of macroecology
No full textFish species are charismatic subjects widely used for ecological assessment and modelling. We investigated the influence of electrofishing in an attempt to illuminate the extent to which datasets might be merged together. Three American Midwestern regions in Ohio were chosen as study area and the changes in the size-biomass spectra of more than 2000 fish assemblages were analysed. These communities behaved differently according to the sampling method in conjunction to the morphology of the investigated streams and rivers, as shown by decreasing predatory species and lowering of allometric slopes. There are here several lines of evidence indicating that the chosen sampling method, as determined by different habitats, acts as a pitfall and strongly influences the allometry of fish spectra. In the ongoing data-rich era, our results highlight that macroecological investigations, often performed by machine-learning systems without considering the different procedures adopted to collect original data, can easily produce artefactual allometric scalings
Parasyntax and the sentential level in axiomatic functionalism
No full textThis thesis is presented as a contribution to the St Andrews School
of Linguistics, Axiomatic Functionalism, as developed by Mulder and
Hervey. It is essentially a piece of Theoretical Linguistics which
outlines an approach to the hitherto undeveloped areas of Parasyntax
and the Sentential Level in Axiomatic Functionalism.
The theoretical arguments are supported by descriptive hypotheses
concerning the nature of Spoken English. These descriptions are
corpus-based.
The conclusion reached by the author is that not only are Parasyntax
and the Sentential Level distinct in theory (this is axiomatic), but
they are also distinct in their application as regards methodology
and description. This conclusion will undoubtedly prove to be
controversial in the light of recent developments in Axiomatic
Functionalism concerning the Postulates in particular (of which the
author was at the time of writing unaware), and in the light of
other Functionalist approaches to the nature of intonation and
sentences.
It is anticipated that this thesis will be of value to those
interested in Functionalism as well as those concerned with
intonation and the levels of language beyond syntax
Unleashing the Passion of Young People in Your Church is Possible!
No full textBased on groundbreaking research with more than 250 of the nation’s leading congregations, Growing Young provides a strategy any church can use to involve and retain teenagers and young adults. Co-author Jake Mulder shows ministry leaders how to engage younger generations in a way that breathes vitality, life, and energy into the whole church
Responding to Neighborhood Change: CRC Congregations in Southeast Grand Rapids, 1970-2000
No full textSociology professors Dr. Mark Mulder, Calvin College, and Dr. Kevin Dougherty, Baylor University, examined 30 years worth of change in 14 Christian Reformed congregations in Southeast Grand Rapids, Michigan. Mulder and Dougherty will discuss their research finding and conclusions, addressing issues that include adaptation, institutional interrelationships, and the contingent nature of competitive advantage
Haptic gas pedal feedback for active car-following support
No full textThe research presented in this dissertation focuses on supporting drivers in the longitudinal control of their vehicle during car-following. The goal of the research is the human-centred development of a haptic gas pedal interface that comfortably supports drivers in maintaining a safe separation with a leading vehicle during car-following. Two different approaches were found to be suitable for implementation as haptic information providers through the gas pedal. The first approach was to add a force to the gas pedal dynamics which would have to be related to the safe-field-of-travel ahead of the own vehicle and changes therein. The gas pedal dynamics, that is, the force/pedal-position relationship is not changed by this approach. The second approach was to change the stiffness of the gas pedal by adding a virtual stiffness to the inherent stiffness of the gas pedal. By doing so, the dynamics of the gas pedal are changed depending on the changes detected in the safe-field-of-travel. In both approaches, an electrical actuator provides the additional force or stiffness. The main hypothesis of this dissertation is the assumption that with the appropriate haptic feedback of longitudinal traffic information drivers will adopt a force-task in controlling the haptic gas pedal. Experimental verification leads to the conclusion that the stiffness feedback design with time-to-contact information scaled by time headway performs best in this respect.Aerospace Engineerin
Cybernetics of Tunnel-in-the-Sky Displays
No full textConsensus is growing that the flexibility gained with the introduction of programmable, electronic cockpit displays in the 1980s must be exploited to the full extent. An important candidate to become the primary flight display of future flight decks is the tunnel-in-the-sky display, a perspective flight-path display that shows the reference trajectory to be flown in a synthetic three-dimensional world. The usefulness of the tunnel display in the pilot manual aircraft control task is the subject of this thesis. The mainstream of tunnel display research is confined to empirical comparisons of the tunnel display with conventional displays. The approach taken in the present theoretical and experimental study is original and new as it is conducted from the perspective of cybernetics. A four-stage methodology is developed to study the fundamental characteristics of pilot/display interaction, based on a theoretical analysis of information, in particular the information used for control. The information analysis is conducted within the context of Gibson's ecological approach to visual perception. The information analysis provides novel insights into how the tunnel display geometric design variables can affect pilot behavior. To examine the validity of the theoretical hypotheses, six experiments have been conducted. Three experiments examined the effects of manipulating some of the main display design variables, such as the tunnel size, the viewing volume and the presence of guidance symbology. Another three experiments investigated the fundamental characteristics of the tunnel geometrical design in the tasks of following a trajectory that is either straight or circular, and in the task of conducting a curve-interception maneuver. The experiments show that the cybernetic, information-centered approach is indeed very successful in pin-pointing the important characteristics of pilot/display interaction. The experimental methodology employed in this thesis aimed at integrating the model-based approach with the common approach of collecting mainly performance-related data. It is described in detail how experiments can be designed with the objective of conducting a control-theoretic analysis. The limitations of some non-parametric identification methods in multi-axis, multiple loop tracking tasks are described. The use of criterion functions, in both the frequency and the time domain, in the parametric identification methods is also exemplified.Aerospace Engineerin
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