Review: Do the Different Sensory Areas within the Cat Anterior Ectosylvian Sulcal Cortex Collectively Represent a Network Multisensory Hub?

Current theory supports that the numerous functional areas of the cerebral cortex are organized and function as a network. Using connectional databases and computational approaches, the cerebral network has been demonstrated to exhibit a hierarchical structure composed of areas, clusters and, ultimately, hubs. Hubs are highly connected, higher-order regions that also facilitate communication between different sensory modalities. One region computationally identified network hub is the visual area of the Anterior Ectosylvian Sulcal cortex (AESc) of the cat. The Anterior Ectosylvian Visual area (AEV) is but one component of the AESc that also includes the auditory (Field of the Anterior Ectosylvian Sulcus - FAES) and somatosensory (Fourth somatosensory representation - SIV). To better understand the nature of cortical network hubs, the present report reviews the biological features of the AESc. Within the AESc, each area has extensive external cortical connections as well as among one another. Each of these core representations is separated by a transition zone characterized by bimodal neurons that share sensory properties of both adjoining core areas. Finally, core and transition zones are underlain by a continuous sheet of layer 5 neurons that project to common output structures. Altogether, these shared properties suggest that the collective AESc region represents a multiple sensory/multisensory cortical network hub. Ultimately, such an interconnected, composite structure adds complexity and biological detail to the understanding of cortical network hubs and their function in cortical processing

A New Way to Quantify Stratosphere-Troposphere Coupling in Observations and Climate Models

Atmospheric mass is transported in and out of the stratospheric polar cap region by a wave-driven meridional circulation. Using composites of polar cap pressure anomalies, defined as deviations from the average annual cycle, it is shown that this stratospheric mass flux is accompanied by a similar mass flux near the surface. This 'tropospheric amplification' of the stratospheric signal is introduced as a new way to quantify stratosphere-troposphere coupling. Regression analysis is used to create a vertical profile of atmospheric pressure during a tropospheric amplification event, and the regression slope profile is used as a tool to quantify the amplification. Using data from 5 reanalysis datasets and 11 climate models, it is shown that high-top models, with a model lid of above 1 hPa, are significantly better at reproducing tropospheric amplification than low-top models, due to having more detailed parameterisations of stratospheric processes. However, the regression slope profiles of all models, bar one, are significantly different to the profile of reanalysis data at a 95% confidence level. Tropospheric amplification is also investigated in historical and future simulations from these models, and it is concluded that there is not expected to be a large change in the phenomenon over the next 100 years. The processes needed to reproduce tropospheric amplification can be identified by comparing idealised models of different complexity. A simple dry-core model is not able to reproduce tropospheric amplification, while a model with a comprehensive radiation scheme does produce the basic regression slope profile under certain configurations. The associations between pressure change and mass flux are further investigated using primitive equations. It is found that vertical and horizontal contributions to mass flux act to mostly cancel each other out, leaving a poorly-conditioned residual, and that the horizontal mass flux across the polar cap boundary has both geostrophic and ageostrophic components

The Relationship between Nutrition Knowledge and Performance Measures in British Collegiate American Football Athletes

The purpose of this thesis was to ascertain whether or not a significant relationship exists between nutrition knowledge and athletic performance among British collegiate American football athletes. In order to quantify an athlete’s nutrition knowledge and overall performance ability, a nutrition knowledge questionnaire was developed and a new performance assessment tool (Euclid) was evaluated. The nutrition knowledge questionnaire was developed using validation and reliability procedures. From the initial thirty-four questions, nine were removed due to a lack of significance shown when testing for construct validity, and a further two were also removed following the results of tests for internal consistency. The remaining twenty-three questions formed the valid and reliable questionnaire that was utilised to quantify an athlete’s nutrition knowledge. Next, the Euclid model was evaluated as a way of quantifying overall athletic performance in American football in comparison with previously used methods in this area of research. The greatest support for the model’s applicability came from the observed significant relationships between Euclid scores and competitive experience among offensive and defensive starters (n = 6, r = 0.922, p = 0.026; n = 4, r = 0.999, p = 0.022). While significance was not consistently observed between the Euclid performance scores and other control methods, the results warranted further examination of the model. When the nutrition knowledge questionnaire and the Euclid model were used with a British collegiate American football population, results were found to suggest the existence of a relationship between some of the variables. The offensive athletes demonstrated a significant relationship between nutrition knowledge and performance scores (n = 16; r = -0.610, p = 0.012). However, as significance was not observed for the whole group, or for the defensive athletes, further research will be required to discover the true impact of nutrition knowledge on athletic performance in American football

Hierarchical Geostatistics and Multifacies Systems: Boise Hydrogeophysical Research Site, Boise, Idaho

The geostatistical structure of a heterogeneous coarse fluvial aquifer is investigated with porosity data derived from neutron logs at a research well field (Boise Hydrogeophysical Research Site, or BHRS) that was designed, in part, to support three-dimensional geostatistical analysis of hydrologic and geophysical parameters. Recognizing that the coarse fluvial deposits include subdivisions (units between bounding surfaces), we adopt a hierarchical approach and examine the porosity geostatistics of the aquifer at three scales. At the BHRS, the saturated fluvial deposits as a whole (maximum interwell spacing ~80 m, thickness ~16–18 m) are at hierarchical level 1; five subhorizontal units within these deposits (four cobble-dominated units and a channel sand) can be traced across the central area of the BHRS and are at hierarchical level 2; and subunits (patches or lenses) in one of the level 2 units (Unit 4), are at hierarchical level 3. We use variography and porosity statistics to recognize nonstationarity at hierarchical level 1 and in one of the level 2 units (Unit 4) where the means and variances of porosity differences as a function of lag are not constant between distinct units and subunits, respectively. The geostatistical structure at level 1 is modeled with different horizontal and vertical structures that have different sills (vertical sill greater than horizontal sill). The difference in sills can be explained quantitatively by the summing of weighted sills from all individual units and combined units (i.e., a given pair of different units), where the weights are the proportions of data pairs contributing to the sills at each lag from the individual and combined units. Extension of this analysis leads to a weighted, multistructure form of the variogram function whereby a global experimental variogram in a hierarchical system can be decomposed quantitatively into weighted component individual- and combined-unit (or facies) structures for any number of units or hierarchical levels. Such decomposition of the global horizontal variogram from the BHRS indicates that short-range periodicity in that structure is due to both (1) combined-unit structures associated with patches or lenses at hierarchical level 3 in Unit 4 and (2) variations in thickness of Unit 2. For hierarchical multifacies systems, structure models fit to global horizontal and vertical experimental variograms may not be useful for subsequent stochastic modeling if the system on which the structure models are based is nonstationary

Interactions Between Sediment Mechanical Structure and Infaunal Community Structure Following Physical Disturbance

Shallow, river-influenced coastal sediments are important for global carbon storage and nutrient cycling and provide a habitat for diverse communities of invertebrates (infauna). Elevated bed shear stress from extreme storms can resuspend, transport, and deposit sediments, disrupting the cohesive structure of muds, and sorting and depositing sand eroded from beaches. These physical disruptions can also resuspend or smother infauna, decreasing abundances and changing community structure. Infaunal activities such as burrowing, tube construction, and feeding can impact sediment structure and stability. However, little is known about how physical disturbance impacts short and long-term sediment habitat suitability and whether disturbance-tolerant infauna influence sediment restabilization and community recovery. This dissertation investigated how infaunal communities recover following physical disturbance. Temporal changes to the geological and geotechnical structure of muds following manipulated resuspension were assessed in a laboratory experiment. Growth of small-bodied infauna delayed sediment restabilization by increasing erosion and reducing sediment bulk density but increasing cohesion. The remainder of this dissertation investigated short and long-term changes to infaunal community and sediment structure at 5-20 m depths in the northern Gulf of Mexico following Hurricanes Sally and Zeta (2020). A field survey was conducted to assess sediment structure and infaunal community structure before and after the storms. Substantial site-to-site variability in post-storm sediment property changes was consistent with flow interactions driven by local bathymetry leading to sand transport to some sites and near-surface fine sediment loss or little change at other sites. However, despite the variability in hurricane-induced sedimentary changes and persistence of post-storm impacts 8 months after Sally, there were few direct impacts on infaunal abundance, diversity, or community similarity that were consistent with the magnitude of sedimentary change. The lack of direct storm impacts to infauna may have resulted from a combination of pre-Sally disturbances, seasonal infaunal dynamics, and most taxa being tolerant of dynamic river-influenced coastal sediments. Linking infaunal community structure and sediment structure changes over time after extreme storms is important for understanding sediment stability and transport dynamics in frequently disturbed coastal sediments, especially because storm intensity is expected to increase with climate change

Boise Hydrogeophysical Research Site (BHRS): Objectives, Design, Initial Geostatistical Results

The Boise Hydrogeophysical Research Site (BHRS) is a wellfield developed in a shallow, coarse (cobble-and-sand), alluvial aquifer with the goal of developing cost-effective methods for quantitatively characterizing the distribution of permeability in heterogeneous aquifers using hydrologic and geophysical techniques. Responses to surface geophysical techniques (e.g., seismic, radar, transient electromagnetics) will be calibrated against a highly characterized control volume (the wellfield) with 3-D distributions of geologic, hydrologic, and geophysical properties determined from extensive field measurements. Also, these data sets will be used to investigate relationships between properties and to test petrophysical models. Well coring and construction methods, and the well arrangement in the field, are designed to provide detailed control on lithology and to support a variety of single-well, crosshole, and multiwell geophysical and hydrologic tests. Wells are screened through the cobble-and-sand aquifer to a clay that underlies the BHRS at about 20 m depth. In addition, the wellfield design optimizes well-pair distances and azimuths for determination of short-range geostatistical structure. Initial geostatistical analysis of porosity data derived from borehole geophysical logs indicates that the omnidirectional horizontal experimental variogram for porosity (possible proxy for log permeability) is best fit with a nested periodic model structure