Personal View: The barn owl — a specialist for studying sensory systems

Neuroforum ◽  
2019 ◽  
Vol 25 (3) ◽  
pp. 213-219 ◽  
Author(s):  
Hermann Wagner
Keyword(s):  
Auditory Processing ◽  
Fruit Fly ◽  
Barn Owl ◽  
Sensory Systems ◽  
Model Systems ◽  
Ecological Niches ◽  
Personal View ◽  
California Institute Of Technology ◽  
Institute Of Technology ◽  
The Impact

Abstract In this personal view article, the impact of an auditory specialist, the barn owl, to our understanding of sensory processing, especially auditory processing, is discussed from the perspective of a long-lasting career. In times when research on model systems such as the mouse or the fruit fly, both generalists for most of the behaviors examined, celebrates big successes, one may ask what the work on animals occupying specialized niches, “specialists”, can contribute to advance our knowledge about sensory systems. A specialist in this context is an animal that occupies a certain ecological niche and shows corresponding adaptations in anatomy and physiology. This article presents a personal view on the impact of the work on such a specialist. In my article I shall focus on audition in the barn owl, a specialist for hunting by listening. I started my scientific career in 1979, working with houseflies, and have worked with barn owls since my time as a postdoc at the California Institute of Technology (“Caltech”, Pasadena, CA, USA) in 1985. My interest in specialists derived from my work as an ornithologist when I realized that adaptations like the long and curved bill of the curlew help animals to occupy certain ecological niches. I wanted to understand in a formal sense, and in comparison to engineering, how evolution shapes such specializations.

On the Impact Behavior of a Material With a Yield Point

1949 ◽  
Vol 16 (1) ◽  
pp. 39-52
Author(s):  
Merit P. White
Keyword(s):  
Yield Stress ◽  
Yield Point ◽  
Impact Behavior ◽  
Longitudinal Impact ◽  
Stress Strain ◽  
California Institute Of Technology ◽  
Static Yield ◽  
Institute Of Technology ◽  
Probable Nature ◽  
The Impact

Abstract An analysis of longitudinal impact tests that were made by Drs. D. S. Clark and P. E. Duwez at the California Institute of Technology on an iron and a steel with definite yield points is described. From this analysis is deduced the probable nature of the dynamic stress-strain relations for such materials. These appear to differ greatly from the static stress-strain relations, unlike the case for materials without yield points. As pointed out by Duwez and Clark, the upper yield stress for undeformed material is several times as great under impact as the static yield stress. The present analysis indicates that under impact, the material with a definite yield point is made harder at a given deformation, and ruptures at a higher (engineering) stress and smaller strain than when loaded statically. The critical impact velocity, defined as that at which nearly instantaneous failure occurs in tension, is discussed, and the factors upon which it depends are given.

Multimodal integration across spatiotemporal scales to guide invertebrate locomotion

2021 ◽  
Author(s):  
Jean-Michel Mongeau ◽  
Lorian E Schweikert ◽  
Alexander L Davis ◽  
Michael S Reichert ◽  
Jessleen K Kanwal
Keyword(s):  
Genetic Model ◽  
Spatial Scales ◽  
Fruit Fly ◽  
Model Systems ◽  
Ecological Niches ◽  
Multimodal Integration ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Challenges And Opportunities ◽  
Spatiotemporal Scales

SYNOPSIS Locomotion is a hallmark of organisms that has enabled adaptive radiation to an extraordinarily diverse class of ecological niches, and allows animals to move across vast distances. Sampling from multiple sensory modalities enables animals to acquire rich information to guide locomotion. Locomotion without sensory feedback is haphazard, therefore sensory and motor systems have evolved complex interactions to generate adaptive behavior. Notably, sensory-guided locomotion acts over broad spatial and temporal scales to permit goal-seeking behavior, whether to localize food by tracking an attractive odor plume or to search for a potential mate. How does the brain integrate multimodal stimuli over different temporal and spatial scales to effectively control behavior? In this review, we classify locomotion into three ordinally ranked hierarchical layers that act over distinct spatiotemporal scales: stabilization, motor primitives, and higher-order tasks, respectively. We discuss how these layers present unique challenges and opportunities for sensorimotor integration. We focus on recent advances in invertebrate locomotion due to their accessible neural and mechanical signals from the whole brain, limbs and sensors. Throughout, we emphasize neural-level description of computations for multimodal integration in genetic model systems, including the fruit fly, Drosophila melanogaster, and the yellow fever mosquito, Aedes aegypti. We identify that summation (e.g. gating) and weighting—which are inherent computations of spiking neurons—underlie multimodal integration across spatial and temporal scales, therefore suggesting collective strategies to guide locomotion.

A baseline Antarctic GIA correction for space gravimetry

2020 ◽  
Author(s):  
Lambert Caron ◽  
Erik Ivins
Keyword(s):  
Mass Balance ◽  
Regional Scale ◽  
California Institute ◽  
Glacial Cycle ◽  
Vertical Movements ◽  
Continental Scale ◽  
Mantle Viscosity ◽  
California Institute Of Technology ◽  
Institute Of Technology ◽  
The Impact

<p class="western"><span>Within the past decade, newly collected GPS data and geochronological constraints have resulted in refinement of glacial isostatic adjustment (GIA) models for Antarctica. These are critical to understanding ice mass changes at present-day. A correction needs to be made when using space gravity for ice mass balance assessments as any vertical movements of the solid Earth masquerade as changes in ice mass, and must be carefully removed. The main upshot of the new Antarctic GIA models is a downward revision of negative ice mass trends deduced from the Gravity Recovery and Climate Experiment (GRACE), resulting from a reduced GIA correction. This revision places GRACE inferred trend in mass balance within the 1-σ uncertainty of mass balance deduced by altimetry. Because uncertainties in Holocene ice history and the low viscosity rheology beneath the West Antarctic Ice Sheet (WAIS) continue to vex further improvement in predictions of present-day GIA gravity rate, more emphasis has been given to regional-scale GIA models. Here we use a Bayesian method to explore the gravimetric GIA trend over Antarctica, both with and without the impact of a late Pleistocene Antarctic ice loads, along with the contribution of oceanic loads. We call this model without loads associated with Antarctica a baseline for regional GIA models to build upon. We consider variations of the radial mantle viscosity profile and the volume of continental-scale ice sheets during the last glacial cycle. The modeled baseline GIA is mainly controlled by the lower mantle viscosity and continental levering caused by ocean loading. We find that the predicted baseline GIA correction weakly depends on the ice history. This correction averages to +28.4 [16.5–41.9, 95% confidence] Gt/yr. In contrast, with Pleistocene Antarctic-proximal ice included, the total modeled mass trend due to GIA is +73.7 [30.1–114.7] Gt/yr. A baseline GIA correction of 28.4 Gt/yr is of order 50% of the mean net mass trend measured during the period 1992-2017. The statistical analysis provides tools for synthesizing any regional Antarctic GIA model with a self-consistent far-field component. This may prove important for accounting for both global and regional 3-D variations in mantle viscosity.</span></p> <p class="western"><span>© 2020 California Institute of Technology.<br />Government sponsorship acknowledged. This work was performed at the California Institute of Technology's Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration's Cryosphere Science Program. </span></p>

Automated mineral analysis in TASK8

1990 ◽  
Vol 48 (2) ◽  
pp. 212-213
Author(s):  
William F. Chambers ◽  
Arthur A. Chodos ◽  
Roland C. Hagan
Keyword(s):  
National Laboratory ◽  
Control Program ◽  
Mineral Analysis ◽  
Alamos National Laboratory ◽  
Mineral Phase ◽  
Los Alamos National Laboratory ◽  
California Institute Of Technology ◽  
Mineral Phases ◽  
Letter Code ◽  
Institute Of Technology

TASK8 was designed as an electron microprobe control program with maximum flexibility and versatility, lending itself to a wide variety of applications. While using TASKS in the microprobe laboratory of the Los Alamos National Laboratory, we decided to incorporate the capability of using subroutines which perform specific end-member calculations for nearly any type of mineral phase that might be analyzed in the laboratory. This procedure minimizes the need for post-processing of the data to perform such calculations as element ratios or end-member or formula proportions. It also allows real time assessment of each data point.The use of unique “mineral codes” to specify the list of elements to be measured and the type of calculation to perform on the results was first used in the microprobe laboratory at the California Institute of Technology to optimize the analysis of mineral phases. This approach was used to create a series of subroutines in TASK8 which are called by a three letter code.

scholarly journals Gut-Ex-Vivo system as a model to study gluten response in celiac disease

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mara Gagliardi ◽  
Nausicaa Clemente ◽  
Romina Monzani ◽  
Luca Fusaro ◽  
Eleonora Ferrari ◽  
...  
Keyword(s):  
Celiac Disease ◽  
Intestinal Epithelium ◽  
Complex Disease ◽  
Ex Vivo ◽  
Dynamic Condition ◽  
Model Systems ◽  
In Vivo Models ◽  
Effective Manner ◽  
Junction Protein ◽  
The Impact

AbstractCeliac disease (CD) is a complex immune-mediated chronic disease characterized by a consistent inflammation of the gastrointestinal tract induced by gluten intake in genetically predisposed individuals. Although initiated by the interaction between digestion-derived gliadin, a gluten component, peptides, and the intestinal epithelium, the disorder is highly complex and involving other components of the intestine, such as the immune system. Therefore, conventional model systems, mainly based on two- or three-dimension cell cultures and co-cultures, cannot fully recapitulate such a complex disease. The development of mouse models has facilitated the study of different interacting cell types involved in the disorder, together with the impact of environmental factors. However, such in vivo models are often expensive and time consuming. Here we propose an organ ex vivo culture (gut-ex-vivo system) based on small intestines from gluten-sensitive mice cultivated in a dynamic condition, able to fully recapitulate the biochemical and morphological features of the mouse model exposed to gliadin (4 weeks), in 16 h. Indeed, upon gliadin exposure, we observed: i) a down-regulation of cystic fibrosis transmembrane regulator (CFTR) and an up-regulation of transglutaminase 2 (TG2) at both mRNA and protein levels; ii) increased intestinal permeability associated with deregulated tight junction protein expression; iii) induction and production of pro-inflammatory cytokines such as interleukin (IL)-15, IL-17 and interferon gamma (IFNγ); and iv) consistent alteration of intestinal epithelium/villi morphology. Altogether, these data indicate that the proposed model can be efficiently used to study the pathogenesis of CD, test new or repurposed molecules to accelerate the search for new treatments, and to study the impact of the microbiome and derived metabolites, in a time- and cost- effective manner.

scholarly journals Experimental Models to Study COVID-19 Effect in Stem Cells

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 91
Author(s):  
Rishi Man Chugh ◽  
Payel Bhanja ◽  
Andrew Norris ◽  
Subhrajit Saha
Keyword(s):  
Stem Cells ◽  
Ex Vivo ◽  
Drug Efficacy ◽  
Cell Loss ◽  
Experimental Models ◽  
Model Systems ◽  
Virus Infectivity ◽  
Ex Vivo Model ◽  
Global Pandemic ◽  
The Impact

The new strain of coronavirus (severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)) emerged in 2019 and hence is often referred to as coronavirus disease 2019 (COVID-19). This disease causes hypoxic respiratory failure and acute respiratory distress syndrome (ARDS), and is considered as the cause of a global pandemic. Very limited reports in addition to ex vivo model systems are available to understand the mechanism of action of this virus, which can be used for testing of any drug efficacy against virus infectivity. COVID-19 induces tissue stem cell loss, resulting inhibition of epithelial repair followed by inflammatory fibrotic consequences. Development of clinically relevant models is important to examine the impact of the COVID-19 virus in tissue stem cells among different organs. In this review, we discuss ex vivo experimental models available to study the effect of COVID-19 on tissue stem cells.

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