Hunting by expectation or optimal foraging: A study of patch use by chickadees

When a predator exploits an environment in which food is patchily distributed, it has to continually make the decision of how long to stay in a patch. In this paper we examine this question using black-capped chickadees foraging in a large aviary for small pieces of mealworm hidden in artificial pine cones. The results of our experiments show the following: (a) when the birds encounter a long sequence of patches (groups of pine cones) each containing the same number of prey, they do not learn to expect a fixed number of prey per patch (Gibb\u27s hypothesis of hunting by expectation); (b) similarly, the birds do not learn to spend constant time on each patch (although the data on this are less clear cut); (c) the birds have a constant giving-up time (interval between last catch and leaving the patch) for all types of patches within an environment, and the giving-up time is inversely related to the average capture rate for the environment. These two findings are consistent with an optimal foraging model of patch use developed by E.L. Charnov. Thus our results are more consistent with the predictions of the optimal foraging than with the hypothesis of hunting by expectation

Benefits of Looking for Coincident Events, Taus, and Muons with the Askaryan Radio Array

Ultra-High Energy (UHE) neutrinos over $10^{16}$ eV have yet to be observed but the Askaryan Radio Array (ARA) is one in-ice neutrino observatory attempting to make this discovery. In anticipation of a thorough full-observatory and full-livetime neutrino search, we estimate how many neutrino events can be detected accounting for secondary interactions, which are typically ignored in UHE neutrino simulations. Using the NuLeptonSim and PyREx simulation frameworks, we calculate the abundance and usefulness of cascades viewed by multiple ARA stations and observations made of taus, muons, and neutrinos generated during and after initial neutrino cascades. Analyses that include these scenarios benefit from a considerable increase in effective area at key ARA neutrino energies, one example being a 30% increase in ARA's effective area when simulating taus and muons produced in $10^{19}$ eV neutrino interactions. These analysis techniques could be utilized by other in-ice radio neutrino observatories, as has been explored by NuRadioMC developers. Our contribution showcases full simulation results of neutrinos with energies $3\times10^{17}$ - $10^{21}$ eV and visualizations of interesting triggered event topologies.Comment: For 2023 ICRC, 8 pages, 7 figures, 1 tabl

Robotic task-specific training of the upper extremity in children with Cerebral Palsy

poster abstractBackground: Cerebral Palsy (CP) affects at least 2 in 1,000 children in the United States. The disorder is non-progressive, yet secondary impairments can worsen over time leading to contracture, decreased strength, increased tone and ultimately, impaired mobility and function. Robotic therapy has been found to have positive outcomes for similar impairments in stroke neuro-recovery, suggesting the need for the application of this technology to CP. Purpose: The purpose of this study was to investigate whether specific upper extremity (UE) robotic training improves UE function in children with CP. Methods: This is an ongoing study currently with 5 children (ages 4-12) with CP that have completed the treatment intervention. Inclusion criteria included a hemiplegic presentation of the UE, a modified Ashworth scale (MAS) score of 2 or less and wrist extension equal to or greater than 0o in the affected arm, and sufficient cognition to attain to a task for 40-60 minutes. Each child participated in 16 total robotic training sessions occurring twice weekly, with each session consisting of 1,040 task-specific reaching movements of the affected arm with real-time impedance control. Pre- and post-testing and a 1-month follow-up were performed for each subject. Clinical outcome measures included active range of motion (AROM), passive range of motion (PROM), manual muscle tests (MMT), and grip strength, in addition to functional tests including the MAS, adaptive Fugl-Meyer scale, and the Pediatric Evaluation of Disability Inventory (PEDI) assessed by parents. Lastly, spatial-temporal control patterns were collected during each session, allowing for a visual assessment of a child’s progress in refining UE movement patterns to 16 positions across all quadrants. Results: For AROM and PROM, 4 of 5 subjects demonstrated an increase in at least 2 joints by 1-month follow-up. The remaining measurements produced no change or change within the standard error for goniometry (+/- 5o), while no decline was noted in any subjects. Pre-test MMT revealed strength measures ranging from 3/5 to 5/5. By 1-month follow-up, 85% of all measurements were 5/5, with the remaining 15% at 4+/5. For grip strength, 3 of 4 subjects (fifth subject unavailable) doubled their strength by 1-month follow-up, with the last demonstrating symmetry with the unaffected limb. Tone, as measured by MAS, did not appear to be a limiting factor as only 1 child displayed any noticeable tone (MAS of 2) across the measured motions. For the Fugl-Meyer, 4 of 5 subjects improved coordination by more than 2 points by 1- month follow-up, while the fifth maintained throughout the study. Parents reported via the PEDI an overall improvement in performing functional tasks for all children during the study, with 4 of 5 subjects improving by 10 or more points. Lastly, spatial-temporal control patterns showed marked improvement for all subjects by 1-month follow-up. Conclusion: Early results indicate that the application of robotic training to children with CP improved several clinical measures of the affected limb. This likely resulted in increased use of the affected limb, leading to improved functional performance

Consequences of Dam Removal on Mussel Assemblages (Unionidae) in the Cuyahoga River

The primary objective of a new survey of the Cuyahoga River was to assess species richness and population abundance of various mussel species in the family Unionidae throughout the Middle Cuyahoga River and upper parts of the Lower Cuyahoga River. Historically, few records existed for this river between Lake Rockwell and the Cuyahoga Valley National Park, a region in which four dams have been removed in the past 12 years. Timed visual surveys were conducted during low flow conditions and by using tactile techniques in deeper water. Throughout the survey, only 37 live animals were located across the 18 Middle Cuyahoga River sites inspected, which included only Lampsilis siliquoidea, Pyganodon grandis and the state-endangered Ligumia nasuta. No live mussels were found between the Gorge and the Cuyahoga Valley National Park. That 434 shells and valves were collected, and all but two were classifed as long dead, attests that mussels had been more abundant, and that at least nine of the ten species known to be present above Lake Rockwell had lived in the Middle Cuyahoga River. Remote sensing data and aerial photographs were used to characterize change in opening up the river, but benefts to water quality and stream flow subsequent to dam removal must be tempered with the apparent loss of an assemblage of mussels better adapted to lentic conditions

The barium isotopic mixture for the metal-poor subgiant star HD140283

Current theory regarding heavy element nucleosynthesis in metal-poor environments states that the r-process would be dominant. The star HD140283 has been the subject of debate after it appeared in some studies to be dominated by the s-process. We provide an independent measure of the Ba isotope mixture in HD140283 using an extremely high quality spectrum and an extensive chi^2 analysis. We exploit hyperfine splitting of the BaII 4554 \AA\ and 4934 \AA\ resonance lines in an effort to constrain the isotope ratio in 1D LTE. Using the code ATLAS in conjunction with KURUCZ06 model atmospheres we analyse 93 Fe lines to determine the star's macroturbulence. With this information we construct a grid of Ba synthetic spectra and, using a \chi^2 code, fit these to our observed data to determine the isotopic ratio, fodd, which represents the ratio of odd to even isotopes. We also analyse the Eu lines. We set a new upper limit of the rotation of HD140283 at vsin{i}\leq3.9\kms, a new upper limit on [Eu/H] < -2.80 and abundances [Fe/H] = -2.59\pm0.09, [Ba/H] = -3.46\pm0.11. This leads to a new lower limit on [Ba/Eu] > -0.66. We find that, in the framework of a 1D LTE analysis, the isotopic ratios of Ba in HD140283 indicate fodd=0.02\pm0.06, a purely s-process signature. This implies that observations and analysis do not validate currently accepted theory. We speculate that a 1D code, due to simplifying assumptions, is not adequate when dealing with observations with high levels of resolution and S/N because of the turbulent motions associated with a 3D stellar atmosphere. New approaches to analysing isotopic ratios, in particular 3D hydrodynamics, need to be considered when dealing with the levels of detail required to properly determine them. However published 3D results exacerbate the disagreement between theory and observation.Comment: 16 pages, 10 figures, 7 tables, 1 online appendix Accepted by A&

Reversal of left-right asymmetry induced by aberrant nodal signaling in the node of mouse embryos

The node at the anterior tip of the primitive streak serves as an initial generator of the left-right (L-R) axis in mammalian embryos. We now show that a small disturbance in molecular signaling at the node is responsible for the L-R reversal of visceral organs in the inv mutant mouse. In the node of wild-type embryos, the expression of Nodal and Cerl2 (Dand5), which encodes an inhibitor of Nodal, is asymmetric, with the level of Nodal expression being higher on the left side and that of Cerl2 expression higher on the right. In inv/inv embryos, however, a localized reduction in the level of Cerl2 expression results in upregulation of the Nodal signal and a consequent induction of Lefty expression in the node. The ectopic expression of Lefty1 delays the onset of Nodal expression in the lateral plate mesoderm. L-R asymmetry of Cerl2 expression in the node also becomes reversed in a manner dependent on the Nodal signal. Nodal expression in the lateral plate mesoderm then appears on the right side, probably reflecting the balance between Nodal and Cerl2 in the node. The inhibition of Cerl2 expression by the Nodal signal suggests a mechanism for amplification of the cue for L-R asymmetry provided by nodal flow and for stabilization of asymmetric gene expression around the node. In inv/inv embryos, this system may function in reverse as a result of ectopic production of Lefty, which inhibits the Nodal signal on the left side in a manner dependent on leftward nodal flow.Ministry of Education, Culture, Sports, Science, and Technology of Japan; CREST; Kyushu University; Naito Foundationinfo:eu-repo/semantics/publishedVersio