What makes a lizard invasive? Behavioral and neural correlates of invasion success

To understand what makes an invasive species successful, we must understand the behavioral mechanisms these invaders employ. In this study, I examined traits associated with the “boldness” behavioral syndrome (i.e., aggression, general activity levels, and behavioral flexibility), and the morphology of brain regions associated with those traits. I assessed boldness by conducting a series of four behavioral tests designed to measure aggression towards prey, aggression towards a conspecific, overall activity in an open field test, and flexibility in completing a novel task. I compared these measures in two species pairs: the native green anole (Anolis carolinensis; n = 12) and the invasive Cuban brown anole (Anolis sagrei; n = 15), and the native Texas banded gecko (Coleonyx brevis; n = 4) and the invasive Mediterranean house gecko (Hemidactylus turcicus; n = 8). I found that the brown anole was “bolder” than the green anole in two of the four behavioral tests conducted, but there was no difference between the two gecko species for any of the behavioral tests conducted. In contrast to my predictions, the native green anole had a larger relative brain mass (a general indicator of behavioral flexibility) and a relative total brain volume than the invasive brown anole. Green anoles also had larger neuron somas in the ventromedial nucleus of the amygdala and the medial cortex (regions associated with the boldness behaviors), contradicting my predictions. However, the Mediterranean house gecko had a larger relative brain mass than the native Texas banded gecko, consistent with the predicted pattern. I also found several within species relationships between behaviors expressed during the trials and the brain regions with which I predicted they would be associated. Together, these results provide one of the first studies of the relationships between brain and behavior in invasion biology

A DYNAMIC GENERAL EQUILIBRIUM ANALYSIS OF U.S. BIOFUELS PRODUCTION

With the rising global interest in energy security and climate change mitigation, biofuels have gained the prominent attention of researchers and policy makers. The U.S. has emerged as the leading producer of biofuels and is aiming for achieving a target of 36 billion gallons of renewable fuels by 2022 under its updated renewable fuels standard (RFS2) policy. In this paper, we study the longer-term global implications of large-scale renewable fuels production in the U.S. We utilize the GTAP v7.1 data base and introduce a detailed breakdown of agricultural crops, first and second generation biofuels and by-products. We update this fully disaggregated data base to reflect the 2010 global economy, based on secondary data for the sectors and regions included. We adapt the Applied Dynamic Analysis of Global Economy (ADAGE) model developed by Ross (2009) into a recursive dynamic framework and introduce agriculture, biofuels, and land use linkages. We construct a dynamic baseline from 2010 through 2050 in five-year time steps. The dynamics in the model comes from growth in GDP, population, capital accumulation, labor productivity, growth in natural resource stocks, and technological changes in the energy intensive and agricultural sectors. We implement a representative RFS2 policy scenario in the U.S for 2025, using two alternative approaches: (i) RFS permits approach – which assumes biofuels and petroleum fuels are perfect substitutes after adjusting for energy content, and (ii) Target share of biofuels in transportation fuels approach – which treats biofuels and petroleum fuels as imperfect substitutes. Both approaches offer insights regarding potential policy impacts, particularly on the international market and indirect land use change. Because the share approach keeps the biofuels share fixed in the regions outside the U.S., it does not result in dramatic changes in the rest of the world. In the permits approach, however, the regions without a specific policy requiring a given level of biofuels tend to reduce biofuels consumption. This is a result of the reduction in relative price of petroleum products as U.S. policy increases demand for biofuels and reduces global demand for petroleum, making renewable fuels less cost-competitive in the rest of the world.ADAGE, Biofuels, Computable General Equilibrium, Recursive Dynamic, Resource /Energy Economics and Policy,

The Development and Evaluation of a Novel Thoracoscopic Diaphragmatic Hernia Repair Simulator

Background: Thoracoscopic diaphragmatic hernia (DH) repair has a high recurrence rate. Effective simulation modeling may improve technical performance for thoracoscopic DH repair. The study purpose was to evaluate measures of validity evidence for a low-cost thoracoscopic DH simulator. Materials and Methods: Synthetic diaphragm/intestine was connected to a to-scale left-sided neonatal rib cage and then covered with synthetic skin. Forty participants evaluated the DH repair simulator, using survey ratings that were analyzed for test content and internal structure validity evidence. Results: Observed averages (on a scale of 0?5) for the domains were 4.6 for Relevance, 4.5 for Value, 4.3 for Physical attributes, 4.0 for Realism of experience, 3.8 for Realism of materials, and 4.2 for Ability to perform. The highest observed averages were ?relevance to practice? and ?value, testing tool,? whereas the lowest ratings were realism, intestines and realism, diaphragm. The observed average of global opinion ratings was 2.84/4.0, indicating the simulator can be considered for teaching thoracoscopic DH repair but could be improved. Experienced surgeons (more than eight DH repairs, at least four thoracoscopic repairs) had higher overall ratings than inexperienced surgeons (4.4 versus 4.1, P=.001). Conclusions: We successfully created a thoracic space relevant to a thoracoscopic DH repair and completed the model using inexpensive, readily accessible materials. After participants performed a simulated thoracoscopic DH repair, their ratings indicated the simulator was relevant to clinical practice and valuable as a learning tool but still requires improvements. Improvements and additional evaluation of validity evidence (content, internal structure, response processes, and relationship to other variables) are necessary prior to full implementation of this model as an educational tool.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140147/1/lap.2013.0196.pd

The Development and Evaluation of a Novel Thoracoscopic Diaphragmatic Hernia Repair Simulator

Background: Thoracoscopic diaphragmatic hernia (DH) repair has a high recurrence rate. Effective simulation modeling may improve technical performance for thoracoscopic DH repair. The study purpose was to evaluate measures of validity evidence for a low-cost thoracoscopic DH simulator. Materials and Methods: Synthetic diaphragm/intestine was connected to a to-scale left-sided neonatal rib cage and then covered with synthetic skin. Forty participants evaluated the DH repair simulator, using survey ratings that were analyzed for test content and internal structure validity evidence. Results: Observed averages (on a scale of 0?5) for the domains were 4.6 for Relevance, 4.5 for Value, 4.3 for Physical attributes, 4.0 for Realism of experience, 3.8 for Realism of materials, and 4.2 for Ability to perform. The highest observed averages were ?relevance to practice? and ?value, testing tool,? whereas the lowest ratings were realism, intestines and realism, diaphragm. The observed average of global opinion ratings was 2.84/4.0, indicating the simulator can be considered for teaching thoracoscopic DH repair but could be improved. Experienced surgeons (more than eight DH repairs, at least four thoracoscopic repairs) had higher overall ratings than inexperienced surgeons (4.4 versus 4.1, P=.001). Conclusions: We successfully created a thoracic space relevant to a thoracoscopic DH repair and completed the model using inexpensive, readily accessible materials. After participants performed a simulated thoracoscopic DH repair, their ratings indicated the simulator was relevant to clinical practice and valuable as a learning tool but still requires improvements. Improvements and additional evaluation of validity evidence (content, internal structure, response processes, and relationship to other variables) are necessary prior to full implementation of this model as an educational tool.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140147/1/lap.2013.0196.pd

Evaluation of Three Sources of Validity Evidence for a Laparoscopic Duodenal Atresia Repair Simulator

Purpose: Laparoscopic duodenal atresia (DA) repair is a relatively uncommon pediatric operation requiring advanced minimally invasive skills. Currently, there are no commercial simulators available that address surgeons' needs for refining skills associated with this procedure. The purposes of this study were (1) to create an anatomically correct, size-relevant model and (2) to evaluate the content validity of the simulator. Materials and Methods: Radiologic images were used to create an abdominal domain consistent with a full-term infant. Fetal bovine tissue was used to complete the simulator. Following Institutional Review Board exempt determination, 18 participants performed the simulated laparoscopic DA repair. Participants completed a self-report, six-domain, 24-item instrument consisting of 4-point rating scales (from 1=not realistic to 4=highly realistic). Validity evidence relevant to test content and response processes was evaluated using the many-facet Rasch model, and evidence of internal structure (inter-item consistency) was estimated using Cronbach's alpha. Results: The highest observed averages were for ?Value as a training and testing tool? (both observed averages=3.9), whereas the lowest ratings were ?Palpation of liver? (observed average=3.3) and ?Realism of skin? (observed average=3.2). The Global opinion rating was 3.2, indicating the simulator can be considered for use as is, but could be improved slightly. Inter-item consistency was high (α=0.89). Conclusions: We have successfully created a size-appropriate laparoscopic DA simulator. Participants agreed that the simulator was relevant and valuable as a learning/testing tool. Prior to implementing this simulator as a training tool, minor improvements should be made, with subsequent evaluation of additional validation evidence.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140148/1/lap.2014.0358.pd

Evaluation of Three Sources of Validity Evidence for a Synthetic Thoracoscopic Esophageal Atresia/Tracheoesophageal Fistula Repair Simulator

Purpose: Thoracoscopic esophageal atresia (EA)/tracheoesophageal fistula (TEF) repair is technically challenging. We have previously reported our experiences with a high-fidelity hybrid model for simulation-based educational instruction in thoracoscopic EA/TEF, including the high cost of the tissue for these models. The purposes of this study were (1) to create a low-cost synthetic tissue EA/TEF repair simulation model and (2) to evaluate the content validity of the synthetic tissue simulator. Materials and Methods: Review of the literature and computed tomography images were used to create computer-aided drawings (CAD) for a synthetic, size-appropriate EA/TEF tissue insert. The inverse of the CAD image was then printed in six different sections to create a mold that could be filled with platinum-cured silicone. The silicone EA/TEF insert was then placed in a previously described neonatal thorax and covered with synthetic skin. Following institutional review board?exempt determination, 47 participants performed some or all of a simulated thoracoscopic EA/TEF during two separate international meetings (International Pediatric Endosurgery Group [IPEG] and World Federation of Associations of Pediatric Surgeons [WOFAPS]). Participants were identified as ?experts,? having 6?50 self-reported thoracoscopic EA/TEF repairs, and ?novice,? having 0?5 self-reported thoracoscopic EA/TEF repairs. Participants completed a self-report, six-domain, 24-item instrument consisting of 23 5-point rating scales and one 4-point Global Rating Scale. Validity evidence relevant to test content and response processes was evaluated using the many-facet Rasch model, and evidence of internal structure (interitem consistency) was estimated using Cronbach's alpha. Results: A review of the participants' ratings indicates there were no overall differences across sites (IPEG versus WOFAPS, P=.84) or experience (expert versus novice, P=.17). The highest observed averages were 4.4 (Value of Simulator as a Training Tool), 4.3 (Physical Attributes?chest circumference, chest depth, and intercostal space), and 4.3 (Realism of Experience?fistula location). The lowest observed averages were 3.5 (Ability to Perform?closure of fistula), 3.7 (Ability to Perform?acquisition target trocar sites), 3.8 (Physical Attributes?landmark visualization), 3.8 (Ability to Perform?anastomosis and dissection of upper pouch), and 3.9 (Realism of Materials?skin). The Global Rating Scale was 2.9, coinciding with a response of ?this simulator can be considered for use in neonatal TEF repair training, but could be improved slightly.? Material costs for the synthetic EA/TEF inserts were less than $2 U.S. per insert. Conclusions: We have successfully created a low-cost synthetic EA/TEF tissue insert for use in a neonatal thoracoscopic EA/TEF repair simulator. Analysis of the participants' ratings of the synthetic EA/TEF simulation model indicates that it has value and can be used to train pediatric surgeons, especially those early in their learning curve, to begin to perform a thoracoscopic EA/TEF repair. Areas for model improvement were identified, and these areas will be the focus for future modifications to the synthetic EA/TEF repair simulator.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140150/1/lap.2014.0370.pd

Preliminary Evaluation of a Novel Thoracoscopic Infant Lobectomy Simulator

Purpose: Thoracoscopic lobectomy in infants requires advanced minimally invasive skills. Simulation-based education has the potential to improve complex procedural skills without exposing the patient to undue risks. The study purposes were (1) to create a size-appropriate infant lobectomy simulator and (2) to evaluate validity evidence to support or refute its use in surgical education. Materials and Methods: In this Institutional Review Board-exempt study, a size-appropriate rib cage for a 3-month-old infant was created. Fetal bovine tissue completed the simulator. Thirty-three participants performed the simulated thoracoscopic lobectomy. Participants completed a self-report, 26-item instrument consisting of 25 4-point rating scales (from 1=not realistic to 4=highly realistic) and a one 4-point Global Rating Scale. Validity evidence relevant to test content and response processes was evaluated using the many-facet Rasch model, and evidence of internal structure (inter-item consistency) was estimated using Cronbach's alpha. Results: Experienced surgeons (observed average=3.6) had slightly higher overall rating than novice surgeons (observed average=3.4, P=.001). The highest combined observed averages were for the domain Physical Attributes (3.7), whereas the lowest ratings were for the domains Realism of Experience and Ability to Perform Tasks (3.4). The global rating was 2.9, consistent with ?this simulator can be considered for use in infant lobectomy training, but could be improved slightly.? Inter-item consistency for items used to evaluate the simulator's quality was high (α=0.90). Conclusions: With ratings consistent with high physical attributes and realism, we successfully created an infant lobectomy simulator, and preliminary evidence relevant to test content, response processes, and internal structure was supported. Participants rated the model as realistic, relevant to clinical practice, and valuable as a learning tool. Minor improvements were suggested prior to its full implementation as an educational and testing tool.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140149/1/lap.2014.0364.pd

Low Ligand Requirement for Deletion and Lack of Synapses in Positive Selection Enforce the Gauntlet of Thymic T Cell Maturation

SummaryImmature double-positive (CD4+CD8+) thymocytes respond to negatively selecting peptide-MHC ligands by forming an immune synapse that sustains contact with the antigen-presenting cell (APC). Using fluorescently labeled peptides, we showed that as few as two agonist ligands could promote APC contact and subsequent apoptosis in reactive thymocytes. Furthermore, we showed that productive signaling for positive selection, as gauged by nuclear translocation of a green fluorescent protein (GFP)-labeled NFATc construct, did not involve formation of a synapse between thymocytes and selecting epithelial cells in reaggregate thymus cultures. Antibody blockade of endogenous positively selecting ligands prevented NFAT nuclear accumulation in such cultures and reversed NFAT accumulation in previously stimulated thymocytes. Together, these data suggest a “gauntlet” model in which thymocytes mature by continually acquiring and reacquiring positively selecting signals without sustained contact with epithelial cells, thereby allowing them to sample many cell surfaces for potentially negatively selecting ligands

Pump Pulse Bandwidth-Activated Nonlinear Phononic Coupling in CdWO4_4

To control structure-function relationships in solids with light, we must harness the shape of the potential energy surface, as expressed in anharmonic coupling coefficients. We use two-dimensional terahertz (THz) spectroscopy to identify trilinear coupling between sets of vibrational modes in CdWO$_4$. It is generally understood that efficient trilinear coupling occurs when the frequencies of two coupled modes add or subtract to the frequency of the third mode. Interestingly, we observe that this condition is not necessary: the THz driving-pulse itself can activate the coupling by contributing broad frequency content to the initial motion of the excited modes. Understanding that the bandwidth of the driving force can activate energy-flow pathways has broad implications for coherent control of collective modes using intense THz light pulses.Comment: 27 Pages, 15 Figure

Accent modulates access to word meaning: Evidence for a speaker-model account of spoken word recognition

Speech carries accent information relevant to determining the speaker’s linguistic and social background. A series of web-based experiments demonstrate that accent cues can modulate access to word meaning. In Experiments 1-3, British participants were more likely to retrieve the American dominant meaning (e.g., hat meaning of “bonnet”) in a word association task if they heard the words in an American than a British accent. In addition, results from a speeded semantic decision task (Experiment 4) and sentence comprehension task (Experiment 5) confirm that accent modulates on-line meaning retrieval such that comprehension of ambiguous words is easier when the relevant word meaning is dominant in the speaker’s dialect. Critically, neutral-accent speech items, created by morphing British- and American-accented recordings, were interpreted in a similar way to accented words when embedded in a context of accented words (Experiment 2). This finding indicates that listeners do not use accent to guide meaning retrieval on a word-by-word basis; instead they use accent information to determine the dialectic identity of a speaker and then use their experience of that dialect to guide meaning access for all words spoken by that person. These results motivate a speaker-model account of spoken word recognition in which comprehenders determine key characteristics of their interlocutor and use this knowledge to guide word meaning access