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Sex Differences in the Brains of Capuchin Monkeys (\u3cem\u3eSapajus [Cebus] apella\u3c/em\u3e)
No full textThis study reports an analysis of 20 T1-weighted MRI scans from tufted capuchin monkeys (5 male, 15 female). We carried out a data-driven, whole-brain volumetric analysis on regional gray matter anatomy using voxel-based morphometry. This revealed that males showed statistically significant expansion of a region of the hypothalamus, while females showed significant expansion in a distributed set of regions, including the cerebellum, early visual cortex, and higher-order visual regions spanning occipital and temporal cortex. In order to elucidate the network connectivity of these regions, we employed probabilistic tractography on diffusion tensor imaging data. This showed that the female-enlarged regions connect with distributed association networks across the brain. Notably, this contrasts with rodent studies, where sex differences are focused in deep, ancestral limbic regions involved in the control of reproductive behavior. Additionally, in our dataset, for several regions, male and female volumetric measures were completely non-overlapping. This contrasts with human studies, where sex differences in cortical regions have been reported, but are characterized by overlapping rather than divergent male and female values. We suggest that these results can be understood in the context of the different lifetime experiences of males and females, which may produce increased experience-dependent cortical plasticity in capuchins compared to rodents, and in humans compared to capuchins
Season of Prescribed Fire Determines Grassland Restoration Outcomes After Fire Exclusion and Overgrazing
Get PDFFire exclusion and mismanaged grazing are globally important drivers of environmental change in mesic C4 grasslands and savannas. Although interest is growing in prescribed fire for grassland restoration, we have little long-term experimental evidence of the influence of burn season on the recovery of herbaceous plant communities, encroachment by trees and shrubs, and invasion by exotic grasses. We conducted a prescribed fire experiment (seven burns between 2001 and 2019) in historically fire-excluded and overgrazed grasslands of central Texas. Sites were assigned to one of four experimental treatments: summer burns (warm season, lightning season), fall burns (early cool season), winter burns (late cool season), or unburned (fire exclusion). To assess restoration outcomes of the experiment, in 2019, we identified old-growth grasslands to serve as reference sites. Herbaceous-layer plant communities in all experimental sites were compositionally and functionally distinct from old-growth grasslands, with little recovery of perennial C4 grasses and long-lived forbs. Unburned sites were characterized by several species of tree, shrub, and vine; summer sites were characterized by certain C3 grasses and forbs; and fall and winter sites were intermediate in composition to the unburned and summer sites. Despite compositional differences, all treatments had comparable plot-level plant species richness (range 89–95 species/1000 m2). At the local-scale, summer sites (23 species/m2) and old-growth grasslands (20 species/m2) supported greater richness than unburned sites (15 species/m2), but did not differ significantly from fall or winter sites. Among fire treatments, summer and winter burns most consistently produced the vegetation structure of old-growth grasslands (e.g., mean woody canopy cover of 9%). But whereas winter burns promoted the invasive grass Bothriochloa ischaemum by maintaining areas with low canopy cover, summer burns simultaneously limited woody encroachment and controlled B. ischaemum invasion. Our results support a growing body of literature that shows that prescribed fire alone, without the introduction of plant propagules, cannot necessarily restore old-growth grassland community composition. Nonetheless, this long-term experiment demonstrates that prescribed burns implemented in the summer can benefit restoration by preventing woody encroachment while also controlling an invasive grass. We suggest that fire season deserves greater attention in grassland restoration planning and ecological research
The Impact of Public Reporting Schemes and Market Competition on Hospital Efficiency
Get PDFIn the wake of growing attempts to assess the validity of public reporting, much research has examined the effectiveness of public reporting regarding cost or quality of care. However, relatively little is known about whether transparency through public reporting significantly influences hospital efficiency despite its emerging expectations for providing value-based care. This study aims to identify the dynamics that transparency brought to the healthcare market regarding hospital technical efficiency, taking the role of competition into account. We compare the two public reporting schemes, All-Payer Claims Database (APCD) and Hospital Compare. Employing Data Envelopment Analysis (DEA) and a cross-sectional time-series Tobit regression analysis, we found that APCD is negatively associated with hospital technical efficiency, while hospitals facing less competition responded significantly to increasingly transparent information by enhancing their efficiency relative to hospitals in more competitive markets. We recommend that policymakers take market mechanisms into consideration jointly with the introduction of public reporting schemes in order to produce the best outcomes in healthcare
Molecular Phylogenetics of the New-World Crocodylia
No full textDuring the late twentieth and early twenty-first centuries, there has been a revolution in evolutionary biology. Traditional methods that had been applied to understanding relationships and natural history for hundreds of years have been supplemented (and sometimes replaced) by biochemical and molecular techniques that now allow us to examine the entire genomes of non-model organisms. Herein we review the use of these new technologies as they apply to crocodylians in general and specifically to the New-World members of the Alligatoridae and Crocodylidae. While generally concordant with traditional analyses, in some cases they have permitted cryptic species to be recognized. In addition, they have allowed crocodylian biologists to detect hybridization events between species, both in captivity and in the wild, that would not have been possible before their use. Hybridization may lead to the formation of new species, but it may also allow a common species to “swamp out” a rarer one. Because there appears to be little hybrid dysgenesis between many of the potential hybridizing forms, hybridization is potentially a serious problem for several New-World species
Between Values and Action: Religious Rhetoric, Human Rights, and Reagan\u27s Foreign Policy
No full textThe Effect of Freespace Properties on Unilateral Stiffness Classification
Get PDFVirtual environments rendered through kinesthetic haptic devices have frequency-dependent dynamic properties that affect perception. Previous studies on the perception of virtual walls have suggested that the properties not only of the wall, but also of the freespace with which it is paired, influence the perceived wall stiffness (bias) and discrimination thresholds. In this work, two experiments were undertaken to examine the effect of mass and damping properties in freespace on virtual wall stiffness classification. The results suggest that there may be alterations to classification performance under large changes in freespace conditions, but that small changes in mass and damping do not appear to significantly affect performance. These results suggest that additional study is needed to fully understand the effects of freespace properties on wall stiffness classification, which may differ from their effects on discrimination or bias
Optimization of a Rapid and Oxygen Tolerant Fluorogenic Atom Transfer Radical Polymerization Assay for Analyte Detection
No full textIn order to generate an efficient detection assay, an analyte’s signal must be amplified to provide a detectable readout in a short time period. Polymerization reactions can be used to amplify a signal, as a single initiator molecule can incite formation of a long polymer chain. Previous research in the Cooley Lab has led to the development of a novel detection assay using an aqueous atom transfer radical polymerization (ATRP) reaction. This assay provides real-time readouts of polymerization progress by using fluorogenic monomers—monomers that are dark in their monomer form but fluoresce under UV light when incorporated into a polymer—to couple the presence of analyte to fluorescence in solution. Though encouraging, the practicality of the originally reported assay was limited by long reaction times and oxygen intolerability. In order to further develop this assay for optimized capabilities of detection, it was necessary to optimize the reaction to achieve the maximum fluorescence possible in the shortest reaction time. A thorough optimization study was conducted, involving the analysis of several fluorogenic ATRP reaction variables and their effects on fluorescence and reaction kinetics. Various surfactants were screened and characterized, the reaction solvent was manipulated, and components of the reaction’s catalyst system were tested. Through the combination of the optimized reaction components, the average reaction time was reduced from 24 hours to 1.5 hours, maximum fluorescence was increased, and the assay was made more tolerant to oxygen. Modifications of this assay— to incorporate enzymatic oxygen scavenging and to apply the method to the analysis of general radical polymerization kinetics— are also explored and are the subject of ongoing study
Act or Be Acted Upon: Revolutionizing Accounting Curriculums with Data Analytics
No full textTechnology is revolutionizing accounting. To survive, accountants must focus on areas where they can complement technology and carve out a competitive advantage where the expertise of accountants is uniquely needed. To do so, we highlight the new core competencies emphasizing the use of data analytics. We propose a new, revolutionized curriculum focusing on (1) providing students with a step-by-step framework/approach for analyzing the data that includes the use of statistics; (2) using data analytics across the accounting curriculum to build data analytics skills; and (3) incorporating the use of real-world data for its analysis. This new curriculum combines business acumen to provide context as well as technological adeptness to analyze the data, and prepares the CPA professional for the future. We conclude by arguing that the accounting profession faces a choice: either master technology or be mastered by technology. The choice is ours. Act or be acted upon
Understanding Drivers of Variation and Predicting Variability Across Levels of Biological Organization
No full textDifferences within a biological system are ubiquitous, creating variation in nature. Variation underlies all evolutionary processes and allows persistence and resilience in changing environments; thus, uncovering the drivers of variation is critical. The growing recognition that variation is central to biology presents a timely opportunity for determining unifying principles that drive variation across biological levels of organization. Currently, most studies that consider variation are focused at a single biological level and not integrated into a broader perspective. Here we explain what variation is and how it can be measured. We then discuss the importance of variation in natural systems, and briefly describe the biological research that has focused on variation. We outline some of the barriers and solutions to studying variation and its drivers in biological systems. Finally, we detail the challenges and opportunities that may arise when studying the drivers of variation due to the multi-level nature of biological systems. Examining the drivers of variation will lead to a reintegration of biology. It will further forge interdisciplinary collaborations and open opportunities for training diverse quantitative biologists. We anticipate that these insights will inspire new questions and new analytic tools to study the fundamental questions of what drives variation in biological systems and how variation has shaped life
Arsenic in Petroleum-Contaminated Groundwater Near Bemidji, Minnesota is Predicted to Persist for Centuries
Get PDFWe used a reactive transport model to investigate the cycling of geogenic arsenic (As) in a petroleum-contaminated aquifer. We simulated As mobilization and sequestration using surface complexation reactions with Fe(OH)3 during petroleum biodegradation coupled with Fe-reduction. Model results predict that dissolved As in the plume will exceed the U.S. and EU 10 µg/L drinking water standard for ~400 years. Non-volatile dissolved organic carbon (NVDOC) in the model promotes As mobilization by exerting oxygen demand, which maintains anoxic conditions in the aquifer. After NVDOC degrades, As re-associates with Fe(OH)3 as oxygenated conditions are reestablished. Over the 400-year simulation, As transport resembles a “roll front” in which: (1) arsenic sorbed to Fe(OH)3 is released during Fe-reduction coupled to petroleum biodegradation; (2) dissolved As resorbs to Fe(OH)3 at the plume’s leading edge; and (3) over time, the plume expands, and resorbed As is re-released into groundwater. This “roll front” behavior underscores the transience of sorption as an As attenuation mechanism. Over the plume’s lifespan, simulations suggest that As will contaminate more groundwater than benzene from the oil spill. At its maximum, the model simulates that ~5.7× more groundwater will be contaminated by As than benzene, suggesting that As could pose a greater long-term water quality threat than benzene in this petroleum-contaminated aquifer