The effect of temporally variable environmental stimuli and group size on emergence behavior

How animals trade-off food availability and predation threats is a strong determinant of animal activity and behavior; however, the majority of work on this topic has been on individual animals, despite the modulating effect the presence of conspecifics can have on both foraging and predation risk. Although these environmental factors (food and predation threat) vary spatially within habitats, they also vary temporally, and in marine habitats, this can be determined by not only the diel cycle but also the tidal cycle. Humbug damselfish, Dascyllus aruanus, live in small groups of unrelated individuals within and around branching coral heads, which they collectively withdraw into to escape a predation threat. In this study, we measured the proportion of individuals in the colony that were outside the coral head before and after they were scared by a fright stimulus and compared the responses at high tide (HT) and low tide (LT). We found that a greater proportion of the shoal emerged after the fright stimulus at HT and in larger groups than at LT or in smaller groups. We also quantified the pattern of emergence over time and discovered the rate of emergence was faster in larger shoals as time progressed. We show that shoals of fish change their behavioral response to a predation threat in accordance with the tide, exemplifying how temporally variable environmental factors can shape group movement decisions

No Property In Man: Slavery and Antislavery at the Nation’s Founding

Noted historian Sean Wilentz offers a weighty and sure-to-be controversial contribution to the extensive historiography on slavery and the original intent of the Constitution. Many historians agree the Constitution was, explicitly or implicitly, a proslavery document, ratified by elite white men many of whom had an interest in slavery as an American institution. But Wilentz contends that the Constitution was more ambivalent toward slavery—even indirectly antislavery in its language—than most scholars acknowledge. The Constitution’s limited protection of slavery could not be equated to the recognition of slavery as a permanent institution. The national governing document failed to specifically recognize property in man and thus left slavery as a creation of the individual states, an important distinction for Wilentz and one that provided the political space necessary for antislavery constitutionalism to thrive in the first half of the nineteenth century. Antislavery efforts ignited in earnest with Vermont’s 1777 ban on slavery and grew with such force that the provisions for slavery’s protection placed in the Constitution were hard won despite antislavery’s powerful presence at the 1787 convention. If antislavery rhetoric and ideology grew increasingly radical before the 1860s, so too then did proslavery assertions about the Constitution, Wilentz argues

Occupied Vicksburg

The Cultural Work of Military Occupation With Occupied Vicksburg, Bradley R. Clampitt contributes a well-researched monograph about Union military occupation in the Confederate South to a field that has been slowly burgeoning over the years. Clampitt skillfully balances heady discussions of ...

X-ray Absorption Fine Structure and X-ray Excited Optical Luminescence Studies of Gallium Nitride - Zinc Oxide Solid Solution Nanostructures

Gallium nitride – zinc oxide (GaN-ZnO) solid solutions have been realized as potential photocatalysts for overall water splitting due to a narrowing of the band-gap into the visible region of the solar spectrum. Although there has been much experimental and theoretical work on this novel class of semiconductors many questions about the nature of their electronic and chemical properties remain unanswered. In particular the mechanism of band-gap reduction in these materials is not clearly understood. It is also unclear what the local chemical environment of gallium, zinc, nitrogen, and oxygen is in both the surface and bulk of these solid solutions. These materials have unusual optical emission properties exhibiting broad visible emission bands that are substantially red-shifted from observed band-gap energies. Since crystallinity, electronic structure, defects, and local chemical environments (both bulk and surface) all affect photocatalytic efficiency further understanding of the aforementioned properties of these materials is necessary. The focus of this thesis is on the analysis of GaN-ZnO nanostructures by X-ray absorption fine structure (XAFS), including the near edge region, X-ray absorption near edge structure (XANES) and the extended region, extended X-ray absorption fine structure (EXAFS) to further the understanding of the local chemical environment (both bulk and surface) and structure of these materials using tunable X-rays from a synchrotron light source. X-ray excited optical luminescence (XEOL) has also been used to study the optical emission and near-band-gap (NBG) properties of these materials. From XANES it has been shown that there is local chemical disorder of gallium nitride and zinc oxide phases upon solid solution formation, but, there is also strong short-range order which is evident in the EXAFS. XEOL studies have revealed that optical luminescence observed from these materials is of complex origins including zinc-related acceptor levels in the bulk and defects in the complex surface oxide. Preliminary results from time-resolved XEOL experiments have provided evidence of two NBG emission components related to GaN and ZnO phases in the material respectively. These results suggest that band-gap reduction observed in these materials is due to repulsion between conduction band onsets at phase interfaces within a disordered solid solution

Future Proof and Real-World Ready: The Role of Live Project-Based Learning in Students’ Skill Development

The rapid pace of technological change taking place today makes it even more important for marketing educators to incorporate relevant technical and higher level meta-skills in their digital marketing courses. We review the pedagogical literature on skill development and project-based learning and detail two live course projects designed to help students develop technical skills related to digital marketing in addition to important meta-skills involving creativity, critical thinking, collaboration, and communication. We evaluate the impact of the projects through a direct and indirect assessment process. Findings suggest that live project–based learning can support the development of the technical and meta-skills necessary for students to adapt to uncertainty and ambiguity and become future proof and real-world ready as they enter the workforce. We discuss the benefits and challenges associated with moving digital marketing education from conceptual to real-life projects and highlight pedagogical recommendations for educators who want to integrate live project-based learning into their courses

Coastal Forest Seawater Exposure Increases Stem Methane Concentration

Methane (CH4) exchange between trees and the atmosphere has recently emerged as an important, but poorly quantified process regulating global climate. The sources (soil and/or tree) and mechanisms driving the increase of CH4 in trees and degassing to the atmosphere are inadequately understood, particularly for coastal forests facing increased exposure to seawater. We investigated the eco‐physiological relationship between tree stem wood density, soil and stem oxygen saturation (an indicator of redox state), soil and stem CH4 concentrations, soil and stem carbon dioxide (CO2) concentrations, and soil salinity in five forests along the United States coastline. We aim to evaluate the mechanisms underlying greenhouse gas increase in trees and the influence of seawater exposure on stem CH4 accumulation. Seawater exposure corresponded with decreased tree survival and increased tree stem methane. Tree stem wood density was significantly correlated with increased stem CH4 in seawater exposed gymnosperms, indicating that dying gymnosperm trees may accumulate higher levels of CH4 in association with seawater flooding. Further, we found that significant differences in seawater exposed and unexposed gymnosperm tree populations are associated with increased soil and stem CH4 and CO2, indicating that seawater exposure significantly impacts soil and stem greenhouse gas abundance. Our results provide new insight into the potential mechanisms driving tree CH4 accumulation within gymnosperm coastal forests

A Fast Potential and Self-Gravity Solver for Non-Axisymmetric Disks

Disk self-gravity could play an important role in the dynamic evolution of interaction between disks and embedded protoplanets. We have developed a fast and accurate solver to calculate the disk potential and disk self-gravity forces for disk systems on a uniform polar grid. Our method follows closely the method given by Chan et al. (2006), in which an FFT in the azimuthal direction is performed and a direct integral approach in the frequency domain in the radial direction is implemented on a uniform polar grid. This method can be very effective for disks with vertical structures that depend only on the disk radius, achieving the same computational efficiency as for zero-thickness disks. We describe how to parallelize the solver efficiently on distributed parallel computers. We propose a mode-cutoff procedure to reduce the parallel communication cost and achieve nearly linear scalability for a large number of processors. For comparison, we have also developed a particle-based fast tree-code to calculate the self-gravity of the disk system with vertical structure. The numerical results show that our direct integral method is at least two order of magnitudes faster than our optimized tree-code approach.Comment: 8 figures, accepted to ApJ

USING OTOLITH MICROCHEMISTRY TO CLASSIFY YELLOW PERCH AS STOCKED OR NATURALLY PRODUCED

Fisheries managers routinely use stocking to supplement fish populations (Schramm and Piper 1995, Fisher 1996). Stocking eyed-eggs offers substantial cost savings compared to stocking fry and fingerlings (PFBC 2011); however, traditional stocking evaluation using oxytetracycline (OTC) marking of otoliths is ineffective for eyed-eggs of some species (e.g., yellow perch, [Perca fla- vescens]). Thus, there is a need for additional approaches to be able to classify fish as stocked or naturally produced. Fish otoliths are paired calcified structures in the inner ear that permanently deposit trace elements in proportion to water column concentrations (Campana 1999, Campana et al. 2000). Coupled with otolith growth increments (i.e., annuli), elemental accumulation permits retrospective evaluation of environmental history (e.g., natal origins, movement) if water chemistry is spatially heterogeneous and temporally constant (Elsdon et al. 2008). Otolith microchemistry can be used to evaluate stocking contributions (Pracheil et al. 2014) and in the context of eyed-egg stockings, may be useful for classifying fish as stocked or naturally produced. Yellow perch is a popular sport fish species in South Dakota (Gigliotti 2007) and is routinely stocked by fisheries managers to supplement weak year classes (Schoene- beck et al. 2010). The South Dakota Department of Game, Fish and Parks (SDGFP) propagates yellow perch for stocking (e.g., eyed-eggs, fry, fingerlings) and also stocks adult perch through trap and transfer operations (Lott 1991, Fisher 1996). However, the contributions of yellow perch stockings in South Dakota are largely unknown because it is difficult to differentiate stocked fish from resident individuals (Brown and St. Sauver 2002). Our objective was to assess the utility of otolith microchemistry to distinguish hatchery-reared yellow perch stocked at the eyed-egg stage from naturally produced individuals

The Provision Of Data From The COSMOS-UK Soil Moisture Monitoring Network

This paper describes the data available from COSMOS-UK, a new soil moisture monitoring network for the UK based on passive cosmic-ray moisture probes which are capable of measuring average soil water content over a circular footprint of around 350m in radius and depths of up to 0.5 m. Around 35 probes, with an associated array of meteorological and point soil moisture sensors, will be deployed across the UK in a network designed to best represent a range of soil and land cover types, complement existing scientific monitoring over a wide range of subject areas, and capture the variability in soil moisture over the country. Data will be automatically quality controlled and data streams will be openly and freely accessible via services and formats that conform to existing international standards, enabling integration with forecasting and data assimilation systems

Evaluating the cost-effectiveness of existing needle and syringe programmes in preventing hepatitis C transmission in people who inject drugs

AIM: To evaluate the cost-effectiveness of needle and syringe programmes (NSPs) compared with no NSPs on hepatitis C virus (HCV) transmission in the United Kingdom. DESIGN: Cost-effectiveness analysis from a National Health Service (NHS)/health-provider perspective, utilizing a dynamic transmission model of HCV infection and disease progression, calibrated using city-specific surveillance and survey data, and primary data collection on NSP costs. The effectiveness of NSPs preventing HCV acquisition was based on empirical evidence. SETTING AND PARTICIPANTS: UK settings with different chronic HCV prevalence among people who inject drugs (PWID): Dundee (26%), Walsall (18%) and Bristol (45%) INTERVENTIONS: Current NSP provision is compared with a counterfactual scenario where NSPs are removed for 10 years and then returned to existing levels with effects collected for 40 years. MEASUREMENTS: HCV infections and cost per quality-adjusted life year (QALY) gained through NSPs over 50 years. FINDINGS: Compared with a willingness-to-pay threshold of £20 000 per QALY gained, NSPs were highly cost-effective over a time-horizon of 50 years and decreased the number of HCV incident infections. The mean incremental cost-effectiveness ratio was cost-saving in Dundee and Bristol, and £596 per QALY gained in Walsall, with 78, 46 and 40% of simulations being cost-saving in each city, respectively, with differences driven by coverage of NSP and HCV prevalence (lowest in Walsall). More than 90% of simulations were cost-effective at the willingness-to-pay threshold. Results were robust to sensitivity analyses, including varying the time-horizon, HCV treatment cost and numbers of HCV treatments per year. CONCLUSIONS: Needle and syringe programmes are a highly effective low-cost intervention to reduce hepatitis C virus transmission, and in some settings they are cost-saving. Needle and syringe programmes are likely to remain cost-effective irrespective of changes in hepatitis C virus treatment cost and scale-up