Southern Illinois University is a system of public universities in the southern region of the U.S. state of Illinois. Its headquarters is in Carbondale, Illinois.
Impulsive choice is the suboptimal preference for a smaller-sooner (SS, “impulsive”) option over a larger-later (LL, “self-controlled”) option. Fixed-interval (FI) training delivers delayed-reinforcement trials to increase LL choices and improve FI timing precision. While there are plenty of studies exploring the neurobiological factors underlying impulsive choice, it is unknown what neurobiological changes account for the FI training effects. The prelimbic cortex (PL) region is implicated in both impulsive choice and timing. To investigate the role of the PL, we used designer receptors exclusively activated by designer drugs (GiDREADDs) to reversibly inhibit the PL during either the FI training phase or the follow-up impulsive choice task in male and female Sprague-Dawley rats. Compared to a control group, the GiDREADDs rats showed reduced LL choices when CNO was administered during the FI training or impulsive choice tasks. GiDREADDS did not alter response rates or latency to choose. Overall, these data demonstrate that inhibition of the PL increases impulsive choice and may block the effect of the FI training to improve self-control. ### Competing Interest Statement The authors have declared no competing interest. National Institutes of Health, https://ror.org/01cwqze88
Incorporation of evolutionary theory into experimental investigations of natural populations was important to the development of plant ecology. We review the prominent role grasses (Poaceae) have played in this historical development. Beginning in the 1920s, the ecotype concept prompted researchers to investigate genetically based differentiation in agronomically important forage grasses using common gardens, first in relation to climatological and biotic factors (grazing and competition), and later in relation to latitude and elevation at collection sites. Adaptive variation was documented for populations in relation to edaphic factors such as soil nutrients and moisture, salinity, serpentine conditions, and heavy metals. Molecular analyses using allozyme and DNA markers show selection favors specific genetic loci in grass populations from different habitats or under changing climatic conditions. Consistent with theoretical expectations for breeding-system effects on genetic structure, highly outcrossing grass species show lower molecular variation among populations and greater variation within populations. In contrast, highly selfing grasses show more genetic variation partitioned among populations and correspndingly reduced variation within populations. Progress has been made in identifying quantitative trait loci important to genetic differentiation in phenotypic traits. Biotic factors such as herbivory, competition and microbial symbionts can act as agents of natural selection and adaptation in grass species. Despite inconsistencies in usage, “ecotype” persists in the literature, but the term has value as evidenced by recent adaptation studies in the Poaceae. Applications of the ecotype concept include reclamation and phytoremediation of sites polluted by metalliferous wastes, restoration of habitats, evolutionary responses to a changing climate, and adaptation of weedy and invasive species.
We examine associations between management earnings forecasts and capital structure. We posit that incremental information in forecasts reduces capital providers' concerns about adverse selection. Pecking order theory suggests forecasts contribute differing amounts of information to different capital providers, shifting capital structure from trade credit to long-term debt, and from long-term debt to equity. Investment information risk theory submits that although creditors and equity holders share downside risk, creditors are more sensitive than equity holders to uncertainty related to the riskiness of firms' future investments because equity holders are the sole beneficiaries of investments' upside potential. Insomuch earnings forecasts provide investment information that is more meaningful to creditors, we expect a shift in capital structure from equity to credit as the forecast decreases outcome uncertainty. Using a sample of US-listed firms from 2003 to 2019, we find support for the pecking order theory, that firms issuing management earnings forecasts exhibit higher levels of equity-to-credit financing and long-term debt-to-trade credit financing. However, in cross-sectional tests, we also find evidence supporting the investment information risk theory, that forecasts shift financing from equity to credit and among creditors, from long-term debt to trade credit in firms with more growth opportunities. Our findings suggest firms' voluntary disclosures provide different amounts of incremental information to different capital providers, but that the relevance of the information provided may also differ across capital providers.
Past restoration of hardwood forests prioritized planting of woody vegetation cover, particularly oaks (Quercus spp.). This restoration regime often did not consider other microhabitat components, which failed to restore habitat complexity. Giant cane (Arundinaria gigantea (Walter) Muhl.) was an important microhabitat feature for creating a dense understory structure within the hardwood forest landscape. Many bird species are associated with stands of giant cane (canebrakes) for food, cover, and nesting ground. The decline of canebrakes may reduce nesting and foraging habitat, negatively impacting bird communities. Here, we used a hierarchical multi-species occupancy model to assess how giant cane and its associated overstory forest structure influenced breeding bird occupancy in southern Illinois. Bird surveys were conducted from May to July 2022-2024 at 100 site-years using passive acoustic monitoring. Responses to the vegetation structure (tree density and size) and canebrakes varied among species and nesting guilds (overstory, understory, and ground). Occurrence probabilities of 54% of the bird species increased with the presence of canebrake. We did not find any significant relationships between bird occupancy and vegetation structure and canebrake characteristics. Overall, maintaining a hardwood forest stand with a heterogeneous canopy cover would create variations in light environments, allowing canebrakes to benefit bird species across nesting guilds.
Considering variations in price convergence rates as indicators of economic agents' adaptability, we examine the impact of the 2008 Great Recession on price convergence across U.S. cities. Using a combination of comparative and regression analysis, we analyse quarterly retail price data for 51 commodities across 284 cities from 1992 Q1 to 2019 Q3. The comparative analysis reveals that the speed of price convergence increased or accelerated for most commodities following the Great Recession, with the effect being more pronounced for non-perishable goods. Moreover, the gap in convergence rates between the most and least affected areas widened, as the most affected regions experienced significantly faster convergence after the recession. The regression analysis disentangles the effects of the Great Recession, revealing relatively more instances of temporary, delayed, or sustained accelerating impacts, especially for perishable and non-perishable tradable goods.
