Individual differences in cognitive abilities and skills can predict normatively superior and logically consistent judgments and decisions. The current experiment investigates the processes that mediate individual differences in risky choices. We assessed working memory span, numeracy, and cognitive impulsivity and conducted a protocol analysis to trace variations in conscious deliberative processes. People higher in cognitive abilities made more choices consistent with expected values; however, expected-value choices rarely resulted from expected-value calculations. Instead, the cognitive ability and choice relationship was mediated by the number of simple considerations made during decision making — e.g., transforming probabilities and considering the relative size of gains. Results imply that, even in simple lotteries, superior risky decisions associated with cognitive abilities and controlled cognition can reflect metacognitive dynamics and elaborative heuristic search processes, rather than normative calculations. Modes of cognitive control (e.g., dual process dynamics) and implications for process models of risky decision-making (e.g., priority heuristic) are discussed.

Previous research has shown that glufosinate and nicosulfuron at low rates can cause yield loss to grain sorghum. However, research has not been conducted to pinpoint the growth stage at which these herbicides are most injurious to grain sorghum. Therefore, field tests were conducted in 2016 and 2017 to determine the most sensitive growth stage for grain sorghum exposure to both glufosinate and nicosulfuron. Field test were designed with factor A being the herbicide applied (glufosinate or nicosulfuron). Factor B consisted of timing of herbicide application including V3, V8, flagleaf, heading, and soft dough stages. Factor C was glufosinate or nicosulfuron rate where a proportional rate of 656 g ai ha−1 of glufosinate and 35 g ai ha−1 of nicosulfuron was applied at 1/10×, 1/50×, and 1/250×. Visible injury, crop canopy heights (cm), and yield were reported as a percent of the nontreated. At the V3 growth stage visible injury of 32% from the 1/10× rate of glufosinate and 51% from the 1/10× rate of nicosulfuron was observed. This injury was reduced by 4 wk after application (WAA) and no yield loss occurred. Nicosulfuron was more injurious than glufosinate at a 1/10× and 1/50× rate when applied at the V8 and flagleaf growth stages resulting in death of the shoot, reduced heading, and yield. Yield losses from the 1/10× rate of nicosulfuron were observed from V8 through early heading and ranged from 41% to 96%. Yield losses from the 1/50× rate of nicosulfuron were 14% to 16% at the flagleaf and V8 growth stages respectively. The 1/10× rate of glufosinate caused 36% visible injury 2 WAA when applied at the flagleaf stage, which resulted in a 16% yield reduction. By 4 WAA visible injury from either herbicide at less than the 1/10× rate was not greater than 4%. Results indicate that injury can occur, but yield losses are more probable from low rates of nicosulfuron at V8 and flagleaf growth stages.

A non-GMO trait called Inzen™ was recently commercialized in grain sorghum to combat weedy grasses, allowing the use of nicosulfuron POST in the crop. Inzen™ grain sorghum carries a double mutation in the acetolactate synthase (ALS) gene Val560Ile and Trp574Leu, which potentially results in cross-resistance to a wide assortment of ALS-inhibiting herbicides. To evaluate the scope of cross-resistance to Weed Science Society of America Group 2 herbicides in addition to nicosulfuron, tests were conducted in 2016 and 2017 at the Lon Mann Cotton Research Station near Marianna, AR, the Arkansas Agricultural Research and Extension Center in Fayetteville, AR, and in 2016 at the Pine Tree Research Station near Colt, AR. The tests included ALS-inhibiting herbicides from all five families: sulfonylureas, imidazolinones, pyrimidinylthiobenzoics, triazolinones, and triazolopyrimidines. Treatments were made PRE or POST to grain sorghum at a 1× rate for crops in which each herbicide is labeled. Grain sorghum planted in the PRE trial were Inzen™ and a conventional cultivar. Visible estimates of injury and sorghum heights were recorded at 2 and 4 wk after herbicide application, and yield data were collected at crop maturity. In the PRE trial, no visible injury, sorghum height reduction, or yield loss were observed in plots containing the Inzen™ cultivar. Applications made POST to the Inzen™ grain sorghum caused visible injury, sorghum height reduction, and yield loss of 20%, 13%, and 35%, respectively, only in plots where bispyribac-Na was applied. There was no impact on the crop from other POST-applied ALS-inhibiting herbicides. These results demonstrate that the Inzen™ trait confers cross-resistance to most ALS-inhibiting herbicides and could offer promising new alternatives for weed control and protection from carryover of residual ALS-inhibiting herbicides in grain sorghum.

Management practices and cropping systems that serve as integrated weed management practices, and at the same time can contribute to improved soil quality, will be important for the sustainability of agricultural production systems. The objective of this study was to assess weed species population density under contrasting tillage (conventional tillage [CT] and no tillage [NT]), residue burning (burn and no burn), and residue level (low and high) treatments after 5 and 6 yr of consistent management in a wheat–soybean double-crop production system. A field experiment was conducted from fall 2001 to fall 2007 in the Mississippi River Delta region of eastern Arkansas on a Calloway silt–loam. Weed assessments were conducted twice during the soybean growing season, before (early season) and after herbicide application (late season) in 2006 and 2007. Total weed density was greater under CT (513 plants m−2) than under NT (340 plants m−2) early in the growing season in 2006, but was greater under NT than CT late in the season in 2007, suggesting that the effectiveness of glyphosate on total weeds differs between CT and NT. Averaged across residue levels, grass species density was greatest in the NT–burn (68 to 167 plants m−2) combination and lowest in the NT–no-burn (41 to 63 plants m−2) early in the growing season in both years. Broadleaf density was greater early (200 to 349 plants m−2) than late (18 to 20 plants m−2) in the growing season under both CT and NT in 2006, but in 2007 broadleaf density did not differ by tillage treatment between seasons. Perennial weed density was greater in the burn (99 plants m−2) than in the no-burn (59 plants m−2) treatment in 2006. No tillage, no burning, and a high residue level appeared to contribute to the suppression of most weed species without reducing herbicide efficiency.

With “Unfinished Migrations,” Patterson and Kelley have provided an indispensable overview of the recent resurgence of African diaspora scholarship. Describing this “rebirth” in light of contemporary concerns with globalization and transnationalism, they usefully update the work of scholars such as St. Clair Drake, Joseph Harris, and George Shepperson, who over the past thirty-five years have provided similar catalogues and calls.

Rather than contest any particular element of their overview, I will focus briefly on what I consider to be some crucial issues of epistemological strategy raised by their salutary attempt to conceptualize a “theoretical framework… that treats the African diaspora as a unit of analysis.” The first is that we need to consider in more detail the genealogy of the term diaspora itself. Patterson and Kelley are correct to note that “attempts to identify and make sense of the African diaspora are almost as old as the diaspora itself,” but surely it is also significant that the term diaspora has been appropriated so recently in black intellectual discourse. Writers and activists including Equiano, Blyden, Delany, Du Bois, and Nardal proposed varying visions of internationalism over the past two centuries, but only in the past three decades have black intellectuals turned to an explicit discourse of an “African diaspora.” It seems to me that we need to be able to explain why this term arises, as Patterson and Kelley point out, only in the late 1950s and early 1960s.

We have been developing X-ray calorimeters that have high spectral resolution and high quantum efficiency. For an X-ray calorimeter working at 0.1 K, the energy resolution ideally can be as good as one eV for a practical detector. A detector with a resolution of 17 eV FWHM at 6 keV has been constructed. We expect to be able to improve this by a factor of two or more. With X-ray calorimeters flown on a sounding rocket, we should be able to observe soft X-ray line emission from the interstellar medium over the energy range 0.07 to 1 keV. Here we present a preliminary design for an X-ray calorimeter rocket experiment and the spectrum which might be observed from an equilibrium plasma. For later X-ray calorimeter sounding rocket experiments, we plan to add an aluminum foil mirror with collecting area of about 400 cm2 to observe line features from bright supernova remnants.