Innocent until Primed: Mock Jurors’ Racially Biased Response to the Presumption of Innocence

Background: Research has shown that crime concepts can activate attentional bias to Black faces. This study investigates the possibility that some legal concepts hold similar implicit racial cues. Presumption of innocence instructions, a core legal principle specifically designed to eliminate bias, may instead serve as an implicit racial cue resulting in attentional bias. Methodology/Principal findings: The experiment was conducted in a courtroom with participants seated in the jury box. Participants first watched a video of a federal judge reading jury instructions that contained presumption of innocence instructions, or matched length alternative instructions. Immediately following this video a dot-probe task was administered to assess the priming effect of the jury instructions. Presumption of innocence instructions, but not the alternative instructions, led to significantly faster response times to Black faces when compared with White faces. Conclusions/Significance: These findings suggest that the core principle designed to ensure fairness in the legal system actually primes attention for Black faces, indicating that this supposedly fundamental protection could trigger racial stereotypes

Zinc uptake and phyto-toxicity: Comparing intensity- and capacity-based drivers

© 2019 Elsevier B.V. Metal bioavailability and phytotoxicity may be exaggerated when derived from studies based on amending soils with soluble metal salts. It is therefore important to evaluate soil tests for their consistency in estimating plant uptake and phytotoxicity in both field-contaminated and freshly-spiked soils. This study aimed to compare the effects of zinc (Zn) on plant growth in soils (i) recently spiked with soluble Zn and (ii) historically amended with biosolids. The objective was to reconcile methods for determining bioavailability in both cases by testing a range of ‘quantity-based’ and ‘intensity-based’ assays. Soils with a range of Zn concentrations, from an arable farm used for biosolids disposal for over a century, were further amended with Zn added in solution, and were incubated for one month prior to planting with barley seeds in a glasshouse pot trial. The majority (67–90%) of the added Zn remained isotopically exchangeable after 60 days. Zinc in the solution phase of a soil suspension was present mainly as free Zn2+ ions. Cadmium bioaccumulation factors were inversely proportional to Zn concentration in the soil solution confirming that greater Zn availability suppressed Cd uptake by plants. Measurements of soil Zn ‘quantities’ (total, EDTA-extractable and isotopically exchangeable) and ‘intensity’ (solution concentration and free ion activity) were correlated with Zn uptake and toxicity by barley plants. Correlations using Zn intensity were much stronger than those using quantity-based measurements. The free Zn2+ ion activity appears to be a consistent driver for plant uptake and phytotoxic response for both metal-spiked soils and historically contaminated soils. Surprisingly, soil Zn accumulation of up to 100 times the current regulations for normal arable land only produced a mild toxic response suggesting that constituents in biosolids (e.g. organic matter and phosphates) strongly restrict metal bioavailability

The influence of style and origin on mineral composition of beers retailing in the UK

Beer has high nutritional values in terms of energy and is also a dietary source of antioxidants, carbohydrates and minerals among others. In Europe, 53 Mt of beer are produced annually, and with an average supply of 68.2 kg capita‾¹ year‾¹ among adults. In this study, the mineral composition of 125 commercial beer samples retailing in the UK, but originating from ten countries, was determined; such detailed information is lacking in UK food composition tables. Beer composition data are reported for Al, As, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Se, Sr, U, V and Zn, following analysis by inductively coupled plasma mass spectrometry. ANOVA results showed higher concentrations of Mo, Pb and Sr (0.160; 491.70 × 10‾⁵; 0.38 mg L‾¹, respectively) for stout/porter style and a significant higher amount of minerals such as Al (3.835 mg L−1), Cd (8.64 × 10−5 mg L‾¹), Mn (1.02 mg L‾¹) or Ni (0.312 mg L‾¹) among others for lambic beer. Regarding the country of origin, higher Se concentrations were reported from beer brewed in the USA (0.110 mg L‾¹). It is concluded that beer style was determined to have a greater effect on beer mineral composition than origin or container type

Dislocation-mediated growth of bacterial cell walls

Recent experiments have illuminated a remarkable growth mechanism of rod-shaped bacteria: proteins associated with cell wall extension move at constant velocity in circles oriented approximately along the cell circumference (Garner et al., Science (2011), Dominguez-Escobar et al. Science (2011), van Teeffelen et al. PNAS (2011). We view these as dislocations in the partially ordered peptidoglycan structure, activated by glycan strand extension machinery, and study theoretically the dynamics of these interacting defects on the surface of a cylinder. Generation and motion of these interacting defects lead to surprising effects arising from the cylindrical geometry, with important implications for growth. We also discuss how long range elastic interactions and turgor pressure affect the dynamics of the fraction of actively moving dislocations in the bacterial cell wall.Comment: to appear in PNA

Niche partitioning among and within sympatric tropical seabirds revealed by stable isotope analysis

The low productivity and unpredictable nature of resources in tropical waters would appear to make resource partitioning among predators difficult. Yet, stable isotope data from the present study suggest that substantial resource partitioning occurs among tropical seabird communities, both between and within species. In the present study, we compared δ13C and δ15N levels among 8 sympatric tropical seabird species. For a subset of these species, we also examined isotopic levels across years, breeding periods, and sexes. When breeding and non-breeding periods were both considered, we found that all species occupied distinct isotopic niches across at least one time period. Resource partitioning by age (within the same year) and year studied (for birds of the same age), within species was observed in all the species we examined. However, niche separation by sex appeared to be relatively uncommon even in sexually dimorphic species. As a group, seabirds were isotopically distinct from other marine predators. There was a strong correlation between both body mass and wing loading ratios and foraging area, as evaluated using δ13C levels. Cumulatively, the isotopic patterns observed are consistent with diet-based surveys of resource partitioning during the breeding period. Importantly, these data provide additional evidence to suggest that substantial niche partitioning among tropical seabird species persists even during non-breeding periods in open ocean environments, when direct diet-based surveys are difficult to conduct

Uptake of trace elements by food crops grown within the Kilembe copper mine catchment, Western Uganda

The mining and processing of copper from the Kilembe mine between 1956 and 1982 left behind millions of tons of cupriferous and cobalt ferrous mine tailings within the Kilembe mine catchment. Subsequent erosion and deposition of the tailings into adjacent areas led to increased concentrations of Cu, Co, Ni, Zn, and Pb in the catchment soils. The Kilembe catchment is utilised for subsistence farming, producing mainly food crops, but there are also a number of settlements in the contaminated area. A study was conducted in 2016 to establish the concentrations of trace elements in a range of food crops grown within the catchment. Samples of maize, bananas, cassava, sweet potatoes, ground nuts, amaranthus, onions, beans and yams were collected, washed and oven dried at 80 °C. The dried foods were finely ground, microwave- digested in nitric acid and analysed using inductively coupled plasma mass spectrometry (ICPMS). All the foods grown in contaminated soils showed instances of higher concentrations of Cu, Co, Ni, Zn, and in some cases Pb, compared with controls grown in uncontaminated soils. Amaranthus accumulated a range of trace elements with 26% of the samples exceeding EC thresholds for Cu in vegetables of 26 mg kg−1.Other crops with elemental concentrations exceeding recommended thresholds in some of the samples included beans (Zn), yams (Zn and Pb) and ground nuts (Zn). The concentrations of trace elements in onions, cassava, sweet potatoes, bananas and maize were not significantly different from controls. However, strong and positive correlations between the trace elements were found in beans, yams, amaranthus, maize and ground nuts, suggesting a common source of trace metals. There was strong evidence of soil dust retention on leaf vegetables (Amaranthus) despite washing. The accumulation of trace elements in the edible parts of vegetables and foods could have a direct impact on the health of local people, because the foods produced from gardens are mostly consumed locally