The influence of decision-making in tree ring-based climate reconstructions.

Tree-ring chronologies underpin the majority of annually-resolved reconstructions of Common Era climate. However, they are derived using different datasets and techniques, the ramifications of which have hitherto been little explored. Here, we report the results of a double-blind experiment that yielded 15 Northern Hemisphere summer temperature reconstructions from a common network of regional tree-ring width datasets. Taken together as an ensemble, the Common Era reconstruction mean correlates with instrumental temperatures from 1794-2016 CE at 0.79 (p < 0.001), reveals summer cooling in the years following large volcanic eruptions, and exhibits strong warming since the 1980s. Differing in their mean, variance, amplitude, sensitivity, and persistence, the ensemble members demonstrate the influence of subjectivity in the reconstruction process. We therefore recommend the routine use of ensemble reconstruction approaches to provide a more consensual picture of past climate variability.

Volcanic suppression of Nile summer flooding triggers revolt and constrains interstate conflict in ancient Egypt.

Volcanic eruptions provide tests of human and natural system sensitivity to abrupt shocks because their repeated occurrence allows the identification of systematic relationships in the presence of random variability. Here we show a suppression of Nile summer flooding via the radiative and dynamical impacts of explosive volcanism on the African monsoon, using climate model output, ice-core-based volcanic forcing data, Nilometer measurements, and ancient Egyptian writings. We then examine the response of Ptolemaic Egypt (305-30 BCE), one of the best-documented ancient superpowers, to volcanically induced Nile suppression. Eruptions are associated with revolt onset against elite rule, and the cessation of Ptolemaic state warfare with their great rival, the Seleukid Empire. Eruptions are also followed by socioeconomic stress with increased hereditary land sales, and the issuance of priestly decrees to reinforce elite authority. Ptolemaic vulnerability to volcanic eruptions offers a caution for all monsoon-dependent agricultural regions, presently including 70% of world population.The degree to which human societies have responded to past climatic changes remains unclear. Here, using a novel combination of approaches, the authors show how volcanically-induced suppression of Nile summer flooding led to societal unrest in Ptolemaic Egypt (305-30 BCE).

Financial conflict of interest disclosure and voting patterns at Food and Drug Administration Drug Advisory Committee meetings.

CONTEXT: In January 2002, the US Food and Drug Administration (FDA) issued a draft guidance requiring more detailed financial conflict of interest disclosure at advisory committee meetings. OBJECTIVES: To characterize financial conflict disclosures at drug-related meetings, and to assess the relationship between conflicts and voting behavior at meetings that considered specific products. DESIGN AND SETTING: Cross-sectional study using agendas and transcripts from all FDA Drug Advisory Committee meetings (2001-2004) listed on the FDA Web site. MAIN OUTCOME MEASURES: Conflict rates, type, and size. The relationship between having a conflict and voting in favor of the index drug was described for each voter using Mantel-Haenszel relative risks and Monte Carlo simulations; Spearman rho was used for a meeting-level analysis comparing rates of conflict with voting patterns. The impact of the removal of persons with conflicts of interest on the vote margins was also evaluated. RESULTS: A total of 221 meetings held by 16 advisory committees were included in the study. In 73% of the meetings, at least 1 advisory committee member or voting consultant disclosed a conflict; only 1% of advisory committee members were recused. For advisory committee members (n = 1957) and voting consultants combined (n = 990), 28% (n = 825) disclosed a conflict. The most commonly specified conflicts were consulting arrangements, contracts/grants, and investments. Nineteen percent of consulting arrangements involved over 10,000 dollars, 23% of contracts/grants exceeded 100,000 dollars, and 30% of investments were over 25,000 dollars. The meeting-level analysis did not show a statistically significant relationship between conflict rates ("index conflict," "competitor conflict," or "any conflict") and voting patterns, but a weak, statistically significant positive relationship was apparent for competitor conflict and any conflict in the Mantel-Haenszel analyses. The Monte Carlo analyses produced similar findings in the competitor conflict analysis only. In all 3 conflict categories, the exclusion of advisory committee members and voting consultants with conflicts would have produced margins less favorable to the index drug in the majority of meetings, but this would not have changed whether the majority favored or opposed the drug. CONCLUSIONS: Disclosures of conflicts of interest at drug advisory committee meetings are common, often of considerable monetary value, and rarely result in recusal of advisory committee members. A weak relationship between certain types of conflicts and voting behaviors was detected, but excluding advisory committee members and voting consultants with conflicts would not have altered the overall vote outcome at any meeting studied.