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Comparisons between the hominin or Neogene mammal fossil record and contemporaneous paleoclimate proxies have been commonplace since the pioneering studies of Elisabeth Vrba (1980, 1992, 1995a, 1995b). Vrba combined the new macroevolutionary theories of punctuated equilibrium and species selection (e.g., Eldredge and Gould, 1972; Vrba, 1985b) with emerging evidence for global climate change in the Plio-Pleistocene (e.g., Shackleton et al., 1990) to produce testable hypotheses of faunal turnover pulses in the Neogene fossil record. Vrba focused her analyses on the speciose Neogene bovids, rather than hominins, to ensure statistically robust results. Periods of bovid, and by inference hominin, turnover (origination, extinction and migration) between 2.8 and 2.5 Ma and at ~1.8 Ma were linked to episodes of global cooling seen in the global stable isotope records (Vrba, 1995b). Behrensmeyer et al. (1997) argued that Vrba’s turnover pulses were predominantly a product of sampling bias, by showing that bovid diversity and the number of bovid-bearing localities covaried. A study by deMenocal (1995) was the first to take Vrba’s hypothesis a step further by replacing the bovid fossil record with the hominin fossil record and suggesting that African aridity was behind the evolution of early Homo at approximately 2.0 Ma. This study took the hominin fossil record at face value despite its far greater incompleteness relative to the bovids, paving the way for a new wave of paleoclimatic theories. Potts (1996, 1998a, 1998b) took the debate further from Vrba’s original approach by dispensing with the notion of a shared climatic forcing between hominins and other mammals and proposed the Variability Selection (VS) hypothesis. The VS hypothesis is formulated around the idea that early hominins evolved unique adaptions for ecological versatility in response to climatic variability, so the fossil record of other mammal groups cannot be used to falsify the hypothesis. More recent iterations of the VS hypothesis (such as Maslin and Trauth, 2009; Shultz and Maslin, 2013; Maslin et al., 2014) also rely exclusively on the hominin fossil record as the explicit test case for their hypothesis.
New guidelines for peanut allergy prevention in high-risk infants recommend introducing peanut during infancy but do not address breastfeeding or maternal peanut consumption. We assessed the independent and combined association of these factors with peanut sensitization in the general population CHILD birth cohort (N = 2759 mother–child dyads). Mothers reported peanut consumption during pregnancy, timing of first infant peanut consumption, and length of breastfeeding duration. Child peanut sensitization was determined by skin prick testing at 1, 3, and 5 years. Overall, 69% of mothers regularly consumed peanuts and 36% of infants were fed peanut in the first year (20% while breastfeeding and 16% after breastfeeding cessation). Infants who were introduced to peanut early (before 1 year) after breastfeeding cessation had a 66% reduced risk of sensitization at 5 years compared to those who were not (1.9% vs. 5.8% sensitization; aOR 0.34, 95% CI 0.14–0.68). This risk was further reduced if mothers introduced peanut early while breastfeeding and regularly consumed peanut themselves (0.3% sensitization; aOR 0.07, 0.01–0.25). In longitudinal analyses, these associations were driven by a higher odds of outgrowing early sensitization and a lower odds of late-onset sensitization. There was no apparent benefit (or harm) from maternal peanut consumption without breastfeeding. Taken together, these results suggest the combination of maternal peanut consumption and breastfeeding at the time of peanut introduction during infancy may help to decrease the risk of peanut sensitization. Mechanistic and clinical intervention studies are needed to confirm and understand this “triple exposure” hypothesis.
Two broad aims drive weed science research: improved management and improvedunderstanding of weed biology and ecology. In recent years, agriculturalweed research addressing these two aims has effectively split into separatesubdisciplines despite repeated calls for greater integration. Although someexcellent work is being done, agricultural weed research has developed avery high level of repetitiveness, a preponderance of purely descriptivestudies, and has failed to clearly articulate novel hypotheses linked toestablished bodies of ecological and evolutionary theory. In contrast,invasive plant research attracts a diverse cadre of nonweed scientists usinginvasions to explore broader and more integrated biological questionsgrounded in theory. We propose that although studies focused on weedmanagement remain vitally important, agricultural weed research wouldbenefit from deeper theoretical justification, a broader vision, andincreased collaboration across diverse disciplines. To initiate change inthis direction, we call for more emphasis on interdisciplinary training forweed scientists, and for focused workshops and working groups to developspecific areas of research and promote interactions among weed scientistsand with the wider scientific community.
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